With modern developments in the non-nuclear production of medical isotopes, perhaps it's also time to shut down the Lucas Heights nuclear reactor and stop producing dangerous radioactive trash, writes Noel Wauchope.
Watching the Australian media last week, you would be sure that the government's hunt for a nuclear waste disposal site was solely to do with medical wastes. Rarely do they mention the real impetus for this hasty search, which is Australia's current obligation to take back processed nuclear wastes from France. Later, we will have to receive similar wastes returning from UK.
The "nuclear medicine" pitch makes it seem essential – beneficial – to set up a centralised radioactive waste disposal site somewhere remote from big centres of population, so that Australians can have that essential nuclear medicine. But this is nonsense, because the vast majority of medical radioisotopes have very short half-lives, so there's no need for them to be moved beyond the site of use. The most common diagnostic radioisotope is technetium-99m, which has a half-life of 6 hours. Only a very few therapeutic radioisotopes do have longer half-lives, such as Co-60 (5.3 years) and Cs-137 (30 years).
The real problem is the returning intermediate level wastes from Australia's used nuclear fuel rods reprocessed overseas. Nuclear reprocessing reduces the volume of high-level waste but, by itself, does not reduce radioactivity or heat generation and, therefore, does not eliminate the need for a geological waste repository.
Nuclear medicine has been the fig leaf on the nuclear industry for decades. I have not been able to discover what proportion of the Lucas Heights OPAL nuclear reactor's activities are, in fact, directed to medical uses, but that was certainly not its original purpose and not necessarily its major purpose now. It is hard for a non-specialist in nuclear technology to gauge this.
As a guide, Wikipedia says:
'The neutrons produced by a research reactor are used for neutron scattering, non-destructive testing, analysis and testing of materials, production of radioisotopes, research and public outreach and education.'
Australia's research reactor had its origins in the late 1940s, directed at the aim of eventually getting a nuclear weapon. The concept of a medical use for nuclear reactors also originated in America at that time:
'The main mission of the AEC was promoting the military use of nuclear material, but “giving atomic energy a peaceful, civilian image” was also part of it. Including the promotion of research, among which were radiobiology and nuclear medicine.'
Still, it must be acknowledged that the medical radioisotopes produced at Lucas Heights do have their valuable uses in diagnostics and in the treatment of cancers.
However, it also must be recognised that all these radioisotopes can be produced without use of a nuclear reactor. This is happening increasingly and, rather like the distributed renewable energy boom, the world could be on the brink of a distributed medical radioisotope boom.
Canada and some in the USA certainly think so, judging by recent reports. The World Nuclear Association reports on University of British Columbia's success in quadrupling the rate of production of medical radioisotopes using a (non-nuclear) cyclotron. Nova Scotia's QEII Health Sciences Centre’s cyclotron was granted a Drug Establishment Licence (DEL) from Health Canada in June 2015
In USA, Niowave Inc, NorthStar Medical Radioisotopes and SHINE Medical Technologies, are competing in the market for medical isotopes, produced in a (non-nuclear) linear accelerator.
The non-nuclear production of medical isotopes has it all over the centralised production by nuclear reactor. This is not just because it eliminates the obvious dangers of nuclear wastes, weapons proliferation, terrorism risks, disastrous accident, and radiation emissions.
It's because the greatest uses of medical radiopharmaceuticals involve very short-lived isotopes. Because most medical isotopes have short half-lives, they can't be stockpiled like other more stable products, such as vaccines. The half-life of Molybdenum-99 (the isotope used to produce Tc-99m) is 66 hours. The half-life of Tc-99m is six hours. Generators, containers that encase Molybdenum-99 degrading to Tc-99m, expire after two weeks. That makes them much better suited to localised production, in or near hospitals. The delivery of pharmaceuticals to patients is much more secure. In addition, the risk of transport accidents is close to zero.
I don't want to digress here into the pros and cons of nuclear medicine. However, that is a subject that should be explored. Along with the undoubted benefits to many sick people, there are the hazards — to patients, relatives and staff. Overuse of medical radiation is a problem now acknowledged widely.
The medical use of radioisotopes was begun in 1941, using a particle accelerator and, globally, these isotopes were made in that way until the 1950s. During the Manhattan Project, nuclear reactors began to be used for medical isotope production and, ever since World War II, the nuclear industry has found this to be very fine public relations.
With all the fuss about finding a dump sites for 'Olympic sized pools of medical radioactive waste', it is time for the government and media to fess up to the real purpose of this hunt. And with modern developments in the non-nuclear production of medical isotopes, perhaps it's also time to shut down the Lucas Heights nuclear reactor and stop producing dangerous radioactive trash.
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