This presentation covers loading pattern generation, safety calculations, operational calculations, and thermal hydraulics analysis for a nuclear reactor reload design. The objectives are to develop an acceptable core loading pattern, perform safety and operational calculations on the design including thermal hydraulics, and provide reports. Calculation methods include the ANC advanced nodal code and Westinghouse safety analysis checklist. Key parameters like cycle length, power peaking factors, reactivity coefficients, and control rod worth are analyzed.
5. Terminal Objective
j
• Become familiar with codes and methods used to
generate core loading patterns and perform reload
design analysis
d i l i
Enabling Objectives
Enabling Objectives
• Develop an acceptable reload core loading pattern
• Perform safety and operational calculations on the
Perform safety and operational calculations on the
designed LP along with thermal‐hydraulics analysis
• Provide an oral presentation and a written report
7. APA H code set used due to hexagonal geometry
APA‐H code set used due to hexagonal geometry
and consists of:
• ALPHA‐H
• PHOENIX‐H
• ANC H
ANC‐H
These codes are the same in function as square
geometry codes but modified to use hexagonal
geometry.
8. Differences from square geometry versions:
Differences from square geometry versions:
• Both the assembly and the core are modeled
in 1/6 and full core geometry
in 1/6 and full core geometry
• ANC‐H uses only one node per assembly as
compared to four nodes per assembly in ANC
d f d bl i ANC
Inputs and outputs are virtually the same
10. • Inlet core temperature varies from 533.5 °F to
et co e te pe atu e a es o 533.5 to
553.1 °F from 0% to 100% power
• Full Power Axial Offset (AO) band is ± 5%
• Control rods vary from 0 to 175 steps withdrawn
( )
• Rod Insertion Limits (RILs) are a function of core
power
• Westinghouse ZrB2 integral fuel burnable
absorbers (IFBA) are used. Possible configurations
are 0, 18, 24, 30, 36, and 48 rods per assembly.
25. MTC change in core reactivity due to a change in
MTC – change in core reactivity due to a change in
moderator temperature (fuel temperature is held
constant) and is checked at HZP for all burnup steps.
constant) and is checked at HZP for all burnup steps
A portion of the input from 03_anch_B1C4_depl.job is:
32. Since most reactors are permitted to operate
Since most reactors are permitted to operate
at full power with some control rods inserted
in the core, FΔH must also be checked with
i h l b h k d ih
allowable control rods inserted. For this
particular scenario, the calculation was
performed with the lead control bank at its RIL.
performed with the lead control bank at its RIL
44. Requirement BOC Worth (pcm) EOC Worth (pcm)
Control Banks
Power Defect 1943.7 3152.6
Void Effects 50 50
(1) Total Control Bank Requirement
(1) Total Control Bank Requirement 1993.7
1993 7 3202.6
3202 6
Control Rod Worth (HZP)
All rods inserted less most
6867 7677.3
reactive rod stuck out
(2) Less 10% 6180.3 6909.6
Shutdown Margin
Calculated Margin (2) – (1) 4186.6 3707
Required Shutdown Margin 1300 1300
45. Purpose: Simulate the unlikely event of a single
p y g
control rod being ejected from the core due to
failure in the control rod pressure housing. Total
peaking factor, F and %Δρ must be below limit
peaking factor FQ , and %Δρ must be below limit
for each condition.
Evaluated at Four Conditions:
1. BOC HFP
2. EOC HFP
3. BOC HZP
4. EOC HZP
56. Several Calculations must be performed before
Several Calculations must be performed before
the reactor can go back online after an outage:
• BOC HZP Rodworths
OC d h
• Xenon Reactivity after Startup and Trip
• Differential Boron Worth
• Isothermal Temperature Coefficient
Isothermal Temperature Coefficient
• BOC HZP Critical Boron Concentration
57. Rodworths of control banks are determined
of control banks are determined
using the boron dilution method.
