A powerful radiation within the "Fukushima-1" in the literal sense of the robot cleaner roasts
The cleaning robot was sent into the reactor №2 to check and then clear the passage for the other robot inside a damaged nuclear power station
Remotely controlled robot designed for research and cleaning up the damaged reactors at the Japanese nuclear power plant "Fukushima -1" had to urgently evacuate after its navigation camera suddenly darkened as a result of exposure to an incredibly powerful radiation levels. The failure of the mission is tempting to think that the radiation level inside the reactor plant is much higher than it was reported last week. In addition, it means that even robots need plenty of time to deal with a local mess.
In the last week, it was reported that available for the reactor containment №2 level of radioactivity has reached a catastrophic 530 Sv / h - enough to kill a person within a few seconds. However, some officials of the Japanese government to cast doubt on these statements, as the Tokyo Electric Power Company Holding (TEPCO), a company engaged in removing the debris at the "Fukushima-1" is used for this purpose interface robot camera, with which she explores the territory, and did not conduct the necessary measurements directly using Geiger counters and dosimeters other.
But, as it turned out, the original estimates were even lower than the real picture of today. This is due, probably, to the fact that TEPCO robot is getting closer to the molten nuclear fuel. Near the accumulation of spent fuel, as a rule, always more increased radiation background.
dam zone near the reactor №2 plant "Fukushima-1". Red marker marked the last area of research of the robot cleaner
The other day, remotely controlled robot had to quickly pull out after just a couple hours of work inside the damaged reactor began to refuse his surveillance camera. If you believe the reports of TEPCO, the radiation level at the time was around 650 Sv / h, which is already on the 120 Sv larger than said reports last month (though in the new reports and indicated the possibility of error of 30 per cent). The robot itself designed with the ability to operate at the level of accumulated radiation 1000 Sv, which probably did not help his cell, given that just a few hours after the start of it out of order. This may mean that the molten radioactive fuel leaked out of his tank is still in the crash of 2011 and may be somewhere in the vicinity of the final point of the robot stay.
It is important to bear in mind that the radiation is stored only within the station, and, fortunately, does not affect the regions located near the station. In addition, there is no indication that there is some leakage of radioactive fuel outside the station. The effects of radiation on air and is located next to the ocean is also not observed. In addition, no marked increase in radiation levels and the inside station. Its level in the testimony TEPCO becomes higher because the robot is close to the main light source, that is the most radioactive fuel. Previous level the highest point in 73 Sv / h has been noticed in 2012 and at a remote distance from the epicenter. A few days ago TEPCO sent a robot into the reactor №2 to conduct research and prepare a place for further solving the problem. It was the first time since the earthquake and tsunami that took place 6 years ago and caused the disaster at the "Fukushima-1", when the robot is entered directly in the reactor itself. His task was clearing a thick layer of radioactive waste from molten and solidified paint and pieces of insulation cables, pressurized chamber, which contains the reactor core. TEPCO is trying to clear the way for the other robot, which will need to do further work. The second robot, called "Scorpion", will have to carry out measurements of the radiation level and temperature inside the reactor, and to assess the state of the reactor and remain there radiative fuel residues.
However, before this happens, you need to clear the passage. TEPCO cleaning robot, equipped with a powerful hydrant and a brush, to date, been able to clear only part of the way to the place, which the company wants to further explore. The machine has cleared a few meters of sediment from the burned debris located near the outer part of the skin of the primary reactor containment vessel, but could not go further, as these deposits proved to be too strong for cleaning. With each centimeter catatonic black-gray mass of radioactive fuel, the outer skin and other parts become thicker and thicker. After a couple of hours from the start of the work image, obtained with the robot camera, it has deteriorated significantly, pointing to the impending catastrophic failure. Its operators adopted an emergency decision to end the mission, until they completely lost control of the car.
The molten lattice inside the reactor №2. Most likely, damage caused by the falling down of the molten radioactive fuel
TEPCO is now most worried about the fact that "Scorpion" will not be able to get to the desired point of destination for the reactor shell and, like its predecessor, can not work for a long time in such conditions (the second robot is designed with the possibility of working at 1000 Sv). Extreme levels of radiation can cause TEPCO to review the strategy for parsing debris using robots and turn our attention to the radioactive fuel. In general, the radiation of cleaning up operation is only in the initial stage. The overall level of works may require decades. As long as TEPCO did not establish the exact location of the radioactive fuel and do not know the exact condition and possible level of structural damage in each of the three reactors of the station, clean fuel and eventually dismantle the station will not work.