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Attachment 3, Global Nuclear Fuel - Americas, LLC, MCNP01A, Low Enriched UO2 Pin Lattice in Water Critical Benchmark Evaluations Using ENDF/B-V Nuclear Cross-Section Data, Revision 1
	ML102170185
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Site:	Nine Mile Point
Issue date:	06/30/2010
From:	; Global Nuclear Fuel - Americas
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	eDRF 0000-0032-0996, Rev 0, eDRF Section 0000-0032-0998, Rev 1 0000-0032-0998-R2
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ATTACHMENT 3 GLOBAL NUCLEAR FUEL - AMERICAS LLC MCNP01A LOW ENRICHED U02 PIN LATTICE IN WATER CRITICAL BENCHMARK EVALUATIONS USING ENDF/B-V NUCLEAR CROSS-SECTION DATA, REVISION 1 (NON-PROPRIETARY)

Nine Mile Point Nuclear Station, LLC July 30, 2010

Global Nuclear Fuel A Joint Venture of GE,Toshiba, & Hitachi 0000-0032-0998-R2 eDRF: 0000-0032-0996 Rev.0 eDRF Section: 0000-0032-0998 Rev. 1 Class I June 2010 MCNP01A Low Enriched U0 2 Pin Lattice in Water Critical Benchmark Evaluations Using ENDF/B-V Nuclear Cross-Section Data Revision 1

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 NON-PROPRIETARY NOTICE This is a non-proprietary version of the document MCNPO1A Low Enriched U0 2 Pin Lattice in Water Critical Benchmark Evaluations Using ENDF/B-V Nuclear Cross-Section Data Revision 1, from which the proprietary information has been removed.

Portions of the document that have been removed are identified by white space within double square brackets, as shown here (( )).

IMPORTANT NOTICE REGARDING CONTENTS OF THIS REPORT Please read carefully The design, engineering, and other information contained in this document is furnished for the purpose of supporting submittal of NMP2 Extended Power Uprate as stated in the transmittal letter. The only undertakings of GNF with respect to information in this document are contained in the contracts between GNF and its customers or participating utilities, and nothing contained in this document shall be construed as changing that contract. The use of this information by anyone for any purpose other than that for which it is intended is not authorized; and with respect to any unauthorized use, GNF-A makes no representation or warranty, and assumes no liability as to the completeness, accuracy, or usefulness of the information contained in this document.

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Table of Contents

1. Introduction .................................................................................................. 5

2. Critical Experiment Descriptions ................................................................ 6 2.1. LEU-COMP-THERM-001 ............................................... ............................ 6 2.2. LEU-COMP-THERM-002 ............................................................................................................. 10 2.3. LEU-COMP-THERM-006 ............................................................................................................. 14 2.4. LEU-COMP-THERM-009 ............................................................................................................. 17 2.5. LEU-COMP-THERM-016 ............................................................................................................. 24 2.6. LEU-COMP-THERM-034 ............................................................................................................. 30 2.7. LEU-COMP-THERM-039 ............................................................................................................. 35 2.8. LEU-COMP-THERM-062 ............................................................................................................. 39 2.9. LEU-COMP-THERM-065 ............................................................................................................. 45 2.10. Jersey Central Criticals with and without Poison Curtains .............................................. 50 2.11. Small Core Criticals with Burnable Absorbers (KRITZ-75) .............................................. 53 2.12. NCA Step II & III Criticals ....................................................................................................... 56 2.13. NCA G NF1 C riticals .................................................................................................................... 62

3. MCNP and the Monte Carlo Method ........................................................... 65

4. Monte Carlo Simulation Results ................................................................ 66 4.1. LEU-COMP-THERM-001 Results ......................................................................................... 68 4.2. LEU-COMP-THERM-002 Results ........................................................................................... 69 4.3. LEU-COMP-THERM-006 Results ........................................................................................... 70 4.4. LEU-COMP-THERM-009 Results ........................................................................................... 71 4.5. LEU-COMP-THERM-016 Results ......................................................................................... 72 4.6. LEU-COMP-THERM-034 Results ......................................................................................... 73 4.7. LEU-COMP-THERM-039 Results ........................................................................................... 74 4.8. LEU-COMP-THERM-062 Results ......................................................................................... 75 4.9. LEU-COMP-THERM-065 Results ......................................................................................... 76 4.10. Jersey Central Criticals with and without Poison Curtains .............................................. 77 4.11. Small Core Criticals with Burnable Absorbers (KRITZ-75) .............................................. 78 iii

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 4.12. NCA Step II & Step III Criticals ............................................................................................. 79 4.13. NCA GNF1 Criticals .................................................................................................................... 80

5. Statistical Analysis of Results .................................................................. 93 5.1. MCNPOIA Results as an Individual Population Sample .................................................. 93 5.2. MCNP01A Eigenvalues Correlated to W/F Ratio ............................................................... 95 5.3. MCNP01A Eigenvalues for Absorber Plate Sytems ......................................................... 96 5.4. MCNPOIA Eigenvalues for Gadolinium Systems .............................................................. 99

6. Bias and Bias Uncertainty ............................................................................ 102

7. Conclusions/Recom mendations ................................................................. 103

8. References ..................................................................................................... 105 Appendix: MCNP01A Benchm ark Results .......................................................... 107 iv

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1

1. Introduction This document describes one hundred-ninety (190) Light Water Reactor (LWR) critical benchmark experiment evaluations performed with the Los Alamos Monte Carlo transport code MCNP4A (Referencel). All experiments were low-enriched (5%

235U or less) U02 pin lattice in water experiments. Fifty-two of the experiments contained U02 rods with Gadolinium burnable absorber (Gd203) while seventy-seven contained other (non-fuel) structural materials such as stainless steel, Boral, borated steel and aluminum commonly found in spent fuel storage racks. All 190 experiments had material and geometric properties similar to BWR fuel lattices (not including fission product inventories) and are used to benchmark and validate the application of MCNP for both spent fuel criticality safety analyses and BWR lattice physics predictions. In addition, several include comparisons of MCNP to measured axial and radial fission density distributions.

The GE proprietary version (Reference 2) of MCNP4A (called MCNP01A) run on the GNFA cluster network was used with ENDF/B-V point-wise continuous energy cross-sections. A majority (127) of the experiments used in this report are taken from the International Criticality Safety Benchmark Evaluation Project (ICSBEP) handbook (Reference 3). Not all the experiments described in the handbook are used in this report since some lacked direct applicability to BWR spent fuel lattices. These benchmark experiments chosen represent the best available, internationally accepted, benchmark evaluations currently available for use in performing criticality safety benchmark validations for low-enriched pin-lattice in water experiments with W/F ratios between 0.8 and 4.2. ((

] None of these experiments involve the characterization of fuel lattices with actual spent fuel isotopics (i.e., fission products, actinides) since, at the time of this report, none were available.

Page 5

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1

2. Critical Experiment Descriptions 2.1. LEU-COMP-THERM-001 This series of eight extrapolated critical experiments involving lattices composed of U(2.35%)0 2 pins in a large water tank performed (Figure 2-1) at the Pacific Northwest Laboratory (PNL) in the late 1970's. These experiments included three (3) rectangular clusters of pins arranged on a square pitch of 2.032 cm and are described in detail in References 4-6.

I-ngure z-1.

PNL Critical Mass Laboratory Experimental Water Tank Page 6

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 The fuel pins used in the experiments were 1.1176 cm in diameter and 91.44 cm in active length clad in 6061 Aluminum with an OD of 1.27 cm and a wall thickness of 0.0762 cm. Figure 2-2 provides a schematic picture of the fuel rod.

FuI opeifinlions: PAS% anrlr.had UO.

Fuel rods

1. Rod dimensions Fuol CGtdIng 0.44 iW.T3& 0.500 in. OD(1.2" a)

Top -d plug (L. I 1TO Cm) 0.000 in. wall (0.O?(*cn)

S.,-,,end plug (1.27 GM)

2. n .0 In, t (91.44 cm )

( .0c )in m

107.71) ci

2. Claddding 8061 Atuninutm tubing aeal vmtde-d with a lower end plug of 5052-1-H32 Aluminum and a top plug of 1100 Aluminum.

0. Total weight of loaded fuel rods: 01? g (average)

Fuel loading 1, Fuel mbdure vl&l0rl1onaliy 0ompacted.

2 825 got UOU powderro(d, 725g ot Ulrod, 17.08 got U-235/rod,

3. Enrichment - 2.35 = 0.05 w/o U-235.

4. Fuel density - 9.20 g/cmW {84% lheoreticsl density).

Figure 2-2.

U(2.35%)0 2 Fuel Rod Different arrangements of pin clusters (19x16, 20x14, 20x15, 20x16, 20x17, 20x18, 22x16 and 24x15) were constructed. Then the separation distance between the clusters was reduced until a critical configuration was extrapolated. Since all fuel pins were of similar composition and size and all lattices were arranged on a 2.032cm square pitch, the effective water-to-fuel (W/F) ratio for these experiments was determined to be -3. This makes them suitable for benchmarking BWR reactor lattice configurations.

Page 7

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Figure 2-3 provides a schematic description of all eight benchmark experiments showing the relative pin-lattice arrangements and water separation distances for each experiment.

A Y ;

Xx Y=of rods Case 1: . . .. .-- nL

-- -----=-------- : O -O, XXY'---" AAe°'A _*T....

20 x 18.08 Case 2:

20 x 17 11.92cm 20 x 17 k- 11.92c 20 x17 Case 3:

20x6 ,--8.41 crn.-o-E,2016.,1-.41 c-O-EI 01 Case 4:

x , 10.05 C 20:, 16 10.05 C Case 5:

ED 0639 cm C01

.39 CM-0 IZ Case 6:

Case 7:

pq 4.46 cm I,,1 *o 4,46 cm 9d Case 8:

Figure 2-3.

LEU-COMP-THERM-O01 Experiments Page 8

GNF Non-proprietary Information - Class, I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Table 2-1 provides the material atom densities used for each case. This information was taken directly from Table 9 of Reference 4 with no modification.

Table 2-1. Fuel Rod Atom Densities for LEU-COMP-THERM-001 Atom Density Material Isotope Wt.% (barn-cm)_1 U(2.35)0 2 fuel U-234 0.0137 2.8563 x 10-6 U-235 2.35 4.8785 x 10-4 U-236 0.0171 3.5348 x 10. 6 U-238 97.62 2.0009 x 10-2 0 - 4.1202 x 102 1100 Aluminum Al 99.0 5.9660 x 10-2 (top end plug; 2.70 g/cm3) Cu 0.12 3.0705 x 10.5 Mn 0.025 7.3991 x 10F-Zn 0.05 1.2433 x 10-5 Si 0.4025 2.3302 x 104 Fe 0.4025 1.1719 x 10.4 5052 Aluminum Al 96.65 5.8028 x 10-2 (lower end plug; 2.69 g/cm3) Cr 0.25 7.7888 x 10-5 Cu 0.05 1.2746- 10-5 Mg 2.5 1.6663 x 10-3 Mn 0.05 1.4743 x 105 Zn 0.05 1.2387 x 10-5 Si 0.225 1.2978 x 10-4 Fe 0.225 6.5265 x 10-5 6061 Aluminum Al 97.325 5.8433 x 10-2 (clad; 2.69 g/cm3) Cr 0.2 6.2310 x 10-5 Cu 0.25 6.3731 x 10.5 Mg 1.0 6.6651 x 10-4 Mn 0.075 2.2115 x 10-5 Ti 0.075 2.5375 x 10-5 Zn 0.125 3.0967 x 10- 5 Si 0.6 3.4607 x 10-4 Fe 0.35 1.0152 x 10-4 Page 9

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 2.2. LEU-COMP-THERM-002 This series of five extrapolated critical experiments involving lattices composed of U(4.31%)0 2 pins in a large water tank performed at the Pacific Northwest Laboratory (PNL) in the late 1970's (Refs. 4-6). These experiments involved both individual and multiple (3) rectangular clusters of pins arranged on a square pitch of 2.54 cm and are similar to those performed and documented in LEU-COMP-THERM-001.

The fuel pins used in the experiments were 1.265 cm in diameter and 91.44 cm in active length clad in 6061 Aluminum with an OD of 1.415 cm and a wall thickness of 0.066 cm. Figure 2-4 provides a schematic picture of the fuel rod.

Fuel Cladding i.2M5 0.003 cm diameler 1.415 a 0.003 cm ODx 0.06Gcm wall Rtubber and cap Rubber end cap 1.278 em 0 D x poll= 1.278* cm OD 2.54 cm long F 2 254 cm long 9S." cin (1110)

.52m 0.3 c m ia-Figure 2-4.

U(4.31%)0 2 Fuel Rod Different arrangements of pin clusters were constructed for both individual and multiple cluster configurations. Then the separation distance between the clusters was reduced until a critical configuration was extrapolated. Since all fuel pins were of similar composition and size and all lattices were arranged on a 2.54 cm square pitch, the effective water-to-fuel (W/F) ratio for these experiments was determined to be -1.9. This makes them suitable for benchmarking BWR reactor lattice configurations.

