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Forgotten reactor Some years ago a research worker was presenting a paper at a conference in which she claimed to have achieved a new record of fuel irradiation in a fast reactor. But the same week there had been an announcement that development work on fast reactors was to cease. She reflected gloomily that her years of work would now be consigned to a dusty report which would probably never be referred to again. If in the future we were to build some more fast reactors the chances were that licensing bodies would require new irradiation experiments. There are many other fields where a similar glum future is in prospect. We could mention organic cooled reactors, molten salt reactors and even high temperature gas cooled reactors for starters. So at the risk of telling some people a rather familiar storey we give a brief summary of fast reactor developments before it is forgotten.
What is a fast reactor? It is one that makes use of the neutrons from fission of uranium or plutonium at the high energy at which they are emitted. These are fast neutrons and not clouds of neutrons that have been slowed down by a moderator to low, thermal, energies.
To achieve a fast neutron chain reaction one needs to increase the enrichment of uranium- 235 in the reactor or to use plutonium which has been produced by neutron bombardment of uranium-238. There are still some neutrons, known as delayed neutrons, coming from the short lived decay of fission products. This few seconds of delay makes it possible to control the reactor.
In the early days of nuclear power development before we discovered vast amounts of uranium in the ground, it looked as if we would need fast reactors to produce energy from the more abundant uranium-238. Also the proposed sodium coolant used in most fast reactor designs would be a better match with the prevailing steam conditions needed to drive electric turbines. It was an experimental fast reactor which produced the first electricity from nuclear power to light a bulb.
The liquid metal coolant, sodium, presented challenges but in the end proved very amenable. It is true that it burns spontaneously in contact with air but it is only a smouldering type of fire at the surface of the material. Practices were developed for extinguishing sodium fires – the French built a large experimental facility in which they could drop large quantities of sodium on the floor. The sodium also reacts rather violently with water so an intermediate non-radioactive circuit was introduced between the primary coolant circuit and the steam circuit driving a turbine. This was one of the main reasons for a rather higher capital cost for fast reactors.
In working out the economics it was assessed that the price of uranium would have to be a lot higher for the fast reactor to be competitive with thermal reactors. But wait a minute. We have all the uranium we need stored safely at Capenhurst in Cheshire. It is estimated to have the energy equivalent of the countries entire coal resources. It does not have to be mined, it is ready to use. It is called a waste by the uninformed.Why on Earth do we not use it.
You also need some enriched uranium or plutonium fuel to drive the reactor core.Again we have it. Sitting safely in store at Sellafield there is nearly 100 tonnes of plutonium separated from the reprocessing of Magnox used fuel. If only we still had a fast reactor we could run it for a lifetime at zero fuel cost.
Fast reactors were still being developed around the world. But then America cancelled a half built prototype at Clinch River because of silly scaremongering by opponents about a so called “plutonium economy” and supposed proliferation risks.
Originally the fast reactor was hailed as one which would produce more plutonium fuel from uranium-238 than it was consuming in its core. This feature was known as breeding.
But the breeding ratio was only just over one times and could easily be avoided. So now we talk simply of “fast reactors” instead of “fast breeder reactors.”
France, Britain and the Soviet Union built and operated very successful prototype fast reactors producing in the range of 250 MWe to 350 MWe. The Soviet Union went on to produce a 600 MWe fast reactor which is still operating very well.
The French, in partnership with the Germans and Italians, also built a 1200MWe plant, Superphenix, which was a magnificent work of advanced engineering. It was completed at a site called Creys Malville to the northeast of Lyon in France. But when it was just about at its design power it had a few early teething problems. The French government of the time decided that they did not like it and cancelled the project. This was a scandalous waste of the huge expense of the project and could not possibly be justified.
They continued to operate the smaller 250MWe fast reactor, Phenix, for a few years but that has now been stopped as has the 250 MWe prototype fast reactor at Dounreay in Britain. The Germans also built a fine 300MWe prototype fast reactor but pulled it down again before it produced any power.
Japan has a prototype fast reactor, Monju, which has operated but suffered a leak in its intermediate coolant loop and was closed down for years while it was investigated. It is just now restarting.
India is slowly building a 250 MWe fast reactor and this will be interesting because it will produce uranium-233 fuel from thorium and open up the possibility of a new fuel cycle.
Russia has plans to complete the building of an 800 MWe fast reactor but keeps on running out of money. It looks as if it will eventually be completed but it is a slow process.
Before the British opted out they had joined with other European partners on the design of a 1200 MWe commercial fast reactor but this has since been consigned a dusty shelf.
There are several fast reactor concepts included in projects under study by an American led international team looking at fourth generation plants but these are many years away from any building of a power producing reactor.
Oh! And to complete the picture, China is building a small fast reactor.
