Restarts of reactors at the Ikata nuclear power plant in Ehime Prefecture will be delayed until at least next year because the site does not meet safety standards.
Restarts of reactors at the Ikata nuclear power plant in Ehime Prefecture will be delayed until at least next year because the site does not meet safety standards.
Its operator, Shikoku Electric Power Co., is being forced to construct a new emergency headquarters building at the facility as the current one, which was completed after the March 2011 Fukushima nuclear disaster, fails to meet the new criteria.
The new building is scheduled to be completed in January 2015 at the earliest. Given that procedures for safety screening take time, the utility said it was doubtful the reactors could be reactivated this fiscal year, which ends in March 2015.
Shikoku Electric is not the only electric power company that has been obliged to construct new emergency headquarters buildings in their nuclear power plants.
Such facilities are expected to serve as command centers in the event of a nuclear accident. Thus, the buildings are required to withstand strong earthquakes and serve as a shield against radiation under stringent safety standards imposed by the Nuclear Regulation Authority (NRA) in July 2013.
Before the introduction of the more vigorous standards, some electric power companies built quake-resistant emergency headquarters buildings based on lessons from the offshore Niigata Chuetsu-oki earthquake in 2007.
The earthquake rendered one of the rooms for emergencies in Tokyo Electric Power Co.’s Kashiwazaki-Kariwa nuclear power plant in Niigata Prefecture temporarily unusable.
Shikoku Electric, based in Takamatsu, constructed its emergency headquarters building at a cost of some 4 billion yen ($40 million).
The quake-proof building accommodates the emergency headquarters in the Ikata nuclear power plant and has a total floor space of about 600 square meters. It became operational in December 2011.
In the NRA’s screening to decide whether the Ikata plant is safe to resume operations, the assumed intensity of a future earthquake is likely to be raised. That will require strengthening parts of concrete pillars in the foundations of the emergency headquarters building.
Shikoku Electric decided it would be better to construct a new structure, one that will be one-story high and made of reinforced concrete. It will have a total floor space of about 200 square meters.
Construction is set to start in September and take five to six months to complete.
A number of other nuclear power plants are faced with a similar problem.
For example, the emergency headquarters building of Tohoku Electric Power Co.’s Onagawa nuclear power plant in Miyagi Prefecture was deemed to be insufficient to shield people from radiation under the new safety standards. The building was completed in October 2011.
The same problem applied to the building at Japan Atomic Power Co.’s Tokai No. 2 nuclear power plant in Ibaraki Prefecture, which was completed in March 2011.
The emergency headquarters building at Chubu Electric Power Co.’s Hamaoka nuclear power plant in Shizuoka Prefecture, which was completed in August 2010, was also deemed to be unable to withstand major earthquakes or shield workers from radiation.
Electric power companies that did not construct emergency headquarters buildings after the Niigata Chuetsu-oki earthquake were spared the expense of having to construct emergency headquarters buildings.
Those utilities include Kyushu Electric Power Co. and Kansai Electric Power Co. They are currently constructing emergency headquarters buildings under the new safety standards.
(This article was written by Ryuta Koike and Toshio Kawada.)