Page 10

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPO1A CriticalBenchmark Evaluations - Revision 1 Figure 2-5 provides a schematic description of all five benchmark experiments showing the relative pin-lattice arrangements and water separation distances for each experiment.

A Xx Y=#of rods Y:

Case 1: **** 2.54 CM~

- - eT XxY=10x 11,51 **A: *: .46c Case 2: Case 3:

9 x 13.35 E8x 16.37 Case 4:

Case 5:

7.11 c 10 7.11 c _OE Figure 2-5.

LEU-COMP-THERM-002 Experiments Because the critical configuration was determined by extrapolation, the critical number of rods was not an integral number (as seen in cases 2 and 3).

Tables 2-2 and 2-3 provide the material atom densities used for each case. This data was taken directly from Tables 8 and 9 of Reference 5 with no modification.

Page 11

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPO1A CriticalBenchmark Evaluations - Revision 1 Table 2-2. Fuel Rod Atom Densities for LEU-COMP-THERM-002 Material Isotope Atom Density Material__Isotope_(barn-cm)_l 6

U-234 5.1835 x 10-U-235 1.0102 x 10-3 U(4.306)0 2 Fuel U-236 5.1395 x 10-6 U-238 2.2157 x 10-2 O 4.6753 x 10-2 Al 5.8433 x 10-2 5

Cr 6.2310 x 10-Cu 6.3731 x 10-5 Mg 6.6651 x 10-4 6061 Aluminum Clad Mn 2.2115 x 10-5 (2.69 g/cm 3) TiTi 2.5375 2.5375 xx10.

10.5 5

Zn 3.0967 x 10-5 Si 3.4607 x 10-4 Fe 1.0152 x 10-4 C 4.3562 x 10-2 H 5.8178 x 10-2 Rubber End Plug Ca 2.5660 x 10-3 (1.498 g/cm3) S 4.7820 x 10-4 Si 9.6360 x 10.5 2

0 1.2461 x 10-Page 12

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Table 2-3. Moderator-Reflector Atom Densities for LEU-COMP-THERM-002 Material Isotope Atom Density Material _ _ Isotope (barn-cm)_l H 6.6706 x 10-2 Water(')

O 3.3353 x 10-2 H 5.6642 x 10-2 Acrylic C 3.5648 x 10-2 2

O 1.4273 x 10-1 This is 0.997766 g/cm 3 , interpolated from densities at 20'C and 250C 3 (CRC Handbook of Chemistry and Physics, 68th edition, p F-10.)

Page 13

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 2.3. LEU-COMP-THERM-006 This series of eighteen critical experiments involving lattices composed of U(2.6%)0 2 pins in a large water tank performed at the Tank Critical Assembly (TCA) in Japan the late 1970's. These experiments included individual clusters of pins arranged on square pitches of 1.849, 1.956, 2.150 and 2.293 cm and are described in detail in Reference 7. Seven different basic pin cluster arrangements were used (Figure 2-6) and unique critical water level heights reported for each.

0000 ~0000 00000000000000 00000000000000000 0000800000880088888 000000000000008 888800000000 0 8000000000 80088808800888088 00 0000 000000000000000 0000000000000000 00000000000000000 000000000000000 0000000000000000 00000000000000000 000000000 00 0000 0 00000000000000000 0800080000000 00808088800888888 000000000000000 000OOOOOO000000 88888888880088088 0000000000000000 OOOOOOOOOOO0 88080808088808888 00000000000000000 OOOOOOOOO 000000000000000 8888oo8o88o8ooo 000000000000000 000000000000000088888888888888 88888888888888888 8888888888888888 00000000000000000 0000000000000000 000000000000000 0000000000000000 00000000000000000 0oo00ooo0008888 88880888880008088 00000000000000000 000000000000000 0000000000000000 00000000000000000 ooooooooooooo 88880008888888808 Pattern No. I Pattern No. 2 Pattern No. 3 (15 XI5) ( 16 X 16) ( 17 X 17 )

0000000000000000000 88888888888888888 000000000000000000 0000000000000000000 0000000000000000000 000000000000000000 0000000000000000000 000000000000000000 0000000000000000000 000000000000000000 0000000000000000000 0000000000000000000 000000000000000000 0000000000000000000 000000000000000000 88800008800080088888800 0000000000000000000 0000000000000000000 0000000000000000000 000000000000000000 0000000000000000000 000000000000000000 0000000000000000000 000000000000000000 0000000000000000000 000000000000000000 000000000000000000 0000000000000000000 0000000000000000000 0000000000000000000 00000000000000000 00000000000000000 0000000000000000000 000000000000000000 0000000000000000000 Pa tcrn No. 4 Pattern No. 5 (1008X018) ( 19X 19) 000000000000000000000 00000000000000000000 00000000000000000000 000008088800008800000 00000000000000000000 00000000000000000000 00000000000000000000 000000000000000000000 00000000000000000000 000000000000000000000 88808888088808888888888 000000000000000000000 000000000000000000000 00000000000000000000 00000000000000000000 8808888088888888880888 00000000000000000000 00000000000000000000 000000000000000000000 00000000000000000000 00000000000000000000 000000000000000000000 8888888888880088008888 000000000000000000000 000000000000000000000 00000000000000000000 0000000880808888888888 00000000000000000000 000000000000000000000 00000000000000000000 00000000000000000000 000000000000000000000 00O00000000000000000 000000000000000000000 000000000000000000000 PattertnNo. 6 Pattern, No. 7 (20 X 20) (21 X 21)

Figure 2-6.

Square Pin Cluster Arrays for LEU-COMP-THERM-006 Page 14

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 The fuel pins used in the experiments were 1.25 cm in diameter and 144.15 cm in active length clad in Aluminum with an OD of 1.417 cm and a wall thickness of 0.076 cm. Figure 2-7 provides a schematic picture of the fuel rod.

Al end plug Al cladding Al wool UO2 pellet Al end plug Top r Bottom (Dimensions in mm)

Figure 2-7.

U(2.60%)0 2 Fuel Rod Square arrangements of pin clusters ranging from 15x15 to 21x21 were constructed at each of the four pin-lattice spacings of 1.849, 1.956, 2.150 and 2.293 cm. Then the water level height in the tank was increased until a critical configuration was achieved. Since all fuel pins were of similar composition and size and all lattices were arranged on square pitches, the effective water-to-fuel (W/F) ratio for these experiments ranged from 1.5 to 3.0. This makes them suitable for benchmarking BWR reactor lattice configurations.

Table 2-4 provides the material atom densities used for all cases. This data was taken directly from Table 14 of Reference 7 with no modification.

Page 15

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Table 2-4.

Atom Densities for LEU-COMP-THERM-006 Atom Density Region Material Wt.% (xl 024 atoms/cm 3 )

234U(2) 0.021 4.8872xl 0"6 235u 2.596 6.0830x10-4 238u 97.383 2.2531x10-2 O - 4.7214x10-2 Aluminu - 5.5137xl 0-2 Cladding(3 ) m Water H - 6.6735x10-2 O - 3.3368x 10-2 235 2 The fraction 0.008 x Uwt.% was assumed.

3 homogenized with air gap Page 16

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 2.4. LEU-COMP-THERM-009 This series of twenty-seven extrapolated critical experiments involving lattices composed of U(4.31%)0 2 pins in a large water tank performed at the Pacific Northwest Laboratory (PNL) in the late 1970's (Refs. 4-6). These experiments involved three rectangular clusters of pins arranged on a square pitch of 2.54 cm with steel, borated steel, Boral, copper, cadmium, aluminum and zirconium plates of varying thickness positioned in between the clusters. Of the twenty-seven experiments reported, only thirteen are judged to be acceptable as benchmarks for this validation since the experiments with copper and cadmium plates are not representative of BWR spent fuel storage configurations.

The fuel pins used in the experiments are similar to those used in LEU-COMP-THERM-002 and were 1.265 cm in diameter and 91.44 cm in active length clad in 6061 Aluminum with an OD of 1.415 cm and a wall thickness of 0.066 cm. Figure 2-8 provides a schematic picture of the fuel rod.

Fuel Cladding 1.265 + 0.003 cm diameter 1.415 +/--0.003 cm OD x 0.066 cm wall Rubber end cap Rubber end cap 1.278 cm OD x pellets 1.278 cm ODx 2.54 cm long 2.54 cm long 91.44 cm (min) 92.71 cm (max) 96,52+/-0,3 cm c98 0839 Figure 2-8.

U(4.31%)0 2 Fuel Rod Page 17

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Different arrangements of pin clusters were constructed using the steel, borated steel, Boral, aluminum and zirconium plates. Then, the separation distance between the clusters was reduced until a critical configuration was extrapolated. Since all fuel pins were of similar composition and size and all lattices were arranged on a 1.892 cm square pitch, the effective water-to-fuel (W/F) ratio for these experiments was determined to be -1.9. This makes them suitable for benchmarking BWR reactor lattice configurations inside a typical spent fuel storage rack geometry.

Figure 2-9 provides a schematic description of one of the benchmark experiments showing the relative pin-lattice arrangements, absorber plate locations and water separation distances.

Bantad Sled PataS 327 ern er 2.U8 liii UIN id X35.6 am Cue 8: x91 am long Outer duster (15 x 8) Center duster (15 x 8) Outer duste (16 x )

ocooooooo' 6obob655oTh55T~5 OODOOOO000000 ooho~h

,Pfc2 0 0 2 0 o

2]

io~o~oaooooooooo r6T56ob655oTh5O_56oThT5O Pitch 2.00& O00 O005] 2 n

7"'ý n

0000000020.0001 000000000000 n r 0

O 000000000000000 oooooooooo5_ 0 (5Ooo 00 OOOA 00000000000 OO0000000 00000000000 00000 0 0005 0 *0 00000000O 0000001000 I8.1 am 38.1 cm 38.1 Om Figure 2-9.

Pin Cluster Arrays with Borated Steel Plates for LEU-COMP-THERM-009 Tables 2-5, 2-6, 2-7, 2-8, 2-9 and 2-10 provide the material atom densities used for all cases. This data was taken directly from Tables 27, 28, 29, 30, 31 and 32 of Reference 6 with no modification.

Page 18

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision I Table 2-5. Fuel-Rod Atom Densities for LEU-COMP-THERM-009 Atom Density Material Isotope (barn-cm).l 234u 5.1835 x 106 235u 1.0102 x 10-3 236u 5.1395 x 10-'

U(4.306)0 2 Fuel 2.2157x10 2 2

O 4.6753 x 10-Al 5.8433 x 10-2 5

Cr 6.2310 x 10-Cu 6.3731 x 10-5 Mg 6.6651 x 10-4 Mn 2.2115 x 10. 5 6061-Aluminum Clad 10-5 (2.69 g/cm 3 ) Ti 2.5375 x 10-5 Zn 3.0967 x10 5 Si 3.4607 x 10-4 Fe 1.0152 x 104 C 4.3562 x 10-2 H 5.8178 x 10-2 Ca 2.5660 x 10-3 Rubber End Plug (1.498 g/cm 3 ) S 4.7820 x 10-5 Si 9.6360 x10 5 0 1.2461 x 10-2 Page 19

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Table 2-6. Steel Absorber-Plate Atom Densities for LEU-COMP-THERM-009 Material Isotope wt.% Atom Density (barn-cm).l Cr 18.56 1.7046 x 10-2 Cu 0.27 2.0291 x 10-4 304L Steel without Fe 68.24 5.8353 x 10-2 3 Mn 1.58 1.3734 x 10-3 B (7.93 g/cm )

Mo 0.26 1.2942 x 10-4 Ni 11.09 9.0238 x 10.3 l°B 1.05 wt.% boron, 19.9 at.% 10B 9.1950 x 10-4 11 11 1.05 wt.% boron, 80.1 at.% B 3.7011 x 10- 3 Cr 19.03 1.7412 x 10-2 304L Steel with 1.1 Cu 0.28 2.0963 x 10-4 wt.% B (7.9 g/cm 3 ) Fe 68.04 5.7961 x 10-2 Mn 1.58 1.3682 x 10-3 Mo 0.49 2.4298 x 10-4 Ni 9.53 7.7251 X 10-3 10B 1.3953 x 10-3 1°B 1.62 wt.% boron, 19.9 at.%

11B 11B 5.6163 x 10-3 1.62 wt.% boron, 80.1 at.%

Cr 19.6 1.7638 x 10-2 304L Steel with 1.6 Cu 0.26 1.9145 x 10-4 wt.% B (7.77 102 g/cm 3) Fe 66.4 5.5634 x 10-3 Mn 1.69 1.4394 x10 3 Mo 0.31 1.5119 x 10-4 Ni 10.12 8.0684 x 10-3 Page 20

