13 December 1996 | University of Santo Tomas, Manila

The Good uses of Nuclear Energy

252nd Memorial Lecture at the Faculty of Medicine & Surgery

by Director General Hans Blix

A famous faculty of medicine does not need to be told that there are good uses of nuclear energy. It is fully aware that radioactivity was discovered a hundred years ago and has been used for human benefit, not least in the medical field, for half a century. It knows that modern medicine would be unthinkable without diagnostic radiology and radiotherapy. Indeed, these techniques have become so common, so reliable and so accurate that, in the Western industrialized world, about one patient in every three undergoes some form of radiological procedure - diagnostic or therapeutic. In this lecture I propose nevertheless to describe how the International Atomic Energy Agency seeks to promote the development and dissemination of nuclear techniques which are beneficial to us, including nuclear medicine.

Before I do so, however, I must acknowledge what is implicit in the title of this lecture on the good uses of nuclear energy, namely that there are also uses which are not good. Indeed, I fear most people associate the word "nuclear" primarily with weapons, and perhaps secondly with nuclear power accidents and these associations often spill over on their attitudes to the nuclear uses that are beneficial. Although regrettable, this is perhaps after all not so surprising. It is more than 50 years since the first - and only - atomic bombs were used at Hiroshima and Nagasaki. Who can forget the devastating effects they had, and the immense suffering that they caused? Then, just ten years ago, there was Chernobyl when a nuclear power reactor of very special design surged out of control during an ill-conceived experiment and hurled radioactivity into the sky. That major disaster still affects the populations in the region and still has a major impact on people's attitude to nuclear power. These two dramatic cases certainly remind us of the destructive potential of the atom turned loose. We should perhaps remember, however, that nuclear energy is by no means unique in having a potential for giving both good and bad.

Take fire. Fire is fundamental to human civilization. It permitted our ancestors to shape tools that enabled them to till the soil and harvest crops. But it also enabled them to wage war on neighbours. And we know that throughout history fire let loose has brought immeasurable destruction to villages, cities and forests. Fire, like nuclear energy, can be used for good and bad.

Another example: gunpowder. Its invention has helped to perfect weapons for hunting and to blast mineral ores. Yet, how many millions of human beings have been killed or injured in war, insurgency and in random violence?

One last example: the aeroplane. The same technology that has made the world smaller and brought us closer is the one that introduced terrible new dimensions to warfare, including the bombardment of cities far behind the lines of battles.

The United States, as the first country to make a nuclear bomb, and also the first in which a controlled nuclear chain reaction took place, was quick to recognize nuclear's potential for good and evil. It decided to provide a disincentive for the military use by offering to share with other States much of its knowledge of the peaceful use of nuclear energy - in return for pledges of exclusively peaceful use from the recipients of such know-how. This bargain was articulated in President Eisenhower's "Atoms for Peace" speech at the United Nations in the early 1950s and the International Atomic Energy Agency (or IAEA) traces its origin to this policy.

A conference in Geneva in the 1950s revealed vast amounts of thitherto secret scientific data and raised tremendous hopes for a new nuclear era. Forty years on we can see that some of the hopes have come true - both regarding actual peaceful use and regarding pledges against the military use. Today some 17% of the world's electricity is nuclear-generated, to point to the most spectacular result. And, under the Nuclear Non-Proliferation Treaty (NPT), some 180 non-nuclear-weapon States have now committed themselves for an indefinite period of time not to acquire nuclear weapons. Moreover, a Comprehensive Test Ban has recently been adopted. There are also disappointments, however. Despite the beginning of nuclear disarmament, the five declared nuclear-weapon States still have thousands of nuclear warheads and neither the risk of proliferation nor the risk of trafficking in nuclear materials have been eliminated.

The IAEA itself was set up in 1957 precisely to promote the good applications of nuclear energy and to help States verify, at their request - through international inspections - that their uses of nuclear energy were indeed peaceful. You will find our inspectors going about their work daily from South Africa to the Democratic People's Republic of Korea, from Iraq to Argentina and Brazil. In performing our statutory tasks, we have accumulated a rich experience in serving the international community in two major respects - as an institution generating norms and providing services and assistance for the use of peaceful nuclear technology and acting as what might be termed external auditors to keep track of stocks of nuclear materials to give confidence that they are not diverted for weapons purposes.

