Part III. Preliminary surveillance of prospective site — environmental considerations —

Abstract

The environmental issues in the R-project are mainly considered from radiological safety point of view. Supposing a new experimental site for the program to be constructed in Toki Area, land and water surveys have been made since 1982 on the background radiation levels and radioactive material concentrations. Results of in-situ observations using instruments of various types are given and compared, such as TLD's (exposed for every three months), a pressurized ionization chamber, a NaI(Tl) detector in DBM mode, and a portable Ge detector. Also shown are the data from laboratory analyses of sampled materials in α- and γ-spectrometries, and neutron activation method. Tritium concentrations in river water samples have been quarterly measured with a liquid scintillation counter. These kinds of data will further be compiled to define the regional characteristics of the site environments. In relating to the expected radiation yields in the R-project, the importance of monitoring methods effective to pulsed radiation components is particularly emphasized. Possible use of ionization chamber and TLD's for this purpose is discussed in some detail with the preliminary application to the existing tokamak experiments on JIPP T-IIU.