March 26 2011: A reader, from CEA, sends me a (daily) report of the Institute of Nuclear and Radiological Protection, in French (IRSN), he precises ''this is the real information about site status of Fukushima''.
This report seems less optimistic that the one given by a French engineer living on site, and commenting information given by official Japanese services.
The report of IRSN of March 25th 2011
Institute of Nuclear and Radiological Protection
Situation of nuclear plants in Japan after major earthquake occurred March 11 2011
Point position on March 25 at 08h00
State of reactors
IRSN remains heavily preoccupied by the actual situation of reactors no 1,2 and 3 ( failure risk of some material because of the presence of massive quantities of salt in tanks and enclosures, lack of a sustainable system able to evacuate residual power...). That precariousness should last for weeks or months considering the difficulty.
IRSN examines scenarios of possible aggravation of the situation, notably conceivable scenarios in case of breaking tank of the reactor no 3. It will be difficult to demonstrate the reality of such a scenario but impact in term of radioactive rejects in environment is under consideration.
Reactor no 1
The injection rate of sea water in the tank has been adjusted (10 m3/h) for controlling temperature above the core. This rate must permit evacuation of residual power. Pressure measured in the containment enclosure has been stabilized. It shouldn't be necessary to depressurize this tank in a very short-term.
Reactor no 2
The injection of sea water in the tank is maintained for assuring cooling of the core, which stays partially out of water. The containment enclosure could be damaged. The situation has not evolved and depressurization operations of tank containment are not necessary at the moment. The control room should be replenished this day.
Reactor no 3
The injection of sea water in the tank would be maintained in order to ensure core cooling which stays, however, partially dewatered. The containment enclosure seems to be no more waterproof according to pressure indicators; this loss of seal would be at the origin of ''continuous'' and unfiltered radioactive discharges in the environment.
The release of smoke detected in March 23 has stopped. IRSN analyzes potentials causes of failure of containment of reactor no 3. One hypothesis examined by IRSN concerns the eventuality of a rupture of the tank followed by an interaction between corium (mixture of fuel and molten metal) and concrete at the bottom of the containment enclosure.
The impact in terms of rejects in environment is being examined. Three operators have been contaminated March 24 in the turbine building of the reactor no 3. Audit works of materials have been stopped. These works aim to restore a reactor feed in freshwater.
Reactor no 4
The core of this reactor does not contain fuel.
Reactor no 5 and 6
Reactors are correctly cooled (core and assembly in cooling pool).
It says that the concern of Japanese engineers is that salt provided by the cooling sea water blocks solenoid valves, which are only controllable from afar. A malfunction of this kind could have serious consequences and their concern is to revert back to a freshwater cooling.
So, what is the solution?
I have hot news, which are information of first hand, to communicate about Z-machine, since I have collected them in two congress internationals, Vilnius in 2008 and Jeju, Korea, October 2010, and close to Malcom Haines him-self. Nexus accepted to publish this news article, which will be released in the next issue. Those information will multiply jointly hopes and fears linked to this new technology of ultra-high temperatures. Without spoiling the charm of this subject (this news article will be quickly written):
- Americans have achieved 3,7 billions of degrees in 2005 in Z-machine of Sandia. Opting for military applications in priority (pure fusion bomb), they misinform anything goes. With ZR, the electrical intensity increased from 17 to 26 million amps and performances of the machine are now kept secret.
March 20 2011: Is it important to make a serial with this Japanese's accident? There are so many disasters on Earth that we are saturated. What we can say is that this disaster is due to another human's bloody thing: building nuclear plants on costs (what is the case for all Japanese's nuclear plants) in a country periodically devastated by tsunamis. Otherwise, building cheaper nuclear plants and to make benefit. Not paying attention to recommendations of seismology specialist who were asking to upgrade security against earthquakes.
Improvidence. Japanese astound us with their spectacular progress in robotic. In Japan, robots know how to ride a bicycle, to talk, to smile. They build humanoid robots who have style, they will probably be sold, as artificial servant dogs, or electronic escort girls, to city dwellers suffering from loneliness. It remembers me a chapter of The Martian Chronicles of Ray Bradburry, that I highly recommend to read or to reread.
But, in Japan, no one have invested in security robots, able to climb upon rubble, but above all build with a lead shielded electronic able to resist against the intense radiation flux. Japan needed to bring them from foreign countries.
We have seen one of these people responsible of this criminal bad management, ''overwhelmed by the emotion'', to shed crocodile tears (but who wouldn't accept to sit nearby machine's operators who dangerously approach reactors to tempt to cool down them). In Japan, political responsible or economic actors, who have ruined hundred of thousand decent people come periodically in front of media for public apologizes. The responsible of a nuclear disaster shed few tears. This replaces the traditional Seppuku, a cold steel suicide.
This video shows arrangement of wastes coming from the running of a boiled water nuclear reactor, those wastes are manipulated from a distance and stored in a water pool, this water playing role of a radiations absorbing shield.
