Safecast Report2017: Part 2.1-Issues-at-Fukushima-Daiichi-final

PART 2.1: SITUATION REPORT
Issues at Fukushima Daiichi Nuclear Powerplant

2
Part 2- Situation
Report
August 2017
A note before we start:
The Fukushima crisis continues to evolve
slowly in most respects compared to the
urgent situation in 2011. It is less dynam-
ic in terms of new developments which
demand emergency action, but it is an
ongoing situation with ongoing hazards
and concerns. The passage of time —
over six years at this point — means that
a tremendous amount of information
has accumulated about almost every
aspect of the disaster and its aftermath.
In some fortunate instances, ongoing
research and debate has led to greater
clarification of scientific and other issues,
as more reliable and less uncertain data
has superseded fuzzier early estimates.
In other instances, time has brought us
no closer to clear understanding. During
the first year or two of the accident the
information gaps were huge. Basic in-
formation and data about fundamental
issues regarding its impacts still needed
to be collected and analyzed in order to
answer the most pressing questions. In
terms of scientific research, this phase is
essentially over, and we are now grap-
pling with the proliferation of expert stud-
ies on nearly every aspect. We now know
a lot about the accident, its causes, how
much radiation was released and where
it went, the scale of its initial impacts on
people and the environment, and some
inkling of what long-term effects we
might reasonably expect. There are ar-
eas where we are can identify a lack of
scientific knowledge. There are constant
surprises and unexpected findings. As in
every year since the disaster unfolded, it
is difficult to keep up with these changing
circumstances and new information.
While the core of Safecast’s work is
making crowdsourced environmental
monitoring data freely available online,
we’ve also gathered a large store of data
on issues such as the condition of the
Fukushima Daiichi plant itself, the situa-
tion for evacuees, environmental conse-
quences of the accident, food risks, and
health issues, which we share among
ourselves and which help us focus our
efforts. From the start we have made a
point of talking to researchers regard-
less of their ideological stance on nuclear
power, and over the past several years
have fielded countless questions and
requests for data, which we’ve always
tried to respond to quickly and positively.
The robustness of this dialogue has also
made it possible for us to seek expert
advice and opinion on many related sub-
jects, and to pass this knowledge on to
our community as well.
From time to time we have published in-
depth blog posts on specific subjects,
and made technical backgrounders
available online. We have often point-
ed researchers, journalists, and oth-
ers towards these to help them get up
to speed. Quite a lot of technical infor-
mation and many scientific reports are
discussed, sometimes heatedly, on the
Safecast Radiation Discussion Google
Group. Volume 1 of the Safecast Re-
port, <http://blog.safecast.org/the-safe-
cast-report/> released online in March
2015, was an attempt to make this kind
of information more accessible. It was
followed by Volume 2 in March 2016.
You are now reading Volume 3, compiled
in August 2017. The following Situation
Report is an attempt to collate and sum-
marize the most relevant, current, and
accurate information we are aware of
on the major aspects of the Fukushima
disaster and make it available as a refer-
ence for anyone who is interested or has
a need to know. In the following sections

3
we describe the current situation at the
Fukushima Daiichi site itself, for the en-
vironment in general, for food, and for
people’s health, and cite our sources of
information in each case. We strive for
accuracy and readability, as well as com-
pleteness, and rather than attempt to
include every piece of information we’re
aware of, we have prioritized presenting
a coherent summary informed by what
we know, which will point readers to
where they can find more in-depth infor-
mation to inform themselves. We provide
extensive links to relevant documents
wherever possible. Like the prior vol-
umes, Volume 3 of the Safecast Report is
intended to be a stand-alone document
which avoids as much as possible requir-
ing readers to refer to Volume 1 or 2 for
important information. Relevant changes
and new developments are noted, while
some basic background and other infor-
mation remains largely unchanged.
Every aspect of this disaster is accompa-
nied by controversy, and we try to guard
against our own biases and strive to be
as open and inclusive as possible. Some
people will undoubtedly find that our in-
formation in some places contradicts
what they’ve read elsewhere. Others will
feel we do not give sufficient weight to
one opinion or another. We have con-
centrated on finding the best-docu-
mented sources, and have attempted to
evaluate the evidence dispassionately.
We welcome criticism, and urge anyone
who would like to point out contradictory
data not to hesitate to do so. As always
we will welcome that input, and would
be pleased with any feedback which will
help us improve our efforts.
About information sources
The reliability of information has always
been a major issue affecting public un-
derstanding of the Fukushima disaster,
and in fact the lack of reliable information
during the early stages of the disaster
was the reason Safecast was founded.
Official statements concerning ambient
radiation levels in the environment, and
to a lesser degree soil contamination,
can be crosschecked against citizen
science and independent academic re-
search in most cases. Radiation levels
and impacts in the ocean, with the ex-
ception of the immediate vicinity of Daii-
chi, have been very well documented by
independent researchers, in a way which
provides a useful cross-check against of-
ficial claims concerning releases of con-
taminated water to the ocean, etc.. Food
testing data from many independent
groups is available in addition to that from
the government. There has been little or
no systematic third-party verification of
the decontamination process itself, but
radiation levels can be easily confirmed
for most locations if desired. Verifying the
health monitoring done by the national
and Fukushima Prefecture governments
presents a higher technical hurdle, but
several well-done health screening pro-
grams run by local governments as well
as by community groups and founda-
tions allow many useful comparisons to
be made.
But for understanding what’s happen-
ing onsite at the Daiichi plant itself, we
are forced to depend on data provided
by TEPCO almost exclusively, much of
it presented with an obvious PR spin.
Because there is almost no independent
verification of measurements and work
onsite, TEPCO data has an inherent un-
verifiability which in some cases can be
significant. Safecast has consistently
pushed for third-party verification of ra-
diation monitoring at the Daiichi site and
elsewhere, and while some TEPCO staff
and gov’t agency employees have pri-
vately agreed that it would be beneficial
for everyone, including for TEPCO itself,
to adopt this kind of policy, none of our

4
proposals have been accepted so far.
Other qualified groups and researchers
we know have made similar proposals
and have also been rebuffed. We won’t
give up, and will continue to press for the
inclusion of third-party monitoring as a
matter of course. Transparency benefits
all.
Partly in response to this kind of criticism,
in March 2015 TEPCO announced a new
“disclosure” policy under which all on-
site measurement data would quickly be
made publicly available. As will be not-
ed below, while this data can be helpful,
and TEPCO seems to be taking their dis-
closure mandate seriously, it is relatively
hard to locate at first (see links below).
TEPCO: Tepco Announces New Dis-
closure Policy And Independent Audit
Of Drainage Water Issue; Says Find-
ings Will Be Public By End Of March;
March 6, 2015
http://www.tepco.co.jp/en/press/corp-
com/release/2015/1248564_6844.html
Japan Today: TEPCO to make all data
on radiation at Fukushima plant public
Mar. 31, 2015
http://www.japantoday.com/category/
national/view/tepco-says-it-will-make-
all-data-on-radiation-at-fukushima-
plant-public?utm_campaign=jt_newslet-
ter&utm_medium=email&utm_source=-
jt_newsletter_2015-03-31_PM
Asahi: TEPCO to come clean on radi-
ation levels, allow checks by outside
experts March 31, 2015
http://ajw.asahi.com/article/0311disas-
ter/fukushima/AJ201503310040
Most announcements and news articles
about this disclosure policy note that
TEPCO said it will allow regular checks
by third parties. We can only confirm that
this is happening for tests of water in-
tended to be released into the ocean af-
ter purification. The only third parties that
have been approved for this testing to
date are JAEA and the Japan Chemical
Analysis Center (JCAS). JAEA is a gov-
ernment agency, and the Japan Chem-
ical Analysis Center, while independent,
has close government ties. Both entities
have the requisite technical capabilities
and experience to do accurate testing of
this sort, and we have seen no evidence
that would suggest that their measure-
ments are inaccurate. Nevertheless, as
we said above, we think it is important to
allow testing by more fully independent
organizations and researchers.
Since implementing this policy in March
2015, TEPCO has gradually expanded
the data it has made available, and claims
that all of its measurement data has been
available online since August 2015. It es-
timates that 70,000 items will be made
available annually. Much of this takes the
form of handwritten ledger notes which
have been scanned, and it is very time
consuming to review them. Almost all
of it is in Japanese. Nevertheless, it will
be very useful to researchers and others
to have this information available. Up to
date measurement data appears to be
available for the following categories: Wa-
ter treatment facilities; Tanks, Discharged
water /Sprinkled water; Accumulated
water/Contaminated water in the build-
ings; Units1-4 facilities/Common facili-
ties; Units 5,6 facilities; General facilities/
Whole site facilities /Others; Waste fluid/
Water used for Decontamination; Drain-
age/River; Groundwater; Soil /Gravel /
Gravel inside the Power Station; Hazard-
ous materials; Outside Power Station:
TEPCO Disclosure page (Japanese):
http://www.tepco.co.jp/decommision/
planaction/disclosure/2015/01/index-j.
html

5
English index:
http://www.tepco.co.jp/decommision/
planaction/disclosure/2015/04/images/
english_form.pdf
In addition, beginning in 2015, TEPCO
improved the accessibility of its overall
monitoring results, and has made it pos-
sible to choose reports in various catego-
ries using a calendar interface:
TEPCOMonitoringresultspage(English)
http://www.tepco.co.jp/en/nu/fukushi-
ma-np/f1/smp/index-e.html
Quite a lot of information related to the di-
saster is made available by various Japa-
nese Government agencies in download-
able form, much of it in English. These
efforts are poorly coordinated at best,
and the content is often repetitive, with
nearly identical information being pub-
lished by different agencies, though often
with minor differences which require vigi-
lance to spot. The original sources for the
information are usually cited somewhere,
and while several agencies have the offi-
cial power to conduct their own inspec-
tions, in practice information regarding
Fukushima Daiichi itself almost invariably
comes from TEPCO. In the absence of
adequate independent sources, we are
forced to rely on official documents like
these for much of the information we in-
clude in Section 2.1, about the Daiichi
site, and we attempt to highlight relevant
caveats and uncertainties. While we also
make use of official data in the sections
on evacuees, environment, food, and
health as well, much more independent
information and research data is general-
ly available for these.
Official Reports
The International Atomic Energy Agency
(IAEA) plays a major role in the global gov-
ernance of nuclear weapons and nucle-
ar energy, and its actions (and inaction)
have been key factors in the response to
the Fukushima disaster. IAEA investiga-
tion teams are given access to the Daiichi
site regularly, and also evaluate TEPCO
and government data, issuing periodic
reports on their findings. IAEA publishes
the reports it receives from TEPCO and
Japanese Gov’t ministries on its Fukushi-
ma Daiichi Status Updates page:
https://www.iaea.org/newscenter/focus/
fukushima/status-update
These reports are generally brief, read-
able summaries, and provide links to
other relevant reports. They also include
brief assessments of the information pro-
vided. One of the most recent reports
is from August 2017. Approximately 30
pages of summaries and links provided
by the government are followed by 2 1/2
pages of commentary and critique from
the IAEA:
Events and highlights on the prog-
ress related to recovery operations at
Fukushima Daiichi Nuclear Power Sta-
tion, August, 2017
https://www.iaea.org/sites/default/files/
events_and_highlights_august_2017.pdf
This is actually a useful list of reports and
findings from TEPCO and government
sources, and includes recent information
about the ocean, decontamination, food,
etc. It’s important to keep in mind that
participation in IAEA programs is volun-
tary on the part of national governments,
and though there are consequences
for non-participation and non-compli-
ance, the IAEA is given access at the
behest of the government and only with
its cooperation. The IAEA can request
access to specific sites or to specif-
ic information, but there are occasional
signs that it doesn’t always get what it
has requested. All of this must be kept
in mind when reading and parsing IAEA

