ML20004F830
| ML20004F830 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek, Cooper, Arkansas Nuclear, River Bend, Waterford, South Texas, Comanche Peak, Fort Calhoun, Fort Saint Vrain, Perkins  |
| Issue date: | 03/04/1981 |
| From: | Madsen G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| NUDOCS 8106220487 | |
| Download: ML20004F830 (1) | |
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MEMORAt'0UM FOR: Those Listed Below FROM:
G. L. Madsen, Chief, Reactor Projects Branch, RIV
SUBJECT:
IE CIRCULAR NO. 81-03 Subject IE Circular has been sent to the following licensees. A copy is attached for your information.
Arkansas Power & Light Com p ni Texas Utilities Generating Company ANO-1 & 2 (50-313, 50-368)
Ccmanche Peak 1 & 2 (50-445, 50-446)
Nebraska Public Power District Gulf States Utilities Cooper Nuclear Station (50-298)
River Bend 1 & 2 (50-458, 50-459)
Omaha Public Power District Houston Lighting and Power Company Ft. Calhoun Nuclear Station (50-285)
South Texas 1 & 2 (50-498, 50-499)
Public Service Company of Colorado Louisiana Power and Light Company Fort St. Vrain (50-267)
Waterford-3 (50-382)
Kansas Gas and Electric Ccmpany Wolf Creek (STN 50-482)
.$$T}%W d.L.Madsen, Chief Reactor Projects Branch
Attachment:
As stated DISTRIBUTION:
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SSINS No.: 5830 Accession No.:
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20555 IE Circular No. 81-03 March 2, 1981 Page 1 of<3 l
INCPERABLE SEISMIC MONITORING INSTRUMENTATION Descrhtion of Circumstancas:
On November 8,1980, an earthquake occurred off the coast near Eureka, California.
The earthquake was reported to have a magnitude of 7.0 on the Richter Scale at' the epicenter, approximately 25 to 75 miles from the Humboldt Bay Power Plant facility.
There were 12 separate seismic events above a magnitude 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 earthquake, the-largest event measuring 5.2.
-Reported. damage to structures included several houses that were moved off supporting posts, various chimneys that were knocked down, one hignway ourpass that collapsed, and unspecified damage that occurred at two pulp mills.
There were three potentially different sources of plant response data: three sets of magnetic tape triaxial accolograph recorders; three sets of triaxial film recorders (passive. device); and one set of triaxial response spectrum recorders (passive device). -A review of the records from these instruments indicated the fallowing: the magnetic tape triaxial recorders did not produce useful records due to a degraded low-voltage power supply in the recording systen (previously scheduled for routine servicing one week after the earthouake);
a buildup of dirt and cust appeared to make inoperable six of the nine film recorders (the readings from the other three are considered nighly unreliable and were not ootained from the same set of triaxial recorders); tne triaxial response spectrum recorder was the only instrument believed to produce reliable data.
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On January 24, 1980, an earthquake measuring 5.5 on the Richter Scale occurred acout 10 miles north of Lawrence Livermore Lacoratory (near San Francisco, California). Numerous aftersnocks also occurred witn one measuring 5.2 on
. January 25. The damage to civil structures was consicered minor.
Rancno Seco Nuclear Plant, located approximately 45 miles northeast of the eartn-cuata area, recorted no physical damage, althougn plant nrsonnel felt slight building motion.
Rancho Seco was shutdown for refueling curing these eartnquakes.
During this period, the, electrical seismic instrumentation system was incoerable because portions of the system were out for calibration.
For the other instruments,
. power was not being suco'f ed due to electrical cable proolems. Whether the seismic instrumentation would have activated or not is unclear cecause the b.S. Geological Survey eouipment close to the site cic not trigger.
Recorcs from a passive recorcer snowed peak accelerations from 1 to 1.5 g and 0.1 g 1
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