Università di Pisa, October 15-16, 2001

We are meeting here to commemorate the hundredth anniversary of the birthday of Enrico Fermi, whose memory will for sure be kept by history as one of the greatest men of the twentieth century. He was not only a foremost scientist, with the unique ability to rank among the first both as a theorician and an experimental physicist. He was always interested in the technical applications of science, and he deserves to be celebrated as the father of nuclear energy.

When he died, nuclear energy was in a state of euphoria. Shortly before, President Eisenhower had taken the "Atoms for peace" initiative, which led to the first Geneva conference organized by the United Nations in the Summer of 1955. The use of nuclear energy for civilian purposes was then taking shape in several countries and there was a quasi universal consensus that this new kind of energy offered bright prospects to meet the growing energy needs of mankind.

Now, almost half a century later, the outlook has drastically changed. In many places, and notably in industrialized countries, a large number of people are reluctant, if not strongly opposed, to have recourse to nuclear energy. Several countries have indeed banned its use.

In my present paper I will not dwell on the various causes and the many facets of this situation. My purpose is to discuss the main issues raised by a wide-spread peaceful use of nuclear power. I distributed them under four headings, which will be examined in succession. The first three, namely economics, safety and health protection, and defence of the environment, are of a general nature, as they apply to any kind of technology. To those must be added, in the particular field of nuclear power, a specific matter, concerning its possible links with the proliferation of nuclear weapons.

Public acceptance is of course a major condition for nuclear energy to be deployed in a democratic society. This extremely important topics has multiple bearings and deserves to be dealt with on its own. Though I will on occasion refer to it, I did not include it in a systematic way within the scope of the present paper.

The criminal attacks perpetrated by terrorist groups against the US on September 11, 2001, constitute a dramatic new fact which will upset lastingly the conditions and the frame of our daily life. It will certainly have in all fields deep consequences, without anybody being yet able to imagine all its implications. Nuclear energy will not keep out of a number of questions which it will raise. It is of course too early to discuss them thoroughly. I will only present a few preliminary reflections in that respect.

The main reason why the deployment of nuclear energy in the United States came to an abrupt stop a quarter of a century ago is to be found in economic considerations. For many decades, thanks to the availability of large domestic deposits of cheap coal, gas and oil, conventional power plants burning fossil fuels were truly unbeatable. Nuclear reactors designed at an early stage of development suffered from their high capital costs. Utilities became increasingly concerned about the financial consequences of safety regulations evolving in a way impossible to foresee. The TMI accident, in 1979, which had a great impact in the US, though it caused no casualties, could only make the overall picture worse. For the electricity producers it highlighted the financial risks incurred in case of a severe accident.

Over the years the situation has changed. Owing to a remarkable effort of American industry, the capacity factor of nuclear power plants in the US has grown steadily, approaching now 90% on an average, which means one of the highest in the world. Great progress was accomplished to increase the burn-up of the nuclear fuel, resulting in a better use of it and shorter interruptions for refueling. Operation and maintenance costs have drastically improved in recent years.

While maintaining a strict control on the safety of nuclear installations, the NRC became much more responsive to the legitimate concerns of the producers and ready to cooperate to find the best solutions to the technical problems encountered. By agreeing to extend in principle the lifetime of a number of nuclear power reactors up to sixty years, and to grant operating licences applying to a generic system of plants, it made long-term planning easier.

Of course major progress has also taken place on conventional power plants. Yet the measures required for reducing the release into the atmosphere of SO2, NOx, etc,¼ , induced significant increases in the KWh cost.

Whatever the reasons, the result is that many American nuclear plants, a number of which are now largely amortized, are able to generate base-load electricity at a cheaper cost than plants burning coal or even gas. Under those circumstances, which could hardly be expected a few years ago, there is no surprise to notice at present clear signs which could be the harbinger of a renewal of deployment of nuclear energy in the US. For sure it is too early to announce that it will take place soon, but what can be asserted is that a prerequisite, namely economic competitivity of nuclear power in the US, is now a reality.

