Gerry White, IThEO Australia Representative, writes a primer for a serious debate on how we ought to build our energy future.
Whilst much support and investment, both private and government, has been made in carbon capture and storage, solar power in its various forms, geothermal power, and wind power, there has been a notable absence of a dispassionate debate about the merits and contribution that nuclear power could make to Australia’s energy production mix.
All too often the debate is reduced to opposing intransigent positions, with the nuclear proponents claiming that all the major problems have been resolved, and the opponents of nuclear power vigorously disagreeing.
There are a series of major issues associated with the current 3rd generation nuclear power plants that are being deployed in a number of countries, many of which stem from the adoption for commercial power producing reactors of the Uranium/Plutonium (U/P) fuel cycle. This choice was driven some 50 to 60 years ago by the needs of the military both for plutonium for bombs, and high powered compact reactors for nuclear submarines. Arising from these decisions a number of challenges arose when these technologies were adopted for civilian use as set out below:
- Very expensive and complex engineered safety systems.
- Construction of the necessary large primary pressure vessels and forgings, to the highest engineering standards.
- Long term storage of irradiated fuel.
- Long term storage of the actinide wastes if re-processing is undertaken to recover the uranium and plutonium.
- Diversion of technology and fissile material for illicit weapons manufacture.
- Transport of high active waste for re-processing and storage.
- Questionable economics due to construction cost escalation and programme delays, open ended decommissioning costs, and unknown long term storage costs for the large quantities of highly active waste produced.
- Consenting of new plants and regulation of operating plants.
The adoption of, what has been called, 3rd generation nuclear reactors has made the scale of most of these problems even greater than before. AREVA’s recent experience with their first three EPR type reactors under construction bears testament to this, with massive cost escalation and major construction delays.
Whilst all of the proposed new nuclear reactors are enhanced derivative designs of the PWR/BWR/CANDU reactors already in operation, any meaningful debate about the adoption of nuclear power should consider other possible nuclear fuel cycles other than the uranium/plutonium cycle system currently being offered in the market.
In reviewing alternative fuel cycles, the Thorium fuel cycle stands out as having many inherent advantages over the U/P cycle. There is currently considerable international activity examining which particular design of reactor offers the preferred way forward for Thorium Energy, with many teams of engineers and physicists examining the optimum designs for Thorium fuelled reactors as part of an ongoing strategy leading to the deployment of Thorium Energy for power production. In support of these developments a Thorium Energy Conference is to be held in London at the Royal Institution in mid October-ThEC2010.
The Molten Salt Reactor (MSR) fuelled with thorium offers a very promising solution. The origins of the Thorium MSR date back to a very successful development programme at the Oak Ridge National Laboratory in the USA culminating in almost 5 years successful operation of an 8 MW thermal MSR during the period 1965 to 1969. This programme demonstrated the many advantageous aspects of the MSR, such as very high temperature operation (650 degrees centigrade), high power densities, the on-line removal of fission products, and on-line re-fuelling. This work has been extended in the intervening years to develop designs that breed the fuel from naturally occurring thorium. Some of the many advantages of a thorium fuelled MSR are:
- Thorium is 3 times more abundant than Uranium and much cheaper, with Australia having potentially the world’s largest reserves.
- It can breed its own fissile material within the reactor, thereby obviating the need for enrichment plants as required for uranium, with all the nuclear proliferation risks that uranium enrichment entails.
- The Thorium fuel cycle is very resistant to diversion of fissile material for weapons manufacture.
- Very high degree of inherent safety, such that the reactor shuts itself down in the event of any accident or loss of power supplies, without the need for highly engineered safety systems or operator intervention.
- The quantity of high active actinide waste is reduced by a factor of between 1000 and 10,000 times that of the current nuclear reactors based on the very high fuel burn-up.
- The small quantity of highly active waste allows cost effective on-site storage to be considered, thereby removing the need to transport fissile and high active waste materials around the country.
- Very stable reactor operations which allow load following and reduced complexity of the reactor safety systems.
- No need for very high pressure reactor vessels and coolant loops.
- The high reactor power density results in much smaller and cheaper plants, which can be designed for economic operation at smaller sizes than the current 3rd generation of water cooled reactors.
- The high temperatures achieved allow the MSR to be considered as the heat source for zero-carbon hydrogen production along with much improved thermal efficiency for electrical power generation.
- Offers a real opportunity to effect a conservative 30-40% capital cost reduction, due to the ability to manufacture the much smaller reactor core and heat exchangers entirely under factory conditions.
- The deployment of a Thorium fuelled fleet of MSR’ ,with load following capability, in combination with the range of developing renewable technologies offers an optimum way of meeting a country’s base load and peak load requirements with zero carbon emissions.
In many countries the current opposition to the adoption of commercial nuclear power appears to be largely based on the problems surrounding long term storage of high active waste, and the risk of fissile materials being used for military purposes. Many of the other issues rarely form part of any debate or policy discussion. The very broad range of matters associated with the decision to adopt nuclear power as a component of a country’s strategy for replacing carbon emitting stationary energy plants will require the involvement of a broad range of expertise and academic disciplines.
A national debate will have to consider in depth, at a minimum, the following spectrum of topics:
- Reactor types to be considered and their state of development and recent experience.
- Inherent safety characteristics of reactor types.
- Economics, both capital and operational costs, including de-commissioning costs and final fuel charge disposal.
- Waste production (type and quantity) and eventual long term storage.
- Ethical and moral issues regarding the legacy left to future generations, and for how long.
- Nuclear proliferation resistance.
- Fuel reprocessing.
- Human capital for the establishment of a nuclear industry and a suitable regulatory authority.
- Development of the necessary industrial base to support a nuclear programme.
- Ownership and hence financing.
- Export opportunities created.
- International collaboration.
- Integration with the existing national grid transmission system.
Such a debate around these matters will allow Australia to take an informed decision as to whether it wishes to develop a nuclear option, and in particular whether it wishes to develop an alternative option based on Thorium Energy and MSR ‘s for meeting its energy needs over the coming decades.
It is no longer a matter of being “pro” or “anti” nuclear. The time has come to have a serious debate.