Radioactive noble gases in surface air monitored at MRI, Tsukuba, before and after the JCO accident

Monitoring results of radioactive noble gases after the JCO criticality accident, Tokai, Japan at the MRI, Tsukuba, about 60 km southwest of from the accident site, are presented. Although the experiments to detect radioactive noble gases from the JCO accident proved negative, the possible transport of a radioactive plume from the accident site is described based on the wind data obtained at two meteorological observation towers in Tokai and Tsukuba. Also, the maximum emissions of the noble gases from the accident are evaluated on the basis of the observations.