I made reference to a possible revival of nuclear energy in America because it is an up-to-date question of great interest, but also because its outcome is likely to be seen as a warning and a lesson by other countries as well.

However, the fact that nuclear power can be economically competitive has already been clearly demonstrated elsewhere. May I mention the case of my country, where it is fair to say that the development of a large nuclear power program was greatly facilitated by the lack of significant domestic resources in coal, oil and gas. A major element was the definition at government level and the implementation by EDF of a lasting energy strategy involving the erection of series of standardized nuclear units scheduled over many years.

Detailed studies carried out under the care of the French Industry and Energy ministry have repeatedly shown that the use of nuclear power was the cheapest way to produce base-load electricity in France.

Last year, at the request of the French government, an "Economic study of the nuclear power option" was carried out by MM. Charpin, Dessus and Pellat whose report was issued in August 2000. They examined a number of scenarios covering the period 2000-2050, differing mainly by the respective parts taken by nuclear energy and gas (through combined cycles and cogeneration) to produce electricity. They supposed that the electricity demand will either remain stable or double over the period. They made a wide range of assumptions, technical, economic and financial, some of them extremely prejudicial to nuclear energy. Yet the conclusion was crystal clear. Under the conditions prevailing in France nuclear energy is economically competitive with the use of gas, without even assuming a significant increase in the price of the latter in comparison with what it was in 1999 (2,8 $/million Btu). Scenarios with a high nuclear content are favoured. The most expensive ones are those assuming that the present nuclear power plants would not be renewed after they reach the end of their lifetime. I insist on the fact that the cost of nuclear power evaluated in this study takes into account environmental externalities (management of radioactive wastes), and includes R&D expenses, decommissioning, dismantling, decontamination, etc¼ .

I am fully supporting research and development on renewable energies. Yet most of them, with the notable and remarkable exception of hydropower, are still far from economic competitivity. Up to now, their use can only be justified from that standpoint in areas not well connected to electricity grids. Let me mention that in order to promote the development of wind power, the French government instructed EDF to purchase at 0,085 euros the KWh produced by wind power generators, though it is intermittent and irregular, while the guaranteed KWh produced by nuclear power plants costs three times less to the French utility.

A very important economic advantage of nuclear energy is to guarantee that the KWh cost remains stable over the years and to offer a reference level for long-term electricity prices.The purchase of natural uranium accounts for 5% or so of the cost of the KWh produced by a light water reactor. Even if the uranium price would double, which is very unlikely in the near future as large stocks exist on the world market, the KWh cost would increase by 5% only. On the contrary the cost of the KWh produced by burning fossil fuels is exposed to large variations, as it is strongly dependent on the market price of oil, gas or coal.

Another remark is meaningful, from an economical and also a social standpoint. A major part of the expenses required to produce electricity by means of nuclear power can be made domestically. To quote again the French case, this has a very positive effect on the foreign trade balance. Last year, had France to import fossil fuels to produce the same amount of electricity which was generated by its nuclear power plants, it should have paid an additional bill of 16 billion $. On the contrary France was able to export 70 TWh to other European countries.

There is still much room for further improvement in the economy of nuclear energy, which is a young technology. Significant reductions can be expected in the investment cost of nuclear power plants per KWe installed, and more generally in the cost of the KWh they produce.

This is one of the main objectives of the so-called Generation-IV project initiated last year by the US DOE jointly with a number of other countries. The aim is that future nuclear energy systems have a clear life-cycle cost advantage over other energy sources and a level of financial risks comparable to that of other energy projects. These prospects are likely to make financially attractive nuclear power projects based on series of units of smaller size, in spite of their larger capital cost per KWh, and thus to extend the opportunities favourable to the deployment of nuclear energy.

