ML20082K340
| ML20082K340 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 04/13/1995 |
| From: | Meisner M ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20082K344 | List: |
| References | |
| GNRO-95-000054, GNRO-95-54, NUDOCS 9504190244 | |
| Download: ML20082K340 (3) | |
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Ent:r y Cp;rcti:ns,Inc.
= ENTERGY eo so 7 6 Port Gbson. MS 39150 Tel 601437 6470 M. J. Meisner twwr April 13, 1995
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U.S. Nuclear Regulatory Commission Mail Station P1-37 Washington, D.C. 20555 Attention:
Document Control Desk
Subject:
Grand Gulf Nuclear Station Docket No. 50-416 License No. NPF-29 Modification of the Technical Specifications Operability and Surveillance Requirements for the Main Steam isolation Valve Leakage Control System Proposed Amendment to the Operating License (PCOL-93/05 revision 1)
Reference:
1.
GNRO-93/00069, Modification of the Technical Specifications Operability and Surveillance Requirements for the Main Steam isolation Valve Leakage Control System Proposed Amendment to the Operating Ucense (PCOL-93/05), dated June 23,1993.
2.
Issuance of Amendment No.120 to Facility Operating License No. NPF Grand Gulf Nuclear Station, Unit 1 (TAC No.
M88101), dated February 21,1995.
GNRO-95/00054 Gentlemen:
During a meeting with members of the Staff on April 6,1995, additionalinformation was requested concerning the calculations and testing performed by Entergy Operations, Inc. at Grand Gulf Nuclear Station (GGNS) to support a design change for the Main Steam isolation Valve (MSIV) Leakage Control System (LCS). Attachment 1 provides the requested information.
Also, Entergy Operations, Inc. requests that the proposed scope of the requested Technical Specifications change be reduced to leave in the Technical Specifications the requirement to test the outboard MSIV LCS blowers. Attachment 2 provides for your use modified Technical Specifications pages and associated Bases pages reflecting this scope reduction.
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April. 13, 1995 GNRO-95/00054 Page 2 of 2 The attached information and the reduced scope is boun' fed by the previous basis l
provided in Reference 1 for the Entergy Operations, Inc determination that the l
proposed amendment involves no significant hazards considerations based on the
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guidelines presented in 10CFR50.92.
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l We appreciate the Staff's efforts to review t.e requested Technical Specification k
change and the constructive dialogue concerning the changs at the April 6 meeting.
Yours truly, i
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MJM/BSF attachments: 1.
Additional Information (1 page) 2.
Revised Technical Specification and Bases pages (3 pages) cc:
Mr. H. W. Keiser l
Mr. R. B. McGehee l
Mr. N. S. Reynolds Mr. J. E. Tedrow Mr. H. L. Thomas Mr. Stewart D. Ebneter (w/a)
Regional Administrator U.S. Nuclear Regulatory Commission Region 11 101 Marietta St., N.W., Suite 2000 Atlanta, Georgia 30323 Dr. Alton B. Cobb (w/a)
State Health Officer State Board of Health P.O. Box 1700 Jackson, Mississippi 39205 Mr. P. W. O'Connor, Project Manager (w/a/2)
Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission l
Mail Stop 13H3 l
Washington, D.C. 20555 l
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GNRO 95/00054 Page 1 of 1 Additional Information The design alternative being pursued by Grand Gulf Nuclear Station (GGNS) for the Main Steam Isolation Valve (MSIV) Leskage Control System (LCS) is the removal of some active functions of the inboard system and leaving the outboard system intact. The modified MSIV-LCS system will consist of the inboard depressurization line with the inboard blowers, heaters, and flow elenients de-energized.
Additionally, setpoints are modified as needed to support the revised system design.
GGNS has performed calculations that demonstrate that with the Standby Gas Treatment System (SGTS) operating the inboard MMV-LCS can achieve and maintain a sub-atmospheric condition in the Main 3 team Line (MSL) without the use of blowers. These calculations assume a flow rate of 50 scfh (25 scfh leak rate for the inboard MSIV and 25 scfh for the outboard MSIV) into the space between the i
MSIVs and a vacuum of -0.25 inches water in the Auxiliary Building. The -0.25 l
inches water is the SGTS drawdown design pressure.
In addition, during the last refueling cutage GGNS performed testing which depressurized the steam line piping under beyond-design-basis conditions using the modified inboard system flowpath and demonstrated SGTS's ability to direct MSIV leakage without the inboard blowers. The testing conservatively used helium gas l
injected via test connections into the main steam lines to simulate airborne fission l
products. This testing was performed with all MSIVs and safety related outboard main steam supply shutoff valves open (simulating multiple failures and maximizing the operational challenge to the SGTS for conservatism) and the design flowpaths were confirmed using sensitive helium detectors. This testing also demonstrated that the modified system flowpath would not adversely affect the OPERABILITY of the SGTS.
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