6
reports, whose language is always ex-
tremely formal and diplomatic. More
reports related to the Fukushima acci-
dent are available on the IAEA’s website :
https://www.iaea.org/newscenter/focus/
fukushima
The IAEA issued its comprehensive re-
port on the Fukushima Disaster in Au-
gust, 2015:
IAEA Releases Director General’s
Report on Fukushima Daiichi Accident
https://www.iaea.org/newscenter/
news/iaea-releases-director-gener-
al%E2%80%99s-report-fukushima-daii-
chi-accident
It includes the Report by the Director
General (about 220 pages), as well as
five technical volumes, each with several
electronic annexes. The Director Gener-
al’s Report is divided into several sec-
tions:
» The accident and its assessment (how
the accident progressed, how and
where safety functions failed, contrib-
uting human factors, etc)
» Emergency preparedness and re-
sponse (initial official responses in
Japan, protective measures taken for
emergency workers and the public, in-
ternational response, etc)
» Radiological consequences (environ-
mental consequences, public expo-
sure, health effects, etc)
» Post-accident recovery (remediation
and decontamination, on-site prepa-
rations for decommissioning, commu-
nity issues, etc)
» The IAEA response to the accident
(Initial activities, action plans devel-
oped, cooperation, meetings and
conferences, etc)
» The technical volumes follow a similar
breakdown:
» Technical Volume 1/5 - Description
and Context of the Accident
» Technical Volume 2/5 - Safety Assess-
ment
» Technical Volume 3/5 - Emergency
Preparedness and Response
» Technical Volume 4/5 - Radiological
Consequences
» Technical Volume 5/5 - Post-accident
Recovery.
There are 40 downloadable files in all,
and a printed version, with CD-ROM
annexes, is also available. The Director
General’s report section is also available
in several languages, including Arabic,
Chinese, French, Russian, Spanish and
Japanese.
The report is massive, in short, and we
suspect that very few people have read
more than a portion of it. We will refer to
some of its relevant findings in Section
2.5: Health, and elsewhere, but won’t
attempt to summarize the entire report.
We will note that though it couched it in
characteristically diplomatic language,
the IAEA’s criticism of TEPCO and the
Japanese government in this report is
as scathing as we are ever likely to read
from a UN agency. It is reasonable to ask
why, of course, if the regulatory failures
and lack of preparation for accidents
were so extreme, the IAEA had not de-
tected this prior to the accident and in-
sisted that Fukushima Daiichi and other
TEPCO nuclear powerplants be shut
down until safety modifications had been
made. I think the only answer for this is
that the IAEA cannot enforce safety, can
only recommend what it considers best
practices, and that it is only given access
to what the government wants it to see.

7
We think the recognition of the huge con-
sequences of this in case of Fukushima
should by now be leading to calls for
more effective and binding governance
of nuclear energy worldwide. Such calls
may be being made, and in April 2017,
a law reforming nuclear inspections was
passed by the Japanese Diet. This law,
based on US precedent, specifically al-
lows regulators to conduct unannounced
inspections of nuclear plants and gives
them unlimited access to data they re-
quest. It will not come into effect until
2020, however, and it is unclear if it ap-
plies to international bodies like the IAEA
as well as to Japanese regulators.
KYODO: Revised law enables surprise
inspection of nuclear plants Apr. 08,
2017
https://japantoday.com/category/nation-
al/revised-law-enables-surprise-inspec-
tion-of-nuclear-plants
The 2015 IAEA report includes discus-
sion of volunteer efforts after Fukushi-
ma, and Safecast is mentioned very
positively in that context (see Tech-
nical Volume 4, Annex III, p.23):
http://www-pub.iaea.org/MTCD/Publi-
cations/PDF/AdditionalVolumes/P1710/
Pub1710-TV4-Web.pdf
While the full IAEA report was issued in
August 2015, a draft of the Report by
the Director General section was leaked
online by Greenpeace in late May of that
year:
Greenpeace website IAEA report draft
download page (Japanese):
http://www.greenpeace.org/japan/ja/
news/blog/dblog/iaeaweb/blog/53006/
Greenpeace also issued a critique of the
report based on the leaked draft:
http://www.greenpeace.org/japan/
Global/japan/pdf/IAEA analysis by GP
20150528.pdf
Interestingly, TEPCO, in its first major
progress report issued since the release
of the IAEA report, agreed with IAEA crit-
icism on all of the main points regarding
inadequate preparation, complacency,
underplaying tsunami risk, faulty safe-
ty analyses, etc.. (see p. 71 of the text
linked below). TEPCO enumerates the
measures it has put in place to address
these shortcomings, but while it may be
possible to evaluate some of of the tech-
nical aspects, we may never know which
of those those rooted in corporate and
political culture are actually being reme-
died.
Nuclear Safety Reform Plan - Progress
Report (Including Progress on Safety
Measures at Power Stations) (2nd Quar-
ter, FY2015) November 20, 2015
http://www.tepco.co.jp/en/press/
corp-com/release/betu15_e/imag-
es/151120e0102.pdf
The 2015 IAEA report follows on others
from UN agencies:
WHO Preliminary dose estimation from
the nuclear accident after the 2011
Great East Japan Earthquake and Tsu-
nami, 2012
http://www.who.int/ionizing_radiation/
pub_meet/fukushima_dose_assess-
ment/en/
WHO Health risk assessment from the
nuclear accident after the 2011 Great
East Japan earthquake and tsunami,
based on a preliminary dose estimation,
2013
http://www.who.int/ionizing_radiation/
pub_meet/fukushima_risk_assess-
ment_2013/en/

8
UNSCEAR 2013 Report to the Gener-
al Assembly, Volume I: Report to the
General Assembly, Scientific Annex A:
Levels and effects of radiation exposure
due to the nuclear accident after the
2011 great east-Japan earthquake and
tsunami, 2014
http://www.unscear.org/unscear/en/
publications/2013_1.html
A draft of the UNSCEAR report on
Fukushima was also leaked in 2013
several months prior to release. Safe-
cast made a summary critique of
the UNSCEAR Fukushima report:
http://www.slideshare.net/safecast/un-
scear-2013-fukushima-final-report-com-
mentary-v02
The German branch of the International
Physicians for the Prevention of Nuclear
War (IPPNW) issued a critique of the UN-
SCEAR report as well:
http://www.fukushima-disaster.de/filead-
min/user_upload/pdf/english/Akzente_
Unscear2014.pdf
Dr. Keith Baverstock also published a
strong critique of the UNSCEAR report,
through the Japanese magazine Kaga-
ku, focusing on structural issues within
the organization and their implications:
https://www.iwanami.co.jp/kagaku/
Kagaku_201410_Baverstock.pdf
After its 2013 report was issued, UN-
SCEAR experts continued to collect data
on the Fukushima accident, reviewing
more than 200 publications issued be-
tween October 2012 and December
2015 (the 2013 report considered infor-
mation available up to October 2012).
UNSCEAR has issued two white papers
to evaluate these new findings, one in late
2015, another in 2016. The 2015 white
paper was based on evaluation of publi-
cations available by Dec 2014. In it they
examine new evidence related to four
thematic subject areas: releases and dis-
persion for the atmosphere and marine
environment; evaluations of doses for the
public and workers; health implications
for the workers and the public; and dos-
es and effects for non-human biota. They
also directly address the critiques from
Baverstock and IPPNW, among others:
Developments Since The 2013 UN-
SCEAR Report On The Levels And Ef-
fects Of Radiation Exposure Due To The
Nuclear Accident Following The Great
East-Japan Earthquake And Tsunami,
2015
publications/Fukushima_WP2015.html
A second white paper was issued in
2016, which examined new information
available up to the end of 2015. UN-
SCEAR notes that, “In principle, the
scope of the second white paper was
extended to include not only publica-
tions in peer-reviewed journals, but
also peer-reviewed conference papers,
reports issued by regional/national in-
stitutes/organizations, government de-
partments/ministries, learned societies,
utilities, and similar bodies, 7 reports
issued by intergovernmental organiza-
tions, and major compilations (and/or
analyses) of data from official and other
sources.”
They add that, “In exceptional cases,
the scope was extended to scientific
reports issued by non-governmental or-
ganizations.” In addition to the previous
thematic areas covered, the transfer of
radionuclides in terrestrial and freshwater
environments was added as a new area
of evaluation. The authors state that par-
ticular effort was made to evaluate new
information that might challenge their pri-
or conclusions, but that while a number
of areas where not enough research has

9
been done were identified, they found
nothing which significantly affected the
main findings of the 2013 report.
Another notable recent publication from
UNSCEAR is Sources, Effects And Risks
Of Ionizing Radiation, 2016 (published in
2017). This is part of an ongoing series of
major UNSCEAR reports about radiation
hazards and impacts, and is intended
to be an authoritative scientific under-
pinning for radiation risk evaluation and
international protection standards. While
not intended to focus on Fukushima,
many questions and findings that have
emerged from this disaster are presented
in the analyses.
UNSCEAR: Sources, Effects And Risks
Of Ionizing Radiation, 2016 (Published
April 2017)
publications/2016.html
The Safecast Report, Part 2: Situation
Report consists of five separate sections
dealing with Fukushima Daiichi itself,
Evacuees, Environment and Decontam-
ination, Food, and Health. The file you
are reading contains section 2.1- Issues
at Fukushima Daiichi Nuclear Powerplant
(FDNPP). In this and the subsequent
sections, released separately, we begin
with a general summary of each topic,
followed by more in-depth discussion.
Organizational acronyms:
» JAEA: Japan Atomic Energy Agency
» IAEA: International Atomic Energy
Agency
» NIRS: National Institute of Radiological
Sciences
» NRA: (Japan) Nuclear Regulatory Au-
thority
» METI: Ministry of Economy, Trade, and
Industry
» MEXT: Ministry of Education, Culture,
Sports, Science and Technology
» IRID: International Research Institute
for Nuclear Decommissioning
Acknowledgements:
Many thanks to Andrew Pothecary, de-
signer of many of the infographics which
appear on throughout the Situation Re-
port sections. Many of these previously
appeared in the Number 1 Shimbun, the
magazine of the Foreign Correspondents’
Club of Japan (FCCJ) and are credited as
such, while others were made specifical-
ly for this report. We would also like to
thank the many researchers and special-
ists who have given us valuable feedback
on our drafts. Of course any errors are
our own.
Special thanks to Alvin Cheung for design
and layout.
Extra special thanks to Jory Felice
for his fabulous cover design.
http://www.jory.tv

