Agenda - 11-17-1998 - 5a - Laserfiche WebLink

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1.1 Nuclear Wasre Disposal Cns~s accident e+•erv 60,UO1) years given the lUy plants Lvrrently operating. Due to the accident's perceived low probability, the I~RC concluded that it represented an acceptable nsk to public health and safety despite the severe consequences. The 1leart of probabilistic risk assessment IPRA) is statistical analysis. Such ciphering has valuable applications, but PRA proponents quantifying nuclear safety risks should consider the fief that a SRC statistician published this c~n- clusion un Vlarch 9, 1979: The probability is less than 0.~ that the next (i.e.. the first) major accident occurs within the next-100 reactor vein. The probability is less than .0. that the next major accident occurs in the next 21 reactor years. The probability is larger than 0.~ that the next major accident will occur after the next SOU reactor years." The major accidcr~t•at Three IV[ile Island Unit 2 occurred on March 3b, 1979- fe++•er than 500 hours later. The primary faults of PRAs include nut addressing all credible initiating e+•ents and using invalid assumptions. (t is exceedingly difficl-lt to co+•er every conceivable failure mule and effect in a PRA for something as complex as a nuclear power plant. According to a consultant to the ~iRC who reviewed Individual Plant Examinations featuring PRA, "attention to detail makes sate plants-lack of attention to details kills people."~ The nuclear power industn• has nut evaluated the integrated risk from nuclear pu~ver plant operation with the on-site storage of significantly more spent fuel assemblies than had been considered +vhen the plants +~•ere designed. Spent fuel risk assessments assume that only one-third of a reactor core's inven- turv ++•ill be damaged, vet spent fuel pools now contain up++ards of seven reactor cures of irradiated fuel assemblies as shown in Table i-l. These details demand proper attention. The spent fuel rises sessments dismiss the se+•ere consequences from a spent fuel accident primarily due to the perceived lung time that the operating staff his to perform mitigating actions. However, these risk assessments fail to account fur the single must important element in any mitigation effort-name!v, the problem's detection. The instrumentation used to monitor spent fuel pool temperature and level is almost al+vavs nonemergencv equipment. This means that it is nut designed, procured, installed. maintained. or tested with the same high standards applied to emergency system components to guarantee their per- furmance. As repeatedly illustrated by the fulluwin~; incidents, the initiating e+~ent frequently Sues undetected fur hours ur even days due to inoperable spent fuel pout instrumentation. It seems prudent, if nut mandaturc, to pnn•ide reason- ,ible a~sur,~nce that spent fuel pu~~l hr~~blrm~ ~~ III be readily detected before their ~r.~~•e cun.e~luence~ are disrmr. ed h,i~+•~1 .,n remedi<il actuuu. r;p