Accidental Releases
Accidents resulting in direct radioactive releases to
the sea are not well known as most of them are
connected to wreckage of submarines. Eight nuclear
submarines with nuclear weapons have been reported lost at sea, two US and six former USSR. The
last known USSR wreck was the submarine Komsomolets which sank in the Norwegian Sea southwest of Bear Island, on 7 April 1989. The activity
content in the wreck is estimated by Russian authorities to be 1.55–2.8 PBq
90 Sr and 2.03–3 PBq
137 Cs and the two nuclear warheads on board may
contain about 16 TBq
239,240
Pu equivalent to 6–7 kg
plutonium. Other estimates indicate that each warhead may contain 10 kg of highly enriched uranium
or 4–5 kg plutonium.
On August 12th 2000, the Russian nuclear submarine Kursk sank at a depth of 108 meters in the
Barents Sea north of the Kola peninsula. Vigorous
explosions in the submarine’s torpedo-chambers
caused the wreckage where 118 crew-members were
entrapped and lost their lives. Kursk, and Oscar II
attack submarine, was commissioned in 1995 and
was powered by two pressurized water reactors.
Kursk had no nuclear weapons on board. Measurements close to the wreck in the weeks after the
wreckage showed no radioactive contamination indicating that the primary cooling-systems were not
damaged in the accident. A rough inventory calculation estimates that the reactors at present contain
about 56 000 TBq. Russian authorities are planning
for a salvage operation where the submarine or part
of the submarine will be lifted from the water and
transported to land. Both a possible salvage operation or to leave the wreck where it is will be create a
demand for monitoring as the location of the wreck
is within important fishing grounds.
The wreckage of Komsomolets in 1989 and the
attempts to raise money for an internationally financed Russian led salvage operation became very
public. The Russian explanation for the intensive
attempts of financing the salvage was said to be the
potential for radioactive pollution. The wreck of the
submarine is, however, located at a depth of 1658 m
and possible leaching of radionuclides from the
wreck will, due to the hydrography of the area,
hardly have any vertical migration and radioactive
components will spread along the isopycnic surfaces
gradually dispersing the released radioactivity in the
deep water masses of the Nordic Seas. An explanation for the extensive work laid down for a salvage
operation and for what became the final solution,
coverage of the torpedo-part of the hull, may be that
this submarine was said to be able to fire its torpedo
missiles with nuclear warheads from a depth of
1000 m.
In 1990, the Institute of Marine Research, Bergen,
Norway, started regular sampling of sediments and
water close to the wreck of Komsomolets. Values of
137 Cs were in the range 1–10 Bq per kg dry weight
sediment and 1–30 Bq per m
3 water. No trends were
found in the contamination as the variation between
samples taken at the same date were equal to the
variation observed from year to year. Detectable
amounts of
134
Cs in the sediment samples indicate
that there is some leaching of radioactivity from the
reactor.
Accidents with submarines and their possible impact on the marine environment are seldom noticed
in the open literature and there is therefore little
common knowledge available. An accident, however,
that is well known is the crash of a US B-52 aircraft,
carrying four nuclear bombs, on the ice off Thule air
base on the northwest coast of Greenland in January
1968. Approximately 0.4 kg plutonium ended up on
the sea floor at a depth of 100–300 m. The marine
environment became contaminated by about 1 TBq
239,240 Pu which led to enhanced levels of plutonium
in benthic animals, such as bivalves, sea-stars and
shrimps after the accident. This contamination has
decreased rapidly to the present level of one order of
magnitude below the initial levels.
Fallout from Nuclear Weapon Tests and Nuclear
Accidents
Nuclear weapon tests in the atmosphere from 1945
to 1980 have caused the greatest man-made release
of radioactive material to the environment. The most
intensive nuclear weapon tests took place before
1963 when a test-ban treaty signed by the UK, USA
and USSR came into force. France and China did not
sign the treaty and continued some atmospheric tests,
but after 1980 no atmospheric tests have taken place.
It is estimated that 60% of the total fallout has
initially entered the oceans, i.e. 370 PBq
90 Sr,
600 PBq
137 Cs and 12 PBq
239,240 Pu. Runoff from
land will slightly increase this number. As the majority of the weapon tests took place in the northern
hemisphere the deposition there was about three
times as high as in the southern hemisphere.
