ML20137L687
| ML20137L687 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 09/06/1985 |
| From: | Charemagne Grimes Office of Nuclear Reactor Regulation |
| To: | Thadani A, Thasani A Office of Nuclear Reactor Regulation |
| References | |
| TASK-05-11.A, TASK-06-07.C1, TASK-08-03.B, TASK-5-11.A, TASK-6-7.C1, TASK-8-3.B, TASK-RR NUDOCS 8509120450 | |
| Download: ML20137L687 (3) | |
Text
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NUCLEAR REGULATORY COMMISSION 2
WASHING TON, D. C. 20555 Septen.ber 6,1985 Docket No.: 50-245 MEMORANDUM FOR:
Ashok Thadani, Chief Reliability and Risk Assessment Branch, DST FROM:
Christopher I. Grimes, Chief Systematic Evaluation Program Branch, DL
SUBJECT:
STATUS OF MILLSTONE 1 SEP ISSUES In T. Speis's memorandum to H. Thompson, dated August 20, 1985, forwarding comments on the FTOL SER for Millstone 1, questions regarding the status of three SEP issues were raised:
(1) an additional instrument AC bus; (2) reduction of allowable outage limits on station emergency batteries; and (3) the installation of an RWCU pressure interlock.
In the evaluation of SEP Topic VI-7.C.1, presented in the Millstone 1 IPSAR (NUREG-0824), it was stated that a failure of the single instrument AC bus may result in the loss of essential instrumentation or controls needed to reach safe shutdown. The licensee committed to evaluate the existing automatic bus transfers. Following the issuance of the IPSAR, TAC #49384 was issued to track the progress of the licensee's evaluation. In response to the licensee's 1983 request to participate in ISAP, we included this 1ssue in the scope of the ISAP issues for Millstone 1 (refer to ISAP Issuc
- 1.21 in the staff's July 31, 1985 letter). During the Fall 1985 outage, the licensee is planning to replace instrument transformers.
In addition, the licensee is performing an evaluation of breaker coordination (ISAP Issue
- 2.17) which will directly impact the findings for this issue. Also, Northeast Utilities (NU) will submit its probabilistic analysis of this issue for the staff's review by leptember 6,1985. The final disposition of this issue will be detennined in the ISAP integrated assessment.
In the evaluation of SEP Topic VIII-3.B. presented in the Millstone 1 IPSAR, it was found desirable to reduce the existing seven day battery outage limit to the two hour STS limit based on the PRA insights from IREP. The licensee comitted at that time to evaluate the outage limits and either change the Millstone 1 TS or justify the existing limits. The licensee has completed its evaluation of the limits and has found that the outage limits in the STS are overly restrictive and may cause system operational problems because of the nature of the design and surveillance procedures for the Hillstone 1 batteries.
The licensee is currently developing a proposed TS change which would allow a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> outage limit for the emergency batteries. When this TS change is submitted to the NRC, the ORPM will coordinate its review. The completion of this issue is outside of the ISAP scope of issues.
CONTACT:
M. Boyle X-28935 8509120450 850906 PDR ADOCK 05000245 P
Mr. John F. Opeka Millstone Nuclear Power Station Northeast Nuclear Energy Company Unit No. I cc:
Gerald Carfield, Esquire Kevin McCarthy, Director Day, Berry & Howard Radiation Control Unit Counselors at Law Department of Environmental City Place Protection Hartford, Cor.necticut 06103-3499 State Office Buildir.g Hartford, Connecticut 06106 Edward J. Mroczka Vice President, Nuclear Operations Northeast Utilities Service Company Post Office Box 270 Hartford, Connecticut 06141-0270 i
State of Connecticut Office of Policy and Management ATTN: Under Secretary Energy Division 80 Washington Street Hartford, Connecticut 06106 Regicnal Administrator, Region I U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prus:ta, Pennsylvania 19406 Northeast Nuclear Energy Company ATTN: Superintendent Millstone Nuclear Power Station P. O. Box 128 Waterford, Connecticut 06385 Resident Inspector c/o U.S. NRC Millstone Nuclear Power Station P. O. Box 811 Niantic, Connecticut 06357 First Selectman of the Town of Waterford Hall of Records 200 Boston Post Road Waterford, Connecticut 06385 L
September 6 1985 0
. With respect to the RWCU interlock, there were two methods in SEP for the resolution of Topic V-11. A.
The first mathod was the installation of an independent pressure interlock and the second method was an evaluation of the adequacy of existing relief capacity to prevent overpressurization and to evaluate the upgraded emergency proced'. res for diagnosing and terminating this event. The licensee, in the Millstone 1 IPSAR, comitted to install the pressure interlock for the inboard suction valve on the RWCU by Spring 1984.
However, in September and December 1983 letters, NU proposed to include the RWCU pressure interlock issue in ISAP. At that time NU had completed the engineering and purchased the materials necessary to install the interlock. Because of the small gain in safety based upon their risk analysis and related operational and maintenance considerations, the licensee requested that the second method of resolving this issue be evaluated in ISAP. On April 5,1984 the staff sent a letter to NU granting schedular deferrals for several projects, including the RWCU pressure interlock issue, pending the completion of ISAP. The staff's July 31, 1985 letter to NU, formally detailing the scope of the Millstone 1 ISAP review included this issue (#1.04). At present, the August 13 and 23, 1985 submittals by NU on this topic are under review. The final disposition of this issue will be determined in the ISAP integrated assessment.
Original signed by:
M. Boyle for C. I. Grimes Christopher I. Grimes, Chief Systematic Evaluation Program Branch, DL cc:
H. Thompson T. Speis DISTRIBUTION J. Zwolinski Doctet m e 7 J. Shea SEPB Reading E. McKenna CGrimes M. Rubin Millstone Service List M8oyle DCrutchfield NRC PDR L PDR HThompson OELD E. Jordan B. Grimes J. Partlow ACRS (10)
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