Comparative study of Japan and UK regulations on surface contamination density

Tsujimura, Norio   

The surface density limits currently set by Japan's regulations for radioactive surface contamination, 4 Bq/cm for -emitting radionuclides and 40 Bq/cm for /-emitting radionuclides, are based on the derived working limits studied by Dunster of the UKAEA in the 1950s and 1960s. This derived working limit was introduced into Japan's and the UK's legislation at about the same time. Since then, however, the regulatory content in Japan has remained almost unchanged, while in the UK it has been amended several times over the past few decades. The most recent UK legislation does not include specific numerical requirements for surface contamination density; therefore, nuclear operators are now taking voluntary measures such as setting their radiological control standards for surface contamination. This report provides primary reference material for discussing Japan's future regulatory framework for surface contamination density, including the historical evolution of the differences between Japan's and the UK's regulations.