by Pierre-Henri Lab
Translated Wednesday 16 March 2011, by Henry Crapoand reviewed by
In Japan, the situation is getting out of control.
According to specialists, the situation at the nuclear power plant in Fukushima is very serious. The failure of the enclosure insulating reactor #2 increases the threat of a massive release of radioactivity into the atmosphere.
The situation, yesterday in Japan, has degenerated to a very high degree. To the point that catastrophe seems inevitable. Classed initially at Level 4 on the INES  scale, the accident provoked on Saturday by the earthquake and tsunami at the nuclear plant of Fukushima has been reevaluated at Level 6, the French nuclear safety authority (ASN ) announced. Specialists no longer exclude the possibility that the seriousness reach Level 7, that of the catastrophe at Tchernobyl in 1986.
At the power plant in Fukushima, the situation has apparently escaped the control by Japanese authorities and by the operator Tepco, which has encountered difficulties to maintain control of four of the six reactors. The situation in reactors #1 and #3 has apparently not much changed since Monday. Their cooling systems remain inoperative, and the operators continue to try to cool the reactors by injection of sea water.
Fires have Provoked the Release of Radioactive Material
Serious problems have arisen in reactor #4, in which, up until now, no serious failure had been reported. According to information published yesterday by the ASN and confirmed by the International Atomic Energy Agency (IAEA), "a fire started yesterday at about 9h30 local time, at the level of the spent fuel pool". Rescue workers managed to extinguish the fire toward noon, but it had already provoked the emission of radioactive material. "Levels of up to 400 millisievert per hour were recorded on site", relates the AIEA. Medical observations note the increase in the number of cancers once the human body receives a dose of 100 millisievert per hour. The Japanese press agency reports that the level of radioactivity in the control room of the reactor has reached a level so high that engineers can no longer carry out normal work. In order to try to preserve their health, "they must not remain there for too long; they should make short trips to the control room, but supervise the effort from other locations."
Two Successive Explosions
"The main preoccupation at present is for reactor #2", writes the ASN in a communiqué. The Authority confirms that a partial fusion of the reactor has indeed taken place. In order to prevent the phenomenon from spreading, "the operating company continues to try to cool the core of the reactor by injecting sea water", but "they are having difficulties to carry out this task because of the blockage of a relief valve on the container".
Two explosions occurred one after the other at 6h10 and at 10h (local time), "probably caused by disintegration of the confinement barrier" of reactor #2, to such a degree that "it is no longer properly sealed", assures the president of the ASN, André-Claude Lacoste. This failure of the sealing is particularly worrisome. The confinement barrier constitutes the final bulwark between the reactor and the environment. If the employees of Temco do not manage sufficiently to cool the reactor, to prevent the fuel in fusion from penetrating the steel envelope, its failure renders possible a contamination of the atmosphere, the consequences of which would be considerable.
No Consequences for Health have been Evoked
The quantity of radioactivity accidentally released by explosions around the reactors, or that released in a controlled manner in order to prevent overly high pressures in the surrounding containers, have not been made public. Nevertheless, levels of radioactivity higher than normal have been measured in Tokyo, which is situated 250 kilometers from the reactors in Fukushima. According to the city government, these levels reached 0.809 millisievert per hour during the morning. In the afternoon, they dropped to 0.075 millisievert per hour. The normal level is about 0.035 to 0.036 microsievert per hour.
No health consequences have yet been evoked, but concern is real for the outcome for the 150 workers at the nuclear plant, who are trying to head off the worst.