An accelerated schedule for spent fuel removal, high thyroid doses among workers and more revelations from the early days of the crisis marked the news from Fukushima Daiichi this week.
Recent developments at the Japanese nuclear plant blacked out following last year's earthquake and tsunami include:
Unit 4 Spent Fuel to Come Out Earlier
Tokyo Electric Power Co. plans to finish removing fuel assemblies from unit 4 a year earlier than planned. All 1,535 assemblies were in the unit's spent fuel pool at the time of the earthquake and subsequent hydrogen explosions that damaged the reactor's shield building. On Monday the utility revealed plans to begin the removal operation in November of next year, Kyodo reported, a month earlier than originally planned. Work should finish in 2014 on a timeline accelerated partly by the success of debris removal at the SFP to date.
High Thyroid Doses Found Among Fukushima Workers
Among tests of 522 Fukushima workers suspected of receiving high whole-body internal doses, 163 showed thyroid doses greater than 200 millisieverts. The Asahi Shimbun reported that a forthcoming report by the World Health Organization using the data from TEPCO also will indicate two workers had thyroid doses in excess of 10,000 millisieverts. One of them, a man in his thirties that TEPCO said did not report negative health effects, had a thyroid dose of 11,800 millisieverts, with a whole-body external and internal dose of 678.8 millisieverts. High doses in the thyroid are not as dangerous as high whole-body doses but can increase the risk of cancer in that organ.
Plant Chief Made Repeated Pleas, Warnings to TEPCO Headquarters
Japanese reporters witnessed Fukushima Daiichi's plant manager becoming increasingly desperate for manpower and monitoring equipment in another batch of crisis teleconference footage released by TEPCO. Media representatives were allowed to see the teleconferences recorded March 16 to March 23 and March 30 to April 6, 2011, but were forbidden from taking their own video or audio recordings. Some of the most salient moments observed by Asahi Shimbun reporters came in plant General Manager Masao Yoshida's conferences with TEPCO executives in Tokyo. In one exchange, he pleaded for more men and bluntly refused to send his workers – who at that point had grappled with the crisis non-stop for eight days – back into high-radiation areas, noting that all plant workers were approaching or had exceeded the 200-millisievert dose limit.
Two weeks later, Yoshida again showed his frustration with TEPCO's leadership as contaminated water flooded four units at the plant and threatened to overflow into the sea. His request for cameras to remotely monitor water in turbine halls was deferred until after workers discovered a leak April 2 in a nearly overflowing outdoor pit, the Asahi reported. The leak released an estimated 520 cubic meters of highly radioactive water into the ocean before crews sealed it off. On March 30, three days after rising water was detected in the pit, Yoshida told TEPCO headquarters, "I can't help but feel that we are idly waiting for death."