Follow-up IAEA mission publishes findings

27 February 2008

A second inspection team from the International Atomic Energy Agency (IAEA) to Tokyo Electric Power Co's (Tepco's) Kashiwazaki Kariwa nuclear power plant confirmed there was no significant damage to the parts of the plant important to safety as a result of the earthquake which struck in July 2007.

Kashiwazaki - IAEA mission 
IAEA inspection team visiting Kashiwazaki-Kariwa (Image: Tepco)

The 12-member team of experts visited Japan between 28 January and 1 February at the request of the Japanese Nuclear and Industrial Safety Agency (NISA). The mission was tasked with focusing on three particular areas: seismic safety, the integrity of the plant and fire safety. The team held meetings with regulators, geologists, seismologists and Tepco. It also visited the Kashiwazaki Kariwa plant.

Philippe Jamet, head of the IAEA's Division of Installation Safety and leader of the mission, said: "The first objective of the team has been to confirm that there appears to be no significant damage to the integrity of the plant." The team was able to view key internal components in the plant inaccessible during their first inspection in August 2007.

The second IAEA fact finding mission investigating the effects of the earthquake on the plant has now published its findings. The report said that although there was no significant damage to the safety equipment of the plant, "no international regulation or experience" is readily available to precisely characterize the effects of the quake.

 "The IAEA is in a
  position to provide
  expertise to apply
  to the event...
  nuclear power
  safety standards
  will benefit"
The  report said that in order to understand the earthquake and to assess the possibility of future earthquakes that may affect the nuclear power plant, a large amount of "high quality" work has been performed by Japanese experts. This involved geophysical, geological, geodetic and seismological investigations both onshore and offshore. The report added that they will now have to assemble all the data within a coherent framework to produce an appropriately conservative seismic evaluation. The team suggest that "making the adequate use of the IAEA Safety Standards will facilitate the process of integration and synthesis, this providing a unique example for the international nuclear community."

Jamet said, "The IAEA is in a position to provide international expertise to apply to the event and in so doing international nuclear power safety standards will benefit."

The follow-up mission's report said that for the international community, it was an "invaluable chance to share the experience of Japan and learn from this event through seminars, workshops and site visits organized by the IAEA, NISA and Tepco." It added, "It was well understood that public perception, the need for outreach and a consistent flow of information to the community are critical components for dealing with a post earthquake situation."

IAEA director general Mohamed ElBaradei said that an international response to the earthquake is appropriate because of its relevance to other nuclear plants worldwide. He welcomed Japan's continued cooperation with the effort.

At the time of the magnitude 6.8 earthquake, three of the seven boiling water reactors at Kashiwazaki Kariwa - units 3, 4 and 7 - were in operation. Those reactors shut down safely as tremors began. Unit 2 was in the process of starting operation, and shut down automatically as well. Units 1, 5 and 6 were not operating as periodic inspections were being carried out. However, water containing trace amounts of radioactivity was shaken from cooling pools of all the units and some of this drained away to be discharged to sea. In addition, many barrels of solid radioactive waste were knocked over and an external electrical transformer failed and caught fire. All the reactors remain offline although the extensive checks required are now all but completed. After repairs, which would be likely to take a long time, the units should all restart operation.