DEVELOPMENT OF A CONVENIENT MONITORING METHOD FOR TRITIATED-WATER VAPOR IN AIR USING SMALL WATER DISHES AS PASSIVE SAMPLERS

The distribution of tritiated water (HTO) vapour in working areas was investigated in connection with leakages from both a heavy water facility set adjacent to the core of the Kyoto University Research Reactor (KURR) and a tritium target used as a neutron generator in the Kyoto University Critical Assembly (KUCA) building. In both cases a monitoring method was developed and applied for estimating the HTO vapour concentration in air using laboratory dishes which contained a few tens of millilitres of tap water. This technique was found to serve not only for acquiring information on HTO concentration distributions in the containment building air but also for determining the leak point, followed by taking measures for radiation protection based on the ALARA concept.