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Fukushima Nuclear Crisis, Radiation Consequences

An interesting publication is released from Japan: “The time variation of dose rate artificially increased by the Fukushima nuclear crisis.”

This is of great interest to everyone anxious to know about the radiation consequences of the incident. To understand the results in perspective, another document "Nuclear radiation and Health Effects” is also attached. This document also provides exposures during Chernobyl accident. Because the units of radiation are in SI units, following conversion Table (may not be exact) but is useful for those of us who are familiar with US units.

Conversions from SI units to US units

Radiation dose (or exposure) rates:

1 µSv/h = 1 µGy/h = 100 µrad/h = 115 µR/h

Normal BG =0 .08 µGy/h = 9.2 µR/h

High Dose rates in Japan = 36 µGy/h = 4140 µR/h

Dose and Exposures

1 Sv is equal to 1 Gy (for gamma radiation)

1 Gy = 100 rad = 115 R

High Exposures in Japan =68 mSv = 68 mGy = 7820 mR

These can be compared with the permissible exposures.

The maximum annual dose allowed for radiation workers is 20 mSv/yr, though in practice, doses are usually kept well below this level. However, higher one time exposures are permitted in unusual cases for emergency work. For more information, please see the document attached.