Study on safety evaluation under severe accidents in fire at fuel reprocessing facilities

Tashiro, Shinsuke 

In such as reprocessing facilities, radioactive materials with easy scattering into air are usually treated in the Glove-box (GB). Under the fire accident with GB panels burning, radioactive materials and soot will be together released within the facilities. When the high efficiency particle air (HEPA) filter in the ventilation system, which plays role of the confinement equipment for radioactive materials within the facilities, is damaged during such accident, it may lead to enhance the release of radioactive materials outside them. Based above background, the relationship between the quantity of soot loading onto the HEPA filter and the differential pressure (P) across the one was investigated. The tests with burning of major GB panels materials were performed using the large test apparatus (ACUA, Apparatus for Evaluating Clogging Effect of HEPA Filter on Confinement Capability Under Fire Accident), which enables to burn GB panels materials used as the GBs components in the actual facilities. The rising behavior of P has been evaluated with the increase of loading mass of soot, however, the relationship between loading volume of soot and P was newly examined in this study because the loading volume would be more appropriate than the loading mass as the index for expressing the progress of HEPA filter's clogging by soot loading. As a result, it was found that the rising behavior of P with soot loading in the relatively low region of loading volume could be uniformly represented regardless of combustion conditions such as the kind of GB panels materials and the ventilation in the cell for burning the material.