The facility handled plutonium but was unaware that a major accident could happen.
As the facts surrounding the June 6 incident where five workers were exposed to radioactive materials following an accident at a nuclear research facility in Ibaraki Prefecture continue to emerge, it has become clear that the facility’s stance concerning safety management has been simply too soft — especially considering that it handles materials used for nuclear fuel.
The accident in question happened at around 11:15 a.m. on June 6 at the Japan Atomic Energy Agency (JAEA)’s Oarai Research & Development Center in the coastal town of Oarai in Ibaraki Prefecture. Uranium oxide and plutonium oxide powder that had been stored in double-wrapped plastic bags inside a sealed stainless steel container were accidentally released across the research laboratory after the bags suddenly burst, thereby exposing all five workers nearby to the radioactive compounds. Prior to the leak, one of the workers — a man in his 50s — was opening the container for inspection.
The check was carried out at an unsealed work station referred to as the “hood.” The radioactive materials had been stored at a pressure level lower than the surrounding area, in an attempt to prevent them from leaking. However, this proved to be ineffective. The compounds flew across the room, in powder form, immediately after the bags burst open.
In addition to the hood, there is also a “glove box” inside the facility, which can be used to handle dangerous materials. However, the facility has no specific rules determining which work station should be used for which purpose, and it has become normal practice at the site for workers to handle sealed nuclear materials — such as those kept inside containers — at the hood work station.
Apparently, during the check of the stainless steel container at the Oarai facility, there was no intention of opening the plastic bags, and therefore, it was judged that, “There was no danger of being exposed to radiation.”
However, the contents of the stainless steel container had not been checked once in 26 years. Commenting on this issue, an executive from the Nuclear Regulation Authority (NRA) has criticized the JAEA, stating, “How could they even be sure that the contents were kept sealed?” Meanwhile, an executive from the JAEA has said, “It was not anticipated that the plastic bags would burst. It seems that working at the hood work station may have been inappropriate.”
In addition, it has become clear that the five workers were not wearing full-face masks at the time of the accident. Instead, they were wearing masks that only covered their noses and mouths. Also, despite the fact there was a surveillance camera in the room, no footage was recorded, and no one was video monitoring the situation at the time of the accident.
Furthermore, an official from the NRA points out that, “It seems the facility was unaware that a major accident could happen.”