10
2.1- Issues at
Fukushima
Daiichi Nuclear
Powerplant
(FDNPP)
The disaster at the Fukushima Daiichi
site is ongoing. Though many urgent is-
sues need to be addressed, it is difficult
to call it an “emergency” now. Rather,
it is a long-term crisis. Conditions on-
site appear to be stable, and cautious,
methodological approaches have been
developed and implemented for deal-
ing with the many problems. Progress is
very slow. The following sections sum-
marize the current status of decommis-
sioning, removal of spent fuel rods, wa-
ter problems, and other issues, noting
that the information comes almost en-
tirely from TEPCO and for the most part
cannot be independently confirmed.
Notable changes since last year’s
report: Updates on the overall decom-
missioning timeline; updates on prepa-
rations for removing remaining spent
fuel from the spent fuel pools; progress
on water treatment and remediation;
discussion of the tritiated water prob-
lem; update on the completion of the
frozen underground wall; update on
preparations for melted fuel debris re-
moval; updated muon imaging results;
description of progress of remote/ro-
botic investigations inside the reactors;
discussion of onsite worker issues.
2.1.1 — Decommissioning
roadmap
Briefly put, everything that is being done
now and which will be done on site un-
til the year 2020 is merely preparation
for the really hard work of removing the
hazardous highly radioactive melted
fuel debris from the bottom of the re-
actor buildings. TEPCO’s roadmap for
this has slipped more than once, though
the company seems to be basically on
schedule so far, but the work gets much
harder from this point forward. Much of
the needed technology is either untried
or does not yet exist. Regulatory over-
sight is in place, but we still don’t think it
has enough teeth. Incremental progress
was made in 2016 and 2017 on the most
challenging issues, with some important
successes regarding investigations in-
side the reactor vessels.
TEPCO released its first decommission-
ing roadmap—a timeline describing the
expected schedule of work on the clean-
up of the Daiichi site—in Dec. 2011, and
has issued periodic updates, most re-
cently in July 2017, with word of a nota-
ble revision being released in Sept. 2017.
The original 2011 plan is a complicated
document that points to the ultimate
removal of melted fuel from the reactor
containments at some as yet unknown
date in the future, demolition of the build-
ings themselves, and remediation of the
site. Much of the actual planning for later
stages of the work cannot be done un-
til success has been assured on earlier
stages, particularly in solving the many
water-related problems on the site. In
fact, some of the technologies expect-
ed to be required for actually extracting
the melted fuel do not exist yet, though
research and development is underway
and some notable technical successes
have been achieved.

D1: Site guide to the Fukushima Daiichi Nuclear Power
Plant (FDNPP), July 2017 (source: TEPCO)
D2: Long-term decommissioning diagram (source: TEP-
CO, annotations by SAFECAST)

12
TEPCO: Mid-and-long-Term Road-
map towards the Decommissioning
of Fukushima Daiichi Nuclear Power
Station Units 1-4, Dec. 21, 2011
es/111221e14.pdf
A major revision of the roadmap, which
prioritizes risk reduction over speed, was
published by the Cabinet Oﬃce in July,
2015.
Revision of the Mid-and-Long-Term
Roadmap
http://www.meti.go.jp/english/earth-
quake/nuclear/decommissioning/pd-
f/20150725_01a.pdf
Progress Status and Future Challenges
of the Mid-and-Long-Term Roadmap
toward the Decommissioning of TEP-
CO’s Fukushima Daiichi Nuclear Power
Station Units 1-4 (Outline)
quake/nuclear/decommissioning/index.
html
This NRA document from February, 2015
describes the overall strategy:
Measures for Mid-term Risk Re-
duction at TEPCO’s Fukushi-
ma Daiichi NPS (as of July 2017)
http://www.nsr.go.jp/data/000201934.
pdf
TEPCO issues periodic updates about
decommissioning plans and progress.
These documents are compiled from
many other TEPCO sources and bring
the basic information together in one
place. Confusingly, because government
input and approval is required for these
plans, the same documents are also
made available by METI and the NRA.
This version from July, 2017 describes
the current schedule:
Summary of Decommissioning and
Contaminated Water Management
July 27, 2017 (hereafter referred to as
SCDMW)
f/20170727_e.pdf
In addition, METI recently published an
English-language PR pamphlet describ-
ing the ongoing work and future plans:
Important Stories on Decommissioning:
tion, now and in the future, 2017
quake/nuclear/decommissioning/
pdf/20170927_roadmap.pdf
The overall long-term timetable is divided
into three phases [Fig. D2]:
» Phase 1 (2012–2013): This involved
stabilization and other work done prior
to the start of removing spent fuel, and
was essentially completed on time.
» Phase 2 (2014–2021): This is the cur-
rent phase, and includes the continu-
ing removal of spent fuel, and prepa-
ration for removing melted fuel debris
from the reactor containments, includ-
ing solving many water-related issues
onsite.
» Unit 1: Spent fuel removal to
start in FY2023 (originally sched-
uled to begin in FY2017)
» Unit 2: Spent fuel removal to start
in FY2023
» Unit 3: Spent fuel removal to start
in FY2018 (originally scheduled
to begin in FY2015)
» Unit 4: Spent fuel removal com-
pleted in 2014

13
» Phase 3 (2021 -?): This is the melt-
ed fuel debris removal and decom-
missioning process itself. Though the
general approach was determined in
mid-2017, currently the actual plan
for extracting it is scheduled to be de-
cided in FY2019 (pushed back from
FY2018). Despite recently announced
delays in spent fuel removal and of the
decision regarding melted fuel debris
extraction, as of Sept. 2017 the cur-
rent road map maintains the previous
FY2021 start date for the extraction of
the debris.
Many kinds of work are carried on con-
currently onsite, and TEPCO can be said
to have met its primary goal for the end
of Phase 1 and the start of Phase 2. The
more detailed timelines are frequent-
ly adjusted, as are actual work targets,
and often slip by months or years. The
2014–2021 phase is very long, and this
reﬂects the fact that many technologies
do not exist for what needs to be done,
and are requiring years of development.
The melted fuel removal and decommis-
sioning phase expected to start in 2021
currently has no estimated end point,
though TEPCO has previously stated it
would be 30–40 years from now. Based
on prior experience at Three Mile Island
and at Chernobyl (where melted fuel has
not yet started to be removed), we should
assume it will require several decades.
TEPCO does not make its plans in iso-
lation, but receives guidance and in-
structions from Japanese government
agencies and organizations such as the
METI, NRA, JAEA, NIRS, and IRID, and
is required demonstrate to the IAEA that
progress is being made onsite. As noted
above, NRA and IAEA conduct period-
ic reviews and onsite inspections, but
we feel that so far they have lacked the
manpower, if not the mandate, to con-
duct the kind of unannounced daily in-
spections that seem to be warranted. As
noted above, this may be changing. The
government seems to rely too heavily on
what TEPCO tells it, and the IAEA seems
to depend primarily on information pro-
vided by the Japanese government.
We’re left to conclude that the only entity
which really knows what’s happening on-
site is TEPCO itself, and that despite its
disclosure policy it is able to be selective
about what data it releases, how, and
when. The IAEA issued a (preliminary)
inspection report on February 17, 2015,
and its major Fukushima report in August,
2015, as described above. Documents
released by UN agencies invariably ad-
here to a careful diplomatic language
which requires a fair amount of parsing
and reading between the lines. Not sur-
prisingly, however, the IAEA reserved its
strongest criticism for TEPCO’s failures
of management and oversight. Partly be-
cause of continued problems in these ar-
eas, we assume, new corporate entities,
the Fukushima Daiichi Decontamination
and Decommissioning Engineering Com-
pany and the Nuclear Damage Compen-
sation and Decommissioning Facilitation
Corporation, were established, intend-
ed to improve oversight of these critical
long-term projects.
IAEA International Peer Review Mission
On Mid-And-Long-Term Roadmap
Towards The Decommissioning Of
TEPCO’s Fukushima Daiichi Nuclear
Power Station Units 1–4 (Third Mission)
Preliminary Summary Report To The
Government Of Japan, 9–17 February
2015
https://www.iaea.org/sites/default/ﬁles/
missionreport170215.pdf
METI provides a number of decommis-
sioning-related reports on its website:
quake/nuclear/decommissioning/index.
html

14
Contaminated Water Management July
27, 2017 (SCDMW)
f/20170727_e.pdf
The FDADA site makes a lot of relevant
information about the decommission-
ing process easily accessible. It is not
always as up to date as releases from
TEPCO or METI, however:
Website of the Information Portal for the
Fukushima Daiichi Accident Analysis and
Decommissioning Activities
https://fdada.info/
The IRID consortium (International Re-
search Institute for Nuclear Decommis-
sioning) has been developing technol-
ogies, primarily robots, for use in the
decommissioning process. A careful
look at their web site can give an idea
of the state of the technologies under
consideration and development, but one
gets the sense that they do not want to
share too much potentially proprietary in-
formation.
IRID website:
http://irid.or.jp/en/
2.1.2 — Overall conditions
According to recent TEPCO reports,
cooling water continues to be circulated
inside the reactor buildings. The tem-
peratures of the Reactor Pressure Vessel
(RPV) and Primary Containment Vessel
(PCV) of Units 1-3 were maintained with-
in the range of approx. 20-35C in recent
months. [Fig. D3]
No signiﬁcant change in the density of
radioactive materials newly released from
reactor buildings in the air was detected,
and cold shutdown conditions have been
maintained. In June 2017, the radiation
exposure dose at the Daiichi site bound-
ary from the release of radioactive mate-
rials from the Unit 1-4 reactor buildings
was determined to be less than 0.00028
mSv/year. During the same period, the
density of the radioactive materials new-
ly released from Units 1-4 in the air and
measured at 8 monitoring posts at the
Daiichi site boundary was determined to
be approximately 2.2×10-12 Bq/cm3 for
Cs-134, and 1.2×10-11 Bq/cm3 for Cs-
137. [Fig. D4]
Contaminated Water Management; July
27, 2017 (SCDMW)
f/20170727_e.pdf
As noted in the UNSCEAR 2016 White
Paper, which cites Steinhauser et al.
2015, although continuing radioactive
releases from the Daiichi site are gener-
ally low enough to require sophisticated
equipment to detect them, decommis-
sioning and dismantling activities onsite
have occasionally led to more noticeable
secondary releases even years following
the accident. Speciﬁcally, radioactive dust
has on occasion been released into the
environment when parts of the damaged
reactor buildings have been moved. The
releases described have been detectable
and in at least one case led to measur-
able contamination, but their potential
impact on health has been considered
negligible (see “Tobichitta-jikken” in Sec
2.4: Food). It is more important that what
happened in the cases known to date be
well understood and adequate measures
be implemented to prevent more serious
releases from occurring.
Steinhauser et al, Post-Accident
Sporadic Releases of Airborne Radio-
nuclides from the Fukushima Daiichi

