Probability of failure in BWR reactor coolant piping: Volume 1, Summary report
This report summarizes a probabilistic reliability evaluation of BWR reactor coolant piping performed for the US Nuclear Regulatory Commission (NRC) by the Lawrence Livermore National Laboratory (LLNL). In this evaluation, LLNL estimated the probability of a double-ended guillotine break (DEGB) in the main steam, feedwater, and recirculation loop piping of a representative Mark I BWR plant. Two causes of pipe break were considered: crack growth at welded joints, and the earthquake-induced failure of supports for piping and components. A probabilistic fracture mechanics model, including intergranular stress corrosion cracking (IGSCC) in Types 304 and 316NG stainless steels, was used to estimate the probability of crack-induced pipe break. The probability of pipe break indirectly caused by support failure was estimated by applying reliability techniques to supports for ''heavy components'' such as the reactor pressure vessel, as well as to conventional pipe supports such as spring hangers and snubbers. Our probabilistic fracture mechanics evaluation found that the probability of crack-induced DEGB in main steam, feedwater and, if IGSCC is not a factor, recirculation piping is very low. In ISGCC-susceptible Type 304SS piping, stress corrosion dominates the probability of DEGB due mainly to cracks that initiate during the first few years of plant life; replacing Type 304 piping with IGSCC-resistant Type 316NG lowers DEGB probabilities by several orders of magnitude. We also found that the probability of pipe break caused by seismically-induced support failure is low regardless of whether ''heavy component'' supports or conventional pipe supports are being considered. 23 refs., 34 figs., 16 tabs.
- Research Organization:
- US Nuclear Regulatory Commission (NRC), Washington, DC (United States). Div. of Engineering; Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6163118
- Report Number(s):
- NUREG/CR-4792-Vol.1; UCID-20914-Vol.1; ON: TI89008911
- Country of Publication:
- United States
- Language:
- English
Similar Records
Probabilistic analyses of failure in reactor coolant piping. [Double-ended guillotine break]
PRAISE-C. LWR Piping Reliability Assessment
Related Subjects
22 GENERAL STUDIES OF NUCLEAR REACTORS
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
BWR TYPE REACTORS
REACTOR COOLING SYSTEMS
FAILURES
PROBABILITY
PIPES
PWR TYPE REACTORS
CRACK PROPAGATION
CRACKS
FRACTURE PROPERTIES
INTERGRANULAR CORROSION
REACTOR SAFETY
SEISMIC EFFECTS
STAINLESS STEELS
STEAM LINES
STRESS CORROSION
SUPPORTS
WELDED JOINTS
ALLOYS
CHEMICAL REACTIONS
COOLING SYSTEMS
CORROSION
ENERGY SYSTEMS
HIGH ALLOY STEELS
IRON ALLOYS
IRON BASE ALLOYS
JOINTS
MECHANICAL PROPERTIES
MECHANICAL STRUCTURES
REACTOR COMPONENTS
REACTORS
SAFETY
STEELS
WATER COOLED REACTORS
WATER MODERATED REACTORS
210100* - Power Reactors
Nonbreeding
Light-Water Moderated
Boiling Water Cooled
210200 - Power Reactors
Nonbreeding
Light-Water Moderated
Nonboiling Water Cooled
220900 - Nuclear Reactor Technology- Reactor Safety
990230 - Mathematics & Mathematical Models- (1987-1989)