The Field of Medicine

Let me now revert to the field closest to your professional calling, namely medicine. A major part of the IAEA's technical co-operation programme is devoted to the promotion of human health. Examples are projects through which the Agency is helping to foster the use of cancer diagnosis and therapy by nuclear means in developing nations such as Ghana, Tanzania, Mongolia and Nicaragua. I might also mention brachytherapy, which the IAEA is helping to apply in all our developing Member States in Asia.

Nuclear techniques - and particularly medical ones - must be used under proper rules and rigorous control. The IAEA is one of six international organizations that co-operated in developing some rules of fundamental importance, the so-called Basic Safety Standards for Protection against Ionizing Radiation and for the Safety of Radiation Sources - the BSS for short. The IAEA also co-operates with the World Health Organization (WHO) in establishing conformity of radiation measurements in radiotherapy units worldwide through a network of secondary dosimetry laboratories (SSDLs). In industrialized countries, hospitals achieve conformity through calibration of their dosimeters to national primary standards. But the heavy workload of the world's 13 Primary Standard Dosimetry Laboratories does not allow the calibration of reference dosimeters from thousands of other hospitals throughout the world. Competent national authorities have therefore designated SSDLs, in a programme started in 1976, to provide certified calibrations.

The Agency also seeks to provide a forum for discussion of effects of low-level radiation, which is an area of much scientific controversy and some public anxiety. The health hazards of exposure to high levels of radiation are well known and documented: exposed persons show acute clinical effects and the severity is directly linked to the radiation dose. In general, however, the doses at which statistical links can be demonstrated to illness and death in human populations are many times higher than the doses from which governments seek to protect their populations. An important question is whether very small increases of radiation doses above the natural background levels in reality result in any increased risk. The International Commission on Radiation Protection recommends the use of a linear, no-threshold model to extrapolate the risks of low dose exposure from higher dose observations. Some argue that this leads to exaggerated, unduly expensive protection measures. Regardless of these differences all experts agree that the risks from low-level radiation are very small. The need is for policies that are both prudent and practical. The linear, no-threshold hypothesis has merit as a basis for precautionary action, but very small risks should not be allowed to lead to absurdly expensive protective measures. The use of the hypothesis as a basis for regulation and decisions needs to be approached with care and the same is true for public information about it.

Food and Agriculture

I turn now to comment on the good use of nuclear techniques in the field of agriculture - a key area for the developing world.

To give some examples, radioisotopes and radiation are applied in this field,

- to create induced mutations in plants to obtain desired agricultural crop varieties;

- to determine conditions necessary for optimizing fertilizer and water use, as well as biological nitrogen fixation;

- to eradicate or control insect pests;

- to improve reproductive performance, nutritional status and yield of animals;

- to reduce post-harvest losses by suppressing sprouting and contamination and extending shelf life of foodstuffs; and

- to study the pathway of pesticides and agrochemicals in the environment and food chain.

Let me explain further and give you some concrete examples.


Isotopic techniques provide important analytical tools in the management and husbanding of existing supplies of water and in the identification of new, replenishable and exploitable sources of water. The IAEA has a dedicated isotope hydrology laboratory that supports development activities in Member States. We assist countries with chronic water shortages such as Morocco, Senegal and Ethiopia. Over the last ten years the IAEA has supported almost 160 projects worth 20 million dollars to help Member States develop national infrastructure in isotope hydrology applications. Some 550 scientists have been trained in the relevant skills.

Measurement of nitrogen uptake in crops

In co-operation with the FAO, the IAEA has perfected the N15 technique method to measure how nitrogen is taken up by plants from the atmosphere, from the soil and applied fertilizers. The technique provides an estimate of the total nitrogen fixed during the entire growing season. By this means, more efficient nitrogen fixing legumes with higher yield and protein content can be identified and selected. The FAO and IAEA jointly support some 30 projects worldwide on the production and use of biofertilizers for increasing biological nitrogen fixation and yield of grain legumes. Where biofertilizers are applied, production has been raised by 25 percent in countries like Bangladesh, China, India, Malaysia, Pakistan, the Philippines, Sri Lanka, Thailand and Vietnam.

