E-mailSitemapJapanese
Japan Nuclear Technology InstituteNihon Genshiryoku Gijyutu Kyokai
HOMEAbout JANTIAreas of ActivitiesNuclear FacilitiesRelated InformationContact Us
About JANTI
Information
Introduction
 Board Member
 Messages
Organization
      Overview
Organization
Logo Mark
Location
Member List


Onagawa Nuclear Power Station, Tohoku Electric Power Company
Published on November 18 '2011 : The Denki shinbun(The Electric Daily News)

Dr. Michio Ishikawa
Chief Adviser(Former President & CEO)
Japan Nuclear Technology Institute(JANTI)

The Onagawa Nuclear Power Station has three nuclear reactors with a total output of approxiamtely 2,170 MWe, located on the east side of OshikaPeninsula, Miyagi, facing the Pacific Ocean.

The Onagawa Nuclear Power Station was also struck by tsunami waves triggered by the Great East Japan Earthquake on March 11.Fortunately, since this power station was situated on higher ground and was spared the loss of off-site power, the site escaped a disaster like the one seen at the Fukushima Daiichi Nuclear Power station.

Yet, the tsunami waves left extensive damage.The third basement of the annex to Unit 2's reactor building became flooded when seawater entered from a tide gauge opening through pipes and tunnels, and one of the power supply panels at Unit 1's turbine building was burnt as a result of electrical leak.

Power station personnel are most busy in the 10 hours after the suspension of power generation until it reaches cold shutdown.This power station experienced an earthquake-triggered shutdown as well as flooding and fire.Plant personnel were scrambling to address the situation amidst a series of aftershocks and under a tsunami evacuation order.

During this chaos, about 100 local Onagawa residents knocked on the gates of the power station, seeking shelter.It was a group of locals including the elderly and small children who came in the cold evening under snowy drizzles.

Onagawa suffered devastating damage from the tsunami, which left about 10% of all residents or 980 people either dead or missing.With the town office and roads destroyed, evacuation instructions could not be sufficiently delivered.

Some affected residents who were gathered at the local gathering place voiced they should turn to the power station for evacuation, and walked a mountain path, still shaking from aftershocks, to reach the station's front gate.

Since the 9.11 terrorist attacks, people wishing to enter a nuclear power station are required to go through advance procedures.However, desperate times call for desperate measures.The power station's general manager allowed them in, saying that human life came first.The local residents were able to heave a sigh of relief, knowing that they were free from fear and the freezing temperatures.

Since then until June 6, the power station's gymnasium became a shelter for affected residents.The number of evacuees continued to grow as word spread, to reach as many as 360 at one point.

The biggest problem was food supply.With not enough food in reserve, evacuees survived on 2 meals a day, while plant personnel managed with just one meal a day, for several days until the arrival of relief supplies from the Sendai head office.This spirit of self sacrifice was a noble act.I can truly empathize with the hardship, having lived through post-war days of food shortages.

One episode that gave people high spirits in the life of evacuation at the power station was the birth of a healthy baby from a mother who was sent from the power station to Sendai by helicopter.However, NHK, which is supposed to be the nation’s public broadcaster, aired footage that only emphasized evacuees' anxiety, while completely ignoring the sense of gratitude and joy expressed by the baby's mother.

The only means for the power station to communicate with the external world was the utility’s private telephone line connected to the head office.Mobile phones and satellite phones were down due to network congestion.Many of the plant personnel could not contact their families.Steep roads of OshikaPeninsula were damaged and severed in the earthquake, disrupting traffic.

Fortunately, the power station had heavy machinery for on-site work.Plant personnel themselves used them to start road restoration work, which they were not used to doing.Five days of hard work paid off, when the road was reopened, allowing workers who live in Onagawa to take over.

Plant personnel returned to Onagawa, only to hear the sad news that there were misfortunes of family members of eight of their colleagues from the disaster.IAEA commended the personnel of Fukushima Daiichi Nuclear Power Station for their "selfless dedication to public interest".The same can be said about the workers at Onagawa.

In mid October, when I visited the Onagawa Nuclear Power Station, the site's ground surfaces remained distorted into waves.Damages were also observed at joints of other buildings that were not directly involved with nuclear generation.However, once I stepped inside the reactor facility, all the floors were as level as water surface, and everything was orderly.

OshikaPeninsula apparently sank around 1 meter, but that did not affect the nuclear facilities at all, which were built onto bedrock.Seismic safety design fulfilled its responsibility, but only in terms of structures and their resilience.The issue of tsunami was never discussed as part of seismic safety action.

The state of the affected nuclear power stations is a clear reminder of insufficient human wisdom, areas of improvement taught by experience.

 

  (End)

 

HOME | About JANTI | Areas of Activities | Nuclear Facilities | Rerated Information | Contact Us