Nuclear power and ‘Promethean Environmentalism’

First, uranium supplies are small, such that if the world was wholly powered by nuclear reactors, there would be at most a few decades of energy to use before our resource was exhausted and the power plants would have to shut down.

Second, nuclear accidents have happened in the past, and therefore this power-generation technology is inherently dangerous.

Third, expansion of nuclear power would axiomatically risk the proliferation of nuclear weapons.

Fourth, in taking the short-term nuclear energy option, we would be bequeathing future generations with the legacy of long-lived nuclear waste requiring thousands of years of management.

Fifth, large amounts of energy (and possibly greenhouse gases) would be required to mine, mill and enrich uranium, and to construct and later decommission the nuclear power stations themselves.

Cost and embedded energy arguments used against nuclear are complex and must be left for another time, because to be addressed fairly, this also requires a critical examination of the costs and embedded energy requirements for the alternative sources (renewables and fossil fuels).

Now all five of the above points have some merit, although their relative importance compared to threat of climate change and the societal disruption caused by critical energy shortages is debatable. The chaos and bitter complaints which stemmed from the power shortages experienced during the current heatwave in southern Australia demonstrate how dependent we are on a secure, reliable energy supply. But to be honest, there is little point in even having a debate on how persuasive these five objections are, because none will be applicable to future nuclear energy generation.

Of the 440 commercial nuclear power stations operating worldwide today and supplying 16 per cent of the world’s electricity, almost all are “thermal spectrum” reactors. This technology, first developed for the US Navy in the early 1950s, uses ordinary or heavy water to both slow the neutrons which cause uranium atoms to split (fission) and to carry the heat generated in this controlled chain reaction to a steam turbine to generate electricity. Because of the gradual build-up of fission products (nuclear poisons) in fuel rods over time, we end up getting about 1 per cent of the useable energy out of the uranium, and throw the rest out as that problematic long-lived high-level waste.

With 50 years of subsequent development, the nuclear industry has come a long way in terms of efficiency, costs reductions and risk minimisation. Modern reactors are incredibly safe, with physics-based “passive” safety systems requiring no user-operated or mechanical control to shut down the reaction. Indeed, a certification assessment for the “Generation III+” Economic and Simplified Boiling Water Reactor (ESBWR) put the risk of a core meltdown as severe as the one which occurred at Three Mile Island (TMI) in 1979 at once every 29 million years. For reference, the TMI incident resulted in no deaths. Similarly, comparing the inherently unsafe Chernobyl reactor design, with a flawed design and no containment building, to an ESBWR, is akin to comparing an army revolver to a water gun.

“Fast spectrum” liquid metal reactors, and molten salt liquid fluoride reactors, also known as “Generation IV”, are able to use 99.5 per cent of the energy in uranium or thorium. There is enough energy in already-mined uranium and stored plutonium from existing stockpiles to supply all the world’s power needs for over a century before we even need to mine any more uranium to supply Gen IV - although I should note, for Australia’s immediate benefit, that uranium mining will need to continue for at least 40 years to ensure ongoing supply to the world’s currently operating Gen II and recently built Gen III/III+ reactors. Looking further ahead, there is enough energy in proven uranium and thorium deposits to supply the entire world for at least 50,000 years. Gen IV reactors can also burn up all existing reserves of plutonium and the “high-level waste stream” (spent fuel from the once-through cycle) of past and present Gen II/III reactors.

The safety features of Gen IV designs, due for instance to the metal alloy fuel used, is superior even to the ESBWR. The nuclear fuel used by fast reactors is fiendishly radioactive and contaminated with various heavy elements (which are all eventually burned up in the power generation process!), making it impossible to divert to a nuclear weapons program without an expensive, heavily shielded off-site reprocessing facility which would be easily detected by inspectors.

Yet in reality the only nuclear waste material that will ever leave an Integrated Fast Reactor complex (a systems design for a Gen IV power station which includes on-site reprocessing) are fission products, which decay to background levels of radiation with a few hundred years (not hundreds of millennia), and can be readily stored because they produce so little heat compared to “conventional” nuclear waste.