ML20091R619

Submits Response to Generic Ltr 84-09 Re Recombiner Capability Requirements of 10CFR50.44(c)(3)(ii).Requests Exemption from 10CFR50.44(c)(3)(ii) Requirements Until Completion of Proposed Mods

ML20091R619
Person / Time
Site:	Brunswick
Issue date:	06/08/1984
From:	Cutter A CAROLINA POWER & LIGHT CO.
To:	Vassallo D Office of Nuclear Reactor Regulation
References
GL-84-09, GL-84-9, NLS-84-251, NUDOCS 8406150184
Download: ML20091R619 (3)

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Cp&L 4

Carolina Power & Light Company SERIAL:

NLS-84-251 JUN 081984 Director of Nuclear Reactor Regulation Attention:

Mr. D. B. Vassallo, Chief Operating Reactors Branch No. 2 Division of Licensing i

United States Nuclear Regulatory Commission Washington, DC 20555 BRUNSWICK STEAM ELECTRIC PLANT, UNIT NOS. 1 AND 2 DOCKET NOS. 50-325 & 50-324/ LICENSE NOS. DPR-71 & DPR-62 RESPONSE TO GENERIC LETTER NO. 84-09 RECOMBINER CAPABILITY REQUIREMENTS OF 10 CFR 50.44(c)(3)(ii)

SUMMARY

This letter responds to the request for information contained in Generic Letter 84-09 dated May 8, 1984. This letter also requests that action be taken on our May 7, 1984 request (Serial No. NLS-84-194) for-an exemption from the schedule requirements of 10 CFR 50(c)(3)(ii) for Brunswick Steam Electric Plant, Unit Nos. I and 2.

With the modifications to the primary containment instrument air system discussed below, the BWR Owners' Group report

" Generation and Mitigation of Combustible Gas Mixtures in-Inerted BWR Mark I Containments" will be applicable to the Brunswick Units. Carolina Power &

Light Compan:7 (CP&L) will submit an implementation schedule within 90 days for the proposed modifications.

DISCUSSION In its March 16, 1983 letter, CP&L submitted its evaluation of the applicability of the BWR Owners' Group studies to Brunswick and concluded that with the making of one modification to the instrument air system at each Brunswick Unig, the study will be fully. applicable to. Brunswick.

With respect to the criteria provided in Generic Letter 84-09, CP&L submits the following:

1) "The plant has technical specifications (limiting conditions for operation) requiring that, when the containment is required to be inerted, the containment atmosphere be.less than four percent oxygen."

Response: Both' Brunswick Units have technical specifications (TS) j.

. requiring containment atmosphere be less than four percent oxygen when the containment is required to be inerted (refer to TS 3.6.6.3).. This-I criterion is met.

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-Mr. D. B. Vassallo :

2) "The, plant has only nitrogen or recycled containment atmosphere for use in all pneumatic control systems within containment."

r Response: Brunswick is designed with a primary containment instrument air system that uses atomspheric air as the source of pneumatic power. Any system leakage following an accident _would provide an additional source of oxygen input to primary containment that was not considered in the BWR Owners'. Group analysis and could require nitrogen dilution and possibly eventual containment venting for pressure control.

In order for the BWR Owners' Group evaluation report to envelbpe the Brunswick Units, CP&L will modify the primary containment instrument air systems to use an inert gas or recycled containment atmosphere as the pneumatic gas during post-accident conditions rather'than atmospheric air. With this modification, the BWR Owners' Group evaluation report will be fully applicable to the Brunswick U its and this criterion will be n

effectively met.

Preliminary engineering has already begun on the modification; however, CP&L will need sufficient time to complete design engineering, procure the equipment necessary for installing the containment instrument air system I

modifications, and coordinate installation with the outage' schedules of the Brunswick Units. Accordingly, within 90 days CP&L will submit a schedule for implementation of these modifications.

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3) "There are no potential sources of oxygen in containment other!than that.

resulting from radiolysis of the reactor coolant.- Consideration of potential sources of inleakage of air and oxygen into containment should include consideration of not only normal -plant operating conditions-but

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also postulated loss-of-coolant-accident conditions. These potential.

sources of inleakage should include instrument air' systems, service _ air '

systems, MSIV leakage control systems, purge lines, - penetrations pressurized with air.and inflatable door seals."

Response: ' Carolina Power & Light Company submitted an evaluation of.the BWR Owners' Group study with respect to the Brunswick Units on March-16,-

1983 that concluded that the~ primary containment instrument air system was:

.the 'onlyferedible post-LOCA source of oxygen not considered'in the Owners' Group study. The proposed modification to.the'primaryfcontainment instrument air system discussed in the response to criterion' number 2 t

above will effectively meet this ' criterion.

. During the interim period until the instrument air _ system' modifications can. be' Jaade,-the-Brunswick Units'will'useithe existing containment-atmosphere' control systems lin conjunction with _ the standby gas treatment systems.to avoid.

unacceptable concentrations of_ combustible gas in'the unlikely. event of a loss-of-coolant accident. TheLcontainment atmosphere dilution'(CAD)! system.

will'be used to' control the: oxygen concentration after an accident by adding; nitrogen.:.In_the unlikely eventzof'high'containmentfpressure, the pressure-may be relieved by ~ venting through the. standby -gas ' treatment system. The.

combur tible gas controls described -above are addressed in the Brunswick FSAR.

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'Mr. D. B. VcIsslE) "

CONCLUSION When the proposed modifications are complete, the Brunswick Units will meet

.the assumptions of the BWR Owners' Group generic study and the intent of Generic Letter 84-09 criteria. The Brunswick Units will not rely upon purge /repressurization systems as the primary means of hydrogen control and, therefore, will not require the installation of hydrogen recombiners.

In the interim period, an exemption from the schedule requirements of 10 CFR 50.44(c)(3)(ii) will be required. Therefore, as requested in our "05000324/LER-1984-005, :on 840228,Tech Spec 3.6.3a,re Inoperability of Primary Containment Isolation Valves,Not Met When Valve Packing on [[system" contains a listed "[" character as part of the property label and has therefore been classified as invalid. Sys Inlet Outboard Isolation Valve 2-G31-F004 Adjusted|letter dated May 7,1984]], CP&L requests that an exemption be granted until completion of

-the modifications described above. This exemption is needed prior to expiration of our existing exemption on June 30, 1984.

Should you have any further questions on this issue, please contact Mr. S. R.

Zimmerman at (919) 836-6242.

Yours very u[

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/W hg A. B. Cutter - Vice President Nuclear Engineering & Licensing JSD/cce (205JSD) cc:

Mr. D. O. Myers (NRC-BSEP)

Mr. J. P. O'Reilly (NRC-RII)

Mr. M. Grotenhuis (NRC) r n

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