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Table 2-7. Boral Absorber-Plate Atom Densities for LEU-COMP-THERM-009 Material Isotope Wt.% Atom Density Al 62.39 3.4673 x 10-2 0 7.9217 x 10-3 10B 28.7 wt.% boron, 19.9 at. % ' B 11B 11 3.1886 x 10-2 28.7 wt.% boron, 80.1 at. % B C 7.97 9.9501 x 10-3 Cr 0.05 1.4419 x 10. 5 Cu 0.09 2.1237 x 10.5 B4C-AI(4) Fe 0.33 8.8606 x 10-5 (2.49 g/cm3) Mg 0.05 3.0848 x 10.5 Mn 0.05 1.3647 x 10-5 Na 0.02 1.3045 x 10-5 Ni 0.02 5.1099 x 10-6 Si 0.2 1.0678 x 10-4 S 0.03 1.4027 x 105 Zn 0.1 2.2932 x 10-5 Al 99.0 5.9660 x 102 Cu 0.12 3.0705 x 10-5 1100 5 Aluminum(5( ) Mn 0.025 7.3991 x 10-6 (2.70 g/cm 3) Zn 0.05 1.2433 x 10.5 Si 0.4025 2.3302 x 10-4 Fe 0.4025 1.1719 x 10-4 4 middle 0.509-cm thickness of plate 5 0.102-cm-thick clad on both sides of B4C-AI Page 21

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Table 2-8. Copper Absorber-Plate Atom Densities for LEU-COMP-THERM-009 Material Isotope Wt.% Atom Density C 0.34 1.5194 x 10-3 Cu 99.6 8.4128 x 10-2 Fe 0.004 3.8444 x 10 6 Copper without Mg 0.002 4.4168 x 10.6 Cd (8.913 g/cm 3) Na 0.002 4.6695 x 106 O 0.03 1.0064 x 10-4 Si 0.02 3.8223 x 10-5 S 0.002 3.3474 x 106 10 4.9384 x 10.6 10B 0.005 wt.% boron, 19.9 at.% B 11B 0.005 wt.% boron, 80.1 at.%

11B 1.9878 x 10-5 C 0.002 8.9346 x 10-6 Cd 0.989 4.7208 x 10-4 Cu 98.685 8.3328 x 10-2 Copper with Cd Fe 0.02 1.9216 x 10.5 (8.910 g/cm 3) Mn 0.009 8.7901 x 10-6 Ni 0.01 9.1424 x 10.6 O 0.019 6.3720 x 10.5 Si 0.004 7.6419 x 10.6 Sn 0.25 1.1300 x 10-4 Zn 0.007 5.7440 x 10-6 Page 22

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Table 2-9. Cadmium, Aluminum, and Zircaloy-4 Absorber-Plate Atom Densities for LEU-COMP-THERM-009 Atom Density Material Isotope Wt.% (barn-cm)-1 Cadmium Cd 99.7 4.6201 x 10-2 (8.65 g/cm 3) Zn 0.3 2.3899 x 10-4 Aluminum Al 97.15 5.8371 x 10-2 (2.692 g/cm 3) Cr 0.21 6.5475 x 10.'

Cu 0.12 3.0614 x 10-5 Fe 0.82 2.3803 x 10-4 Mn 0.21 6.1968 x 10-5 Si 0.82 4.7332 x 10-4 S 0.06 3.0330 x 105 Ti 0.61 2.0654 x 10.4 Zircaloy-4 Zr 98.16 4.0953 x 10-2 (6.32 g/cm 3) Fe 0.21 1.4311 x 10.4 Sn 1.5 4.8092 x 10.4 Cr 0.13 9.5156 x 10-5 Table 2-10. Moderator-Reflector Atom Densities for LEU-COMP-THERM-009 Material Isotope Atom Density (barn-cm)-'

Water H 6.6675 x 10-2 2

O 3.3338 x 10-Acrylic H 5.6642 x 10-2 2

C 3.5648 x 10-2 0 1.4273 x 10-Page 23

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 2.5. LEU-COMP-THERM-016 This series of thirty-two extrapolated critical experiments involving lattices composed of U(2.35%)0 2 pins in a large water tank performed at the Pacific Northwest Laboratory (PNL) in the late 1970's (Refs. 4-6). These experiments involved three rectangular clusters of pins arranged on a square pitch of 2.032 cm with steel, Boral, copper, cadmium, aluminum and zircalloy-4 plates of varying thickness positioned in between the clusters. Of the thirty-two experiments reported, only twenty are judged to be acceptable as benchmarks for this validation since the experiments with copper and cadmium plates are not representative of BWR spent fuel storage configurations.

The fuel pins used in the experiments are similar to those used in LEU-COMP-THERM-001 and were 1.1176 cm in diameter and 91.44 cm in active length clad in 6061 Aluminum with an OD of 1.27 cm and a wall thickness of 0.0762 cm. Figure 2-10 provides a schematic picture of the fuel rod.

Fuel specifications: 2.35% enriched UO2 Fuel rods

1. Rod dimensions Fuel Cladding 0.44 in. dia. 0.500 in. OD (1.27 cm)

Top end plug (1.1176 cm) 0.030 in. wall (0.0762 cm) 0.500 in. dia. end plug (1.21 cm) 2.0 in. .0 36.0in.

(5.08 cm) (91.44 cm) 38.5 in.

197.79cml

2. Cladding: 6061 Aluminum tubing seal welded with a lower end plug of 5052-H32 Aluminum and a top plug of 1100 Aluminum.

3. Total weight of loaded fuel rods: 917 g (average)

Fuel loading

1. Fuel mixture vibrationally compacted.

2. 825 g of UO, powdered/rod, 726 g of U/rod, 17.08 g of U-235/rod.

3. Enrichment = 2.35 - 0.05 w/o U-235.

4. Fuel density = 9.20 g/cm (84% theoretical density).

Figure 2-10.

U(2.35%)0 2 Fuel Rod Page 24

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Different arrangements of pin clusters were constructed using the steel, borated steel, Boral, aluminum and zircalloy-4 plates. Then, the separation distance between the clusters was reduced until a critical configuration was extrapolated. Since all fuel pins were of similar composition and size and all lattices were arranged on a 2.032 cm square pitch, the effective water-to-fuel (W/F) ratio for these experiments was determined to be -3.2. This makes them suitable for benchmarking BWR reactor lattice configurations inside a typical spent fuel storage rack geometry.

Figure 2-11 provides a schematic description of one of the benchmark experiments showing the relative pin-lattice arrangements, absorber plate locations and water separation distances.

ý_ "40.640cm Figure 2-11.

Pin Cluster Arrays with Steel Plates for LEU-COMP-THERM-016 Tables 2-11, 2-12, 2-13, 2-14 and 2-15 provide the material atom densities used for all cases. This data was taken directly from Tables 34, 35, 36, 37 and 38 of Reference 6 with no modification.

Page 25

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Table 2-11. Fuel Rod Atom Densities for LEU-COMP-THERM-016 Material Isotop wt.% Atom Density e (barn-cm)-I 234 u --- 2.8563 x 10-6 235u --- 4.8785 x 10-4 U0 2 Fuel 236u --- 3.5348 x 106 238 u --- 2.0009 x 10-2 0 --- 4.1202 x 10-2 Al 99.0 5.9660 x 10-2 Cu 0.12 3.0705 x 10. 5 1100 Aluminum (top end plug; Mn 0.025 7.3991 x 10-6 2.70 g/cm 3 ) Zn 0.05 1.2433 x 10-5 Si 0.4025 2.3302 x 10-4 Fe 0.4025 1.1719 x 10-4 Al 96.65 5.8028 x 10-2 Cr 0.25 7.7888 x 10-5 Cu 0.05 1.2746 x 10.5 5052 Aluminum (lower end Mg 2.5 1.6663 x 10-3 plug; 2.69 g/cm 3) Mn 0.05 1.4743 x 10-3 Zn 0.05 1.2387 x 10-5 Si 0.225 1.2978 x 10-4 Fe 0.225 6.5265 x 10-5 Al 97.325 5.8433 x 10-2 Cr 0.2 6.2310 x 10.5 Cu 0.25 6.3731 x 10-5 Mg 1.0 6.6651 x 10-4 6061 Aluminum (clad; 2.69 10-g/cm 3 ) Mn 0.075 2.2115 x 10-5 Ti 0.075 2.5375 x 10.

Zn 0.125 3.0967 x 10.5 Si 0.6 3.4607 x 10-4 Fe 0.35 1.0152 x 10-4 Page 26

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Table 2-12. Steel Absorber-Plate Atom Densities for LEU-COMP-THERM-016 Atom Density Material Isotope Wt.% Density (barn-cm)-I Cr 18.56 1.7046 x 102 Cu 0.27 2.0291 x 10-4 304L Steel without B Fe 68.24 5.8353 x 10.2 (7.93 g/cm 3) Mn 1.58 1.3734 x 10.'

Mo 0.26 1.2942 x 10-4 Ni 11.09 9.0238 x 10.3 10B 1.05 x 0.18431 9.1950 x 10- 4 11B 1.05 x 0.81569 3.7011 x 10- 3 Cr 19.03 1.7412 x 10- 2 304L Steel with 1.1 wt.% B Cu 0.28 2.0963 x 10-2 (7.9 g/cm 3 ) Fe 68.04 5.7961 x 10-2 Mn 1.58 1.3682 x 10- 2 Mo 0.49 2.4298 x 10-4 Ni 9.53 7.7251 x 10-3 10B 1.62 x 0.18431 1.3953 x 10- 3 11B 1.62 x 0.81569 5.6163 x 10- 3 Cr 19.6 1.7638 x 10- 2 304L Steel with 1.6 wt.% B Cu 0.26 1.9145 x 10-4 (7.77 g/cm 3) Fe 66.4 5.5634 x 10-2 Mn 1.69 1.4394 x 10-3 Mo 0.31 1.5119 x 10"4 Ni 10.12 8.0684 x 10- 3 Page 27

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Table 2-13. Boral/Copper Plate Atom Densities for LEU-COMP-THERM-016 Material Isotope Wt.% Atom Density Al 62.39 3.4673 x 10-2 1°B 28.7 x 0.18431 7.9217 x 10-3 11B 28.7 x 0.81569 3.1886 x 10-2 C 7.97 9.9501 x 10.'

Cr 0.05 1.4419 x 10-5 Cu 0.09 2.1237 x 10-5 Boral Fe 0.33 8.8606 x 10-5 (2.49 g/ cm 3) Mg 0.05 3.0848 x 10-5 Mn 0.05 1.3647 x 10-5 Na 0.02 1.3045 x 10-'

Ni 0.02 5.1099 x 10-6 Si 0.2 1.0678 x 10-4 S 0.03 1.4027 x 10.5 Zn 0.1 2.2932 x 10-5 10 B 0.005 x 0.18431 4.9384 x 10-6 11B 0.005 x 0.81569 1.9878 x 10.6 C 0.002 8.9346 x 10.'

Cd 0.989 4.7208 x 10-4 Cu 98.685 8.3328 x 10-2 Copper with Cd Fe 0.02 1.9216 x 10-5 (8.910 g/ cm 3) Mn 0.009 8.7901 x 10-6 Ni 0.01 9.1424 x 10-6 O 0.019 6.3720 x 10"5 Si 0.004 7.6419 x 10-6 Sn 0.25 1.1300 x 10-4 Zn 0.007 5.7440 x 10-6 C 0.34 1.5194 x 10-3 Cu 99.6 8.4128 x 10-2 Fe 0.004 3.8444 x 10-6 Copper without Cd (8.913 Mg 0.002 4.4168 x 10.6 g/ cm3) Na 0.002 4.6695 x 10-6 O 0.03 1.0064 x 10-4 Si 0.02 3.8223 x 10-5 S 0.002 3.3474 x 10-6 Page 28

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Table 2-14. Cadmium, Aluminum, and Zircaloy Absorber-Plate Atom Densities for LEU-COMP-THERM-016 Material Isotope Wt.% Atom Density (barn-cm)-I Cadmium Cd 99.7 4.6201 X 10-2 3 Zn 0.3 2.3899 x 10-4 (8.65 g/cm )

Al 97.15 5.8371 X 10-2 Cr 0.21 6.5475 x 10. 5 Cu 0.12 3.0614 x 10-5 Aluminum Fe 0.82 2.3803 x 10-4 (2.692 g/cm 3) Mn 0.21 6.1968 x 10-5 Si 0.82 4.7332 x 10-4 S 0.06 3.0330 x 10. 5 Ti 0.61 2.0654 x 10-4 Zr 98.16 4.0953 x 10-2 Zircaloy-4 Fe 0.21 1.4311 x 10-4 (6.32 g/cm 3) Sn 1.5 4.8092 x 10-4 Cr 0.13 9.5156 x 10. 5 Table 2-15. Moderator-Reflector Atom Densities for LEU-COMP-THERM-016 Atom Density (barn-Material Isotope cm)-1 Water H 6.6743 x 10-2 0 3.3371 X 10-2 H 5.6642 x 10-2 Acrylic C 3.5648 x 10-2 2

0 1.4273 x 10-Page 29

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 2.6. LEU-COMP-THERM-034 This series of twenty-six critical experiments involving lattices composed of U(4.738%)0 2 pins in a large water tank performed at the Valduc facility in France in the early 1980's (Reference 8). These experiments involved four individual 18x18 pin clusters (each with a square pitch of 1.6 cm) arranged on a table-top surface. The pin-clusters were then outfitted with square canisters of borated stainless steel, Boral and cadmium placed over them while the critical water level height was determined for a variety of cluster separation distances. Figure 2-12 shows a picture of the four clusters (without canisters) sitting on the table-top surface.

