All of the situations discussed in the preceding section apply to planned ‘nor­mal’ exposures. On rare occasions, however, abnormal situations arise, the most recent being that at Fukushima in Japan. This happened some twenty five years after the Chernobyl accident, which occurred on 26 April 1986 during a low power engineering test of their Unit 4 reactor. At the time of writing, little is known about the events at Fukushima, but it is useful to review what has been learned from Chernobyl.

The Chernobyl site is located in present-day Northern Ukraine, some 20 km south of the border with Belarus and 140 km west of the border with the Russian Federation. The accident was caused by the improper operation of the reactor, which itself had severe design flaws, allowing an uncontrollable power surge to occur. This resulted in successive explosions that severely damaged the reactor building and completely destroyed the reactor. The accident caused the uncontrolled release of large quantities of radioactive substances into the air for about 10 days. The radioactive cloud dispersed over the entire northern hemisphere and deposited substantial amounts of radioactive material. At the site itself, two workers died from injuries, and approximately 600 workers responded within the first day to the immediate emergency, including staff at the plant, firemen, security guards, and staff of the local medical facility. The dominant exposures for these personnel were external irradiation of the whole body at high dose rates, and beta-irradiation of the skin. Internal contamina­tion was of relatively minor importance, and neutron exposure was insignif­icant. As was to be expected, a very considerable effort has since been expended to follow up on the human consequences of this major nuclear disaster, and the latest findings are those of UNSCEAR.24

Cases of acute radiation syndrome (ARS) occurred among the plant employees and so-called ‘first responders’ but not among the evacuated populations or the general population. The diagnosis of ARS was initially considered for 237 persons, based on symptoms of nausea, vomiting and diarrhoea. The diagnosis was confirmed in 134 persons. There were 28 early deaths (first four months), primarily (95%) where whole-body doses were in excess of 6.5 Gy. Underlying bone marrow failure was the main contributor to all deaths during the first two months, in spite of attempts to save them with bone marrow transplants. Skin doses exceeded bone marrow doses by a factor of 10 to 30, and many ARS patients received skin doses in the range of 400-500 Gy. Radiation damage to the skin aggravated other conditions, and this was considered to be a major contributor to at least 19 of the deaths. Such damage significantly increased the severity of the ARS, especially when skin burns exceeded 50% of the body surface area and led to major infections. Since then, 19 ARS survivors have died (up to 2006), but their deaths have been attributed

to various causes, and usually not associated with radiation exposure. Skin injuries and radiation-induced cataracts are, however, major lasting clinical impacts for the ARS survivors.

In 1986 and 1987, some 440 000 recovery operation workers were used at the Chernobyl site, and more ‘recovery workers’ were involved in various activities between 1988-1990. Collectively, about 600 000 persons (civilian and military) received special certificates confirming their status as recovery operation workers (unfortunately also known as ‘‘liquidators’’). About 240 000 were military servicemen. The average effective dose received by these recovery operation workers between 1986-1990, and mainly due to external irradia­tion, is estimated to have been about 120 mSv. The recorded worker doses varied from > 10 mSv too 1 Sv, although about 85% of the recorded doses were in the range 20-500 mSv. (Uncertainties in the individual dose estimates vary from > 50% up to a factor of 5, and the estimates for the military per­sonnel are suspected to be biased towards high values.) To date, there is some evidence of a detectable increase in the incidence of leukemia, primarily based upon results from the Russian Federation, and of cataracts among those who received higher doses, but there is no evidence of other health effects than can be attributed to radiation exposure.

With regard to the public, the number of evacuees was about 115 000, consisting of about 25 000 persons from Belarus, 200 from the Russian Fed­eration and 90 000 from the Ukraine. The areas from which people were evacuated form what is called the ‘‘exclusion zone’’, which includes not only the 30 km zone, which is the area within a 30 km radius centred on the location of the Chernobyl reactor, but also highly-contaminated areas adjacent to the 30 km zone and more distant areas where high levels of radionuclide deposition density were measured.

