Patent Number: 043472141
Section: claims

1. An apparatus for detecting the location of failed fuel by analyzing tag gas consisting of rare gas released in cover gas from the failed fuel, said rare gas being at least one from the group consisting of Xenon and Krypton, comprising: (a) tag gas collection/enrichment means including at least two activated-charcoal adsorption columns for collecting tag gas from cover gas at an ambient temperature and for enriching said collected tag gas to an analyzable concentration, said columns being connected and being progressively smaller in volume in accordance with the increase in the degree of enrichment of the tag gas to an analyzable concentration;  (b) a line for introducing said cover gas containing tag gas into said tag gas collection/enrichment means;  (c) tag gas analysis means for analyzing said enriched tag gas to determine the composition thereof;  (d) a line for supplying said enriched tag gas to said analysis means; and  (e) a line for transmitting residual gas from which said collected gas is separated to a cover gas clean-up system.  (a) tag gas collection/enrichment means including a storage tank for collecting the cover gas containing tag gas and a selectively gas-permeable membrane means including a selectively gas permeable membrane formed from one from the group consisting of silicone rubber, porous metal, porous ceramic and tetrafluoroethylene for selectively permeating tag gas at the ambient temperature;  (b) a line for introducing said cover gas containing tag gas into said tag gas collection/enrichment means;  (c) tag gas analysis means for analyzing said enriched tag gas to determine the composition thereof;  (d) a line for supplying said enriched tag gas to said analysis means; and  (e) a line for transmitting residual gas from which said collected gas is separated to a cover gas clean-up system. 2. An apparatus according to claim 1, wherein each said ambient-temperature activated-charcoal adsorption column is provided with a heater for desorbing adsorbed tag gas. 3. An apparatus according to claim 1, wherein said ambient-temperature activated-charcoal columns are operated within a temperature range of 0.degree. C. to 60.degree. C. to adsorb tag gas. 4. An apparatus according to claim 2, wherein the adsorbed tag gas is removed by heating to at least 300.degree. C. by means of said heater. 5. An apparatus according to claim 1, wherein said ambient-temperature activated-charcoal columns are multi-stage arranged in series with one another. 6. An apparatus according to claim 1, wherein said ambient-temperature activated-charcoal columns are multi-stage arranged in parallel with one another and are each provided with a storage tank for desorbed gas, said apparatus further comprising a line for transmitting desorbed gas from each said activated-charcoal adsorption column to each corresponding storage tank and a line for refluxing gas from said storage tank to said activated-charcoal adsorption column. 7. An apparatus according to claim 5, wherein said gas separator is operated within a temperature range of 0.degree. C. to 60.degree. C. to permeate the tag gas selectively. 8. An apparatus for detecting the location of failed fuel by analyzing tag gas consisting of rare gas released in cover gas from the failed fuel, comprising: