Table of Contents
The Energy Challenge
Nuclear Power Facts
Nuclear Power Advantages
The Salient Points
Annex I: The DECADES Project
Annex II: Nuclear Power Case Studies
Radiation and Toxic Pollutant Effects
The fear of radiation health effects, particularly from severe accidents and radioactive waste, is central to public concerns about nuclear power activities. A better public understanding of radiation and of the radiation exposure continually encountered in everyday life is fundamental to a balanced view of the health impacts of nuclear power.
Radiation is a fact of everyday life. Radioactive elements have been an integral part of the human environment since the universe was created 15 billion years ago. Radiation is a natural component of the air we breathe, of the earth we walk on, of the homes we live in, of the food we eat and of human tissues and bones. We are continuously exposed to cosmic radiation, particularly at higher elevations and during air travel.
On a global average, it is natural background radon gas released from the earth that accounts for almost 49% of the radiation exposure which an individual receives annually [Fig.: Annual Individual Radiation Exposure (2.7 mSv Total)]. Additional natural background exposure from cosmic radiation and radioactive materials in the earth and internal to our body accounts for somewhat more than 40%. The remaining 11% is human-made exposures almost totally due to medical diagnostic X rays and therapeutic radiation. Radioactive material from past nuclear test explosions amounts to a small 0.2% and all routine nuclear power related activities a minimal 0.006%.
Natural background radiation is location dependent. Many of the millions of Europeans living in the high radon gas locations in Austria, Finland, France, Spain, Sweden and the United Kingdom [Fig.: National Background Radiation Exposure - Western Europe] receive 10–20 times the global average natural background exposure received by residents of New York City, where radon gas levels are significantly lower. Even these high radiation exposures are further exceeded in some localized areas, as in parts of Brazil and India, where the individual exposure is more than one hundred times the global average and more than one million times the exposure from nuclear power related activities.
The radioactive atmospheric and ground contamination from the 1986 Chernobyl accident led to widely varying increases in individual exposures. But even for this situation, a comparison with normal daily background exposure provides some perspective. As the Chernobyl accident affected areas are in relatively low radon gas environments, the current daily individual radiation exposure - even of those living in the areas of highest contamination - is below the daily exposure levels of the many hundreds of thousands of people living in the high radon gas locations of Europe.
In fact, for the overwhelming majority of those who at the time of the accident lived in the highest contaminated areas and who will continue to live there, the accumulated total lifetime radiation exposure will be less than the accumulated total lifetime exposure of those Europeans living in high radon gas locations [Fig.: Average Lifetime Radiation Exposure]. Although still small, during a lifetime the possibility of radiation induced health effects would on average be greater for the high radon exposed inhabitants of Europe than for the Chernobyl exposed populations.
Radiation health effects
The biological effects of radiation are dependent on the amount of exposure. Very high exposures can damage and kill a sufficient number of cells to destroy organs and cause a breakdown in vital body functions, leading to severe disability or death within a short time. Their effects are well documented. On the other hand, very low level radiation related health effects cannot be identified since they would occur principally as cancers late in life, leading to premature deaths by several years. They would be an undetectable fraction of the anticipated 20% of populations that die of cancer due to other causes - the 20% value itself varying by several percentage points for differing populations as a result of specific environmental, dietary and genetic influences.
To study long term health effects, the Radiation Effects Research Foundation (RERF) in Hiroshima has carried out over the past five decades an extensive investigation of the Japanese survivors of the 1945 atomic bomb explosions at Hiroshima and Nagasaki. Some 87 000 people who received relatively high radiation exposures have been continuously monitored. Contrary to initial expectations of high numbers of radiation induced cancer deaths, the study projects some 600 deaths, in addition to some 16 000 anticipated cancer deaths due to other causes for this Japanese population - a 0.7% increase in the anticipated cancer death rate. The expected several-year loss in the average life expectancy will not materialize as above average health care for the survivors through early diagnosis and treatment of medical disorders, including cancer, is leading to increased longevity.
The RERF study has been used to extrapolate effects for very small exposures close to zero above the natural background radiation exposure. As exposure decreases, the likelihood of radiation induced cancer death is assumed to decrease linearly, reaching zero only at zero exposure above the background. Some scientists are critical of this type of extrapolation, assuming that a natural threshold exists for radiation effects, with very small incremental doses above a significantly larger natural background exposure posing no risk at all.