Two radionuclides, the short-lived iodine-131 (with a half-life of 8 days) and the longer-lived caesium-137 (with a half-life of 30 years), were particularly significant for the radiation dose they delivered to members of the public. In the former Soviet Union the contamination of fresh milk with iodine-131, and the lack of prompt countermeasures, led to high thyroid doses, particularly among children. The thyroid doses received by the evacuees varied according to their age, place of residence, consumption habits, and date of evacuation. For many pre-school children the doses to the thyroid were well in excess of 1 Gy. It is therefore not surprising that there has been a substantial increase in thyroid cancer incidence amongst those exposed as children or adolescents in Belarus, the Russian Federation, and the Ukraine since the Chernobyl accident, and this increase has shown no signs of diminishing (up to 20 years after exposure). Amongst those under the age of 14 years in 1986, 5127 cases (for those under the age of 18 years in 1986, 6848 cases) of thyroid cancer have been reported between 1991-2005 for the whole of Belarus and Ukraine and the four more affected regions of the Russian Federation. By 2005, 15 cases had proved fatal.

In the longer term, mainly due to caesium-137, the general population was also exposed to radiation externally from radioactive deposition and internally from consuming contaminated foodstuffs. The resulting radiation doses were relatively low, however, partly because of the countermeasures taken. Excluding doses to the thyroid, the mean effective doses due to external irra­diation were estimated to have been about 30 mSv for the Belarusian evacuees, about 25 mSv for the Russian evacuees, and about 20 mSv for the Ukrainian evacuees. These values were at least 10 times smaller than the corresponding numerical values of thyroid doses resulting from internal irradiation. The mean effective doses due to internal irradiation were estimated to have been about 6 mSv for the Belarusian evacuees, about 10 mSv for the Ukrainian evacuees, and about 10 mSv for the Russian evacuees. These values were at least half of the corresponding effective doses due to external irradiation.

Among those exposed in utero and as children, no persuasive evidence has apparently accrued to suggest that there is a measurable increase in the risk of leukemia due to radiation exposure. This is not unreasonable, because the doses involved were generally very small, and therefore epidemiological studies would lack sufficient statistical power to observe any effect, had there been one. Overall, therefore, the average effective doses, due to both external and internal exposures, received by members of the public during 1986-2005 were about 30 mSv for the evacuees, 1 mSv for the residents of the former Soviet Union, and 0.3 mSv for the populations of the rest of Europe.

More recently, on 11 March 2011, an earthquake and accompanying tsunami struck the coastal area of Japan and caused major damage to the Fukushima Dai-ichi nuclear power plant, which consists of six boiling water reactors, three of which were operating at the time. Three staff were killed as a result of these events — not related to radiation exposure. When the earthquake struck the reactors automatically shut down and the emergency cooling systems were activated but one hour later these were all damaged by a wall of water some 14 m high as a result of the accompanying tsunami. (The tsunami itself was responsible for the deaths of over 26 000 local residents.) Hydrogen explosions subsequently badly damaged the control rooms of the three operating reactors (Units 1, 2 and 3) and there were problems with the spent fuel pool of Unit 4, which subsequently led to a fourth hydrogen explosion. There have been no recorded cases of ARS amongst the staff dealing with the emergency, and none are expected.

Local residents were evacuated out of the area in a staged manner up to a radius of 20 km around the site, the evacuation being compounded by evacuees from the tsunami. The principal nuclides of concern were again those of iodine and caesium. Residents within a 20-30 km radius were instructed to shelter indoors. In contrast to Chernobyl, the radionuclides released were not widely distributed and considerable precipitation subse­quently occurred due to snowfall. Protective actions were immediately implemented with regard to the consumption of contaminated water and foodstuffs and the screening of children, in particular, for iodine con­centrations in the thyroid gland was undertaken. More detailed information is still awaited but clearly the major long-term impact for the local popu­lation, having experienced a severe earthquake, tsunami, and a nuclear accident, will be psychological.

Radiological Protection of Workers and the General Public

3 Conclusions

The current system of radiological protection for people has been developed over a long period of time, and has involved an enormous body of scientific, medical and cultural information. All of these areas are still actively pursued, and the system reviewed and revised. In terms of application, an enormous amount of experience has now been gathered over many decades. Exposures of people to ionizing radiation may be through medical diagnostic or therapeutic exposures, of which there must be a vast number undertaken daily throughout the world; through exposures at work in all forms of industry that may involve radioactive or radiation sources; or through public exposures arising from releases from both nuclear and non-nuclear establishments. All of these exposures, and the sources leading to them, are controlled on the same scientific basis and interpretation, and on the advice of the same international committee-the ICRP, and its extensive support. If there was something ser­iously amiss with this system, then it would by now have come to light. Not that there is any reason to be complacent, as the recent incident at Fukushima, and the 25th anniversary of Chernobyl serve to remind us, accidents can happen, as they can in any industrial endeavor. But it should provide a high degree of assurance to anyone that is concerned about radiation safety and our ability to manage it safely that, whatever the source of exposure or the category of people exposed, the actions taken to safeguard human health are based on a wealth of experience that is unequalled in any other field.

Issues in Environmental Science and Technology, 32 Nuclear Power and the Environment Edited by R. E. Hester and R. M. Harrison © Royal Society of Chemistry 2011

Published by the Royal Society of Chemistry, www. rsc. org

“At present there are over 440 commercial nuclear power reactors operating in 30 countries, with 376 000 MWe of total capacity. In total, they provide about 15% of the world’s electricity. ш The only country that developed nuclear reactors with no military link was Canada, whose ZEEP (Zero Energy Experimental Pile) formed the basis of Canada’s indigenous nuclear reactor design — CANDU — which used natural as opposed to the more expensive, enriched uranium. However, the first reactor which formed part of the Manhattan projects’ attempt to produce plutonium for the atomic bomb, involved scientists from Canada, Britain and France. Although Canada did not develop its own nuclear weapons programme after the war, it did sell plutonium to the UK in order to fund the Canadian civilian reactor programme. ivChicago Pilel. The term ‘‘nuclear reactor’’ was not used until 1952.

[3]The focus on fast breeder reactors (FBR) in these early years reflected a concern that sourcing all of the uranium to power the world’s nuclear reactors was going to prove extremely difficult. However, they all turned out to be too costly to operate and were beset by technological diffi­culties, as well as the heightened proliferation risk that would accompany a ‘‘plutonium econ­omy’’. Subsequently large uranium deposits were discovered in Canada and Australia negating the original rational for FBRs.

[4] Winston Churchill opposed the idea, suggesting to Roosevelt that he stop Bohr travelling to the Soviet Union to make his case, even suggesting at one point that he should be put under house arrest.4

™The plan failed for a number of reasons, including the refusal of the USSR to allow inspections on its territory, as well as the US position that it would not destroy its nuclear arsenal until it was convinced of the efficacy of international control and monitoring procedures. The talks collapsed two years after they had begun and the UN AEC abandoned. It would be a decade before a replacement body, the IAEA, was conceived and then shorn of any pretensions to global over­sight of nuclear matters envisaged by Oppenheimer and Ascheson.5

[6]Before the Second World War, France had invested the most money of any country in the world in the attempt to develop the first nuclear reactor, but German invasion and dispersion of its scientists meant that this honour was to become Enrico Fermi’s, as part of the Manhattan Project The lack of financial resources in the immediate aftermath of the Second World War meant that French nuclear research fell well behind that of the British and Americans.

[7]The UK’s most serious nuclear accident occurred as a result of a fire in Windscale Pile 1 in 1957. Even today, it remains a decommissioning headache in both financial and technological terms. The fire received very little media and public attention at the time, reflecting the tight security and secrecy that enveloped the nuclear industry in these early years of IES development. Unlike today, reactor designs were not subject to public scrutiny and/or parliamentary oversight.

[8] This was a forerunner of the RBMK reactors, the same design as the reactors at Chernobyl.

[9]Rickover became known as the ‘‘Father of the Nuclear Navy’’.

x111 The pressure on reactor designers to keep the costs down, it is claimed, led to compromises on safety, especially given the intense competition from coal and oil-fired power stations.16

[11]A prototype BWR, Vallecitos, ran from 1957 to 1963.

