Emeritus professor ERICH WEIGOLD, of the ANU Research School of Physics and Engineering, says there is an argument for safe, nuclear energy to support Australia’s ambitions for a carbon-free baseload power future.
THE Chief Scientist, Dr Alan Finkel, considers that de-carbonisation of Australia’s energy needs should be technology neutral. Nuclear energy should be part of that consideration.
When the ABC polled Australians for “Australia Talks”, 34 per cent of respondents named nuclear as the preferred energy source, after solar, wind and hydro, ahead of gas, biomass and coal in that order.
A reliable future electricity system needs dispatchable baseload power to back up the renewable energy sources. When renewables are not delivering the necessary power, storage batteries are totally inadequate and far too expensive as replacements.
System stability needs large inertial power sources. Currently this means gas, coal or hydro power. Of these, only hydro is carbon neutral. But existing hydro power cannot adequately provide Australia’s baseload requirements if carbon-emitting power decreases.
The only other proven “carbon-free” baseline power source is nuclear. Currently some 30 countries use nuclear to provide some of their power needs. In 2017, 13 countries produced at least one quarter of their electricity from nuclear. Bangladesh, Belarus, Turkey and the United Arab Emirates are constructing their first nuclear power plants. More than 50 countries, including Australia, utilise nuclear energy in research reactors.
Public concern for the safety of nuclear reactors is understandable. The major nuclear disasters at Chernobyl and Fukushima were caused by mistakes in safely closing reactors down.
At Chernobyl, a safety test was delayed by 10 hours by which time the operating shift that had been prepared for the test was not present. The test supervisor then failed to follow procedure, which combined with the intentional disabling of several nuclear safety systems and some faults in reactor design, led to the disaster.
The Fukushima disaster was triggered by a tsunami sweeping over the plant’s seawall and knocking out emergency generators needed to run pumps supplying cooling water to the reactors, which had been shut down automatically when the earthquake was detected.
TEPCO, the operator, had ignored warnings that the seawall might be inadequate protection from predictable tsunamis and that the back-up generators and electrical switching equipment needed to be located in a flood-proof environment. It has also been said that contributing factors to the accident were Japan’s rigid bureaucratic structure, the need to save face, a reluctance to send bad news upwards, and TEPCO’s very hierarchical management culture.
The probability of core damage or loss of structural integrity (CDF) for modern nuclear reactors is close to one in a million years. Small Modular Reactors (SMR), which have safely powered submarines, aircraft carriers and icebreakers for several decades, are even safer. SMRs, built by American company NuScale Power Modules, have CDFs of only one in three billion years.
Built in a factory, SMRs cost less and are truckable to underground sites where they can be passively cooled in water. They do not need back-up power supply or proximity to a large water source. As demand for power increases further modules can be added. They can be designed for load-follow, making them suitable for use in power systems with significant variable renewable power.
NuScale power plant reactors are designed to hold up to 12 Modules each delivering 60 MWe. NuScale’s first SMR 720 MWe (gross) power plant is scheduled to begin commercial operation for the Utah Associated Municipal Power System in 2026. The target “levelized cost of electricity” of around $A95 per MWh compares with estimates of $A84-$A94 per MWh for conventional power stations burning supercritical black coal, not including any additional cost of managing the emitted carbon dioxide.
There is also public concern about disposing nuclear wastes in ways that safeguard human health and minimise environmental impact. Many countries are already doing that safely.
Large geological radioactive sources have existed naturally for billions of years. In Gabon, about two billion years ago, a rich source of natural uranium deposit produced spontaneous large nuclear reactions which ran for many years. Since then the long-lived radiation produced by those naturally occurring nuclear reactors has migrated less than 10 metres despite thousands of centuries of tropical rain and groundwater exposure.
We should be able to ensure even better containment than that achieved by such a random natural event. To say that storage in stable geological deposits is unsafe for long term storage of radioactive waste is a fallacy.
We need to convince our elected political representatives that Australia’s future may well depend on amending the Environmental Protection and Biodiversity Act 1999 to facilitate establishment of nuclear power using SMRs, as part of the next national energy strategy.
This is an abridged text of a submission by Emeritus Professor Erich Weigold, of the ANU Research School of Physics and Engineering, to the House of Representatives Standing Committee on the Environment and Energy Inquiry into the Prerequisites for Nuclear Energy in Australia.