Japan Chooses Light Water Reactors (LWRs) for Power Generation

In the early 1960s, Japan decided to experiment with different reactor designs before deciding which reactor type would be the best for Japan. JAERI, one of the STA R&D institutions, sponsored construction of Japan’s first nuclear reactor in 1963, which was a 12.5 MWe boiling water reactor designed by GE. Named the Japan Power Demonstration Reactor (JPDR), it was commissioned on 26 October 1963—the day was named “Nuclear Power Day” to commemorate

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the event. The JPDR was a major success and helped prepare Japan for the introduction of commercial nuclear reactors, according to JAERI researchers (Tanaka, et al., 1999).

 Over its lifetime the JPDR operated for a total of 17,000 hours and produced about 140 GWh of electricity. It shut down in 1976 due to problems with cracks in monitor tubes and failure of a control rod drive mechanism (Tanaka, et al., 1997).

Following the JPDR, Japan’s utility companies established the Japan Atomic Power Company (JAPC) to build two commercial nuclear reactors. The first was a 12 MW graphite-moderated, gas-cooled reactor designed by GE in the UK, which was called Magnox. The Magnox reactor was originally designed and built for the dual purpose of producing electrical power and plutonium 239 for the nuclear weapons program in Britain. The Japanese version of the reactor, called Tokai, began operations in July 1966 and was shut down in March 1998. The design suffered from modest generation capacity and low efficiency and so the utility companies judged it to be less than

satisfactory (Japan Atomic Power Company (JAPC), 2018).

JAPC’s second reactor was Tsuruga 1, a 357 MW BWR, designed by GE. Commissioned in 1969, the reactor was much liked and became Japan’s most popular nuclear reactor type. Of the total of 54 nuclear reactors that were in operation in Japan on 11 March 2011 (the date of the Fukushima Daiichi Nuclear disaster), 30 were BWR types and 24 were PWRs (JAPC, 2018; Japan Atomic Industrial Forum (JAIF), 2014).

While Tsuruga 1 was a great success, it also suffered from haphazard safety practices and maintenance problems. For example,

 On 24 October 1997, Tsuruga 1 had a malfunction of a control rod and the operation of the reactor was manually halted. The operators claimed that the failure of the control rod was due to a manufacturing error. The incident was rated an INES level 1 (Shippai Gakkai, 1997).

 On 21 July 2010, JAPC announced that it had never conducted inspections of the welded sections of reactor parts, such as the reactor circulation pumps and drainage valves from the reactor pressure vessel (JAPC, 2010).

 On 24 January 2011, METI’s NISA discovered that Tsuruga 1 had operated for about one month while one of the reactor’s multiple emergency cooling systems was malfunctioning.

NISA reprimanded JAPC for the safety violation. (Titibu, 2015).

Tsuruga 1 was scheduled to be decommissioned in December 2009 at the end of its 40-year design life but was granted permission in August 2009 to operate until 2016. While it was undergoing renovation and upgrading, the Fukushima nuclear disaster happened, which led to the establishment of more stringent safety regulations. Under the new regulations, JAPC could apply to extend the life of Tsuruga 1 to 60 years, but the owners decided to decommission it instead.

After the operation of three different reactors (JPDR, Tokai and Tsuruga 1) by the

semi-governmental R&D institution JAERI and the industry consortium JAPC, the Japanese utilities decided to begin the rapid expansion of nuclear power reactor fleet. KEPCO started first. It selected the PWR designed by Westinghouse for its Mihama power plant (See Table 4.1). Westinghouse had a long-standing licensing agreement with MHI and MHI had already received power

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generation and nuclear power technologies from Westinghouse, including the design and

manufacture of combustion turbines and nuclear steam supply systems (MHI, 2012). Thus, MHI served as a lead subcontractor for Westinghouse on the nuclear reactor project, called Mihama 1.

MHI’s learning curve was steep; according to Yoshioka (2013), the domestic content of the Mihama plant was initially about 62 percent and eventually increased to 99 percent after MHI became the prime contractor under a licensing agreement.

