As part of emergency precautions being taken at Fukushima Daiichi Nuclear
Power Station, we have been evaluating the internal exposure dose of each
worker*. On May 30, 2011, the survey revealed that the levels of internal
radioactivity (iodine 131) present in thyroids of the two TEPCO male
employees were higher than normal level and we have disclosed that fact.
Subsequently those two TEPCO employees were to receive evaluation work
administered by the National Institute of Radiological Sciences (NIRS:
Independent Administrative Corporation). (Previously announced)
Today we have received the report of evaluation result from NIRS and
finished evaluation of internal exposure based on the report as follows.
As a result of evaluation, it was confirmed that exposure dose of two
employees exceeded the 250 mSv limit in case of emergency. It was also
confirmed that there were no impact on their health condition as a result
of medical examination.
<Exposure dose of those two employees>
A:678.08 mSv (external exposure: 88.08 mSv, internal exposure 590 mSv)
B:643.07 mSv (external exposure: 103.07 mSv, internal exposure 540 mSv)
*Above amount does not include the exposure dose from the stay in the main
anti earthquake resistant building and from the transfer in the site as
those exposures are still under evaluation. These will be added once the
evaluation is done.
JAEA yesterday reported us that during the evaluation work of internal
exposure dose of TEPCO employees in charge of emergency work the level of
internal radioactivity (iodine 131) present in thyroids of a TEPCO male
employee was higher than normal level. The employee will have medical
examination by NIRS and his internal exposure will be evaluated and
determined* with the help of NIRS advice.
*Determining exposure dose
Work to evaluate and add the exposure dose during the work and the stay
in the main anti earthquake building in addition to internal exposure
levels of the committed dose (exposure spanning a 50-year period from