Nuclear Waste

Sources and Types

Nuclear waste, like any waste, needs to be managed to protect people and the environment. Nuclear waste is radioactive waste that results from the nuclear industry. It comes from the mining and processing of uranium, nuclear weapons, nuclear reactors, and nuclear power stations. Such waste is classified as either low-level, intermediate level, or high level, depending on the amount and type of radioactive material in it.

Low-level radioactive waste comes from hospitals, universities, nuclear power stations, nuclear research facilities, government laboratories, smoke detectors and industry. It needs to be disposed of in a different manner to household waste. Low-level radioactive waste should be securely stored above ground in properly engineered and monitored facilities as close as possible to the site at which it was produced. Because it remains dangerous for thousands of years and because of the the possibility of it getting into the ecosystem and then into the food chain, it should not be buried. Intermediate level radioactive wastes come from uranium processing and enrichment plants, from nuclear weapons facilities, and from nuclear power plants.  It usually needs to be shielded. That is, surrounded by materials such as lead and concrete that protect people from the ionizing radiation. Intermediate level waste should be encapsulated and securely stored above ground in properly engineered and constructed facilities as close as possible to the site at which it was produced. High level radioactive waste comes from spent fuel from nuclear reactors, such as those at Lucas Heights near Sydney. It must be shielded and cooled at the site of the nuclear reactor.

Management of highly radioactive nuclear waste is a major problem, which has not been satisfactorily solved by any country. The favoured initial step in its management is to encapsulate it in glass. Australian scientists have been very critical of this process and favour an alternative encapsulation medium called Synroc. Despite many years of research and development costing many millions of taxpayer dollars, this preferred process has yet to be commercialized.

A nuclear power station produces about 30 kilogram of high level nuclear waste per year.

The production of the reactor fuel (uranium enriched in the fissile isotope U-235) results in much larger quantities of lower level nuclear waste during mining, conversion of uranium oxide to uranium hexafluoride, and during enrichment. Finally, the nuclear power station itself becomes nuclear waste when it is decommissioned.

Once uranium has been used in a nuclear reactor, it becomes spent fuel. As this spent fuel is highly radioactive, it cannot be encapsulated and stored. It is often stored in special ponds that allow the fuel to cool down and to decrease its radioactivity.

Although the spent fuel can be stored in these special ponds for fairly long periods of time, space limitation mean that eventually the fuel needs to be either reprocessed, or encapsulated and stored.

South Australia has more nuclear waste sites than any other State or Territory in Australia.

This includes:

• Mining of uranium for nuclear weapons at Radium Hill.
• Processing of that uranium at Port Pirie.
• Testing of nuclear weapons at Maralinga and Emu Field.
• Uranium ore testing at Dry Creek and Thebarton.
• Nuclear waste dumping at Radium Hill.
• Uranium mining at Roxby Downs, Beverley and Honeymoon.
• Storage of Federal Government contaminated soil and radioactive instruments at Woomera.

The Federal Government now plans to dump more nuclear waste in South Australia, including wastes from Lucas Heights.

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/.

In this section - Nuclear Waste

• Sources and types
• Uranium mines
• Nuclear weapons test sites
• Lucas Heights
• Nuclear research and medicine
• Federal Government Plans