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Japanese team achieves high-precision mass measurements of argon isotopes, revealing variations in the strength of the new magic number N=32

An international collaborative research team comprising RIKEN and the High Energy Accelerator Research Organization (KEK), among others, conducted high-precision mass measurements of short-lived argon isotopes far from the line of nuclear stability, using the superconducting RI beam generation and separation device BigRIPS at the RI Beam Factory (RIBF) of RIKEN Nishina Center for Accelerator-Based Science, as well as the CRISMASS system, a stationary slow radioactive isotope precision mass spectrometer jointly developed by the two institutions. The research team directly measured the mass of argon-50 (^50Ar, 18 protons, 32 neutrons) for the first time, and improved the mass measurement precision of argon-49 (^49Ar) by approximately 250-fold compared to previous measurements, providing insights into the energy of the two-neutron shell gap near the new magic number N=32. The results have been...

2026-08-31

Japan Plans to Include Hitachiomiya, Ibaraki Prefecture, in Nuclear Waste Disposal Site Selection Survey

According to sources familiar with the matter on August 31, Japan's Ministry of Economy, Trade and Industry is considering conducting a preliminary survey in Hitachiomiya, Ibaraki Prefecture, to designate the city as one of the potential candidate sites for a final disposal facility for high-level radioactive waste. The relevant plan is expected to be submitted to the Hitachiomiya municipal government. If the local government accepts the plan, Hitachiomiya will become the fifth location in Japan to undergo such a preliminary survey. The site selection process for Japan's high-level radioactive waste disposal facility involves multiple stages, and the entire screening process typically takes several years. The proposed preliminary survey is an early step to determine whether the area meets the conditions for further evaluation...

2026-08-31

Japan nuclear waste, geological disposal, literature survey, Hitachiomiya City

Japan's Ministry of Economy, Trade and Industry (METI) is in the final stages of coordination regarding the site selection process for the final disposal of high-level radioactive waste, with plans to request Hitachiomiya City in Ibaraki Prefecture to conduct a literature survey. The literature survey is the first phase of Japan's screening process for selecting a final disposal site for high-level radioactive waste generated from nuclear power generation. It primarily relies on existing literature and materials to assess whether candidate areas have safety concerns such as volcanoes and active faults. Hitachiomiya City is located in the northwestern part of Ibaraki Prefecture, bordering Tochigi Prefecture, with a population of slightly over 35,000. The city does not face the sea, with the Kuji River and Naka River flowing through its territory. Forests account for approximately 60% of the city's total area, and agriculture and manufacturing are the main industries. In recent years, the city has been promoting tourism and emerging industries leveraging the natural environment, while also facing challenges such as population decline, aging, and fiscal pressure.

2026-08-31

Decontaminated soil from Fukushima used in flower beds at Saitama municipal government building

Decontaminated soil generated after the Fukushima Daiichi Nuclear Power Station accident was transported on August 30 to a government building in Saitama City, Japan, and used in a reuse project for on-site flower beds. The work took place at the Saitama Shintoshin Joint Government Building in Chuo Ward, Saitama City. Approximately one cubic meter of decontaminated soil was brought to the site, where workers dug holes in the flower beds, filled the soil to a depth of about 20 centimeters, and then covered it with approximately 20 centimeters of ordinary soil. Similar decontaminated soil reuse work was carried out on August 29 at the Sendai Joint Government Building in Miyagi Prefecture. Apart from demonstration projects within Fukushima Prefecture, this is the second reuse case conducted outside the Tokyo area. On the day of the work, approximately...

2026-08-31

Japan to Establish New Decontamination Base in Okuma, Fukushima

Japan's Ministry of the Environment has decided to establish a new work base in Okuma Town, Fukushima Prefecture, in the next fiscal year to coordinate decontamination and house demolition work in difficult-to-return zones following the accident at Tokyo Electric Power Company (TEPCO)'s Fukushima Daiichi Nuclear Power Station, aiming to accelerate environmental recovery in the affected areas. Within seven municipalities surrounding the Fukushima Daiichi Nuclear Power Station, approximately 309 square kilometers have been designated as difficult-to-return zones. These areas remain under strict control, with restrictions on residential habitation and entry, and evacuation orders remain in effect. Within the difficult-to-return zones, the Japanese government has established "specified return residential areas" and plans to advance decontamination, house demolition, and other measures based on residents' intentions to return. The proposed new base in Okuma Town will be responsible for on-site management and project coordination, with approximately 30 staff members expected to be assigned, and the relevant branch office currently located in Hirono Town will be relocated to Okuma Town.

