ML20249A151
| ML20249A151 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 06/08/1998 |
| From: | Gordon Peterson DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| TAC-M74394, TAC-M74395, NUDOCS 9806160110 | |
| Download: ML20249A151 (4) | |
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Duko Power Company A Duke Enng, Company Catawba Nudear Station
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4800 Concord Road York. SC 29745 Gsry R. Peterson (803) 831-4251 ornct We1%ident (803) 831-3426 fax June 8, 1998 U.S. Nuclear Regulatory Commission Attention:
Document Control Desk Washington, D.C.
20555
Subject:
Duke Energy Corporation Catawba Nuclear Station, Units 1 and 2 Docket Nos. 50-413 and 50-414 Probabilistic Risk Assessment (PRA) Studies
Reference:
- 1. Letter from M.S.
Tuckman, Duke Power Company, to Nuclear Regulatory Commission, Duke Power Company Comments on Draft NUREG-1560, dated March 3, 1997.
2.
Letter from G.R.
Peterson, Duke Energy Corporation, to Nuclear Regulatory Commission, "Probabilistic Risk Assessment (PRA), Revision 2 Summary Report, January 1998", dated February 25, 1998.
- 3. Letter from Frank J. Miraglia, Jr.,
Nuclear Regulatory Commission, to M.S. Tuckman of Duke 3
Power Company, Draft NUREG-1560: Request for i
O Comment, dated December 12, 1996.
The purpose of this letter is to inform the NRC that a voluntary initiative at the Catawba Nuclear Station to provide backup _ cooling to the high head safety injection Centrifugal Charging (NV) Pumps, as communicated in Reference 1 above and credited in the PRA analysis as communicated in Reference 2, has not yet been implemented.
Reference 3 requested Duke provide comments to the NRC on Draft NUREG-1560, " Individual Plant Examination Program:
Perspectives On Reactor Safety and Plant Performance".
By letter dated March 3, 1997, (Reference 1) Duke provided these comments.
Additionally this letter provided information for the NRC regarding the significant post-Individual Plant Examination (IPE) initiatives underway at 9906160110 990608 PDR ADOCK 0500041dL P-PDR
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U.S. Nuclear Regulatory Commission Page 2 June 8, 1998 the Duke plants that could have some relevance to the important severe accident sequences.
The March 3, 1997. Duke letter. identified that Catawba Nuclear: Station proposed a plant modification to provide backup. cooling capability to the high head safety injection Centrifugal Charging pumps.. This. modification would provide-
.the benefit of further reducing the core damage sequence frequencies for postulated accidents initiated by either the loss of the Nuclear. Service Water system or'the loss of the Component Cooling system.
In.the March 3, 1997 letter, this modification was stated to be scheduled for implementation.
in 1997.
-By letter dated February 25, 1998, (Reference 2) Duke sent the NRC a report containing the 1997 update of the PRA results for Catawba.
The results of the 1997 Catawba PRA-update are based on the beneficial effect of implementing this modification to the NV. pumps.
.The Results section
'(Section 6.) of the' report indicated that NV backup cooling is an important mitigating action for the loss of Component Cooling scenarios but.that this modification had not yet been made.
1 Duke wants to clarify to the NRC that this voluntary
' initiative to provide backup cooling to the NV pumps has not yet been completed as of June 8, 1998.
Currently, several alternative methods of implementing the modification'to the NV pumps are being considered.
Because of the conceptual design stage of the' alternatives'being considered, a I
definitive schedule for full implementation of the
. modification cannot be provided at this time.
It is Duke's
' intent to select a cost-effective option and implement it in a timely manner, consistent with the site planning and modification process.
In light.of'the delay-in the actual implementation of this modification,1the PRALcore melt frequency _results have been re-evaluated;without.the benefit of backup cooling to the NV' 2
pumps by re-calculating _certain-equipment failure rates.
- The total ~ core: melt frequency, considering the internal and external events, is re-calculated to be approximately'7.3E-5 per; reactor year without the NV~ backup cooling <as compared
.tcL4.7E-5'per' reactor' year with_the NV backup cooling as reported in-tha:1997 Catawba PRA' update'(Reference 2).
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U.S. Nuclear Regulatory Commission Page S June 8, 1938 Duke appreciates the opportunity to clarify this situation.
Should you have any questions concerning this information, please call M.S. Kitlan, Jr. at (803) 831-3205.
Very truly yo e,
a G.R.
Peter-son I
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i U.S. Nuclear Regulatory Commission Page 4 June 8, 19~98 l
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L.A. Reyes U.S. Nuclear Regulatory Commission Regional Administrator, Region II Atlanta Federal Center 61 Forsyth St.,
E W, Suite 23T85 Atlanta, GA 30303 D.J.
Roberts
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Senior Resident Inspector (CNS)
U.S. Nuclear Regulatory Commission Catawba Nuclear Station P.S. Tam NRC Senior Project Manager (CNS)
U.S. Nuclear Regulatory Commission Mail Stop O-14H25 Washington, D.C.
20555-0001 l
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