The educational system (universities and vocational schools) will support the baseline of highly qualified professionals in the different specialities required by the nuclear programme. The nuclear training organizations (nuclear institutes and training centres) will enhance the specific nuclear competencies of the graduates from the educational system, giving them a more practical approach to their future duties.

The training organization should be established as soon as possible, since it is the pipeline to generate nuclear knowledge for the new staff. Training instructors should therefore be one of the first groups of people to be hired in the human resources planning. Senior instructors from existing training centres or external support (from the main supplier or specialized compa­nies) will be required to train new instructors.

The availability of a plant-referenced simulator well in advance of fuel loading not only provides a unique tool for training control room personnel, but also is very useful for the development and validation of operating procedures, commissioning tests, and training of other plant personnel, as well as for a variety of activities including engineering, design modifications, configuration management and licensing. Appendix 4 discusses training in these plant-referenced simulators.

Senior instructors can cooperate in the specification of the simulator and the writing of the acceptance test procedures, but additional hardware and software engineering will be needed to develop the simulator model and panels.

The ENEN association, currently comprising 41 members, plays a major role in shaping Europe’s education system. ENEN facilitates exchanges and cooperation within academic institutions and strengthens their interactions with research centres. It delivers the certificate of European Master of Science in Nuclear Engineering (EMSNE). It further develops, promotes and supports ENEN exchange courses in nuclear disciplines including reactor safety, waste management and radioprotection. It facilitates and coordinates the participation of universities in European research projects.

To the benefit of the end users, ENEN preserves nuclear knowledge and improves access to expertise by developing and establishing databases, websites and distance learning tools. It has a role as an interface between academia and industry, to define, disseminate and support interesting projects and research topics for internships, masters’ theses and PhDs. by developing a framework for mutual recognition of professional training, licensing and professional recruitment throughout the European Union, ENEN is creating a nuclear ‘European Education and Training Area’.

Operation of a NPP will result in some radiation exposure to plant person­nel as also to the public in the area in the vicinity of the NPP due to release of liquid and gaseous radioactive effluents from the plant. These exposures have to be maintained within the limits prescribed by the regulatory body and as low as reasonably achievable. This is done through design provisions whereby all radiation sources in the NPP are properly shielded and con­tained and by following appropriate procedures for carrying out O&M

activities. For limiting the radiation exposure of the members of the public, adequate checks are maintained for controlling the radioactive effluents from the NPP to the environment and developing appropriate models for assessing the exposure of the public from such effluents by way of direct exposure, as also by inhalation and ingestion through the terrestrial, aquatic and air routes. The design provisions and specified procedures shall take into account exposures during normal operation as also during off-normal situations including accident conditions. Towards this aim a robust radiation protection programme must be in place well before the start of NPP operation.

The radiation protection programme comprises monitoring the radiation exposure of all personnel inside the operating island and at other places such as in the waste disposal facility or in the away-from-reactor spent fuel storage area which have a potential for causing radiation exposure. Monitoring of external exposure is done by measuring the radiation dose received by radiation exposure monitoring devices such as thermo­luminescent detectors or direct reading dosimeters that have to be worn by all radiation workers while in the plant. Internal exposures are moni­tored through bioassay samples and whole body counting of the workers. Radiation dose to the public is assessed by measuring radioactivity levels in air, water and soil samples around the plant and in food items including milk and milk products consumed by the public around the NPP and by estimating the dose using validated computational models.

In addition to monitoring of personnel exposures, radiation levels in various areas of the NPP and radioactivity levels in the fluids in the reactor systems and in the air in various plant areas are regularly checked. The water and air samples are also subjected to gamma spectrometry to identify the presence and concentration of various radionuclides to obtain informa­tion on the source of radioactivity in these fluids. All plant areas are regu­larly checked for radioactive contamination and various measures are taken, including the use of personnel protective equipment by workers and barricading of areas to prevent contamination of workers or spread of contamination. To limit the radiation exposure of workers during mainte­nance work or special operations like refuelling, their time of exposure is limited and temporary radiation shields are used to reduce the radiation level at the work spot. At times the work is performed using remote han­dling devices to bring down the exposure by increasing the distance between the workers and the radiation source. Fresh air masks are used to prevent internal exposure from intake of airborne radioactivity.

