Unit 2 of Japanese nuclear power plant Tokai, located in the Naka District, is one step closer to reopening following the successful completion of revised safety screening tests conducted by the country’s Nuclear Regulation Authority (NRA).
The plant, a 1,060MWe boiling water reactor owned by Japan Atomic Power Company (JAPC), is one of the oldest reactors in Japan, with the first unit built in the 1960s and commercial operation beginning in 1978.
JAPC first submitted its application for Tokai’s reopening in May 2014. While the NRA’s approval of the plant’s safety is a major milestone in the licensing process, several steps remain before JAPC can hope to restart operations.
First, NRA approval is needed for the extension of Tokai 2’s operating life, required in the areas of safety, detailed design and extension of operations. JAPC applied to the NRA for this in November 2017, hoping for the reactor to gain an extension of 20 years. The NRA’s response is expected in November of this year.
JAPC also needs to complete the installation of new safety measures at the site. The firm has estimated that around $1.6bn is needed for these additional measures, intended to protect against a potential tsunami which could reach a height of 17.1m. Construction of these components is due to be completed by March 2021, with the company indicating that the plant will not restart before this time.
Approval from local municipalities is also required prior to the site’s reopening.
Tokai 2 lost external power in March 2011 due to an earthquake, an event which also caused an accident at the Fukushima Daiichi plant. One of Tokai 2’s three emergency generators sustained damage from a subsequent 5.4m tsunami, though the plant was able to safely enter cold shutdown.
NRA approval is needed for a number of steps in cases of reactor restart requests. These include changes to reactor installation, approval of construction plans and safety inspections to assess whether the unit meets safety standards.
Plant operators are also required to add safety-enhancing equipment within five years of receiving NRA approval of a reactor’s engineering work programme.
The body has recently introduced new safety requirements, under which state reactors will have a nominal lifespan of 40 years with extensions granted only once and limited to a maximum of 20 years, depending on exacting safety requirements. Thus far, only three pressurised water reactors have received approval for extension under the new regulations; Takahama units 1 and 2, and Mihama 3. All are owned and operated by Kansai Electric Power Company.
Of the country’s 39 total operable reactors, nine have passed safety screening tests and resumed operation. These are Kyushu’s Sendai units 1 and 2, Genkai units 3 and 4, Shikoku’s Ikata unit 3, Kansai’s Takahama units 3 and 4 and Ohi units 3 and 4. A further 16 reactors have applied for reopening.