Looking at the World picture, one has to say that prospects for fast reactor developments are not bright. Yet ultimately we will need them to take up the option of vast amounts of clean, safe, energy from stockpiles of depleted uranium. It is true that a year or two ago they looked to be very expensive but at today’s prices they could be becoming interesting and should certainly not be put on a dusty shelf.
Monju back at least Following a ruling by the Supreme Court of Japan back in May 2005 a programme of modification has been completed on theMonju fast reactor and the plant was restarted by the Japan Atomic Energy Agency on the 6 May. This is after a long shutdown since December 1995 when a leak occurred in the intermediate sodium coolant circuit. The incredibly long shut down is the pattern of things in Japan after any nuclear incident. The plant has been assessed and re-assessed in excruciating detail and legal battles have been fought to resurrect an essential part of the Japanese nuclear programme.
Monju is a 250 MWe plant with a sodium cooled reactor. It is a loop design with the circulation pumps and heat exchanger located in cells around the reactor and further cells for components of the intermediate loop and finally sodium steam heat exchangers. This differs from French and Russian designs - the only other operating fast reactors producing electricity - which have the whole of the primary circuit in a pool of sodium along with the reactor core. Both designs are quite valid but the loop system is said to allow greater attention to be paid to the different sections. In any case it is good to see another fast reactor operating.
Russian people have righ idea Nearly half of Russians in a recent poll (42.6%) could see no alternative to nuclear as an energy source. Other sources had only a small number of supporters. Hydro power had 15.7% support, coal was down to 7.9% and only 6.5% considered other types of generation such as wind.
A mere 4.6% supported the idea of a complete abandonment of nuclear energy while 37.2% supported the current level of nuclear deployment and 36.9% were in favour of active development. These figures represent a slight increase in support since a similar poll in 2009 and a decrease in opposition. InApril 2009 there was 4.7% support for complete abandonment and 11.6% interested in phase out while 69.5% supported further development.
ITER staggers on Kaname Ikeda, addressing participants at the Financial Times Energy Challenges conference in Brussels said: “ITER is not an electricity producing machine, it is experimental, but we are confident we can build this machine, and show that fusion is technologically feasible.”
Well we told you that back in July 2005 when the International Thermonuclear Experimental Reactor (ITER) project finally announced that they were going ahead with a 500 MWth design at Cadarache. This was a scaled down version of the 1500 MWth machine which had originally been proposed by the French designer of JET, Henri Rebut.
It was scaled down because the US was opting out. They are now back in the project (we think) together with Russia, China, India, Japan, Canada, and the whole of the European Union. Surely they could have told the Americans that their contribution was irrelevant.
Now the project head, Ikeda, is saying that they will need another 10 years – we are not quite sure when from – to build an electricity producing demonstration plant.
It used to be claimed that once fusion achieved break even – the energy out is greater than that being pumped in – the commercial exploitation would happen more quickly than it did after the first demonstration of fission. Unfortunately the record does not show so. It took just four years from the first fission chain reaction in a Chicago pile to large plutonium producing reactors and only a few more to production of electricity. Fusion on the other hand was demonstrated with a 16 MWth burst for a few seconds back in 1998 and we are only now just starting to build a 500 MWth reactor which may begin operation in about 2016. And then another ten years to electricity production?
But it is unkind to knock fusion too hard. It is lovely engineering. It started back in the early 1960s with electric discharges that demonstrated a pinch effect of plasma compressing down quickly and becoming very hot. Then a British development that showed that by bending the plasma round into a doughnut shape and inducing the discharge magnetically you could get rid of end losses. This was the Zeta experiment at Harwell and produced the first claim of fusion power in ten years time. Unfortunately they had been over optimistic. They were still having problems with the instability of the electric discharge. The Russians finally overcame this by applying brute force magnetic fields in a Tokamak. The largest Tokamak so far is the JET machine operated at Culham in the UK by the European Union and this finally produced about a seconds of fusion when tritium was introduced as one of the fuels in 1997. A major development over the past years had been systems to heat the plasma. Neutral particles – neutrons – were fired in and also electromagnetic radiation was directed in. But a further scaling up in size was needed. There was also a lot of development of a diverter system to bleed of a bit of the plasma and clean out the fusion products.
Another feature of the ITER design is the inclusion of a cryogenic blanket round the magnets to allow superconductivity and much higher magnetic fields. This is the technology used for a 27 km ring of magnets under the Swiss-French border at CERN which, after early teething problems, has been operating well. A French machine, Tore Supra, has also been using super conducting magnets for some years.
The only major problem left is to get energy out of a fusion reactor once it is operating.