D3: (top and bottom) Graphs of temperatures inside reactor
units 1-3, April-July 2017 (source: TEPCO)
D4: Annual radiation dose at Daiichi site boundaries from
radioactive materials (cesium) released from Reactor Building
Units 1-4 (source: TEPCO)

16
Nuclear Power Plant Site, Environ. Sci.
Technol., 2015, 49 (24), pp 14028–
14035
http://pubs.acs.org/doi/abs/10.1021/
acs.est.5b03155
2.1.3 — Spent fuel pools
TEPCO successfully removed all of the
spent fuel from Unit 4 in late 2014, but
over 1500 spent fuel rods remain atop
the damaged reactor buildings of units
1, 2, and 3. These units are proving to
be more difficult, not least because
radiation levels where workers need
to be are still too high for safety. The
schedules for removing the remaining
fuel rods has been pushed back sev-
eral times as a result. Preparations for
removing the spent fuel from Unit 3 are
far along, and the work should com-
mence within the coming year. The last
fuel pools are now due to start being
emptied by 2023. This fuel needs more
secure long-term storage than in the
common pool onsite, though no prog-
ress seems to have been made on pre-
paring a place to put it.
One of the most critical ongoing tasks
is the removal of hazardous spent fuel
assemblies from the spent fuel pools of
Units 1, 2, 3, and 4 (Unused fuel assem-
blies also need to be removed, but are
not as hazardous). The process poses
unique engineering and worker protec-
tion challenges, and serious mishaps
could have wider negative consequences
for the public and the environment. After
the success of emptying Unit 4’s spent
fuel pool in 2014, TEPCO seemed ready
to move quickly on the others, but later
decided that it was more prudent to take
the extra time necessary to prepare the
sites and technology more thoroughly in
order to reduce worker radiation doses.
This includes developing more remotely
operated systems to do the actual work.
Unit 1:
This spent fuel pool contains 392 fuel as-
semblies, and the schedule for starting
the removal of the spent fuel has been
pushed back from FY2017 to FY2023. As
was the case with Units 3 and 4, which
also suffered massive hydrogen explo-
sions, the upper level of Unit 1 is a chaot-
ic tangle of fallen structural elements and
equipment, and mounds of radioactive
rubble. Work for surveying and remov-
ing this must be done remotely for safety
reasons, and the risk of the release of ra-
dioactive dust is significant. The building
was covered for several years following
the accident by a lightweight structure
intended to contain ongoing releases of
radiation to the air. This needed to be
removed to allow the next steps of the
work to proceed. Roof and wall panels of
the building cover had been dismantled
by mid-November 2016, and the cover’s
pillars and beams were removed in May
2017. Detailed 3D scans of the condi-
tions on the operating floor have been
made and developed into digital models
that will guide subsequent work planning.
Rubble removal work has been ongoing,
but slow. The reasons given for pushing
the start of spent fuel removal back from
2020 to 2023 recently were the need to
ensure that radioactive dust was not re-
leased during the process, the challeng-
es of safely removing some of the large
fallen structural elements and equipment
that lie over the spent fuel pool itself, and
the challenges of minimizing the expo-
sure of workers onsite. [Fig. D5, D6]
Detailed TEPCO report on Unit 1 issues,
March 2017 (in Japanese)
http://www.meti.go.jp/earthquake/nu-
clear/decommissioning/committee/os-
ensuitaisakuteam/2017/03/3-02-03.pdf

D5: Unit 1 workﬂow for dismantling building
cover (source: TEPCO)
D6: Unit 1 refueling ﬂoor:
Above: 3D model showing
fallen ceiling crane and fuel
handling machine (FHM),
Right: present condition
(source: TEPCO)

18
Independent summary and discus-
sion of this document in English:
http://www.fukuleaks.org/
web/?p=16279
Unit 2:
This spent fuel pool contains 615 fuel as-
semblies, and the start of removal was
recently pushed back to 2023. Because
this reactor did not suffer a devastating
explosion like the others, the erection of
a large independent secure structure like
those at units 3 and 4 will probably not
be necessary. But because of the high
dose rates and the need for adequate
access for remotely-operated heavy
machinery, as well as space needed to
install the fuel handling equipment and
fuel removal frame, it has been decid-
ed to completely dismantle the building
above the top floor. The area around Unit
2 has been cleared for heavy machinery
access, which entailed dismantling small
buildings nearby, beginning in Septem-
ber, 2015. An enclosed workspace had
been constructed atop a large platform
alongside the refueling floor on the west-
ern side of the building, and an opening
is being made in Unit 2’s wall there to al-
low access to the operating floor. Once
the existing roof and upper walls have
been dismantled, a new structural cov-
er will be built. The decision has not yet
been made whether this will cover the
entire upper floor or only a portion of it.
In general less information is available
from TEPCO about the plans and status
of Unit 2’s spent fuel removal work than
for theother units. This may reflect the
less challenging nature of the work there
compared to the other reactor buildings,
since the operating floor appears to be
largely intact. Nevertheless more infor-
mation should be made available to the
public. [Fig . D7, D8]
Unit 3:
Preparations for removing the spent fuel
from Unit 3 are far along. After several
delays, fuel removal is currently sched-
uled to begin in 2018. Although the 566
assemblies that need to be removed
(514 used, 52 unused) are far fewer than
there were in Unit 4, the Unit 3 operating
floor level had been largely inaccessible
to workers because of high dose rates
until the completion of decontamination
and floor shielding in late 2016. As at the
other units, much of the work onsite is
being done remotely for this reason. The
removal of the fuel rods is expected to
be done primarily remotely as well. The
required equipment has been complet-
ed and tested, and workers trained in its
use.
Like at Unit 4, a large structure is being
built at Unit 3 which will house the new
fuel handling machine, crane, and oth-
er necessary equipment. As Unit 4, the
structure is designed so that it places
minimal extra load on the damaged re-
actor building. The area surrounding
Unit 3 was cleared so that an indepen-
dent supporting structure for the new
operating floor and the new cover could
be built. This takes the form of a large
horizontal cylinder, often referred to as a
“dome” (though technically speaking it is
a “cylindrical vault”). It was built in sec-
tions offsite at Onahama Bay, where the
assembly procedure was rehearsed, and
installation at Unit 3 began in July 2017.
As of Sept 2017 two of the eight sec-
tions were in place. Installation of guide
rails and other structure for the new fuel
handling machine was completed in
July 2017. Other dose-reduction mea-
sures are being implemented at Unit 3
in preparation for the fuel removal work.
The first floor was partly decontaminated
using newly developed remote machin-

ery, including machines which use blast-
ed dry-ice, and this work will continue as
the results are evaluated. [Fig. D9, D10]
TEPCO: Installation of Unit 3 spent fuel
removal cover dome roof at Fukushima
Daiichi Nuclear Power Station (Second
unit)
http://photo.tepco.co.jp/en/
date/2017/201709-e/170907-01e.html
TEPCO: Preparation of fuel remov-
al from the spent fuel pool in Unit 3
reactor building at Fukushima Daiichi
Nuclear Power Station — Demonstra-
tion of fuel handling machine and crane,
Jan 18, 2016
ma-np/handouts/2016/images/hand-
outs_160118_01-e.pdf
(This document has good diagrams and
plans of most of the aspects discussed
above, and includes a timeline)
[D7- IMAGE] Cover proposals for Unit 2 spent fuel removal: Left: Full cover,
right: Partial cover (source: TEPCO)
D8: Unit 2 large external structure at refueling ﬂoor level (source: TEPCO)

20
The current phase of work at Unit 3 is
largely construction and installation of the
required shelter and equipment, which
generally appears to be proceeding ac-
cording to plan, in a predictable fashion.
But this required several years of chal-
lenging and unpredictable cleanup and
site preparation beforehand. Removal of
rubble from the roof was completed in
Oct. 2013. The spent fuel pool was also
full of structural debris which was care-
fully mapped and modeled in 3D to help
guide the remotely controlled removal
equipment. [Fig. D11]
TEPCO, Unit 3 spent fuel pool 3d debris
maps etc, Jan 2015 (in Japanese)
http://www.meti.go.jp/earthquake/nu-
clear/ pdf/150129/150129_01_3_5_07.
pdf
There were mishaps, such as equipment
being accidentally dropped back into the
pool while it was being removed, and
highly radioactive dust was released while
a large girder was being removed from
the roof adjacent to the pool (known as
the Tobichitta jikken. See Sec 2.4: Food).
One of the most challenging tasks, the
removal of the 20-ton fuel handling ma-
chine, the largest piece of debris in the
Unit 3 spent fuel pool, was safely con-
cluded in August 2015. It required the
development of special cutting and lifting
apparatus. Similar apparatus will likely be
necessary at Unit 1.
In delicate operation, 20-ton object
removed from Fukushima fuel pool, Aug
2,2015
Removal Of Unit 3 Fuel Handling
Machine Hailed As Major Milestone In
Decommissioning Effort
The removal of the remaining large piec-
es of debris was completed in Novem-
ber, 2015. After the large debris was
removed, visual inspections inside the
pool were conducted in December to
determine the condition of the fuel as-
semblies. Six deformed assemblies had
been identified earlier, and no significant
deformities in other fuel assemblies was
detected in the December inspections.
After this, the detailed removal plan could
be devised.
Main work to help remove spent fuel at
Unit 3
https://fdada.info/currentstatus/decom-
missioning-16
Investigative results inside the Unit 3
spent fuel pool
missioning-11
As much as we think TEPCO deserves
criticism, we feel the engineering thinking
and implementation for the spent fuel re-
moval at Unit 3 deserves to be acknowl-
edged. Conditions onsite make cleanup
and site preparation risky, however. TEP-
CO and its partners appear to be taking
the lessons learned from the difficulties
they encountered at Unit 3 into consider-
ation as they develop their plans for Units
1 and 2.
Unit 4:
The removal of 1533 fuel rods from Unit
4’s spent fuel pool was successfully
completed without mishap on Dec. 22,
2014. The process necessitated remov-
ing a large quantity of rubble and dis-
mantling unnecessary upper structure,
building a very large, multistory structure
which cantilevered over the damaged
reactor building to stabilize it while not
imposing any additional load, and in-
stalling new fuel handling machinery. The
removed fuel assemblies were placed in
fuel transfer casks, 71 times in all, and

