ML061640239

Tn Calculation 1121-0504, Revision 1, OS197L 75 Ton Transfer Cask Dose Rates; Calculation to Be Used with OPPD Exemption Request.

ML061640239
Person / Time
Site:	Fort Calhoun, 07201004
Issue date:	06/07/2006
From:	Axline J, Gardner S, Kinsman D Transnuclear
To:	Office of Nuclear Reactor Regulation
References
1121-012, LIC-06-056 1121-0504, Rev 1
Download: ML061640239 (13)

Text

LIC-06-056 Page 1 TN Calculation 1121-0504, Revision 1, 0S197L 75 Ton Transfer Cask Dose Rates Calculation to be used with OPPD Exemption Request

A or .21Calculation No.: 1121 -0504 AtiARVACop~rfRevision No.: I CALCULATION TITLE: Page: I of 12 0S197L 75 Ton Transfer Cask Dose Rate Calculation to be Project No.: 1121 Used With OPPD Exemption Request DCR No.: 1121-012 PROJECT NAME, Fort Calhoun Station Spent Fuel Storage Project Number of CDs attached: I If original Issue, Is licensing review per TIP 3.6 required?

0 No (explain) 0yes Licensing Review No.:_________

This-calculation determines the radiation dose rates around the 08197L TC In support of an exemption request by OPPD to be submitted to the NRC. OPPD is planning to load the NUHOMSO -32PT DSC using the 08197L Transfer Cask. These configurations are NOT the design basis for the NUHOMS0 -32PT System. Therefore, a 72.48 licensing review per TIP 3.5 Is not required.

Software Utililzed: Version:

MCNP5 1.2 MCNP5 (Limited Use Software) 1.4 No new MCNP5 calculations are performned In this revision I Calculation Is complete:.

Shane Gardner Originator Sip nature: Date: 06/07/2006 Calculation has been checked for consistency, completeness and correctness:

Checer Sgnatre:Date: 06/07/2006 James Axilne Project Engineer Signazrew Date

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SUMMARY

ESCIPTONAFFECTED AFFECTED REV DAE REV DAE ESCIPTONPAGES DISKS Initial issue Sumry Dfescripion:~ The 0S1 97L-75 is a general purpose, light weight (75 Tons) on-site Transfer Cask (TC). A detailed shielding evaluation of the OSI1 97L TC with various configurations is performed in Calculation NUHO6L-0500 at normal and accident conditions. This calculation is prepared to 0 06/01/06 document radiation dose rate calculations in 121 support of an exemption request by OPPRD to be submitted to the NRC for review and approval. OPPD is planning to load the NUHOMS'-32PT DSC using the 051 97L Transfer Cask.

Above all, this calculation is NOT a design basis or a licensing basis calculation for either the 0S1 97L TC or the NUHOMSe 32PT DSC.

This revision deletes all information pertaining bare TC with 18.4 kW/DSC evaluation. All 0ýtoThethedesign basis axial dose rate is added.

_____________Other minor editorial corrections are made. ______

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1. PURPOSE ............................................................................... 4

2. REFERENCES .......................................................................... 4 2.1 Referenced Documents, Calculations, Publications etc. 4 2.2 List of Acronyms and Conventions 5

3. METHODOLOGY AND DESIGN INPUTS............................................. 5 3.1 Methodology 5 3.2 Design Inputs 6

4. ASSUMPTIONS AND CONSERVATISMVS............................................ 6

5. CALCULATIONS........................................................................ 7 5.1 Use of MCNP5 Software 7 5.2 MCNP5 Models 7

6. RESULTS...................................................... ........

"*--*8 6.1 Axial Dose Rates for the Design Basis Fuel Loading 8 6.2 Radial Dose Rates for the Design Basis Fuel Loading 8

7.

SUMMARY

AND CONCLUSIONS.................................................... 10

8. APPENDIX A, FILE LISTING.......................................................... 11 8.1 MCNP Runs 11 8.2 Miscellaneous Spreadsheets 12 LIST OF TABLES Table 6-1 Axial DSC Top Welding Dose Rates for 051 97L 8 Table 6-2 Maximum of Total, Gamma +Neutron, Radiation Dose Rates (Averaged over angular Coordinate) at Different Radial Distances from Side of Decon Shield Sleeve 9

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1. PURPOSE The purpose of this summary calculation is to calculate the radiation dose rates around the 0S197L Transfer Cask (TC) with a fully loaded NUHOMSO 32PT DSC containing 32 design basis B&W 15x1 5 PWR fuel assemblies. A comprehensive shielding evaluation for the OS197L TC with a variety of shielding configurations is documented in reference [2]. This calculation provides the radiation dose rates as a function of distance from the TC surface for a specific configuration not described in reference [2].

