Deadly radiation estimated inside reactor vessel
The operator of the crippled Fukushima Daiichi nuclear plant says its latest estimation of the radiation level inside one of the reactors was extremely high and had the potential to be lethal to a human within a short period of time.
Tokyo Electric Power Company conducted an inspection inside the containment vessel of the plant’s No.2 reactor last month using a remote-controlled camera, as part of a survey to scrap the reactor.
An analysis of the images found that the radiation was up to 530 sieverts per hour at a concrete cylinder supporting the reactor.
The level is enough to be lethal to a human within a short period of time, despite a possible error margin of up to 30 percent.
A survey conducted 1 year after the nuclear accident at a different part inside the same containment vessel logged 73 sieverts per hour.
In the latest estimation inside the vessel, the area near its opening logged 50 sieverts per hour at maximum.
The operator officials say that there are no leaks of gas with radioactive substances from the containment vessel.
Officials suspect that fuel debris; a mixture of nuclear fuel and melted parts of the reactor’s facility, may be emitting strong radiation inside the vessel.
Some molten fuel penetrated the reactor’s bottom and has reached the containment vessel as fuel debris.
The company plans conduct further inspections with a robot. There is a risk that some parts of the grating where the robot will be moving may be damaged by the high heat of the molten fuel.
Record high fatal radiation levels, hole in reactor detected at crippled Fukushima nuclear facility
Record high radiation levels that’s lethal even after brief exposure have been detected at a damaged reactor at the Fukushima power plant in Japan. Specialists also found a hole, likely caused by melted nuclear fuel.
Radiation levels of up to 530 Sieverts per hour were detected inside an inactive Reactor 2 at the Fukushima Daiichi nuclear complex damaged during the 2011 earthquake and tsunami catastrophe, Japanese media reported on Thursday citing the plant operator, Tokyo Electric Power Company (TEPCO).
A dose of about 8 Sieverts is considered incurable and fatal.
A hole of no less than one square meter in size has also been discovered beneath the reactor’s pressure vessel, TEPCO said. According to researchers, the apparent opening in the metal grating of one of three reactors that had melted down in 2011, is believed to be have been caused by melted nuclear fuel that fell through the vessel.
The iron scaffolding has a melting point of 1500 degrees, TEPCO said, explaining that there is a possibility the fuel debris has fallen onto it and burnt the hole. Such fuel debris have been discovered on equipment at the bottom of the pressure vessel just above the hole, it added.
The latest findings were released after a recent camera probe inside the reactor, TEPCO said. Using a remote-controlled camera fitted on a long pipe, scientists managed to get images of hard-to-reach places where residual nuclear material remained. The substance there is so toxic that even specially-made robots designed to probe the underwater depths beneath the power plant have previously crumbled and shut down.
However, TEPCO still plans to launch further more detailed assessments at the damaged nuclear facility with the help of self-propelled robots.
Earlier this week, hopes for a more efficient cleanup at Fukushima were high, as the plant operator announced a portion of nuclear fuel debris responsible for a lot of the lingering contamination from six years ago may have finally been found.