NUCLEAR FUEL REPROCESSING AND RELATED
DISCHARGES
H. N. Edmonds, University of Texas at Austin,
Port Aransas, TX, USA
Copyright & 2001 Elsevier Ltd.
Introduction
Oceanographers have for some decades made use of
human perturbations to the environment as tracers
of ocean circulation and of the behavior of similar
substances in the oceans. The study of the releases of
anthropogenic radionuclides – by-products of the
nuclear industry – by nuclear fuel reprocessing plants
is an example of such an application. Other examples of the use of anthropogenic substances as
oceanographic tracers addressed in this Encyclopedia
include tritium and radiocarbon, largely resulting
from atmospheric nuclear weapons testing in the
1950s and 1960s, and chlorofluorocarbons (CFCs), a
family of gases which have been used in a variety of
applications such as refrigeration and polymer
manufacture since the 1920s. As outlined in this
article, the source function of nuclear fuel reprocessing discharges, which is very different from
that of either weapons test fallout or CFCs, is both a
blessing and a curse, defining the unique applicability
of these tracers but also requiring much additional
and careful quantification.
The two nuclear fuel reprocessing plants of most
interest to oceanographers are located at Sellafield, in
the UK, which has been discharging wastes into the
Irish Sea since 1952, and at Cap de la Hague, in
north-western France, which has been discharging
wastes into the English Channel since 1966. These
releases have been well documented and monitored
in most cases. It should be noted, however, that the
releases of some isotopes of interest to oceanographers have not been as well monitored
throughout the history of the plants because they
were not of radiological concern, were difficult to
measure, or both. This is particularly true for
99
Tc
and
129
I, which are the isotopes currently of greatest
interest to the oceanographic community but for
which specific, official release data are only available
for the last two decades or less. The radionuclides
most widely studied by ocean scientists have been
137 Cs,
134 Cs,
90
Sr,
125 Sb,
99
Tc,
129
I, and Pu isotopes.
The Sellafield plant has dominated the releases of
most of these, with the exception of
125 Sb and, particularly in the 1990s,
129 I. In general, the Sellafield
releases have been particularly well documented and
are the easiest for interested scientists and other
parties to obtain. The figures of releases presented in
this article are based primarily on the Sellafield data,
except where sufficient data are available for Cap de
la Hague.
The location of the Sellafield and Cap de la Hague
plants is important to the oceanographic application
of their releases. As discussed below, the releases
enter the surface circulation of the high latitude
North Atlantic and are transported northwards
into the Norwegian and Greenland Seas and the
Arctic Ocean. They have been very useful as tracers
of ventilation and deep water formation in these
regions, which are of great importance to global
thermohaline circulation and climate. In addition,
the study of the dispersion of radionuclides from
the reprocessing plants at Sellafield and Cap de la
Hague serves as an analog for understanding
the ultimate distribution and fate of other wastes
arising from industrial activities in north-western
Europe.
Much of the literature on reprocessing releases in
the oceans has focused on, or been driven by, concerns relating to contamination and radiological effects, and they have not found the same broad or
general oceanographic application as some other
anthropogenic tracers despite their great utility and
the excellent quality of published work. This may be
attributable to a variety of factors, including perhaps
(1) the contaminant-based focus of much of the work
and its publication outside the mainstream oceanographic literature, (2) the complications of the source
function as compared with some other tracers, and
(3) the comparative difficulty of measuring many of
these tracers and the large volumes of water that
have typically been required. This article addresses
the historic and future oceanographic applications of
these releases.
A Note on Units
In most of the literature concerning nuclear fuel reprocessing releases, amounts (both releases and ensuing environmental concentrations) are expressed in
activity units. The SI unit for activity is the becquerel
(Bq), which replaced the previously common curie
291
DISCHARGES
H. N. Edmonds, University of Texas at Austin,
Port Aransas, TX, USA
Copyright & 2001 Elsevier Ltd.
Introduction
Oceanographers have for some decades made use of
human perturbations to the environment as tracers
of ocean circulation and of the behavior of similar
substances in the oceans. The study of the releases of
anthropogenic radionuclides – by-products of the
nuclear industry – by nuclear fuel reprocessing plants
is an example of such an application. Other examples of the use of anthropogenic substances as
oceanographic tracers addressed in this Encyclopedia
include tritium and radiocarbon, largely resulting
from atmospheric nuclear weapons testing in the
1950s and 1960s, and chlorofluorocarbons (CFCs), a
family of gases which have been used in a variety of
applications such as refrigeration and polymer
manufacture since the 1920s. As outlined in this
article, the source function of nuclear fuel reprocessing discharges, which is very different from
that of either weapons test fallout or CFCs, is both a
blessing and a curse, defining the unique applicability
of these tracers but also requiring much additional
and careful quantification.
The two nuclear fuel reprocessing plants of most
interest to oceanographers are located at Sellafield, in
the UK, which has been discharging wastes into the
Irish Sea since 1952, and at Cap de la Hague, in
north-western France, which has been discharging
wastes into the English Channel since 1966. These
releases have been well documented and monitored
in most cases. It should be noted, however, that the
releases of some isotopes of interest to oceanographers have not been as well monitored
throughout the history of the plants because they
were not of radiological concern, were difficult to
measure, or both. This is particularly true for
99
Tc
and
129
I, which are the isotopes currently of greatest
interest to the oceanographic community but for
which specific, official release data are only available
for the last two decades or less. The radionuclides
most widely studied by ocean scientists have been
137 Cs,
134 Cs,
90
Sr,
125 Sb,
99
Tc,
129
I, and Pu isotopes.
The Sellafield plant has dominated the releases of
most of these, with the exception of
125 Sb and, particularly in the 1990s,
129 I. In general, the Sellafield
releases have been particularly well documented and
are the easiest for interested scientists and other
parties to obtain. The figures of releases presented in
this article are based primarily on the Sellafield data,
except where sufficient data are available for Cap de
la Hague.
The location of the Sellafield and Cap de la Hague
plants is important to the oceanographic application
of their releases. As discussed below, the releases
enter the surface circulation of the high latitude
North Atlantic and are transported northwards
into the Norwegian and Greenland Seas and the
Arctic Ocean. They have been very useful as tracers
of ventilation and deep water formation in these
regions, which are of great importance to global
thermohaline circulation and climate. In addition,
the study of the dispersion of radionuclides from
the reprocessing plants at Sellafield and Cap de la
Hague serves as an analog for understanding
the ultimate distribution and fate of other wastes
arising from industrial activities in north-western
Europe.
Much of the literature on reprocessing releases in
the oceans has focused on, or been driven by, concerns relating to contamination and radiological effects, and they have not found the same broad or
general oceanographic application as some other
anthropogenic tracers despite their great utility and
the excellent quality of published work. This may be
attributable to a variety of factors, including perhaps
(1) the contaminant-based focus of much of the work
and its publication outside the mainstream oceanographic literature, (2) the complications of the source
function as compared with some other tracers, and
(3) the comparative difficulty of measuring many of
these tracers and the large volumes of water that
have typically been required. This article addresses
the historic and future oceanographic applications of
these releases.
A Note on Units
In most of the literature concerning nuclear fuel reprocessing releases, amounts (both releases and ensuing environmental concentrations) are expressed in
activity units. The SI unit for activity is the becquerel
(Bq), which replaced the previously common curie
291