Radioactive Releases from Nuclear Power Plants During Normal Operation - The Risks of Nuclear Energy Technology - page 84

Table 4.3 Mean effective
radiation dose to the
population from natural
background radiation in the
Federal Republic of Germany
during the year 2008 [ 12 , 13 ]

Mean effective dose
1. Radiation exposure from natural sources mSv/year

1.1 Cosmic radiation (at sea level) ~0.3

1.2 External terrestrial radiation ~0.4

Outdoors (5 h/day) ~0.1

Indoors (19 h/day) ~0.3

1.3 Inhalation of radon and its progeny ~1.1

Outdoors (5 h/day) ~0.2

Indoors (19 h/day) ~0.9

1.4 Ingestion of natural radioactive substances ~0.3

Total natural background radiation ~2.1

4.4 Radiation Exposure from Man-Made Sources

Table 4.4 shows data for the radioactive exposure of man-made radioactivity
sources. These man-made radioactive exposures sum up to 1.9 mSv/year [ 12 , 13 ].

4.4.1 Nuclear Weapons Tests

Numerous atmospheric nuclear weapons tests were carried out from 1945 to 1980,
but since 1981 only underground tests have been performed. The general level of
environmental radioactivity due to former tests in the atmosphere has steadily
decreased since the Comprehensive Nuclear Test-Ban Treaty from 1964. At present
its contribution to the total of human radiation exposure is less than 0.01 mSv/year
[ 12 , 13 ].

4.4.2 Chernobyl Reactor Accident

In April 1986, a reactor accident occurred in the Chernobyl nuclear power plant
which has had serious consequences in Europe so far. In the days following that
accident, large amounts of radionuclides were released into the atmosphere and
distributed all over Europe. In 2008, the associated mean effective dose in Germany
was less than, e.g. 0.012 mSv/year. It amounts to less than 1 % of the natural
background radiation exposure. About 90 % of this radiation is caused by Cs-137
deposited on the ground. Locally also higher exposure values were found. In
addition, higher concentrations of radioactive isotopes were found in mushrooms
and wild animals [ 12 , 13 ].