Development of Advanced T-OZON^TM for PWR Decommissioning (2) - 18170

The number of aging nuclear power plants (NPPs) slated for closure around the world has increased. The majority of them are PWRs. Minimization of radiation exposure for PWR decommissioning workers is one of the key factors in decommissioning in order to apply the as low as reasonably achievable (ALARA) principle. To this end, it is desirable to establish a chemical decontamination method to reduce the exposure of PWR decommissioning workers. Toshiba developed T-OZON^TM, a chemical decontamination method for BWRs [1, 2, 3]. To date, the method has been applied more than 90 times in Japanese BWR plants. The reduction in radiation exposure of workers achieved by applying T-OZON^TM is estimated at about 300-2700 man mSv [4]. A major feature of T-OZON^TM is the reduced amount of radioactive waste produced when compared to other decontamination processes. Oxide films on PWR wetted surfaces are harder to decontaminate than those in a BWR due to their chemical composition. To apply T-OZON^TM to PWR oxide films, it is necessary to modify the process conditions. (authors)