Scientific interest in understanding climate changes due to greenhouse gases began in the late nineteenth century with the Swedish chemist Svante Arrhenius, and such interest has developed considerably since that time. The history of such developments is described by the science historian Spencer R. Weart in his book The Discovery of Global Warming (Weart, 2008). Today there is no doubt that global warming, first noticed during the industrial revolution, is due to the increase of greenhouse gases, mainly CO2 from anthropogenic sources, of which electricity generation is a part. The effort now is being put into determining the relationship between CO2 in the atmosphere and the increase in air temperature at soil level.

The United Nations sponsored Intergovernmental Panel on Climate Change (IPCC), created in 1987, is currently the international organization responsible for reviewing and consolidating research on climate change and its effects. Since all nations share the atmosphere, climate change affects everyone, so control of carbon emissions is a global bonus. Any efforts made to reduce such emissions by using nuclear power instead of fossil fuels is a benefit for the whole world.

The IPCC produced major assessments on the climate change situation in 1990, 1995, 2001 and 2007. The first report underscored the seriousness of the risks associated with climate change and it was the driver for the 1992 UN Earth Summit in Rio de Janeiro, which led to the UN Framework

Convention on Climate Change (UNFCCC) and, later, in 1997, to the Kyoto Protocol. A clash between the requirements of developing and developed countries delayed the entering into force of the Protocol to 2005 and limited its validity to 2012. The Protocol established that developed countries should achieve an average 5.2% cut in CO2 emissions by 2008-2012, when compared to 1990 levels (UN, 1998). The Protocol created an emissions market and defined the so-called Clean Development Mechanism (CDM) which is non-applicable to nuclear projects. Developments expected after 2012 are not yet well defined.

One of the major worldwide advantages of nuclear power is its limited greenhouse gas emissions and its therefore corresponding contribution to a reduction in climate change (UIC, 2001). The nuclear fission reaction is anaerobic, i. e. it does not need air to generate energy, as is the case with fossil fuels. Fossil energy may be needed in the nuclear fuel cycle, for uranium mining and milling, conversion, enrichment, fuel fabrication, reprocessing and waste deposition and related transportation activities. The fabrication of components, construction and assembly of a nuclear power plant and its dismantling need fossil energy in the same way as other electricity generat­ing installations of a comparable size. The operation of a nuclear power plant is, however, generally free from carbon emissions, except for some safety and ancillary equipment such as emergency diesel generators, which have to be tested periodically, and boilers for heating sanitary and process water.

The release of CO2 from the different sources of generating electricity has received considerable attention. Up to the year 2000, it was estimated that nuclear energy could release up to 16 t CO2/GWh (Spadaro, 2000), while the release from coal and natural gas could amount to 1100 and 450 t CO2/GWh, respectively. These data are approximations that have been recently refined. First, there are differences in the type of coal and the thermal efficiency of the plant being considered: lignite can produce 1200 t CO2/GWh, while hard coal is limited to 1070 t CO2/GWh and can even go down to 974 t CO2/GWh for modern high-efficiency plants. Figures for gas combustion in conventional stations can be 650 t CO2/GWh, down to 450 t CO2/GWh for modern combined cycle plants. There are also variations in nuclear power plants mainly due to the enrichment process used: the gas diffusion process needs close to 50 times the energy needed in the gas ultracentrifugation process, and it can be as low as 5 t CO2/GWh. The data quoted here are taken from a number of different sources (NEA, 2008; Richter, 2010).

The data quoted for nuclear power include so-called plant life-cycle emis­sions, made up of the CO2 released in making the steel and concrete used in the plant, as well as that generated during dismantling and radioactive waste management, divided by the energy produced by the plant during its expected lifetime; to this is added the emissions involved in fuel cycle activities, including transportation and the limited direct emissions from operation. Longer-term operation of nuclear power plants therefore reduces their carbon footprint. This concept also applies to other carbon-free power sources, such as wind and solar power; as for nuclear power, the CO2 foot­print during operation of these sources is limited to maintenance and ancil­lary operations. Within this context, CO2 emissions from wind turbines are comparable to those of nuclear power, while those of solar power are two to three times larger.

With the basic data provided above, it is possible to determine the CO2 emissions that are avoided by using nuclear power instead of coal or gas. For one GWe nuclear plant operating with a 90% capacity factor, 7.6-9.3 million tons and 3.5-6.2 million tons of CO2 are effectively saved per year compared to that generated if the same energy were produced by coal and gas plants, respectively (depending on the technology used and the type of coal). The CO2 avoided carries a monetary value when using the Cap and Trade scheme already practised within European Union member states.

