News Brief, 4/1/11
Status of Reactors
Efforts are still underway to pump water from the turbine buildings of the reactors. Water in the turbine buildings is being pumped directly into the reactors’ condensers. The IAEA reported yesterday that the condenser of Unit 1 has been completely filled and that the pumping of water from Unit 1’s turbine building has ceased.
All units are currently being cooled by injection of fresh water, using temporary pumps, with backup power supplies in place in case of further electrical power issues. TEPCO reports that water temperatures in the units are below 100 C in the pressure suppression chambers, and that no reactor coolant is being leaked to containment.
Radiation Measurements
Air monitoring data for the region can be found at http://www.mext.go.jp/english/radioactivity_level/detail/1303986.htm .
An isolated location outside the boundary of the evacuation zone displayed high levels of deposition of Iodine-131. The IAEA has announced that these levels, found in the village of Iitate, exceed their guidelines for evacuation. Local officials are assessing the situation.
Testing of various food products from the prefectures surrounding the damaged reactors show that all of the food product samples from outside Fukushima prefecture display either no radioactivity or levels below regulatory limits. However, 25 samples from the Fukushima prefecture did exceed Japanese regulatory limits.
Radiation levels in seawater immediately adjacent to the plant’s discharge canal rose yesterday (http://www.tepco.co.jp/en/press/corp-com/release/11033109-e.html) . The cause of this increase is still not known.
The EPA has continued to monitor the potential pathways for radiation exposure of the U.S. population. To date, radiation detected in milk is on the order of picocuries (10-12 Curie) per liter. This is 5,000 times lower than the FDA’s Derived Intervention Level. A Derived Intervention Level is the point at which the FDA would act to take the food in question out of our food supply. The level considers what fraction of the diet is made up by that food (very conservative numbers are used), how often it is drunk, and for how long people are exposed.
Similarly, the trace levels of radioactivity being detected in rainwater in the U.S. have been deemed far too low to be of consequence to human health. Levels in the air on the western coast of the U.S. continue to fluctuate about the natural level of background radiation, and are of no concern.