ML20210M426
| ML20210M426 | |
| Person / Time | |
|---|---|
| Issue date: | 08/18/1997 |
| From: | Murphy A NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| To: | Knapp M, Ross D, Shao L NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| Shared Package | |
| ML20210M434 | List: |
| References | |
| REF-GTECI-A-46, REF-GTECI-SC, TASK-A-46, TASK-OR GL-88-20, IEIN-97-022, IEIN-97-22, NUDOCS 9708210395 | |
| Download: ML20210M426 (3) | |
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WASHINGTON, D C. 2055H001 August }8, b M
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I MEMORANDUM TO:
Those on Attached List FROM:
Andrew J. Murphy, Chief d4b
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Division of Engineering Technology, RES i
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SUBJECT:
REPOf97"TME MNLP$$)7,1994 NORTHRIDGE i
i EARTHQUAKE - EFFECTS ON ELECTRIC POWER AND
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4 l f Attached fo, your information is a report entitled "The January 17,1994 N0rthridge Earthquake
- Effects on Electric Power and Selected Industrial Facilities." The magnitude 6.7 earthquake
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struck the densely populated San Fernando Valley, in northern Los Angeles, California, at l;
4:31 PST on Monday January 17,1994, causing 57 fatalities, over 16,000 injuries, $20 billion l
l In damage, and widespread power outages. l'his was the second time in 23 years that this i j region has been affected by E. strong earthquake. On February 9,1971, a magnitude 6.6 earthquake occurred about 32 km (20 mi.) northeast of the 1994 epicenter.
lt has been a practice of both the Nuclear Regulatory Commission (NRC) and the Department I
i of Energy (DOE) to sponsor investigatior,3 following a major natural disaster. Lawr,1ce I
Livermore National Laboratory (LLNL) has served as primary contractor for many of the NRC
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and DOE earthquake investigations. The Seismic Qualifications Utility Group (SQUG) and the f
Electrical Power Research Institute (EPRI) also sponsor such investigations on behalf of the utilities. These investigations, which focus on electric power facilities and industrial facilities a.id lifelines containing equipment and structures relevant to NRC and DOE, provide a data j
I base and information to judge the adequacy of seismic design criteria as well as adequacy of i
existing facilities under the purview of the NRC and DOE. One of the major uses of earthquake expt ence data in the ru Jear power industry has been in resolving the Unresolved Safety issue (USI) A-46, " Verification of Seismic Adequacy of Equipment in Operating Plants." Also, ji experience and other test data bases have been used to develop capacity screening tables for the seismic margin methodology and to develop fragilities for seismic probabilistic safety g
assessment (PSA) studies. Use of such data is integrated into the NRC program on Individual N
Plant Examination for External Events (Generic Letter 88-20, Supplements 4 and 5).
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This report on the Northridge earthquake is the first time NRC, DOE, and EPRI reconnaissance efforts were combined to pool resources. There was significant damage following the earthquake. This was to be expected because acceleration records indicate that many facilities experienced motion which exceeded their design values. However, the majority of buildings,
~,Og lifelines, and equipment designed and built using mid-1970s or later se,smic requirements had V
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acceptable structural performance. In most cases, properly designed, detailed, and construc'ed facilities suffered minimal to moderate damage and remained functional after the earthquake.
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PDR TOPRP EXIEPRI lilfllfillfjRllt\\fil]Ifilll ow>eme a
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. Surprisingly, there was considerable damage to steel special moment resisting-frames, Even -
though no steel moment frame buildings collapsed, the observed connection failures were not 3
L expected by most of the structural engineering practitioners. Information Notice No. 97-22,
' Failure of Welded-Steel Moment Resistant Frames During the Northridge Earthquake," alerts
! addressees to factors contributing to these failures.
Earthquake eirects on a large inventory of structures and equipment installations relevant to the electric power industry are also summarized in the attached report. With the exception of high-voltage substation switchyard installations, engineered electrical and inechanical equipment l
. relevant to the electric power industry suffered little damage even at sites that expeiienced the highest ground motion.
Attachment:
As stated I
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Addresses for Memorandum dated Aumst 18,1W7 M. Knapp, RES D. Ross, RES L. Shao, RES M. Cunningham, RES R. Wessman, NRR G. Bagchi, NRR J. Rosenthal, AEOD M. Bell, NMSS J. Larkins, ACRS
'PDR:
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