Figure 2-12.

Valduc Experimental Configuration Page 30

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Of the twenty-six experiments reported, only fifteen are judged to be acceptable as benchmarks for this validation since the experiments with cadmium canisters are not representative of BWR spent fuel storage configurations.

The fuel pins used in the experiments were 0.79 cm in diameter and 90 cm in active length clad in Aluminum with an OD of 0.94 cm and a wall thickness of 0.06 cm.

Figure 2-13 provides a schematic picture of the fuel rod.

I CW0 BM AGS PkBimmp.

200 Figure 2-13.

U(4.738%)0 2 Fuel Rod in Support Plate Structure Page 31

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 The array of four 18x1 8 pin-clusters was changed by re-positioning the lattices on the table-top at different separation distances with and without the borated stainless steel and boral canister covers. Then, the tank water level height was increased until a critical configuration was achieved. Since all fuel pins were of similar composition and size and all lattices were arranged on a 1.6 cm square pitch, the effective water-to-fuel (W/F) ratio for these experiments was determined to be -4.2. This makes them suitable for benchmarking BWR reactor lattice configurations inside a typical spent fuel storage rack geometry.

Figure 2-14 provides a schematic description of one of the benchmark experiments showing the relative pin-lattice arrangements, absorber plate locations and water separation distances.

Absorber plates 00000000000000000 gO0000000000000000 00000000000000000 000000000000000000 0000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 %pitch Water gap 000000000000000000 000000000000000000 0.8 cm thickness 000000000000000000 000000000000000000

@0000000000000000G 800000000000000006 Optional rod 00000000000000000 00000000000000000!

000000000000000000 000000000000000000 lie rod -. P00000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 Fuel rod --

000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 000000000000000000 00000000000000000 Q0000000000000000. 600000000000000006 I

\- Instrumentation thimble Figure 2-14.

Pin Cluster Arrays with Canister for LEU-COMP-THERM-034 Page 32

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Tables 2-16 and 2-17 provide the material atom densities used for all cases. This data was taken directly from Tables 13 and 14 of Reference 8 with no modification.

Table 2-16. Atom Densities for Basic Materials for LEU-COMP-THERM-034 (atoms/barn-cm) 234u 7.1318 x 10-6 235u 1.1104 x 10-3 236u 3.1838 x 10-5 U0 2 238u 2.2006 x 10-2 O 4.6391 x 10-2 l°B3 5.7531 x 10-8 1113 2.3'157 x 10-7 H 6.6707 x 10-2 Water (22 'C) H 3.3354x10 2 O 3.3354 x 10.2 Al 5.9569 x 10-2 Mg 3.1442 x 10-4 Aluminum Alloy AGS Si 2.4894 x 10-4 (clad, plugs) Fe 6.4052 x 10-5 Zn 7.4597 x 1006 Stainless Steel Fe 5.8694 x 10-2 Z2 CN18/10 1 Cr 1.6469 x 10-2 (support plates, Ni 8.1061 x 10-3 grid plates, Mn 1.7319 x 10-3 tie rods, Si 1.6939 x 10-3 instrumentation P 6.1438 x 10-5 thimbles, cover for S 4.4504 x 10-5 cadmium plates) C 1.1883 x 10-4 Page 33

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Table 2-17. Atom Densities for Absorber Materials for LEU-COMP-THERM-034 (atoms/barn-cm).

Fe 5.7220 x 10-2 Cr 1.7203 x 10-2 2

Ni 1.0707 x 10-Mn 5.9877 x 10-4 Si 1.0507 x 10-3 Borated Steel x 10-5 P 4.6855 S 9.0506 x 10-6 C 1.4499 x 10-4 1013 9.7950 x 10-4 11 B 3.9426 x 10-3 Aluminum (6) Al 5.9169 x 10-2 C 8.0894 x 10-3 B4C + Al (7) Al 4.1873 x 10-2 3

1013 6.4448 x 10-11 B 2.5941 x 10-2 Cadmium Cd 4.6340 x 10-2 6 0. 11 -cm-thick Boral external plates.

1 0.43-cm-thick internal absorbing sheet of Boral.

Page 34

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 2.7. LEU-COMP-THERM-039 This series of seventeen critical experiments involving lattices composed of U(4.738%)0 2 pins in a large water tank performed at the Valduc facility in France in the early 1980's (Reference 9). These experiments involved a single 22x22 (or 21x21) pin cluster array (each with a square pitch of 1.26 cm) arranged on a table-top surface. These experiments are categorized as "incomplete array" geometries since selected fuel pins were removed from the lattice in a particular sequence or pattern and the critical water level height re-established for each case. Figure 2-15 shows a picture of the rod cluster sitting on the table-top surface.

-77 Figure 2-15.

Valduc Experimental Configuration Page 35

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Of the seventeen experiments reported, all are judged to be acceptable as benchmarks for this validation report.

The fuel pins used in the experiments are similar to those described in LEU-COMP-THERM-034 and were 0.79 cm in diameter and 90 cm in active length clad in Aluminum with an OD of 0.94 cm and a wall thickness of 0.06 cm. Figure 2-16 provides a schematic picture of the fuel rod.

6.9 ' __ -Spring, 34 turns 0.1-cm diameter 0.78-cm external diameter

--f Pellets of UO, 4.738% enrichment 0.79-cm diameter 1.5-cm long 9+1 Clad, AGS I I

0.82-cm inside diameter 0.94-cm outside diameter Bottom plug, AGS Dimensions in cm GcM.W Figure 2-16.

U(4.738%)0 2 Fuel Rod Page 36

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Fifteen of the seventeen experiments were performed with an incomplete 22x22 pin array while the remaining two were performed with a 21x21 array. After each experiment, a different group of fuel rods was removed/replaced from the array in a particular pattern. Then, the tank was flooded and the water level height was increased until a critical configuration was achieved. Although all fuel pins were of similar composition and size and all lattices were arranged on a 1.26 cm square pitch, the effective water-to-fuel (W/F) ratio inside the array varied depending on the number of rods removed from the array during each experiment. The W/F ratio for these seventeen experiments is calculated to vary from 2.4 to 3.4. This makes them suitable for benchmarking BWR reactor lattice configurations.

Figure 2-17 provides a schematic description of several of the incomplete array configurations created during the experiments. This set of experiments are particularly relevant to BWR reactor lattices since the incomplete array configurations look quite similar to the vanished lattice arrays frequently analyzed in spent fuel criticality safety analyses.

00*000000000000000000*0 00000000000 00000000000000000000 00*00*00000000000000000 UU

.ooooooo~oo.oo~.ZolUl31*lll83 18131133 O0000000 :0000OO0000O I'"'""'" '""" Iiciipiete: rragurations

FigureO2O1O.

Figure 2-17.

Schematic of Two Incomplete Array Configurations Page 37

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Table 2-18 provides the material atom densities used for all cases. This data was taken directly from Table 9 of Reference 9 with no modification.

Table 2-18. Atom Densities for Basic Materials for LEU-COMP-THERM-039 (atoms/barn-cm) 2 35 u 1.1104 x 10-3 238u 2.2006 x 10-2 234u 7.1318 x 10-6 U0 2 2 36 u 3.1838 x 10-5 O 4.6391 X 10-2 108 5.7531 x 10-8 118 2.3157 x 10-7 Al 5.9569 x 10-2 AGS Mg 3.1442 x 10-4 (clad, plugs) Si 2.4894 x 10-4 Zn 7.4597 x 10-6 Fe 6.4052 x 10-5 N 4.1805 x 10-5 Air O 1.2633 x 10-5 Water 0 3.3353 x 10-2 Density = 0.9980(8) H 6.6706 x 10-2 C 1.1883 x 10-4 Cr 1.6469 x 10-2 Fe 5.8694 x 10-2 Stainless steel Mn 1.7319 x 10-3 (grid, pedestal plate) Ni 8.1061 x 10-3 Si 1.6939 x 10-3 S 4.4504 x 10-5 31pP 6.1438 x 10-5 8

at 22 'C.

Page 38

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 2.8. LEU-COMP-THERM-062 This series of fifteen critical experiments involving lattices composed of U(2.6%)0 2 pins in a large water tank performed at the Tank Critical Assembly (TCA) in Japan the early 1990's (Reference 7). These experiments involved a single, 18x18 rod cluster array of fuel pins (1.9558 cm pitch) with and without a single borated stainless plate of varying thickness and boron content adjacent to the rod cluster. Figure 2-18 shows a schematic picture of the array with a borated stainless steel plate.

Water T 30 4.897T8 S@606 0@60*000***@

Io 809660069006066696eS to Cf)

I 60060t a 6 001010-t 0S b

Am d9A& do h@MS@ h@ hAm n d ---,

35W2044 4.897 35.2044 a-97

Pellet fuel rod 30 7 Water

Swaged fu lrod I Borated stainless steel Dimensions in cm 02 GASO&Q-251 Figure 2-18.

Schematic of Array with Borated Stainless Steel Plate Of the fifteen experiments reported, all are judged to be acceptable as benchmarks for this validation report.

Page 39

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 The fuel pins used in the experiments were manufactured by GE in the early 1960's and were 1.2502 cm in diameter and 144.15 cm in active length clad in Aluminum with an OD of 1.4172 cm and a wall thickness of 0.0762 cm. Figure 2-19 provides a schematic picture of the pellet (top) and swaged (bottom) fuel rods used in the experiments.

Al end plug

. Al wool Al end plug

/ Al cladding TOP j<. Bottom (Dimensions in mm)

) Bottom (Dimensions in mm)

Figure 2-19.

Pellet and Swaged Fuel Rods Page 40

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Six of the experiments were performed with 0.67 wt.% boron stainless steel plates with two different plate thicknesses of 0.3114 and 0.6228 cm. Four were performed with 0 wt.% boron stainless steel plates with plate thicknesses of 0.2910 and 0.5820 cm. Four were performed with 0.98 wt.% stainless steel plates with plate thicknesses of 0.3097 and 0.6194 cm. One experiment was performed with no plate at all. The critical water level height was established for each unique combination of stainless steel plate wt.% boron, plate thickness and spacing between the plate and the rod array cluster. Since all fuel pins were of similar composition and size and all lattices were arranged on a 1.9558 cm square pitch, the effective water-to-fuel (W/F) ratio inside the array was -2.1. In addition, the stainless steel and borated stainless steel plate thicknesses are representative of typical spent fuel storage rack cell dimensions and compositions. This makes them suitable for benchmarking BWR reactor lattice configurations inside a spent fuel storage rack geometry.

Tables 2-19, 2-20, 2-21, 2-22, 2-23 and 2-24 provide the material atom densities used for all cases. This data was taken directly from Tables 19, 20, 21, 22, 23 and 24 of Reference 7 with no modification.