2026-08-30

Japanese Nuclear Regulator Inspects Horonobe Geological Disposal Research Facility for High-Level Radioactive Waste

On August 28, Shinya Nagasaki and other members of Japan's Nuclear Regulation Authority (NRA) inspected an underground research facility in Horonobe Town, Japan. The facility, operated by the Japan Atomic Energy Agency (JAEA), conducts technical research on deep geological disposal of high-level radioactive waste. Geological disposal of high-level radioactive waste involves encapsulating the waste and burying it deep underground, achieving long-term isolation through engineered and natural geological barriers. During the inspection, Nagasaki and his delegation examined test facilities used to evaluate the corrosion resistance of iron containers. The tests simulate the environment of containers holding heat-generating radioactive waste after being buried underground...

2026-08-30

Japan's Fukui Prefecture Approves KEPCO's Construction of Dry Cask Storage Facilities for Spent Fuel

Fukui Prefecture Governor Tatsuji Sugimoto announced on August 28 that he approved Kansai Electric Power Company's (KEPCO) plan to construct dry cask storage facilities for spent fuel within the premises of the Mihama and Takahama nuclear power plants in Fukui Prefecture. The decision was made in accordance with the safety agreement between Fukui Prefecture and KEPCO. KEPCO plans to apply to the Nuclear Regulation Authority (NRA) for approval of the relevant design and construction plans as early as August 31. KEPCO plans to build dry cask storage facilities at three nuclear power plants in Fukui Prefecture to temporarily store spent fuel and prepare for future transport to an interim storage facility outside Fukui Prefecture. Among these, the plans for the Mihama and Takahama nuclear power plants...

2026-08-29

Further Delay in Completion of Safety Measures at Japan's Tokai Daini Nuclear Power Plant

Japan Atomic Power Company (JAPC) announced on August 28 that the safety measure works required for the restart of the Tokai Daini Nuclear Power Plant in Tokai Village, Ibaraki Prefecture, are now expected to be completed between October 2028 and March 2029 (the second half of fiscal 2028), delayed from the original target of December 2026. This marks the fourth postponement of the completion schedule for the plant's safety measures. One of the key projects among the safety measures at Tokai Daini is the construction of a seawall approximately 17 meters high to protect against tsunamis. In June 2023, defects including incomplete concrete filling and deformed rebar were discovered in the seawall's foundation works, and related construction was subsequently suspended. JAPC has since applied to the Nuclear Regulation Authority (NRA)...

2026-08-29

Hole of about 3 meters confirmed at bottom of reactor pressure vessel of Unit 3 at Fukushima Daiichi Nuclear Power Station

Tokyo Electric Power Company (TEPCO) announced on August 27 that a hole approximately 3 meters in diameter has been confirmed at the bottom of the reactor pressure vessel of Unit 3 at the Fukushima Daiichi Nuclear Power Station. The pressure vessel is a steel container that held nuclear fuel before the accident, with a cylindrical shape and a diameter of about 5.5 meters. This is the first time since the core meltdown accident at Units 1 to 3 of the Fukushima Daiichi Nuclear Power Station in 2011 that the specific size and shape of such a hole have been confirmed on the pressure vessel. The hole is believed to be related to the falling of melted nuclear fuel during the 2011 accident. After the accident, the containment vessel of Unit 3 has maintained a relatively high water level for an extended period, and access routes into the containment vessel are limited. TEPCO previously used a micro drone measuring approximately 12 centimeters per side...

2026-08-28

Fukui Prefecture in Japan Aims to Promote Local Utilization of Nuclear Power

On the 27th, Fukui Prefecture in Japan held a co-creation meeting to exchange views on development measures for areas hosting nuclear power plants. The meeting confirmed a new policy aimed at promoting the local use of electricity generated by nuclear plants to drive related industrial development, including attracting large-scale data centers and other high-power-consuming businesses. Fukui Prefecture has held co-creation meetings for the past five consecutive years, with participants including the Fukui Prefectural Government, local governments in areas within the prefecture hosting nuclear plants, Japan's central government, and representatives of electric power companies. The meeting focused on how to combine the stable power supply and carbon-dioxide-free operation of nuclear plants with regional industrial revitalization...

