ML18106A961

Submits Response to RAI Re Rev of AC Distribution Specification for Salem Generating Station,Units 1 & 2

ML18106A961
Person / Time
Site:	Salem
Issue date:	11/12/1998
From:	Storz L Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-91-11, LR-N980534, TAC-M98259, TAC-M98260, NUDOCS 9811240021
Download: ML18106A961 (3)

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Public Service Electric and Gas Company Louis F. Storz Public Service Electric and Gas Company P.O. Box 236, Hancocks Bridge, NJ 08038 609-339-5700 Senior Vice President - Nuclear Operations NOV 12 1998 LR-N980534 United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 Gentlemen:

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION TO LICENSE AMENDMENT APPLICATION REVISION OF AC DISTRIBUTION SPECIFICATION SALEM GENERATING STATION FACILITY OPERATING LICENSE NOS. DPR-70, DPR-75 DOCKET NOS. 50-272, AND 50-311 TAC NOS. M98259 AND M98260 On March 26, 1998, the Public Service Electric and Gas Company (PSE&G) submitted an application for amendment of Appendix A of the Facility Operating Licenses DPR-70 and DPR 75. The proposed amendment requested a change to Technical Specification 3/4.8.2.1 "AC Distribution - Operating." In this submittal PSE&G stated; " ... The proposed 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Action Time to restore the inoperable inverter to operable is supported by a PSA assessment. NRC Draft SRP Chapter 16.1, Revision 13, "Risk-

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Informed Decision-making: Technical Specifications" notes that an incremental conditional core damage probability (ICCDP) of 5.0 E-7 is considered very small. The baseline internal event core damage frequency (CDF) is based on Salem 2, however, it is representative for both Units. The baseline CDF is 9.5 E-5/year. When the D vital bus is made unavailable, the CDF increases to 1.511 E-4/year, and utilizing the NRC ICCDP, the proposed 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> allowable outage time is calculated."

On October 26, 1998, a telephone conference call took place between members of my staff and Mr. P. Milano (NRC Licensing Project Manager- Salem). During this call, PSE&G provided clarification and additional information relative to the probabilistic safety assessment information described above. The following paragraphs document the information presented by my staff.

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NOV 12 1998 Document Control Desk LR-N980534 Since the time of the original submittal, the Salem Probabilistic Safety Assessment (PSA) was updated to reflect design and procedure changes implemented during the extended outages of both Salem Units. The baseline CDFs were determined with all modeled components, including the "D" 115 Vital Instrument Bus (VIB), set at either their nominal or yearly average values. This resulted in new baseline CDF values of 4.9E-5/year and 4.6E-5/year for Salem Units 1 and 2 respectively. With the "D" 115 VIB assumed unavailable (the failure probability set equal to 1.0) the calculated CDF now becomes 6.8E-5/year for Salem Unit 1 and 6.4E-5/year for Salem Unit 2. Using

. the same ICCDP of 5.0E-7, an AOT of greater than 200 hours0.00231 days <br />0.0556 hours <br />3.306878e-4 weeks <br />7.61e-5 months <br /> can be supported.

The equation used to calculate the AOT can be also used to calculate the actual ICCDP. Using the updated model and assuming a 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> AOT for the "D" 115 VIB an ICCDP of 1.6E-7 for Salem Unit 1 and 1.5E-7 for Salem Unit 2 is obtained. Both of these values are less than the NRC ICCDP Acceptance Criteria of5.0E-7 established in Reg. Guide 1.177 "An Approach for Plant-Specific, Risk-Informed Decision Making:

Technical Specifications."

Furthermore, as stated in the supplementary response to Generic letter 91-11, dated August 14, 1992 (N92086), and re-stated in Letter dated October 28, 1997(N92155),

"A" priority work orders (Emergency Work Requiring Immediate Action) are issued when entering.an action statement 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or less. This requirement is contained in the Salem Nuclear Administrative Procedure for control of work activities. Additionally, the October 28, 1992 letter amended the August 14, 1992 letter by increasing the "D" inverter unavailability (action statement) from 24 to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, as re-stated in our March

• 26, 1998 submittal (N980038).

Should you have any questions or comments on this transmittal, please do not hesitate to contact me.

Sincerely,

/'Yy '

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Attachment 95-4933

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WO\f 12 1998 Document Control Desk LR-N980534 C Mr. H. J. Miller, Administrator - Region I U.S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Mr. P. Milano, Licensing Project Manager - Salem U. S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 14E21 Rockville, MD 20852 Mr. S. Morris USNRC Senior Resident Inspector (X24)

Mr. K. Tosch, Manager IV Bureau of Nuclear Engineering 33 Arctic Parkway CN 415 Trenton, NJ 08625