ML19309C251
| ML19309C251 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 04/01/1980 |
| From: | Tollison A CAROLINA POWER & LIGHT CO. |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| BSEP-80-591, NUDOCS 8004080357 | |
| Download: ML19309C251 (2) | |
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Carolina Power & Light Company Bruniivick SteEblectr1EPlant P. O. Box 10429 Southport, NC 28461 April 1, 1980 FILE: B3513 SERIAL: BSEP/80-591 Mr. James P. O'Reilly, Director U. S. Nuclear Regulatory Commission Region II 101 Marietta Street, Suite 3100 Atlanta, GA 30303 BRUNSWICK STEAM ELECTRIC PLANT, UNIT NOS. 1 & 2 LICENSE NOS. DPR-71 AND DPR-62 DOCKET NOS. 50-325 AND 50-324 SPECIAL INFORMATION REPORT
Dear Mr. O'Reilly:
At 0949 on February 8, 1980, both Brunswick Steam Electric Plant triaxial time-history accelograph systems alarmed and recorded. The seismic monitoring systems at the Shearon Harris plant, south of Raleigh, NC, and at the University of South Carolina indicated that no seismic activity had occurred.
No seismic-like motion was felt by plant personnel.
The accelographic recordings were examined to evaluate the disturbance, and plant personnel were unable to observe any seismic-related indications.
The seismic monitoring equipment was inspected and no problems were found.
The activities in progress at the time of the event were reviewed and no connec-tion between them and the accelographs could be determined. A thorough search was performed to find something common to both accelograph systems, other than ground. motion, and nothing was found.
The recording of seismic events is initiated by instantaneous accelerations greater than 0.0lg.
These accelerations may result from shocks and vibrations arising from equipment operation and maintenance activities, as well as from seismic events. Seismic-induced ground accelerations of less than 0.02g are masked by normal nonseismic background noise levels that average 0.0lg to 0.015g after the recorder is initiated.
The t eak shock recorder plates, which form a separate passive monitoring system that records the peak accelerations at different frequencies for a seismic event, were also checked and no indication of motion was found.
Plant personnel are capabic of detecting ground accelerations of > 0.03g on this equipment.
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8004080 m
Mr. James P. O'Reilly April 1, 1980 While the seismic monitoring system responses could be similar in a 0.01g to 0.02g seismic event, we believe that such an event did not occur. A seismic event of this magnitude is well below the OBE design value of.08g and would not cause any damage. Such an event would have been felt by many people; however, no motion was detected by anyone.
Es4ed on verification from two independent sources, as well as personnel observations, that no seismic event occurred, and due to the sensitivity of the seismic monitors to initiation by nonseismic events, we feel that the recorders were initiated by a combination of shock and operating vibrations resulting from nonseismic activities.
Th'e printout strips have been sent to Kinemetrics, Inc., Pasadena, CA, for analys is.
They have been asked to provide any information they can from this analysis that would help in verifying the cause of this event.
The instruments have been checked and are fully operational.
Very truly yours, Q
/,/.,
A. C. Tollison, Jr., General Manager Brunswick Steam Electric Plant RMP/sgb cc: '- R. A. Hartfield V. Stello, Jr.
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