Over the first fifty years of industrial use of nuclear energy, there have been a few severe accidents on nuclear reactors, among which the one which occured at Chernobyl on April 1986 can be rightly called a catastrophe. 31 people died and many more received large exposures. It is particularly painful that about 2000 cases of thyroïd cancers were observed on young children in spots of Ukraïna and Bielorussia where local wheater conditions gave rise to large radioactive fallouts during the days following the explosion of the reactor.

Examining the causes and circumstances of this accident, a series of deficiencies appear, which bear witness to basic blemishes in the Soviet system. The safety culture was notably insufficient as far as civil applications of nuclear power are concerned. During the last years of his life, Andrei Sakharov had addressed solemn warnings to the Soviet authorities about the poor safety conditions under which their nuclear installations operated, but to no avail.

It is not my point to try to minimize what happened at Chernobyl, but comparisons may be appropriate. Without referring to natural disasters, like devastating earthquakes, whose death toll reached at times one million people, recurrent catastrophes happen unfortunately as a result of human activities for peaceful purposes. As one of many examples, think of the accident in a chemical factory which occured at Bhopal in India at about the same time as that of Chernobyl. It killed right away thousands of people. I would not say that it is now forgotten, but the groups which continue year after year to spread terror in the population about Chernobyl, not hesitating to falsify the data to support their claims, display at least a selective indignation.

In the energy sector, it is not infrequent that a big hydropower dam breaks down in the world, causing on occasion the death of hundredths of people, a cruel experience undergone by Italy and France among others.

However the death of a victim of an event linked to nuclear energy is felt by the public more deeply than that of anybody passing away for any other cause. I may venture to say that the former is more dead than the latter.

A typical example is the criticality accident which happened in September 1999 in Japan, where two workers of an uranium conversion plant died as a consequence of the large irradiation they received following a gross handling mistake. I am fully compassionate towards these men, who seem to have been kept ignorant of the elementary precautions they had to take. Nevertheless, having in mind all the people who are every day the innocent victims of fatalities whose causes are entirely foreign to them, one cannot refrain from being struck by the extreme emotional reactions raised by this very unfortunate accident, even taking into account that it took place in the country of Hiroshima and Nagasaki.

To be sure mankind first knew about nuclear energy through the gigantic destructions produced by the atomic bombs which put an end to the second world war. In addition to its utmost intrinsic power, the aura of mystery which still surrounds it keeps alive the fears of people, even when it is used for entirely peaceful purposes. Besides, radioactive substances emit insidious radiations, which are impervious to our senses and seem to pertain to some uncanny world. Somehow nuclear energy has become the focus of latent anxieties of the population of our modern societies. For some people, it seems to be the incarnation of evil.

At all events, it is obvious that its use has to be submitted to most stringent measures, but this is exactly what happens. On the one hand the operators, who are responsible for the safe conduct of their installation, must follow strict rules to comply with their duty. On the other hand, they are continuously under the control of safety authorities depending from the government, alone entitled to grant the operating licences and to rescind them at any time.

Over the last half-century, a considerable body of expertise has been acquired by running several hundreds nuclear power plants in more than thirty countries. The cumulative duration of their operation exceeds ten thousand years at present. Safety features and margins are now well understood, the principle of defence in depth is well incorporated in the designs, the rules to obey and the practices to follow in order to prevent abnormal events and to keep incidents from deteriorating into more severe accidents are well defined. This safety corpus is more and more codified and agreed upon worldwide.

Generally speaking, the reliability and safety performances of nuclear power plants in service to-day are very positive. May I mention the French experience, not because I consider it as particularly good, but because I know it best.

As it is well known, there is an international scale on which nuclear incidents and accidents are registered, and rated from level 1 (an anomaly) to level 7 (a major accident, typically that of Chernobyl). From 1990 till 2000, 96% of all events recorded on the 60 French nuclear power plants were at level 1. In addition 43 were registered at level 2 (a simple incident), which means on an average less than one per unit over eleven years, and none at any level higher than 2.