D9a: Assembly sequence for Unit 3 cover (source: TEPCO)
D9b (above left): Rendering of completed
Unit 3 cover (source: TEPCO)
D9c (above): Sectional view showing
structural relationship of Unit 3 “dome”
(grey), new supporting framework (red),
and existing Unit 3 (white) (source: TEP-
D10: (left) Unit 3 cover sections
in place, Oct. 25, 2017(updated)
(source: TEPCO)
D11: (left) 3D debris map of Unit 3
spent fuel pool (source: TEPCO)

22
trucked a short distance to the common
pool onsite at Daiichi, where it is expect-
ed to be stored for 10–20 years, and
then transferred to more secure storage
(though the decisions about how and
where remain to be made). Prior to the
commencement of this operation and
throughout there were very loud and
alarming claims from many quarters that
failure was likely and that mishaps would
lead to the extinction of the human race.
Because we had looked closely at the
seismic stability and structural damage
reports for Unit 4 beforehand, we con-
sidered these claims to be exaggerated,
and in fact, giving credit where it is due,
we have been impressed by the engi-
neering design of this particularly chal-
lenging and unprecedented project. It is
functioning as proof of concept for the
removal of spent fuel from the remaining
reactor units. [Fig. D12, D13]
Tepco info page about decommission-
ing, including PR videos:
http://www.tepco.co.jp/en/decommis-
ion/planaction/removal-e.html
2.1.4 — Water problems
The water problems we hear so much
about at the Daiichi site remain serious
and are an obstacle to starting other
decommissioning work. They also con-
tinue to pose potential consequences
for the environment and marine life, and
so need to be closely monitored. The
influx of groundwater into the site pos-
es the greatest problems, and because
it has been impossible to actually map
its underground flow, efforts to control it
have had unpredictable consequences.
These problems have forced TEPCO to
think ambitiously and innovatively, and
though none of the ideas have worked
out quickly or perfectly, they appear to
be advancing technology in some ar-
eas.
No-one really expected the water prob-
lems at Daiichi to be solved easily. Some
progress appears to be being made,
however. The continuing root cause is
that both the water which has been being
circulated through the damaged reactors
to cool the melted fuel and groundwa-
ter which has been leaking through the
site and into the buildings themselves
both become radioactively contaminat-
ed (though precisely what it is coming
into contact with and where remains un-
clear). TEPCO has implemented several
“contaminated water countermeasures,”
to deal with various facets of the overall
problem with varying degrees of success.
Their approach, which has remained un-
changed for several years, can be divid-
ed into three main components, each of
which involves several technologies:
D12: Fuel removal structure at Unit 4 (source:
TEPCO)
D13: Diagram showing relation of new
structure to damaged Unit 4 (source:

23
1. To effectively filter the cooling water
which is being recirculated to re-
move radionuclides.
2. To prevent groundwater from com-
ing into contact with radioactive ma-
terials.
3. To prevent contaminated water from
leaking out into the environment.
TEPCO claims to be making progress in
all these areas, and the IAEA still reserv-
edly acknowledges this. As noted above,
more independent confirmation of radi-
ation levels in the water onsite has be-
come available. But there’s still a lot we
don’t know.
The overall scale of the problem may be
best illustrated by the number of water
tanks needed to store the radioactive
water. TEPCO estimates that roughly
600 m3 of groundwater is flowing into
the area surrounding Daiichi Units 1, 2,
3, and 4 per day, and that about 140 m3
of this finds its way into the reactor build-
ings. As of July 2017, there were over
1,100 massive water tanks onsite for
storing water in various stages of treat-
ment, with more being constructed. The
first tanks used were 374 hastily-con-
structed bolted-flange types which had
a propensity to leak. Since May 2015
these have been being dismantled and
replaced with more secure welded tanks.
Asahi: PHOTO: More than 1,100 water
storage tanks at Fukushima plant ... and
counting
Dismantling of flange tanks completed in
H1 east area
missioning-2
Storage of Contaminated Water/Treated
Water (Increase in Number of Tanks)
missioning-2
Dismantling of flange tanks completed in
H1 east area
missioning-2
Storage of Contaminated Water/Treated
Water (Increase in Number of Tanks)
missioning-2
Situation of Storage and Treatment of
Accumulated Water including Highly
Concentrated Radioactive Materials at
tion (321st Release) Sept 25, 2017
es/170925e0101.pdf
A fairly good peer-reviewed paper de-
scribing the groundwater contamination
situation onsite was published in 2016
(paywalled). It includes a good descrip-
tion of the underlying geology and how
this affects the water flow:
The aftermath of the Fukushima nuclear
accident: Measures to contain ground-
water contamination; Gallardoa and
Maruib, Science of The Total Environ-
ment, Volume 547, 15 March 2016,
Pages 261–268
http://www.sciencedirect.com/science/
article/pii/S0048969715312845
Other recent papers have estimated the
amount of radionuclides being released
into the ocean due to the continued leak-
age of contaminated groundwater, in
context with the extremely large releases
from Daiichi in March-April of 2011, as
well as compared to other accidents and
events. We will touch on this in Sec 2.2:
Environment.

24
2.1.4.a — Radionuclide re-
moval systems
TEPCO has spliced together several
different systems for removing radionu-
clides from water onsite. These started
as an unreliable hack, but have gradu-
ally grown and become more reliable,
and a modular approach has made it
possible to scale up and add new ca-
pabilities. While breakdowns and poor
performance were frequently noted in
earlier years, the technology seems to
be one of the few major elements of the
overall water strategy that is working
well now. The inability of these systems
to remove tritium, however, together
with the lack of space to build more
storage tanks, means that a difficult
political decision will need to be made
soon about releasing it into the ocean.
TEPCO continues to use several water
treatment systems—ALPS, SARRY, and
Kurion—to remove radionuclides from
the recirculating water. First, contami-
nated water from the reactor buildings is
processed by two adsorption systems,
SARRY (Simplified Active water Retrieval
and RecoverY system) and Kurion (the
name of the manufacturer), to reduce the
levels of cesium and strontium. Then it is
desalinated. After this, some of the water
is recirculated to cool the reactors, and
the rest sent to the Multi-nuclide Remov-
al Facility. This system, the largest water
processing system onsite, is designed to
remove 62 nuclides, and includes three
subsystems which are variants of ALPS
(Advanced Liquid Processing System).
The processed water is sent to storage
tanks. All of these systems have been
steadily upgraded, and TEPCO claims
that with the exception of tritium, radio-
nuclides in the finally processed water
are below or near the detection limit. In
January 2015, TEPCO reported that the
multi-nuclide removal system has been
processing approximately 1,260 tons of
water per day, while the other systems
have been processing approximately 800
tons per day. This has enabled TEPCO to
treat previously stored water as well as
newly recirculated water. In May 2017,
TEPCO announced that it had complet-
ed the purification treatment, including
strontium removal, of the highly con-
taminated water in the storage tanks.
Water which is pumped into the reactor
buildings for cooling eventually finds its
way to the basements of the reactors
and connected buildings, where it mixes
with groundwater inflow, and is eventual-
ly pumped out to be recirculated again.
TEPCO counts this basement water as
storage, and the level is kept fairly con-
stant. It is currently at approximately
50,000 tons in total. [Fig. D14, D15]
TEPCO: Update on the com-
pletion of contaminated wa-
ter treatment, January 23, 2015
TEPCO: target nuclides to be removed
[does not include target levels!]
ion/planaction/images/150517.pdf
Situation of Storage and Treatment of
Accumulated Water including Highly
Concentrated Radioactive Materials at
tion (321st Release) Sept 25, 2017
es/170925e0101.pdf
TEPCO Contaminated Water Treatment
Info page: (includes system diagrams,
maps of what is stored where, and how
water storage has changed over time)
ion/planaction/alps/index-e.html

D14 (above): Water treatment
ﬂow diagram (source: TEPCO)
D15 (left) Graph of hanges in
stored water quantities, July
2016- July 2017 (source:
TEPCO)

26
Information Portal for the Fukushima
Daiichi Accident Analysis and Decom-
missioning Activities:
Progress Report: Contaminated water
countermeasures
missioning-16#p4
The nuclide removal process generates
highly contaminated waste products,
primarily sludge from the adsorption sys-
tems, as well as waste fluid. These are
transferred to high-integrity containers
(HIC) and stored onsite. As of February
2017, there were approximately 3,519 of
these containers being stored.
FDADA: Management status of second-
ary waste from water treatment
https://fdada.info/en/home2/decom-
missioning2/progress2/decommission-
ing-16-en/
2.1.4b Tritiated Water Prob-
lems
The treated water, however, still con-
tains tritium (H3) at well above allowable
levels. This has led to a host of tech-
nical and political problems. Tritium is
considered by the expert community to
pose a fairly low health risk compared to
radionuclides like strontium or cesium.
Its allowable levels for drinking water or
discharge into the environment are ap-
proximately ten-thousand times higher
than for Cs-134, for instance — 60,000
Bq/L for Tritium vs 60Bq/L for Cs-134.
But it is wrong to conclude that it pos-
es no risk whatsoever, and no credible
scientist would make that claim. On the
contrary, a number of expert “dissent-
ers” from the consensus viewpoint say
that the risks from tritium exposure may
be well underestimated.
TEPCO has spent years building trust
with the local fishermen’s cooperative
“JF Zengyoren,” and by including them in
planning and acceding to their conditions
for third-party water testing and other as-
surances, has gained their agreement
regarding the release of water pumped
from less-contaminated “bypass” and
“subdrain” wells. Discussions regarding
what to do about the tritiated water have
been continuing for years, and TEPCO
seemed optimistic that some agreement
could eventually be reached despite con-
tinued opposition from the fishermen.
Both the IAEA and the NRA have repeat-
edly recommended that TEPCO conduct
a controlled release of the tritiated water,
saying that if it were done carefully there
would be minimal impact to the environ-
ment. TEPCO has repeatedly resisted
the idea, however, being unwilling to do
so without the clear agreement from the
local fishermen. Then suddenly, in July of
2017, Tokyo Electric Power Co. Holdings
new chairman Takashi Kawamura said at
a press conference that the decision to
release the tritiated water to the ocean
had already been made. A predictably
loud public outcry ensued, and even
TEPCO staff were caught unprepared.
In the days following, TEPCO issued
statements which backtracked from
Kawamura’s, but the damage to TEP-
CO’s agreements with the cooperatives
and to the reputation of the fisheries had
been done. They are now back to square
one. In addition, much of the global pub-
lic assumes this water is already being
dumped.
Japan Times: Fukushima fishermen fight
release of tainted water as tritium stand-
off continues, March 19, 2017
https://www.japantimes.co.jp/
news/2017/03/19/national/fukushi-
ma-fishermen-fight-release-tainted-wa-
ter-tritium-standoff-continues/

