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Japan's Nuclear Reactor Crisis Worsens

March 15, 2011

On March 15, a fire started in the spent fuel pool at Fukushima Daiichi Unit-4 and an explosion occurred in Fukushima Daiichi Unit-2. Reports indicate that the fire has been extinguished. Japanese officials have now told people within a 30 kilometers radius not to leave their homes. Radiation levels above 20 times background levels in Tokyo have been reported.


On Friday March 11, the largest earthquake in Japanese history (8.9) hit the eastern coast of Japan, causing the shutdown of reactors at Fukushima nuclear power station. Backup power for the Fukushima Daiichi Unit-1 reactor failed after an hour likely due to flooding from the tsunami.  Since then, the cooling system of another reactor at the Fukushima Daiichi was lost, and problems with cooling have been reported with Fukushima Daini reactors. The lack of backup power puts the cooling system at risk. The cooling system keeps the extremely hot nuclear core from melting down, as well as the spent fuel rods in large pools from overheating and causing a fire.

On March 12, a buildup of hydrogen caused an explosion in the turbine room at the Fukushima Daiichi Unit-1 reactor in Japan.  The Japanese government is reporting that the reactor vessel is intact, but it is not known if the explosion caused any damage to it. Hydrogen is building up in the Fukushima Daiichi Unit-3 reactor, which could result in another explosion.

 On March 13, Japanese officials announced that there have been partial meltdowns at two reactors and another three reactors have lost power for cooling.  At least one nuclear worker has died, three others have been seriously exposed, and another 160 contaminated.  The government is evacuating the 200,000 people living within 20 kilometers (12 miles) of the reactors and is also reported to be distributing potassium iodine pills to reduce the risk of thyroid cancer.  In a desperate effort to prevent a nuclear meltdown, the reactor operator is flooding at least two reactors with seawater. 

Since 2010, Fukushima Daiichi Unit-3 reactor had been using mixed-oxide fuel (also called plutonium fuel), which is even more dangerous to the public than a severe accident with uranium fuel.  Plutonium fuel contains plutonium and other very toxic actinides that would increase the number of resulting cancers.  Current reports say that this fuel has been exposed to air. 

Pressure in at least two of the reactors have reported to be well above normal levels and the reactor operator, Tokyo Electric Power Co., released some of the pressure by venting radioactive vapor from the containment structure.  In addition, the radionuclide cesium has been reportedly found outside the reactor, which indicates that there has been fuel damage.

In the morning on March 14, the reactor containment building at Fukushima Daiichi Unit-3 had an explosion as the result of a build-up of hydrogen.  Initial analysis suggests that the containment remains intact.  Eleven workers were injured in the blast.  There is a potential that the spent fuel pool were damaged in the explosion. The spent fuel pool is located just below the roof of the building (which blew off).  Experts are concerned that the explosion rained debris onto the spent fuel bundles or knocked the bundles together which could have damaged them, and sent the irradiated fuel chunks to the bottom of the pool where they could reach critical mass.

Additional resources:

March 12 press conference with nuclear experts, including PSR’s Dr. Ira Helfand

CDC Potassium Iodide fact sheet

PSR fact sheet on radiation and health

Japan Earthquake/Nuclear Power – How Big a Risk of Disaster?

March 13 press conference by Japanese organization Citizens' Nuclear Information Center (CNIC)

March 12 statement from the Japanese organization Citizens' Nuclear Information Center (CNIC) on the Nuclear and Earthquake Disaster Unfolding in Japan

PSR will continue to update our site on the situation. 

PSR Staff and Board Members Available for Media Calls re Medical Consequences of Japan’s Nuclear Reactor Accident:

Michele Boyd
Safe Energy Director

(202) 587-5242 (o)
(202) 494-0785 (c)

Ira Helfand, MD 
Leeds, MA 01053
413-320-7829 (c)
413-584-5933 (h)

Peter Wilk, MD
Executive Director
Washington, DC 20009
202-587-5240 (o)
703-402-0632 (c)

Robert Gould, MD
San Francisco, CA
408-972-7299 (w)
415-864-6758 (h)
415-407-8972 (cell)
415-407-8806 (cell)
707-677-0502 landline

Richard Grady, MD
Seattle, WA 98115
206-601-2802 (m)
206 526-0551 (h)
206 987-2130 (o)

Andy Kanter, MD, MPH
PSR President Elect
New York, NY 10033
Office:  212-305 4842 
Cell: +646- 469 2421

Jeff Patterson, DO
Madison, WI
608-256-3983 (h)
608-206-2101 (c)


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