Nuclear wastes in South Australia

Dr Gerald Laurence with radioactive material, being filmed for a television report on radioactive waste storage

Dr Gerald Laurence with radioactive material, being filmed for a television report on radioactive waste storage
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Locked away: neutron moisture probes.

Locked away: neutron moisture probes.
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Radioactive waste materials in storage.

Radioactive waste materials in storage.
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Friday, 11 August 2000

Radioactivity is a hot topic. The north of South Australia has been suggested as a premier site for a storage facility for radioactive wastes. Extensive media coverage, embracing both scientific and political argument, has ranged from factual stories, forums and surveys to conjecture and opinion columns.

Universities use radioactive materials in a variety of ways and must store and dispose of them properly. Adelaide University is one of several institutions around metropolitan Adelaide which store radioactive wastes.

Because of the public attention given to the topic, the Adelaide University newpaper, Adelaidean, invited comment from a panel of three of the University's experts on radiation safety.

Dr Gerald Laurence - Radiation Safety Officer for Adelaide and Flinders Universities. He was a member of the Australian Ionizing Radiation Council from 1990-95 and is a member of the South Australian Radiation Protection Committee.

Dr John Patterson - Associate Professor in Physics. Since 1986 he has been the Department's radiation safety officer, and holds 2 radiation licences.

Dr John Prescott - Emeritus Professor in Physics at Adelaide University. He has played a key role in nuclear science in Australia and overseas for many years, and was one of the first people appointed to the atomic energy section of Australia's Council for Scientific and Industrial Research and, later, the Atomic Energy Commission.

THE QUESTION OF RISK

Professor Prescott:
I have been engaged in some aspect of nuclear physics for all of my professional life and the issues involved have long been familiar to me. I therefore find it irksome that, almost without exception, the reporting of the topic in the media shows that the individual reporters concerned are ignorant of the scientific issues involved.

The same is true of statements attributed to politicians. A classic example occurred (in the media) about 2 years ago. It featured the three party leaders, and the matter under discussion was the transport of radioactive material to Woomera. It was clear that none of those in the discussion, including the talk host, had any more than a vague idea of whether the materials involved any risk to the public in general or to individuals and, if they did, why.

The element missing from almost all discussions is any assessment of risk. In other words, what, if any is the risk to the population in general and South Australians in particular. People make judgements of "risk" every day of their lives. Usually our willingness to take a risk depends on how familiar we are with the situation. For example, do we cross the road now or, is it safe to drink this water? Those who climb Mt Everest do so in the knowledge that it is very very risky. Decisions affecting risks to the population in general are being made all the time by authorities and governments.

There is some level of risk for handling and storing radioactive material, just as there is some risk in handling farm and garden chemicals, or running an X-ray machine and the risk depends on the total amount or number of items. For radiation safety, the ALARA Principle applies, viz, As Low As Reasonably Achievable. And this is done by adopting three working rules: When dealing with radiation, stay as far away as possible, provide suitable shielding and keep your stay short, or stay away.

These principles apply to any proposal to store radioactive materials in South Australia and it on this basis that any proposal must be judged. Emotion is a poor substitute.

Dr Laurence:
My views are formed from 25 years experience in maintaining a radiologically safe environment for my colleagues and overseeing the safe use of radiation in SA so that workers and the public are not exposed to undue risk from ionising radiation.

There is a need for a storage facility for low and intermediate level wastes independent of concerns or assurances about a high level facility. These wastes exist now. Concerns about safety make it sensible for storage to be undertaken as a public good rather than for hundreds of individual organisations to be responsible for the long-term management of individual repositories.

Public management of any form of dangerous waste is more likely to produce satisfactory outcomes than private storage and there are management advantages in having just one store for Australian waste. The operation of the store will have to comply with the Australian standards. The material is covered by state and commonwealth radiation safety legislation while it is in current use and will not become exempt from these requirements by being transferred to the store.

A STORAGE FACILITY FOR SOUTH AUSTRALIA?

Professor Patterson:
Australia has a national responsibility to dispose of its radioactive wastes from hospitals, universities and the Australian Nuclear Science and Technology Organisation safely, securely and environmentally responsibly. I strongly support the establishment of a National Radioactive Waste Repository for low and intermediate level waste produced in Australia.

The best arguments for the establishment of a radioactive storage facility (in South Australia's far north) are environmental considerations, low rainfall, it is away from underground water, distant from population centres and has stable geology. There are no scientific, only political, reasons (against such a storage facility).

The question (of a high-level facility) is hypothetical. There should be minimal or zero high-level waste. No high level waste facility is planned for Australia. Unfortunately, people are not willing to believe the government.

Dr Laurence:
While we have a responsibility to our own citizens to handle our radioactive waste sensibly and safely, the argument that as an exporter of uranium Australia has a responsibility to store wastes from that material ignores the responsibilities of the purchasers.

Professor Prescott:
Since at least 1993 The National Radioactive Waste Repository Study has been seeking suitable locations for a repository for low level waste. Many possible sites were considered, and now a final assessment of several sites in South Australia is about to be made.

From a risk point of view, the site is remote so that few people need ever be near it. It also has the possibility for being more secure than the places where the materials are stored at present. The geology of the area should ensure that the radioactive substances stay where they are put. In the case of these sites, shielding by burial would be possible although I understand that this is not proposed at this time. In my view, the sites proposed are suitable and will constitute no risk to the people of Australia.

The same principles apply to the location of medium and high level waste but it is my understanding that no decision has been made and that no decision need be made until 2005.

Dr Laurence:
The site requirements to minimise the harm to the public and the environment (geology, access, geomorphology etc) made sites in SA likely choices. The risk posed to South Australians by the store is extremely low and much less than the risk from the many smaller stores in suburban areas. Risks can be assessed in areas such as:

1. radiation dose at the store - the exposure of site workers can be estimated and is certain to be very much less than the current annual dose limit of 20 milliSievert per year, and can be easily monitored and controlled.
2. leakage of material from the store into the environment - transport of material through the soil is limited by siting the store in a low rainfall area. Transport to the water table is limited by the site characteristics. In many parts of SA natural radioactive materials have not entered underground water systems in significant quantities. Local floods are a much larger hazard to materials currently stored in urban areas around Adelaide.
3. transport of waste to the site -

HOW SHOULD RADIOACTIVE WASTES BE TRANSPORTED?

Professor Patterson:
In accordance with the strict conditions laid down by the Australian code of practice for safe transport of radioactive materials. There are restrictions placed on transport through populated areas.

Dr Laurence:
The national and international regulations for the transport of radioactive materials provide no significant exposure to populations through which the waste is transported; much more hazardous material is transported by road every day, such as LPG, chlorine, ammonia and so on.

OTHER COMMENTS

Professor Patterson:
The real agenda is to stop the replacement research reactor and deny Australian science, hospitals and industry access to a state-of-the-art facility and medical/industrial isotopes.

Dr Laurence:
These wastes exist now. The medium level waste from the HIFAR reactor will need to be stored when the reactor is decommissioned, regardless of whether a replacement reactor is built.

One claim made by opponents of the store is that a store will ruin South Australia's "clean, green, food and wine" image. Ironically the most rapidly growing use of radiation in SA is the use of neutron moisture meters to monitor soil moisture in vineyards. This is to produce better wines and make the most economical use of irrigation water. The neutron sources need to be stored in a low or medium level waste repository when their working life is over.

 

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