Page 41

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Table 2-19. Fuel Atom Densities for LEU-COMP-THERM-062 Isotopic Atom density (barn-Material Isotope composition (wt.%)

234 U 0.0208 4.8825 x 10-6 235u 2.60 6.0771 x 10-4 U0 2 Pellet 97.3792 2.2474 x 10-2 O - 4.7002 x 10-2 234u 0.0206 4.6478 x 10-6 UO2 235u 2.58 5.7850 x 10-4 Powder 2 38 u 97.3994 2.1564 x 10-2 O - 4.4367 x 10-2 Table 2-20. Atom Densities of 6061 Aluminum Alloy for LEU-COMP-THERM-062 Material Element Wt.% Atom density (barn-cm)1 Al 97.325 5.8433 x 10-2 Cr 0.2 6.2310 x 10-5 Cu 0.25 6.3731x 10-Cladding, top and bottom end plugs, upper and lower grid Mg 1.0 6.6651 x 10-4 plates, support plate Mn 0.075 2.2115 x 10-5 g/cm3) Ti 0.075 2.5375 x 10-5 (density 2.69 Zn 0.125 3.0967 x 10-5 Si 0.6 3.4607 x 10-4 Fe 0.35 1.0152 x 10- 4 Page 42

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Table 2-21. Atom Densities of Stainless Steel for LEU-COMP-THERM-062 Material Element Atom density (barn-cm)'

C 1.1928 x 10-4 Si 1.7003 x 10-3 Lower support Mn 1.7385 x 10-3 plate P 6.9381 x 10-5 S.S.304L(a) S 4.4673 x 10-5 (SUS304L) Ni 8.9509 x 10-3 Cr 1.7450 x 10-2 Fe 5.7202 x 10-2 Table 2-22. Atom Densities of Stainless Steel Plate for LEU-COMP-THERM-062 Material Element Wt.% Atom density (barn-cm)-'

C 0.06 2.3862 x 10-4 Si 0.45 7.6534 x 10-4 Stainless steel, Mn 0.83 7.2165 x 10-4 boron content 0 wt.% P 0.026 4.0096 x 10-5 S 0.008 1.1916 x 10-5 density 7.932 Cr 18.23 1.6747 x 10-2 g/cm 3 Ni 8.70 7.0807 x 10-3 Fe 71.696 6.1322 x 10-2 Page 43

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Table 2-23. Atom Density of 0.67-Wt.%-Borated Stainless Steel Plate for LEU-COMP-THERM-062 Atom density Material Element Wt.% density (barn-cm)-I C 0.01525 5.9632 x 10-5 Si 0.7275 1.2166 x 10-3 Mn 1.785 1.5260 x 10-3 Stainless steel P 0.0255 3.8666 x 105 Boron content S 0.001 1.4645 x 10.6 0.67 wt.% Cr 19.715 1.7808 x 10-2 Ni 9.955 7.9664 x 10-3 Density 7.799 g/cm 3 Mo 0.575 2.8148 x 10-4 10B 5.7923 x 10-4 B 0.67 11 B 2.3315 x 10-3 Fe 66.53075 5.5951 x 10-2 Table 2-24. Atom Density of 0.98-Wt.%-Borated Stainless Steel Plate for LEU-COMP-THERM-062 Material Element Wt.% Atom density (barn-cm)-I C 0.01 3.9183 x 10-5 Si 0.435 7.2893 x 10-4 Mn 1.6675 1.4285 x 10-3 Stainless steel P 0.01125 1.7094 x 10- 5 Boron content S 0.00375 5.5031 x 10-6 0.9825 wt.% Cr 19.3475 1.7512 x 10-2 Density Ni 10.1625 8.1492 x 103 7.815 g/cm 3 Mo 0.6 2.9433 x 10-4 10B 8.5113 x 10-4 B8B 3.4259 x 10-3 Fe 66.78 5.6276 x 10-2 Page 44

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 2.9. LEU-COMP-THERM-065 This series of seventeen critical experiments involving lattices composed of U(2.6%)0 2 pins in a large water tank performed at the Tank Critical Assembly (TCA) in Japan the early 1990's (Reference 10). These experiments involved two, 18x18 rectangular rod array clusters (1.9558 cm pitch) with and without double borated stainless plates of varying thickness and boron content in between the rod clusters.

Figure 2-20 shows a schematic picture of the arrays with a borated stainless steel plates in between. These experiments are very similar to those documented in LEU-COMP-THERM-062 as both used the same pellet and swaged fuel pin types.

03-GA5=5.164 I Pellet fuel Borated /i

@ Swage fuel stainlessx--

steel Figure 2-20.

Schematic of Arrays with Borated Stainless Steel Plates Page 45

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Of the seventeen experiments reported, all are judged to be acceptable as benchmarks for this validation report. The pellet and swaged fuel pins are identical to those specified in LEU-COMP-THERM-062 in Figure 2-19 of this document.

Five of the experiments were performed with 0.0 wt.% boron stainless steel plates with two different plate thicknesses of 0.2910 and 0.5820 cm. Five were performed with 0.67 wt.% boron stainless steel plates with plate thicknesses of 0.3114 and 0.6228 cm. Five were performed with 0.98 wt.% stainless steel plates with plate thicknesses of 0.3097 and 0.6194 cm. Two experiments were performed with no plates at all. The critical water level height was established for each unique combination of stainless steel plate wt.% boron, plate thickness, spacing between the plate and the rod array cluster and spacing between the rod array cluster and the symmetry plane. Since all fuel pins were of similar composition and size and all lattices were arranged on a 1.9558 cm square pitch, the effective water-to-fuel (W/F) ratio inside the array was -2.1. In addition, the stainless steel and borated stainless steel plate thicknesses are representative of typical spent fuel storage rack cell dimensions and compositions. This makes them suitable for benchmarking BWR reactor lattice configurations inside a spent fuel storage rack geometry.

Tables 2-25, 2-26, 2-27, 2-28, 2-29 and 2-30 provide the material atom densities used for all cases. This data was taken directly from Tables 19, 20, 21, 22, 23 and 24 of Reference 10 with no modification.

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GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Table 2-25. Fuel Rod Atom Densities for LEU-COMP-THERM-065 Isotopic Atom Density (barn-Material Isotope Composition cm) 1 (wt.%)

234u 0.0208 4.8902 x 10-6 23 5 U 2.60 6.0867 x 10- 4 Pellet-type U0 2 2 3 8 U 97.3792 2.2509 x 10-2 O - 4.7076 x 10- 2 234u 0.02064 4.6611 x 10-6 235u 2.58 5.8015 x 10-4 Swage-type UO25 .81 238u U02 97.39936 2.1625 xl0-2 O - 4.4493 x 102 Table 2-26. Atom Density of 6061 Aluminum Alloy Material Element Wt.% Atom Density (barn-cm)-1 Al 97.325 5.8433 x 10-2 Cladding Cr 0.2 6.2310 x 10-5 Cu 0.25 6.3731 x 10.5 Top and bottom end plug Mg 1.0 6.6651 xX 10A Mg 1.0 6.6651 10-4 Upper and lower grid plate Mn 0.075 2.2115 x 10-5 Ti 0.075 2.5375 x 10-5 Zn 0.125 3.0967 x 10-5 3 Si 0.6 3.4607 x 10-4 Density 2.69 g/cm Density_2.69_g_ Fe 0.35 1.0152 x 10-4 Page 47

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Table 2-27. Atom Densities of Stainless Steel Material Element Atom Density cm)-1 (barn-4 C 1.1928 x 10-Si 1.7003 x 10-3 3

Mn 1.7385 x 10-Support plate P 6.9381 X 10-5 S.S.304L (SUS304L) S 4.4673 x 105 Ni 8.9509 x10 3 Cr 1.7450 x 10-2 2

Fe 5.7202 x 10-Table 2-28. Atom Density of Stainless Steel Absorber Plate Material Element wt.% Atom Density (barn-cm)_1 C 0.06 2.3862 x 10- 4 Si 0.45 7.6534 x 10- 4 Stainless Steel Mn 0.83 7.2165 x 10-4 Boron Content P 0.026 4.0096 x 10.5 0 wt.%

Density 7.932 S 0.008 1.1916x 105 g/cm 3 Cr 18.23 1.6747 x 10-2 Ni 8.70 7.0807 x 10-3 Fe 71.696 6.1322 x 10-2 Page 48

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Table 2-29. Atom Density of Borated Stainless Steel Plate (0.67 wt.% boron content)

Material Element Wt.% Atom density (barn-cm)-l C 0.01525 5.9632 x 10-'

Si 0.7275 1.2166 x 10-3 Mn 1.785 1.5260 x 10-3 Stainless steel P 0.0255 3.8666 x 10.5 Boron content S 0.001 1.4645 x 10-6 0.67 wt.% Cr 19.715 1.7808 x 10-2 Density 7.799 Ni 9.955 7.9664 x 10-3 g/cm 3 Mo 0.575 2.8148 x 10-4 4

B0.7 1B 5.7923 x 10-11B 2.3315 x 10-4 Fe 66.53075 5.5951 x 10-2 Table 2-30. Atom Density of Borated Stainless Steel Plate (0.9825 wt.% boron content).

Material Element Wt.% Atom Density (barn-cm)-1 C 0.01 3.9183 x 10-5 Si 0.435 7.2893 x 10-4 Mn 1.6675 1.4285 x 10-3 Stainless Steel P 0.01125 1.7094 x 10-5 Boron Content S 0.00375 5.5031 x 10-6 0.9825wt.% Cr 19.3475 1.7512 x 10- 2 Density Ni 10.1625 8.1492 x 103 7.815 g/cm 3 Mo 0.6 2.9433 x 10-4 B°B.8 8.5113 x 104 3

11B 3.4259 x 10-Fe 66.78 5.6276 x 10- 2 Page 49

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 2.10. Jersey Central Criticals with and without Poison Curtains

((

1]

Er 1]

Figure 2-21.

1/8-Core Symmetry Model of Jersey Central Experiments Page 50

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 11 Figure 2-22.

Jersey Central Bundles and Spacing Page 51

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 r[

11

[II ___________________ _______________________________

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GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 2.11. Small Core Criticals with Burnable Absorbers (KRITZ-75)

Er Er Figure 2-23.

KRITZ-75 Half-Core Symmetry Model Page 53

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 1[

Figure 2-24.

KRITZ-75 Bundle Configuration Page 54

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Er Er_____________ ______________]_

Page 55

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 2.12. NCA Step II& III Criticals Page 56

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 1[

Figure 2-25.

Schematic of the NCA Tank Facility Page 57

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1

[1 11 Figure 2-26.

Schematic of the Step II & III Test Zone Lattices Page 58

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1

((

1]

((

Smeared atom densities are used for consistency with TGBLA.

Page 59

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 rr i i i

+ 4 1]I Page 60

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 rr r

I. .1 Page 61

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 2.13. NCA GNFI Criticals

((I 1]

Page 62

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Er Figure 2-27.

Er 1]

1]

Page 63

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPO1A CriticalBenchmark Evaluations - Revision 1 rr I. I.

I. I-I. I.

Page 64

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1

3. MCNP and the Monte Carlo Method The version of the MCNP Monte Carlo code used in this benchmark validation study is MCNP01A (the GE level 02 version of MCNP4A). MCNP is a generalized Monte Carlo program for solving the linear neutron transport equation as a fixed source or an eigenvalue problem in three space dimensions. It implements the Monte Carlo process for neutron, photon or electron transport, or coupled transport involving all these particles, and can compute the eigenvalue for neutron-multiplying systems. For the present application only neutron transport was considered.

MCNP uses point-wise (i.e., continuous energy) cross section data, and all reactions in a given cross section evaluation (e.g., ENDF/B-V) are considered. For the present work, thermal neutron scattering with hydrogen was described using an S(U,P3) light water thermal scattering kernel. The cross section tables include all details of the ENDF representations for neutron data. The code requires that all the cross-sections be given on a single union energy grid suitable for linear interpolation; however, the cross section energy grid varies from isotope to isotope. The libraries include very little data thinning and utilize maximum resonance integral reconstruction error tolerances of 0.001 %.

MCNP implements a robust geometry representation that can correctly model complex components in three dimensions. An arbitrary three-dimensional configuration is treated as geometric cells bounded by first and second-degree surfaces. The cells are described in a Cartesian coordinate system and are defined by the intersections, unions and complements of the regions bounded by the surfaces. Surfaces are defined by supplying coefficients to the analytic surface equations or, for certain types of surfaces, known points on the surfaces. Rather than combining several pre-defined geometrical bodies in a combinatorial geometry scheme, MCNP has the flexibility of defining geometrical shapes from all the first and second-degree surfaces of analytical geometry and then combining them with Boolean operators. The code performs extensive checking for geometry errors and provides a plotting feature for examining the geometry and material assignments.

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GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1

4. Monte Carlo Simulation Results Prior to discussing the results of the benchmark simulation models, it is appropriate to identify the methods and techniques used by the International Criticality Safety Benchmark Evaluation Project to quantify and evaluate both experimental and calculational uncertainties which can affect a code and cross-section data sets ability to reproduce an observed critical condition.

In each of the ICSBEP benchmark experiments, Section 2.0 (Evaluation of Experimental Data) and Section 3.0 (Benchmark Model Specifications) are included.

These sections describe in detail all of the evaluated experimental uncertainties and their potential impact on the predicted critical eigenvalue via sensitivity studies evaluating each of the most important independent variables of the experiment. The experimental variables evaluated with sensitivity studies are provided in Table 4-1.

The benchmark models used in this study represent the best-estimate representations of each experiment given all the uncertainties analyzed in Table 4-1.

For all ICSBEP benchmark cases, a total of 10,000 neutron histories per batch were executed for a total of 500 batches with the first 50 batches not included in the eigenvalue estimation average. ((

)) In all cases, the MCNP01A output was carefully examined to ensure proper convergence of the fission source before eigenvalue averaging was performed for the final results. In addition, all three eigenvalue estimators (collision, absorption and track length) were confirmed to be normally distributed within the 95% confidence interval.

