ML18078A820

Responds to NRC 781128 Ltr Re Containment Purging During Normal Plant Operation.Contends That Design of Purge & Pressure Relief Valves Are in Full Compliance & Design Is Not Subject to Override Conditions to Prevent Valve Closing

ML18078A820
Person / Time
Site:	Salem
Issue date:	01/30/1979
From:	Librizzi F Public Service Enterprise Group
To:	Schwencer A Office of Nuclear Reactor Regulation
References
NUDOCS 7902060268
Download: ML18078A820 (2)

Text

, e Public Service Electric and Gas Company 80 Park Place Newark. N.J. 07101 Phone 201/430-7000 January 30, 1979 Director of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Attention:

Mr. Albert Schwencer, Chief Operating Reactors Branch #1 Division of Operating Reactors Gentlemen:

CONTAINMENT PURGING DURING NORMAL PLANT OPERATION SALEM GENERATING STATION UNIT NO. 1 DOCKET NO. 50-272 In response to your letter of November 28, 1978, concerning Containment Purging During Normal Plant Operation, we offer the following response as justification for unlimited purging: 1. Branch Technical Position CSB 6-4 and the Standard Review Plan, Section 6.2.4 permit purging of the containment during normal plant operation if the valves are capable of closing against the dynamic forces of a design basis LOCA, and if the impact of purging during operation on ECCS performance is evaluated, and if an evaluation of radiological consequences during such events is performed.

All of these analyses have been performed on either the Unit 1 or 2 dockets and are applicable to both units. (See responses to NRC questions 5.66 and 14.13). The Unit 2 SER requires resolution of only the valve closure capa-bility question.

• • • • • We have. transmitted information to the NRC (Mr. G. Zeck) which describes the physical characteristics of butterfly valves under flow conditions and shows that valves of this type always tend to close when subjected to the forces of the flowing fluid. Since it was not possible to simulate the containment conditions seen by the Salem isolation valves during a LOCA, other tests were performed to demonstrate the valves' ability to meet age and seismic requirements.

These tests, in conjunction with the previously referenced technical data on butterfly valves, provide assurance of valve operability during design basis event tions. \O I' 95-2001 1200Ml 2* 78

---....... * * .1 ** / Dir. NRR 1-30-79 2. There is no basis for having to assume that the valves must operate against the maximum containment pressure during a LOCA since the valves are signaled to close early in the event and will be fully closed prior to reaching a containment pressure of 20 psig. 3. The valves have been successfully tested for leak tightness when closed against the maximum LOCA pressure.

4. It has been our experience, especially during the warmer months or changing ambient barometric pressure, that relief is required to maintain the containment pressure in Technical Specification limits. During cooler weather ditions, the need for pressure-relief is less frequent but, on a yearly basis, we would require more than the proposed able 90 hours0.00104 days <br />0.025 hours <br />1.488095e-4 weeks <br />3.4245e-5 months <br /> of operation on this system. 5. The design and operating conditions described above are identical for both Salem units. 6. It is our contention that the design of the Salem purge and pressure relief valves is in full compliance with the ments of the applicable Branch Technical Positions and that no restrictions should be placed on the operation of any valves. 7. We have performed an evaluation of the instrumentation and controls circuits as requested in the November 28, 1978 letter from the NRC.

• This evaluation has confirmed that our design is no longer subject to override conditions which could prevent automatic valve closure during a LOCA. The documentation of this evaluation is available at the Salem Station. If you have any other questions concerning this subject, please do not hesitate to contact us. Very truly yours, , I F. P. Libriz:d_

General Manager -Electric Production