ML20149M400
| ML20149M400 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 02/18/1988 |
| From: | Shelton D TOLEDO EDISON CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| 1480, NUDOCS 8802260021 | |
| Download: ML20149M400 (2) | |
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TOLEDO
%es EDISON A Cerwxr Dergy Ccrrpery DONALD C. SHELTON Docket No. 50-346 vunne-oau*-
(419]249 2300 License No. NPF-3 Serial No. 1480 February 18, 1988 United States Nuclear Regulatory Commission Document Control Desk Washington, D. C.
20555
Subject:
Testing of Reactor Vessel Internals Vent Valves Gentlemen:
The purpose of this letter is to request a clarification of the NRC Staff's position regarding the scheduled testing of the Reactor Vessel Internals Vent Valves (RVVVs) at the Davis-Besse Nuclear Power Station, Unit No. 1.
Surveillance Requirement 4.4.10.lb of the Davis-Bessc Technical Specifications requires that each RVVV be demonstrated operable at least once per 18 months during shutdown.
Due to an extended shutdown period commencing in June 1985, Toledo Edison requested a one-time extension of the surveillance interval (Serial Nos. 1278 and 1292).
License Amendment No. 95 provided this extension by adding the following footnote to the Surveillance Requirement:
For Cycle 5 operation, performance of this Surveillance Requirement may be deferred to coincide with the next reactor vessel head removal but no later than the Cycle 5 refueling outage.
Although the license, as amended, provided no specific date, the NRC Staff cover letter dated August 20, 1986 (Log No. 2055) which transmitted License Amendment No. 95 to Toledo Edison stated:
i This amendment modifies Surveillance Requirement 4.4.10.lb to permit a one-time extension of the surveillance interval for the reactor vessel internals vent valves from if anths (plus an allowable extension of 25 percent) to until the reactor vessel head is removed or until the refueling following Cycle 5 operation. Although no specific date is included in the fechnical Specifications by when the surveillance must be done, it is understood that testing of these valves will be done approximately no later than March 1988.
Thus the surveillance interval will have been extended to approximately 42 months maximum.
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THE TOLEDO EDLSON COMPANY EDtSON PLAZA 300 MADISON AVENUE TOLEDO. OHIO 43652 8802260021 880218 PDR ADOCK 05000346 P
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r Ifock'et No. 50-346 License No. NPF Serial No. 1480 Page 2 The reactor head has not been removed since License Amendment No. 95 was issued by the NRC Staff. The RVVVs were last tested on October 12, 1984 during shutdown for refueling in preparation for Cycle 5.
At the time Toledo Edison requested and received the extension in August, 1986, the fifth refueling outage was expected to commence in the December 1987 to early January 1988 timeframe (based on remaining fuel life and a November 1986 restart date). Accordingly, it was believed that a three-month refueling outage wor.1d end by March 31, 1988. However, based on an actual restart date of December 22, 1986 and remaining fuel life, the fifth refueling outage is now scheduled to cornence on March -11,1988, and to last approximately six months.
The Basis for Technical Specification 3/4.4.10 discusses that the RVVVs are provided to relieve the pressure generated by steaming in the core following a Loss of Coolant Accident (LOCA) so that the core remains sufficiently covered, i.e.,
to prevent-voiding in the core. USAR Subsection 4.2.2.2.8 discusses that the RVVVs are installed in the core support shield to prevent a pressure unbalance which might interfere with core cooling following a postulated inlet pipe rupture (such as a break in the reactor coolant system cold leg or double-ended break of a core flood line). The RVVVs promote expulsion of steam produced in the core directly to the break, thus enhancing the effectiveness of the Emergency Core Cooling System injection. When the reactor is in a refueling mode with the reactor head removed the above concerns are not a consideration.
Accordingly, Toledo Edison believes that with the shutdown of the plant in March 1988 for the fifth refueling outage, the intent of the NRC Staff's position will be met.
The testing of the RVVVs anytime prior to completion of the Cycle 5 refueling outage will also neet the NRC Staff's position and is in strict compliance with' Technical Specification Surveillance Requirement 4.4.10.lb.
The NRC Staff's review of this clarification and any comments or non-currence with it is requested by March 11, 1988.
Very tr y yours, DRW: ban ec: DB-1 Resident Inspector A. W. DeAgazio, NRC/NRR Davis-Besse Project Manager 1
A. B. Davis, Regional Administrator l
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