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GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Table 4 Experimental Variables Evaluated for Sensitivity Studies Experiment Parameter(s) Ak Fuel enrichment, diameter, length, clad thickness, pitch, +0.30%

uranium mass LEU-COMP-THERM-001 Water Reflector thickness < 0.004%

Water temperature +0.005%

Cluster separation 0.04% - 0.09%

Fuel length, plug compression, fuel diameter, pitch, +0.13%

enrichment -0.18%

LEU-COMP-THERM-002 Water Reflector thickness < 0.002%

Water temperature +/-0.04%

Cluster separation 0.01% - 0.04%

Fuel enrichment, density, pellet diameter, clad diameter, +/-0.16%

clad thickness, pitch LEU-COMP-THERM-006 Grid plates, detectors, source < 0.001%

Critical water level height, water temperature 0.01% - 0.08%

Fuel length, pin diameter, pitch, enrichment +/-0.18%

Water Reflector thickness < 0.002%

Water temperature +/-0.04%

LEU-COMP-THERM-009 Cluster separation < 0.011%

Absorber plate separation < 0.013%

Vertical position of absorber plates +0.078%

Absorber plate composition < 0.023%

Absorber plate thickness < 0.013%

Fuel enrichment, diameter, length, clad thickness, pitch, +0.31%

uranium mass -0.30%

Water Reflector thickness < 0.002%

Water impurities < 0.004%

LEU-COMP-THERM-016 Water temperature +/-0.008%

Cluster separation +/-0.001%

Absorber plate separation +0.002%

Absorber plate composition < 0.017%

Absorber plate thickness < 0.002%

Rod array 0.0066%

Absorber plate thickness 0.00257%

LEU-COMP-THERM-034 Absorber plate thickness and composition < 0.00098%

Configuration uncertainties < 0.00206%

Boron impurity in fuel 0.00036%

Impurities in water 0.00005%

LEU-COMP-THERM-039 Fuel enrichment, pin pitch, cladding OD, fuel pin OD, temperature, U02 density, fuel height, moderator height 0.0014%

Enrichment, fuel pin OD, U02 mass, clad thickness, fuel 0.138%

length, pellet OD, lattice pitch, random spacing of larger holes Borated SS plate thickness < 0.004%

LEU-COMP-THERM-062 Borated SS plate B-10 content < 0.009%

Borated SS plate B content < 0.008%

Borated SS plate gap width < 0.056%

Critical water level height < 0.005%

Water temperature < 0.003%

Enrichment, fuel pin OD, U02 mass, clad thickness, fuel 0.132%

length, pellet OD, lattice pitch, random spacing of larger holes Borated SS plate thickness < 0.004%

LEU-COMP-THERM-065 Borated SS plate B-10 content < 0.013%

Borated SS plate B content < 0.006%

Borated SS plate gap width < 0.085%

Critical water level height < 0.005%

Water temperature < 0.003%

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GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 4.1. LEU-COMP-THERM-001 Results The benchmark models for these experiments were created based on the generic MCNP input model provided in Appendix A.2 of LEU-COMP-THERM-001. All of the material composition atom density data used in the models was taken directly from Table 9 of the LEU-COMP-THERM-001 for consistency with the internationally recognized experimental evaluation.

A total of eight experiments were modeled. For the cases involving three pin clusters, the separation distances between the clusters ranged from 4.46 cm to 11.92 cm. The system was full water reflected on all six sides by at least 12 inches of water. All calculations were performed with material and cross-section data representative of the system at 20 0C. The Benchmark model keff was 0.9998+/-0.0031 for these experiments.

Table 4-2 presents the results of the benchmark model comparisons for MCNP using both ENDF/B-V evaluated nuclear data. For all eight cases, the active fuel pin radius of 0.5588 cm and the square lattice pitch of 2.032 cm resulted in an effective (W/F) ratio of 3.209.

Table 4 Benchmark Results for LEU-COMP-THERM-001 Cluster Dim.

Case # Clusters (# Rods) Cluster Separation (cm) Keff + 1c 1 1 20x1 8.08 N/A 2 3 20x17 11.92 3 3 20x16 8.41 4 3 20x16 (center) 10.05 22x16 (outer) 5 3 20x15 6.39 6 3 20x15 (center) 8.01 22x15 (outer) 7 3 20x14 4.46 8 3 19x16 7.57 Page 68

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 4.2. LEU-COMP-THERM-002 Results The benchmark models for these experiments were created based on the generic MCNP input model provided in Appendix A.2 of LEU-COMP-THERM-002. All of the material composition atom density data used in the models was taken directly from the Table 8 of the LEU-COMP-THERM-002 for consistency with the internationally recognized experimental evaluation.

A total of five experiments were modeled. The system was full water reflected on all six sides by at least 12 inches of water. All calculations were performed with material and cross-section data representative of the system at 200C. The Benchmark model keff was 0.9997+/-0.002 for these experiments.

Table 4-3 presents the results. For all five cases, the active fuel pin radius of 0.6325 cm and the square lattice pitch of 1.892 cm resulted in an effective (W/F) ratio of 1.848.

Table 4 Benchmark Results for LEU-COMP-THERM-002 Cluster Dim.

Case # Clusters (# Rods) Cluster Separation (cm) Keff + Ia 1 1 10xl1.51 N/A 2 1 9x13.35 N/A 3 1 8x16.37 N/A 4 3 15x8 10.62 5 3 13x8 7.11 Page 69

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 4.3. LEU-COMP-THERM-006 Results The benchmark models for these experiments were created based on the generic MCNP input model provided in Appendix A.2 of LEU-COMP-THERM-006. All of the material composition atom density data used in the models was taken directly from the Table 14 of the LEU-COMP-THERM-006 for consistency with the internationally recognized experimental evaluation. This data was checked for consistency and is shown as Table 4-4 below.

A total of eighteen experiments were modeled. The system was full water reflected on all six sides by at least 12 inches of water. All calculations were performed with material and cross-section data representative of the system at 200C. The Benchmark model keff was 1.000+/-0.002 for these experiments.

Table 4-4 presents the results. For all eighteen cases, the active fuel pin radius of 0.625 cm was constant but experiments were performed for four different square lattice pitches of 1.849 cm, 19.56 cm, 2.150 cm and 2.293 cm. The corresponding (W/F) ratios are given along with the lattice pitch (cm) and critical water height (Hc) in cm with each result.

Table 4 Benchmark Results for LEU-COMP-THERM-006 Case Pitch Hc Keff + la W/F Case Pitch Hc Keff + la W/F 1 1.849 99.45 0.99598+/-0.00034 1.50 10 2.150 59.96 2.48 2 1.849 73.73 0.99630+/-0.00034 1.50 11 2.150 50.52 2.48 3 1.849 60.81 0.99543+/-0.00036 1.50 12 2.150 44.45 2.48 4 1.956 114.59 0.99580+/-0.00033 1.83 13 2.150 40.44 2.48 5 1.956 75.32 0.99652+/-0.00034 1.83 14 2.293 90.75 3.00 6 1.956 60.38 0.99660+/-0.00035 1.83 15 2.293 64.42 3.00 7 1.956 51.65 0.99668+/-0.00033 1.83 16 2.293 52.87 3.00 8 1.956 46.01 0.99680+/-0.00034 1.83 17 2.293 46.06 3.00 9 2.150 78.67 0.99764+/-0.00033 2.48 18 2.293 41.54 3.00 Page 70

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 4.4. LEU-COMP-THERM-009 Results The benchmark models for these experiments were created based on the generic MCNP input model provided in Appendix A.2 of LEU-COMP-THERM-009. All of the material composition atom density data used in the models was taken directly from the Table 27 of the LEU-COMP-THERM-009 for consistency with the internationally recognized experimental evaluation.

A total of thirteen experiments were modeled. The system was full water reflected on all six sides by at least 12 inches of water. All calculations were performed with material and cross-section data representative of the system at 200C. The Benchmark model keff was 1.000+/-0.0021 for these experiments.

Table 4-5 presents the results. For all thirteen cases, the active fuel pin radius of 0.6325 cm and the square lattice pitch of 1.892 cm resulted in an effective (W/F) ratio of 1.848.

Table 4 Benchmark Results for LEU-COMP-THERM-009 Plate Thks. Distance to Center Cluster Separation Case Plate Type (mm) Cluster (mm) (mm) Keff + la 1 0% B 4.85+0.15 2.45+0.33 85.8+0.2 2 0% B 4.85+0.15 32.77+0.32 96.5+0.4 3 0% B 3.02+0.13 4.28+0.32 92.2+0.1 4 0% B 3.02+0.13 32.77+0.32 97.6+0.3 5 1.05% B 2.98+0.06 4.32+0.30 61.0+0.1 6 1.05% B 2.98+0.06 32.77+0.32 80.8+0.2 7 1.62% B 2.98+0.05 4.32+0.30 57.6+0.2 8 1.62% B 2.98+0.05 32.77+0.32 79.0+0.3 9 Boral 7.13+0.11 32.77+0.32 67.2+0.1 24 Al 6.25+0.01 1.05+0.29 107.2+0.1 25 Al 6.25+0.01 32.77+0.32 107.7+0.5 26 Zr-4 6.52+0.08 0.78+0.30 109.2+0.4 27 Zr-4 6.52+0.08 32.77+0.32 108.6+0.4 Page 71

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA Critical Benchmark Evaluations - Revision 1 4.5. LEU-COMP-THERM-016 Results The benchmark models for these experiments were created based on the generic MCNP input model provided in Appendix A.2 of LEU-COMP-THERM-016. All of the material composition atom density data used in the models was taken directly from the Tables 34, 35, 36 and 37 of LEU-COMP-THERM-016 for consistency with the internationally recognized experimental evaluation.

A total of twenty experiments were modeled. The system was full water reflected on all six sides by at least 12 inches of water. All calculations were performed with material and cross-section data representative of the system at 200C. The Benchmark model keff was 1.000+/-0.0031 for these experiments.

Table 4-6 presents the results. For all twenty cases, the active fuel pin radius of 0.5588 cm and the square lattice pitch of 2.032 cm resulted in an effective (W/F) ratio of 3.209.

Table 4 Benchmark Results for LEU-COMP-THERM-016 Plate Plate Thks. Distance to Center Cluster Case Type (mm) Cluster (mm) Separation (mm) Keff+ la 1 Steel 0%B 4.85+0.15 6.45+0.06 68.8+0.2 [

2 Steel 0%B 4.85+0.15 27.32+0.5 76.4+0.4 3 Steel 0%B 4.85+0.15 40.42+0.7 75.1+0.3 4 Steel 0%B 3.02+0.13 6.45+0.06 74.2+0.2 5 Steel 0%B 3.02+0.13 40.42+0.7 77.6+0.3 6 Steel 0%B 3.02+0.13 6.45+0.06 104.4+0.3 7 Steel 0%B 3.02+0.13 40.42+0.7 114.7+0.3 8 Steel 1.05%B 2.98+0.06 6.45+0.06 75.6+0.2 9 Steel 1.05%B 2.98+0.06 40.42+0.7 96.2+0.3 10 Steel 1.62%B 2.98+0.05 6.45+0.06 73.6+0.3 11 Steel 1.62%B 2.98+0.05 40.42+0.7 95.2+0.3 12 Boral 7.13+0.11 6.45+0.06 63.3+0.5 13 Boral 7.13+0.11 44.42+0.60 90.3+0.5 14 Boral 7.13+0.11 6.45+0.06 50.5+0.3 18 Copper 3.37+0.08 6.45+0.06 68.8+0.5 28 Al 6.25+0.01 6.45+0.06 86.7+0.3 29 Al 6.25+0.01 40.42+0.7 87.8+0.3 30 Al 6.25+0.01 44.42+0.60 88.3+0.3 31 Zircaloy 6.52+0.08 6.45+0.06 87.9+0.3 32 Zircaloy 6.52+0.08 40.42+0.7 87.8+0.4 Page 72

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 4.6. LEU-COMP-THERM-034 Results The benchmark models for these experiments were created based on the generic MCNP input model provided in Appendix A.2 of LEU-COMP-THERM-034. All of the material composition atom density data used in the models was taken directly from the Tables 13 and 14 of the LEU-COMP-THERM-034 for consistency with the internationally recognized experimental evaluation.

A total of fourteen experiments were modeled. The system was full water reflected on all six sides by at least 12 inches of water. All calculations were performed with material and cross-section data representative of the system at 201C. The Benchmark model keff was 1.000 for these experiments. The uncertainty ranged from 0.0039 to 0.0048 Table 4-7 presents the results of the benchmark calculations. For all fourteen cases, the active fuel pin radius of 0.395 cm and the square lattice pitch of 1.60 cm resulted in an effective (W/F) ratio of 4.223.

