Tsunami Countermeasures at Hamaoka Nuclear Power Station
July 22, 2011
Chubu Electric Power Co.,Inc.
This is to announce that Chubu Electric Power has established tsunami countermeasures for the Hamaoka Nuclear Power Station that reflect knowledge learned heretofore, including from the recent accident caused by the Tohoku-Pacific Ocean Earthquake at the Tokyo Electric Power Co., Inc.'s Fukushima Daiichi Nuclear Power Station.
Because we take society's increased concerns about the safety of nuclear power very seriously, the tsunami countermeasures announced herein are intended to enhance the safety of the Hamaoka Nuclear Power Station.
We are confirming the Hamaoka Nuclear Power Station's safety against tsunami, taking into account tsunami that have had a major impact on the area in the past, such as those from the Ansei-Tokai and Hoei earthquakes. Additionally, we have completed emergency safety measures that considered the accident caused by the Tohoku-Pacific Ocean earthquake at the Fukushima Daiichi Nuclear Power Station.
Under the current tsunami countermeasures, we have decided to take two sets of "flooding prevention measures," namely 1) measures such as building a breakwater to prevent flooding on the station grounds, and 2) measures to prevent flooding in buildings if there is flooding on the station grounds. In addition, we will "strengthen emergency countermeasures" to ensure multiple and diverse cooling functions so that reactors can be reliably and safely brought to cold shutdown even in the event of "complete loss of AC power" and "loss of seawater cooling function," problems that occurred at the Fukushima Daiichi Nuclear Power Station.
We have decided that the breakwater to be built on the seaward side of the station grounds is to be T.P. (Tokyo Bay mean sea level) + 18 m, in light of the height of the dune embankment in front of the Hamaoka Nuclear Power Station (T.P. + 10 - 15 m) and the runup height of the tsunami that hit the Fukushima Daiichi Nuclear Power Station (T.P. + 15 m).
Moreover, we have investigated events such as combined Tokai/Tonankai/Nankai earthquakes and anticipate that the tsunami runup height at the Hamaoka Nuclear Power Station would be about T.P. + 8 m.
We created a virtual tsunami model of a magnitude 9 earthquake (the same as the Tohoku-Pacific Ocean Earthquake), and test results indicated that the height would be about T.P. + 10 m.
Chubu Electric Power will continue to take the necessary and appropriate measures based on new knowledge from studies of the accident at the Fukushima Daiichi Nuclear Power Station, the investigation of the Central Disaster Prevention Council, and so on.
Also, in light of knowledge from the accident at the Fukushima Daiichi Nuclear Power Station, we will anticipate the simultaneous occurrence of earthquake, tsunami and nuclear power station damage and, together with our Group companies, will work to revise and strengthen our disaster prevention system. We will respond appropriately in close partnership with local governments, etc. in their response to citizens in the event of disaster, offering our knowledge and proactively cooperating in other ways as well.
Chubu Electric Power's target is to complete the tsunami countermeasures announced today by December 2012 and thereby increase safety at the Hamaoka Nuclear Power Station. We will make every effort to explain these measures thoroughly so that the local community and the rest of society can feel reassured.
The content of these tsunami countermeasures will also be reported to the Ministry of Economy, Trade and Industry's Nuclear and Industrial Safety Agency.
[Flooding prevention measures]
[Flooding prevention measures 1]
Measures such as building a breakwater to prevent flooding on the station grounds
[Flooding prevention measures 2]
Maintain seawater cooling function and prevent flooding in buildings if there is flooding on the station grounds
[Strengthen emergency countermeasures]
[Strengthen emergency countermeasures]
Ensure cooling function in scenario that assumes complete loss of AC power and loss of seawater cooling function
* Construction costs for these tsunami countermeasures are estimated at approximately 100 billion yen; the impact on this term's performance will be insignificant.