106Ru
36,400 Ci
144Ce
17,200 Ci
137 Cs
35,800
90Sr
12,300
3H
31,500
91y i.e.
4,400
95Zr
18,000
103Ru
830
95Nb
17,300
89Sr
390
From 1969 to 1976 this sums up to an overall 500,000 Ci of caesium-137 and over
100,000 Ci of caesium-134. Added to these are alpha-emitters like plutonium-239.
The permissible amount for these was raised to 6000 Ci per year in 1970 and in 1974,
4560 Ci equivalent to 76% of the amount permitted were released into the sea.
The emissions from Wind scale are the reason why in the northwestern part of the
North Sea 5-10 pC ill of caesium-137 are being measured, far more than the 0.20.3 pCi/1 basic level in the surface waters originating from radioactive fall-out
(Fig. 57). The emissions from La Hague are the reason why in the southeastern part
of the North Sea 0.7-1.0 pCi/1 of caesium-137 are being measured. Since 1975, however, only very low quantities of caesium-l 37 are being discharged into the water and
since 1977 the figures measured in the North Sea have decreased accordingly (Deutsches Hydrographisches Institut 1978).
According to calculations of the International Atomic Energy Agency (IAEA) concentrations of up to 900 pCi/1 of caesium-137 in the ocean water can be tolerated.
Therefore the caesium-137 concentrations measured in the North Sea are not injurious to health. However, the exposure is of course higher directly near the processing
plants: in the area of Windscale 100 pCi/I, and directly in the emission zone 10002000 pCi/1. The concentration levels in the organisms are also accordingly high
(Table 24). Obviously plutonium is not that easily spread over wide areas by water
masses. Figures from the North Sea are not too different from those of the Atlantic
Ocean (Murray and Kautsky 1977).
In the future increasingly more spent-fuel elements will be produced and new reprocessing facilities are being planned in many countries. Here it should be possible, to
keep the concentration levels of radioactivity in the waste water lower than at Windscale and La Hague, by way ofirnproved cleansing processes. More reprocessing, however, means more transporting, also across the sea. It is estimated that in 1990, 50 t
of plutonium will constantly be en route between nuclear reactors and reprocessing
facilities. This figure may be wrong, just like all the other forecasts about the further
development of nuclear energy, but it is certain that accidents will occur during transportation whereby plutonium will enter the environment.
During operation, too, nuclear reactors emit radioactivity into the surroundings in
the form of tritium, krypton-85, carbon-14, caesium-137 and caesium-134, strontium-90, iodine-131 and cobalt-60. The amounts of radioactivity in waste water is,
however, not very high (Table 22). The nuclear power plant Unterweser at Esenshamm, Germany, has permission to emit 950 Ci of tritium and 2 Ci of dissolved fission- and activation-products into the river Weser, per year.
The emissions from nuclear-powered merchant vessels are also low. The German
freighter "Otto Hahn" was allowed to emit 2 Ci of radioactive isotopes per month into
the seawater, but from 1974-1976 the overall emission only amounted to 2-3 Ci
per year. Concerning atomic-powered war-ships, of which there are some hundred,
110
36,400 Ci
144Ce
17,200 Ci
137 Cs
35,800
90Sr
12,300
3H
31,500
91y i.e.
4,400
95Zr
18,000
103Ru
830
95Nb
17,300
89Sr
390
From 1969 to 1976 this sums up to an overall 500,000 Ci of caesium-137 and over
100,000 Ci of caesium-134. Added to these are alpha-emitters like plutonium-239.
The permissible amount for these was raised to 6000 Ci per year in 1970 and in 1974,
4560 Ci equivalent to 76% of the amount permitted were released into the sea.
The emissions from Wind scale are the reason why in the northwestern part of the
North Sea 5-10 pC ill of caesium-137 are being measured, far more than the 0.20.3 pCi/1 basic level in the surface waters originating from radioactive fall-out
(Fig. 57). The emissions from La Hague are the reason why in the southeastern part
of the North Sea 0.7-1.0 pCi/1 of caesium-137 are being measured. Since 1975, however, only very low quantities of caesium-l 37 are being discharged into the water and
since 1977 the figures measured in the North Sea have decreased accordingly (Deutsches Hydrographisches Institut 1978).
According to calculations of the International Atomic Energy Agency (IAEA) concentrations of up to 900 pCi/1 of caesium-137 in the ocean water can be tolerated.
Therefore the caesium-137 concentrations measured in the North Sea are not injurious to health. However, the exposure is of course higher directly near the processing
plants: in the area of Windscale 100 pCi/I, and directly in the emission zone 10002000 pCi/1. The concentration levels in the organisms are also accordingly high
(Table 24). Obviously plutonium is not that easily spread over wide areas by water
masses. Figures from the North Sea are not too different from those of the Atlantic
Ocean (Murray and Kautsky 1977).
In the future increasingly more spent-fuel elements will be produced and new reprocessing facilities are being planned in many countries. Here it should be possible, to
keep the concentration levels of radioactivity in the waste water lower than at Windscale and La Hague, by way ofirnproved cleansing processes. More reprocessing, however, means more transporting, also across the sea. It is estimated that in 1990, 50 t
of plutonium will constantly be en route between nuclear reactors and reprocessing
facilities. This figure may be wrong, just like all the other forecasts about the further
development of nuclear energy, but it is certain that accidents will occur during transportation whereby plutonium will enter the environment.
During operation, too, nuclear reactors emit radioactivity into the surroundings in
the form of tritium, krypton-85, carbon-14, caesium-137 and caesium-134, strontium-90, iodine-131 and cobalt-60. The amounts of radioactivity in waste water is,
however, not very high (Table 22). The nuclear power plant Unterweser at Esenshamm, Germany, has permission to emit 950 Ci of tritium and 2 Ci of dissolved fission- and activation-products into the river Weser, per year.
The emissions from nuclear-powered merchant vessels are also low. The German
freighter "Otto Hahn" was allowed to emit 2 Ci of radioactive isotopes per month into
the seawater, but from 1974-1976 the overall emission only amounted to 2-3 Ci
per year. Concerning atomic-powered war-ships, of which there are some hundred,
110