Tsetse Fly

You are familiar with the sleeping sickness, transmitted by the tsetse fly. The presence of this insect has prevented settlement and development of large areas of Africa. While some species of tsetse have been temporarily controlled in West Africa, eradication has proved an elusive goal. Along with the FAO, the IAEA has recently successfully been targeting one species of tsetse that has caused sizeable losses of cattle on the island of Zanzibar (Tanzania) and we are confident that eradication will result.

The technique used involves a unique, non-polluting method which has already been applied successfully to numerous other insect pests in recent years. Tsetse flies are reared in vast numbers and radiation-sterilized male flies are released in large numbers by air over an infested area. When they mate with wild females, no offspring are produced and infestation can thus be reduced and ultimately eliminated. This is particularly true in a confined area such as the island of Zanzibar, where the risk of re-infestation from the outside is minimal and where we hope to achieve success by the end of 1997. It would also be true of the Southern Rift Valley in Ethiopia where we expect to apply the technique in the near future.

Food Irradiation

The use of irradiation technology to preserve food is gaining more attention around the world. In 37 countries, health and safety authorities have approved irradiation of over 40 kinds of food, ranging from spices to grains, to deboned chicken, fruit and vegetables. Today, consumers can safely enjoy irradiated strawberries in France, or local irradiated sausage in Thailand, for instance.

Here, too, rules and standards are needed for a responsible use of the technique. A worldwide standard for irradiated food was adopted already in 1983 by the Codex Alimentarius Commission, which is a joint body of the FAO and the WHO representing over 130 countries. An expert committee has reported to the Commission that the irradiation of any food commodity up to an overall average dose of 10 kilogray presented no toxicological hazard, required no further testing, and introduced no special nutritional or microbiological problems.

Governmental interest in the process stems from a variety of reasons: there are high losses of food (typically 25% of all food production) due to infestation, contamination and spoilage after harvesting; concern about foodborne diseases; and growing international trade in foodstuffs that must meet stringent import standards of quality and quarantine.

While the Codex Alimentarius Commission exercises oversight regarding the foodstuffs, international radiation protection regulations lay down rules for the safe operation of plants where irradiation takes place. The IAEA helps in formulating such rules. The Agency has likewise often provided assistance to countries wishing to test or use this novel technology. I should add that food irradiation still encounters resistance from various groups. Considering that astronauts and especially sensitive patients are often given irradiated food to reduce the risk of stomach infections, one may wonder why healthy people in normal conditions would object.


Industrial applications of nuclear techniques are numerous. Let me mention some.


In today's high-tech telecommunications world, there is a great demand for lightweight, durable and versatile polymer covers, for example for cables. Exposure of polymers to low levels of radiation delivers precisely that kind of product to the electronics industry. It is a growing business and the IAEA has been active to help transfer this technology to South East Asia, under a long-standing and very successful regional co-operation agreement for Asia and the Pacific (RCA).


Another important application of nuclear techniques is the fine measurement of industrial products, such as paper thickness. The tightness of welds on gas or oil pipelines can also be verified by the application of gamma radiography, a nuclear technique that is not so different from X-rays.

Geothermal power

As you will know, the five million inhabitants of the island of Negros in the Philippines obtain all their electricity from geothermal plants. At the IAEA isotope hydrology laboratory in Vienna, we investigate geothermal systems by isotopic techniques to optimize the use of such geothermal resources. In some countries, like Costa Rica and Nicaragua, the Agency has also provided isotope techniques to help map the geothermal resources to decide on the best location of installations.

Flue gas emissions

Another power-related development I want to tell you about is the use of accelerator generated electron beams in the chimney stacks of conventional coal-burning power plants. By this ingenious and original technique you can virtually eliminate sulphur and nitrogen emissions to the environment. Indeed, by adding ammonium, you transform these potentially polluting flue gases into fertilizers - ammonium sulphate and ammonium nitrate! This method is currently being demonstrated in a project which the IAEA is supporting near Warsaw in Poland. The method will not fulfil the alchemist's dream of transforming lead into gold, but transforming pollution into fertilizer is already not bad.


