ML19350A641
| ML19350A641 | |
| Person / Time | |
|---|---|
| Site: | Atlantic Nuclear Power Plant  |
| Issue date: | 03/02/1981 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Collier A OFFSHORE POWER SYSTEMS (SUBS. OF WESTINGHOUSE ELECTRI |
| Shared Package | |
| ML19350A644 | List: |
| References | |
| NUDOCS 8103160600 | |
| Download: ML19350A641 (1) | |
Text
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NUCLEAR REGULATORY COMMI ION V, s 3
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MAR 21981 A
On In Reply Refer Tw:
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o Of fshore Power Systems ATTN:
A. R. Collier, President P. O. Box 8000 Jacksonville, FL 32211 Gentlemen:
The enclosed IE Circular No. 81-03 is forwarded for your information. No written response to this Circular is required. If you have any questions related to this matter, please contact this office.
Sincerely, James P. O' Reil Director
Enclosures:
1.
IE Circular No. 81-03 2.
List of Recently issued IE Circulars i
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SSINS Ny..
6330 Accession No.:
8008220271 IEC S1-03 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHIN3 TON, D.C.
20555 March 2, 1981 IE Circular No. 81-03: INOPERABLE SEISMIC MONITORING INSTRUMENTATION Descriction of Circu stances:
On N0venber 8, 1930, an earthquake occurred off the ccast near Eureka, California.
The earthquake was reported to have a magnitude of 7.0 on the Richter Scale at the epicenter, app.oximately 25 to 75 miles from the Hu.boldt Bay Po-er Plant facility.
There were 12 separate seismic events above a cagnitude of 3.5 that occurred within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of the earthpuake, the largest event reasuring 5.2.
Reported damage to structures included several houses that were moved off supporting posts, various chimneys that were knocked do-n, one high-ay overpass that collapsed, and unspecified damage that occurred at two pulp mills.
There were three potentially different sources of plant response data: three sets of eagnetic tape triaxial accelograph recorders; three sets of triaxial film recorders (passive device); and one set of triaxial response spectrue recorders (passive device).
A review of the records from these instruments indicated the following: the magnetic tape triaxial recorders did not produce useful records due to a degraded Ic.<-voltage po er supply in the recording syste-(pre,'iously scheduled for routine servicing one week after the earthquake);
a buildup of dirt and dust appeared to eake inoperable six of the nine film recorders (the readings from the other three are considered highly unreliable and were not obtained fro: the same set of triaxial recorders); the triaxial response spectrun recorder was the only instru ent believed to produce reliable data.
On January 24, 1950, an earthquake ceasuring 5.5 on the Richter Scale occurred l
about 10 miles north of Lawrence Liverecre Laboratory (near San Francisco, California).
Numerous aftershocks also occurred with one reasuring 5.2 on January 26.
The damage to civil structures was considered minor.
Rancho Seco Nuclear Plant, located approximately 45 miles northeast of the earth-quake area, reported no physical damage, although plant personnel felt slight building motion.
Rancho'Seco was shutdown for refueling during these earthquakes.
During this period, the electrical seismic instru entation system was inoperable because portions of the system were out for calibration.
For the other instruments, power was not being supplied due to electrical cable orcblens.
Whether tha l
seismic instru entation would have a U.S. Geological Survey equipment clo from a passive recorder sho-ed peak DUPLICATE DOCUMD;T i
Entire docunent previously entered into syste:n unde..
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