Patent Number: 052710513
Section: claims

1. In a nuclear reactor comprising a reactor vessel having a reactor core fueled with fuel assemblies, a reactor coolant system circulating coolant through the reactor core, a refueling cavity through which fuel assemblies are inserted into and removed from the reactor core, a spent fuel pit in which fuel assemblies removed from the reactor core are stored under coolant, fuel transfer means through which fuel assemblies are transferred between said refueling cavity and said spent fuel pit under coolant, a refueling water storage tank containing a supply of coolant which fills said refueling cavity during refueling, spent fuel pit cooling means, skimmer means for skimming particulates from the coolant, and purification means for purifying said coolant, the improvement: wherein said spent fuel pit has a volume of coolant for removing decay heat from said fuel assemblies in said spent fuel pit without operation of said spent fuel pit cooling means; wherein said spent fuel pit cooling means is non-safety rated; and wherein said spent fuel pit cooling means and said purification means are connected in series to form a combined cooling and purification system having common non-safety rated pump means and first piping means for circulating coolant drawn from said spent fuel pit through said combined cooling and purification system and back to said spent fuel pit to simultaneously in a single loop cool and purify spent fuel pit coolant; and including second piping means for selectively circulating coolant drawn from said refueling cavity through said combined cooling and purification system and back to said refueling cavity to simultaneously cool and purify refueling coolant in said cavity. 2. The improvement of claim 1 wherein said skimmer means is connected to said first piping means through which coolant is drawn from said spent fuel pit by said common pump means for circulation through said combined cooling and purification system. 3. The improvement of claim 1 wherein said skimmer means is connected to said second piping means through which coolant is drawn from said refueling cavity by said common pump means for circulation through said combined cooling and purification system. 4. The improvement of claim 1 including third piping means disposed between said refueling water storage tank and said second piping means for circulating coolant from said refueling water storage tank through said combined cooling and purification system and back to said refueling water storage tank using said common pump means. 5. The improvement of claim 4 wherein said second piping means and said third piping means have valves for circulating coolant from said refueling water storage tank through said combined cooling and purification system and directly to said refueling cavity without passing through said reactor core using said common pump means. 6. The improvement of claim 1 including transfer means selectively transferring coolant between said refueling cavity and said refueling water storage tank through said combined cooling and purification system without passing through said reactor core using said common pump means. 7. The improvement of claim 1 wherein said combined cooling and purification system comprises parallel branches each having cooling means, purification means and a common pump, and wherein said first piping means comprises common suction pipe means drawing coolant from said spent fuel pit for both branches, and common discharge pipe means discharging coolant from both branches into said spent fuel pit. 8. The improvement of claim 1 wherein said cooling means comprises heat exchanger means. 9. The Improvement of claim 1 wherein said purification means comprises demineralizer means. 10. The improvement of claim 9 wherein said purification means further includes filter means.