ML20057D147

Forwards Response to NRC Bulletin 91-001,Suppl 1, Reporting Loss of Criticality Safety Controls. Westinghouse Will Upgrade Site Emergency Plan to Incorporate Addl Language from Suppl for Addl Clarification & Training Purposes

ML20057D147
Person / Time
Site:	Westinghouse
Issue date:	09/24/1993
From:	Fici J WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
CON-NRC-93-026, CON-NRC-93-26 IEB-91-001, IEB-91-1, NUDOCS 9310010179
Download: ML20057D147 (2)

Text

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s Westinghouse Commercial Nuclear Drawer R Electric Corporation Fuel Division

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September 24,1993 NRC-93-026 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk washington, DC 20555 Gentlemen:

Reference:

NRC Bulletin 91-01, Supplement 1: " Reporting Loss of Criticality Safety Controls" Westinghouse Electric Corporation (Westinghouse) has reviewed NRC Bulletin 91-01 Supplement 1 and the accompanying attachment, dated July 27,1993, and has concluded that its current notification criteria and management implementation procedures either meet or exceed the minimum criteria specified in the subject Bulletin Supplement. Westinghouse will, however, upgrade its Site Emergency Plan to incorporate additional language from the Supplement, for additional clarification and training purposes. This effort will be included in the next revision of the Site Emergency Plan, scheduled for completion by December 31, 1993. In addition, Westinghouse has identified three issues, arising from the supplement, that beg additional discussion. Details of these issues are included in Attachment I to this letter.

I hereby affirm that the statements and commitments in this response are true and correct to the best of my knowledge and belief.

Should you have any questions, or need additional information, please telephone me at (803) 776-2610, Ext. 3300.

Sincerely, WESTINGHOUSE ELECTRIC CORPORATION 0.

(. A. Fici, Plant Manager Columbia Fuel Fabrication Facility cc:

U. S. Nuclear Regulatory Commission-Region 11 Regional Administrator 101 Marietta Street, NW Atlanta, GA 30323 11:\\

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WESTINGHOUSE RESPONSE TO NRC BULLETIN 91-01, SUPPLEMENT 1 ATTACHMENT I l

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The Westinghouse Electric Corporation (Westinghouse) takes this opportunity to open discussion on three issues arising from Supplement I to Bulletin 91-01:

" REPORTING LOSS OF CRITICALITY SAFETY CONTROLS."

The first issue relates to the Supplement's definition of " safe mass." Westinghouse does not f

believe that 45 percent of the minimum critical reflected mass is an appropriate limit for notification criteria that claims the Double Contingency Principle as its basis. The operative i

phrase in the Principle requires at least two independent, concurrent, unlikely events "before criticality is nossible". This would seem to imply that the minimum critical reDected mass,"

l with its built-in conservatisms of optimum moderation and full reflection, would be a more I

appropriate criterion for notification of mainr nuclear criticality events involving substantial degradation of controls. Then, as is existing practice, 45-percent of the minimum critical i

reflected mass would continue to be the margin of safety applied for administrative control of I

low enriched uranium mass; and, 75-percent of the minimum critical reflected mass would continue to be applied for engineered control of low enriched uranium mass. This appears to be a more consistent approach, and Westinghouse proposes it for consideration, j

The second issue relates to lack of a Supplement definition of " volume of water-equivalent of j

concern" that might be inadvertently introduced to low enriched uranium under' primary i

moderation control. Westinghouse proposes 19-liters as this " volume of concern."

The third issue relates to the Supplement's silence on those cases where overmoderation (i.e.,

i concentration) is used as the primary criticality control. In such cases, the minimum critical reflected mass and the 19-liters of water equivalent often constitute normal operation. Here, Westinghouse prop -

that "24-hour notification criteria" be invoked if uranium concentration j

increases beyond 10 ns of U-235 per liter, but prompt remedial action is taken"; and, that j

s "immediate notification criteria" be invoked if uranium concentration increases beyond 10 grams of U-235 per liter, and prompt remedial action cannot be taken."

i Westinghouse invites additional discussion regarding these very important issues, and appreciates this opportunity to participate in development of the regulatory processes.

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