2. NUCLEAR?
Even though the diameter
of the nucleus is in the
range
of 1.75 fm (1.75×10−15 m)
for hydrogen to
about 15 fm for the
heaviest atoms, such
as uranium, it has a
complex chemistry
behind it.
3. NUCLEAR FUEL CYCLE
The chemistry associated with any part of the nuclear fuel cycle including nuclear reprocessing.
The fuel cycle includes:
Mining
Ore Processing
Fuel Enrichment
‘In Pile’ Behavior(Use of fuel in reactor)
Back End
6. REPROCESSING OF FISSION
PRODUCTS
Reprocessing is removal of fissionable materials from products obtained from fission reactions.
PUREX CHEMISTRY
UREX CHEMISTRY
TRUEX CHEMISTRY
DIAMEX CHEMISTRY
SANEX CHEMISTRY
7. PUREX
“Plutonium URanium EXtraction”
PUREX is an acronym standing for Plutonium - URanium Extractionstandard aqueous nuclear reprocessing method for the recovery of
uranium and plutonium from used nuclear fuel. It is based on liquidliquid extraction ion-exchange.
Invented by Herbert H. Anderson and Larned B. Asprey.
Solvent Extraction Process for Plutonium and Uranium.
Major reactant – TRIBUTYLPHOSPHATE
9. Dissolution in nitric acid
Addition of 7M nitric acid to irradiated fuel
Plutonium , Uranium and other soluble elements dissolve
Insoluble mass is removed as it affects further reactions by
making emulsion stable
10. Addition of tributyl phosphate
It is done to extract uranium and plutonium from rest of the mass.
An organic solvent composed of 30% tributyl phosphate (TBP) in
a hydrocarbon solvent, such as kerosene, is added .
It extracts Uranium as UO2((NO3)2·2TBP complexes, and plutonium as
similar complexes, from other fission products, which remain in the aqueous
phase .
The transuranium elements americium and curium also remain in the aqueous
phase.
12. Treating with ferrous sulphamate
It is done to separate uranium and plutonium
Ferrous sulphamate in organic solvent, such as kerosene, is added
Plutonium reduces from +4 to +3 oxidation state and it passes into
aqueous phase
Uranium is separated through back extraction
Ferrous sulfamate Fe(NH2SO3)2
13. OTHER PROCESS
URanium EXtraction (UREX)
TRansUranium EXtraction (TRUEX)
DIAMide EXtraction (DIAMEX)
Selective ActiNide EXtraction (SANEX)
14. KEY POINTS
Liquid–liquid extraction, also known as solvent extraction and partitioning, is a
method to separate compounds based on their relative solubilities in two
different immiscible liquids, usually water and an organic solvent. It is
an extraction of a substance from one liquid phase into another liquid phase
Back Extraction is a process where in equilibrium of the reaction is made to shift
backward by decreasing the concentration of reactants.
16. FUSION- „Small to Big‟
The process of combining two lighter nuclei into a stable heavier
nucleus with liberation of energy
“Producing power from fusion here on Earth is much more
challenging than in the sun.”
17. Fusion reactor
Fusion reactor is an arrangement where in fusion of nuclei takes place with the
release large amount of energy .
“Earthbound reactors cannot achieve the high pressures of the sun’s
interior”, but this fact may be proved wrong after 10 years.
Many experiments have been executed , but none were fruitful.
18. ITER (International Thermonuclear
Experimental Reactor)
This is a major demonstration of
fusion’s potential which will soon
be built in southern France.
Designed to reach a power level of
500 megawatts, ITER will be the
first fusion experiment to produce
long pulse of energy release on a
significant scale.
Fuels used : Deuterium, Tritium
Equipment used : Magnetic
confinement method in a device
known as a Tokamak.
19. DEUTERIUM and TRITIUM: Main
Sources
Seeing the word deuterium ,everyone assumes it to be complicated
, but many don't know that it is even present in water( in small
quantity).
Duetrium can be obtained through water electrolysis.
Heavy water = Deuterium oxide D2O=2H2O
Tritium, on the other hand, is radioactive and is extremely scarce in
nature. That’s where lithium comes in. Simple nuclear reactions can
convert lithium into the tritium
20. Electrolysis of Deuterium Oxide
Electrode : Platinum
Electrolyte : D2O( Acidified heavy water)
Anodic reaction:
20 -2
Cathodic reaction: 4D+ + 4eNet reaction:
4D++ O22-
O 2+4e2D2
D2+ O2
24. Different fuel cycles
D-D fuel cycle
Though more difficult to facilitate than the deuterium-tritium reaction, fusion can also be achieved through the reaction of deuterium
with itself. This reaction has two branches that occur with nearly equal probability:
D+D →T
D+D →
3He
+
1H
+n
25. 3He
D-
fuel cycle
A second-generation approach to controlled fusion power involves
combining helium-3 (3He) and deuterium (2H). This reaction
produces a helium-4 nucleus (4He) and a high-energy proton
3He
+2H
4He
26. 11B
p-
fuel cycle
If aneutronic fusion is the goal, then the most promising candidate
may be the Hydrogen-1 (proton)/boron reaction:
Proton fuses with boron-11 ,to produces helium-4
1H
+ 11B → 3 4He
27. Will fusion energy be safe?
It is difficult to get the fusion reaction going in the first place that it
can be quickly stopped by eliminating the injection of fuel , but
engineers know how to control the first generation of fusion
plasmas.
Waste produced from this process is less radioactive and less
harmful
28. References
Girard, J.P., et al. 2007. ITER, safety and licensing. Fusion Engineering and Design 82(5-14): 506510. DOI: 10.1016/j.fusengdes.2007.03.017.
Holtkamp, N. 2007. An overview of the ITER project. Fusion Engineering and Design 82(5-14):
427-434. DOI: 10.1016/j.fusengdes.2007.03.029.
Magaud, P., G. Marbach, and I. Cook. 2004. Nuclear Fusion Reactors. Pp. 365-381 in
Encyclopedia of Energy, Volume 4, ed. C.J. Cleveland. Elsevier Science: Oxford, U.K. DOI:
10.1016/B0-12-176480-X/00305-3.
Wikipedia:
Link-http://en.wikipedia.org/wiki/PUREX
29. Thank You
Santosh M Naik 1RV12CV057 Roll no-21
Vinayaka B M 1RV12CV061 Roll no-24
F Section 2nd Sem
RVCE