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

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17 .. ~-~•. Nuclear Waste Orsposal Crrsrs the frequency of these spent fuel pool peal failures should warrant heightened attention, especially as mute and mute irradiated foe! assemblies are placed into the spent fuel pools. _ ~~Loss of Cooling ~' ' The inability uE the fuel pouf cooling system ur its backups to remove the decay heat from the spent fuel pool poses an indirect challenge to public health. ' and safety. The water in the spent fuel pout serves as a heat sink that provides time to restore fuel pool cooling prior to the spent fuel pool boiling. The boiling. . spent fuel pool produces a slow, sustained water inventory loss from the pooLAs~ long as the boiling spent fuel pool's water level is maintained above the top of the _ irradiated fuel assemblies, these assemblies will be adequately cooled. Howev - the consequences From spent fuel pool boiling un the remainder of the plant tan ~ be extremely adverse as discussed in Chapter 9. ' '~ Fuel pool cooling can be lost for a large number of causes. Several inddents are described in Appendix A. As with the water inventurv fuss events, the pri~~- ~~ mary cause fur loss of spent fuel pool cooling events has been the failure of a non_, `~ --. ~ j emerency System ur component. The loss of spent fuel pool cooling frequently; ;,x' <~~' I~ remained undetected for several hours. The time that the spent fuel pool cooling ;; failure goes undetected is important because federal regulations do not mandate' - ' '- a minimum time for the spent Euel pout water to reach boiling following loss of '_.•~ . ~ cooling, and it can require considerable time to restore fuel pool cooling. Thus, . ~ the spent fuel pool water can potentially heat up while a loss of cooling event remains undetected such that the pool boils before cooling can be restored. The severe consequences from spent fuel pool boiling are described in Chapter 9. Radiation Overexposure :~- The water in spent fuel pools serves as a cooling medium to remove decay heat and as a shielding mechanism against the highh• radioactive spent fuel.,.; assemblies. The spent fuel pool water inventurv loss e~•ents previously desaibed;~ involved the potential for ndiatiun u~•erexposure as the shielding pro~d~ bY.;; the water was eliminated, but the follu~~•ing events and similar events summa- rised in Appendix A involve potential and actual radiation overexposure that-'~ -occurred even though the required tipent fuel pool avater level was maintained- ~ 't. The health physics (HPl technicians at the Bro~~•ns Ferrv i`ludear Plant were ; instructed during the summer of 1950 nut to use portable teletectors to obtain.;t ~untact ~{use rates fur spent toe! assemblies. l'urtable teletectors are hand-held ray{lotion muniton with a probe muunte~i at one en~i of a lung aluminum tube and the readout at the other end. Appar~ntl~~, HP technicians at other plants had ;l dipped the probe into the spent fuel purl to determine the ray{iuauti~•ity le~'el of ;pint foe! assemblies. The hullu~~~ alununLrm tubes un the teletectors displaced the ~.•ater, significantly re~iucur~ the >hiel~iin~ fa~tur an~1 pru~•iding a stream1nS 4'. -~. `t:':,. ~`Y~ .~f;_.. »;`"~._ . ~~,. i~6