Ever since the major UN Conference on Environment and Development in Rio four years ago, hardly a week has gone by without a new report being issued somewhere in the world about the "greenhouse effect". It seems increasingly certain that the rapidly growing concentration of carbon dioxide and methane and other greenhouse gases in our atmosphere will lead to a rise in the temperature of the earth's atmosphere - global warming. There is much talk about the stabilization or reduction of the emissions of "greenhouse gases". However, the rhetoric and the reality go in opposite directions: carbon dioxide emissions actually continue to rise everywhere. In a speech here in Manila the other day I tried to show that a greater reliance on nuclear power in the world could help restrain the burning of CO2 emitting fossil-fuelled plants. I shall not repeat what I said, but I might add in this research-oriented forum that techniques using radioisotopes are proving to be valuable tools in improving the understanding of the complex carbon cycle in the atmosphere and the oceans.

Nuclear Power

I shall also not repeat in this lecture what I said about the pros and cons of nuclear power and the likelihood of and need for a more general revival of the nuclear option, which has suffered stagnation in much of the Western industrialized world during the last 15 years but which is espoused in some of the rapidly developing countries in Asia. I would like to point out before this audience, however, that nuclear power may have several other uses than electricity generation. It may be used to produce industrial heat or steam for district heating in countries where this is demanded, and even for propulsion systems for merchant shipping. The nuclear-propelled aircraft carriers and submarines of the Great Powers have demonstrated the viability of the technology, and the Russian ice-breakers have shown that nuclear-powered ships can work year after year in the most difficult climatic conditions in the world - in the Arctic.

Moreover, countries short of drinking water - and such countries are regrettably becoming more numerous - are looking at the heat generated by nuclear reactors to desalinate sea water and make it potable. For some time the IAEA has been actively engaged in helping to explore that option, for instance in countries bordering on the Mediterranean.

And further - although there are a number of nuclear reactors in the world that have already been successfully operating for 40 years, nuclear power is still a relatively young technology. A second generation of fission reactors is just arriving - for example, the Advanced Boiling Water Reactor which went recently into operation in Japan. Given sufficient interest by governments and utilities, I see the potential for the third generation fission reactors, which are on the drawing-board today and which are expected to be simpler, cheaper and safer still.

One special type of reactor has had a good deal of adverse publicity - the fast breeder. Its special characteristic is to produce - breed - more plutonium fuel in the process of burning the original fuel. In fact, the breeder uses the energy contents of uranium some 40 times more effectively than an ordinary light water reactor. I do not suggest that the breeder is the answer to today's energy problems, because it is expensive and there is no shortage of uranium. However, the existence of the breeder as an already available technology gives us assurance that nuclear power can offer an almost inexhaustible supply of energy. It could be an important part of the answer to the world's fuel problems 30 years from now, when oil and gas and also uranium may be scarcer and more expensive, and renewable energies have not proved capable of generating the large volumes of energy needed.

One frequently voiced objection to nuclear power is the highly radioactive waste it produces. While there exist today satisfactory methods for safely disposing of this waste, I want to mention in this science-oriented forum that the day may come when these wastes can be managed through new advanced processes known as actinide partitioning and transmutation. Research into this is moving ahead in several countries along several parallel tracks. One involves use of an advanced liquid-metal reactor as part of an integrated fast reactor and fuel cycle system; another is an accelerator-driven, sub-critical fast reactor system. However, these new approaches still have a long way to go.


One exciting prospect, which is still worked on in the laboratories by the scientists, is the harnessing of nuclear fusion - essentially replicating the energy of the sun. This is a formidable and expensive scientific and technological challenge. Yet the magnitude of the progress achieved so far has encouraged several major countries around the world to support further work on a fusion reactor, including work that is being conducted under the aegis of the IAEA.

The role of fusion in nature can hardly be exaggerated: it is fusion that has powered the stars for billions of years. Fusion is therefore not only the source of solar energy but also of all fossil and most renewable forms of energy available on our planet. Here on earth, however, it is far more difficult to artificially create the conditions required for a self-sustaining, net power producing reaction in the case of fusion than in the case of fission.

Let me conclude: Having unlocked many of the secrets of the atom and benefiting from it, it is also our obligation to lock up the evil uses and to make sure, in addition, that our peaceful use of nuclear energy is safe and environmentally acceptable. Nuclear science and technology are giving the world a vast number of gifts, beneficial to health and wellbeing, including electric power. We should make good use of these gifts.

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