"and to lay him before him" - (Hydrogen Explosion)

Onahama Port, Iwaki City, 2 months after the tsunami

Iwaki City, Fukushima Prefecture

Fukushima Prefecture, Japan

(Photos taken by EEE Reporter; click to enlarge.)


Hydrogen Explosion

For nuclear power generation, 99% of efforts should be spent for prevention of leakage of radioactive material.

For this purpose, any explosion in the reactor building and the reactor vessel should be avoided.

Higher pressure could destroy the reactor vessel, leading to spraying and scattering of radioactive material into the environment.

Higher temperature could cause meltdown of uranium fuel, and generation of hydrogen gas inside the pressure vessel and its explosion in the reactor building.

The worst case is the bursting of the pressure vessel due to higher pressure. The second worst is the hydrogen explosion inside the reactor building. And, the last is the meltdown of uranium fuel.

But, it is not so complicated. If utility companies spend 10 times more money for protective measures, these possible accidents can be surely avoided. So, the true issue is that power companies are not educated so as to take full measures for disaster prevention by spending money as much as possible.

However, it is true that it is thought that it could happen only once in 1000 years that the beach where Fukuhsima Daiich Plant stands would suffer from a 15-meter high tsunami triggered by an M9.0 earthquake.


SECTION I: Hydrogen Explosion in Reactor Building

The mechanism that induced hydrogen gas in Fukushima Daiichi reactors is described as follows:

Zr (zirconium) ＋ 2H2O (water) --> ZrO2 (zirconia) ＋ 2H2 (hydrogen)

Zirconium is used as material for a metal frame to hold uranium fuel.

When uranium fuel got heated due to a lack of coolant water, its heat melts the metal frame so that zirconium seeps out of the metal frame to touch water inside the pressure vessel. Then, zirconium is changed to zirconia, inducing hydrogen gas out of the water.

This hydrogen, when meeting oxygen in the reactor building space out of the containment vessel, exploded to cause the large scale radioactive contamination around Fukushima Daiichi on March 12, 2011, even threatening Tokyo at one time.

Hydrogen Gas: Metal frame for uranium fuel --> Pressure vessel --> Containment vessel --> Reactor building --> Explosion

It is apparent that a frame to hold uranium fuel must have been made of material that never induces hydrogen gas when heated due to a trouble in the pressure vessel. It is a basic design problem. Improvement at this point can allow for avoidance of the kind of explosion as observed in Fukushima Daiichi. It is so basic and simple. It is a matter of material for a frame to hold uranium fuel.

Note that walls and floors of the reactor building are made of 1 to 2 meter thick concrete plates and slabs. And, reportedly the foundation of the building is 8 meters thick. The ceiling is reportedly made weak intentionally so that a possible explosion would have its bomb blast escape the building.

SECTION II: Not Uranium but Zirconium that is Dangerous

But why was zirconium adopted for component material in the nuclear reactor?

Published on Saturday, March 12, 2011 by CommonDreams.org
Behind the Hydrogen Explosion at the Fukushima Nuclear Plant
by Karl Grossman
...
That is because a highly volatile substance called zirconium was chosen back in the 1940's and 50's, when plans were first developed to build nuclear power plants, as the material to be used to make the rods into which radioactive fuel would be loaded.

There are 30,000 to 40,000 rods—composed of twenty tons of zirconium—in an average nuclear power plant. Many other substances were tried, particularly stainless steel, but only zirconium worked well. That's because zirconium, it was found, allows neutrons from the fuel pellets in the rods to pass freely between the rods and thus a nuclear chain reaction to be sustained.

But there's a huge problem with zirconium—it is highly volatile and when hot will explode spontaneously upon contact with air, water or steam.

The only other major commercial use of zirconium through the years has been in flashbulbs used in photography. A speck of it, on a flashbulb, ignites to provide a flash of light.

But in a nuclear plant, we're not talking about specks—but tons and tons of zirconium, put together as a compound called "zircaloy" that clads tens of thousands of fuel rods.

Heat, a great deal of heat, builds up in a very short time with any interruption of coolant flow in a nuclear power plant—the problem at Fukushima after the earthquake that struck Japan.

Zirconium, with the explosive power, pound for pound, of nitroglycerine, will catch fire and explode at a temperature of 2,000 degrees Fahrenheit, well below the 5,000 degree temperature of a meltdown.

Before then, however, zirconium reacts to the heat by drawing oxygen from water and steam and letting off hydrogen, which itself can explode—and is said to have done so at Fukushima.

As a result of such a hydrogen explosion, there is additional heat—bringing the zirconium itself closer and closer to its explosive level.

Whether in addition to being a hydrogen explosion, zirconium also exploded at Fukushima remains to be known.

But what has happened regarding hydrogen at Fukushima, like the "hydrogen bubble" when the Three Mile Island plant in Pennsylvania underwent its near partial meltdown, is no mystery—but precisely what is expected in a loss-of-coolant accident.

It is described in U.S. government and nuclear industry accident studies as a "metal-water" reaction. It's a reaction, the research has long stated, that can easily trigger a meltdown.

Using tons of a material otherwise used as the speck that explodes in a flashbulb in nuclear power plants —yes, absolutely crazy.
http://www.commondreams.org/view/2011/03/12-3

Yet, a new type of fuel rods with a stainless steel frame is now manufactured and introduced into the reactor, so that hydrogen explosion can be avoided.

Anyway, when some engineers decided to use zircaloy for a metal frame to house uranium fuel in 1950's, the fate of Fukushima Daiichi of 2011 was decided. It was not meltdown of uranium fuel inside the pressure vessel but hydrogen gas generated through interaction between zircaloy and water at a temperature lower than that for meltdown that caused this large-scale nuclear contamination accident in Fukushima Daiichi.

*** *** ***

There are many arguments about how much radioactive contamination has expanded around the Fukushima Daiichi Nuclear Plant.

Some say that it is more than Chernobyl; Others (mostly those close to the Government) say it is not dangerous for children to receive 20 milli sieverts per year. Anyway, data is collected by various parties concerned, including the US Government.

(Click to enlarge.)
http://matome.naver.jp/odai/2130151305764164901





(Not only samurai, but townsmen and gangsters belted on a kind of swords once in Japan.
http://www.youtube.com/watch?v=Kj01Nv3lqwI&feature=related)



Luk 5:18 And, behold, men brought in a bed a man which was taken with a palsy: and they sought means to bring him in, and to lay him before him.

Luk 5:19 And when they could not find by what way they might bring him in because of the multitude, they went upon the housetop, and let him down through the tiling with his couch into the midst before Jesus.

Luk 5:20 And when he saw their faith, he said unto him, Man, thy sins are forgiven thee.