{"id":3910,"date":"2017-08-04T11:43:38","date_gmt":"2017-08-04T02:43:38","guid":{"rendered":"http:\/\/www.cnic.jp\/english\/?p=3910"},"modified":"2017-08-04T13:05:05","modified_gmt":"2017-08-04T04:05:05","slug":"disturbing-plutonium-exposure-accident","status":"publish","type":"post","link":"https:\/\/cnic.jp\/english\/?p=3910","title":{"rendered":"Disturbing Plutonium Exposure Accident"},"content":{"rendered":"

\"\u5927\u6d17Pu_\u71c3\u6599\u8a66\u9a13\u68df_\u5927\u6d17\u7814\u7a76\u958b\u767a\u30bb\u30f3\u30bf\u30fc\u65bd\u8a2d\u914d\u7f6e\u56f3_fig1<\/a>Plutonium Dust Release at Japan Atomic Energy Agency\u2019s Oarai Research and Development Center\u00a0 Fuel Research Building<\/em><\/p>\n

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\u2019s (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 \u201cfelt wind pressure on his stomach.\u201d The five persons, who were wearing half-face masks to carry out the task, inspected themselves with an \u03b1 radiation surface contamination detector, confirming that they had all been contaminated.
\u00a0 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\u2019s \u201creport\u201d about a month after the accident.<\/div>\n
\u00a0<\/div>\n
Occurrence of the plutonium dust release<\/strong>
Table 1 shows a timeline of the events based on releases by the JAEA, NRA and news media.
\u00a0 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 \u201c(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).\u201d
\u00a0 As a result of a nasal smear (to detect contamination in the nostrils) taken inside the greenhouse, contamination of a maximum of 24 Bq (\u03b1 radiation) was detected in the nostrils of three of the five personnel.
\u00a0 The five task personnel finally exited the controlled area at 18:55. Since \u03b1 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. If plutonium were to be detected, it would have to be around 10,000 Bq or more. The task personnel were men in their 20s to 50s, two of whom were JAEA personnel, one was a dispatched staffer, and two were subcontracted company personnel. The person in whom 24 Bq of contamination was detected by nasal smear was a JAEA staff member and the main person carrying out the task.<\/div>\n
\u00a0<\/div>\n