27
Japan Times: Fukushima’s tritiated wa-
ter to be dumped into sea, Tepco chief
says, July 14, 2017
https://www.japantimes.co.jp/
news/2017/07/14/national/
science-health/tepco-says-de-
cision-already-made-release-ra-
dioactive-low-toxic-tritium-sea-fisher-
men-irate/#.WdCPHjOB3GI
Newsweek: Fukushima’s Nuclear Waste
Will Be Dumped Into The Ocean, Japa-
nese Plant Owner Says 7/14/17
http://www.newsweek.com/fukushi-
ma-nuclear-waste-dumped-ocean-japa-
nese-protests-637108
WSJ : Fukushima Watch: Regulator
Calls on Tepco to Discharge Tritium
Water, Jan 21, 2015
http://blogs.wsj.com/japanreal-
time/2015/01/21/fukushima-watch-reg-
ulator-calls-on-tepco-to-discharge-tri-
tium-water/
The actual concentrations of tritium in
the water stored onsite at Daiichi are
assumed to vary from between approx
0.5 to 4.2 million Bq/L. This means that
it would need to be diluted between 8
and 75-fold in order to reach the legally
allowed concentration of 60,000 Bq/L.
Diluting it would not reduce the total ra-
dioactivity released, however. In the case
of less-contaminated water pumped up
from the Daiichi site and released with
the agreement of local fishermen, TEP-
CO allowed third-party testers to con-
firm that any tritium was below TEPCO’s
own operational target of 1500 Bq/L. If
it were to commit to the same opera-
tional target for the tritiated water, then
perhaps agreement is not out of reach.
In 2013, TEPCO formed a Tritiated Water
Taskforce comprised of specialists from
government and academia, civil society
representatives, and industry (including
TEPCO itself). This taskforce evaluated
11 options for dealing with the tritiated
water, looking at five treatment methods
combined with different pre-treatments.
The options it evaluated included: geo-
logical injection, discharge into the
ocean, atmospheric emission as vapor,
atmospheric emission as hydrogen gas,
and underground storage. For reasons of
time, safety, and cost, ocean discharge
was considered the least objectionable
option. The group estimated that off-
shore release would take 4-6 years.
Tritiated water taskforce report June
2016
f/20160915_01a.pdf
Isotopic separation was examined by the
task force as a potential pre-treatment for
release to the ocean or atmosphere. This
technology got a fair amount of atten-
tion in the press in 2015-2016, and the
Kurion company received a large devel-
opment contract in 2015. The company
said at the time that it had demonstrated
the effectiveness of its system, and could
begin processing tritium-contaminated
water at Daiichi as soon as mid-2017.
Such a system would be extremely ex-
pensive, however.
Kurion Building a Prototype Modular
Detritiation System Sept 8, 2015
http://kurion.com/kurion-building-a-pro-
totype-modular-detritiation-system/
Kurion Modular Detritiation System
http://kurion.org/wp-content/up-
loads/2014/11/MDS-Brochure-for-WEB.
pdf
Bloomberg: How Kurion Plans to Clean
Up Fukushima’s Tritium Nuclear Waste,
Feb 6, 2016
http://www.bloomberg.com/news/
articles/2016-02-04/how-kurion-plans-

28
to-clean-up-fukushima-s-tritium-nuclear-
waste
2.1.4.c — Groundwater prob-
lems
Unless the flow of groundwater into
the reactor building basements is con-
trolled, it won’t be possible to carry out
the next steps to prepare for removing
the melted fuel debris. The solution im-
plemented so far is an ambitious series
of underground dams made of frozen
soil, and dozens of pumps. All of the
work is complicated by the radioactivity
of the water and the site itself. The fro-
zen wall has been activated, and TEP-
CO believes that it is effective in partial-
ly reducing the water inflow.
According to most sources, before any
measures were put in place, approx-
imately 300 m3 of groundwater was
entering the reactor buildings per day.
Since implementing countermeasures,
TEPCO believes this has been reduced
to 140 m3/day. The problem is rooted in
the initial siting of the building. Though
the ground level where the building sits
was originally much higher, major ex-
cavation was done to lower the site in
order to make the pumping of cooling
water from the ocean easier, bringing the
buildings into contact with the permeable
geological layers through which ground-
water flows. Under normal conditions the
buildings had an adequate seal against
this water, as well as efficient “subdrain”
pumps to remove it, but since the 2011
disaster large amounts of water have
been entering the reactors, apparently
through cracks or other openings under-
ground. Exactly how and where remains
a mystery. Several methods of dealing
with this water are being tried with mixed
success so far. [Fig. D16]
TEPCO: Current Status of groundwater
inflow countermeasures (in Japanese),
Aug 30 2017
http://www.tepco.co.jp/nu/fukushi-
ma-np/handouts/2017/images2/hand-
outs_170830_03-j.pdf
Sealing the buildings
Sealing any below ground-level openings
in the reactor buildings would seem to
be the best and most direct option for
keeping groundwater out, and efforts are
being made to identify where the leaks
are and to develop sealing methods. But
the radiation levels inside and next to the
reactor buildings are generally too high
to allow humans to work safely for any
length of time. In fact, radiation in many
parts of the buildings is high enough to
give lethal exposures within a short time
(over 5000 mSv/hr in Unit 1, 4400 mSv/
hr or over in Units 2 and 3, with a high-
ly publicized spot reading of 9.4 Sv/hr in
Unit 2). Techniques for repairing cracks
and other gaps remotely are being inves-
tigated, and are expected to be required
in order to prepare the structures for the
removal of melted fuel after 2021, but
they do not currently exist. No significant
progress has been reported on these ef-
forts since last year. [Fig. D17]
Groundwater Bypass
Because the groundwater is flowing into
the site from the mountains on the side
opposite the ocean, it has been hoped
that intercepting as much of this water as
possible before it reaches the site could
greatly reduce the amount reaching the
reactor buildings. Groundwater on the
uphill mountain side so far has not shown
high levels of radioactive contamination,
so after an agreement was reached with
Japan Fisheries Cooperatives to have it
stored and independently tested before
being released to the ocean—the first
agreement of this sort reached—the
pumping and diversion of the water was

29
begun in April 2014. As of July 25, 2017,
296,991 m3 of groundwater has been
pumped up and released. The IAEA es-
timated that this has reduced ground-
water ingress by approximately 25%,
not as much as was hoped, but an im-
provement nonetheless. The bypass wa-
ter is tested by third parties once every
ten days. TEPCO’s operational targets
for radionuclides in this water are 1 Bq/L
for Cs134 and Cs137, 3 Bq/L for gross
beta, and 1500 Bq/L for H3 (tritium). All
of these are far below Japanese limits as
well as WHO drinking water standards.
Recent results show that levels much
lower than TEPCO’s targets have been
achieved.
Detailed analysis results regarding the
water quality of the groundwater being
pumped out for by-passing at Fukushi-
ma Daiichi Nuclear Power Station,
September 1, 2017
f/20170901_01a.pdf
Bypass water sampling at southern
outlet, Sept 9, 2017 (Japanese)
ma-np/f1/smp/2017/images3/pump_
well_17090902-j.pdf
Subdrains
A system of about 40 drain pumps, called
“subdrains,” located near the reactor and
turbine buildings, existed prior to the ac-
cident. These were intended to mitigate
potential problems from groundwater
during normal operation of the plant, but
were seriously damaged and have been
unusable since March 2011. This system
has been repaired. Tests were conduct-
ed in 2014, and since September 2015,
about 360 m3 per day of water has been
pumped up and processed. After being
puriﬁed and stored in tanks, like the water
from the groundwater bypass, it is sub-
ject to third-party monitoring conditions
and the approval of the Japan Fisheries
Cooperatives before it is released to the
ocean. A total of 371,383 m3 has been
released as of July 25, 2017. Since the
full-scale operation of the frozen earth
wall commenced, TEPCO believes that
in combination with subdrain operation it
is able to adequately control the ground-
water levels around the reactor buildings.
TEPCO: Groundwater pump-up by
Subdrain or Groundwater drain
ion/planaction/sub-drain/index-e.html
D16: Schematic sectional view of the Daiichi site showing relationship of groundwater levels, under-
ground ice wall (“land-side impermeable wall”), pumps, etc. (source: TEPCO)

30
Subdrain water test results, (Japanese)
Sept 23, 2017
ma-np/f1/smp/2017/images3/subsur-
face_170923-j.pdf
English guide:
ma-np/f1/smp/2016/images/weight-
ed_average_form-e.pdf
Detailed analysis results regarding
the water quality of the groundwater
pumped up by sub-drain and purified
at Fukushima Daiichi Nuclear Power
Station, Sept. 1, 2017
f/20170901_01b.pdf
TEPCO releases first batch of decon-
taminated Fukushima groundwater to
sea, September 14, 2015
In addition to the 41 subdrains near the
reactor buildings, five additional ground-
water drains were dug near the sea side
impermeable wall (see below). Filtering
and releasing this water was begun in
November 2015. However, the water
proved to be too highly contaminated
with tritium to meet the discharge criteria,
and in January 2016 TEPCO announced
that it would be stored instead. The high
tritium levels maybe due to contact with
highly contaminated soil near the sea-
wall. Closure of the seawall also raised
groundwater levels behind it significantly,
requiring more water to be pumped than
planned.
Fukushima Daiichi NPS Prompt Report
(Jan 08,2016) Recent Topics:Tepco
Stores Rather Than Discharges From
Groundwater Drain After Monitoring
Detects Higher Contamination Levels
D17 (right): Plan showing lo-
cations of high doserates in
Unit 3, 1Fl, as of Feb. 2015.
Areas indicted in red are over
50 mSv/hr. (source: TEPCO)

31
Asahi Shimbun: TEPCO confronts new
problem of radioactive water at Fukushi-
ma plant, Dec 26, 2015
Since the closing of the frozen earth wall,
the quantity of water pumped up via the
subdrains has been strongly affected by
rainfall. TEPCO says that the treatment
capacity for the subdrain water is being
incrementally increased to accommo-
date the growing volume of pumped-up
groundwater during the high rainfall sea-
son. UNSCEAR 2016 notes the connec-
tion between periods of increased rainfall
and sporadic increases of Cs137 levels
in the ocean near Daiichi:
“The general decrease of the direct re-
leases to the ocean has been confirmed
by the continuous monitoring at the out-
lets of FDNPS. However, this monitor-
ing has also shown sporadic increases
of 137Cs levels as a result of exchanges
of water between the harbour and the
ocean. Most of these sporadic increas-
es correspond to heavy rainfall events.
Hirose has concluded that there are two
main pathways by which radionuclides
are continuing to be discharged into the
ocean. One is a continuous release due
to exchange of waters between the har-
bour and the open ocean, and the other
is a sporadic discharge of contaminated
water via drainage because of rainfall.”
p9
Frozen underground wall
After examining several alternatives,
TEPCO decided upon a controversial
plan to construct a 30 meter-deep wall,
or dam, of frozen earth around the reac-
tor buildings in hopes that this will pro-
vide an effective barrier to water ingress.
The structure, called the “land-side im-
permeable wall,” forms a rectangle ap-
proximately 500m by 200m, with a total
perimeter of about 1500m. Though the
frozen earth technique is well-proven and
is often used in very challenging mining
and tunneling operations, the wall at Daii-
chi is the longest ever actually attempted,
and is being done with an ever-present
radiation hazard as well as many under-
ground obstacles. Onsite tests began in
August 2013, construction began in June
2014, and freezing tests were begun in
April 2015. Construction of the system
was completed in October, 2015. Freez-
ing was started on the sea side and part
of the mountain side from March 2016,
and on 95% of the mountain side from
June 2016. The wall is currently about
99% frozen. [Fig. D18]
TEPCO Website: Land-side Imperme-
able Wall (Frozen Soil Wall)
https://www4.tepco.co.jp/en/decommi-
sion/planaction/landwardwall/index-e.
html
Land-side impermeable walls
missioning-15
TEPCO : Recent Topics: Fukushima-
Installation Of Facilities Required For
‘Ice Wall’ Construction Is Complete,Feb
09,2016
http://www.tepco.co.jp/en/decommi-
sion/planaction/landwardwall/index-e.
html

