Tuesday, April 05, 2011

Fukushima: time for the IAEA to take direct responsibility for the operation.

TEPCO have just dumped 11,500 tonnes of radioactive water into the sea, in order to create space for the 60,000 tonnes of more highly radioactive water that has accumulated in the reactors.

Traces of radioactivity is showing up in samples of edible fish.

This discharge of radioactivity to the environment can and must be stopped.

First, it is time for the IAEA to take over direct responsibility for managing the Fukushima rescue operation.  By dumping to sea, TEPCO is making it an international problem. 

The present situation is that control has been lost. The fission process is starting up again in at least one of the reactors, which means ever greater heat, more leakage, and more radiation which means more difficulty in getting close enough to do remedial work.

This means that we probably have to abandon all hope of keeping the reactors cool.

The hot fuel will burn its way down to the water table, forming steam, which will leak out through the soil, possibly sometimes with explosive force.

So what can we do? I have heard unconfirmed reports that ther is a US  plan. Bomb it. Yes, you heard: Bomb Fukushima. From the side you understand, so it tips over into the sea, which will automatically cool it, and also disperse it so that the fission reaction stops.

I only mention this to show how desperate people are getting, and to show how sensible is the Emergency containment solution I am putting forward here.

The principle is that, given the reaction itself is out of control, we must apply ourselves to controlling the emissions to the environment.

These emissions occur in two main ways: air and water.

Air Pollution

I have dealt here with the solution to air emissions: cap the reactors with fabric, draw off the contaminated air, filter off the radioactivity, and store.

This atmospheric emissions solution should start tomorrow with Reactor No 2, pictured below:

Photo: REUTERS / Japan Defense Ministry

The rectangular window should be fitted with a duct through which the steam can be drawn and passed to a series of filters. The filter design choice can be a combination of particle filter, cyclone, ion-exchange washing or any other suitable modality. It is simple, bog-standard engineering. The filters can be changed, modified and added to to the heart's content of the engineers involved. Reactor 2 will be the pilot for the other, damaged reactors, which will need the more challenging fabric containment before their gases can be captured.

Water Pollution

Again, the engineering for this is simple. I am grateful to an engineer, @BottomfedBhudda (yes, I know) for this. 

We drill two holes, one deep, one shallow.

The aim of the deep one is to lower the level of the ground water. It will yield cold, clean, fresh (or brackish) water which can be used for the cooling operation. Lowering the ground water will give more time before the radionuclides come in contact with it - because once the groundwater is contaminates, radiation will diffuse through aquifers to remote sources of water.

The shallower drill will pick up contaminated water filtering down from the reactors.

This contaminated water will be passed first through a physical filter to trap particles, and then a series of ion-exchange resins and any other process that would reduce, including chemical reactions designed to precipitate out the dissolved radionuclides. 

Again, the treated water can be fed back as coolant.

So, much can be done to mitigate the Fukushima disaster. The engineering is simple. The most difficult bit is to  get the message through to the decision makers in a timely way. 

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