Armin Tenner

Development of Nuclear Energy [1]

Introduction

There is a worldwide new development, named ?nuclear renaissance." After many years of moderate investments in nuclear reactor projects or even decommissioning, ambitious new projects are started in several countries. Nuclear energy production is mainly advocated to meet the growing energy consumption that is foreseen for the coming century and is recommended as an environmentally clean procedure, not leading to CO₂ emission. However, the development will have important and serious consequences for the future which we will discuss in the present article.

European situation

At the moment, the status of nuclear energy in Europe, where more than 300 reactors are in operation is confused. From the beginning of the nuclear age, anti-nuclear activists worked against existing reactors and the commission of new ones. The public reaction against the technology was strengthened by Chernobyl and by near-accidents like in Sweden where a reactor was at the edge of meltdown. The public resistance was successful in a number of cases and led to the decision in different countries to reduce the number of nuclear reactors. Spain and Germany took the decision for complete phase-out. Spain is in the favourable position of having developed already big solar-heat facilities and hopes to export this technique to the Sahara in the coming years. Germany decided to phase out all installations before 2020 and is bound to do it by the party agreement of the present government. Sweden closed several reactors after a continuation of accidents. On the other hand, the 59 reactors in France are still in full operation and new developments are in discussion and preparation. Other countries are building new power plants: Finland and Ukraine, and Russia plans to bring its nuclear energy production of 21.7 GWe per year to 4 times this value by 2050.

First dilemma

In Germany, terminating nuclear energy production creates a dilemma for the environmentalist community. The cut-off of nuclear energy must be compensated by burning coal and gas, the development of alternative energy sources being insufficient. Germany promoted the development of alternative energy production more than most other European countries, but now reaches the limit of the possibilities. As a result, the intended reduction of CO₂, set by the Kyoto agreement, becomes questionable if nuclear energy is eliminated.

Second dilemma

A second dilemma arises in connection with the nuclear disarmament. The Non Proliferation Treaty, NPT, became effective in 1970 and has since been ratified by 186 nations. Five of these countries were the officially recognized owners of nuclear weapons, who were allowed by the Treaty to keep and maintain their weapons; the others were forbidden to develop or achieve them forever. Nobody was allowed to transfer nuclear weapons or nuclear-weapon technology to any other country. This principle of non-proliferation is laid down in Article I and Article II of the Treaty.

In order to remove the imbalance between the nuclear weapon owners and the rest of the parties, the Nuclear-Weapon-States made the promise to reduce their weapon arsenals, finally to zero, so that all nuclear weapons in the world would be eliminated. This commitment is made by the Nuclear-Weapon-States in Article VI of the NPT:

Each of the Parties to the Treaty undertakes to pursue negotiations in good faith on effective measures relating to cessation of the nuclear arms race at an early date and to nuclear disarmament, and on a treaty on general and complete disarmament under strict and effective international control."

The NPT was extended at the NPT evaluation conference in 2000, by which the Nuclear-Weapon-States, although they had done little to fulfill their commitment in the preceding 25 years, reiterated their promise.

At the same time, the NPT grants all 186 parties of the NPT the right to develop and use nuclear energy for civil purposes. Article IV of the Treaty says:

"1. Nothing in this Treaty shall be interpreted as affecting the inalienable right of all the Parties to the Treaty to develop research, production and use of nuclear energy for peaceful purposes without discrimination and in conformity with Articles I and II of this Treaty.

2. All the Parties to the Treaty undertake to facilitate, and have the right to participate in, the fullest possible exchange of equipment, materials and scientific and technological information for the peaceful uses of nuclear energy. Parties to the Treaty in a position to do so shall also co-operate in contributing alone or together with other States or international organizations to the further development of the applications of nuclear energy for peaceful purposes, especially in the territories of non-nuclear-weapon States Party to the Treaty, with due consideration for the needs of the developing areas of the world."

In the years after 2000, by the political development, but primarily by the unwillingness of the United States, the NPT came in a very bad position, mainly because the US only wants to recognize the non-proliferation part of the Treaty and neglects or violates the other paragraphs. Since Article VI of the NPT is the only commitment for nuclear disarmament, ever made by the Nuclear-Weapon-States, promoters of nuclear abolition believe that the NPT must be saved and maintained in the future. This however means, that also article IV must be maintained, since it is the main reason for the 181 non-nuclear-weapon states to stay inside the NPT. This again, creates a dilemma for supporters of the abolition movement who may be opposed against nuclear energy.

 

International collaboration

The situation in Europe may be confused and unclear, on global scale, predominantly in Asia there is a movement for a strong expansion of nuclear energy technology and the arsenal of nuclear reactors. Arguments in favour are the expected growth of the power demand which is estimated by 2050 to be worldwide 60% above the present level (65% in Europe) and much larger in Asia, and the expected depletion of fossil-fuel supplies. In addition, new power demand is foreseen for the desalination of seawater in dry areas of the world. Egypt, Saudi Arabia, Morocco and Algeria have shown interest in developing nuclear power primarily for water desalination. The emission of greenhouse gases and their influence on the climate, by burning fossil fuels is always mentioned in this context. It is compelling to follow the trend of this a vast expansion of nuclear energy production to estimate the consequences for a future world.

In 2006, a collaboration has been established between India, Russia, China, France, Japan, South Korea and Ukraine for a new type of fast nuclear reactor with closed nuclear fuel cycle that should produce 300/500 GWe by 2050. The project is under the auspices of the INPRO, Innovative Nuclear Reactors and Fuel Cycle of the IAEA, the International Atomic Energy Agency. India is chair of the new collaboration; other countries might become members.

Fast means that the neutrons in the reactor are fast and not slowed down by a separate moderator. Closed nuclear fuel cycle means that the spent fuel of the reactor is subjected to reprocessing, at which the unburned uranium and the bred plutonium are extracted for further use. With this procedure, 97% of the spent fuel can be reused for fuel production, strongly reducing the need of uranium mining and separation. This reduction is compelling in view of the limited availability of high-quality uranium ore in the world. If the high-quality ore is exhausted, only ore with considerably less content of uranium will be available which needs an increasing amount of work and energy for milling the stone and purification. In the last 10 years, the price of uranium already went up by a factor 3 and the price will go further up with increasing depletion of the uranium ore.

The design of the new reactor will be subject to several requirements:

1. Safety ? people learned from Chernobyl and will build in safety against nuclear disasters into their design. The most important method will be the construction of reactors with a negative temperature coefficient of reactivity. When the temperature of the reactor rises, the energy production decreases, so that the temperature comes to a standstill.

2. Technology ? the high temperature at which the reactor is supposed to work will need special measures against corrosion of materials etc.

3. Non-proliferation ? it should be impossible or extremely difficult to use the products of the reactor for military purposes.

4. Environmental concerns ? part of this is implicit, since the reactor itself does not emit CO₂ and the mining of uranium and the energy consuming milling are reduced. Other environmental concerns are the release of cooling water etc.

5. Waste management.

6. Economy.

7. Infrastructure.

 

We will come back to these design conditions later, but one question may be asked here. If safety, waste management and environmental impact are optimized in the design, how will that work out when the number of reactors in the world becomes a multiple of what we have at the moment?

Since the countries in the collaboration all have their own far-reaching developments and projects, and the situation in these countries is different, it is questionable that one single design will come out of the collaboration?s effort.

Pebble-bed-reactor

With the great number of proposed nuclear reactors, it is interesting to discuss two prominent examples, different from the previous one. First the pebble-bed-reactor. It has been invented in Germany in the 50s of the previous century and worked as a test reactor in J?lich for more than 20 years. It is now in operation in China and in South Africa. The pebble-bed-reactor combines the reactor fuel with a carbon moderator. The pebbles are spherical pyrolithic-graphite bodies with a diameter of 6 cm, in which small patches of fuel, e.g. MOX, a mixture of plutonium and reprocessed uranium are dispersed. When 360,000 pebbles are packed together, the reactor becomes critical. Cooling is achieved by helium that immediately drives the turbine for electricity production. The heat can also directly be used for water desalination. Regularly, the pebbles are individually taken out at the bottom of the reactor and after inspection put back at the top or sent for reprocessing.

Let us check the previously mentioned design requirements.

The safety of the reactor is good; by its negative temperature coefficient it is self-controlling. When the temperature rises, the neutron energy distribution is widened and at its top more neutrons penetrate into the region in which they are captured by U238 which leads to plutonium production. The heat production of the reactor is throttled because of lack of low-energy neutrons that produce the fission. If the cooling of the reactor is stopped, the temperature rises from 900 to 1600 degrees, where the radiation to the outside world equals the heat production. The experiment has been carried out successfully at J?lich and has been demonstrated at the test reactor of Tsinghua University in Beijing for an international delegation of reactor experts. In the case of earthquakes or military attack, the reactor could be demolished and the carbon pebbles could catch fire. Therefore, they are coated with a silicon layer, but the risk of nuclear pollution still exists.