Input sample from rodworth.job
E SUM edit from rodworth.0981.out
E‐SUM edit from rodworth.0981.out
58. Control Bank Worth Overview
Control Banks Inserted CBC [ppm] Bank No. Bank Worth [ppm]
ARO 1872 ‐‐‐‐‐‐‐‐‐‐‐‐ ‐‐‐‐‐‐‐‐‐‐‐‐‐
10 1796 10 76
10 + 9
10 + 9 1656 9 140
10 + 9 + 8 1563 8 93
10 + 9 + 8 + 7 1480 7 83
62. 0 0
500
‐500 ‐500
500
BOC Full Power MOC Full Power
‐1000 ‐1000
ty [pcm]
Reactivity [pcm]
BOC Half Power MOC Half Power
1500
‐1500 ‐1500
1500
Reactivit
‐2000 ‐2000
2500
‐2500 ‐2500
2500
‐3000 ‐3000
0 20 40 60 80 100 120 0 20 40 60 80 100 120
Time [hr]
Time [hr] Time [hr]
Time [hr]
Reactivity after Startup
63. 0
‐500
EOC Full Power
‐1000
EOC Half Power
Reactivity [pcm]
‐1500
‐2000
‐2500
‐3000
0 20 40 60 80 100 120
Time [hr]
Reactivity after Startup
64. 0 0
‐500 ‐500
‐1000 ‐1000
‐1500 ‐1500
Reactivity [pcm]
Reactivity [pcm]
‐2000 ‐2000
‐2500 ‐2500
‐3000 ‐3000
MOC Full Power
BOC Full Power
‐3500 ‐3500
MOC Half Power
BOC Half Power
BOC Half Power
‐4000 ‐4000
‐4500 ‐4500
0 20 40 60 80 100 120 0 20 40 60 80 100 120
Time [hr]
Time [hr] Time [hr]
Time [hr]
Reactivity after Trip
65. 0
‐500
‐1000
‐1500
pcm]
‐2000
Reactivity [p
‐2500
‐3000
EOC Full Power
‐3500
EOC Half Power
‐4000
‐4500
‐5000
0 20 40 60 80 100 120
Time [hr]
Reactivity after Trip
66. Necessary to understand the
Necessary to understand the
reactivity effect of boron in the
core under various conditions.
d i di i
Obtained by varying the boron
concentration by ± 25 ppm
throughout cycle.
throughout cycle
Input sample from dbw_HFP.job
75. Objective: perform realistic and conservative
Objective: perform realistic and conservative
calculations to determine the departure from
nuclear boiling (DNBR) at full power and the
nuclear boiling (DNBR) at full power and the
power level at which a boiling crisis occurs.
Analysis performed using the COBRA‐IV PC code
for the hot typical cell and the hot thimble cell
76. • Applies numerical solutions to determine
Applies numerical solutions to determine
thermal‐hydraulic parameters using
subchannel analysis method
subchannel analysis method
• Capable of determining flow and enthalpy
distribution at various axial and radial
distribution at various axial and radial
locations
• U
Uses the Homogeneous Equilibrium Model
h H E ilib i M d l
(HEM)
77. COBRA IV used to calculate:
COBRA‐IV used to calculate:
• fuel, clad, and coolant temperature
distributions
• flow quality and void fraction distributions
• pressure drop
• inter‐channel crossflow
78. • Calculated as a function of elevation
Calculated as a function of elevation
• Typical and thimble cells calculated with
i l d hi bl ll l l d ih
nominal and overpower cases directly
compared d
79. Mass Flux for Hot Typical Channel
3.05
3
2.95
2.9
x (Mlb/hr/ft2)
2.85
2.8
Mass Flux
2.75
2.7
Nominal Case
2.65
Overpower Case
Overpower Case
2.6
2.55
0 20 40 60 80 100 120 140
Axial Location (in)
Axial Location (in)
80. Mass Flux for Hot Thimble Channel
3
2.8
2.6
x (Mlb/hr/ft2)
2.4
Mass Flux
2.2
2
Nominal Case
Overpower Case
1.8
1.6
0 20 40 60 80 100 120 140 160
Axial Location (in)
Axial Location (in)
82. Hot Typical Cell Nominal Hot Typical Cell Overpower
Temperatures Temperatures
750 750
Coolant Temperature Coolant Temperature
Cladding Temperature
Cladding Temperature
700 700
erature (F)
Temperature (F)
650 650
Tempe
600 600
550
550
0 50 100 150
0 50 100 150
Axial Location (in)
Axial Location (in)
83. Hot Thimble Cell Nominal Hot Typical Cell Overpower
Temperatures Temperatures
750
Coolant Temperature 750
Coolant Temperature
Cladding Temperature
Cladding Temperature
700 700
erature (F)
Temperature (F)
650 650
Tempe
600 600
550 550
0 50 100 150 0 50 100 150
Axial Location (in) Axial Location (in)
84. Since the onset of nucleate boiling can be
Since the onset of nucleate boiling can be
problematic for reactor kinetics, quality and
void fraction are evaluated.
id f i l d
Void Fraction: percentage of volume in a
p y p
channel occupied by vapor
88. Minimum DNBR (MDNBR) limit is 1.17.
Minimum DNBR (MDNBR) limit is 1 17
Power was increased to determine at what
i d d i h
overpower the limit was reached
Power MDNBR Rod Channel Axial Location (in.) Cell Type
100% 3.37 2 2 107.2 Thimble
153% 1.174 11 31 135.8 Typical
89. Typical Cell DNBR
25
20
Nominal Case
Nominal Case
Overpower Case
Boiling Crisis
15
DNBR
D
10
5
0
0 20 40 60 80 100 120 140
Axial Location (in)
Axial Location (in)
90. Thimble Cell DNBR
25
20
Nominal Case
Nominal Case
Overpower Case
Boiling Crisis
15
DNBR
D
10
5
0
0 20 40 60 80 100 120 140
Axial Location (in)
Axial Location (in)