A recent report produced by the United Kingdom Committee on Climate Change states that ‘nuclear generation in particular appears likely to be the most cost-effective form of low-carbon power generation in the 2020s (i. e. before costs of other technologies have fallen), justifying significant invest­ment if safety concerns can be addressed’ (CCC, 2011). Similar results have been found by the International Energy Agency in its economic evaluation of ways to reduce the carbon content of the atmosphere to 500 ppm by 2050.

KERENA (earlier known as SWR-1000) is an evolutionary boiling water reactor based on the experience gained from the proven engineering of current generation BWR plants supplemented by an innovative approach. The current final basic design of KERENA is part of a strategic partnership between AREVA and the German utility E. ON Kernkraft. In KERENA, safety systems have been simplified by introducing passive safety systems, and most nuclear safety functions are performed by active systems with a passive system as backup. The core height has been reduced to promote natural circulation, and the eight reactor water recirculation pumps are the so-called wet-motor pumps, where the electric pump motor is situated inside the reactor coolant pressure boundary.

In early years, two quite distinct approaches to safety design and licensing were developed. The first has been associated with Frank Farmer (Farmer, 1967), who argued that the fundamental rule of engineering design requires recognizing the desirable inverse relationship between accident frequency and expected accident consequences. This method was elaborated by E. Siddall and others and then applied to the licensing of the first large-scale CANDU power plant. In this formulation, accidents of all types can be presented (Meneley, 1999) on a frequency versus consequence plot (Fig. 10.6). The initial Canadian approach was later modified to an intermediate

method combining the initial probabilistic formulation with specific require­ments to be applied separately to systems used to operate the plant, and secondly to an independent set of so-called Special Safety Systems whose only functions were to respond to abnormal conditions so as to shut off the chain reaction, close the containment envelope, and continue cooling the fuel. The current licensing regime in Canada continues in this same style, even though many detailed requirements have been added to the original concept.

The second approach to licensing was to first establish a set of so-called General Design Criteria for Nuclear Power Plants (USNRC, 2010) and then to judge licence applications in terms of their success in meeting these criteria. In this approach there was no explicit appeal to accident frequency, even though the underlying logic can be interpreted as such. This approach is still used in the USA and in many other countries; however, it has been augmented in many respects, especially through the introduction of speci­fications requiring detailed probabilistic analytical tools. This probabilistic approach builds on the work presented in the original report (Rasmussen et al., 1975). Figure 10.7 shows a very brief indication of the original results. Note that it estimated the risk of operation of 100 large nuclear plants to be similar in magnitude to the existing risk of fatalities caused by meteorite strikes. Other naturally occurring risks were found to be several decades larger. In spite of this highly reassuring finding, fear of nuclear energy has for more than 25 years barred the further adoption of this safe, economical, and sustainable energy source in the United States, and largely in Western Europe. There is a fundamental lesson in this experience for nations that choose nuclear energy and seek to justify that choice to their citizens (see Section 10.3.4).

The extensive background experience in setting and then meeting safety standards in operation, as described in this section, has produced a well — codified set of international standards and guides for safe operation that can be used with confidence by organizations ready to join in the worldwide nuclear energy enterprise.

In order to establish a new nuclear energy program, a country must, of course, first establish a sound knowledge base so that decisions about the direction to be taken are sound and in the interest of the nation concerned. Even with all possible goodwill on the part of outside organizations, they are very unlikely to fully understand the goals of any nation as well as do its native inhabitants. Fortunately, the number of channels of communica­tion is vast, and opportunities for education of staff are excellent.

328 Infrastructure and methodologies for justification of NPPs

The 1986 accident at the Chernobyl nuclear power plant in the former Soviet Union was the most severe such accident in the history of civilian nuclear power and due to its perceived radiation consequences has become a nemesis for NPPs. However, while the accident undoubtedly was cata­strophic in nature, and contaminated vast areas of European land, its radi­ation-related health consequences were fortunately limited, as can be observed in the maps of reference (De Cort et al., 1998).

