ML20030C226
| ML20030C226 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 08/18/1981 |
| From: | Spencer W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, 457, NUDOCS 8108250536 | |
| Download: ML20030C226 (2) | |
Text
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e VIRGINI A ELE RIC AND PO Eg COMP AN pf 23261
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Mr. James P.
O'Reilly, Director Serial No. 457 Office of Inspection and Enforcement PSE&C/WBR:bw U.S.
Nuclear Regulatory Commission Region II 101 Marietta Street, Suite 3100 Docket No. 50-404 Atlanta, Georgia 30303
Dear Mr. O'Reilly:
This letter is intended to close out the 10CFR50.55(e) item reported to the NRC on September 15, 1978.
5-day letter (Serial No. 531) was Pursuant to 10CFR21, a
submitted on September 20, 1978.
The subject of the report was a deficiency in the design of the recirculation spray (RS) pump / low pressure core l
l injection operational mode for North Anna Unit 3 For a LOCA, one required mode or operation for a RS pump is to maintain continuous core injection following the initial core injection l
by the Low Pressure Injection (Decay Heat Removal) system.
For the recirculation mode of operation, the B&W system description states that a flow of approximately 3,000 gpm is requ ad at a reactor vessel backpressure of 100 psig.
With the t rent design, a flow of approximately 2,300 gpm at 100 psig backpressure, is available for core injection.
Since the time of our original report, Stone &
Webster Engineering Corporation and Babcock and Wilcox Company have conducted a review of the design criteria for the Emergency Core Cooling Systems.
During the review, it was established that the control valves for the HPI pumps could be set to ensure the HPI pumps could operate dcwn to a zero reactor vessel backpressure.
With the added flow from the HPI pumps at these lower pressures, it was concluded that the performance of the RS pumps in the sump recirculation mode is acceptable providing the HPI is left operating until the HPI flow is exceeded by that of the recirculation spray pumps.
The B&W system descriptions will be amended to reflect these changes.
0108253536 810818 j[/b5 PDR ADOCK 05000404 S
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Mr. O'Reilly SHEETNO.
vincisiA sticinic Aso powen coupANY vo This is our final report on this item.
Should you require additional information, please advise.
Very truly yours,
"/swf W.
. Spencer Vice President - Power Station I
Engineering and Construction Services cc: Mr. Robert L. Tedesco Division of Liecnsing l
i o
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