For effective implementation of the radiation protection programme a dedicated group of health physicists is required with a high level of com­petence in radiation monitoring, assessment of radioactivity levels in various matrices, control of radiation exposure of personnel and prevention of spread of radioactive contamination. Appropriate laboratory facilities are also required to be set up for carrying out all necessary measurements and analysis of samples. A high fraction of the total radiation exposure of plant workers takes place during refuelling, maintenance and in-service inspec­tion work performed during planned outages of the NPP. The health physics personnel play a very important role in minimizing these exposures by advising plant personnel on the appropriate measures that need to be taken. For this reason, in many countries, the key health physics staff are formally authorized by the regulatory body after extensive training.

At times unplanned exposure of personnel may take place or personnel may get over-exposed due to loss of shielding, failure to follow prescribed procedures, inadequacy in the procedures or improper use of protective equipment. All such cases must be analysed in detail to identify the direct as well as the root causes to decide on the appropriate modifications in hardware and procedures to prevent recurrence. A high level of technical competence in the health physics group and radiation safety awareness in the workers is required for proper implementation of the radiation protec­tion programme at the NPP with the aim of keeping all radiation exposures within the prescribed limits and also as low as practicable.

One of the key objectives in the design of evolutionary reactors has been to reduce the total ‘overnight’ capital cost1 of a new nuclear power plant. To this extent, most designs include a significant reduction in the total number of structures, systems and components as well as a simplification of plant systems and components by using fewer and larger components, and by combining or eliminating functions or systems. The development of stan­dardized designs that need to be validated and licensed only once also offers significant cost savings by spreading fixed costs over several units of the same standard design (IAEA, 1999b). Because first-of-a-kind reactor designs or plant components require detailed safety cases and licensing processes that result in major expenditures before any revenue is realized, standardization of a design is therefore a vitally important component of capital cost reduction. Many evolutionary designs have been developed based on ‘user requirements’, most notably by the Electric Power Research Institute (EPRI, 1995, 1999) and in the European Utilities Requirements (EUR, 2001), that is, the lessons learned from the operation of the existing [4]

fleet of nuclear power plants. The compilation of these ‘user requirements’ has had a tremendous impact in achieving international consensus regard­ing commonly acceptable safety requirements and performance expecta­tions that would facilitate development of standardized designs which can be built in many countries without requiring significant redesign efforts.

Shortening the duration of the plant construction is important because of the interest and financing charges that are accrued during this period without countervailing revenue. However, it is important to remember that the objective is to reduce the overall plant cost, which means an optimiza­tion of construction schedule, construction costs and construction quality. It would not be meaningful to reduce the overall schedule period if that would result in an increase of the overall spending or incur later mainte­nance costs in a way that negates the savings in interest during construction. Recent nuclear construction projects have achieved optimum construction duration, cost and quality by streamlining the construction methods, using advanced construction technologies (all-weather construction, slip forming, open-top construction, modularization and prefabrication, advanced con­crete mixing and pouring, automatic welding) and effective project manage­ment practices (IAEA, 2002) Figures 9.1 and 9.2 illustrate two recent examples of advanced construction projects. The use of effective pro­curement and contracting, as well as the close coordination with all relevant regulatory authorities, are also important contributors to this optimization.

One of the innovations incorporated in the design of evolutionary nuclear reactors is the use of modularization and factory prefabrication for both structural and system modules. Modules are fabricated in a controlled

environment in a factory or in a workshop on the plant site, which normally improves their quality as compared to the traditional on-site stick build technique. Multiple modules can be fabricated in factories or workshops, while the civil work is progressing on the site in preparation to receive the modules. On the site, only sequential assembly of the modularized assem­blies is required. This reduces on-site congestion, improves accessibility for personnel and materials, and can improve the construction schedule. It can also significantly reduce the manpower needs for the construction site work.

Another way to reduce the overall capital costs involves taking advantage of economies of scale and thus designing larger reactors where the capital costs can be amortized faster due to the larger electricity production. On the other hand, for some market conditions, increasing plant size to capture economies of scale may result in plants too large for many national grids or to meet the incremental demand. This has resulted in recent times in a parallel trend that encourages the development of small or medium-sized reactors (SMR) that are more affordable and can be built in a phased manner up to the total desired power based on the electricity demand or the financial means of the owner. These smaller designs may also be ideal for newcomer countries with small electric grids and/or limited financial resources. SMRs have the potential to capture economies of series produc­tion instead of economies of scale, if several units are constructed.

Most evolutionary designs also include design features that allow for plant lifetimes of 60 years and longer, thus spreading the capital investment over a longer plant operation life.

Evolutionary reactor designs have also been designed to achieve lower operating costs, such as with the optimization of the fuel cycle that brings savings in the form of increased plant availability, more effective use of fissionable resources, and minimization of waste and used fuel quantities and management costs. These designs also strive to obtain higher thermal efficiencies by using high-performance advanced turbines and sophisticated thermodynamic cycles, as well as expanded non-electrical applications. At the same time, since these new designs are expected to operate under higher demands, they employ improved corrosion-resistant materials and take advantage of major advances in fracture mechanics and non-destructive testing and inspection.

Evolutionary reactor designs employ several means to obtain perform­ance improvement, such as the use of highly reliable ‘smart’ components (instrumented and monitored) able to detect incipient failures and to monitor their own performance. The effective application of smart compo­nents allows reducing the dependence on costly redundancy and diversity practices and permits the optimization of maintenance and replacement schedules. Most evolutionary designs also incorporate in-service testing and maintenance, thus further improving capacity factors.

The design, operation and maintenance of evolutionary reactors show an increased reliance on probabilistic risk assessment methods and databases that allow designers and operators to focus their efforts on the systems and components with higher risk of failure. The use of advanced computer modeling and simulation tools have fostered significant improvements in plant design and layout, plant arrangement and system accessibility, and in design features that facilitate decommissioning. In fact, current ‘multidi­mensional’ project management software is able to manage and coordinate all aspects of the life of a plant from the design to the operation and main­tenance, including configuration control and other key construction proc­esses such as procurement, manufacture, inventory, spare parts, costs and schedules. Another area that has had significant impact in the elimination of over-design and excessive safety margins has been the improvement of the technology base (i. e. improved understanding of thermo-hydraulic phe­nomena, more accurate databases of thermo-hydraulic relationships and thermo-physical properties, better neutronic and thermo-hydraulic codes, and further code validation). The only margins still accounted for in the design are simply associated with the limitations of calculation methodolo­gies and uncertain data.

One of the best-known improvements incorporated into many evolution­ary reactors is the use of passive safety systems that utilize gravity, natural convection and temperature and pressure differentials, enabling these systems to function without electrical power supply and/or actuation by powered instrumentation and control systems.

Advanced nuclear reactors have also paid increased attention to the effect of internal and external hazards in the design, in particular the seismic design and the qualification of buildings. At the same time, many of these designs have placed increased emphasis on the prevention and mitigation of severe accidents.

Last, but not least, advanced designs have taken advantage of the rapid progress in the field of control and instrumentation, in particular, with the introduction of microprocessors into the reactor protection system and with the use of digital instrumentation and control (I&C). An important devel­opment in these designs is the increased emphasis on the human-machine interface, including improved control room design and plant design for ease of maintenance.

From the earliest beginning of the nuclear era, governments have estab­lished, and then have relied on regulatory organizations to audit the per­formance of organizations of all sorts related to use of ionizing radiation — isotope users, miners, researchers, health professionals, and power plant operators. These regulatory organizations issue licences to operate within carefully defined rules and regulations. They usually perform detailed audit­ing and enforcement duties, especially through staff members at the loca­tion of major facilities such as power plants.