Since the fateful accident occurred, the international community has made unprecedented efforts to assess the magnitude and characteristics of its radiation-related health effects (IAEA, 1986a, 1988, 1991; Gonzalez, 1990, 1996a, 1996b, 2007; Konstantinov and Gonzalez, 1989). The results of those initiatives were synthesized at an international conference on the theme ‘One decade after Chernobyl: summing up the consequences of the accident’, which was held in Vienna in 1996 (IAEA, 1996b). Broadly similar conclusions were reached by the Chernobyl Forum launched by eight organizations of the United Nations system and the three most affected States to generate authoritative consensual statements on the environmen­tal and health consequences attributable to radiation exposure and to provide advice on issues such as environmental remediation. The work of the Chernobyl Forum was appraised at an international conference on the theme ‘Chernobyl: looking back to go forwards; towards a United Nations consensus on the effects of the accident and the future’, which was held in Vienna in 2005 (IAEA, 2008a). The international consensus has been recently reported by UNSCEAR as follows (UNSCEAR, 2009):

1. A total of 134 plant staff and emergency workers received high doses of radiation that resulted in acute radiation syndrome (ARS), many of them also incurring skin injuries due to beta irradiation.

2. The high radiation doses proved fatal for 28 of those people in the first few months following the accident.

3. Although 19 ARS survivors had died by 2006, those deaths had different causes that usually were not associated with radiation exposure.

4. Skin injuries and radiation-related cataracts were among the main sequelae of ARS survivors.

5. Aside from the emergency workers, several hundred thousand people were involved in recovery operations but, apart from indications of an increase in incidence of leukaemia and of cataracts among those who received higher doses, there is to date no consistent evidence of health effects that can be attributed to radiation exposure.

6. A substantial increase in thyroid cancer incidence among persons exposed to the accident-related radiation as children or adolescents in 1986 has been observed in Belarus, Ukraine and four of the more affected regions of the Russian Federation. For the period 1991-2005, more than 6000 cases were reported, of which a substantial portion could be attributed to drinking milk in 1986 contaminated with iodine — 131. Although thyroid cancer incidence continues to increase for this group, up to 2005 only 15 cases had proved fatal. Figure 11.8 presents the thyroid cancer incidence among people in Belarus who were chil­dren or adolescents at the time of the Chernobyl accident, for 1986­1990, 1991-1995, 1996-2000 and 2001-2005 (UNSCEAR, 2009).

7. Among the general public, to date there has been no consistent evidence of any other health effect that can be attributed to radiation exposure.

11.8

Thyroid cancer incidence among people in Belarus who were children or adolescents at the time of the Chernobyl accident.

In sum, based on 20 years of studies, UNSCEAR reconfirmed that, essen­tially, persons who were exposed as children to radioiodine from the Chernobyl accident and the emergency and recovery operation workers who received high doses of radiation are at increased risk of radiation — induced effects. Most area residents were exposed to low-level radiation comparable to or a few times higher than the annual natural background radiation levels and need not live in fear of serious health consequences.

Notwithstanding the above, it is clear that the Chernobyl accident has had and will continue to have an enormous impact on the development of nuclear energy and will be a continued prejudice in any assessment of its justification [Gonzalez, 2007].

Since its birth, the IAEA’s safeguards work has included[26]:

• Verifying that countries are not using nuclear material and nuclear technology for non-peaceful purposes

• Setting the standards and guidelines for safeguarding nuclear material and facilities

• Fulfilling its role as the guardian of the nuclear non-proliferation treaty

• Assisting the international community in nuclear disarmament efforts.

To fulfil its mandate, the Secretariat has assigned the Department of Safeguards with organizational responsibility for safeguards implementa­tion. In practical terms, the Department of Safeguards implements monitor­ing and verification activities worldwide in over 900 facilities and locations outside facilities (LOFs).[27] While covering the entirety of a State’s nuclear fuel cycle, its efforts consider the strategic value of those types of nuclear material and activities in a NNWS that are the most crucial and relevant to nuclear weapons manufacturing. It publishes the results of its activities annually in a Safeguards Implementation Report.[28]

Keeping in mind that there are three major infrastructure milestones[29] in the Milestones publication (IAEA, 2007a) for the development of a nuclear power programme, stakeholders involved with any of the milestones may find themselves better equipped and more effective in their assigned capac­ity when they consider the full scope and nature of the IAEA’s safeguards work. This subsection briefly discusses that work in the context of the Safeguards and Verification Pillar.[30]

Safeguards have evolved from their early focus on safeguarded nuclear material at the facility level, to today’s concept which reflects development and implementation of a safeguards approach at the State level.[31] In the evolution of the safeguards approach over the last several decades, includ­ing transitioning the application of safeguards from a facility level to the State level, there were external and internal IAEA factors driving the introduction of new tools and safeguards measures. For an authoritative account, two recommended sources of information on the IAEA’s historical transition in safeguards and how it was implemented and is being imple­mented today have been provided by Jennekens (1970) and by an IAEA Department of Safeguards document covering 1991-2005 (IAEA, 2005b, Section C).

For introductory purposes, the general sequence of developments in a State’s safeguards system will be described starting from the moment a

State decides to pursue a nuclear energy option for peaceful purposes. In terms of a chronology of events, what follows is a hypothetical sequence of safeguards-relevant events that a ‘newcomer’ State may come to experi­ence. Bear in mind that the sequence described below is for illustrative purposes only, and there may be many variations in an actual case.

In theoretical terms, assuming a State has not yet acceded to the NPT, it may take appropriate action domestically and internationally for consider­ing such an undertaking. Should the State be contemplating development of a nuclear power infrastructure, the State will very likely assess its priori­ties and presumably decide positively on the importance of the NPT rela­tive to its non-proliferation goals and objectives. Whether a State accedes to the NPT or not, their decision will inevitably impact the perception of many regional and international stakeholders regarding the State’s trans­parency and openness.

For a State without a safeguards agreement in force, the IAEA will work closely with the State’s representatives to draft and bring one into force. If the reference State is a Party to the NPT, the safeguards agreement will be comprehensive in nature and modelled on INFCIRC/153 (Corrected) (IAEA, 1972). Any State with a safeguards agreement may also conclude a protocol additional to its safeguards agreement with the IAEA (herein­after referred to as an ‘additional protocol’).[32] While it remains the sover­eign decision of the host State, if requested the IAEA will advise and provide available support to enable a State to conclude an additional pro­tocol (AP) to their safeguards agreement at the same time (or at a later date depending on the State’s circumstance). In respect of drafting the safeguards agreement (and AP), the State and the IAEA will conclude Subsidiary Arrangements[33] which specify how the measures included in the CSA (and AP) are to be implemented. Subsidiary Arrangements to

safeguards agreements consist of a General Part, applicable to all common nuclear activities of the State concerned, and a Facility Attachment, pre­pared for each facility in the State and describing the arrangements specific to that facility.

Once a CSA is in force, the State is obligated to establish a state system of accounting for and control of nuclear material (SSAC) if it has not already done so.[34] In this regard, there are two different contexts to the use of the term SSAC. One refers to the National Authority assigned responsi­bility as the formal technical interface for safeguards implementation with the Agency and facility operators. The second refers to the system of nuclear material accounting and control procedures required by the National Authority and implemented by facility operators. The concept is graphically presented in Fig. 13.1. With regard to the National Authority assigned as the SSAC, among its many initial responsibilities, the newly established SSAC will address the preparation and transmission of the State’s initial report (concerning the inventory of nuclear material and facilities) to the IAEA.[35] If an AP is in force at the time, the preparation and submission of initial AP declarations are also required.

Early consultation with the IAEA can facilitate this process to the benefit of both Parties. Experience shows that it is a good practice if the SSAC is involved early in the process, for example prior to or during the develop­ment of the Subsidiary Arrangements. In some NNWSs, it is an office in the Ministry of Foreign Affairs or equivalent that is designated as the SSAC, negotiates the Subsidiary Arrangements, submits the initial report and undertakes to fulfil other SSAC responsibilities. In other countries, a depart­ment or section in the Ministry of Science and Technology or equivalent is the SSAC which seeks to fulfil the requisite obligations. There are any number of considerations that go into such a decision and each State is expected to factor in its own national interests and needs. Examples may include current or proposed national laws, policies and regulations relevant to safeguards implementation; relevant foreign policies; technical compe­tency of the ministry or department/section; and financial and other resource availability/constraints. The essential point here is that whether a State has no nuclear material and facilities, or they possess a more developed nuclear fuel cycle, having a technically capable and properly resourced SSAC is a requirement of fundamental importance. Regardless of which national authority is designated as the SSAC, the State’s point of contact for safe­guards will be identified in the relevant Subsidiary Arrangements and will benefit by being involved early in the process.

With regard to the system of nuclear material accounting and control procedures, if there are small quantities of existing nuclear material in the State, the State may already have an operational nuclear material account­ing and control system. If one is not in place, concurrent with the activities involving the preparation of the initial inventory declaration, the State and the relevant operators establish or implement a nuclear material accounting and control system.[36] In keeping with the IAEA’s mandate under its Statute, the IAEA takes account of all safeguarded nuclear material, including enriched uranium, plutonium and uranium-233 in countries with a CSA. Other types of nuclear material subject to safeguards verification include thorium, natural uranium, and depleted uranium, the latter of which is commonly used, for instance, as shielding of radiation sources in hospitals, industry and agriculture.[37]

Following the submission, if any nuclear material is declared, the SSAC works closely with relevant nuclear operators to prepare for the IAEA’s initial verification of the State’s nuclear material inventory. During this period, the IAEA is reviewing the State’s declarations and, as appropriate, assessing the correctness and completeness of the submittal (s). In some instances, the SSAC may receive one or more IAEA requests for clarifica­tion or further information. The more technically capable a SSAC is at this point, the more easily it will be able to respond accordingly. Good com­munication between the parties is always a recommended priority, but it is especially important during this stage of the process.

In respect of the State’s initial inventory declaration, the SSAC will then undertake to routinely submit accounting and operating reports to the IAEA as specified in the respective Facility Attachment (part of the Subsidiary Arrangements). The relevant accounting reports and operating records in the submittals usually originate from the facility operator’s system of accounting for and control of nuclear material. Nevertheless, as the CSA is a binding instrument between the IAEA and the State, it is the SSAC that is responsible for assuring the correctness and completeness of the submittals to the IAEA. This point is very important, and essentially serves as a reminder to those responsible in understanding and fully embrac­ing their SSAC role as the technical interface to the IAEA.

In the case of an existing or planned nuclear facility, the SSAC will typi­cally consult with the operator(s) for the preparation of a design informa­tion package that is to be submitted to the IAEA. The design information, in the form of a Design Information Questionnaire (DIQ) for each existing and planned nuclear facility, is used by the IAEA, together with the infor­mation provided in the State’s declaration of the initial inventory of nuclear material, to facilitate the development of the safeguards approach at the State level, including the safeguards measures to be implemented at the respective nuclear facility. Where applicable, the facility design information is also used in (1) development of the Facility Attachment, (2) technical discussions between the IAEA, the SSAC and the facility operator regard­ing the potential installation and service of IAEA containment and surveil­lance (C/S) systems, and (3) the IAEA’s ongoing assessment concerning the identification of indicators of misuse of declared facilities and/or diversion of declared nuclear material from peaceful activities.

The application of C/S systems is complementary to the accounting meas­ures implemented in accordance with the State’s safeguards agreement. As

C/S devices make use of the local design features of the facility, equipment or item (e. g., nuclear material in a storage container or vault), their applica­tion is dependent on a number of factors. Such factors include defining the objective of applying such safeguards measures (e. g., whether it is an indica­tor of possible diversion of nuclear material, an indicator of possible misuse of sensitive equipment or process, or an indicator of possible tampering with IAEA safeguards equipment). Other factors include, but are not limited to, the type and form of nuclear material (to the extent applicable), design information on the containment equipment or facility, and alterna­tive safeguards measures to meet the same objective. As a practical matter, C/S systems are typically utilized in situations where they offer improved safeguards efficiencies or effectiveness, contribute to improvements in personnel safety, health and radiation protection, or are attached to IAEA equipment and other sensitive items (e. g., a sealable pouch contain­ing facility design information) to provide an indication of possible tampering.

For example, we hypothetically consider a large number of containers of nuclear material containing low-enriched uranium oxide powder in a sepa­rate storage area of a facility, where they are to be stored for many years before final disposition. The first time a physical inventory verification is conducted at the facility, the time-consuming task of performing detailed measurements and assays of the nuclear material in the containers will be conducted. During subsequent physical inventory verifications, some of the inspection activities might be reduced or eliminated by the application of an appropriate IAEA C/S measure(s). In the example provided, installation and use of the containment (or surveillance) system is based in part on the cost-effectiveness of the approach. When considering the application of such measures, the IAEA will consult the State in advance of any installa­tion, and they will jointly decide on the merits of any increased efficiencies to be achieved.

If an AP is also in force, normally the State could expect that the first time a complementary access is requested is after the State’s initial AP declarations are received and reviewed by the IAEA. In practice, after the initial AP declarations are submitted, AP update declarations are routinely sent by the State and the majority of complementary accesses conducted are to assure the absence of undeclared nuclear material and activities at the selected location(s). From time to time, there may be ‘questions’ or ‘inconsistencies’ that arise. Experience shows that when the responsible national authority (e. g., SSAC if so designated) consults early and works closely with the IAEA, especially to resolve the questions or inconsistencies in a timely manner, then assurances that a State’s nuclear programme is entirely for peaceful purposes can be strengthened. In this regard, the State’s non-proliferation objectives are being achieved.

In time, the SSAC personnel could expect to include the following func­tional activities in their routine (i. e., day-to-day) safeguards-related activities:

• Periodic conduct of physical inventory takings of safeguarded nuclear material

• Provision of accounting reports and operating records to IAEA in accordance with the Safeguards Agreement and the relevant Subsidiary Arrangements

• Provision of IAEA inspector and technician access to relevant locations and strategic points

• Provision of support (e. g., availability of crane operator, refuelling bridge) during the conduct of on-site safeguards activities (e. g. inspec­tions, C/S installation and maintenance)

• Provision of information and close consultation with the IAEA as appropriate to resolving inconsistencies or open issues

• Conduct of follow-up actions associated with resolution of discrepancies and open anomalies

• Training to maintain or enhance technical skills and abilities of the SSAC and operator personnel

• Development and/or revision of organizational practices, standards, policies and procedures relevant to safeguards implementation

• Consultation in the drafting and updating of Subsidiary Arrangements

• Purchase and maintenance of SSAC-owned safeguards equipment.

With time and experience, the SSAC role becomes more familiar to the personnel involved, especially during the conduct of on-site safeguards activities (e. g., inspections, complementary accesses, design information verification visits).

As described in Section 14.3, a wide variety of radioactive waste is gener­ated during the operation and maintenance of a nuclear power plant and during the final decommissioning and dismantling of the reactor. They are generally distinguished as wet and solid waste. In addition also gaseous waste is generated. These wastes are released to the atmosphere after appropriate filtration and the filters containing the important radioactivity can be handled as solid waste.

The purpose of the treatment and conditioning is to produce a waste package that is suitable for the subsequent waste management steps, i. e. storage, transport and disposal (Fig.14.12). Another purpose is to reduce the volume as is much as is economically justified.

Liquid waste, i. e. contaminated water, is treated by chemical precipita­tion, ion exchange, mechanical filtering and/or evaporation depending on the concentration of radioactivity in the water and the cleanliness of the water, as well as the further use for the water. The products from these treatment processes are wet sludge (solid content <15%), spent ion exchange resins, and filter cartridges. The sludge and ion exchange resins are normally then conditioned to form a solid body (solidification) directly in a package suitable for handling and disposal, while the filter cartridges can be handled as solid waste.

The methods most commonly used for solidification of wet wastes are cementation, bitumination, polymerization and vitrification. In the cemen­tation process, which is the most widely used method, the waste is mixed with cement to form a concrete that is poured directly into the waste package. Care must be taken that the chemical composition of the waste is compatible with the cementation process. The process is fairly straightfor-

ward and is widely used in most nuclear power plants. A drawback is that it normally leads to a volume increase. In the bitumination process wet wastes are mixed with hot bitumen and the remaining water is driven off, thus providing a volume reduction. The bitumen/waste mixture is then filled in the final waste package, normally a 220-litre drum. Bitumination is used at some nuclear power plants and also some reprocessing facilities. More recently also polymerization and vitrification technologies have been devel­oped for wet LLW and ILW. In the polymerization process the waste is mixed with a polymer that uses the excess water for polymerization. In the vitrification process the waste is heated together with glass-forming com­ponents to create a radioactive glass. Vitrification normally requires that the wet wastes are pre-dried. The different processes considered for condi­tioning of wet wastes have different advantages and disadvantages. The choice of process will depend on many factors such as the volumes to be treated, the activity concentration, the chemical composition, the require­ments from the disposal facility and the end costs.

Solid waste has a wide variation in physical form and activity content and the chemical form of the activity. Metal waste is normally decontaminated with mild acids such that the material can be reused. When a material is finally declared as waste it is then separated into combustible, compactable or non-compactable waste. Combustible waste can be incinerated and the ashes taken care of as wet or solid waste and the filters as solid waste. An incineration facility for radioactive material is, however, an expensive instal­lation and will normally require a substantial volume of waste to be inciner­ated. Most of the incinerators installed are therefore central for a country, e. g. in France and Sweden. For compactable waste different types of com­pactors are used, ranging from simple drum compactors, where the waste is compacted directly in the waste package drum, to high pressure (>1000 Mg) supercompactors. In the supercompactors standard 220-litre drums with waste are compacted to form thin ‘slices’ that can then be pack­aged in a drum for subsequent handling. To stabilize the compacted waste or non-compactable waste in the final waste package, concrete is normally poured into the package to provide a solid monolith.

An important part of the waste treatment and conditioning processes is waste characterization. It has to be ensured that the waste form is suitable for the next step, e. g. has the suitable chemical form and/or activity concen­tration. It is particularly important that the conditioned waste package will fulfil the requirement, i. e. the waste acceptance criteria, for transport and disposal.

In most cases each nuclear power plant is equipped with the appropriate facilities for waste handling, treatment, conditioning and storage. In some countries centralized facilities, e. g. for incineration, have been built. In other countries mobile treatment and conditioning facilities have been intro­duced, that can serve several nuclear power plants.

Whatever the differences measured by polls in different countries (notably in the EU Eurobarometers), there are several data which are commonly observed everywhere: [101]

16.1 Responses to the question ‘What do you expect to be the top three energy sources in 30 years?’ (cf. Eurobarometer on Energy Technologies,

of people for nuclear energy, other people against nuclear energy, and an important proportion that are hesitant or without a clear opinion. This group of ‘undecided’ people is an important target for government information on nuclear energy.

• There are some correlations between socio-demographic characteristics (gender, age, education and economic levels), political opinions and nuclear acceptance. Generally, men are more in favour of nuclear power than women, well-educated people are more in favour of nuclear power than the less well educated, and right-oriented people are more in favour of nuclear power than those who are left-leaning.

• People claim to have more trust in non-governmental organizations (NGOs) and scientists than in political leaders, government and the media to give them information on nuclear power.

• In fact, the public is very much influenced by mass media and by political leaders. There is a vicious circle between the perception by political leaders that nuclear power is not a well-accepted choice by citizens, and that therefore there is some political risk attached to supporting it, and the citizens’ perception that there is some reluctance for political leaders to support nuclear power.

• A guarantee of low energy prices for consumers is, everywhere, the main expectation of a government’s energy policy. Nevertheless, security of supply, protection of the environment and of human health are also important expectations (see Fig. 16.1).

• Last but not least, public opinion on nuclear power can evolve: a major accident like Chernobyl can have a great impact on nuclear acceptance everywhere in the world; indeed, after Chernobyl, some countries decided to phase out their nuclear programmes, sometimes via a referendum (e. g. Italy). Following the Fukushima accident, German Chancellor Angela Merkel decided to shut down the older nuclear plants in Germany. In this regard, safety is a shared responsibility for all nuclear operators and all nuclear countries. The Fukushima accident will have consequences for nuclear development everywhere, and particu­larly in Western countries where the nuclear option is more controver­sial. On the other hand, since the 2000s, there appears to have been more and more acceptance of nuclear power, due to a combination of several factors: progressive awareness of climate change as a major issue, the influence of nuclear development in Asia, signs of a ‘nuclear revival’ in the EU and USA, the instability of oil and gas prices, geopolitical ten­sions between suppliers and consumers, the scarcity of raw materials, etc. Making a nuclear choice could be seen as a factor of stability in this context.

A. ALONSO, Universidad Politecnica de Madrid, Spain

Abstract: This chapter describes the technical requirements to be considered in the selection of a site for a nuclear power plant. The design and operation of the nuclear power plant depend on the site characteristics; the site-derived risks have to be considered in the plant design basis, and the site itself has to bear the risks and detriments coming from the plant. The design has to cope with expected extreme natural phenomena and combinations of those, as well as human — induced events, without impairing the operational safety of the plant. The site has to provide needed requirements such as rejected and decay heat sinks, availability of electrical power supplies, good communications and effective emergency management, including the evacuation of nearby residents.

Key words: site evaluation, site seismicity, extreme meteorology, ultimate heat sink, population density, site parameters, human-induced events.

18.1 Introduction

Site selection for nuclear power plants (NPP) requires the analysis of a set of diverse parameters which are divided into the following five groups: [102] materials. These conventional factors, although relevant, for NPP site selec­tion are not developed further. Some of these elements are considered in the chapter on site and supporting facilities in the IAEA ‘Milestones’ docu­ment (IAEA, 2007a).

Site characteristics which may impact plant safety are essential in the safe design of the NPP. Extreme meteorological conditions, such as hurricanes, tornadoes and heavy rain, hail or snow falls and lightning may produce floods and impair plant accessibility; floods can also be produced by large tides in combination with heavy rain in estuarine waters or by rupture of up-river dams; earthquakes and the ensuing tsunamis may produce damage to buildings and external facilities as well as violent floods in coastal sites. All these events require buildings, water intake structures, external water tanks, electrical grids and electrical transformers to be protected by design. These aspects will be considered in depth.

Man-made external activities offer risks to the safety of the plant. Large explosions and toxic releases in the vicinity of the plant produced, for example, in the transportation of liquefied natural gas or other explosives or gaseous toxic substances by road, rail or waterways have to be avoided and the consequences to the plant mitigated by design. Proximity to har­bours, airports and military installations should also be avoided as they represent a risk to the safety of the NPP. These hazards are also considered in detail.

Extreme natural events, such as the impact of large meteorites, massive volcanic activity or pandemics are not generally considered. There should also be protection against sabotage, but this matter is not considered in this chapter, as it is not site dependent and it is generally prevented by security measures.

The NPP creates risks and detriments to the surrounding population and the environment that have to be previously analysed. The impact of radioac­tive releases during normal operation requires meteorological and hydro­logical dispersion parameters. The transport of contaminants along the terrestrial and aquatic food chain pathways needs to be considered. Demographic parameters are needed to assess the potential doses that dif­ferent population groups may receive and the performance of epidemio­logical studies to determine any potential radiation effects. These risks and detriments are considered.

A major consideration is the protection of the population in case of accidents with radiological effects. The site conditions should facilitate the evacuation of the affected population, the establishment of decontamina­tion and receiving centres and the medical treatment of potential exposures. Population distribution, communication and evacuation routes are relevant aspects of site evaluation. The site requirements for an effective nuclear emergency plan are emphasized.

Most countries have regulated that any major industry or activity has to analyse the environmental impact it may produce. A major environmental impact of the NPP is due to the rejection of heat required by the second law of thermodynamics. The thermal efficiency of NPPs is about one-third, therefore two-thirds of the heat generated has to be rejected to an ultimate heat sink, which could be the atmosphere through different types of cooling towers, or large water bodies such as big rivers, natural or artificial lakes, or the sea in coastal sites. Cooling towers release large amounts of steam to the atmosphere with minor meteorological impacts on the surroundings, and heat rejected to water bodies, causing even small temperature increases, may produce substantial variations in the life and development of aquatic organisms. NPPs also produce chemical impacts, mainly in water bodies; production and releases of conventional waste; an increase in light and heavy traffic, mainly during construction; and a substantial aesthetic impact, mainly if using large cooling towers. These impacts are not considered in detail in this chapter. Such aspects are described in Chapter 8.

All the effects named above require specific studies and consideration. In this chapter safety parameters will receive more attention. The basic scientific basis will be exposed and references to applicable International Atomic Energy Agency (IAEA) standards will be introduced to serve as additional information.

The scope of supply for spare parts, special tools and consumable materials shall be specified in the SS document. The supplier shall be requested to provide all spare parts, special tools and consumables required for the installation, testing, commissioning and operation of the systems and equipment included in his scope of supply until final plant takeover by the owner. The bidder shall provide with his bid a list of recommended spare parts and special tools for the period extending up to takeover. Should additional spare parts or special tools that were not included in this list be required, for any reason, before plant takeover, they shall be furnished by the supplier at no extra cost.

The supplier shall also be requested to include in his bid another list of spare parts and special tools (indicating unit prices, quantity and delivery times) that will reasonably be necessary to ensure a number of years of normal plant operation (e. g. 3, 5 or 10 years). The owner may decide to request the submittal of separate lists, one for each specific period, to facili­tate the evaluation and decision-making process.

The bidder shall also guarantee the availability and delivery of the spare parts for a reasonable number of years; in the event of a particular spare part or special tool becoming unavailable before the end of this period (e. g. production has been discontinued or the manufacturer has gone out of business), the owner should have the right to use all drawings and specifica­tions relating to this item to procure it on the market.