2026-08-28

Japan Extends Deadline for Anti-Terrorism Facility Construction at Onagawa Nuclear Power Plant Unit 2

The Nuclear Regulation Authority (NRA) of Japan has officially decided to revise relevant regulations to extend the deadline for installing anti-terrorism facilities, specifically "facilities for responding to specified severe accidents," at nuclear power plants. Under the new rules, the deadline will be adjusted from "within five years after the construction plan is approved" to "within five years after the start of commercial operation." The revised regulations are expected to take effect in September. This change will affect Tohoku Electric Power's Onagawa Nuclear Power Plant Unit 2. The unit, which had faced the possibility of shutdown by December 2026 due to difficulties in completing the required facilities by then, will now be able to continue operating beyond that date. Tohoku Electric Power...

2026-08-28

Japan to Build Fusion Tritium Fuel Research Base in Aomori Prefecture

Japan's Ministry of Education, Culture, Sports, Science and Technology (MEXT) has decided to establish a new fusion power generation research base in Aomori Prefecture, focusing on tritium fuel handling technology. The base will target the development needs of fusion demonstration projects in the 2030s, promoting joint research and development among industry, government, and academia. MEXT plans to include approximately 100 billion yen in fusion development-related funding in its budget request for the next fiscal year. Fusion power generation releases energy through the fusion reaction of deuterium and tritium nuclei, a principle similar to the energy generation process inside the sun. Unlike traditional nuclear power that relies on nuclear fission chain reactions, fusion reactions carry a lower risk of runaway, leading many countries to view it as an important direction for future energy technology...

2026-08-28

Japan's Tokai No. 2 Nuclear Power Plant Seawall Reinforcement Plan Receives Basic Approval

Japan's Nuclear Regulation Authority (NRA) held a review meeting on the 27th local time and basically approved the seawall structural modification plan for the Tokai No. 2 Nuclear Power Plant submitted by Japan Atomic Power Company (JAPC). The plant is located in Tokai Village, Ibaraki Prefecture, Japan, and the relevant seawall is an important component of the safety measures required for restart, with foundation defects having been discovered during construction. According to JAPC's explanation, the modification plan does not remove the underground foundation where defects were found, but instead adds pile foundations around it and uses cement-based materials to reinforce the ground. Regarding this plan, JAPC submitted an assessment of the seawall's seismic and tsunami resistance performance after modification, concluding that the structurally adjusted seawall can still fulfill the functions required of a tsunami protection facility.

2026-08-28

Kansai Electric Power Revises Nuclear Emergency Disaster Prevention Business Plans for Three Nuclear Power Plants

Kansai Electric Power Co., Inc. announced on August 27 that it has revised the nuclear operator disaster prevention business plans for the Mihama, Takahama, and Oi nuclear power plants in accordance with Japan's Act on Special Measures Concerning Nuclear Emergency Preparedness, and filed them with the Prime Minister and the Nuclear Regulation Authority on the same day. The revisions pertain to nuclear emergency disaster prevention arrangements at the three nuclear power plants. Kansai Electric Power stated that it will continue to ensure the safety of the nuclear power plants and enhance nuclear emergency disaster prevention measures in accordance with the relevant plans. According to the documents, the consultation period prior to the revisions was from May 13 to July 30, 2026, totaling 79 days. The consultation parties included the local governments where the nuclear power plants are located and related neighboring local governments.

2026-08-27

Ikata Nuclear Power Station Unit 3 in Japan briefly deviated from operational limits due to abnormal signals in protection system instrumentation

Shikoku Electric Power Co. reported on August 27 that abnormal signals from safety protection system instrumentation appeared in the central control room of Ikata Nuclear Power Station Unit 3, which was in normal operation, indicating that one channel of the overtemperature ΔT related instrumentation was unreliable. The operator determined at 22:10 on August 26 that the unit had deviated from the operational limits stipulated in the Reactor Facility Security Regulations. On-site confirmation showed that the unreliable signal originated from 1 of the 4 channels of the overtemperature ΔT protection function. Overtemperature ΔT is one of the reactor automatic trip elements, used to protect in-core fuel; its limit value is calculated based on parameters such as reactor power, pressurizer pressure, and...

2026-08-27