The evaluation is based on the 0S 197L cask under normal conditions, when the OS197L cask is inside the decon sleeve, with shield bell, with the neutron shield full and water in the DSCITC annulus. The radiation dose rates (radial) as a function of distance for the NUHOMSO 32PT with design basis (24 kW/DSC) fuel assemblies are determined in this evaluation. The axial dose rate applicable to technical specification limits is also determined. This calculation is NOT a design basis or licensing basis calculation for either the OS197L TC or the NUHOMSO 32PT DSC.

2. REFERENCES 2.1 Referenced Documents, Calculations, Publications etc.

1. UFSAR "Standardized NUHOMSO Horizontal Modular Storage System for Irradiated Nuclear Fuel", NUH-003 Rev. 9.

2. Transnuclear Calculation NUHO6L-0500, Revision 1, "Design of Integral Radiation Shield for On-Site Transfer Cask 0S197-L and Calculation of Occupational Exposure due to 32PT DSC Design Basis Fuel."

3. Transnuclear Calculation 1121-0500, Revision 3, "OPPD ISFSI Phase I through Phase IV Dose Rates and Annual Exposure Calculation."

4. MCNP - A General Monte Carlo N-Particle Transport Code, Version 5, Volume II:

Users Guide, LA-CP-03-0245, 2003.

5. MCNP5 vi1.20 Computer Code Verification Record. Test Plan: TN File No. QA 040.230.0001, Test Report: TN File No. QA 040.230.0002.

6. "MCNP/MCNPX - Monte Carlo N-Particle Transport Code System Including MCNP5 1.40 and MCNPX 2.5.0 and Data Libraries," CCC-730, Oak Ridge National Laboratory, RSICC Computer Code Collection, January 2006.

7. Transnuclear Calculation NUH32PT.0501, Revision 0, i"NUHOMSe0 -32PT Surface Dose Rates and Occupation Exposures."

8. Transnuclear Calculation NUHO6L.0502, Revision 0, "05197/05197L Transfer Cask Shielding Evaluation for a Hypothetical Single Fuel Assembly Misload Event."

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AN AREVA COMPANY IIPage: 5of 12 2.2 List of Acronyms and Conventions DSC Dry Shielded Canister UFSAR Updated Final Safety Analysis Report TC Transfer Cask, refers to OS-I197 cask in general and its modifications unless specified otherwise TN Transnuclear Inc.

3. METHODOLOGY AND DESIGN INPUTS 3.1 Methodology The evaluation pertains to the calculation of radiation dose rates (radial) as a function of distance for the NUHOMSO 32PT DSC using design basis fuel (24 kW/DSC) loading. The shielding configuration for this evaluation is based on a drained DSC cavity with the DSCITC annulus filled with water. The decontamination shield shell (6"steel) and the shield bell are also included inthis evaluation. The configuration "F"MCNP models (reference [2]) are modified to include the defined shielding configuration. These models are then utilized to determine the radial dose rates.

The 3-D Monte Carlo particle transport computer code, MCNP5 (reference [4]), is utilized to determine the dose rates. MCNP5 is a state of the art computer code and has been utilized by TN for shielding evaluations in NRC approved applications, including the calculations documented in the UFSAR, reference [1]. MCNP5 has also been utilized in the reference

[21 calculations.

The reference design calculations [7, 1] are relied upon for the axial dose rate.

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AN AREVA COMPANY IIPage: 6of 12 3.2 Design Inputs The design basis radiation source terms (24 kW/DSC) for the NUHOMSO 32PT DSC are utilized per Reference [1,21.

The axial DSC inner cover plate welding neutron dose rate 1 meter (3 ft) from the welding shield top [1, 7, 1] is taken from page 124 of Reference [7] and Figure M.5-27 of Reference

[1]l.

The axial DSC inner cover plate welding gamma dose rate 1 meter (3ft) from the welding shield top is taken from Table 3 of Reference [8].

