The News That Matters about the Nuclear Industry

Japan: Disturbing Plutonium Exposure Accident

 Chihiro Kamisawa, Masako Sawai, CNIC  BY CNIC_ENGLISH · AUGUST 4, 2017 At around 11:15 on June 6, 2017, a plutonium release and exposure accident occurred in an analytical lab (Room 108, a controlled area) at Japan Atomic Energy Agency’s (JAEA) Research and Development Center Fuel Research Building. During work to inspect a storage canister (unopened in 26 years since 1991) containing plutonium and other nuclear fuel materials in laboratory fume hood H-1, the canister lid rose up after four of the six bolts were removed and the instant the remaining two bolts were removed the plastic bags inside the canister burst. The polyethylene container in which the nuclear fuel material was placed was double wrapped in two plastic bags. When these bags burst, the materials in the polyethylene container were abruptly released. The main person carrying out the task stated that he “felt wind pressure on his stomach.” The five persons, who were wearing half-face masks to carry out the task, inspected themselves with an α radiation surface contamination detector, confirming that they had all been contaminated.
While there are many unknowns regarding the accident and its cause, the exposure of the task personnel and other matters, we report here on what has become clear thus far and the problems that the accident poses. The Nuclear Regulation Authority (NRA) is scheduled to release the agency’s “report” about a month after the accident.
Occurrence of the plutonium dust release
Table 1 [on original] shows a timeline of the events based on releases by the JAEA, NRA and news media.
Several black lumps fell onto the floor in Room 108, from which a maximum of 55 Bq/cm2 were detected. The facility management supervisor instructed that a greenhouse (a temporary enclosure to implement detection and decontamination when retreating from the contaminated area) be set up at 11:54, and it is reported that this was completed at 14:29. More than three hours passed between the time of the accident and the time when the five task personnel exited the greenhouse. Concerning the delay in setting up the greenhouse, JAEA explained to NRA that “(The delay occurred because) the main work personnel in the Fuel Research Building were carrying out this work and other staff were engaged in stabilizing procedures for nuclear fuel materials (and could not leave their positions).”
As a result of a nasal smear (to detect contamination in the nostrils) taken inside the greenhouse, contamination of a maximum of 24 Bq (α radiation) was detected in the nostrils of three of the five personnel.
The five task personnel finally exited the controlled area at 18:55. Since α radiation had been detected in their nostrils and there was a strong possibility that the five people had inhaled plutonium, they were transported to the Nuclear Fuel Cycle Engineering Labs in Tokai Village, where measurement of plutonium inside their lungs was carried out using a lung monitor. Lung monitors detect the weak X-rays emitted by plutonium-239 and the gamma radiation emitted from americium-241 inside the lungs from outside the body. However, not only is this detection extremely difficult, it has poor sensitivity. The JAEA measurement results are shown in Table 2. [on original]………
This inappropriate long-term storage problem clearly shows, if one looks back at the historical series of organizations – the Nuclear Safety Commission, the Nuclear and Industrial Safety Agency and the NRA, that for 30 years or more none of these organizations made any public announcements on the issue, or knew what was happening and simply turned a blind eye. The regulatory organizations’ neglect thus far and the defensive awareness that they do not want this to be aired in public has undoubtedly been one of the remote causes of the accident at Oarai. This extremely facile method of dealing with plutonium and nuclear fuel materials is apparent from the notion that, since no serious accident has taken place up to now, it is fine to have the facility operators quickly sweep the problem under the carpet…….

October 16, 2017 - Posted by | incidents, Japan

No comments yet.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: