Fukushima: Progress is nice

[RobertEarl]

It has been 31 months since 3/11 and we see progress being made.

One of the most immediate dangers is being effectively tackled. In the one fuel pool that was most in danger of spilling its radioactive materials onto the ground, Japan has executed a removal of the rods program that passed its first hurdle.

First alerted to us by US Senator Ron Wyden (D) of Oregon, the damaged building holding the pool some 50 feet above ground, is slowly being emptied. And we all pray they are successful. Thanks, Sen. Wyden, for sticking your neck out and telling us the Truth.

Next up is how to keep groundwater from flowing through the reactor buildings. Not only is the ground water carrying off radioactive materials into the Pacific, that water is also detrimental to the building's solidarity. If the ground becomes saturated and an earthquake strikes, the ground could liquefy causing instability of three buildings that hold more spent fuel pools, again 50 feet above ground.

One plan is to freeze the ground around the buildings, in effect placing an underground ice wall as a barrier to ground water flows. Several mines use such a barrier. But none on such a scale as needed at Fukushima.

Water everywhere, and especially radioactive water, is the next big problem. Thankfully, Japan is now accepting help from outside experts, so this problem may soon find solutions that save the Pacific from being further polluted.

[RobertEarl]

1. Where is the water coming from?

To the west of Fukushima rise a mountain range of some height. Rains that fall on that mountain either soak into the ground or runoff via streams.

Water that soaks into the ground moves at a snails pace, going down hill over time.

Where Fukushima sits is next to the Pacific ocean. Water in the ocean exists as a barrier to ground water flows. In effect it forces ground water that makes it to the ocean to rise to the surface. Fresh water will float on top of salt water which adds to the upward force of the ground water. So, at the line where the two waters meet, sits Fukushima and always Fukushima has had a high ground water level.

One thing that Tepco did was build a metal wall between the plant and the ocean, hoping to keep the polluted ground water from flowing into the ocean. It worked. But now the ground water is topping that barrier, and saturating the ground upstream under the reactors. That wall may have been a mistake. Testing of that ground water on the reactor side is showing alarmingly high levels of radioactivity. That testing shows that the reactors are leaking into the ground water.

[RobertEarl]

2. The buildings and how they sit

There are four reactor buildings in question. Each is approximately 6 stories above ground and two below ground. Well, two of the four now have the top three stories removed.

In the ground is what is called basements. When built, the basements were engineered to block most ground water flows and drains were built to divert some flows. Also pumps installed to pump out water that collected in the basements.

The earthquakes likely damaged the walls below ground as well as above. There are now likely some cracks that ground water can easily seep through. Now that the ground water levels have become artificially higher due to the aforementioned wall built toward the ocean, the seeps are even more likely to seep.

Considering the actions of water as a solvent, witnessed by what it can do to solid rock that gets in its way, it is a concern that the concrete that makes up the basement walls will weaken and erode over time. Added to the actions of the water are the effects of radiation and heat.

Removal of the water is not a simple task. The water is heavily polluted so it can not, by law, be pumped out and let into the ocean. What Tepco has done is set up filters that they run the water through. Of course those filters now have become highly concentrated with radioactive elements. They have been filling tanks with that highly concentrated water and there now exists a large area of tanks full of highly dangerous water.

[RobertEarl]

3. Fuel pools

At each reactor building are deep pools of water designed to hold the nuclear fuel before and after it is used in the reactor. The bottom of each of these polls is 50 feet above ground. The top near 100.

The reactors are connected to the pools and there is a gate between the reactors and the pools through which the fuel rods are moved. Only those rods which have not been used and those rods which have cooled for years in the pools, are rods that can be raised out of the water in the pools.

In the case of the number 4 fuel pool, there are two classes of rods. Mostly there are spent fuel rods; rods that have been in the reactor and used to heat water. These are at various stages of cooling due to different ages.

These rods are what they call irradiated rods and they radiate radiation at rates depending on how old they are. Some rods, one reactor full, having been moved from the reactor just before 3/11/11 are still quite hot. These rods are very dangerous to move as they still radiate tremendous radiation and can get hot very fast if exposed to air. These have to remain in water during movement.

The other class are unused rods that had been placed in the pool ready to go to work in the reactor. Once activated they can create that tremendous heat that makes the reactors work. The fear is that they may become activated and go critical during the move.

[flamingdem]

4. Good on Wyden

very, very good.