During the whole year 2000, 90% of the doses received by the personnel of EDF and its subcontractors working in nuclear power plants were below 10 mSv, and two people only got more than 20 mSv. Many investigations have been conducted to assess the potential effects of nuclear installations on the exposure of people living nearby. They have consistently shown that their impact is absolutely negligible, less than 1% of the mean level of natural radioactivity, which is about 2 mSv per year in France. No French nuclear installation was ever demonstrated to be the cause of an excess of cancers in the surrounding area, contrary to the claims of groups which launched campaigns purposely trying to prove it.

Like in any other industrial sector, the safety features of nuclear energy are continuously improving as a result of the operational experience acquired and specific R&D programs. This is one of the main objectives of the current "International project on innovative reactors and fuel cycle systems" conducted by the IAEA.

There has been over the years a strong trend to reduce further the possibility of reactor core damage. Passive features to provide cooling of the fuel and reducing the need for uninterrupted electrical power, have been valuable factors to this end. A major safety goal of the Generation IV project is to remove the potential for radioactive releases outside of the reactor containment from any severe accident and therefore to eliminate the need for offsite emergency response.

The ability of nuclear installations, whether reactors or fuel cycle plants are at stake, to resist external aggressions will for sure be reexamined in the wake of the dramatic events which took place one month ago in the U.S. It is likely that the debate of long standing about their construction underground will be renewed.

As a general rule, the containment of a nuclear power reactor is designed to withstand the direct hit of a small plane, but it is doubtful that most of them would resist to the crash of a large airliner at full speed. Such threats were considered so far as too unlikely to be taken into account in a systematic way. In any case the measures to be taken to prevent them were ascribable to the public authorities and lay beyond the responsibility of the operators themselves.

The strengthening of safety is indeed a continuous process, which was moving forward well before the recent terrorist assaults. Take for example the case of the EPR project designed jointly by Framatome and Siemens. This new PWR has advanced safety features designed for the prevention and mitigation of severe accidents. Its confinement enclosure comprises two successive walls which make it extremely robust. A spreading chamber is provided beneath the core to dispose of corium in the very hypothetical case of a core melt-down. Various auxiliaries needed for cooling the reactor core after shutdown are located within the containment itself instead of being housed in conventional buildings outside of it.

Our modern societies, which were yearning after an illusory zero-risk way of life, are bluntly compelled to face major threats which had remained more or less hidden for long, so that little attention was paid to them. Henceforth people can no more ignore them and will have to be prepared for them. In the field of nuclear energy, like in many others, additional and more stringent safety and security measures may have to be taken to counter and to minimize them. But there are obvious limits and one should not indulge in the fallacious hope that all kinds of dangers could be eradicated for ever. If one takes up extreme emergency situations due to terrorism within the framework of what is indeed a war logic, one can always imagine catastrophic scenarios which would nullify any protective measure, however staunch it is.

It will never be possible to rule out the possibility of occurence of even a severe nuclear accident, whatever the precautions taken. Nevertheless, under the conditions which prevailed till now, its consequences for the workers and the public would have remained extremely limited. We must make sure that this remains true in the new context to which we are confronted.

I am fully aware of the difficulty to mitigate the fears of the public with respect to nuclear energy and radioactivity in general by resorting to rational arguments, statistical data and probabilistic assessments. Besides, those fears are often stirred up by pressure groups inspired by ideological ends, motivated by political aims or simply driven by financial interests. Trading scare has always been a profitable business.

A long time is likely to be required before people recognize the benefits they draw from nuclear energy so that it becomes commonplace in public opinion. A prerequisite is that nuclear power plants continue to be operated worldwide with the same rigor as this is the case now. I also hope that older plants, whose safety characteristics do no more correspond to to-day standards, can be replaced soon.

Environment protection is becoming rightly a major concern. We are more and more aware that our unique planet is fragile. For the first time since billions of years, a living species disposes of means and carries on activities liable to affect the delicate balance on which the biosphere is operating, with consequences difficult to seize but eventually forbidding and escaping control.

Like for any other human activity, it is compulsory to make sure that the use of nuclear power is environmentally sound. The potential effects of a nuclear installation on the environment have to be examined in two bearings, namely the effluents it produces during operation and the wastes it leaves behind.

I will consider first this second topics, as the issue of the highly radioactive wastes produced by nuclear power plants is the one to which public opinion is at present most sensitive. At least on the short term it will have a major impact on the development of nuclear energy programs. One of the main obstacles to the resumption of orders for the construction of nuclear power plants in the US is the uncertainty about the Yucca Mountain repository to dispose of utility spent fuel.

Antinuclear groups claim that there is no solution to this problem, which is absolutely wrong. At the same time they try by all means, not excluding violent deeds, to oppose pursuing activities of research, development and demonstration to the effect of improving and validating the techniques worked out so far.

Since many years comprehensive programs to cope with radioactive wastes management have been carried out in various countries, with a care which can be seen as a model to follow in many other industrial sectors.

Fission products, which for the most part have little or no application at present, are the only ones to be considered as highly radioactive wastes. Obviously they must be managed with utmost precautions, owing to their extremely high initial level of radioactivity and their very long decay time. People have to realize that a very long decay time means a very small radioactivity. Poisonous chemical wastes, which do not decay, keep for ever their toxicity.

Though I fully appreciate the excellent work carried on by several countries which adopted the option of direct disposal of spent fuel, my personal opinion is that this is not the best choice for the future. I doubt that in the long run it would be considered reasonable to bury plutonium with the fission products.

As you may know, the solution chosen in France, like in several other countries, is in keeping with a basic principle of what I consider a sound policy of wastes management, which implies to separate the different components and to treat each of them in the most appropriate way.

While plutonium is a material of considerable energetic value to keep for further use, the fission products, embedded in a special glass matrix, are enclosed within containers incorporating a series of successive barriers, to be disposed of in deep geologic formations selected according to a set of criteria (stability, hydrology, etc¼ ).

I will not insist on the characteristics and performances of this technique, but a few remarks are appropriate.

The containers can be guaranteed to remain tight for several thousands of years. Thereafter most of the b and g radioactivity of the vitrified wastes will have disappeared, the containers will be cold and they could be handled with bare hands. Later on, the containers are prone to lose progressively their tightness, but the residual radioactivity liable to leak within the underground will be extremely small, much lower than that occuring in natural uranium deposits. In that respect, the experience provided by the Oklo natural reactor is particularly revealing and reassuring.

May I add that the amount of highly radioactive wastes resulting from the use of nuclear energy is extremely small. Suppose a European family whose electricity needs would be entirely secured by nuclear power plants. The whole of the vitrified wastes corresponding to its electricity consumption over twenty years would not exceed the volume of a cigarette box.

I want to declare that the radioactive wastes management technique to which I made reference fully meets the requirement of not endangering the safety and health of human beeings. I am as much as anybody else conscious of the responsibility we all share in our daily activities with respect to our offspring, but we must keep reason and not pile up artificial requirements so as to make them impossible to meet. There are bounds which common sense demands not to overstep.

With regard to the second topics I mentioned above, namely the impact of nuclear installations on the environment in the course of their routine operation, I will be very brief.

Generally speaking, the volume of the effluents they release is much restricted, whether power stations or fuel cycle plants are concerned. Their radioactivity, which is permanently monitored, remains extremely small, well below the stringent limits fixed by the authorities. When antinuclear groups claim to have detected high levels of radioactivity at the outlet of the discharge pipe of the La Hague reprocessing plant, it is as if people would assess the concentration of carbon dioxyde in the atmosphere by putting their measuring device in the exhaust pipe of a car.

In comparison with other energy systems, nuclear energy is indeed extremely clean. Think to acid rains, large oil spills, etc¼ .

I do not intend to dwell on the subject of green-house gas emission, because I am not at all an expert on this matter and thus I prefer to refrain from expressing definitive views on their possible long-range effect on the earth climate. Yet I see that a general concern is growing about this problem and that many governments seem now ready to take measures in order to curb what could be a real threat. I know that studies are under way to evaluate the possibility to sequester C02 deep underground, but I notice that nobody seems to question the long term efficiency of those possible wells and to express moral torments about the responsibility we would assume from that standpoint to our distant offspring.