Table 4 Benchmark Results for LEU-COMP-THERM-034 Case Canister Water Gap (cm) Critical Water Height (cm) Ke + l0 1 Borated Steel 0.6 34.33+0.06 2 Borated Steel 1.0 36.54+0.06 3 Borated Steel 2.0 41.40+0.08 4 Borated Steel 3.0 47.15+0.07 5 Borated Steel 4.0 53.87+0.07 6 Borated Steel 5.0 62.86+0.08 7 Borated Steel 6.0 70.73+0.06 8 Borated Steel 7.0 80.66+0.06 10 Boral 0.3 50.74+0.06 11 Boral 0.5 53.01+0.06 12 Boral 1.0 57.43+0.06 13 Boral 1.5 66.15+0.06 14 Boral 2.0 72.96+0.06 15 Boral 2.5 84.15+0.07 Page 73

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 4.7. LEU-COMP-THERM-039 Results The benchmark models for these experiments were created based on the information provided in Appendix A.2 of LEU-COMP-THERM-039. All of the material composition atom density data used in the models was taken directly from the Table 9 of the LEU-COMP-THERM-039 for consistency with the internationally recognized experimental evaluation.

A total of seventeen experiments were modeled. The system was full water reflected on all six sides by at least 12 inches of water. All calculations were performed with material and cross-section data representative of the system at 200C. The Benchmark model keff was 1.000+/-0.0014 for these experiments.

Table 4-8 presents the results of the benchmark calculations. For all seventeen cases, the active fuel pin radius of 0.395 cm and the square lattice pitch of 1.26 cm were held constant. However, different combinations of rods were removed from the array resulting a variety of effective (W/F) ratios for the tests. The (W/F) ratios are given for each case in Table 4-8.

Table 4 Benchmark Results for LEU-COMP-THERM-039 Case # Rods # Holes Critical Water Height (cm) WIF Kef + l0 1 459 25 81.36+0.07 2.415 2 448 36 77.69+0.06 2.499 3 420 64 73.05+0.06 2.732 4 392 49 89.07+0.06 2.644 5 320 121 84.37+0.06 3.464 6 363 121 58.77+0.06 3.319 7 459 25 69.71+0.06 2.415 8 448 36 66.79+0.06 2.499 9 448 36 64.47+0.06 2.499 10 420 64 58.37+0.06 2.732 11 459 25 81.34+0.06 2.415 12 459 25 75.38+0.07 2.415 13 459 25 72.52+0.06 2.415 14 459 25 71.14+0.06 2.415 15 459 25 69.88+0.06 2.415 16 459 25 69.40+0.06 2.415 17 459 25 68.75+0.06 2.415 Page 74

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 4.8. LEU-COMP-THERM-062 Results The benchmark models for these experiments were created based on the generic MCNP input model provided in Appendix A.2 of LEU-COMP-THERM-062. All of the material composition atom density data used in the models was taken directly from the Tables 19, 20, 21, 22, 23 and 24 of the LEU-COMP-THERM-062 for consistency with the internationally recognized experimental evaluation.

A total of fifteen experiments were modeled. The system was full water reflected on all six sides by at least 12 inches of water. All calculations were performed with material and cross-section data representative of the system at 200C. The Benchmark model keff was 1.000+/-0.0016 for these experiments.

Table 4-9 presents the results of the benchmark calculations. For all fifteen cases, the active fuel pin radius of 0.6251 cm and the square lattice pitch of 1.956 cm resulted in an effective (W/F) ratio of 2.116.

Table 4 Benchmark Results for LEU-COMP-THERM-062 Critical Water Gap Width Plate Thks.

Case Height (cm) (cm) (cm) Boron (wt.%) Kff + la 1 80.89 0 N/A N/A 2 89.78 0 0.2910 0 3 92.68 0 0.5820 0 4 89.85 0.9779 0.5820 0 5 86.42 1.9558 0.5820 0 6 111.50 0 0.3114 0.67 7 112.71 0 0.6228 0.67 8 104.14 0.9779 0.3114 0.67 9 98.74 0.9779 0.6228 0.67 10 96.51 1.9558 0.3114 0.67 11 92.31 1.9558 0.6228 0.67 12 112.81 0 0.3097 0.98 13 116.40 0 0.6194 0.98 14 104.77 0.9779 0.6194 0.98 15 95.55 1.9558 0.6194 0.98 Page 75

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPO1A CriticalBenchmark Evaluations - Revision 1 4.9. LEU-COMP-THERM-065 Results The benchmark models for these experiments were created based on the generic MCNP input model provided in Appendix A.2 of LEU-COMP-THERM-065. All of the material composition atom density data used in the models was taken directly from the Tables 19, 20, 21, 221 23 and 24 of the LEU-COMP-THERM-065 for consistency with the internationally recognized experimental evaluation.

A total of fifteen experiments were modeled. The system was full water reflected on all six sides by at least 12 inches of water. All calculations were performed with material and cross-section data representative of the system at 20 0 C. The Benchmark model keff ranged from 0.9994 to 1.0005 for these experiments. The uncertainty ranged from 0.0014 to 0.0017.

Table 4-10 presents the results of the benchmark calculations. For all seventeen cases, the active fuel pin radius of 0.6251 cm and the square lattice pitch of 1.956 cm resulted in an effective (W/F) ratio of 2.116.

Table 4 Benchmark Results for LEU-COMP-THERM-065 Case Crticial Water Gap Width Distance Plate Thks. Boron Keff + lo Level (cm) (cm) (cm) (cm) (wt.%)

1 50.62 N/A 2.9337 N/A N/A 2 61.56 0 2.9337 0.5820 0 3 81.01 0 2.9337 0.6228 0.67 4 84.44 0 2.9337 0.6194 0.98 5 57.94 N/A 3.9116 N/A N/A 6 65.26 0 3.9116 0.2910 0 7 64.20 0.9779 3.9116 0.2910 0 8 68.98 0 3.9116 0.5820 0 9 66.51 0.9779 3.9116 0.5820 0 10 86.20 0 3.9116 0.3114 0.67 11 78.18 0.9779 3.9116 0.3114 0.67 12 88.73 0 3.9116 0.6228 0.67 13 77.95 0.9779 3.9116 0.6228 0.67 14 90.82 0 3.9116 0.3097 0.98 15 80.22 0.9779 3.9116 0.3097 0.98 16 93.02 0 3.9116 0.6194 0.98 17 80.65 0.9779 3.9116 0.6194 0.98 Page 76

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 4.10. Jersey Central Criticals with and without Poison Curtains Er Table 4 Benchmark Results for Jersey Central Small Core Criticals Er Page 77

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 4.11. Small Core Criticals with Burnable Absorbers (KRITZ-75) 11 Table 4 Benchmark Results for KRITZ-75 Small Core Criticals Er Page 78

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 4.12. NCA Step II & Step III Criticals

((

Table 4 Benchmark Results for NCA Step II & Step III Criticals ER Page 79

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 4.13. NCA GNF1 Criticals

[U Table 4 Benchmark Results for NCA GNF1 Criticals

((

[F i i i i i j 1- 4 I. 4 4 F 4 4 4 4 F F

+ 4 F 4 4 4 F F I I I I F F

+ 4 F F 4 4 4 F F

+/- F F 4 4 4 F F I I I I F F

+ 4 F F 4 4 4 F F

+/- 4 F F I I I F F 4- 4 F F 4 4 4 F F I F F I I I F F

+ 4 F F 4 4 4 F F Page 80

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 11 Fe Figure 4 NCA GNF1 Experiments with 5 mm Aluminum Spacer Page 81

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Er Figure 4 ((

Page 82

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Er Er Figure 4 Axial Gamma Scan Comparison for Rod A Er Page 83

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision' 1

[1 11 Figure 4 ((

Page 84

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 1[

Figure 4 ((

Page 85

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1

((l Page 86

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 rE Figure 4 ((

Er

[E Page 87

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 1r 1]

Figure 4 ((

Page 88

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 11 Figure 4 ((

1[

Page 89

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPO1A CriticalBenchmark Evaluations - Revision 1

((

Figure 4 (( '

E[

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GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1

((

))

Figure 4 (( I))

Er Page 91

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1

[r Figure 4 ((

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Page 92

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1

5. Statistical Analysis of Results 5.1. MCNP01A Results as an Individual Population Sample Figure 5-1 shows the results of a statistical analysis of all 190 benchmark eigenvalues treated as a single population sample with no correlation to any particular independent variable.

Figure 5-1.

MCNP01A Results Treated as a Single Population Sample Page 93

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 As can be seen from the results in Figure 5-1, the population sample has a mean value (( )). Ifwe state that the null hypothesis (H,) is that the mean (t) of the sample data is constant, then the alternative hypothesis (Ha) would be that the mean (ii) is not constant. ((

))

In the following sections a sensitivity of the eigenvalue results will be performed to several independent correlation variables which are known to influence the reactivity of .the critical systems under consideration. Examples of such variables would be effective water-to-fuel (W/F) ratio, absorber plate thickness and effective gadolinium rod wt% loading of the fuel pins. Sections 5.2 through 5.4 will consider these effects.

Page 94

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 5.2. MCNPOIA Eigenvalues Correlated to W/F Ratio Figure 5-2 show the results of the MCNP01A eigenvalue calculations for all 190 experimental benchmark cases as a function of water-to-fuel (W/F) ratio for each experiment. The (W/F) ratio was chosen as the independent correlation variable since it is common to all experiments and affects the relative degree of moderation within the lattice.

Figure 5-2.

MCNP01A Resutls as a Function of W/F Ratio Page 95

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPO1A CriticalBenchmark Evaluations - Revision 1 Er 1]

5.3. MCNPOIA Eigenvalues for Absorber Plate Sytems An alternative way of evaluating the results of the MCNP01A benchmark calculations is to group only those experiments that contained absorber plates between array clusters (to simulate storage rack conditions). These experiments include LEU-COMP-THERM-009, 016, 034, 062 and 065 (seventy-nine experiments in all). A normality test of this data is shown in Figure 5-3 below.

((

Figure 5-3. Results for Absorber Plate Criticals Only Page 96

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations -. Revision 1 EE 1]

Er Figure 5-4 Results for Absorber Plate Criticals as a Function of W/F Ratio Er Er Page 97

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Er 1]

Figure 5-5.

Results for Absorber Plate Criticals as a Function of Plate Thickness Er Page 98

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 5.4. MCNPO1A Eigenvalues for Gadolinium Systems Er E))

Figure 5-6.

Results for NCA Step II, Step Ill and GNF1 Criticals with Gd 203 Page 99

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPO1A CriticalBenchmark Evaluations - Revision 1

((

Figure 5-7.

Results Correlated to the Number of Gd Rods in Each Test Zone Lattice Page 100

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPO1A CriticalBenchmark Evaluations - Revision 1

[II

[II Figure 5-8.

Results Correlated to the Number of Gd Rods in Each Test Zone Lattice Page 101

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1

6. Bias and Bias Uncertainty In order to account for the uncertainty in the experimental values (Reference 16), the weighted sample mean and standard deviation were calculated using the following equations:

B = Measured Kesi - Calculated(MCNPO1A) Keff Equation 1

n. Bi z2 i=l 0"i2 Equation 2 SP - S 2 + 6:2 Equation 3

--2 n 12 Equation 4 22 Equation 5 1 U12 n i=1 i Where:

Page 102

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 fB = Average weighted bias in Keff

= Uncertainty in bias Bi Sp = Pooled standard deviation 2

S = Variance about the mean a= Average total variance n = number of data points (=190)

Using the average weighted bias and pooled standard deviation; the upper one-sided 95/95-tolerance limit (Reference 17) and the bias uncertainty were calculated for use in criticality calculations. Table 6-1 summarizes the results of these calculations.

Table 6 Bias and Bias Uncertainty Results for MCNP01A with ENDF/B-V 11 Bias=Benchmark-MCNPO1 A

7. Conclusions/Recommendations The 190 experimental benchmark data set studied in this report adequately simulates the lattice physics characteristics of typical BWR fuel lattices. The experimental range of W/F ratio extends from -0.8 up to 4.2 for low-enriched U02 pin lattice in water systems. All of the experiments considered are judged to be acceptable as benchmark experiments either by virtue of their inclusion in Reference 3 (previously Page 103

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 accepted by the International Benchmark Evaluation Group) or by their historical use within the BWR nuclear fuels community.

The data is judged to be acceptable for the determination of code and cross-section data set bias and bias uncertainty for application to spent fuel storage rack criticality safety analysis as well as for the purposes of lattice physics benchmaking of other transport method codes. ((

The recommended bias and bias uncertainty to be used with criticality analyses are shown in Table 7-1.

Table7-1: Recommended Bias and Bias Uncertainty in Criticality Analyses for MCNP01A with ENDF/B-V Er Page 104

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1

8. References

1. MCNP4A - "Monte Carlo N-Particle Code System", Los Alamos Nat. Lab.,

Distributed by RSIC, CCC-200, December 1993.

2. MCNP01A; General Electric version of Los Alamos National Laboratory code, MCNP4A - General Monte Carlo N-Particle Transport Code, DRF J1 1-02538, March, 1995.

