ML19270G938
| ML19270G938 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 06/18/1979 |
| From: | Brown S VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| 491, NUDOCS 7906210233 | |
| Download: ML19270G938 (3) | |
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7 VIRGINI A ELECTRIC AND POWER COMP ANY, RICNMOND VIRGINI A 23261
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June 18, 1979 Mr. James P. O'Reilly, Director Serial No. d91 Office of Inspection & Enforcement PSE&C/MGD/CGC:mac: wang U. S. Nuclear Regulatory Comission Docket No.60-339 Region II 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303
Dear Mr. O'Reilly:
On June 13, 1979, a report was made under the provisions of 10CFR50.55(e) concerning incorrectly sized orifices in the piping of the recirculation spray system of North Anna Power Station Unit 2.
In accordance with the reporting requirements of 10CFR21, the following information is submitted:
- d. Name and address of reporting individual:
Mr. E. A. Baum, Executive Manager Licensing & Quality Assurance Virginia Electric and Power Company P. O. Box 25566 Richmond, Virginia' 23251 B.
Facility, activity and/or component affected:
North Anna Power Station, Unit 2 Recirculation Spray System C.
Name of firm constructing the facility or supplying the component, activity or service:
Stone & Webster Engineering Corporation P. O. Box 2325 Boston, Massachusetts 02107 y9y D.
Description of defect, deficiency, or failure to comoly:
In May 1975, Engineering & Design Coordination Report (ESTR) P-N9 required restriction orifices to be placed in tSe discharge pioing of the Unit I and Unit 2 Outside Recirculation Spray Pumps.
This flow restriction was needed to limit the net positive suction head (NPSH) required by these pumps.
Later safeguards analysis indicated a reduction in NPSli available to the pumps, so casing cooling modifications were developed to provide adequate NPSH. An interim modification was made to Unit 1. which included resizing the restriction orifices required by E&DCR P-688.
E&DCR P-2068 changed the bore diameter of the Unit 1 orifices for the 7906210 M3
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Mr. James P. O'Reilly, Director 2
interim modification, and E&DCR P-2058A revised the orifice diameter based on subsequent information.
ELOCR P-2058A stated the restriction orifices should be removed for the permanent casing cooling modification, and E&DCR P-2058B was generated to require the restricting orifices be bored to full pipe diameter after the permanent modification was completed in Unit 1 Since Unit 2 did not require the interim modification, E&DCR's P 9058, P-2068A, and P-2058B were written for Unit 1 only. The Casing Cooling System E&DCR review included a review of the E&DCR P-2058 series; however, the information generated in the P-2058 series did not address Unit 2 and was therefore considered not td affect Unit 2.
E&DCR P-688, as it was written in May 1975, was covered by the site E&DCR review. As this E&DCR was prepared for both Unit 1 and Unit 2, it satisfied the requirements of the review and was determined to be acceptable.
Since there was no reference to P-688 on the E&DCR P-2068 series, the fact that the restriction orifices required by P-583 were not bored to full Dipe diameter, as required by P-20683, was not recognized, and a separate E&DCR to increase the Unit 2 orifice to full bore was not issued. This is considered to be an isolated incident and not a breakdown in the E&DCR program.
E.
Date of determination of reportability:
June 13, 1979 F.
Similar components, activities, or services:
None G.
Corrective action which has been, is being or will be.taken, and individual responsible and the length of time to complete the action:
The restriction orifies installed in the Unit 2 piping have been replaced by an orifice bored to full pipe diameter.
H.
Other information:
None Since no other actions will be required to correct the problem described in section D of this report, we consider this to be the final report under the provisions of 10CFR50.55(e)(3).
2239 294
Mr. James P. O'Reilly, Director 3
Should you require further information, please contact this office.
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