Reuters – Workers wearing protective suits enter the Tokyo Electric Power Co. (TEPCO)'s Fukushima Daiichi nuclear … TOKYO (Reuters) – Japanese workers have entered the last of three reactor buildings hit by nuclear fuel meltdowns at the tsunami-crippled Fukushima plant, operator Tokyo Electric said on Thursday, as it moves to stabilize a facility that has been leaking radiation for more than two months.
Workers in protective gear, including oxygen tanks, began inspections in the No. 3 reactor building, which had not been entered since the March 11 earthquake and tsunami triggered fuel meltdowns and a hydrogen explosion that blew off the No. 3 reactor building's roof.
Tokyo Electric Power Co is pushing ahead with work in the reactor buildings to install a cooling system that will stabilize the reactors, although high radiation levels and difficult working conditions have hindered its efforts.
One of the workers who on Wednesday entered the No. 2 reactor building, where temperatures have reached 40 degrees Celsius (104 degrees Fahrenheit), was treated for an apparent heat stroke, the utility said.
Last week, Tepco said it believed that large leaks had developed in the three reactors' pressure vessels, although it has vowed to stick to a timetable for bringing the Fukushima Daiichi reactors to a stable state by January.
Some nuclear experts view that target as a stretch, especially since the utility is also struggling to contain a growing pool of radioactive water at the plant.
The two Tepco employees that entered the No.3 reactor building on Wednesday evening were exposed to less than 3 millisieverts of radiation during their 10-minute stay, compared with the government-set limit of 250 millisieverts per worker per year.
The electric utility, also known as Tepco, has already sent workers into the buildings that house the No.1 and No.2 reactors, the two other units in operation at the six-reactor plant at the time of the massive quake and tsunami.
CONTAMINATED WATER
Separately, Tepco released dramatic new images of the 14-meter (46-foot) tsunami as it began to break against the seawall, illustrating how the Fukushima plant's defenses were overwhelmed by the disaster.
Japan has promised a full and independent account of how the worst nuclear crisis since Chernobyl developed and whether mistakes were made in the initial response.
One unresolved question has been whether the Fukushima reactors were damaged by the earthquake before the tsunami hit the plant and took out its backup power supply.
Tokyo Electric said on Thursday that a radiation alarm connected to a sensor outside the plant had sounded minutes before the tsunami hit but officials said a second sensor at the same spot had shown a normal reading and concluded that the first sensor was broken.
"It's our judgment that there was not a release of radiation (at that time)," said Tepco spokesman Junichi Matsumoto.
Tokyo Electric also said a giant floating steel structure that will store some of the plant's massive volume of contaminated water would arrive at the complex this weekend.
About 90,000 tonnes of radioactive water has collected in basements and trenches in and around the reactor buildings, as the utility poured water into reactors to cool their fuel rods after the disaster disabled their cooling systems. Tepco faces a major challenge in preventing that water from seeping into ground water and the ocean.
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