You must understand one thing. In nuclear industry, the results of activities of electricity production, highly radioactive and dangerous to manipulate wastes, are simply stored very close to the reactor, in ordinary water pools. Water is enough to block different radiations. Afterwards, those wastes will be routed to ''reprocessing centers'', like in La Hague, to extract the future fuel for...Fast Breeder reactors. Those wastes are not at all passive and constitute a material as dangerous as the contents of the reactor itself.
The stock ''pool'' of used elements
This pool is situated in the immediate neighborhood of the reactor, for reasons of easy manipulations.
A zoom shot on those ''structures'' regrouping ''pencils'':
60 ''pencils'' per ''assembly'' in Japanese's reactors
Zooming a little more, we can see details on those ''pencils'', who constitute those ''structures''. These are zirconium tubes (also called "gines"), filled with ''fuel pellets'': uranium oxides or, in the case of the ''MOX'', a mixture of uranium oxide and plutonium oxide. If water, in which those structures are immersed, is evaporated, waste heat generated by those structures, stored in compact ranks, is enough to quickly damage zirconium tubes and allow pellets to escape and gather on the bottom of the pool. Unless an explosive phenomenon disperses these products around the reactor.
Here is the source of what follows:
The tank (here, opened) and the ''pool'' are linked by doors, locks acting
Periodically ''the reactor is stopped''. The control bars are raised, which reduces the activity of the reactor at its minimum, which is not zero, because products of fission continue evolving, decomposing while releasing heat (60 megawatts, the tenth of the rated operating regime). The lock insulating the top of the reactor with the stock pool is open. Water invades all available space. Handling of the structures is now operated under water, using the crane and the telescopic arm, either for removing ''worn'' structures or replacing them by ''new'' structures. Anyway, unless a reprocessing industry, like La Hague, take over, the ''worn'' structures will be stocked in a proximity pool, where they continuing to warm water of the ''storage pool of elements consumed and transit for supply of new elements''.
Handling and assembly, under a blanket of water, radiation shielding
Here is a photo showing such a manipulation, taken in a reactor set up in the United States, in Brown Ferry's nuclear power station in Alabama.
Transfer of an used assembly to the storage basin
The ''cattle chute'' name has been chosen because of the resemblance between those bridges and ways which conduct cattle to the place where they will be slaughtered.
This photo is taken by the operator of the crane. Under his feet: the water which protects him from radiations. At a few meters below, we clearly distinguish the blue glow which corresponds to the effect of radiation emitted by ''used'' fuel elements. We can see that it is clearly not passive!!
Here another photograph of a storage basin for American reactor (Alabama), empty, before usage.
Few decades ago I visited an experimental pool reactor Pˇgase installed in Cadarache. Looking through that water, clear, we saw ''all innards of the reactor'', surrounded by a blue glow, located ten meters lower. It was like seeing death in front, the nuclear poison close. Speed of particles emitted was not higher than the speed of light, in the void, but higher than that speed in water, which is more than 200,000 km/s. The ratio 200,000/300,000 = 1,5 corresponds to the water's index of refraction. Particles were then emitted at ''supersonic speed'' towards speed of light in this environment and we saw clearly things that looked like '' shockwaves '', this corresponds to what we call ''Cherenkov radiation''. In an environment other than void, time of propagation of light is expanded because of the absorption-emission time of photons by atoms and molecules. But between two atoms, photons go at 300,000 km/s.
Pˇgase (35 megawatts thermal), nuclear reactor of research and tests, divergence at Cadarache in 1963, it is a atomic pile where tests are made on fuels for gas cooled piles.
The pool of Pˇgase's reactor has been converted in 1980 to store 2,703 containers containing 64 kg of plutonium.
Here are sources of what follows:
Each joint element (see above) weighs 170 kg and contains 60 ''pencils''. The storage pool of the reactor no 3 contained as much as high toxic ''used'' bars than... his core.
Below is a picture broadcasted by the NHK of Japan, which indicates that watering (by sea water) must be done at a height of 22 m.
Watering of Japanese's reactors needs to throw (sea) water at a height of 22 m (source: Japanese TV NHK)
Watering crane, mounted on a moving vehicle
Test of this watering crane
March 22 2011: as reported by a reader, it seems to be a remote beam dump concrete, as indicates this picture that he sent to me (and I thank him):
Seen on the left the concrete truck carrier with its concrete mixer rotating.
Of course, we can use a pole like this to drop down water at a height of 22 m, where cooling can be the most effective. If it used for flooding the reactor under concrete, it would be clearly more serious. This would signify that body cooling of the reactors, or one of them could be destroyed.
We can only hope, for Japanese, that the situation is not so critical that it appears, speaking of nuclear (modulo the fact is that victims of this tsunami amount to 20,000 at this day).
The fact remains that those events make us brutally realize again the risks of nuclear power.