[12]Not all reactors were light water reactors. Canadian reactor development headed down a quite different track, using natural uranium and heavy water as both a moderator and coolant. The first of these ‘‘CANDU’’ units started up in 1962 and they were the first reactors to not have a military connection. Along with Canada, Germany and Sweden followed this heavy water/ natural uranium route given their desire not to have to rely on foreign states for costly enrich­ment services.

[13] It was not until 1995 that plutonium production ceased.

[14] Eventually it estimated that a programme of twelve nuclear power stations with a total capacity of between 1400-1800 MW would be on line by 1965 (ref. 22).

[15] There were technical problems during operation, much longer construction times than planned and as a result a much greater cost of electricity than budgeted.

[16] Led by the then chief economist of the NCB, Fritz Schumacher, who went on to penn the environmentalist classic Small is Beautiful.

** The Prime minister at the time, Harold Wilson, and his Energy Secretary, Tony Benn, were both pro nuclear. Benn was convinced of the case for civil nuclear power based on the ‘‘beating swords into ploughshares” sentiment. A position Benn has since retracted, arguing that he was misled when Minister of Technology about the costs of nuclear energy, ‘‘I was told, believed and argued publicly that civil nuclear power was cheap, safe and peaceful and it was only later that I learned that this was all untrue since, if the full cost of development and the cost of storing long-term nuclear waste is included in the calculations nuclear power is three times the cost of coal when the pits were being closed on economic grounds’’.26

[18] The regulatory structure was also more permissive with regard to nuclear power than exists today, reflecting in part the deferential culture toward experts and scientists in the 1950s. This scrutiny as it existed was carried out by the UK Atomic Energy Authority internal safety branch. It relied in essence on a ‘‘staged operating experience to demonstrate that if the reactor worked, then it must be safe after all’’ which is in stark contrast to the risk-based approach adopted by contemporary regulators.28

[19]This was increased to $7 billion in 1988.

mnAs Laurent Striker, senior vice president at Electricite de France, commented ‘‘France chose nuclear because we have no oil, gas or coal resources’’.

[21]Indeed, in December 2009 the United Arab Emirates accepted a bid from a South Korean consortium to construct four APR1400 reactors by 2020. China will reportedly invest $175 billion over the next ten years on developing the 130 square-kilometre Haiyan ‘‘Nuclear City’’.

[22] During this period of expansion the uranium-based thermal reactor were seen by the nuclear industry as very much the first ‘‘primitive” form of reactor,37 in comparison with more advanced fast breeder reactors which are designed to ‘‘breed’’ more plutonium than they can consume as fuel (some breeders can produce 30% more fuel than they use). India, Russia, Japan and China currently have operational fast breeder reactor programmes. The UK, France and Germany have effectively shut down theirs.

[23] Policy changes meant that there was a shift from ‘‘military uses first’’ to ‘‘combining military and civilian uses’’, this led to a state Ministry being reorganized and renamed to become China National Nuclear Corporation (CNNC) in 1989 (ref. 44).

[24] Some industry insiders suggest that the problem was exacerbated by the introduction post­privatization of a non-technical management, whose focus was on short-term profits, ‘‘with no understanding of the need to technically maintain the assets and the skill base or the long-term needs of the business, which in turn led to the massive shareholder losses’’.62

xxvin The ageing Magnox stations with less than 10 years’ lifespan could not be sold and were given to BNFL.

[26] Exacerbated by the lack of a long-term waste disposal route and a regulatory regime that hindered rather than facilitate new nuclear plants.

[27] However, even a doubling of existing nuclear capacity will only reduce GHG emissions by 8% given that electricity is only a third of total energy production.

““Whilst it is clear that nuclear power is not a completely carbon-free energy source (e. g. both uranium mining and the construction of the nuclear plant relies on fossil fuel energy), it is substantially better than either coal or gas.

