Report on contamination incident and restoration activity in the controlled area of Plutonium Fuel Fabrication Facility

Plutonium Fuel Development Center

The contamination incident in an operation room (Room No. A-103) of Plutonium Fuel Fabrication Facility (PFFF) in Japan Atomic Energy Agency (JAEA), Nuclear Fuel Cycle Engineering Laboratory occurred on January 30, 2019 during replacement of the double plastic bags which enclose a storage container containing nuclear material. At this time, some of nuclear materials spread all over the room. Nine workers in the room were contaminated with plutonium, but internal exposure of them was not confirmed. In order to restore the Room No. A-103 of PFFF, the Restoration Activity Team organized in JAEA carried out the decontamination work after the investigation of the contamination level in the room. The team had decontaminated the surface of walls, ceiling, gloveboxes and other instruments. Suitable decontamination methods were selected depending on the contamination distribution and installation state of the instruments. In addition to the manual wiping using wet wipes, the exfoliation method using a microfiber mop was applied for narrowed areas. As a result, the loose alpha-contamination level throughout the room fell below the detection limit. On other hand, the fixed alpha-contaminations were confined by painting after the decontamination. This report shown detail restoration activities for this time incident. This information is useful for making a manual on restoration activities and performing practice for the largescale contamination incident. We hope this report will be used for other facilities handled alpha-radioactive materials such as plutonium.