The positive value of audit staff to the plant owner/operator arises from their emphasis on safety. This emphasis helps to provide balance to the strong motivation of plant senior management, who may at times consider production as their first and overriding priority. This need for balance pro­vides the most fundamental infrastructure requirement that justifies the purchase of a nuclear plant; that is, the need for a competent review of plant safety performance before the plant is purchased, to ensure that later per­formance will meet the exacting standards required by the safety regulatory agency.

The International Nuclear Safety Advisory Group has prepared a draft proposal for an integrated process, as described in INSAG-25 (2010). This document aims at the most difficult of all safety-related actions; that is, the decision process surrounding the question of what is a sufficient level of safety. As noted in the INSAG document, the process must be flexible to adapt to the myriad of different situations under which these decisions must be made. For example, the decision process to be applied during the stage of conceptual design of a plant can be much broader and more thoroughly researched than can the process that must be applied when (purely for example) a redundant pump fails for some reason during operation and the appropriate subsequent action must be decided. The difference lies mainly in the time available for decision and action — much shorter in the second case.

The general roles of the major stakeholders in the safety management system were discussed in Section 10.2.4. Specific relationships during plant operation are much more complex, but at a higher level always consist of an operating organization overseen and audited by experienced and independent technical staff on behalf of the licensing authority. Fig. 10.8

illustrates a somewhat more detailed map of one possible set of processes involved in arriving at a safety-related decision.

To alleviate the enormous expenditure of resources involved in a step — by-step operation of the process involved in Fig. 10.8, it is usual to develop a set of symptom-based operating procedures for use by the individuals and groups who actually operate the plant controls. Properly developed and tested, these procedures can dramatically shorten the decision and action time required. Procedures must be developed through a comprehensive and interactive process such as that described in INSAG-25 (2010). They must also be periodically updated based on operating experience. The same rule must hold for equipment or design modifications that may be required periodically in a mature operating plant. Finally, if significant changes occur in the external environment of the plant (for example, a newly discovered threat) then a review may result in changes to operating procedures or equipment in order to deal with the new situation.

It should moreover be noted that effects can occur in human cells exposed to relatively high levels of radiation. These effects can be detected through specialized bioassay specimens, such as some haematological and cytogenic sampling. They may be used as biological indicators of the exposure and can help to identify and even quantify high individual exposures to radia­tion, such as those occurring in accidents. However, the presence of biologi­cal indicators of exposure does not necessarily imply that the individual had experienced or would experience health effects that could be attributed to radiation.

A nuclear emergency starts when the plant monitors indicate that some operational systems do not operate properly and the situation cannot be controlled by the corresponding safety systems adequately. Upon failure detection, the plant operator evaluates the impact of the incident on the plant and identifies the affected systems and the availability of alternative systems to control the situation. Simultaneously, the plant operator inves­tigates whether the incident could lead to the escape of radioactive material within the plant or to the environment. Based on the results of its prelimi­nary evaluation, the operator initiates the mitigation actions, decides the level of the on-site emergency plan to be activated, and notifies the situation to the emergency coordinator who is responsible for off-site emergency plan activation.

Transition from normal operation to an emergency situation is a critical step that needs to be clearly established in emergency plans; for this reason, the operators are specifically trained in the use of procedures to identify abnormal situations within the plant, activate on-site emergency plans, and implement the emergency procedures to handle the situation. Similarly, activation of the off-site emergency plans requires specific training of the authorities in charge of response and intervention. The on-site/off-site inter­face also needs careful implementation to avoid any delay or disturbance in taking the necessary countermeasures.

Spent nuclear fuel is removed from the reactor when it can no longer con­tribute to the fission energy process, typically after three to seven years use. The fuel, however, still contains components, uranium and plutonium, that could be reused and recycled as fuel material. As for most waste in our society, e. g. paper and glass, there is, however, an economic issue involved in the decision to recycle or not. Although the remaining uranium and plutonium can be recycled as mixed oxide fuel (MOX) in present-day light water or heavy water reactors, real benefit from recycling will only be achieved if the fuel is recycled in fast spectrum reactors, so called fourth- generation reactors, which are being developed now. There are thus two options for spent fuel management:

• regard the fuel as a waste and dispose of it in a deep geological reposi­tory after a period (>30 years) of interim storage for sufficient cooling, or

• reprocess the fuel to separate out the components that can be recycled as fuel material after a period (~10 years or less) of interim storage. The remaining waste products (HLW and ILW) will still need geological disposal.

