Thursday, February 02, 2012

Fast Nuclear Reactor Technology Still Alive in UK

Nuclear Street

Despite rumours to the contrary, Britain has not rejected the fast reactor concept as presented by GE Hitachi (PRISM). Talks will continue for at least 6 months, according to Nuclear Decommissioning Authority officials.
Britain's large stockpile of nuclear waste includes more than 100 tonnes of plutonium and 35,000 tonnes of depleted uranium. The plutonium in particular presents a security risk as a potential target for terrorists and will cost billions to dispose of safely...The engineering firm GE Hitachi has submitted [a] ... proposal based on their Prism fast reactor, which could consume the plutonium as fuel while generating electricity.

"It's a very elegant idea that we should try and use [the waste] as efficiently as possible. I definitely find it an attractive idea", said Prof David MacKay, Decc's chief scientific adviser.

Recent news reports have suggested this proposal has been rejected by the government and Nuclear Decommissioning Authority (NDA) on the grounds of being too far from commercial viability.

However, the Guardian has confirmed that talks between GE Hitachi, Decc and the NDA are continuing. MacKay told the Guardian: "My position as chief scientific adviser at Decc is that I think Prism is an interesting design and I'd like to see [details about its credibility] worked out." A spokesperson for the NDA said: "The statement that the NDA has rejected the GE Hitachi Prism reactor is completely without foundation." He added that the current round of discussions "might last about six months". _Guardian
Current commercial nuclear reactors generate large amounts of so-called nuclear waste, which is actually extremely valuable nuclear fuel. Advanced generations of nuclear reactors will be able to burn this "waste" as an integral part of their fuel.
If the material we have seen until now as waste is instead seen as fuel, it has the potential to solve three problems at once: the UK's contribution to climate change, possible future energy shortfalls and a significant component of the massive bill - and massive headache - associated with cleaning up the current nuclear mess.

The technology with the potential to solve these problems is the fast reactor, ideally the integral fast reactor (IFR), which I wrote about in December. It exploits the fact that conventional nuclear power plants use just 0.6% of the energy contained in the uranium that fuels them. IFRs, once loaded with nuclear waste, can, in principle, keep recycling it until only a small fraction remains, producing energy as they do so.

The remaining waste is both unusable for anyone who might hope to make a weapon from it and presents much less of a long-term management problem, as its components have half-lives of tens, not millions, of years. An IFR plant could melt down only by breaking the laws of physics: if the fuel pins begin to overheat, they expand, stopping the fission reaction.

GE Hitachi has offered to build a fast reactor to consume the plutonium stockpile at Sellafield, though not yet the whole kit (the integral fast reactor). It has offered to do it within five years, and to carry the cost if it doesn't work out. This is the proposal the government is now considering. I would like to see it go further and examine the case for the full works: an integral fast reactor (incorporating a reprocessing plant) that generates much more energy from the waste pile. _G.Monbiot
Monbiot is a curious example of the growing number of leftist greens who have adopted advanced nuclear energy as a viable path forward for human civilisations. While still believing in the orthodoxy of carbon hysteria, such pro-nuclear greens have seemingly rejected the "dieoff.orgiasm" of their brother and sister greens.

As for the integral fast reactor which Monbiot mentions, it is an idea that needs to be developed and put into commercial use as soon as safely possible. A well-planned and phased move from light water reactors to integral fast reactors, molten salt thorium reactors, and gas cooled reactors -- at all scales from the MW to the GW ranges -- would provide a safe and solid energy foundation under future societies and civilisations.

Wikipedia Integral Fast Reactor


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Blogger Dick said...

“Some discussion about nuclear power is needed. Fourth generation nuclear power has the potential to provide safe base-load electric power with negligible CO2 emissions.

There is about a million times more energy available in the nucleus, compared with the chemical energy of molecules exploited in fossil fuel burning. In today’s nuclear (fission) reactors, neutrons cause a nucleus to fission, releasing energy as well as additional neutrons that sustain the reaction. The additional neutrons are ‘born’ with a great deal of energy and are called ‘fast’ neutrons. Further reactions are more likely if these neutrons are slowed by collisions with non-absorbing materials, thus becoming ‘thermal’ or slow neutrons.

All nuclear plants in the United States today are Light Water Reactors (LWRs), using ordinary water (as opposed to ‘heavy water’) to slow the neutrons and cool the reactor. Uranium is the fuel in all of these power plants. One basic problem with this approach is that more than 99% of the uranium fuel ends up ‘unburned’ (not fissioned). In addition to ‘throwing away’ most of the potential energy, the long-lived nuclear wastes (plutonium, americium, curium, etc.) require geologic isolation in repositories such as Yucca Mountain.

3:22 PM  
Blogger Dick said...

There are two compelling alternatives to address these issues, both of which will be needed in the future. The first is to build reactors that keep the neutrons ‘fast’ during the fission reactions. These fast reactors can completely ‘burn’ the uranium. Moreover, they can burn existing long-lived nuclear waste, producing a small volume of waste with half-life of only decades, thus largely solving the long-term nuclear waste problem.