What is proposed is to surround the machine with a blanket of lithium in which neutrons escaping from the machine will breed more tritium fuel. The neutrons will carry a lot of heat energy which will be captured by a liquid metal – sodium – coolant and pass to steam generators and an electric turbine like a fast reactor (see earlier report). Contrary to popular belief, a fast reactor does not produce vast amounts of fission product waste. It recycles the fuel in uranium and can burn up fission products. So the fusion engineers ought to be able to work together to help them get power from their machine.
The latest IAEA Bulitin arrived There was an article on closing the cycle so we read it eager to see support for recycle.
Well there was no mention of reprocessing technology which has been going on at a commercial level in France and the UK for years and is just starting in Japan. Spent fuel is discussed as if it is waste rather than recycleable nuclear fuel. Licensing developments in Sweden, Finland and the US for waste repositories were featured although there is a footnote indicating political difficulties that have arisen in theUSwith licensing Yucca Mountain.
One useful figure presented by the International Atomic Energy Agency is that about 86% of high level waste is from military development programmes in the US and Soviet Union – thankfully now ended. That was a problem but not one that should be put at the door of the peaceful uses of nuclear energy.
If we go on so much about waste disposal people will begin to think that we really do have a problem. But in recycle of MOX and later uranium-238 in fast reactors we have a perfectly acceptable solution. And this way it is not necessary to be talking about repositories that will be safe for thousands of years. In 100 to 300 years all the waste will have decayed to a lower level of radioactivity than the uranium dug out of the ground in the first place.
Hulme will not vote against it Chris Hulme, the new Social Democrat minister for energy is said to be opposed to new nuclear building but he has indicated that as long as the government is not called on for money the industry can go ahead with the normal planning permission without his objection. This sounds OK. The plans of Electricite de France and E.ON and RWE from Germany should not require any money but they could do with a bit of a shove to get them moving.And what a disgraceful lack of interest is the government showing in what could be the most important investment in our future. But so be it. Let them sit back and watch French and German engineers get on with the vital task of ensuring Britain’s supply of electricity.
Just so we have the quote on record here is his statement on the BBC. He said: "If the industry comes up with a plan which genuinely involves no public subsidy, then it will go through the normal national planning process and the proposal will go forward in the normal way and we are committed in the Liberal Democrat side of the coalition not to vote against it.”
Animal farm energies It now seems that while all non-carbon emitting forms of energy are equal, some are more equal than others. The concept of charging a carbon price for emissions of carbon dioxide in an attempt to reduce the global warming potential of electricity generation was intended to make burning fossil fuels more expensive and thus favour non-fossil fuels. To the horror of some they have now realised that while a high carbon price will benefit the renewable energies it will also benefit nuclear power.
While it is for them acceptable, indeed desirable, that the inefficient, intermittent wind, wave, and solar plants should be subsidised, they insist that all new nuclear plants must be built without any form of subsidy. In this they are caught on their own misleading beliefs that this will stop any new nuclear construction. The claim of the Guardian that “Nowhere in the world are nuclear stations being built without massive state subsidies…” is just not true.While their inevitable reference to the £7.3 billion budget of the Nuclear Decommissioning Authority ignores the fact that most of this is related to the nuclear weapons programme from the 1940s onward and has little to do with any new nuclear power stations.And now, with the acceptance that spent fuel, the so-called nuclear waste of the once-through fuel cycles, can be reused as nuclear fuel in advanced reactors, the killer question of “ but what about the waste?” has lost its force.
If we are serious about reducing carbon emissions a high and stable carbon price is desirable, preferably through a carbon tax rather than through an inefficient and unstable carbon market. That this will also benefit nuclear power, a reliable and efficient electricity source, to give an increased energy independence and a reduced reliance on energy imports should be welcomed.
Concentrated and diffuse energies Nuclear fission is a highly concentrated form of energy. In a nuclear power reactor large quantities of energy are generated from very small amounts of material. Wind and most other renewable energies are diffuse. Large numbers of wind turbines are required as each can only collect a small amount of energy and that only when the wind blowing at the appropriate speed. This much is obvious and well known, but a simple calculation with some actual figures shows such a remarkable difference that it is difficult to understand how wind power can be seriously considered as an energy form for a mature industrial society.
The draft nuclear paper from the previous government listed ten potential sites for new nuclear stations. If a 1500MWstation is built on each site, they would together if operating at 7000 hours a year (80% load factor ) generate 105,000,000 MWh of electricity each 17 520MWh. The ten nuclear stations would be equivalent to 6000 offshore wind turbines.
There is a further difference. The nuclear stations can be expected to operate for 60 years. The wind turbines for perhaps 20 years. It would then require some 18 000 wind tubines to replace 10 nuclear stations. To build and operate 10 nuclear stations would be a feasible task; the electricity they produce could be readily fed into the national grid.
