Tohoku Electric Power Co.’s Onagawa Nuclear Power Plant Unit 2 (Miyagi Prefecture) restarted on the 29th for the first time in 13 years. Japan’s nuclear power plant operation continued to be unevenly concentrated in western Japan, and the power supply remained chronically tight, especially in the Tokyo metropolitan area. The background to this is that reactors of the same type as Tokyo Electric Power Company’s Fukushima Daiichi Nuclear Power Plant are concentrated in eastern Japan, leading to lengthy safety reviews and difficulties in obtaining consent from local governments. The effects of the nuclear power plant accident are still felt strongly, and there is still a long way to go before “nuclear power normalization” can be achieved.
No difference in safety
Japan’s nuclear power plants use a type of reactor called a “light water reactor” developed in the United States. There are two types of furnaces, boiling water type (BWR) and pressurized water type (PWR), depending on the mechanism for generating steam, and each is developed by a different manufacturer. BWR is used by TEPCO, Tohoku Electric Power, Chubu Electric Power, and others, while PWR is used by Kansai Electric Power, Kyushu, Shikoku, and Hokkaido Electric Power.
In response to the Fukushima Daiichi Nuclear Power Plant accident, new regulatory standards established by the Nuclear Regulation Authority require that BWRs of the same type as Fukushima Daiichi be equipped with filter vents, an exhaust system that absorbs radioactive materials and prevents them from dispersing in the event of a serious accident. Maintenance became a condition for restarting operations.
As a result, electric power companies that own BWRs were forced to respond. The application for a safety review to the regulatory commission was also delayed, and the PWR review took precedence. A regulatory authority official said, “There is no difference in safety between the two reactor types, but it cannot be denied that BWR examinations have become stricter due to the impact of the Fukushima accident.”
Japan’s special circumstances
The 33 nuclear power plants in Japan are roughly evenly split between BWR and PWR, but according to research by the Japan Atomic Energy Industry Association, of the 433 nuclear power plants in operation around the world, BWR makes up about 14%. PWR is the highest at approximately 71%, making it the mainstream in the world.
A representative from the association pointed out, “The selection of reactor types depends on the circumstances of each country, but PWR, which was standardized in the 1970s, was adopted by advanced nuclear power countries.” Regarding the reason why Japan has a high proportion of BWRs, he says, “Japan is a rare country in the world where there are three plant manufacturers, but this is largely due to the fact that each company gradually domesticated the imported technology and decided to adopt the furnace type.” Analyze.
More than 13 years have passed since the Fukushima Daiichi nuclear power plant accident. The world’s nuclear power policy has entered a turning point due to the expansion of electricity demand due to the spread of generative AI (artificial intelligence). Nuclear power plants, which enable decarbonization and a stable supply of electricity, are essential when considering energy strategies for resource-poor Japan.
Chief Cabinet Secretary Yoshimasa Hayashi stated at a press conference on the 29th, “The importance of restarting operations is increasing from the perspective of Japan’s overall economic growth.” In that sense, the first restart of BWR can be said to be a major milestone.
In the future, the focus will be on how to resolve the structural issues that create regional differences in the operation of nuclear power plants in the east and west. It is natural for the government to take the lead in supporting the restart of nuclear power plants, but electric power companies are also required to make further efforts to restore trust in nuclear power plants. (Kenta Shiraiwa)
Onagawa nuclear power plant No. 2 restarts, thermal fuel costs reduced by 60 billion yen per year
Source: Japanese