The technology is good, since the helium carries no radioactivity when leaving the reactor and entering the turbine and is not chemically aggressive. There is little radiation damage of materials that are in contact with the coolant. The helium has much higher temperature than the coolants in conventional reactors, so that the turbines work more efficiently. The temperature is sufficient to produce hydrogen from water.

The economy is good. There is no heat exchange equipment and limited corrosion damage; parts of the reactor can be produced in mass production. The reactor may become cheap.

The proliferation resistance of the pebble-bed-reactor is very bad. It is easy to put in a pebble made out of depleted uranium and after some time harvest weapon-grade plutonium at the bottom of the reactor. Or even better: Put in a pebble made out of thorium, as I will explain later. In view of the fact that these reactors may be produced in great number and installed at various remote places in the world, the danger of military application, clandestine or not, is serious.

China, which started late with its nuclear energy program is preparing for a vast expansion. Reactors and technology have been imported from Russia, France and Canada, but intensive research and development are done in China itself. China plans to increase its nuclear capacity to 40 GW by 2020, six times the present capacity, for which 30 new reactors are needed, and will deploy 150 1-GW power plants until 2050. The pebble-bed-reactor is one of the innovations. A 200 MW prototype should be completed by 2010 and before 2020, 30 reactors should be sold.

A similar 165 MWe reactor is being produced at Koeberg in South Africa. It is planned to install 10 reactors at the coast for water desalination and within a few years, 20 reactors per year should be on the international market. The production program fights against strong resistance of the South-African population.

Breeding reactors

An important development is the resurrection of the breeding reactor. Breeding reactors produce plutonium, or recently of U233, more than they consume, so that their output can be used for further operation of the reactor, for other reactors or for military purposes. In the past, most breeders were decommissioned e.g. in France (Bugey) and Germany (Kalkar), because of failures and under the pressure of the public opinion. However, a main argument for terminating the development has always been the high price of the produced fuel in comparison with fresh uranium used for conventional reactors. This market-economy argument will become obsolete when the uranium prices are further increasing. At this moment, an 800 MWe breeder is working at Beloyarsk in Russia and the 280 MWe Monju breeder in Japan is in preparation. In addition, a breeding reactor works in the UK and France is interested in a new development.

India has an indigenous nuclear power program and conducted extensive research, under the pressure of the international embargo for its unwillingness to sign the NPT. It has 16 nuclear reactors in operation, mostly pressurized heavy water reactors, working with indigenous natural uranium as a fuel. Some uranium has been imported, e.g. from Russia. The programmed extension of the power production should lead from the present 3.5 GWe to 20 GWe by 2020 and possibly 300 GWe by the middle of the century. The indigenous uranium reserve of India amounts to 1% of the world?s total which is not sufficient for supporting the planned nuclear capacity with a conventional regime. Therefore, India is one of the strongest promoters of the development of a closed nuclear fuel cycle, and has conducted intensive research in this field. In addition, India makes progress in the development of breeding reactors, in order to be able to produce new fissile material. With breeding and reprocessing, a factor 50 is expected in the increase of fissile material efficiency.

In Kalpakkam, near Madras, a 500 MWe fast breeding reactor is under construction and will be completed by 2010. In addition, 3 of these reactors will be installed before 2020 and participate in the electricity production. The new reactor will be fuelled by a mixture of 25% plutonium- and 75% reprocessed-uranium oxides, the plutonium being obtained from the existing heavy water reactors. The reactor core, containing 2 tonnes of plutonium, is surrounded by a blanket, containing U238 which leads to plutonium production by the irradiation with the fast neutrons of the core. There is no separate moderator. The reactor is cooled with liquid sodium. The plutonium may be harvested from the blanket and reprocessed from the reactor core.

In the next stage, thorium comes in. Where India has only 1% of the world?s uranium reserves, it has 25 ? 35% of the thorium. Worldwide, thorium is three times more abundant than uranium. Like U238, thorium is not a fissile material, but it can be transmuted into U233 which is fissile (see figure). In order to fuel its reactors in the long term, India concentrates on the utilization of its thorium supplies. It is envisaged that the Kalpakkam breeder will already contain an additional thorium blanket.

