ML20057A763
| ML20057A763 | |
| Person / Time | |
|---|---|
| Site: | 07105450 |
| Issue date: | 09/09/1993 |
| From: | Chappell C NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Sanders C WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP. |
| References | |
| NUDOCS 9309150282 | |
| Download: ML20057A763 (5) | |
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%,.....,8 i-WASHINGTON, D.C. 20555 0001 9 0FM STSB:MGB 71-5450 Westinghouse Electric Corporation ATTN: Mr. Charles F. Sanders Orawer R Columbia, SC 29250
Dear Mr. Sanders:
As requested by your application dated September 1,1993, as supplemented September 3, 1993, and pursuant to 10 CFR Part 71, Certificate of Compliance No. 5450 for the Model Nos. RCC-1, RCC-3, and RCC-4 packages is amended to authorize the following additional contents:
Contents Type and form of material fuel assembly with a maximum Unirradiated 14x14 U0,f 7.8 inches, and consisting of square cross-section o 180 fuel rods maximum. The fuel rods are cladded in Zircaloy and have a nominal diameter of 0.4000 inches.
The active fuel length is 144 inches. The middle 132 inches of the active fuel length consists of solid pellets with a nominal diameter of 0.3444 inches. The top and bottom 6 inches of the active fuel length consist of annular pellets with a nominal inner diameter of 0.172 inches and a nominal outer diameter of 0.3444 inches. The maximum U-235 enrichment is 5.0 wt%, and the maximum U-235 loading per assembly is 18.5 kg.
Two (2) neutron absorber plates consisting of carbon steel, 0.035 inches in thickness, with 4 mils of Gd 0 are required'/cm ) affixed to each side of the plate,3 2
2 (0.02 g-Gd 0 2
between fuel assemblies. The fuel assemblies shall be held in place on the strongback with at least seven (7) clamping frame arms.
Maximum quantity of material per package Two (2) fuel assemblies 9309150282 930909
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l All other conditions of Certificate of Compliance No. 5450, Revision 30, shall remain the same.
This authorization shall expire January 31, 1994.
FOR THE U.S. NUCLEAR REGULATORY COMMISSION Original Signed by Cass R. Chappell Cass R. Chappell, Section leader Cask Certification Section Storage and Transport Systems Branch Division of Industrial and Medical Nuclear Safety, NMSS
Enclosures:
Approval Record cc w/ encl:
Mr. James K. O'Steen Department of Transportation Distribution:
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APPROVAL RECORD Model Nos. RCC-1, RCC-3, and RCC-4 Packages Certificate of Compliance No. 5450 By application dated September 1, 1993, as supplemented September 3, 1993, Westinghouse Electric Corporation requested an amendment to Certificate of Compliance No. 5450 for the RCC series packages. The application requested that the authorized coni.ents of the package be revised to include NSP 14x14 0FA fuel assemblies with annular pellets at the ends of the rods.
Specifications for the fuel assemblies are as follows:
Unirradiated 14x14 00 fuel assembly with a maximum square cross-2 section of 7.8 inches, and consisting of 180 fuel rods maximum.
The fuel rods are cladded in Zircaloj and have a nominal diameter of 0.4000 inches.
The active fuel length is 144 inches. The middle 132 inches of the active fuel length consists of solid pellets with a nominal diameter of 0.3444 inches. The top and bottom 6 inches of the active fuel length consist of annular pellets with a nominal inner diameter of 0.172 inches and a nominal outer diameter of 0.3444 inches. The maximum U-235 enrichment is 5.0 wt%, and the maximum U-235 loading per assembly is 18.5 kg.
Two (2) neutron absorber plates consisting of carbon steel, 0.035 2
inches in thickness, with 4 mils of Gd 0g 3 (0.02 g-Gd 0 /cm )
23 affixed to each side of the plate, are required between nel assemblies.
The fuel assemblies shall be held in place on the strongback with at least seven (7) clamping frame arms.