The other compelling alternative is to use thorium as the fuel in thermal reactors. Thorium can be used in ways that practically eliminate buildup of long-lived nuclear waste.

The United States chose the LWR development path in the 1950s for civilian nuclear power because research and development had already been done by the Navy, and it thus presented the shortest time-to-market of reactor concepts then under consideration. Little emphasis was given to the issues of nuclear waste. Today the situation is very different. If nuclear energy is to be used widely to replace coal, in the United States and/or the developing world, issues of waste, safety, and proliferation become paramount.

3:23 PM  
Blogger Dick said...

Nuclear power plants being built today, or in advanced stages of planning, in the United States, Europe, China and other places, are just improved LWRs. They have simplified operations and added safety features, but they are still fundamentally the same type, produce copious nuclear waste, and continue to be costly. It seems likely that they will only permit nuclear power to continue to play a role comparable to that which it plays now.

Both fast and thorium reactors were discussed at our November workshop. The Integral Fast Reactor (IFR) concept was developed at Argonne National Laboratory and it has been built and tested at the Idaho National Laboratory. IFRs keep neutrons ‘fast’ by using liquid sodium metal as a coolant instead of water. They also make fuel processing easier by using a metallic solid fuel form. IFRs can burn existing nuclear waste and surplus weapons-grade uranium and plutonium, making electrical power in the process. All fuel reprocessing is done within the reactor facility (hence the name ‘integral’) and many enhanced safety features are included and have been tested, such as the ability to shut down safely under even severe accident scenarios.

The Liquid-Fluoride Thorium Reactor (LFTR) is a thorium reactor concept that uses a chemically-stable fluoride salt for the medium in which nuclear reactions take place. This fuel form yields flexibility of operation and eliminates the need to fabricate fuel elements. This feature solves most concerns that have prevented thorium from being used in solid-fueled reactors. The fluid fuel in LFTR is also easy to process and to separate useful fission products, both stable and radioactive. LFTR also has the potential to destroy existing nuclear waste, albeit with less efficiency than in a fast reactor such as IFR.

3:24 PM  
Blogger Dick said...

Both IFR and LFTR operate at low pressure and high temperatures, unlike today’s LWR’s. Operation at low pressures alleviates much of the accident risk with LWR. Higher temperatures enable more of the reactor heat to be converted to electricity (40% in IFR, 50% in LFTR vs 35% in LWR). Both IFR and LFTR have the potential to be air-cooled and to use waste heat for desalinating water.

Both IFR and LFTR are 100-300 times more fuel efficient than LWRs. In addition to solving the nuclear waste problem, they can operate for several centuries using only uranium and thorium that has already been mined. Thus they eliminate the criticism that mining for nuclear fuel will use fossil fuels and add to the greenhouse effect.

The Obama campaign, properly in my opinion, opposed the Yucca Mountain nuclear repository. Indeed, there is a far more effective way to use the $25 billion collected from utilities over the past 40 years to deal with waste disposal. This fund should be used to develop fast reactors that consume nuclear waste, and thorium reactors to prevent the creation of new long-lived nuclear waste. By law the federal government must take responsibility for existing spent nuclear fuel, so inaction is not an option. Accelerated development of fast and thorium reactors will allow the US to fulfill its obligations to dispose of the nuclear waste, and open up a source of carbon-free energy that can last centuries, even millenia.

3:24 PM  
Blogger Dick said...

It is commonly assumed that 4th generation nuclear power will not be ready before 2030. That is a safe assumption under ‘business-as-usual’. However, given high priority it is likely that it could be available sooner. It is specious to argue that R&D on 4th generation nuclear power does not deserve support because energy efficiency and renewable energies may be able to satisfy all United States electrical energy needs. Who stands ready to ensure that energy needs of China and India will be entirely met by efficiency and renewables?

China and India have strong incentives to achieve pollution-free skies as well as avert dangerous climate change. The United States, even if efficiency and renewables can satisfy its energy needs (considered unlikely be many energy experts), needs to deal with its large piles of nuclear waste, which have lifetime exceeding 10,000 years. Development of the first large 4th generation nuclear plants may proceed most rapidly if carried out in China or India (or South Korea, which has a significant R&D program), with the full technical cooperation of the United States and/or Europe. Such cooperation would make it much easier to achieve agreements for reducing greenhouse gases.

Prompt development of safe 4th generation nuclear power is needed to allow energy options for countries such as China and India, and for countries in the West in the event that energy efficiency and renewable energies cannot satisfy all energy requirements.

3:25 PM  
Blogger Dick said...

Deployment of 4th generation nuclear power can be hastened via cooperation with China, India and other countries. It is essential that dogmatic ‘environmentalists,’ opposed to all nuclear power, not be allowed to delay the R&D on 4th generation nuclear power. Thus it is desirable to avoid appointing to key energy positions persons with a history of opposition to nuclear power development. Of course, deployment of nuclear power is an option, and some countries or regions may prefer to rely entirely on other energy sources, but opponents of nuclear power should not be allowed to deny that option to everyone.”
— James Hansen

Let's forge alliances and make movements where we can, Al Fin, all while remembering that science is an inherently skeptical enterprise ;).

3:25 PM  

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