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Event Report Forms (ERFs) are filed to the IAEA. Sometimes there are multiple event reports, updating the rating, the event description. Here you only see the latest event report

ERF send date: Fri, 01-10-1999
ERF description: Time: About 10:35 a.m., Thursday, September 30, 1999. Place: Conversion Test Building, JCO, Ltd.
An area radiation monitor was activated at the Conversion Test Building of the JCO Co., Ltd. Three workers were exposed to radiation and were taken to National Institute of Radiological Science. Two of them seriously. Details are being investigated.
The cause is now under investigation. It is fact that it occurred during transfer of low enriched uranium in nitric acid. A maximum dose of 084 mSv/h was recognised at the boundary of the site. A maximum dose rate (neutron) of 4.0 mSv/hr was recognised at the boundary of the site. STA's Action & Strategy: the evacuation was to 350 m. Most of the cooling water has been drained from the jacket. After that the dose rate of neutron decreased at the boundary of the site. Boron injection into the container is being considered now.
Justification of Rating:
Provisionally rated at INES level 4 based on on-site and off-site impact.
ERF rating date: 01-10-1999
ERF contact person: Akira Honda
ERF address: 2-1-1 Kasumigaseki, Chiyoda-ku, Tokyo 100, Japan
ERF affiliation: Office of International Relations, Nuclear Safety Bureau, Science and Technology Agency

This map shows a selection of reports from nuclear and radiological incidents stored in the IAEA NEWS-database.
Locations are estimates. Contact us if a location is wrong.
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Power Reactor Research Reactor Radwaste Facility Enrichment Facility Radiation Source Irradiation/Accelerator Facility Transportation

Fuel Fabrication Fuel Reprocessing Research Facility Mining/Milling Radioisotope Processing/Handling Facility Other