Results from the GEOSECS expeditions, 1972–74,
show a considerable discrepancy between the measured inventories in the ocean of 900 PBq
137
Cs,
600 PBq
90
Sr and 16 PBq
239,240
Pu and the estimated
input from fallout. The measured values are far higher
than would be expected from the assumed fallout
data. Thus the exact input of anthropogenic radionuclides may be partly unknown or the geographical
302 RADIOACTIVE WASTES
Accidents resulting in direct radioactive releases to
the sea are not well known as most of them are
connected to wreckage of submarines. Eight nuclear
submarines with nuclear weapons have been reported lost at sea, two US and six former USSR. The
last known USSR wreck was the submarine Komsomolets which sank in the Norwegian Sea southwest of Bear Island, on 7 April 1989. The activity
content in the wreck is estimated by Russian authorities to be 1.55–2.8 PBq
90 Sr and 2.03–3 PBq
137 Cs and the two nuclear warheads on board may
contain about 16 TBq
239,240
Pu equivalent to 6–7 kg
plutonium. Other estimates indicate that each warhead may contain 10 kg of highly enriched uranium
or 4–5 kg plutonium.
On August 12th 2000, the Russian nuclear submarine Kursk sank at a depth of 108 meters in the
Barents Sea north of the Kola peninsula. Vigorous
explosions in the submarine’s torpedo-chambers
caused the wreckage where 118 crew-members were
entrapped and lost their lives. Kursk, and Oscar II
attack submarine, was commissioned in 1995 and
was powered by two pressurized water reactors.
Kursk had no nuclear weapons on board. Measurements close to the wreck in the weeks after the
wreckage showed no radioactive contamination indicating that the primary cooling-systems were not
damaged in the accident. A rough inventory calculation estimates that the reactors at present contain
about 56 000 TBq. Russian authorities are planning
for a salvage operation where the submarine or part
of the submarine will be lifted from the water and
transported to land. Both a possible salvage operation or to leave the wreck where it is will be create a
demand for monitoring as the location of the wreck
is within important fishing grounds.
The wreckage of Komsomolets in 1989 and the
attempts to raise money for an internationally financed Russian led salvage operation became very
public. The Russian explanation for the intensive
attempts of financing the salvage was said to be the
potential for radioactive pollution. The wreck of the
submarine is, however, located at a depth of 1658 m
and possible leaching of radionuclides from the
wreck will, due to the hydrography of the area,
hardly have any vertical migration and radioactive
components will spread along the isopycnic surfaces
gradually dispersing the released radioactivity in the
deep water masses of the Nordic Seas. An explanation for the extensive work laid down for a salvage
operation and for what became the final solution,
coverage of the torpedo-part of the hull, may be that
this submarine was said to be able to fire its torpedo
missiles with nuclear warheads from a depth of
1000 m.
In 1990, the Institute of Marine Research, Bergen,
Norway, started regular sampling of sediments and
water close to the wreck of Komsomolets. Values of
137 Cs were in the range 1–10 Bq per kg dry weight
sediment and 1–30 Bq per m
3 water. No trends were
found in the contamination as the variation between
samples taken at the same date were equal to the
variation observed from year to year. Detectable
amounts of
134
Cs in the sediment samples indicate
that there is some leaching of radioactivity from the
reactor.
Accidents with submarines and their possible impact on the marine environment are seldom noticed
in the open literature and there is therefore little
common knowledge available. An accident, however,
that is well known is the crash of a US B-52 aircraft,
carrying four nuclear bombs, on the ice off Thule air
base on the northwest coast of Greenland in January
1968. Approximately 0.4 kg plutonium ended up on
the sea floor at a depth of 100–300 m. The marine
environment became contaminated by about 1 TBq
239,240 Pu which led to enhanced levels of plutonium
in benthic animals, such as bivalves, sea-stars and
shrimps after the accident. This contamination has
decreased rapidly to the present level of one order of
magnitude below the initial levels.
Fallout from Nuclear Weapon Tests and Nuclear
Accidents
Nuclear weapon tests in the atmosphere from 1945
to 1980 have caused the greatest man-made release
of radioactive material to the environment. The most
intensive nuclear weapon tests took place before
1963 when a test-ban treaty signed by the UK, USA
and USSR came into force. France and China did not
sign the treaty and continued some atmospheric tests,
but after 1980 no atmospheric tests have taken place.
It is estimated that 60% of the total fallout has
initially entered the oceans, i.e. 370 PBq
90 Sr,
600 PBq
137 Cs and 12 PBq
239,240 Pu. Runoff from
land will slightly increase this number. As the majority of the weapon tests took place in the northern
hemisphere the deposition there was about three
times as high as in the southern hemisphere.
Results from the GEOSECS expeditions, 1972–74,
show a considerable discrepancy between the measured inventories in the ocean of 900 PBq
137
Cs,
600 PBq
90
Sr and 16 PBq
239,240
Pu and the estimated
input from fallout. The measured values are far higher
than would be expected from the assumed fallout
data. Thus the exact input of anthropogenic radionuclides may be partly unknown or the geographical
302 RADIOACTIVE WASTES