ML20058F923
| ML20058F923 | |
| Person / Time | |
|---|---|
| Site: | Westinghouse |
| Issue date: | 11/07/1990 |
| From: | Wilson R NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Bidinger G NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| References | |
| NUDOCS 9011090220 | |
| Download: ML20058F923 (4) | |
Text
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UNITED STATES
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NOV 7 1990 f
MEMORANDUM FOR:
George H. Bidinger, Section Leader Uranium Fuel Section fuel Cycle Safety Branch Division of Industrial and Medical Nuclear Safety, NMSS FROM:
Robert E. Wilson Uranium Fuel.Section Fuel Cycle Safety Branch Division of Industrial and Medical Nuclear Safety, NMSS
SUBJECT:
> PROGRESS REPORT ON WESTINGHOUSE AMENDMENT O
I have completed an initial review of an amendment _ application from the JWestinghouse Electric Company dated iluly 2,1990, requesting a change to the g-h existing K limit for one operating station at the Columbia Fuel Fabrication Facility. eIbe proposed change is for the K limit for the wash station to be eff increased from 0.95 to 0.98.
The safety issue is that the proposed limit would-allow for essentially no room
~for conditions that could increase the K Attachments 2 and 3 of the request addressedanumberof-abnormal. condition $kn,ddiscussedcontingenciesforthem.
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- Three =of-the failures listed in attachment 2 deal with operational problems.
Two ofothese failures. deal =with double-batching assemblies in=a wash pit. The third. failure was mechanical damage increasing reactivity.
The discussion
. maintained th'at all damage would decrease K of the assembly.
I performed i
calculationswithaKEN05amodelofaWestikbouse17:by170FAfuelelement.
These calculations focused on 1) ~:serators more effective than water,.
l 2). increased rod. spacing in t6 element due to mechanical-damage, 3) the effect '
- of a. steel box in the pit to surround the fuel, and 4) the effect of a' concrete reflector. The'results are shown'on the enclosed table.. From these calculations i concluded that'1) moderators with a CH or CH, base need to be excluded from the area, 2) the-concrete pit walls must be cohsidered, and 3) mechanical damage 3
to the. fuel must be. precluded. The last category would deal'with dropping.the
' fuel-into.the' pit. floor or. dropping something. heavy on'the-fuel.
The test weight-for.the crane is an example of an.obiect'that could be dropped. To-deal with this concern, Westinghouse could supply tests or analysis to show that the fuel would.not deform under credible accidents or describe rigorous controls on the operation to preclude:the accidents.
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NOV 7 1990
, George H. Bidinger 2
-It is noted that a. simple physical fix is available.
A stainless steel enclosure for the fuel assembly would lower K and thus eliminate the need for the amendment. A borated steel box would be $vbn more effective and provide for a larger volume for the fuel assembly,
-1 hAve drafted a letter to Westinghouse asking for more information.
I h
Robert E. Wilson Uranium Fuel Section Fuel Cycle Safety Branch.
Division of Industrial and Medical Nuclear Safety, NMSS 1
Enclosure:
. As stated I
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NOV 7 1940 2-it is noted that a simple physical fix is available. A stainless steel enclosure for. the fuel assembly would lower K and thus eliminate the need for the amendment. Aboratedsteelboxwouldbe$Nnmoreeffectiveandprovidefor
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-a larger volume for the fuel assembly.
-1..have drafted a letter.to Westinghouse asking for more information.
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w Robert E. Wilson
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Vranium Fuel Section Fuel Cycle Safety Branch Division of Industrial and Medical Nuclear Safety, NMSS h
Enclosure:
As stated Distribution'w/ encl.
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Westinghouse 17x17 OFA Fuel Assembly
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Moderator. Reflector Bou Gap-1-eff Chance Comments i
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,H20
,H2O 0.941 Base Case
-CH -
CH 0.963 0.002 i
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CH2
.1.017
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H20-H2O 1.010 0.067 fiod spacina. increased 117.
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Concrete 0.960 0.019 Concrete on 3 sides 0.931 0.010 Concrete on i sido i
i H20' 1/2" O.902
-0.039 1/4" 304SS box 1/2" O.848
-0.093 1/4" 17. baron 7045S box f
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O.'873
-0.068 l
1".
O.894
-0.047 1 1/4" O.907
-0.034
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