4. ASSUMPTIONS AND CONSERVATISMVS All assumptions and conservatisms applicable to the calculational methodology employed in the reference [2] calculations to generate the MVCNP5 models are also assumed to be valid in this calculation. Inaddition, the following assumptions and conservatisms are employed in this calculation.

1. The decontamination area shield thickness is assumed to be a nominal 6.0 inches inthe evaluation described inSection 3.1. This assumption is an input to the MVCNP5 models.

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5. CALCULATIONS 5.1 Use of MCNP5 Software A newer version of the MCNP5 computer code, version 1.4 [6], has been utilized to determine the radial dose rates. As part of the calculation/project specific verification, a single MCNP5, version 1.2 [5), computer case from reference [2] calculation is re-evaluated with this version of MON P5. The acceptance criterion for this verification is that the differences between the results of interest from the two versions of MCNP5 be within statistical uncertainty. This acceptance criterion that the two versions produce statistically similar results is adequate for the purpose of this calculation since these results are utilized to calculate the nearfield dose rates. The MCNP5 file listing for the benchmark cases is provided in Section 8.1 of this calculation. A comparison of the differences of the MCNP35 results/tallies indicates that the two versions of MCNP5 produce statistically similar results consistent with the acceptance criterion. Therefore, version 1.4 of the MCNP5 code as documented in reference [6] is acceptable for use as "limited use" software for this calculation.

5.2 MCNP5 Models For the evaluation the shielding configuration includes the 6"of shielding provided by the decontamination area sleeve and the shield bell. Inaddition, the DSC cavity is drained and the DSCITC annulus and the neutron shield are filled with water. This evaluation is performed with design basis fuel (24 kW/DSC) assemblies. The reference [2] MCNP models, Fg.mi and Fn.mi are utilized as starting models for neutron and gamma input files respectively. The MON P5 version 1.4 is used to perform these calculations.

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6. RESULTS The MCNP5 results are discussed in this section. The maximum radial dose rates I (maximum of both axial and angular) are calculated based on the discussion provided in Section 6.3.3.2 (Table 12) of reference [2]. All the MVCNP input and output files are included in the attached CD.

6.1 Axial Dose Rates for the Design Basis Fuel Loading Design basis axial dose rates for the NUHOMSO -32PT DSC loaded in the 0S197 transfer cask are calculated in Reference [7]. Reference [7] is the basis for the UFSAR [1].

Dose rates over the cask 3 ft. from the cask top are shown in Table 6-1. The neutron dose rate is calculated for a partially filled DSC/Cask annulus and a drained DSC [7], which is conservative. The peak gamma dose rate is calculated for a dry DSC under welding conditions in [1].

Table 6-1 Axial DSC Top Welding Dose Rates for 0S197L

[7] [1]Toa Location Neutron~1 (mremlhr)) Gamma (mremlhr) Totalhr (me/)

3-Feet from Welding Shield Top 14 114 128

1. Maximum dose rate 1-meter from cask top [7].

6.2 Radial Dose Rates for the Design Basis Fuel Loading The radial dose rates as a function of distance for the design basis fuel loading when inside the decontamination sleeve with water in the neutron shield and DSC/TC annulus are presented in Table 6-2. The maximum radial surface dose rate for this configuration is shown to be 67.5 mremlhour. Note that the surface dose rate is on the surface of the decontamination area shielding sleeve.

ACalculation No.: 1121-0504 TANSULA Calculation Revision No.: 1 I AN AREVA COMPANY Page: 9 of 12 Table 6-2 Maximum of Total, Gamma +Neutron, Radiation Dose Rates (Averaged over angular Coordinate) at Different Radial Distances from Side of Decon Shield Sleeve Radial Radial Distance Segment # from Side, Dose Rate, Relative meters mrem/hr Error 2 0 67.49 0.02 4 1 32.27 <0.01 6 2 19.34 <0.01 8 3 12.68 0.01 10 4.57 (15') 6.72 0.03 12 10 2.07 0.01 14 50.8 (2000") 0.08 0.02 16 100 0.01 0.02 18 200 0.001 0.04 20 300 2.76e-4 0.05 22 609.6 1.17e-5 0.15

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7.

SUMMARY

AND CONCLUSIONS Dose rates around the 0S197L on-site transfer cask containing the NUHOMSP-32PT 32 PWR fuel assemblies for normal welding conditions have been determined. This calculation is NOT a design basis or a licensing basis calculation for either the 0S197L TC or the NUHOMSO 32PT DSC.

