ML19093A972
| ML19093A972 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 09/12/1977 |
| From: | Stallings C Virginia Electric & Power Co (VEPCO) |
| To: | Case E Office of Nuclear Reactor Regulation |
| References | |
| Download: ML19093A972 (2) | |
Text
e VIRGINIA ELECTRIC.A.ND POWER COMP.A.
RIOHMOND,VIRGINIA 23261 September 12, 1977*
Mr. Edson G. Case, Acting Director Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D.C.
20555 Attention:
Mr. Robert W. Reid, Chief Operating Reactors Branch 4
Dear Mr. Case:
Serial No. 382/082477 PO&M/ALH:das Docket Nos. 50-280 50-281 License Nos. DPR-32 DPR-37 The information and analyses requested in your order of August 24, 1977 are provided in the attachment to this letter.
As a result of the analyses performed since our August 24, 1977 meeting with your staff, we have determined that the operating restrictions in the August 24, 1977 order may be relaxed to permit a wider range of service water temperatures.
We have found that an increased RWST water level results in several benefits to the LOCA transient.
The increased volume will allow the quench spray pumps to operate for approximately four minutes longer than in previous cases, and the increased volume also provides for slightly improved NPSH for the recirculation spray (RS) pumps.
As a result of these facts we have conducted analyses based on an increased outside RS flow of 2250 GPM.
The results show that the containment will depressurize within sixty minutes and remain depressurized even with service water temperature at 87°F.
Analyses have also been conducted at a 35°F service water temperature with satisfactory results.
The available NPSH for the low head safety injection (LHSI) pumps is also improved as a result of increased RWST water volume.
This will provide more assurance that the LHSI pumps will operate without cavitation when they are operated as described in our letter serial no. 374 of August 29, 1977*.
We therefore request that the following limits on operating parameters be approved:
Service Water Temperature Containment Temperature Maximum Containment Air Partial Pressure Minimum Refueling Water Storage Tank Volume l00°F - 125°F
.9.2 PSIA at 87°F service water temperature 45°F RWST temperature.
This value will vary in a manner similar to existing Technical Specification 3.8.
385,200 gallons
e
- VIRGINIA ELECTRIC AND POWER COMPANY TO Mr. Edson G. Case Page No. 2 We are presently taking steps to modify the existing flow restricting orifices in the outside RS pumps to.permit 2250 GPM flow, and we have started work to select the best lo.ng term solutions to the NPSH problem for the RS and LHSI pumps.
We will submit our proposal and schedule for implementing the lo.ng term solutions by November. 22,. 1977*..
Attachment cc:
Mr. James P. O'Reilly Very truly yours, iP. n1. xfJ?ea;.~
C. M. Stallings Vice President-Power Supply and Production Operations