3. International Criticality Safety Benchmark Evaluation Project (ICSBEP), LEU-COMP-THERM-001 - 063, Benchmark Experiments, September 2005. ,

4. S.R. Bierman, E.D. Clayton and B.M. Durst, "Critical Separation Between Subcritical Clusters of 2.35 wt.% Enriched U0 2 Rods in Water with Fixed Neutron Poisons", PNL-2438, Battelle Pacific Northwest Laboratories, Richland, Washington, October 1977.

5. S.R. Bierman and E.D. Clayton, "Criticaltiy Experiments with Subcritical Clusters of 2.35 wt.% and 4.31 wt.% Enriched U0 2 Rods in Water at a Water-to-Fuel Volume Ratio of 1.6", NUREG/CR-1547, PNL-3314, Battelle Pacific Northwest Laboratories, Richland, Washington, July 1980.

6. S.R. Bierman, B.M. Durst and E.D. Clayton, "Critical Separation Between Subcritical Clusters of 4.29 wt.% 235 U Enriched U0 2 Rods in Water with Fixed Neutron Poisons", NUREG/CR-0073, Battelle Pacific Northwest Laboratories, Richland, Washington, May 1978.

7. Harumichi Tsuruta, Iwao Kobayashi, Takenori Suzaki, Akio Ohno, Kiyonobu Murakami and Syojiro Matsuura, "Critical Sized of Light Water Moderated U0 2 and PuO 2-UO 2 Lattices", JAERI-1254, 1978.

8. J.C. Manaranche, D. Mangin, L. Maubert, G. Colomb, G. Poullot, "Experimental Studies of LWR Fuel Rods in Various Configurations",

Rappaport DSN, 399/80, December 1980.

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9. J.C. Manaranche, D. Mangin, L. Maubert, G. Colomb, G. Poullot, "Critical Experiments with Lattices of 4.75 wt.% U-235 Enriched U0 2 Rods in Water",

Nucl. Sci. & Eng., Vol. 71, pp. 143-163, 1979.

10. Yoshinori Miyoshi, Ken Nakajima, Masanori Akia, Akio Ohno, Iwao Kobayashi, Shigeaki Aoki, Masayuki Harada, Chirio Hondo and Ichiro Deguchi, "Reactivity Effects of Borated Steel Plate in Single and Coupled Cores Composed of Low-Enriched U0 2 Rods", Journal of Nuclear Science and Technology, Vol. [3114, pp. 335-348, 1994.

11.C.L. Martin, "Lattice Physics Methods Verification", GE Nuclear Energy, NEDO-20939, Class I, June 1976.

12.S. Sitaraman,"MCNP: Light Water Reactor Critical Benchmarks", GE Nuclear Energy, NEDO-32028, Class I, March 1992.

13.Persson, R. and Johansson, E., "KRITZ BA-75: Critical High Temperature Experiments on BWR Assemblies with Burnable Absorbers - August-December 1975," AB Atomenergi Sweden, AE-RF-76-4154, February 1976 (English Translation October 1976).

14.Y. Karino, "MCNP:TGBLA03/DIF3D:TGBLA06V/DIF3D Benchmarking of Toshiba's NCA Critical Facility", GE Nuclear Energy, NEDC-32609P, Class Ill, May 1996.

15.SCO-01-2047, "2001 Critical Examination of PLR/Corner Gad", Toshiba Electric Power Corporation, December 2001.

16.NUREG/CR-6698 "Guide For Validation of Nuclear Criticality Safety Calculational Methodology", Science Applications International Corporation, January 2001.

17. NIST/SEMATECH e-Handbook of Statistical Methods, http://www.itl.nist.gov/div898/handbook/prc/section2/prc263.htm, 2006 Page 106

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 Appendix: MCNP01A Benchmark Results Experiment Expt. # Benchmark Eievle Experimental Ucrany MCNP01A MCNP01A Bias* Bias Eigenvalue Uncertainty Uncertainty Uncertainty 1 LEU-COMP-THERM-001 1 0.9998 0.0031 ((

2 LEU-COMP-THERM-001 2 0.9998 0.0031 3 LEU-COMP-THERM-001 3 0.9998 0.0031 4 LEU-COMP-THERM-001 4 0.9998 0.0031 5 LEU-COMP-THERM-001 5 0.9998 0.0031 6 LEU-COMP-THERM-001 6 0.9998 0.0031 7 LEU-COMP-THERM-001 7 0.9998 0.0031 8 LEU-COMP-THERM-001 8 0.9998 0.0031 9 LEU-COMP-THERM-002 1 0.9997 0.002 10 LEU-COMP-THERM-002 2 0.9997 0.002 11 LEU-COMP-THERM-002 3 0.9997 0.002 12 LEU-COMP-THERM-002 4 0.9997 0.002 13 LEU-COMP-THERM-002 5 0.9997 0.002 14 LEU-COMP-THERM-006 1 1 0.002 15 LEU-COMP-THERM-006 2 1 0.002 16 LEU-COMP-THERM-006 3 1 0.002 17 LEU-COMP-THERM-006 4 1 0.002 18 LEU-COMP-THERM-006 5 1 0.002 19 LEU-COMP-THERM-006 6 1 0.002 20 LEU-COMP-THERM-006 7 1 0.002 21 LEU-COMP-THERM-006 8 1 0.002 22 LEU-COMP-THERM-006 9 1 0.002 23 LEU-COMP-THERM-006 10 1 0.002 24 LEU-COMP-THERM-006 11 1 0.002 25 LEU-COMP-THERM-006 12 1 0.002 Page 107

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 26 LEU-COMP-THERM-006 13 1 0.002 27 LEU-COMP-THERM-006 14 1 0.002 28 LEU-COMP-THERM-006 15 1 0.002 29 LEU-COMP-THERM-006 16 1 0.002 30 LEU-COMP-THERM-006 17 1 0.002 31 LEU-COMP-THERM-006 18 1 0.002 32 LEU-COMP-THERM-009 1 1 0.0021 33 LEU-COMP-THERM-009 2 1 0.0021 34 LEU-COMP-THERM-009 3 1 0.0021 35 LEU-COMP-THERM-009 4 1 0.0021 36 LEU-COMP-THERM-009 5 1 0.0021 37 LEU-COMP-THERM-009 6 1 0.0021 38 LEU-COMP-THERM-009 7 1 0.0021 39 LEU-COMP-THERM-009 8 1 0.0021 40 LEU-COMP-THERM-009 9 1 0.0021 41 LEU-COMP-THERM-009 24 1 0.0021 42 LEU-COMP-THERM-009 25 1 0.0021 43 LEU-COMP-THERM-009 26 1 0.0021 44 LEU-COMP-THERM-009 27 1 0.0021 45 LEU-COMP-THERM-016 1 1 0.0031 46 LEU-COMP-THERM-016 2 1 0.0031 47 LEU-COMP-THERM-016 3 1 0.0031 48 LEU-COMP-THERM-016 4 1 0.0031 49 LEU-COMP-THERM-016 5 1 0.0031 50 LEU-COMP-THERM-016 6 1 0.0031 51 LEU-COMP-THERM-016 7 1 0.0031 52 LEU-COMP-THERM-016 8 1 0.0031 53 LEU-COMP-THERM-016 9 1 0.0031 54 LEU-COMP-THERM-016 10 1 0.0031 Page 108

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 55 LEU-COMP-THERM-016 11 1 0.0031 56 LEU-COMP-THERM-016 12 1 0.0031 57 LEU-COMP-THERM-016 13 1 0.0031 58 LEU-COMP-THERM-016 14 1 0.0031 59 LEU-COMP-THERM-016 18 1 0.0031 60 LEU-COMP-THERM-016 28 1 0.0031 61 LEU-COMP-THERM-016 29 1 0.0031 62 LEU-COMP-THERM-016 30 1 0.0031 63 LEU-COMP-THERM-016 31 1 0.0031 64 LEU-COMP-THERM-016 32 1 0.0031 65 LEU-COMP-THERM-034 1 1 0.0047 66 LEU-COMP-THERM-034 2 1 0.0047 67 LEU-COMP-THERM-034 3 1 0.0039 68 LEU-COMP-THERM-034 4 1 0.0039 69 LEU-COMP-THERM-034 5 1 0.0039 70 LEU-COMP-THERM-034 6 1 0.0039 71 LEU-COMP-THERM-034 7 1 0.0039 72 LEU-COMP-THERM-034 8 1 0.0039 73 LEU-COMP-THERM-034 10 1 0.0048 74 LEU-COMP-THERM-034 11 1 0.0048 75 LEU-COMP-THERM-034 12 1 0.0048 76 LEU-COMP-THERM-034 13 1 0.0048 77 LEU-COMP-THERM-034 14 1 0.0043 78 LEU-COMP-THERM-034 15 1 0.0043 79 LEU-COMP-THERM-039 1 1 0.0014 80 LEU-COMP-THERM-039 2 1 0.0014 81 LEU-COMP-THERM-039 3 1 0.0014 82 LEU-COMP-THERM-039 4 1 0.0014 83 LEU-COMP-THERM-039 5 1 0.0014 Page 109

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 84 LEU-COMP-THERM-039 6 1 0.0014 85 LEU-COMP-THERM-039 7 1 0.0014 86 LEU-COMP-THERM-039 8 1 0.0014 87 LEU-COMP-THERM-039 9 1 0.0014 88 LEU-COMP-THERM-039 10 1 0.0014 89 LEU-COMP-THERM-039 11 1 0.0014 90 LEU-COMP-THERM-039 12 1 0.0014 91 LEU-COMP-THERM-039 13 1 0.0014 92 LEU-COMP-THERM-039 14 1 0.0014 93 LEU-COMP-THERM-039 15 1 0.0014 94 LEU-COMP-THERM-039 16 1 0.0014 95 LEU-COMP-THERM-039 17 1 0.0014 96 LEU-COMP-THERM-062 1 1 0.0016 97 LEU-COMP-THERM-062 2 1 0.0016 98 LEU-COMP-THERM-062 3 1 0.0016 99 LEU-COMP-THERM-062 4 1 0.0016 100 LEU-COMP-THERM-062 5 1 0.0016 101 LEU-COMP-THERM-062 6 1 0.0016 102 LEU-COMP-THERM-062 7 1 0.0016 103 LEU-COMP-THERM-062 8 1 0.0016 104 LEU-COMP-THERM-062 9 1 0.0016 105 LEU-COMP-THERM-062 10 1 0.0016 106 LEU-COMP-THERM-062 11 1 0.0016 107 LEU-COMP-THERM-062 12 1 0.0016 108 LEU-COMP-THERM-062 13 1 0.0016 109 LEU-COMP-THERM-062 14 1 0.0016 110 LEU-COMP-THERM-062 15 1 0.0016 111 LEU-COMP-THERM-065 1 1 0.0014 112 LEU-COMP-THERM-065 2 0.9999 0.0014 Page 110

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 113 LEU-COMP-THERM-065 3 0.9996 0.0015 114 LEU-COMP-THERM-065 4 0.9997 0.0015 115 LEU-COMP-THERM-065 5 1 0.0014 116 LEU-COMP-THERM-065 6 0.9998 0.0014 117 LEU-COMP-THERM-065 7 0.9991 0.0014 118 LEU-COMP-THERM-065 8 1 0.0016 119 LEU-COMP-THERM-065 9 1.0001 0.0015 120 LEU-COMP-THERM-065 10 1.0002 0.0016 121 LEU-COMP-THERM-065 11 1.0005 0.0016 122 LEU-COMP-THERM-065 12 1 0.0017 123 LEU-COMP-THERM-065 13 1.0001 0.0016 124 LEU-COMP-THERM-065 14 1.0003 0.0016 125 LEU-COMP-THERM-065 15 0.9994 0.0016 126 LEU-COMP-THERM-065 16 0.9998 0.0017 127 LEU-COMP-THERM-065 17 1.0003 0.0016 128 129 130 131 132 133 134 135 136 137 138 139 140 141 Page 111

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPOIA CriticalBenchmark Evaluations - Revision 1 142 143 144 I I 4 4 4 4 145

- 4 4 4. .4 I. I. I. I-146 4 4 4 4 I. I. I I 147 148 1 *4 I 4 149 4 4 4. 4 I. I. I. I.

150 151

-1 1 I- 4 4* I.

152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 Page 112

GNF Non-proprietary Information - Class I 0000-0032-0998-R2 MCNPO1A CriticalBenchmark Evaluations - Revision 1 171

.4 .4 .4 I. I. 4 172 173 I I 4. 4.

174

.4 .4 4. .4 4. 4. 4. 4.

175

- .4 .4 I. .4 4. I. 4. 4.

176 177

- 1 ~4 4. 4. 4. 4. 4.

178

.4 4 4. .4 I. I. I. 4 179 180 181 I 4 .4 4. 4. 4. 4.

182

- 4 .4 4. .4 I. 4. 4. 4.

183 184

- 1 1 4. ~4 4. 4. 4. 4.

185

- 4 4 4. .4 4. 4. 4. 4.

186 187 188 189 190 Bias= Bench mark-M CNPO 1A Page 113

ML102170185

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