Table 4.1 Summary of the Mihama Nuclear Plant Reactor

Unit

Type Year Commis- sioned

Generation Capacity (MW)

Prime Contractor

Construction Cost

($ Million)

Domestic Content (%) Mihama

1

PWR 1970 340 WH MHI 312 62

2 PWR 1972 500 MHI 363

3 PWR 1976 826 Mitsubishi

Corporation

786 99

Source: Wikipedia, 2018a.

Just months after KEPCO started construction of Mihama, TEPCO launched its own nuclear power plant project, which was ironically the Fukushima Daiichi Nuclear Plant. TEPCO chose BWRs for the plant and contracted with GE for all the major components of the first reactor (See Table 4.2).

Toshiba and Hitachi served as subcontractors to GE for the project. Construction of Unit 1 started in 1967 and it was successfully commissioned in 1971.

 TEPCO continued to build five more reactors at the Fukushima Daiichi Plant during the 1970s. According to the company’s Fukushima Daiichi construction records, Toshiba and Hitachi had licensed the technology from GE, learned the tradecraft fast and served as contractors for all three major components of the first reactor Unit 1, including the reactor vessel, the turbine generator and the auxiliary equipment. As a result, the domestic content of the plant rapidly increased with each project. The domestic content of Fukushima Daiichi Unit 1 was initially about 56 percent and eventually became more than 99 percent

(Yoshioka, 2013).

 The Fukushima Daiichi Nuclear Power Plant undoubtedly was a major milestone in Japan’s nuclear history. The plant became a 6-reactor plant with a combined power generation capacity of 4.7 GW, one of the 15 largest nuclear reactor complexes in the world (Wikipedia, 2018b, 2018c). TEPCO was planning to construct Reactor 7 and 8 at the Fukushima Daiichi but cancelled the plan in May 2011 (Tokyo Electric Power Company (TEPCO), 2011).

 Fukushima Daiichi Unit 6 was a BWR with a different type of containment vessel and larger generation capacity. In this case, GE took the lead in building the reactor and turbine generator while Toshiba worked on the auxiliary equipment. Relying on foreign companies as the prime contractor was more the exception than the rule, however. (Yoshioka, 2013)

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By the end of the 1970s, the Japanese companies, Toshiba, Hitachi and MHI, had largely mastered all nuclear power plant component technologies. Today, they export to other east Asian countries under licensing agreements and are involved in the development of new reactor designs on a global basis. After the early plant construction projects by KEPCO and TEPCO, all the other Japanese electric utilities started to launch their own nuclear power plants. These fell into two groups in terms of the reactor type and the contractors. METI probably influenced this de facto division of labor to have a competitive, healthy industrial base for nuclear technologies (See Table 4.3) (WNA, 2018b).

Table 4.2 Summary of the Fukushima Daiichi Nuclear Plant Reactor

Unit Number

Type Year of Commis- sioning

Capacity (MW)

Prime Contractor Construc- tion Cost

$ Million

*

Domestic Content Reactor Turbine (%)

Generat or

Auxiliary Equip- ment Fukushima

Daiichi 1

BWR 1971 460 GE GE GE 390 56

2 BWR 1974 784 GE GE Toshiba 560 **

3 BWR 1976 784 Toshiba Toshiba Toshiba 620 **

4 BWR 1978 784 Hitachi Hitachi Hitachi 800 **

5 BWR 1978 784 Toshiba Toshiba Toshiba 900 99

6 BWR 1979 1,100 GE GE Toshiba 1750 **

* The original document shows the construction cost in Japanese yen. It is converted to US dollar at an exchange rate of 100 yen to a dollar. ** Unspecified.

Source: Denryoku Shimpo, 1979; Wikipedia, 2016

128 Table 4.3 Two Japanese Nuclear Industry Groups

Type of Reactor Boiling Water Reactor (BWR) Pressurized Water Reactor (PWR) Industry Group The Tokyo Electric Power

Company

(TEPCO)-Toshiba/Hitachi-General Electric (GE) Group

The Kansai Electric Power Company (KEPCO)-MHI-Westinghouse (WH) Group

Electric Power Companies

Tohoku Electric Power Company Chubu Electric Power Company Hokuriku Electric Power

Company

Chugoku Electric Power Company

Hokkaido Electric Power Company Shikoku Electric Power Company Kyushu Electric Power Company

Table was created by the authors.