DETERMINATION OF THE ATMOSPHERIC HTO CONCENTRATION AROUND THE NUCLEAR FUEL REPROCESSING PLANT IN ROKKASHO BY USING A PASSIVE TYPE SAMPLER

In order to study the areal distribution of (3)H in the atmosphere around the spent nuclear fuel reprocessing plant in Rokkasho, Japan, we developed a passive type sampler of atmospheric water vapor and tested its usability in the field. A polyethylene bottle with a porous polyethylene membrane at the opening was used as the sampler. The bottle contained 300 g of molecular sieve 3A (MS-3A) for adsorbing water vapor passing through the membrane. The concentration of (3)H in water recovered from the MS-3A in the bottle was compared with that obtained by an active type sampler. Both (3)H concentrations agreed well with each other, which showed that the method developed was practical and effective. Using the passive type samplers at nine sampling points around the nuclear fuel reprocessing plant in November and December 2007, we successfully obtained the monthly areal distributions of (3)H concentrations in the atmospheric water vapor.