Nuclear Desalination Reactor Probabilistic Safety Analysis Technology Applied Research

Nuclear power can be a cheap energy source for seawater desalination, it can solve the problems produced by the energy structure. Nuclear desalination reactor(NDR) must be built in a area with thick population and without emergency plan out of the plant, so the request for risk frequency must be less than 10-7/year which can be ensured by probabilistic safety analysis(PSA). Additionally, because of the NDR'S particular design and running characterization, such as the passive designed engineered safety features, as a result the PSA technology of NDR and especially the reliability evaluation method of passive systems quest for farther research, therefore studying the technology of NDR'S PSA and the reliability evaluation method of passive systems will be significant.This paper first studies the design and running characterization of NDR and analyse the PSA technology of present nuclear power plant , and then put forward a research thought of NDR which is connecting the consequence of event sequence with the radioactive release classification and then define it. The adaptive monte-carlo method was put forward after a research of passive physical process failure probability evaluation method. and then it was applied to the passive system of NDR under LOCA condition according to its characterization, finally the probability of passive system was integrated to the LOCA PSA mode, which was finally quantified by the small event tree and large fault tree method.NDR'S PSA found that LB4 frequency is 5.45E-08 which is the largest of all the radioactive release classification under LOCA condition, it is far less than core damage frequency 10-5 of the present improved second generation nuclear power plant . The failure probability of passive systems is 9.0E-04 under lager LOCA and passive physical process failure probability account for 1.10%, as to LB2 and LB4, it respectively account for 0.92% and 1.10%. The quantitative analysis of NDR find out the weakness of the system are the isolation valve setting on each injecting pipe , if the reliability of the isolation increase tenfold, the reliability of passive system will be raised by 88.9%, at the same time the frequency of LB4 reduce to 5.4E-09.