Japan maps potential repository areas

A "scientific characteristic map" for the geological disposal of high-level radioactive waste has today been published by Japan's Ministry of Economy, Trade and Industry (METI). The map does not identify potential repository sites, but indicates areas that have suitable geological conditions to host such a facility.

A "scientific characteristic map" for the geological disposal of high-level radioactive waste has today been published by Japan's Ministry of Economy, Trade and Industry (METI). The map does not identify potential repository sites, but indicates areas that have suitable geological conditions to host such a facility.

In May 2015, after a review of existing policies, Japan adopted a new basic policy on the final disposal of high-level waste. This included the decision to present the scientific characteristics of the entire country in order to promote initiatives under the premise that development of a repository is the responsibility of the present generation. Having such information would also help gain the understanding and cooperation of the population and the regions.

Areas shaded orange and grey are considered unsuitable for a repository. Pale green areas are considered of potential, while dark green coastal areas are preferable (Image: METI)

Based on two calls for public comment in August 2016 and March 2017, as well as other information, the Geological Disposal Working Group under METI's Advisory Committee for Natural Resources and Energy presented a report in April titled Summary of Requirements and Criteria for a Nationwide Map of Scientific Features for Geological Disposal.

METI has produced a scientific characteristic map based on these identified requirements and criteria. The map, it says, identifies regions that are likely to meet the necessary geological requirements for hosting a repository and could be included in a future detailed site selection survey. The map was published today on the website of Japan's Nuclear Waste Management Organization (NUMO).

In order to determine whether a location is suitable for a repository, various scientific characteristics were taken into consideration, METI said. These include the influence of natural phenomena such as volcanic activity and fault activity, the strength of the underground rock, soil temperature and groundwater acidity. While much of this is already known from existing nationwide data, METI said detailed investigations would need to be conducted at specific sites.

The map shows areas not suitable for a repository due to their proximity to volcanoes or active faults. These areas are coloured orange on the map. Areas which have resources of coal, oil, natural gas, metals or minerals - coloured grey - are also excluded due to the potential of future drilling activities. Regions which are considered to have relatively high potential for hosting a repository are coloured pale green. Coastal areas within these regions are coloured dark green. METI said locations on the "green coast" are considered to be preferable in terms of transportation.

METI noted the map does not "definitively indicate whether each region has suitable scientific characteristics for a disposal site". It is necessary to conduct "a three-step survey based on the law, including elements not included in the scientific characteristic map", it said.

Akio Takahashi, president of the Japan Atomic Industry Forum, said: "The presentation of the map is the first step on a long road leading to the realisation of geological disposal, but this does not determine the disposal location, and a detailed disposal site selection survey is required to select a location."

NUMO expects site selection from about 2025, with repository operation from about 2035, and the ¥3500 billion ($31 billion) cost of it will be met by funds accumulated at 0.2 yen/kWh from electricity utilities and paid to NUMO. By 2015, ¥1000 billion had been collected thus. This sum excludes any financial compensation paid by the government to local communities.

Researched and written
by World Nuclear News