ML20046A024

Withdraws 930222 Request for Exemption from 10CFR50,App J, Type B LLRT Requirements for Containment Penetration Expansion Bellows

ML20046A024
Person / Time
Site:	Davis Besse
Issue date:	07/15/1993
From:	Storz L CENTERIOR ENERGY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
2155, NUDOCS 9307230353
Download: ML20046A024 (2)

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i. ENERGY 620000k Tree Boulevard Moil Address indepenoence OH PO Box 94661 216-447-310 0 Cleveiond. OH 441014661 Docket Number 50-346 i

License Number NPF-3 8-Serial Number 2155 July 15, 1993 United States Nuclear Regulatory Commission Document Control Desk Vashington, D. C. 20555 Subj ect : Vithdrawal of Request for Exemption from 10 CFR 50, Appendix J Type B Local Leak Rate Testing Requirements for Containment Penetration Expansion Bellows Gentlemen:

Toledo Edison's letter (Serial Number 2110) dated February 22, 1993 requested an exemption from the leakage quantification requirements specified in 10 CFR 50 Appendix J for Type B Local Leak Rate Tests (LLRTs') of containment penetration expansion bellows'at.the Davis-Besse Nuclear Power Station (DBNPS). This request resulted from Toledo Edison's review of information provided in Nuclear Regulatory Commission (NRC) Information Notice (IN) 92-20, Inadequate Local Leak Rate Testing. Information Notice 92-20 identified that potential leakage from certain types of two-ply bellow penetration assemblies may not be adequately quantifiable to satisfy 10 CFR.50, Appendix J requirements.

.As described in Toledo Edison's February 22, 1993 letter, the DBNPS containment penetration expansion bellows have two' plies. The Type B LLRT is conducted by pressurizing.the interspace between the two plies and measuring the flow rate into the interspace. Information Notice 92-20 identified that because the plies may contact one another, the flow may be restricted. This could result in a lover leakage rate being indicated by the Type B test for a leak through both bellows

! plies .han vould be indicated during an Integrated Leak Rate Test (ILRT).

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'Elght-two-ply containment penetration expansion bellows assemblies are j installed at the DBNPS.- The bellows assemblies are equipped with. test j taps to allow pressurization of the interspace between-the two bellows-plies to accommodate Type B testing. The bellows installed at the j DBNPS, unlike the bellows described in IN 92-20, incorporate a. layer of  :

stainless steel wire mesh _ covering the entire area between-the two .,

plies of the bellows. -This mesh layer is intended to improve flow distribution between the~ plies and enhance the leakage detection and measurement capability of.the Type B test method.

As stated in Toledo Edison's February 22, 1993 exemption request,.

approval of the exemption vould not be needed iffthe bellows exhibited  ;

zero measured leakage during the Type B test. Zero measured leakage

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constitutes a valid Type B test since any flow resistance between the bellows plies has no effect under zero flow conditions.

During the ei'ghth refueling outage (8RFO), conventional Type ~B tests were conducted on all eight of the two-ply containment penetration expansion bellovs assemblies. There was no leakage through any of  :

these. assemblies.- Consequently..the tests constitute valid Type B ,

tests and the requested exemption is no longer necessary. .Accordingly, Toledo Edison withdraws the exemption' request submitted by Toledo Edison's February 22, 1993 letter (Serial Number 2110).

If you have any questions regarding this matter, please contact Mr. Robert V. Schrauder at (419) 249-2366.

Very truly yours, La Louis F. Storz i

l Vice President - Nuclear PUS /dle ,

cc: J. B. Hopkins, NRC Senior Project Manager J. B. Martin, Regional Administrator, NRC Region III S. Stasek, DB-1 NRC Senior Resident Inspector Utility Radiological Safety Board

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