Dumping water from the Japanese nuclear plant into the sea

Dear All,

I have read that the Japanese plant operators are pumping radioactive water into the sea without treatment. While this might sound alarming, it is important to understand that this is not the most radioactive water waste from the site.

The water which is being pumped into the sea is ” 10 000 ton of low level contaminated water from their radioactive waste treatment” (http://www.iaea.org/newscenter/news/tsunamiupdate01.html) which is being poured away to make space for the much more radioactive water from the basement of unit two. TEPCO have estimated that if a person was to eat seaweed and seafood from near the plant that they would get a dose of 0.6 mSv.

I do not know how much activity (Bq per litre) is in the discharged water, if any of my readers finds out then please send me a message in the form of a comment.

I hold the view that even if it is not possible to chemically treat the contaminated waste water that the most radioactive waste water should be isolated in a tank as long as possible. This is to allow the iodine-131 and the other shortlived isotopes  to decay away. It also buys more time to allow someone to find equipment which can clean the water up.

If the water was held in a tank for two weeks then the iodine-131 level would drop by a factor of almost four, which would be a good thing.

In the ideal world the water would be treated with a zeolite, an ion exchange column or by floccing to remove the radioactive metals before it is released. My targets would be to try to remove solid particles, the cesium and the other metals.

It is important to bear in mind that the Bq is a very small unit, its use is a bit like expressing my weight using grains of rice as the unit of weight.