The NSP 14x14 0FA fuel assembly meets the specifications for the Zircaloy-cladded,14x14 fuel assembly previously authorized under Condition 5(b)(iii) of Certificate of Compliance No. 5450, Revision 30, except that the top and bottom six inches of the active fuel length consist of annular fuel pellets.
Two fuel assemblies will be shipped per package.
Westinghouse performed criticality calculations using the KENO-Va code to evaluate the reactivity of RCC packages loaded with NSP 14x14 Oft. fuel assemblies. The calculations were performed for an infinite array of damaged packages. Analyses of previously approved assemblies indicate that the hypothetical accident condition array represents the limiting n etivities.
Westinghouse considered five cases in their calculations. t 7 rirtion and the result of each case are summarized in Table 1 below.
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TABLE 1 - WESTINGHOUSE KENO RESULTS FOR NSP 14X14 0FA FUEL ASSEMBLY Moderator Density i
Adj. K,,,'
AK Case Model Description K,
o Config.
Inside Outside ef Rods Rods 30 model - no pkg. comp.
s lid and 1.00 0.00 0.92487 0.00490 0.94126 1
except strongback, poison
""""I*I plates, and outer shell 0.0052 3D model - no pkg. comp.
se and 1.00 1.00 0.93107 0.00425 0.94646 except strongback, poison ai_.al ar plates, and outer shell
'(isjgR.,$
2 k:9 "9 solid 0.02 0.00 0.79181 0.00401 0.80683 b
3 components i ic]uded igggy e
3D model - no pkg. comp.
solid and 0.02 1.00 0.94439 0.00375 0.95909 4
except strongback, poison annular plates, and outer shell 0.0049 30 model - no pkg. comp.
5 except strongback, poison solid 0.02 1.00 0.94007 0.00335 0.95411 plates, and outer shell 1.
Adjusted K,,, includes bias and 2a.
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3 On four of the cases (Cases 1, 2, 4, and 5), Westinghouse used a three-dimensional model that did not include any packaging components except the strongback, poison plates, and outer shell.
Cases 1 and 2 show that the array of packages is adequately subcritical when flooded with full-density water.
These cases also show that leakage of water into the internal regions of the fuel rods increases reactivity only slightly (0.0052AK increase). Cases 4 and 5evaluatedthereactivityofthearrayunderoptimymmoderation. Optimum moderation occurs with low-density water, (0.02 g/cm ) in the external regions of the fuel rods and full-density water in the internal regions of the fuel reds. These cases show that at optimum moderation, the reactivity of assemblies with both solid and annular pellets is not significantly greater than the reactivity of assemblies with only solid pellets (0.0049AK increase).
The calculated K,,f's for Cases 4 and 5 exceed the acceptance criterion of 0.95.
The model used for these cases, however, is conservative because a significant amount of steel within the packaging is ignored. Therefore, Westinghouse considered another case (Case 3) which shows that with a model that more fully represents the actual packaging design, the K,ff for an array of packages remains below 0.95 under optimum moderation.
The model used for Case 3 is a two-dimensional model that includes additional packaging components such as the clamp frames.
Case 3 yielded a K of 0.807 (including bias and 2a). Thecalculationwasperformedfo,rsolidpelletsonly and without moderation in the internal regions of the fuel rods.
Based on the small reactivity changes between Cases 1 and 2, and between Cases 4 and 5, and considering the low K,,f packages containing NSP 14x14 0FA fuel assemblies
, calculated for Case 3, Westinghouse concluded that the K for an array o err would remain below 0.95 under optimum moderating conditions.
The staff performed an independent confirmatory analysis. The staff's for an array analysisshowthatunderthemostreactiveconditions,theK,Yysisandthe of packages remains below 0.95.
Based on the applicant's ana staff's confirmatory analysis, the staff concludes that the amendment will not affect the ability of the package to meet the requirements of 10 CFR Part 71.
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L A qjx g Cass R. Chappell, Secti6n Leader Cask Certification Section Storage and Transport Systems Branch Division of Industrial and Medical Nuclear Safety, NMSS e 0IE Date: