March 17, 2011
Status of JNFL facilities and actions taken for the East Japan Great Earthquake Disaster
As a result of the equipment inspection conducted following the East Japan Great Earthquake Disaster that occurred around 14:46, Friday, March 11, 2011, JNFL facilities presently have no problems and all safety-critical equipment of these facilities is operated under normal condition.
The radiation dose around each of these facilities remains unchanged from its normal value.
1. Impact on JNFL facilities
According to the observation data within the Reprocessing Plant Business Site, a seismic motion of approximately 37gal was observed at the Separation Building (reference observation point used for reports to Safety Agency) , which is sufficiently smaller than the design value based on the reference seismic motion of 450gal. The earthquake has no significant impact on our buildings and facilities, although there were a "leak from the piping to supply heavy oil to the backup diesel generator" and a "pool water leak in the Spent Fuel Storage Building" which both of them has been already retrieved.
2. Actions taken after the Earthquake
Immediately after the Earthquake occurred, JNFL has set up the company-wide taskforce lead by the President. Inspections of the facilities and checking of monitoring posts were performed. As well as all the important information was transmitted to relevant organizations. Also, the information was released on our website.
3. Power supply status
- 14:46, Friday, March 11: Upon loss of off-site power supply to Reprocessing Plant, Vitrified Waste Storage Center, Uranium Enrichment Plant, and Low-Level Radioactive Waste Disposal Center due to the Earthquake, in-house emergency power was supplied to these facilities simultaneously.
- 22:22, Sunday, March 13: The necessary power supply to Reprocessing Plant, except Spent Fuel Receiving and Storage facility, were switched from emergency to normal off-site commercial power.
- 15:12, Monday, March 14: Uranium Enrichment Plant was switched from emergency to normal off-site commercial power.
- By 5:10, Tuesday, March 15: Including Spent Fuel Receiving and Storage facility, all power supplies necessary for the safety of Reprocessing plant were switched from emergency to commercial power.
- 10:03, Tuesday, March 15: Low-Level Radioactive Waste Disposal Center was switched to normal off-site commercial power.
- By 11:25, Tuesday, March 15: All power supplies necessary for the safety of Vitrified Waste Storage Center were switched from emergency to normal off-site commercial power.
4. Tsunami assessment
The Reprocessing Plant Business Site is located at approximately 55m above the sea level. It is recognized that no tsunami will have a significant impact on the safety functions of the facility, which was approved by the national government in December last year.
(Reference) Safety measures for the Spent Fuel Receiving and Storage facility of the Reprocessing Plant
1. Difference between nuclear power stations and JNFL plant
(1) The period over which spent fuel is cooled in water after removal from reactors is significantly different between the fuel immediately after use for power generation at nuclear power stations and the spent fuel that is stored at JNFL plant.
(2) The spent fuel that is stored at JNFL plant is transported after it is appropriately cooled down for transportation at the nuclear power station.
(3) It is also cooled in the pool water after being transported to JNFL plant.
(4) JNFL plant is located on a plateau that is 5km away from the seashore and 55m above the sea level.
2. System backups
(1) JNFL plant is equipped with a system that is designed to cool down the pool water to cool the spent fuel in the storage pool. In case of failure of this system, the plant also has a backup system. When the operating system fails, it will be switched to the backup system.
(2) The system to make up the pool water (approx. 500m3) also has a backup in case of its failure.
3. Securing power supply
(1) When off-site power supply stops after an earthquake, power can be supplied from emergency diesel generators.
(2) After this Earthquake, off-site power supply has stopped completely, but the emergency diesel generators started up to supply power to the equipment necessary to ensure safety. (At present, emergency diesel generator fuel is secured enough to operate generators for approximately one month.)
(3) At the nuclear power station in Fukushima, emergency power supply has also stopped due to the tsunami that occurred after the Earthquake. Since our plant is located on a plateau that is approximately 55m above the sea level and 5km away from the seashore, it will not be affected by tsunami.
4. Actions to take when power supply stops
(1) To supply water to the pool in the event power supply stops, we have three mobile fire pumps and two fire trucks to supply water from a firefighting reservoir (approx. 900m3), firefighting water tanks (approx 40m3 x 38 units), and a reservoir (approx. 10,000m3).