To build 18 000 wind turbines around our coasts and in the North Sea would be a monumental task, their maintenance a nightmare and the collection of the electricity they produce and bringing it ashore extremely costly.
A biodiversity report from the UN warns of the damage to the natural world from the growth of the global economy. It suggests that 85%of the oceans have been damaged. The North Sea is already being exploited for its oil and gas reserves. The emplacement of 1000’s of wind turbines in these waters would further increase the industrialisation of this natural environment. In contrast the ten nuclear stations would be built on existing nuclear sites causing a minimum of local disturbance. The need for electricity will continue to increase. Environmental concerns demand that it should be generated from the most concentrated sources. Diffuse renewable energies are not the answer.
Iran Iran would seem to be an exception to President Sarkozy’s call for a wider access of all countries to nuclear technologies. This arises from the widely held belief that Iran’s enrichment programme is primarily intended for a nuclear weapons rather than for power.
But this makes American calls on Russia to delay the start-up of the Bushire reactors - which would safely place most of Iran’s low enriched uranium inside a reactor - illogical.
While there are now deeply held suspicions on both sides, history shows that Iran has good reasons to mistrust assurances from the West on the supply of nuclear fuel and to rely on its own capacity. Before imposing new sanctions on Iran theWest should consider that the outcome of such measures may be the opposite of what is intended. This can be seen from a brief review of the nuclear developments in Iran.
The late Shah was far-sighted enough to foresee the need for nuclear power even though Iran had large reserves of oil - a need now recognised by the UnitedArab Emirates which has ordered four nuclear stations from South Korea, and which is actively being contemplated by other Gulf states and Saudi Arabia.
Nuclear research began at the University of Tehran in 1956 and Iran became a member of the IAEA in 1958. It acceded to the Non-Proliferation Treaty in 1970. These moves were encouraged and supported by the USA which supplied Iran with kilogramme quantities of enriched uranium and plutonium as well as a small research reactor. A proposed programme for 23 000 MWe of nuclear power was seen as offering important export contracts to American, British, French and German companies. As an initial step two 1300 MWe stations were ordered in 1974 from KWU to be built at Bushire. France was to build a further two stations. In 1975 the US offered Iran a $6.4 billion loan for another eight stations. Iran was seen as a substantial new nuclear market and the head of year. An offshore wind turbine of 5MW operating at 40% load factor would generate the Iranian Atomic Energy Organisation, Akbar Etemand was courted as a key figure by Western companies.
A substantial nuclear programme such as was then being considered by Iran needs an assured supply of enriched uranium fuel. To secure this Iran, in 1974, took a 10% share in the French Eurodif enrichment plant with a loan of $1 billion in return for the right to 10% of the production.
All these activities were brought to an end by the Islamic revolution in 1979 and all contracts halted. France has refused to supply any enriched uranium even though Iran still owns 10% of Eurodif (through a 40% share together with Cogema in Sofidif which owns 25%of Eurodif). It is also unclear whether or not the $1 billion loan has been repaid (one report of Nov 2009 claims that despite repeated requests from Iran, it has not). The French are also said to be liable for a contract under which they were to deliver 50 tons of gaseous uranium hexafluoride (UF6) to Iran. On the German side RWE withdrew from the Bushire project and although Iran negotiated for this to be taken over by Russia, for another $1 billion payment, the construction of these reactors is only now, after 15 years, approaching completion.
Given this history it is not surprising that Iran should now seek to develop an independent uranium enrichment capacity. This would not have been necessary if the paid and contracted-for supply from France had been available.
Iran is also suspicious of proposals that it should send its own low enriched product to Russia for enrichment up to the 20% needed to fuel a research reactor producing medical isotopes. In view of past history its fears that, if it were to send most of its present stock of low-enriched uranium abroad for enrichment up to 20% there is no guarantee that it would eventually be returned, are not without foundation. Iran has now informed the IAEA of its intention to do this itself - as it is entitled to do under the NPT - and under the eye of the IAEA inspectors.
It is not possible to hold back the scientific and industrial achievements of a country such as Iran which will seek to develop its own capabilities if imports are prohibited. As an example Iran is now holding an exhibition of Laser Science and Technology Achievements. Laser enrichment of uranium is now seen as a future process now underdevelopment in the USA and Australia. In another area of advancing technology Iran now claims it is producing 97 percent of the prescribed and non-prescribed medicine needed in the country. Sanctions can have the opposite effect to what they are intended to achieve.
Iran’s need for nuclear power cannot be disputed. Between 1967 and 2005 the population has increased by a factor of almost three and over the same time the average household consumption of electricity has increased by a factor of four.
Contrary to the American call for Bushire to be delayed the West should encourage and assist Iran (and any other potential proliferator) to increase its civil nuclear capacity. The more fissile material is safely inside a reactor generating much needed electricity the less is available for weapons. |
