Tokyo: 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 stabilise the plant which has been leaking radiation for more than two months.
Workers in protective gear 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 blow off the No 3 reactor building’s roof.
Tokyo Electric Power Co is keen to proceed with work in the reactor buildings to prevent further hydrogen blasts and put in place a sustainable cooling system that will stabilise the reactors, although high radiation levels have hindered their efforts.
The utility was delivered a further setback this week when it learned of leaks in the three reactors’ pressure vessels, although it has vowed to stick to a timetable, set in April, for bringing the Fukushima Daiichi reactors to a stable state by January, despite scepticism from a number of experts.
Each of the two Tepco employees that entered the No 3 reactor building on Wednesday evening was exposed to less than 3 millisieverts of radiation during their 10-minute stay, compared with the government-set upper limit of 250 millisieverts per worker for the duration of the Fukushima stabilisation project.
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.
“Workers being able to enter the reactors is perhaps the biggest improvement (since the Tepco announcement of its timetable for stabilising the plant),” said a nuclear energy professor who declined to be named.
“They have made the ventilation of the reactor building possible and it also enables Tepco to install heat exchangers and pumps.”
The prolonged nuclear crisis has sparked a national debate over nuclear safety and boosted support for anti-nuclear groups’ calls to ditch plans, unveiled last year, to build nine new reactors by 2020 and at least 14 by 2030.
On Thursday, National Strategy Minister Koichiro Gemba said it would be impossible to go ahead with building all 14 reactors, Kyodo news agency reported.
Prime Minister Naoto Kan last week called for a clean-slate review of Japan’s nuclear policy, which had envisaged more than 50 percent of the total electricity supply coming from nuclear power by 2030, although he has since sidestepped the question of how big a role atomic power will play in the future.
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 on Friday.
More than 90,000 tonnes of radioactive water has collected in basements and trenches in and around the reactor and turbine buildings at the plant, as the utility poured water into reactors to cool their fuel rods after the disaster disabled their cooling systems, creating a risk of seepage into ground water and the ocean.
The rectangular steel structure will be able to hold 10,000 tonnes of water, about enough to fill four Olympic-sized swimming pools. Agencies