Whatever the case may be, it must be stressed that the use of nuclear energy does not produce any emission of green-house gases. To take the case of my country, where 80% of the electricity is generated by nuclear power plants, the average quantity of C02 released per KWh produced is ten times less than in some other European countries which have recourse for the most part to conventional plants burning fossil fuels. Would France not use at all nuclear energy, its total C02 emissions would be the double of what they are actually.

The know-how needed to design nuclear fission explosives is largely available. The main problem for countries which would embark upon manufacturing even a few of them would be to procure the required quantities of highly enriched uranium or plutonium. One way would be to divert them from installations devoted in principle to peaceful energy production Thus the very serious question arises whether a widespread use of nuclear power could possibly lead to the proliferation of nuclear weapons.

There are two complementary ways to tackle this problem.

First there are technical means. The proliferation resistance varies according to the features of the nuclear power system considered. It is sure that this will be an important criterion in their selection in the future. For example, it is to be expected that on line refueling of reactors will no more be considered as an acceptable option.

Special care has to be taken at specific places of the nuclear fuel cycle, the most sensitive being enrichment and reprocessing plants. Though 3% enriched uranium is unfit for the manufacture of any nuclear explosive, a significant part of the separative work required to produce highly enriched uranium has already been accomplished. On the other hand, spent fuel is a plutonium mine, but as long as the latter remains mixed with the fission products, it is extremely difficult to handle.

Plutonium produced in light-water reactors contains a significant proportion of isotopes like 240Pu and 242Pu which are undesirable for military purposes. It is not strictly impossible to fabricate a fission explosive with reactor-grade plutonium, but such an accomplishment, while being within reach of a country having already acquired elaborate mastery of the design of nuclear weapons, is difficult to carry through and of doughtful efficiency. The United States have declared that they had manufactured an explosive device with plutonium from a commercial reactor, but without giving information on the characteristics of this plutonium. One may think that it originated in a low burn-up fuel.

Anyhow, the best way to improve the proliferation resistance of plutonium is to increase the burn-up of the nuclear fuel from which it has to be extracted. Such a trend is also dictated by economic considerations.

Whatever efficient intrinsic technical barriers might be, they cannot be sufficient by themselves. The ultimate protection against proliferation is to be found in control means agreed upon within an international framework. Those institutional dispositions are indispensable, if only because, whereas there is no physical impossibility to divert fissile materials from peaceful activities to explosive uses, they can also and even better be produced in dedicated facilities, without any link with nuclear power plants.

For instance, as shown by the Iraki venture, highly enriched uranium could best be made in small installations equipped with ultracentrifuges, though this technique requires to master the use of UF6, which is not easy to handle. In a similar vein, one could produce plutonium by irradiating depleted uranium with a neutron source provided through spallation reactions by a high energy-high current accelerator, though this is a sophisticated equipment, and chemical reprocessing has to be used. Early 1950 the US AEC had approved a proposal from Ernest Lawrence to construct for that purpose the so-called Mark I linear accelerator, delivering a 50 mA current of 25 MeV protons, which was the first facility built at the Livermore site.

Various international agreements have been concluded, either on the world scale, or within a regional or bilateral frame, in pursuance of which the signatories commit themselves neither to manufacture nor to possess nuclear weapons.

The possibility that terrorist groups could do it in a clandestine way was thoroughly discussed in the past. It was generally concluded that such a venture was beyond the scope of any such group without the active support and complicity of an established government. Besides it was felt that, unfortunately, terrorist groups could resort to easier and more conventional ways, making use for example of toxic chemical or biological weapons, to perpetrate extreme criminal acts of mass destruction. After the recent awful events in the United States, it is clear that the international community will bring major care upon dealing anew with this matter, which can be addressed more precisely when the organization of the terrorist networks existing in the world is better understood.

The chief existing instrument to deal with the problem at the level of governments is the Non Proliferation Treaty, enforced in 1970. It has been signed to day by almost 200 countries, the most notable exceptions being India, Pakistan, which have already exploded nuclear devices, and Israel, which is widely supposed to possess a number of them. The implementation of the NPT is committed to the care of the International Atomic Energy Agency, which was instituted in 1957 within the frame of the United Nations.

Safeguard agreements have to be concluded between IAEA and any particular country. Initially IAEA had to rely on the evidence supplied by the country itself and was obliged to limit its controls and inspections to the peaceful nuclear activities the latter declared.

In two cases countries were found violating the engagements they had made in signing the TNP. In 1991 it was discovered that Irak was developing a clandestine program to produce highly enriched uranium for military purposes. A little later, anomalies observed in the declared quantities of spent fuel produced by a North Korean research reactor and refusal by the authorities of this country to let IAEA inspectors have access to the laboratory where it could have been reprocessed gave a clear evidence that North Korea was attempting to produce military plutonium.

As a follow-up of those events, a large consensus was reached at the IAEA to greatly strengthen its proceedings and ways of intervention. This was done in several steps, until a model of additional protocol to the existing safeguard agreements was worked out in 1997. In signing this protocol, the concerned country commits itself to supply to the IAEA many more information, covering the whole of its nuclear programs, while IAEA inspectors become entitled to visit at any time, and without prior notice, any part of a nuclear site they want, to collect samples and to extend their investigations beyond the declared activities. In addition apparatus like cameras directly connected to the IAEA offices or automatic registers are installed at particularly sensitive locations to watch permanently what is going on. IAEA binds itself to help any country installing elaborate devices to ensure the physical protection of nuclear materials.

However many countries have not yet signed those additional protocols or not even subscribed to basic safeguards. This situation is unsatisfactory.

In 1995 the signatories of the NPT agreed to extend its validity indefinitely and to condition nuclear exports on full-scope IAEA safeguards. At the same time, as a counterpart requested by non-nuclear states, there was a general agreement to make further progress towards a worldwide nuclear disarmament.

Following the Start-I treaty between the US and Russia, the number of nuclear warheads at the disposition of both countries has already been greatly reduced, but the Start-II one, intended to go further, has not yet been ratified by the American Senate. For the same reason, the international treaty instituted in 1996 to completely ban further tests of nuclear devices has not yet been formally enforced. The discussion of the terms of another treaty, to prohibit the production of fissile materials for military purposes, makes little headway at the Disarmament Conference of the United Nations in Geneva.

In spite of the significant forward steps already taken, many people are disappointed by the slow pace of progress along the road towards a world free of nuclear weapons. Such a prospect implies a peaceful world lastingly relieved and devoid of major tensions, conflicts and internal struggles, and it is all too clear that we are still very far from it.

I do not intend to discuss in-depth this major problem here, and I will come back to the basic subject of my paper, namely the risk that peaceful nuclear power programs could contribute to the proliferation of nuclear explosives.

The experience of the IAEA over several decades is extremely positive. It did not bring to light any illicit diversion for any kind of military application of materials from nuclear fuel cycles used for energy production. Its safeguard system has proven to be extremely efficient to prevent possible misuses, to sound the alert and to anticipate the measures to be taken in case of any such attempt.

The means at the disposal of IAEA and governments to prevent and curb such diversions have been considerably reinforced, the reliability and performance of the methods and techniques in current use for that purpose are regularly improving. Elaborate physical protection measures, especially during transport of fissile materials, plays a major role to hinder terrorist groups from seizing fissile products, radioactive materials or nuclear equipment of military significance. AIEA gives now highest priority to develop a more effective national and international system in order to strenghten physical security over nuclear materials and to combat illicit trafficking.

On several occasions illicit trafficking of radioactive materials has been reported on the international scene. In many cases, it happened to be a matter of blackmail based on nonfissile chemical products dressed up in fantasy names or, in some instances, on small quantities of natural or depleted uranium. After the collapse of the Soviet Union it was feared that significant amounts of fissile materials of military significance could be smuggled, but to my knowledge this did not happen. Nevertheless extreme vigilance is more than ever mandatory.

In that respect like in many others fields, we must be on constant alert. Nothing can be settled for ever. Yet my personal opinion is that mankind disposes of the tools to protect itself, and I am confident that nuclear energy can be deployed on a large scale in the world without contributing to the proliferation of nuclear weapons. On the other hand it is highly satisfactory to see that the US and Russia have agreed to transfer to civil uses large quantities of highly enriched uranium and plutonium from their military arsenals. Such transfers are under way and IAEA will take a part in checking them.

When an overall balance is struck between the pros and cons of nuclear energy with respect to the various criteria reviewed above, my personal opinion is that the result is positive and favours its future development.

This does not mean that nuclear energy has no drawback, but everything is relative. To put a sound judgment, we must compare it with other energy sources and evaluate situations where it would be left aside.

Its implementation requires obviously many precautions. It is certain that the recent terrorist assaults in the US will lead to a detailed reinvestigation of the conditions of its use, if only from the safety and non-proliferation standpoints.

But the impact of these dreadful acts on the energy programs of the world is by far not limited to pose the question of reinforced measures of protection. They raise many other important interrogations.

They underline again the problems linked to the supply of oil and gas on the international scene. A significant part comes from regions of the globe which are particularly exposed to the influence of terrorist movements. A new warning is sound that our fossil fuel supplies are affected by uncertainties. In particular the prices at which we can have access to them are liable to vary in large proportions, as had happened before.

All democratic governments have expressed their will to fight against terrorism, under all its guises. When we look at the way nuclear energy was and continues to be attacked in most countries, through campaigns well coordinated over their boundaries by people obeying sectarian tenets and refusing to accept decisions made in a fully democratic way, I ask you: Are we far from real attempts of subversion? When, for example, armed commandos of demonstrators, well trained to guerilla actions, try to oppose by violence the transports of spent nuclear fuel decided in accordance with established law, I ask you: Is this not terrorism? I hope that our governments will ponder and answer such questions.

Future is truly unpredictable, and no one can foresee how our world will behave, even during this century. But we have the choice of two things. Either we will prove able to solve the basic problems which jeopardize the well-being of a large part of the inhabitants of earth, and to settle by peaceful means the conflicts full of hatred which oppose them in many places. In such a case, the deployment of nuclear energy can proceed smoothly. Or, unfortunately, we will fail, with dramatic consequences impossible to foresee. Everything may happen, including major international wars, where all kinds of weapons could be used.

We must hope that reason will prevail to prevent what could be an unprecedented world disaster. One thing is sure for me. I do not see how our small planet could enjoy lasting harmony and peace as long as so shocking differences exist between the peoples who live in it, as far as food supply, medical care, education, etc¼ are concerned. A huge and urgent effort from the rich and developd nations is mandatory to help raising the standard of living of the poor countries.

Abundant energy supplies are a key element to cure the world of its sufferings. All kinds of energy resources must be tapped, the selection being made in each case according to the local requirements.

I cannot imagine that mankind would forbear from taking the advantage of nuclear energy, a resource which is immediately available, cheap, clean and safe, which has a large potential of innovation, and which can contribute to fulfil its needs for a very long period of sustainable development.

Its deployment worldwide can only be progressive, as many countries do not yet dispose of the financial means, of the industrial infrastructures, and above all, of enough well-trained personnel having the expertise required to operate installations which are and will remain high-tech products. In the mean time, as the total energy resource is not unlimited, the countries which are already industrialized should, in a spirit of solidarity, emphasize the use of nuclear energy for themselves.

May I hope that on December 2, 2042, the hundredth anniversary of the first man-made chain reaction will be celebrated with all the cheers it deserves as one of the main and most beneficial events in human history.