[29] In some countries (such as Finland), potential increases in natural gas prices played a key role in the decision to proceed with new nuclear. In addition, nuclear power was portrayed as the cheapest low carbon option.73 In May 2002, the Finnish parliament voted on the new reactor and decided in favour, becoming the first OECD country to decide to build a new nuclear reactor for several years. The vote was very close, however, with 107 votes for and 92 against.

xxxm Bickerstaff et al. describe the British public attitude toward new nuclear as ‘‘reluctant accep­tance”, i. e. when presented against the impending danger of climate change, the risks of nuclear power seem acceptable even to people who are a priori hostile to nuclear power. While science itself is trusted, the government institutions are seen as ‘‘unreliable, secretive and failing to execute their proper duties (or functions) to serve the public interest’’.84

[31]Whilst a recent report from the International Atomic Energy Agency (IAEA) International Status and Prospects of Nuclear Power suggested that there are some 65 countries currently without nuclear power plants who ‘‘are expressing interest in, considering, or actively planning for nuclear power’’ there are technical barriers to at least 17 of those proceeding, due to the fact that they have electricity grids of less than 5 GW which are ‘‘too small to accommodate most of the reactor designs on offer’’. Moreover, many of these countries do not have the ‘‘necessary nuclear regulations, regulators, maintenance capacity, or the skilled workforce to run a nuclear plant. The head of France’s Nuclear Safety Authority has estimated that it would take at least 15 years to build the necessary regulatory framework in countries that are starting from scratch’’.85 There are also doubts as to whether grids of up to 10 GW could cope with nuclear power generation.

[32]For many developing countries the language of national economic development is often invoked as a rationale for investing in nuclear energy, even in countries with no history of the technology.

mvi Russia’s neighbour, Ukraine, is currently building two reactors and planning as many as 11 more by 2030 as it seeks to reduce its dependence on energy from Russia, particularly in light of the disputes over gas in 2006 and 2009. The strategy also envisages completing the construction by 2017 of two reactors at Khmelnitsky, work on which has been halted since 1990. mvnA recent MIT report on the Future of Nuclear Power pointed out that given increasing demand, to increase nuclear powers’ share from its present 17% of world electricity to just 19% by 2050 would require a near-trebling of nuclear capacity: 1000-1500 large nuclear plants would have to be built worldwide.

[34] Prompt decommissioning means that site knowledge is retained and can be used to assist in the decommissioning process.

• Availability of money to perform decommissioning may be limited.

• Financial depreciation makes it attractive to defer large expenditure.

• Radioactive decay means that decommissioning may be easier, and therefore cheaper, if it is deferred. For some wastes, the radioactive decay may result in material being reclassified as a less onerous waste form, so requiring less treatment and incurring reduced costs.

• A final disposal route for wastes may not be available. This may require construction of intermediate facilities incurring costs and using natural resources that would not otherwise be required; these facilities themselves will require decommissioning at the end of their lives. It may therefore be desirable to postpone decommissioning until a final disposal route is available.

Time

[35] Fuel recycle plants at Sellafield

• Fuel enrichment plant at Capenhurst

[36] The waste form. Wastes are conditioned (see section 3.3.5) prior to disposal to make them more stable. For example, highly active raffinate

[37] Site selection for GDF construction will be based upon community volunteerism and the siting process will take several years (see section 3.3.3).

(ii) The GDF will be tailored to the UK baseline inventory which is both large by volume and radioactivity, and complex in character due to the

[38] HLW: The highly active raffinate (HAR) solution from fuel reprocessing (see section 2.2) produces excessive heat and radioactivity and is highly unstable. Consequently, HAR is evaporated to reduce its volume to form highly active liquor (HAL). The HAL is then stored in water cooled tanks to permit heat dissipation and radioactive decay. After storage, the HAL is homogenised, immobilised, and conditioned in a

[39] Planned exposure situations, which are situations involving the planned introduction and operation of sources, and include situations that were previously categorised as ‘‘practices’’. These include situations that are anticipated to occur (in other words, ‘‘normal’’ exposures) as well as exposures that are not anticipated to occur but may occur (‘‘potential’’ exposures), such as accidents. In the latter case, although the situation was not planned to occur, the situation itself can be planned for, although not necessarily in great detail. These days such potential exposures can include a variety of possibilities, from accidents that may