Summary report on the Seismic Safety Margins Research Program

Technical Report · Wed Jan 01 04:00:00 EST 1986

OSTI ID:6188540

Cummings, G E

The Seismic Safety Margins Research Program (SSMRP) was a program to develop a complete, fully coupled analysis procedure (including methods and computer codes) for estimating the risk of an earthquake-induced radioactive release from a commercial nuclear power plant. The SSMRP was the first effort to trace seismically induced failure modes in a reactor system down to the individual component level, and to take into account common-cause earthquake-induced failures at the component level. This report summarizes methods and results generated by SSMRP. The SSMRP method makes use of three computer codes, HAZARD, SMACS and SEISIM to calculate ground motion acceleration time histories, structure and component responses and failure, and radioactive release probabilities. To demonstrate the methodology, an analysis was done of the Zion Nuclear Power Plant. The median frequency of core melt was computed to be 3E-5 per year, with upper (90%) and lower (10%) bounds of 8E-4 and 6E-7 per year. The main contribution to risk came from earthquakes about 2 through 4 times the design basis earthquake level. Risk was dominated by structural and inter-building piping failures and loss of off-site power. Sensitivity studies were undertaken to test assumptions and modeling procedures relative to soil-structure interaction effects, feed-and-bleed cooling, and structural failures. Assumptions made could have an order-of-magnitude effect on core melt frequency. Also, guidelines were developed for simplifying the SSMRP method, and importance rankings were generated based on the Zion analysis. 56 refs., 6 figs.

• Research Organization: Lawrence Livermore National Lab., CA (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6188540
• Report Number(s): NUREG/CR-4431; UCID-20549; ON: TI86004897
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
220900* -- Nuclear Reactor Technology-- Reactor Safety
ACCIDENTS
COMPUTER CODES
EARTHQUAKES
ENRICHED URANIUM REACTORS
FAILURES
LOSS OF COOLANT
NUCLEAR FACILITIES
NUCLEAR POWER PLANTS
POWER PLANTS
POWER REACTORS
PWR TYPE REACTORS
RADIATION ACCIDENTS
REACTOR ACCIDENTS
REACTORS
RISK ASSESSMENT
SEISMIC EFFECTS
SEISMIC EVENTS
SENSITIVITY ANALYSIS
SOIL-STRUCTURE INTERACTIONS
THERMAL POWER PLANTS
THERMAL REACTORS
WATER COOLED REACTORS
WATER MODERATED REACTORS
ZION-1 REACTOR
ZION-2 REACTOR