« lessĬurrent probabilistic risk assessment (PRA) methods for nuclear power plants utilize seismic ''fragilities'' - probabilities of failure conditioned on the severity of seismic input motion - that are based largely on limited test data and on engineering judgment. The important observations made in the process of data analysis are included in this report. Ultimately, each fragility level is expressed in terms of a single descriptor called an HCLPF value corresponding to a high (95%) confidence of a low (5%) probability of failure. The resulting parameters are presented in terms of a median value, an uncertainty coefficient and a randomness coefficient.
The zero period acceleration and the average spectral acceleration over a frequency range of interest are separately used as the single g-value. To this end, a single g-value has been selected to approximately represent the test vibration level and a statistical analysis has been performed with the g-values corresponding to a particular failure mode.
In addition, the test data have been analyzed for determination of the respective probabilistic fragility levels. Fragility levels have been determined for various failure modes more » of each equipment class and the deterministic results are presented in terms of test response spectra. The data evaluation of four equipment families, namely, motor control center, switchboard, panelboard and power supply has been completed. In Phase II of the program, BNL has collected additional test data, and has further advanced and is applying the methodology to determine the fragility levels of selected essential equipment categories. In Phase I of the Component Fragility Program, Brookhaven National Laboratory (BNL) has developed a procedure to establish the seismic fragility of nuclear power plant equipment by use of existing test data and demonstrated its application by considering two equipment pieces. of Engineering Brookhaven National Lab., Upton, NY (United States) Sponsoring Org.: USNRC Nuclear Regulatory Commission, Washington, DC (United States) OSTI Identifier: 5420393 Report Number(s): NUREG/CR-4659-Vol.4 BNL-NUREG-52007-Vol.4 ON: TI91016471 DOE Contract Number: AC02-76CH00016 Resource Type: Technical Report Country of Publication: United States Language: English Subject: 22 GENERAL STUDIES OF NUCLEAR REACTORS NUCLEAR POWER PLANTS SEISMIC EFFECTS REACTOR COMPONENTS ELECTRICAL EQUIPMENT ENGINEERED SAFETY SYSTEMS REACTOR CONTROL SYSTEMS REACTOR INSTRUMENTATION REACTOR SAFETY RELAYS RELIABILITY SWITCHES CONTROL SYSTEMS EQUIPMENT NUCLEAR FACILITIES POWER PLANTS SAFETY THERMAL POWER PLANTS 220900* - Nuclear Reactor Technology- Reactor Safety 220200 - Nuclear Reactor Technology- Components & = , Publication Date: Research Org.: Nuclear Regulatory Commission, Washington, DC (United States).
0 kommentar(er)
