Last Friday, the mayor of Suttsu, Hokkaido, a small town on the west coast of the island, applied for a preliminary survey for a final disposal site for high-level nuclear waste.

The survey is the first stage in the process of creating an underground storage facility for high-level radioactive waste from the nation’s nuclear power plants. In addition to Suttsu, the village assembly of Kamoenai, about 40 kilometers away, has also agreed to undergo a survey, which comes with substantial central government funding for the cash-strapped, graying localities.

What is a final disposal site for nuclear waste?

The reprocessing of spent nuclear fuel from the nation’s nuclear power plants produces highly radioactive waste, especially uranium and plutonium, that must be converted into a form of glass in a process called vitrification, placed inside stainless steel canisters and then into a cooling pool for a number of years, until the waste can be transferred to an underground final depository site.

There, the plan is for it to remain for anywhere between 1,000 and 100,000 years, until radiation levels decrease to a level that allows for safe handling.

The quasi-governmental Nuclear Waste Management Organization (NUMO) was established in 2000 to select a location and build the facility. Plans call for construction of a storage area at least 300 meters underground, covering an area of between six and 10 square kilometers, with between one and two square kilometers of surface facilities. The total cost of technology development, surveys, land acquisition, construction, operations and management is estimated at ¥3.9 trillion.

What is the current situation regarding Japan’s high-level nuclear waste?

As of March 31, according to NUMO, the total volume of spent fuel produced so far was equivalent to around 26,000 canisters of vitrified waste. But Japan is only storing 2,492 canisters, with the remainder in France and the U.K.

Most of the waste (2,176 canisters worth) is being stored near the village of Rokkasho, Aomori Prefecture, with 316 canisters near the village of Tokai, Ibaraki Prefecture. All 26,000 canisters will eventually have to be transported somewhere in Japan for final disposal.

Rokkasho has been storing waste for 25 years, after originally agreeing, in 1995, that it would temporarily store waste for up to 50 years before that waste would have to be moved to a final disposal site.

What are the basic conditions for choosing a final disposal site?

In 2017, the government released a color-coded map of the Japanese archipelago called the Geoscientific Characteristics Map, to show which parts of Japan were judged, at the time, favorable or unfavorable based on several conditions for building a permanent disposal facility.

These included the degree of risk from seismic or volcanic activity and ease of transportation access, especially by ship.

Yellow areas were judged as unfavorable in terms of the stability of geological conditions deep underground. Gray areas were those judged unfavorable due to the possibility of mineral excavation.

Light green areas were those seen as having favorable geological characteristics. Dark green areas, which included virtually the entire coastline areas of Hokkaido, Honshu, Shikoku, Kyushu and some Okinawan islands, were also favorable in terms of transportation convenience.

The Tokyo area was gray colored, indicating that it was judged unfavorable in terms of geoscientific characteristics due to the fact it contains natural gas.

Suttsu, with a population of about 2,900, was judged to be in a favorable area. Kamoenai, a village of 820, is about 40 kilometers to the north and not far from Hokkaido Electric Power Co.’s Tomari nuclear power plant. A portion of the town was judged to be favorable due to underground geological conditions.

What is the process and timeline for site selection and construction?

There is a three-stage process. In the first stage, for which Suttsu has applied, experts review historical records and data regarding the geological structure, including soil properties as well as groundwater flow and volcanic and seismic histories of the area. This stage is expected to take two years.

If a candidate site passes Stage 1, it moves on to the Stage 2 survey, which includes excavations to determine the geological foundation’s stability and to ensure groundwater will not leak into the underground facility. This stage is expected to take four years. Finally, Stage 3 involves analyzing the extracted strata to determine whether it would be safe to build an underground facility. That’s a process expected to take up to 14 years.

At the end of Stage 3, a decision on whether to formally choose the site would be made by the central government. If approved construction of facilities could begin, and the facility would be expected to begin operations 10 years after that. Assuming there were no unexpected delays, the entire process would take at least 30 years.

Why did Suttsu and Kamoenai apply?

Due to their graying populations both localities are strapped for cash.

By applying to undergo Stage 1, the preliminary data survey, Suttsu and, if the central government agrees, Kamoenai, can receive up to ¥2 billion in assistance from the central government over the two-year period.

If they are approved for a Stage 2 survey, which involves direct boring into the ground, they can receive another ¥7 billion over four years, regardless of whether or not they proceed to the Stage 3 analysis.

In Suttsu, the decision to apply was made by town head Haruo Kataoka, a five-term leader who ran unopposed in 2017 but faces re-election next year. His decision has angered many town residents and others in the surrounding region. Kataoka said that while he knows many residents are opposed, he also senses a large amount of support toward applying for the preliminary survey.

What are the political hurdles to actually building a disposal site in Hokkaido?

Hokkaido Gov. Naomichi Suzuki was also upset with Kataoka’s decision and, on Oct. 2, the Hokkaido Prefectural Assembly passed a unanimous resolution expressing concern with the way Suttsu acted.

In addition, the prefecture had already established an ordinance in 1995 saying that while it was necessary to conduct experimental research on ways of disposing nuclear waste, it would be difficult to actually accept such waste.

Hokkaido is the site of the Horonobe Underground Research Center, which conducts research and development on disposal methods for high-level radioactive waste.

A locality does not need the prefectural governor’s request to apply for the Stage 1 preliminary survey. But NUMO and the central government are expected to consult with any governor before proceeding to the next stages. Formal opposition at that point by a governor could delay or derail project plans.

Do other countries that use nuclear power have final disposal sites?

No country has actually built a final disposal site, although Finland and Sweden have selected locations for construction and Finland is expected to start construction in the early 2020s.

France is still conducting underground surveys, while Switzerland, China and Canada are analyzing boring samples. Belgium and Germany are at roughly the same stage as Japan.

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