ML20034C584
| ML20034C584 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 05/01/1990 |
| From: | Wallace E TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-88-20, NUDOCS 9005040167 | |
| Download: ML20034C584 (3) | |
Text
{{#Wiki_filter:T 3 - j.. g TENNESSEE VALLEY AUTHORITY CH ATTANOOGA. TENNESSEE 37401 5N 1578 Lookout Place MAY 011990 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk t Washington, D.C.' 20555 -Gentlemen: i In the Matter of ) Docket Nos.'50-259 , fere,essee Valley Auth4rity ) 50-260 50-296 t BROHNS FERRY NUCLEAR PLANT (BfN) - PROBABILISTIC RISK ASSESSMENT (PRA) AND EMERGENCY OPERATING PROCEDURE (EOP) 1 This submittal is to document !!.0, resolution of the staff's PRA and E0P concern as documented by letter fm NRC'to'TVA dated July 10, 1989, and included in Supplement I to the Safety Evaluation Report (SER) on;the Browns Ferry Nuclear Performance Plan (NPP) - Q! REG-R3?,,which was sent by letter from NRC to TVA dated October 24, 1989. j A -teleconference was held on April 11,199Q to slarJ fy the-staf f's. concern. In that teleconference, the staff stated that jf had two concerns' regarding the adequacy of.the PRA sequence'which-pertains to the residual" heat removal (RHR) system (PRA Sequence 4). This PRA' sequence invp'ives i, transient which is followed by 1 to 3 stuck open relief valves. The ARC rsoncerns;and TVA responses are provided below: f NRC Concern: TVA'ncy.hrte overestimated the proba'bility of an opcrator failing to take proper ccrrective actions, 'The'sta?f suggested- / BFN review the e/ plicable E0Ps and reeva. of operator ' errors to determine a more r,luate the probability' salisticifitimate of operator failures. ' I TVA Response: TVAwillrevisethehumanfactors. consider (tions,which,[ ~ / includes an esti.mation of-the p'robability of operatu errors; for the next PR/r ubdate, TVA is committed to provi G 9 sunmary-report of the updated PRA by September 1.,1992. TVA tiple this j commitment in response to Generi!.: Letter 4]L) 88-20, Individual Plant Examinattort for Severe Accident Vu%rabilities, by letterfromTVAJoNRC,datedOctober 30, 1989. NRC requested, in GL 88-20 and by letter from NRC to TVA dated January D,
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1990, that TVA /ubmlt this report so6ner if the updated PRA,is completed prior to this commitment date. It is TVA's intedt,to / support this request
- NRC Concern:
The staff would Bike to see venting, using the hardened vent $/ I s discussed by Generic Letter 89-16, incorporated into the PRA f for this sequenc6. h7Q ADOCV0500ff{'9 JPjdsl.'8/4 /84#M8 l 9005040167 900501 ' /' ,p ggsfS2,Wjd i' y / DR 3 ' fj' An Equal Opportunity Employer I R{#1 ,( '.c
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s .. ~ ( ~ 0, s '3 \\ ' 'h8; ) ) 4 3 m ' 1 a 6 U.S.NuclearR?dt athyCommission b i s a 4 e m TVA Response: As requested by GL 88-20, TVA's intentions are far the BFN PRA ~ n 1,
- o be a living document which reflects.the current design of FN. When BFN installs the hardened v60t, the BFN PRA will be updated to reflect this change in plant design.
If this 5 modification,ls incorporated prior to completion of the next update of the PRA, it will be incorporated in the update. If G the h g dened vent is installed after the current update of the T VN Pk;.',b tho hardened vent will. be incorporated into the next update of the Bru PRA. It is TVA's intent to* install the 4 ' hardened vent on Unit 2 during the first scheduled refueling. (' octage after restart. This commitent was provided'in responsn 2 1 to GL Bf'-16, installation of Hardened Wetvall Vent by TVA i' [ ] letter to NR:. dated October 30, 1.989, ,/ A summary list of commitments contained in this letter is provided in the enclosure. If you have any questions, pleasptelephone Patrick P. Carter, Manager of Site Licensing, at (205) 729-3570. / s Very truly yours, + ( TENNESSEE VALLEY AUTHORITY , Ni [ 3 e G. Wallace, Manager Nuclear Licensing and s q Regulatory. Affairs Enclosure cc (Inclosures): T i Ms. S. C. Black, Assi, tant Director forProjects TVA Projects Division U.S. Nuclear Regulatory Crx41ssion One, White fitrA ' North 11555 Rockville Pike ~ Rod.ville, Maryl6nd 20852 Mr. B. A. Wil' hon, Assistant' Director for Inspection Programs TVA Projects Division s U.S. Nucicar Regulatory (p ulsMor, i Region IT 101 Martetta Street, NW, Suitt 2900 i Atlanta, Georgia 7 70323 s, ~ NRC Reside t Inspector Browns Ferg Nuclear Plant Route 12, Fox 637 Athens, Alabama 35609-2000 J g i ) 4 j s 3, c j
f53 3 ^ y, .;., e:ij 5. n. ( ENCLOSURE /' a
SUMMARY
OF COMMITMENTS i s i O
- 1.g TVA' wlli revise the. human factors considerations..which includes an
{ ~$ estimation of~the probability of. operator trrors, for the next i y Probabillstic, Risk Assessment!(PRA) update. '2. Yhe.t 8rowns Ferry Nuclear Plant (BFN) installs the hardened vent, the BFN i ( ?. .PRAwillbe-updatedtoreflectthis.changeinplantdesign.Olf-this.. y modification is Incorporated prior to completion of the next update of J the PRA; it vill be incorporated in the. Update., If-the' hardened vent is = installed after the' current update of the BFN PRA the hardened vent will i 9j. be incorporated into the next update of,the BFN PRA. -l l il .h j -i i f o 6 L v l r I l Q{~ Q j c s i i k
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