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Press Releases 2014

Press Release (Mar 25, 2014)Reevaluation of Internal Exposure Doses of TEPCO Workers During Emergency Work at Fukushima Daiichi Nuclear Power Station

TEPCO has been evaluating the exposure dose of workers at Fukushima Daiichi Nuclear Power Station by evaluating the exposure dose of employees and collecting the evaluation results obtained from various subcontractors. The results of these evaluations are submitted to the Ministry of Health, Labor and Welfare (MHLW) at the end of each month and also announced publicly.

These evaluation results of internal exposure doses indicated that results obtained through calculation and evaluations based on data owned by TEPCO differed to results (adopted values) obtained through evaluation based on detailed surveys conducted by each cooperative company. In this light, MHLW conducted reconfirmation work on the validity of this data and the methods used for evaluating internal exposure doses, and TEPCO received revised data from subcontracted companies based on the revision instructions provided to them from MHLW. Accordingly, TEPCO submitted exposure dose distribution tables updated with this revised data to MHLW on July 5, 2013.

(Previously announced on July 5, 2013)

TEPCO subsequently received a request from MHLW to categorize internal exposure dose calculation processes by the evaluation method used for each standard method of internal exposure dose evaluation in order to evaluate exposure as part of epidemiological studies of the health effects on the thyroid gland being conducted by MHLW. TEPCO began classification work and reported to MHLW on January 31 this year that nine employees had conducted internal exposure dose evaluations that were not in accordance with standard methods.

On March 26, 2014, MHLW instructed TEPCO and each cooperating company with confirmation work to recheck whether or not such incidents had occurred again. The instructions stated to reconfirm internal exposure dose evaluation details for all employees working in the 1F building following the explosion of Reactor 1 in March 2011 through to the end of April 2011, in addition to workers targeted in the previous report.

The reconfirmation work on internal exposure dose was completed today (March 25, 2014), and TEPCO hereby announces that a report on TEPCO employees was submitted to MHLW.

There were 24 TEPCO employees that were required to revise their internal exposure dose. These TEPCO employees are those whose internal exposure dose evaluation was finalized at a relatively early stage. In accordance with these instructions from MHLW, the estimated date radioactive material intake of these employees was revised, and the evaluation method was also revised.

No significant intake of radioactive substances has been observed since October 2011, however if any significant intake is identified in the future, WBC will be conduct measures immediately to evaluate the internal exposure dose and instructions from MHLW will be confirmed again. Cooperating companies will be requested to cooperate with evaluations as they did previously to further enhance radiation control conducted at Fukushima Daiichi Nuclear Power Station.

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Reevaluation of Internal Exposure Doses of TEPCO Workers During Emergency Work at Fukushima Daiichi Nuclear Power Station(PDF 41.6KB)PDF

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