Status update from IAEA March 20

Unit 1

Coolant within Unit 1 is covering about half of the fuel rods in the reactor, and Japanese authorities believe the core has been damaged.

There are no indications of problems with either the reactor pressure vessel or the primary containment vessel.

Efforts to pump seawater into the reactor core are continuing.

No precise information has been available on the status of the spent fuel pool.

On 19 March, the containment vessel pressure indication was restored.

Unit 2

Coolant within Unit 2 is covering about half of the fuel rods in the reactor, and Japanese authorities believe the core has been damaged. Following an explosion on 15 March, Japanese officials expressed concerns that the reactor’s containment may not be fully intact.

Efforts to pump seawater into the reactor core are continuing.

No precise information has been available on the status of the spent fuel pool. On 20 March, workers began pumping 40 tonnes of seawater into the spent fuel pool.

Unit 3

Coolant within Unit 3 is covering about half of the fuel rods in the reactor, and Japanese authorities believe the core has been damaged.

Following the explosion, Japanese officials expressed concerns that the reactor’s containment may not be fully intact.

Efforts to pump seawater into the reactor core are continuing.

Of additional concern at Unit 3 is the condition of the spent fuel pool in the building. There are indications that there is inadequate cooling water level in the pool. and Japanese authorities have addressed the problem by spraying water from trucks. Spraying from trucks continued on 20 March. There is no data on the temperature of the water in the pool.

Unit 4

All fuel from Unit 4 had been removed from the reactor core for routine maintenance before the earthquake and placed into the spent fuel pool.

Authorities remain concerned about the condition of the spent fuel pool, and Japanese Self Defence Forces began spraying water into the building on 20 March.

Units 5 and 6

Shut down for routine maintenance before the earthquake, both reactors achieved cold shutdown on 20 March. The reactors are now in a safe mode, with cooling systems stable and under control, and with low temperature and pressure within the reactor.

Instrumentation from both spent fuel pools had shown gradually increasing temperatures over the past few days. Officials configured two diesel generators at Unit 6 to power cooling and fresh-water replenishment systems in the spent fuel pools and cores of Units 5 and 6. As of 20 March, temperatures in both pools had decreased significantly.

Workers have opened holes in the roofs of both buildings to prevent the possible accumulation of hydrogen, which is suspected of causing explosions at other units.

Restoration of Off-site power

Progress has been achieved in restoring external power to the nuclear power plant, although it remains uncertain when full power will be available to all reactors. Off-site electrical power has been connected to an auxiliary transformer and distribution panels at Unit 2. Work continues toward energizing specific equipment within Unit 2.