Japan: IAEA Updates On Nuclear Disaster; Injuries, Radiation And Temperature

Based on a press release from the Japanese Chief Cabinet Secretary dated 16 March 2011, the IAEA can confirm the following information about human injuries or contamination at the Fukushima Daiichi nuclear power plant.

Please note that this list provides a snapshot of the latest information made available to the IAEA by Japanese authorities. Given the fluid situation at the plant, this information is subject to change.

Injuries

• 2 TEPCO employees have minor injuries
• 2 subcontractor employees are injured, one person suffered broken legs and one person whose condition is unknown was transported to the hospital
• 2 people are missing
• 2 people were ‘suddenly taken ill’
• 2 TEPCO employees were transported to hospital during the time of donning respiratory protection in the control centre
• 4 people (2 TEPCO employees, 2 subcontractor employees) sustained minor injuries due to the explosion at unit 1 on 11 March and were transported to the hospital
• 11 people (4 TEPCO employees, 3 subcontractor employees and 4 Japanese civil defense workers) were injured due to the explosion at unit 3 on 14 March

Radiological Contamination

• 17 people (9 TEPCO employees, 8 subcontractor employees) suffered from deposition of radioactive material to their faces, but were not taken to the hospital because of low levels of exposure
• One worker suffered from significant exposure during ‘vent work,’ and was transported to an offsite center
• 2 policemen who were exposed to radiation were decontaminated
• Firemen who were exposed to radiation are under investigation

Temperature of Spent Fuel Pools at Fukushima Daiichi Nuclear Power Plant

Spent fuel that has been removed from a nuclear reactor generates intense heat and is typically stored in a water-filled spent fuel pool to cool it and provide protection from its radioactivity. Water in a spent fuel pool is continuously cooled to remove heat produced by spent fuel assemblies. According to IAEA experts, a typical spent fuel pool temperature is kept below 25 ˚C under normal operating conditions. The temperature of a spent fuel pool is maintained by constant cooling, which requires a constant power source.

Given the intense heat and radiation that spent fuel assemblies can generate, spent fuel pools must be constantly checked for water level and temperature. If fuel is no longer covered by water or temperatures reach a boiling point, fuel can become exposed and create a risk of radioactive release. The concern about the spent fuel pools at Fukushima Daiichi is that sources of power to cool the pools may have been compromised.