Some countries, e. g. Canada, Finland, Germany and Sweden,[82] have chosen the direct disposal route, while other countries, e. g. France, India and Japan, have chosen the recycling route. Most countries, however, have still not decided which option to choose. As spent fuel storage for decades is a straightforward and proven technology, there is no urgent technical need to make the choice. Prolonged storage will provide time to consider the progress in fast spectrum reactors with effective recycling, and provide a better basis for making the choice. Storage times of 100 years and more are now considered in some countries. As both options will in the end require a deep geological disposal facility, it will be important to work towards the development of such a facility, not least from a political acceptability point of view.

The views on reprocessing or direct disposal have changed over time. Some countries, e. g. Germany and Sweden that in the 1980s sent fuel for reprocessing, changed their policy in the 1980s to storage and subsequent disposal. Also in the USA the position has changed over the years. Reprocessing was the main option early on and some civilian reprocessing plants were built. Since the early 1980s the main option has been direct disposal, and investigations for developing a disposal facility at Yucca Mountain in Nevada were conducted up to the point that a licence applica­tion was submitted to the US Nuclear Regulatory Commission in 2008. This application was later recalled in 2010. In parallel, studies were conducted on reprocessing and recycling in fast reactors. In 2009 a Blue Ribbon Committee was set up to advise the Administration on the way forward. The result of the Commission is due in 2012.

The steps for spent fuel management include interim storage, reprocess­ing and subsequent recycling of fuel material and conditioning of the remaining waste for disposal, or encapsulation of the fuel for disposal, and final disposal. As the facilities involved are normally located at different locations, transport will also be needed. Interim storage can be made in pools in the reactor facility or in separate storage facilities, containing either water pools or dry casks or vaults (Fig. 14.1). Given the trend towards longer storage times, there is also a trend towards using dry storage systems that can be built in modules as the needs arise and that will require less active operation. There is also a trend towards primarily expanding the storage capacity at the reactor sites to avoid extra transport.

Reprocessing facilities and facilities for producing MOX fuel exist today in only a few countries — France, India, Japan, Russia and the United Kingdom. These facilities need to be quite large and involve technology that is sensitive from a nuclear proliferation point of view. It can thus not be expected that they will be built in many countries. The existing facilities have served nuclear utilities in several more countries. In most cases the wastes from reprocessing, HLW, ILW and LLW, have been returned to the country of origin for storage and disposal.

So far no country has started disposal of spent fuel or high-level or intermediate-level waste in deep geological repositories. Development work is underway in several countries and good progress can be seen in Finland, France and Sweden, countries that expect to start disposal in the period 2020-25. Although the technology for disposal is fairly straightfor­ward and simple, the safety assessment poses important challenges, as the time periods to be considered are very long (from thousands to hundreds of thousands of years). Another important challenge is the public and politi­cal acceptance of disposal. Important setbacks have been experienced in many countries, which has delayed the disposal projects and led to impor­tant changes in the siting process. Experience has shown that the time needed for developing a deep geological disposal facility, including the time needed for scientific studies and siting, is at least 40 years.

More technical details of the different steps for spent fuel management are given in Section 14.4.

