Report on cause investigation and countermeasure of leakage trace from the drum

On September 11, 2015, leaky traces of bituminized wastes were confirmed from four drums filled with bituminization in waste packages storage yard (II) of waste management facility in Oarai Research and Development Center (This place is the current Oarai Research and Development Institute). Moreover, even after the subsequent investigation, a leakage trace was found from one bituminous drum on November 10, 2015. Furthermore, on December 2, 2015, there was no a leakage trace in one bituminous drum, however the upper lid was found to be intensely corroded. To investigate the causes and the countermeasures for leakages of bituminized wastes from the drums, we have set up a Work Group to investigate the causes and the countermeasures to leakage traces from the drums. Specific considerations were (1) To ascertain the causes of leakages from the drums, (2) To ascertain the causes of corrosion (rust) on the drums, and (3) To prevent leakages and corrosion (rust) of the drums from recurrence. This report is based on investigative report summarized by this working group, the report was reconstructed including the contents clarified in the subsequent document investigation. (author)