Column of the Day: What’s happening in Fukushima?

9/20,Japanese government declared Fukushima nuclear plants can be settled (kept under 100C) (“cold shutdown”) by the end of this year.

Link

However,Koide from Kyoto university warns it is too unrealistic.

As he says,we do not know where the fuel rods in the reactors.We do not even know how the vessels are right now.

They managed to fix the water measurement is reactor 1,but the measurements are broken in reactor 2 and 3. We do not even know where the water is which they keep giving in.

9/20,Tepco admitted hundreds of tons of water flow into the basement floor of each reactor on the daily basis.

Tokyo newspaper reported there were 100,000 tons of water.It must be reduced to 51,600 tons after pumping by 9/13.However,there is estimated at least 81,300 tons water still.

Tepco has been explaining it is because of water,but still it’s too much.

Tokyo newspaper reports there is possibility that groundwater is flowing into the basement floor from the cracks.

From the view of a civil engineer (me),another possibility is that water is coming from “the sea”.It sounds more rational that there is a crack / cracks to connect the basement floor and sea,and sea water comes into the basement floor.

If so,no matter how much they pump up the water,water keeps coming in by siphon effect until the surface is as high as sea water level.(the same mechanism of toilet)

Koide estimates nuclear fuel rods may be now 12m deep under ground at reactor 1-3. Only God knows about reactor 4.

Melted rods can not be taken out for 1~2 years. One piece of the fuel rods is estimated to sink into the ground at a rate of 17m per year. Therefore, 2 years from now,they may be 34m underground.

Yesterday,they detected 1.38 uSv/h in Tokyo University.

http://kipuka.blog70.fc2.com/blog-entry-423.html