Accident analysis of evaporation to dryness by boiling of reprocessed high level liquid waste at fuel reprocessing facilities with considering severe accident measures

Yoshida, Kazuo 

An accident of evaporation to dryness by boiling of high level liquid waste is postulated as one of the severe accidents caused by the loss of cooling function at a fuel reprocessing plant. In this case, some amount of fission products (FPs) will be transferred to the vapor phase in the tank, and could be released to the environment. Two mitigative accident measures have been proposed by the licensee. One of them is injecting cold water to waste tanks to prevent dryness and another is leading generated vapor through temporary duct to huge spaces in the facility to condense to liquid. Thermal-hydraulics and aerosol transport behaviors in compartments of a typical facility building have been analyzed based on the scenario with these accident measures. The effects of measures are discussed form a view point of the reduction of radioactive material release to environment.