The primary objective of government policy, and of NUMO in implementing this policy, is to
ensure that a repository for Japan’s high-level radioactive waste is located so as to provide
secure isolation of the waste and adequate safety for present and future generations. This
means that the site has to be chosen carefully, taking full account of all its characteristics. In
order to address these characteristics in an orderly and structured manner, we have established
a comprehensive set of Siting Factors, which, together, help determine the suitability of any
potential repository site. At present, these Siting Factors have been developed only so far as is
necessary to address the first stage of our siting programme – the identification of Preliminary
Investigation Areas.
Japan lies in a region of active global tectonics – characterised by dynamic geological
processes, volcanism and earthquakes. One of the first things that we need to be sure about is
that a repository is not located where it could be adversely affected by these events and
processes over a long period of time in the future, which means that we need to take account
of tectonic mechanisms and how they change with time. The first application of the Siting
Factors addresses this issue.