The first pure thorium breeder will be fuelled with the plutonium that has been obtained from the existing heavy water reactors. Once U233 has been obtained, it may be used as a core material, so that finally the reactor is running on thorium alone. Then, U233 will also be used for energy production in heavy water reactors.

The thorium breeder produces half the waste of a uranium-fuelled reactor. In a conventional reactor, transmutation of U238 leads to plutonium, the isotopes Pu239, 240, 241, 242 and other transuranic elements like curium and neptunium. The long lifetime of these isotopes makes that the waste will be active over hundreds of years, in contrast with the radioactive fission products which live much shorter. The lighter U233 will be partly transmuted into U234 by neutron capture or loose two neutrons by the absorption of one and pass into U232. No transuranics will be produced.

 

 

The US-India agreement

Recently, the United States and India concluded an agreement about nuclear collaboration. India has not signed the Non-Proliferation Treaty and is in the possession of nuclear weapons. According to the deal, the civil branch of the Indian nuclear program will be supported by the US, among others by delivering nuclear reactors to India which, together with the existing civil reactors, will be put under strong safeguarding of the International Atomic Energy Agency, in order to prevent them from being used for nuclear weapon building. The BARC complex in Trombay (Weapons Research + Reactor Research) and MAPS complex (Reactor Research + Weapons Research) in Kalpakkam, with their reactors, stay outside the agreement and may freely be used for military purposes. The agreement has been approved by the US Congress, but it is still questionable whether it will come into force. It has still to be approved by the Nuclear Suppliers Group which consists of 45 state members, part of whom are strongly opposed against the deal. A crucial point is that India, during the negotiations, managed in keeping out the breeders from the IAEA safeguarding, implicitly conceding that they will be used for further weapon production. The US had to accept the Indian standpoint.

The military capacity of the proposed Kalpakkam breeder is impressive. The extraction of plutonium from the deleted-uranium blanket yields weapon-grade material, provided the blanket is taken out from the reactor and renewed before appreciable quantities of the higher plutonium isotopes could be formed. The reactor acts as a laundry, transforming reactor-grade plutonium in the core into weapon-grade plutonium in the blanket. In addition, the uranium will be extracted from the thorium blanket and yields weapon-grade U233. [2] Consuming one tonne of reactor-grade plutonium per year, the breeder may produce hundreds of atomic weapons in a couple of years.

Dangers

1.A danger of the described development will be that in spite of the fact that reactors become technically safer, the increase in number all-over the world may cause more accidents. A general application of the closed fuel cycle will lead to more reprocessing centers. The continuous transportation of spent and reprocessed fuel between the reactors and the centers ? often over long distances ? will increase the probability of accidents, theft and robbery.
The continuous manipulation of highly radioactive materials in the centers will cause health damage of the personnel and the population in the environment of the installation.

2. ?The installation of small reactors for desalination and local energy production give rise to an increased risk on accidents and clandestine Pu239 and U233 production.

3. The production of Pu239 and U233 in many more reactors will make these isotopes more abundant in the world and easier to obtain by states and military factions.

4. Less technical skill is needed for the production of a U233 weapon than for a plutonium bomb, opening new opportunities in countries with modest technical facilities.

5. The production of weapon-grade material will be facilitated by the development of breeder reactors and by the separation made between civil and military applications, as demonstrated in India at the moment. The breeder reactors will produce weapon-grade isotopes, even if these are not intended for military use. Safeguarding by official institutions will become more complex and difficult. .

6. In an MIT study The future of Nuclear Power[3], the authors declare: ?We have not found and, based on current knowledge, do not believe it is realistic to expect that there are new reactor and fuel cycle technologies that simultaneously overcome the problems of cost, safety, waste, and proliferation."

7. International conflicts like in Iran, will become more abundant and more serious and a new weapon race is a distant prospect, in which old and new Nuclear-Weapon-States will participate.

 

Conclusion

In the past, the threat of nuclear war, radioactive contamination, climate change and the coming need of fresh water provision seemed to be separate items on the list of problems that should be solved by humanity. These problems are intertwined in the era of nuclear renaissance and cannot be solved separately. Solution of all problems together will need new strategies in the connected fields.

 

armin.tenner@xs4all.nl