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Press Release (Jul 29,2011)
Primary evaluation of internal exposures in March and April (for those who remain un-evaluated)
We have been sequentially evaluated exposure doses of workers at Fukushima 
Daiichi Nuclear Power Station in two categories as below:

(1) primary and secondary evaluation of internal exposures (those who have 
    exceeded 20mSv at the primary evaluation will have more detailed 
    secondary one)
(2) external exposures

We have submitted interim reports to Ministry of Health, Labor and Welfare 
when each due date comes and we have announced them on June 13, 20, 30, 
July 13, and 20.

Today, we announce that we reported the following (details attached) to 
Ministry of Health, Labor and Welfare.

(1) Primary evaluation of internal exposures in March and April (for those 
    who have remained evaluated) 
    - The number of workers who have not finished the primary evaluation is 
      440, decreasing from 1,546 (as of July 13).
    - The result of primary evaluation this time is as follows:
        Over 100mSv :           1 person(112.5mSv)
        Over 50mSv to 100mSv:   15 persons
        Over 20mSv to 50mSv:    17 persons
(2) External exposures for the new entrants to the controlled access zone
    - The number of workers who newly entered the zone in June was 2,308. 
      The maximum of external exposures was 38.66 mSv.

We are planning to submit reports as follows:
- Primary evaluation of internal exposures for those who worked in May 
  (August 10)
- Secondary evaluation for workers with "over 20mSv to 50mSv", including 
  those newly identified (August 10)
- Primary evaluation of internal exposures in March and April for those who, 
  as of today, remained un-evaluated (August 10)

*1 primary evaluation of internal exposure doses
A temporary evaluation based on the assumption that each worker absorbed the 
entire volume of radioactive substances at the first date of work (if the 
worker began work from the outset, on March 12) resulting in the maximum 
figures of doses.

*2 secondary evaluation of internal exposure doses
As opposed to the primary evaluation, the reevaluated figures such as 
adjusting the date of absorption per each person's behavioral survey and 
conducting detailed measurement by JAEA.

attachment:
Enhancing controls of internal exposures at Fukushima Daiichi Nuclear Power 
Station

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