32
General description of the frozen wall
system with diagrams.
TEPCO: Information on frozen wall test-
ing, May 21, 2015:
TEPCO’s data indicates that the frozen
wall has greatly reduced the water inflow,
but much about the plan remains unpre-
dictable. There are many interconnected
and constantly fluctuating variables. In
order to prevent more contaminated wa-
ter from leaking out of the reactor build-
ings and finding its way to the ocean, it is
necessary to keep the water level in the
basements of the reactor buildings be-
low the level of the groundwater in the
surrounding areas. For this reason, the
groundwater level must be decreased
gradually and carefully monitored and
controlled. TEPCO seems to think it will
be possible to contain any leakage within
the perimeter of the frozen wall, and has
been pumping water in and out to main-
tain the proper levels. The closure of the
seaside impermeable wall in September
2015 led to unpredictable fluctuations
of groundwater levels there, and similar
unpredictability may occur with the fro-
zen wall. Partly for this reason, the Japan
NRA called for caution and a long testing
period to confirm the effects, and initial-
ly only gave approval for the portion on
the ocean-side of the reactors, as well
as several “control” segments on the
mountain-side, to be fully frozen. Obtain-
ing NRA approval at each stage, TEPCO
was able to freeze almost all of the re-
mainder by August 2017. Together, the
delays put the frozen wall about a year
behind schedule. [Fig. D19]
TEPCO evaluates the effectiveness of
the frozen earth wall by measuring the
difference of the groundwater level on
the inside of the wall compared with the
outside on both the mountainside and
seaside (through direct measurement at
wells), the amount of groundwater flow-
ing into the reactor buildings (by direct
measurement of the amount they pump
in and out compared to the levels they
measure inside), and the amount of in-
flowing groundwater from the mountain
side (estimated by totaling the measured
pumping amounts and subtracting rain-
fall). They consider the sharp decrease
in the amount of water that needs to be
pumped out from the wells between the
reactor buildings and the seawall to be a
major indicator of the effectiveness of the
frozen wall.
The Aug 30, 2017 TEPCO document
linked below (in Japanese) details their
findings [Fig. D20]:
» F: Groundwater inflow from the moun-
tain side (estimate): March 2016 : 760
m3/day > July 2017 600 m3/day
(F is estimated by totaling the mea-
sured pumping amounts and sub-
tracting rainfall)
» A: Volume pumped from subdrains
(measured): March 2016 : 390 m3/day
> July 2017 500 m3/day
» B: Building inflow (estimated from
actual measurements): March 2016 :
170 m3/day > July 2017 140 m3/day
» C: Groundwater amount pumped to
“4m deck” between reactor buildings
and seawall (estimated from actual
measurements): March 2016 : 250
m3/day > July 2017 120 m3/day
(Even after rains they’re pumping less
here)
» D: Amount leaking from beyond the
frozen wall, i.e. deep underground:
March 2016 : 0 m3/day > July 2017

D18: Schematic showing the placement of the
underground ice walls. (source: TEPCO)
D19: Diagram illustrating how un-
derground water levels will need to
be careful controlled to prevent the
outflow of highly contaminated water
from the damaged buildings int the
surrounding ground (Source: Asahi
Shimbun)
D20: Diagram showing analysis of the effectivness of the frozen wall based on com-
plex water flow (see text for explanation) (source: TEPCO)

34
0 m3/day (assumed)
» E1: Rainfall recharge (estimated from
actual measurements): March 2016 :
20 m3/day > July 2017 150 m3/day
» E2: Groundwater level fluctuation
(generally negative): March 2016 : -30
m3/day > July 2017 -10 m3/day
TEPCO: Current Status of groundwater
inflow countermeasures (in Japanese),
Aug 30 2017
This 2016 TEPCO report explained the
frozen underground wall plan in detail:
TEPCO: Study results of the land-side
impervious wall, Feb 15, 2016
Also available at:
http://www.nsr.go.jp/data/000139731.
pdf
TEPCO: Progress of Landside Imper-
meable Wall freezing: the Second Stage
Feb 9, 2017
TEPCO: Phase 3 freezing of Landside
Impermeable Wall starts at Fukushima
Daiichi Nuclear Power Station, Aug 22,
2017
User “Sotan” posted a detailed English
summary of this document on the Phys-
ics Forums online discussion:
https://www.physicsforums.com/
threads/japan-earthquake-nucle-
ar-plants-part-2.711577/page-
41#post-5378915
Sankei Shimbun: Japan NRC calls for
reconsideration of seaside frozen wall
(Japanese), Jan. 22, 2016
http://www.sankei.com/affairs/
news/150322/afr1503220003-n1.html
Asahi Shimbun: NRA to allow part of
frozen soil wall at Fukushima plant, Feb.
15, 2016
Asahi Shimbun: NRA calls a halt to TEP-
CO’s plan to freeze soil at Fukushima
plant, Feb 10, 2016
Asahi Shimbun: TEPCO nears ‘deep
freeze’ of soil wall at Fukushima plant,
Feb. 21, 2016
Sea-side impermeable wall
Groundwater samples taken from ob-
servation wells in the area between the
reactor buildings and the ocean front (in-
take and port areas) have in the past reg-
ularly shown high levels of radionuclides,
particularly gross beta (which includes
strontium) but also cesium. In Oct. 2014,
samples from one set of wells showed
over 7.8 million Bq/L gross beta, which
declined to 500,000 Bq/L by Jan. 2015.
Tests from March 2016 showed gross
beta of up to 600,000 Bq/L, Cs-137 up
to 36,000 Bq/L, and tritium up to 63,000
Bq/L. Although the total radiation levels
are many thousands of times lower than
they were in March and April, 2011, this
degree of contaminated water has con-
tinued to seep into the ocean, contam-

35
inating and recontaminating the seabed
offshore (see Part 2.3: Environment and
Decontamination). To stop this seepage,
TEPCO constructed a 30m deep wall of
sheet pilings called the “sea-side imper-
meable wall” along the ocean frontage of
the site, about 780m in total length. It
was completed in Oct. 2015. [Fig. D21]
Impermeable seaside wall closure —
Sept 2015
As noted above, closing this wall caused
groundwater levels behind it to rise. The
increased pressure caused deflection in
the wall and a gap to open between it
and the ground. The wall was reinforced,
repairs being completed in early Decem-
ber 2015.
missioning-16
Based on testing of seawater outside of
the wall, the seaside impermeable wall
seems to have been effective in reduc-
ing the amount of contaminated water
reaching the ocean. Testing data from
mid-December 2015 showed the levels
of strontium and gross beta there had
dropped to close to the detection limit
when the wall was fully closed in October
2015, and stayed low through mid-De-
cember that year.
On Sept 29, 2017, TEPCO’s port water
test results showed that Cs-137 was de-
tected at low concentrations (0.49- 1.2
Bq/L) at 7 of the 8 sample points, and
was undetected at the other. Tritium,
maximum levels of 3.7 Bq/L, was detect-
ed at 4 of the 8 points, and gross beta
was detected at 4 sample points, maxi-
mum levels of 18 Bq/L. Cs-134 was un-
detected. Water in the inner port (intake
channel) was moderately higher, with Cs
137 detected at all 4 sample points, with
a maximum of 6.8 Bq/L ; tritium at all 4
sample points up to 21 Bq/L, and gross
beta at 2 sample points, with up to 28
Bq/L. All of these indicate that the sea-
side impermeable wall is fairly effective:
D21: Schematic plan and section showing the placement of the sea-side
impermeable wall, underground layers, and the ocean. (source: TEPCO)

36
TEPCO: 2. Analysis Results of Seawater
Obtained around Fukushima Daiichi NPS
(Inside of the Port of Fukushi-
ma Daiichi NPS), Sept 29, 2017
ma-np/f1/smp/2017/images/intake_ca-
nal_map-e.pdf
TEPCO: Analysis Results of Seawater
Obtained around Fukushima Daiichi NPS
September 29, 2017 (Inside of Unit 1-4
Water Intake Channel), Sept 29, 2017
ma-np/f1/smp/2017/images/2tb-east_
map-e.pdf
Fukushima Daiichi wall seems effective
as seawater pollution drops: TEPCO 6
November 2015
http://www.fukushimaminponews.com/
news.html?id=590
A graph on the summary progress
report from Feb. 09 2016 showed con-
tinued low levels of Sr90, beta, etc thru
12/12/2015
es/160209e0101.pdf
TEPCO regularly releases test data for
water taken from the port area as well as
from offshore (see Section 2.3.3—The
Ocean), but we feel that not all relevant
locations are covered, and reiterate that
without independent confirmation some
skepticism remains about the accuracy
of the figures TEPCO provides.
TEPCO: Monitoring by sampling- Re-
sults of Radioactive Analysis around
Fukushima Daiichi Nuclear Power
Station, index page to measurements
onsite and immediately offshore:
ma-np/f1/smp/index-e.html
Trenches
Each of the reactor turbine buildings is
connected to seawater intake pumps
and other equipment at the waterfront
by interconnected underground tun-
nels called trenches, for seawater piping
and power cables primarily, as well as a
number of connecting shafts and smaller
underground structures. The trenches of
Units 2 and 3 in particular became filled
with several thousand tons of highly con-
taminated water during the early phase
of the disaster, and due to continuing
leaks and poorly-understood flow mech-
anisms, appeared to contain a mixture of
contaminated cooling water and ground-
water. As we reported in previous years,
several early attempts to remove it by us-
ing freezing and other techniques failed,
but significant progress was made in late
2014 and afterward. Water in the seawa-
ter piping trench of Unit 1 is relatively low
in contamination, so no removal opera-
tions are planned. Sealing and filling the
trenches at Unit 2 was completed on July
10, 2015. Contaminated water transfer
from Unit 3 was completed on July 30,
and the trench shaft filled and sealed by
August 27. Work at Unit 4 was done in
two stages, and completed on Dec. 21,
2015. TEPCO says that closing these
routes for contaminated water leakage
at Unit 3, for instance, has reduced the
total radioactivity of the water accumu-
lated in the trenches and turbine build-
ings to 1/10 of its previous level, and has
significantly decreased the risk of highly
contaminated water reaching the ocean.
There have been no significant devel-
opments regarding the trenches since
then. [Fig. D22]
TEPCO: Seawater Piping Trench (as of
July 30, 2015)
ion/planaction/trench/index-e.html