The dose rates around the 0S197L TC when it is within the decontamination area sleeve with the shield bell and water inthe neutron shielding and the DSC / TC annulus for welding conditions are found to be:

Radial: 68 mrem/hr on surface on the decon shield sleeve.

Axial: 128 mremlhr 3 ft. from the top of the welding shield.

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8. APPENDIX A, FILE LISTING 8.1 MVCNP Runs TC shielding configuration which includes temporal (removable) 6" cask shield and water in the DSC/TC annulus is also analyzed. It is essentially TC Shielding Configuration F from reference [2] with a modified removable cask shield (increased the thickness from 5.5" to 6") and DSC/TC annulus filled with water. This evaluation is performed with design basis fuel assemblies, the reference [2] MCNP models, "Ig.miff and "Ebn.mil are utilized as starting models for neutron and gamma input files respectively. The modified models are named as "rg2.miff and "rh2.zmif.

37k Thu May 25 14:54:00 2006 Fg2.mii 712k Thu May 25 21:46:00 2006 Fg2 .mo 71k Thu May 25 21: 46: 00 2006 Fg2 -mesh 2.9k Thu May 25 21: 46: 00 2006 Fg2-tal 13M Thu May 25 21:46:00 2006 Fg2_tpe 44k Thu May 25 14:53:00 2006 Fn2.mii 630k Fri May 26 07: 47: 00 2006 Fn2 .mo 142k Fri May 26 07 :47: 00 2006 Fn2 mesh 6.9k Fri May 26 07: 47: 00 2006 Fn2_tal 33M Fri May 26 07: 47 :00 2006 Fn2_tpe The MCNP runs for OPPD specific fuel loading described in Section 5.2 were performed using MCNP 5 v.1.20 under Windows XP. The MCNP runs for the design basis fuel loading described in Section 5.2 were done using MCNP 5 v.1.40 under RedHat Enterprise Linux 4.0. To make sure that both versions give statistically the same results comparative run was done with v.1.40 under Red Hat Linux using "Ig'I" model. It is essentially the same as "i1g"input from reference [2]. To make it consistent with the reference model the same mpx as in '7g.mo" file in reference [2] was set in "ErgX.mi" file.

38k Wed Apr 26 10:45:00 2006 Fgl.mi.

721k Wed Apr 26 13:00:00 2006 Fgl.mo 71k Wed Apr 26 13:00:00 2006 Fgl mesh 3.2k Wed Apr 26 13:00:00 2006 Fgl-tal 11M Wed Apr 26 13:00:00 2006 Fgl~tpe Next files contain line-by-line comparison of output files and mesh tallies from "Erg" and "Jrgl" models. "Fqe__vs__Fgkout~puts.pzn" and "ijrqAesh__vsý__WgImesh.pzn" is a summary for output files and mesh tally results, respectively. Mesh tally 64, 84 and 144 (even R bins) represent a special interest since they were used to generate dose rates near Configuration F side in reference [2]. File comparisons were visually inspected to satisfy the acceptance criterion. It can be seen from "Erg mashý__vs__FrgA_mesh.pzn" file that dose rates for those tallies are statistically the same for both models, i.e. (dose rates)+\-(error) values lie within overlapping ranges.

903k Wed Apr 26 15:20:32 2006 Fg__vsFgl~outputs.prn 55k Wed Apr 26 15:24:51 2006 Fg~mesh-vsFgl-mesh.prn

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1121-0504 1 I AN AREVA COMPANY IIPage: 12 of12 B.2 Miscellaneous Spreadsheets All the results can be reproduced from the sets of MCNP runs listed above. However preprocessing the results is required. This section lists all the supplementary spreadsheets. The spreadsheets are not the vital part of the current calculation but can save substantial amount of time and efforts if the current calculation being used as a basis for future analysis or adjustment\estimates of results needed due to changes in source term, shielding configuration or properties, etc. The spreadsheets are in "MOIPPzocc~assdZxceI" directory of the attached CD. Note that listed spreadsheets also contain results for the mesh tallies produced during MCNP 5 runs. Mesh tallies are in "*- ass' or I* mesh" files.

The following spreadsheets contain the results for Table 6-2.

88k Fri May 26 15:07:06 2006 Configuration F2.xls 283k Fri May 26 15:29:40 2006 Configuration F2_Normal.xls 183k Fri May 26 15:29:14 2006 144_174_transposed Fg(n)2_mesh.xls