[ RadSafe ] Hard Numbers

Jeff Terry terryj at iit.edu
Sun Mar 20 23:22:17 CDT 2011

From NISA, 


Tokyo Electric Power Co., at around 12:00 March 19th, took the sample of dust in the air for the first time using a monitoring car in front of the main building in Fukushima Dai-ichi Nuclear Power Station and carried out Radioactive Nuclide Analysis.

Major radioactive nuclides detected   Concentration of radioactive nuclide (Bq/cm3)  Allowable concentration of radioactive nuclide in the air for radiation workers (Bq/cm3)
Iodine-131   5.940 x 10-3  1.0 x 10-3
Iodine-132   0.220 x 10-2  7.0 x 10-2
Iodine-133  0.035 x 10-3  5.0 x 10-3
Cesium-134  0.022 x 10-3  2.0 x 10-3 
Cesium-137  0.024 x 10-3  3.0 x 10-3

<Exposure of residents> (1) Including the about 60 evacuees from Futaba Public Welfare Hospital to
Nihonmatsu City Fukushima Gender Equality Centre, as the result of measurement of 133 persons at the Centre, 23 persons counted more than 13,000 cpm were decontaminated.
(2) The 35 residents transferred from Futaba Public Welfare Hospital to Kawamata Town Saiseikai Kawamata Hospital by private bus arranged by Fukushima Prefecture were judged to be not contaminated by the Prefectural Response Centre.
(3) As for the about 100 residents in Futaba Town evacuated by bus, the results of measurement for 9 of the 100 residents were as follows. The evacuees, moving outside the Prefecture (Miyagi Prefecture), were divided into two groups, which joined later to Nihonmatsu City Fukushima Gender Equality Centre.
*(These results were measured without shoes, though the first measurement exceeded 100,000cpm)
(4) The screening was started at the Off site Centre in Okuma Town from March 12th to 15th. 162 people received examination until now. At the beginning, the reference value was set at 6,000cpm. 110 people were at the level below 6,000 cpm and 41 people were at the level of 6,000 cpm or more. When the reference value was increased to 13,000 cpm afterward, 8 people were at the level below 13,000 cpm and 3 people are at the level of 13,000 cpm or more.
The 5 out of 162 people examined were transported to hospital after
No. of Counts No. of Persons
18,000cpm                   1
30,000-36,000cpm     1
40,000cpm                   1
little less than 40,000cpm*      1
very small counts    5
15being decontaminated.
(5) The Fukushima Prefecture carried out the evacuation of patients and personnel of the hospitals located within 10km area. The screening of all the members showed that 3 persons have the high counting rate. These members were transported to the secondary medical institute of exposure. As a result of the screening on 60 fire fighting personnel involved in the transportation activities, the radioactivity higher than twice of the back ground was detected on 3 members. Therefore, all the 60 members were decontaminated.
<Exposure of workers> (1) As for the 18 workers conducting operations in Fukushima Dai-ichi NPS,
results of measurements are as follows; One worker: At the level of exposure as 106.3 mSv, no risk of internal
exposure and no medical treatment required. Other workers: At the level of no risk for health but concrete numerical
value is unknown. (2) As for the 7 people working at the time of explosion at around the Unit 3
of Fukushima Dai-ichi NPS who were injured and conscious, 6 out of 7 people were decontaminated by an industrial doctor of the clinic in Fukushima Dai-ni NPS, and confirmed to have no risk. The other one is having a medical treatment at the clinic after decontaminated.
<Others> (1) Fukushima Prefecture has started the screening from 13 March. It is
carried out by rotating the evacuation sites and at the 12 places (set up permanently) such as health offices. The results of screening are being totalled up.
(2)5 members of Self-Defence Force who worked for water supply in Fukushima Dai-ichi NPS were exposed. After the work (March 12th), 30,000 cpm was counted by the measurement at Off site Centre. The counts after decontamination were between 5,000 and 10,000 cpm. One member was transferred to National Institute of Radiological Science. No other exposure of the Self-Defence Force member was confirmed at the Ministry of Defence.
(3) As for policeman, the decontaminations of two policemen were confirmed by the National Police Agency. Nothing unusual was reported.

Jeff Terry
Asst. Professor of Physics
Life Science Bldg Rm 166
Illinois Institute of Technology
3101 S. Dearborn St. 
Chicago IL 60616
terryj at iit.edu

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