Removal of contaminated water and
ﬁlling of Unit 4 seawater pipe trench
complete
https://fdada.info/currentstatus/de-
commissioning-11
2.1.5 — Melted fuel removal
The process of removing the melted
fuel debris from inside the reactors
will require decades, and the most
optimistic scenarios have it starting in
2021. The last time something simi-
lar was attempted was over 25 years
ago, at Three Mile Island, where melt-
ed core removal was completed in
1990 (it has not yet been attempted
at Chernobyl). Consequently there are
not many people with relevant experi-
ence to call on for assistance. A new,
well-funded research institute has
been established to incubate the kinds
of technologies that will be necessary.
Meanwhile many systematic attempts
at surveying conditions inside the re-
actor pressure vessels remotely have
been made, with increasing success.
Removing melted fuel debris from in-
side the damaged reactors and storing
it safely is the primary goal of the de-
commissioning process. As mentioned
above, this is not scheduled to actually
start until around 2021, and everything
that has been done onsite until now and
which will be done until the actual re-
moval process begins is preparation for
that stage. Because of the tremendous
technical challenges involved, which ex-
ceed the experience and know-how of
any existing single company, the Inter-
national Research Institute for Nuclear
Decommissioning (IRID) was estab-
lished in 2013. This consortium is un-
der the guidance of the Japan Atomic
Energy Agency and the National Insti-
tute of Advanced Industrial Science and
Technology, and includes as founding
members major corporations such as
Toshiba, Hitachi-GE Nuclear Energy,
Ltd., and Mitsubishi Heavy Industries,
Ltd., as well as major electric utilities
from around the nation. IRID’s primary
mission is to research and develop the
necessary technologies for decommis-
D22: Plan of underground trenches at Units 2 and 3 (source: TEPCO)

38
sioning the nuclear reactors, which it
seeks to do in cooperation with compa-
nies and organizations both inside and
outside of Japan. IRID has been very ac-
tive, seeking and funding proposals and
organizing meetings and workshops,
some of which have had tangible results,
particularly in robotics. [Fig. D23]
Two primary scenarios for extracting the
melted fuel debris have been under con-
sideration. The so-called “submersion” or
“flooding” method was considered the
current front-running idea until recently.
This method, derived in part from that
used at Three Mile Island, would involve
plugging leaks in the reactor contain-
ment so it can be filled with water, and
then using remote-controlled machinery
inserted from above on long telescoping
arms to cut up and extract the melted
fuel in pieces. The water would provide
good radiation shielding and therefore a
good margin of safety for workers. But
after a series of insufficiently promising
experiments to develop methods to plug
cracks and openings in the reactors to
prevent the radioactive water from leak-
ing, it was judged too difficult. In August
2017 the Nuclear Damage Compensa-
tion and Decommissioning Facilitation
Corporation (NDF) announced that the
“dry” or “side entry” method had been
selected for further development and
implementation instead. [Fig. D24, D25,
D26]
Mainichi: New proposal suggests
removing Fukushima plant’s melted nu-
clear fuel from side, Aug 1, 2017:
https://mainichi.jp/english/arti-
cles/20170801/p2a/00m/0na/014000c
This presentation from April. 2015 gives
an overall explanation of IRID’s plans that
have been under consideration:
R&D activities related to the fuel debris
retrieval from the Fukushima Daiichi
NPS, April 9, 2015
http://irid.or.jp/_pdf/20150409.pdf
Also:
http://www-pub.iaea.org/iaeameetings/
cn235p/Session5/S5-4-Takashi-Satoh.
pdf
The following video from May 2014 ex-
plains the submersion method (uses
Flash):
IRID: Explanatory video for Submersion
Method for Fuel Debris Retrieval, May
2014
http://irid.or.jp/en/video/
Under the “dry removal” scenario, a long
robotic arm would be inserted into the re-
actor vessels from the side, and the de-
bris would be shaved off gradually with
drills and/or lasers. Though the method
is called “dry,” all indication is that the
melted debris would remain covered with
water (“partial submersion”), but the re-
moval process itself would require mov-
ing the radioactive material through the
open air, while water is poured remotely
to suppress radioactive dust.
This detailed 2016 report from NDF de-
scribes the removal scenarios and the
results of planning and testing in great
detail:
NDF: Technical Strategic Plan 2016 for
Decommissioning of the Fukushima
Daiichi Nuclear Power Station of Tokyo
Electric Power Company Holdings, Inc.,
July 13, 2016
http://www.dd.ndf.go.jp/en/strate-
gic-plan/book/20170322_SP2016eFT.
pdf
The 2017 NDF Technical Strategic Plan
(Japanese only available so far) was re-

39
leased on August 31, 2017, after the de-
cision to use the side entry method was
announced:
東京電力ホールディングス(株)福島第一
原子力発電所の廃炉のための技術戦略
プラン 2017
http://www.dd.ndf.go.jp/jp/strate-
gic-plan/book/20170831_SP2017FT.pdf
Before this can be done, the melted
fuel debris must be located, the reactor
buildings decontaminated and shielded
so that workers can enter, power and
communications re-established inside
the buildings, and methods developed
to minimize the further spread of con-
tamination during the decommissioning
process. Progress has been made in all
of these areas. Meanwhile, though some
initial progress has been made, most of
the robotic equipment necessary to sur-
vey inside the torus rooms and lower
levels of the containment buildings is still
being developed and tested. This is nec-
essary both to identify places that need
repair to stop leaks, and also to precisely
locate the melted fuel itself. The sobering
reality is that the technology for dealing
with many of the tasks that melted fuel
removal will entail does not yet exist.
In March, 2015, Naohiro Masuda, the
former manager of the Fukushima Daini
NPP, who successfully prevented a melt-
down there in March 2011, and who is
now TEPCO’s manager in charge of de-
commissioning Daiichi, gave a very can-
did interview to NHK television. In it he
spoke frankly about the challenges and
uncertainties surrounding the decom-
missioning eﬀort, highlighting many of
the same issues discussed in the 2015
version of this report. He said, in part:
“We have no idea about the debris,
we don’t know its shape or strength.
We have to remove it remotely from
30 meters above. But we don’t have
that kind of technology yet. It simply
doesn’t exist….It’s a very big chal-
lenge. Honestly speaking, I cannot
say it’s possible but I also do not
wish to say it’s impossible.”
Although anyone who had been follow-
ing the plans and developments closely
D23: Initially proposed debris extraction methods (source: NDF)

D24: Proposed robot arm for use in side entry debris extraction (source: NDF)
D25: Sequence of insertion of robot arm, site preparation, and debris extraction (source: NDF)
D26: Removal and transfer of debris to storage in side entry method
(source: NDF)

41
at that point should not have been sur-
prised to hear this, these statements
were a shock to much of the wider public,
who felt they had been lulled into thinking
the process was already technically more
fully developed and under control.
NHK: Nuclear Watch: Decommissioning
Chief Opens up, March 31, 2015
http://www3.nhk.or.jp/nhkworld/english/
news/nuclearwatch/20150331.html
In Feb. 2016, NRA commissioner Toyoshi
Fuketa stressed that plans for dealing
with the fuel debris were still being for-
mulated, and removing all of it may take
too much time — 70 or 80 years — and
so might not ultimately prove to be the
best course of action. Other options, like
“removing as much fuel debris as pos-
sible and solidifying the rest,” should be
considered, he said. We have heard no
real follow up on this idea, as IRID, NDF,
and others have announced plans that
seem to assume complete removal, but
the statement highlights the unsettled
state of planning for this important step.
Japan Times: NRA commissioner
suggests plan to remove all fuel debris
at Fukushima plant may not be best
option, Feb. 20, 2016
http://www.japantimes.co.jp/
news/2016/02/20/national/nra-commis-
sioner-suggests-plan-remove-fuel-de-
bris-fukushima-plant-may-not-best-op-
tion/#.Vs6dHJN96gQ
Much of the work being done at the Daii-
chi site that relates directly to removing
the melted fuel debris involves surveys of
various kinds to locate the fuel itself and
ascertain the conditions inside the reac-
tor containments. Since 2015 advanced
imaging techniques using muons and
remotely-controlled explorations inside
the reactor vessels have been used with
increasing success.
This presentation shows the estimated
distribution of fuel debris in Unit 1, 2, and
3 based on many sources of information:
TEPCO/IRID/IAE: Estimation of current
status inside RPV and PCV at Fukushi-
ma daiichi NPS [aka ECS], July 3, 2017
http://ndf-forum.com/ref/d2_mizoka-
mi_en.pdf
2.1.5a MUON IMAGING
Muons are subatomic particles that are
created when cosmic rays pass through
the Earth’s upper atmosphere. Muon to-
mography is a method which measures
the number and trajectory of muons after
they have passed through objects. Be-
cause nuclear materials are denser than
other metals and concrete, their location
can be identified using this technology,
much like an X-Ray. After meeting with
considerable success in tests, muon
tomography has been used for locat-
ing melted fuel inside the reactors. The
detectors are left in place for months to
gradually build up an increasingly detailed
image. A team led by the High Energy
Accelerator Research Organization (KEK)
has to date produced informative imag-
es from Unit 1 in 2015, Unit 2 in 2016,
and Unit 3 in 2017. A team from Nagoya
Univ. using a different implementation of
the technology obtained useful images
of Unit 2 in 2014. In all cases, the re-
searchers concluded that little or no fuel
remained in its original locations. Difficul-
ty in placing the detectors so that good
images of the bottom of the reactor pres-
sure vessels (RPVs) could be obtained
leaves uncertainty about how much
melted fuel, if any, remains inside them.
The conditions in each of the three reac-
tors is different, but in each case careful
estimates indicate that some of the fuel
remains at the bottom of the RPV, and
the rest fell through to the concrete base-
pad below. [Fig. D27, D28, D29]

D28 (left): Muon scan image of the interior of Unit 1
pressure vessel, March 2015. (source: TEPCO)
D27 (top): Diagram showing placement of muon
scan detector plates to be used at Unit 2. (source:
TEPCO/IRID)
D29: Muon scan images of Unit 2 by Nagoya Univ. in 2014
(source: Nagoya Univ.)

Safecast Report2017: Part 2.1-Issues-at-Fukushima-Daiichi-final

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