ML19312E146
| ML19312E146 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 05/28/1980 |
| From: | Tollison A CAROLINA POWER & LIGHT CO. |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| BSEP-80-920, NUDOCS 8006030352 | |
| Download: ML19312E146 (2) | |
Text
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Teltcopitd to John Hanna (NRC)
M.ty 28, 1980 mmmq L"u d
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Carchna Power & Light Company Brunswick Steau Electric Plant P. O. Box 10429 Southport, NC 28461 May 28, 1980 FILE:
B09-13516 SERIAL: BSEP/80-920 Mr. James P. O'Reilly, Director U. S.%Eu-lear Regulatory Cctmission Region II, am e alug-101 Marietta Street N.W.
Atlanta, GA 30303 BRUNSWICK STEAM ELECTRIC PLANT, U?IT NOS. 1 & 2 LICENSE NOS. DPR-71 AND DPR-62 DOCKET NOS. 50-325 AND 50-324 SPECIAL REPORT ON SCRAM DISCHARGE VOLUME FLOAT SWITCHES
Dear Mr. O'Reilly:
As requested in a conference call on May 22, 1980, between Messrs. John Hannon (ONRR), Bill Mills (OIE), Paul Kellogg (Region II), and Messrs. Morris Brown, Sam Bohanan, Jim McQueen (Carolina Power & Light Company), the Brunswick Steam Electric Plant (BSEP) submits the following information on the Unit No. 1 scram discharge volume float switch failure on November 14, 1979.
During a reactor scram on October 19, 1979, the scram discharge volume drain valve did not close in the required time, causing a wat,er hammer event which damaged several pipe supports on the scram discharge volume discharge piping (LER 2-79-74).
The valve was positioning itself in the "close" position in five minutes vice the required lers than 30 seconds due to a faulty solenoid controlling the air supply to the valve.
The damaged pipe supports were repaired.
Based on the nonavailability of parts to repair or replace the drain valve solenoid, it.was decided to start up on November 13, 1979, with the vent and drain valves closed to prevent possible damage from a scram.
Operatiens per-sonnel were to monitor the scram discharge volume by periodically draining, as necessary, when the " Scram Discharge Volume Not Drained" alarm annunciated at 39 gallons. A rod block is designed to actuate at 69 gallons and a reactor scram occurs at 109 gallons. At 0616 on November 14, 1979,.the Unit No. 1 reactor scra=med from 4% power during a heatuo on a high scram discharge volume level (109 gallons) without receivinh Jte high level alarm or the rod block.
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c Mr. James P. O'Reilly May 28, 1980 An inspection of the level switches, Magnetrol Model 50-751, revealed that the,
float ball on the rod block switch was crushed and the float ball stem on the high level switch was bent such that the switches would not work.
The damaged float ball and stem were replaced and the switches calibrated'and tested satis-factorily. The remaining four switches and float assemblies on Unic No. 1 and all six assemblies on Unit No. 2 were inspected with no problems found.
It is believed that the water hammer event from the October 19, 1979, acram caused the failure of the two switch assemblies.
A replacement solenoid to repair the scram discha rge volume drain valve was located at the Hatch Plant (Georgia Power & Light Company), flown to BSEP, and installed. The valve was tested satisfactorily and the scram discharge volume vent and drain system was returned to a normal lineup. A periodic test has been established to test the high level alarm and the rod block function of these switches. Also, a Maintenance Instruction has been prepared to perform a periodic functional test of the scram discharge volume vent and drain valves'.
We trust that this information satisfies the concerns expressed on the failure of these switches.
If you have any additional questions on this matter, please contact a member of my staff nr me.
Very truly yours, A. C. Tollison, Jr., General Manager Brunswick Steam Electric Plant RMP/sgb, 1-cc:V Mr. R. A. Hartifeld Mr. V. Stello, Jr.
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