At the meeting, representatives of the Nuclear Waste Management Organization of Japan (NUMO) explained a draft report on literature survey—conducted for Suttsu Town and Kamoenai Village, both in Hokkaido—toward the selection of an HLW disposal site. They showed that both municipalities would be candidate sites for preliminary investigations following those literature surveys.
A literature survey is the first process in a three-phase investigation, as follows:
- literature survey (ca. 2 years)
- preliminary investigation (ca. 4 years)
- detailed investigation (ca. 14 years)
The investigation is being conducted toward the selection of a disposal site as provided for in Japan’s Designated Radioactive Waste Final Disposal Act. A literature survey is primarily an academic investigation of regional literature and data, such as geological maps and mineral resources maps. Proceeding to the next phase—preliminary investigations—requires agreement from the governor of Hokkaido and the heads of the two municipalities.
In October 2020, NUMO accepted applications for investigations from Suttsu Town and Kamoenai Village, and started the literature surveys the following month. Since April 2021, NUMO has conducted dialogues with local residents as part of its efforts to share and provide information. At the same time, as no municipalities other than those two had come forward to participate, the Cabinet, in April 2023, decided to revise the basic policy on final disposal to strengthen the government’s involvement and to promote the invitation of applications from other candidate sites.
At the start of the working group’s meeting on February 13, Director-General KUME Takashi of the Electricity and Gas Industry Department of the Agency of Natural Resources and Energy (ANRE) expressed again his gratitude to the two sites for their understanding on the challenge of geological disposal and their acceptance of the literature surveys. Saying that “the surveys in the two locations were the first in Japan, and will certainly serve as reference cases for future surveys in other places,” he said that the government would “proceed with processes from now on thoroughly and with careful consideration.”
Regarding the draft report on the literature surveys at the town and village, HYODO Hideaki, director of NUMO’s Science and Technology Department, talked about the overall process of evaluation, based on the Evaluation Guidelines for Literature Survey issued in the fall of 2023 by the Specified Radioactive Waste Subcommittee, the superior body to the working group.
He explained three issues: (1) the technical aspects of the evaluation results, including geological characteristics involving earthquakes, active faults and volcanoes, (2) whether or not mineral or geothermal resources were present, and (3) the points to be considered in carrying out a preliminary investigation from both economic and societal perspectives.
Mount Shakotan, in Shakotan Town and adjacent to Kamoenai Village, is a quaternary volcano (active most recently ca. 2,400,000-2,500,000 years ago). The village lies mostly within a 15km radius of the summit. A precise limit is not clear, but the area is labeled in the color-coded Map of Scientific Features as one where unfavorable features are expected. Thus, it is necessary to consider the question again, primarily gathering more information on conduits, the crater and the like. After consideration of those points, the entire area of Suttsu Town and the southern end (3-4km2) of Kamoenai Village will become candidates for preliminary investigations.
The working group will meet several times to develop a plan in accordance with the draft report and continue to address matters from various technical points of view.
Hokkaido Governor SUZUKI Naomichi, referring to the draft of the literature survey report that was released, expressed his objection to shifting to the phase of preliminary investigation. He released the following comment: “Through explanatory meetings, the circumstances in Hokkaido―including the fact that there is opposition to becoming a disposal site, something the draft report does not acknowledge―will be known nationally, thus increasing understanding of the final disposal project.”
