JCO criticality accident termination operation

Kanamori, Masashi

JNC TN8440 2001-018, 50 Pages, 2001/12

JNC-TN8440-2001-018.pdf:1.31MB

On September 30 at around 10:35 AM, criticality accident occurred at the JCO's conversion building in Tokai-mura. Since criticality accident had not been anticipated, neither devices for termination of criticality accident nor neutron detectors were available. Immediately after the information of the accident, our emergency staff (Japan Nuclear cycle development institute staff) went to JCO site, to measure the intensity of neutrons and gammas. There were four main tasks, first one was to measure the radiation intensity, second one was to terminate the criticality accident, third one is to alert the residents surrounding the JCO site, fourth one is to evacuate the employees in the site. These tasks were successfully performed until October 1. This paper describes about how these operations were performed by the relevant staffs.

Improvement of the decontamination detergents and methods for body radioactive contamination, 2; Evaluation of residual locations after decontamination and spread of contamination by dequiping of protective equipments

Fujisawa, Makoto; Tomioka, Akifumi; Izaki, Kenji; Shioya, Satoshi

no journal, , 

It is important to predict the spread of radioactive materials attached to workers' bodies. We evaluated the degree to which contamination remained after wiping off protective gear and the degree to which contamination was dispersed when it was removed. In the test, we applied fluorescent paint that simulates radioactive substances to protective gear, wiped it off with a wet rag, and removed the gear. And we photographed the fluorescent paint with a camera and evaluated the decontamination effect of wiping and the spread of simulated contamination. As a result of the test, we were able to evaluate the degree to which the protective gear was contaminated.