Radiation from nuclear activities
There has been no credible documentation of health effects associated with routine operation of commercial nuclear facilities anywhere in the world. Widely accepted investigations, such as the comprehensive 1990 National Institutes of Health (NIH) study of some one million cancer deaths in people living near nuclear power plants in the USA, demonstrate no correlation between cancer deaths and plant operations. Investigations carried out in Canada, France, Japan and the United Kingdom support the NIH results. A number of widely publicized studies reporting a linkage of radiation from nuclear power activities to occupational or public health consequences, such as the Sellafield occupational exposure study published in 1990 have been shown to be incorrect.
Comprehensive studies carried out by the European Union of various cancer types show the wide variability in cancer rates throughout Europe, which are probably due to environmental, dietary and genetic influences. High male leukaemia incidence is found in non-nuclear power countries such as Denmark, Ireland and Italy as well as in nuclear power countries such as France and Germany [Fig.: Male Leukaemia Incidence].
In considering health effects from nuclear power activities, any postulated risks from low level radiation exposures must be put into perspective with the known risks from the toxic pollutants released from other terms of energy production. Unfortunately the task of comparison is difficult, as there is vastly more scientific information about health effects from radiation than from the various toxic pollutants.
Toxic pollutant health effects
Fossil fuel combustion produces, in addition to CO2, noxious gases and a wide range of toxic pollutants that are the largest source of atmospheric pollution. In general, the level of pollution depends on the quantity of non-combustible material contained in the fuel, natural gas having the lowest level followed by oil and coal. The pollution potential is also dependent on the combustion technology and pollution controls used.
The combustion of coal always produces gaseous nitrous oxides. Sulphur impurities are emitted as gaseous sulphur dioxide. Inorganic impurities are released as a wide range of metals including radioactive elements; the volatile heavy metals such as mercury are emitted as vapour, while others such as cadmium and lead remain mostly in the ash residue. The incomplete burning of coal that always occurs adds black smoke - finely divided carbon and hydrocarbon particles known as particulate matter - along with carbon monoxide and a wide range of organic compounds.
Health effects from energy related pollutants, as with radiation, are exposure dependent. For high levels of toxic pollutant exposure there is no doubt about the potential health effects (Box 4). Acute respiratory disorders are well documented for high levels of atmospheric pollution, as are a number of respiratory disorders at more moderate levels. Heavy metal ingestion can cause a wide range of substance specific health disorders. Arsenic-containing coal used in the Czech Republic for many years caused high levels of contamination, and arsenic specific health effects have been documented in children living in affected areas.
As with radiation, there are formidable difficulties in demonstrating a connection between continuous exposures to low levels of pollutants in air, food or water and long term health effects that occur years later as additional illnesses including cancer. The higher overall death rates observed in areas with persistent atmospheric pollution, particularly from cardiovascular and pulmonary disorders, is a strong indicator that long term health effects from continuous low level exposures do develop. The WHO, in its 1997 report on sustainable development, estimates that deaths due to indoor and outdoor air pollution from energy activities account for 6% of the total 50 million annual global deaths.
The multiple indirect health effects from energy related environmental pollution are even more difficult to assess. Acidification of land areas and waters can result in damage to both terrestrial and aquatic ecosystems. It can affect the mobility in the ecosystem of some heavy metals such as mercury. Lake acidity and increased mercury concentrations in lakes are factors that influence the quantity of mercury accumulating in fish and entering the human food chain.
Although ongoing exposure to fossil fuel related toxic pollutants through polluted air and contaminated water and food is a daily experience, there is a widely held public belief that nuclear power presents the greater health risk. Extreme concerns about radiation are demonstrated by a common conviction that plutonium - in spent fuel and from reprocessing - can be significantly more harmful than toxic pollutants, with some people believing it is the most hazardous substance on earth. Plutonium is not very radioactive - as a long lived material with a half-life of more than 24 000 years it decays very slowly. Its radiation cannot penetrate even a sheet of paper. As it is not highly soluble in most forms, it is not very hazardous when small quantities are ingested in liquids, where the major portion passes unabsorbed through the body.
In fact, plutonium can be extremely hazardous to health only when finely dispersed in sufficient concentration and inhaled, when - as with very small particles of inhaled toxic pollutants - it passes through the lung tissue into the blood. Fortunately, a scenario to disperse sufficient amounts of plutonium, which is transported in strong structural containers, into the atmosphere to cause significant health effects in populations would be extremely difficult. By contrast, many of today's energy related toxic pollutants, including easily inhaled particulates that are the main mortality factor due to fossil fuels, have high potential health effects.