JAPAN ATOMIC INDUSTRIAL FORUM, INC.

for Japanese

ATOMS in JAPAN

7 August, 2017

Draft of New Technical Strategy for Fukushima Daiichi Released, Showing Direction for Fuel Debris Removal

On July 31, at a meeting of the new Fukushima Council of the Committee on Decommissioning Measures, Japan's Nuclear Damage Compensation and Decommissioning Facilitation Corporation (NDF) presented its evaluation of measures for fuel debris removal for use in the decommissioning of the Fukushima Daiichi Nuclear Power Plants.

NDF President Hajimu Yamana proposed it as a new technical strategy plan to provide the technical basis necessary to realize the “mid-and-long-term roadmap” toward the NPPs’ decommissioning. The roadmap was originally issued by both the Japanese government and the Tokyo Electric Power Co. (TEPCO). The current version of plan—originally released in July 2016—will be revised soon based on the results of investigations of the interiors of the primary containment vessels (PCVs) and other locations at the Fukushima reactors.

Dr. Yamana began with the fundamental recognition that the decommissioning of Fukushima Daiichi was a project with great inherent uncertainty. Even in the face of that uncertainty, he said, the NDF would push ahead affirmatively and flexibly, while making use of past experiences and knowledge, and placing top priority on safety. He then enumerated several adjectives characterizing the effort, as follows: safe, certain, rational, prompt and practical on-site.

Concerning fuel debris, he described the conditions inside the pedestals (located below the reactor pressure vessels) at the bottoms of the PCVs at Units 1 to 3 at Fukushima Daiichi, comparing them with each other. He said that fuel debris existed mostly on the floor, though the amount was small, and that more fuel debris was on the floor than in Unit 2.

Yamana went on to talk about the evaluations of the feasibility of fuel debris removal measures. He said that although the conditions inside the reactors were not fully understood, it was possible to address removal possibilities using calculations and/or simulations of the reactor core meltdowns, as well as observations using muon measurement technology and other methods, while also estimating those interior reactor conditions that could be deemed most certain.

Accordingly, comprehensive evaluations were first made of measures taken up in the technical strategy plan released in 2016, namely: (1) water-covered, with removal of fuel debris from the upper part of the containment vessel (CV), (2) uncovered, with removal from the upper part of the CV, and (3) uncovered with removal from the side of the CV. The evaluations primarily focused on such aspects as water levels and access routes.

Based on the knowledge accumulated so far, as well as the time needed to reach the fuel debris, the conclusion was that it would be most practical to first remove the debris lying at the PCV bottom from the side of the CV.

In addition, Yamana stressed the importance of project management in the proposed new technical strategy plan, particularly on such matters as waste measures, R&D promotion, and strengthening international cooperation. He said that was because highly difficult activities in technical terms—such as the removal of fuel debris—will soon be in full swing.

Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.

SNS facebooktwitter

NPPs Map

Video

“The current situation at Fukushima Daiichi NPS” -From 3.11 toward the future- (ver, July 2019)

8 July, 2019
“The current situation at Fukushima Daiichi NPS” -From 3.11 toward the future- (ver, July 2019)09:17

Recent News

17 October, 2019
JAIF Holds Women’s Symposium, with Presentations by Weathercaster and Professor
7 October, 2019
Fukushima Joban Products Fair Begins, Featuring Seafood Sent Directly to Restaurants in Tokyo-Yokohama Area
3 October, 2019
Kindai University, Hayakawa Rubber Develop Easily-molded Radiation Shielding Material
30 September, 2019
MEXT Minister Shares His Hopes with the Press, Seeking to Secure Human Resources Together with Universities
19 September, 2019
Minister of State for Science and Technology Policy Attends Opening Ceremony of Japan Booth at IAEA General Conference
19 September, 2019
At 63rd IAEA General Conference, Japanese Minister of State for Science and Technology Policy Stresses Need for Science-based Discussions on Decommissioning and Contaminated Water Measures
10 September, 2019
Symposium in Tokyo Looks at Taiwanese Energy Situation, and Discusses Fear and Misinformation about Foods Sourced in Fukushima
10 September, 2019
Kyushu Electric Power Files Decommissioning Plan for Genkai-2 and Seeks Change to Genkai-1 Plan, with Work on Both to Proceed Simultaneously
4 September, 2019
White Paper on Nuclear Energy Features Decommissioning, Accumulation of Technology as “Great Assets” for the Future
29 August, 2019
TEPCO to Decide Fate of Kashiwazaki Kariwa Units 1 to 5 Five Years after Restarting Units 6 and 7
▲TOP