Nuclear Waste
Lucas Heights
Lucas Heights near Sydney has been the centre of the Australian
Government's nuclear operations since 1956.
The facility was initially under the control of the Australian
Atomic Energy Commission (AAEC), which was set up in 1953.
Over the years the focus of the facility has changed from
preparing for nuclear power in Australia
to a broader range of nuclear activities including nuclear power, uranium mining
, nuclear medicine and nuclear research, industrial uses,
and environmental management of former uranium mining sites such as Rum Jungle in the Northern
Territory.
An attempt by the AAEC to build a nuclear power station
at Jervis Bay south of Sydney was eventually
abandoned in 1972. No further attempts to build nuclear power stations
in Australia have been made since then.
The AAEC was replaced in 1987 by the Australian Nuclear
Science and Technology Organization (ANSTO).
Two nuclear reactors have been built at Lucas Heights.
The smaller reactor Moata has been mothballed. The larger reactor HIFAR
(High Flux Australian Reactor) is over 40 years old (began operations in
1958) and is due to be shut down within the next ten years.
A decision has been made to replace HIFAR with a bigger
reactor built in Argentina. This project awaits the drawing up of firm
plans for the management of nuclear waste from the reactor. These plans
have been set back by the South Australian
Government's decision to prohibit importation of intermediate and high
level nuclear waste into SA.
Lucas Heights is by far the largest single source of radioactive
waste in Australia. This waste includes the mothballed Moata nuclear reactor
and will eventually include HIFAR.
Reactor fuel waste
The most dangerous nuclear waste generated at Lucas Heights
is the spent fuel, which is currently being
stored in pools of water. Spent fuel is an inevitable part of operating
HIFAR and is constantly being produced. If the larger Argentinean nuclear
reactor is built then the rate of production of nuclear fuel waste
will increase significantly.
When spent nuclear fuel rods are removed from a nuclear
reactor, they are hot and very radioactive. The spent nuclear fuel must
be cooled and workers must be protected against the ionizing radiation.
The spent nuclear fuel is stored in ponds of water at the nuclear reactor
site. The storage ponds are steel lined concrete tanks, about 8 metres
deep. The water cools the spent nuclear fuel rods and acts as a shield
to protect the workers against the ionizing radiation. The heat and radioactivity
decrease over time - after about 40 years they are down to about 1/1000
of what they were when taken from the reactor, but they are still highly
radioactive. The longer they are stored, the easier they are to deal with.
Some nuclear fuel waste is sent to plants in the
United Kingdom and France where plutonium
and unused uranium are separated from the most highly radioactive isotopes.
The plutonium is formed from the dominant uranium isotope U-238. The separated
uranium and plutonium may be used in either nuclear weapons
or as fuel for nuclear reactors. In both France and
the UK the reprocessing is carried out by the Government, which also controls
the nuclear weapons facilities.
The plutonium presents a special problem because it is
the preferred explosive for nuclear weapons.
In some cases the plutonium is mixed with uranium to make
mixed oxide (MOx) nuclear reactor fuel.
Disposal of spent nuclear fuel waste and encapsulated
waste has been delayed for many years due to the difficulty of finding
suitable disposal sites.
Greater technical detail can be found on this topic by searching through
the listed briefing papers and education resources at
http://www.ccsa.asn.au/nic/.
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