Uranium prices have been volatile over the past 30 years. The end of the Cold War curtailed the need for large stockpiles of military fissile materials, and the bleak prospect for civilian nuclear power during the 1990s enticed utilities to reduce their uranium inventories. So-called secondary uranium sources (reactor fuel derived from warheads, military and commercial inventories, re-enrichment of depleted uranium tails, as well as enriching at lower tail assays, reprocessed uranium and mixed oxide fuel) became increasingly available, e. g. through the 1993 agreement between the United States and the Russian Federation to convert highly enriched uranium (HEU) from nuclear warheads into low-enriched uranium for reactor fuel
(also known as the Megatonnes to Megawatt programme). Low-cost sec­ondary sources penetrating the uranium market and a general perception during the 1990s that nuclear power is a technology inevitably in decline suppressed uranium prices and mine production. Ever since 1990 annual fresh uranium production has fallen short of annual reactor requirements. Historically, low spot market prices threatened economic survival of many mines. Without clear long-term demand signals from the marketplace, the uranium industry has been reluctant to invest in new mine capacities or to pursue large-scale uranium exploration. Meanwhile, global production had progressively declined to less than 60% of reactor requirements. Clearly, uranium prices no longer reflected longer-term production capacities (Rogner, 2007).

Shortly after prices hit the historical low, a series of events uncovered the long-ignored demand/supply imbalance and caused prices to rise. On the demand side, since 1990 rising plant factors of the world’s nuclear fleet added incrementally to annual reactor fuel requirements the equivalent of more than 30 GWe. A series of licence renewals for existing reactors that began around the turn of the century sent plant operators out to secure fuel for another 20 years or so. Another change was the growth of nuclear power in the developing economies of China and India, countries that had either not participated in the market to a great extent or not participated at all. While demand was picking up momentum, supply from mine output con­tinued to be underprovided. In fact, in the face of rising demand several technical mishaps at major production centres reduced global mine output and prices began to rise. Moreover, the longer-term availability of second­ary sources from military arsenals is politically determined and thus uncer­tain and the bulk of future uranium supply had to be provided by additional mine output, i. e., investment in exploration and development of new mines and mills. Given lead times of 5-10 years for new mining capacity to come on-line, in the short run production cannot increase rapidly despite rising demand. Beginning in 2004, the general demand-driven price acceleration of fossil fuels, materials and commodities further aggravated uranium prices and, by 2007, spot prices had exploded almost 20-fold.

As for almost all commodities, uranium market conditions abruptly changed with the onset of the financial and economic crises in 2008. At the close of 2009 spot prices were about 35% below their mid-2007 peak of $350/kg U. Yet compared with other commodities, the uranium market weathered the storm fairly well. Uranium is generally better protected against aberrations than other markets. For one, short-run reactor uranium requirements are relatively stable as existing nuclear power plants are usually the lowest-cost generators on the grid and global annual reactor requirements of uranium of approximately 67,000 U remained unchanged. For another, most uranium (about 85%) is supplied under long-term con­tracts, where the pricing is shielded from sudden market fluctuations. New contracts or contract renewals then tend to also reflect the current spot price situation among other demand and supply factors. Typically, average long-term multiannual contract prices have been about half the going spot market price.

What brought down spot prices — in addition to the precipitous fall of energy, material and commodity prices — were those hedge funds and investors who since 2004 have traded in uranium and who, to a certain extent, added fuel to the 2004-08 spot price rally and, as a result of the financial crisis, were forced to sell their uranium positions due to cash requirements.

The longer-run price outlook, however, depends on whether or not above-ground investment in exploration and mining capacity will be forth­coming and mobilize the below-ground uranium resources. While global uranium resources are plentiful (NEA, 2010; Rogner, 2010) and the recent prices have stimulated both exploration and investment in new mining capacity, it remains to be seen if these are sufficient to meet additional demand caused by the expected nuclear renaissance but also to compensate for the likely decline in availability of secondary sources. Therefore, consid­erable uncertainty about future uranium prices remains. In the long run, uranium prices will be capped by the possibility of reprocessing of spent fuel. Except in Japan, no new commercial reprocessing facilities have been built for decades. The existing quasi-commercially operating plants in France and the United Kingdom initially served military purposes and were adapted or rebuilt for spent fuel reprocessing in the 1960s and 1970s under fundamentally different conditions (e. g., exponential growth of nuclear power, perceived limited uranium availability, continued demands for mili­tary purposes) and expectations of future nuclear power development in which plutonium-fuelled fast breeder reactors played a central role. This future did not materialize, but reprocessing continued, often rationalized as an integral part of a nation’s nuclear waste management strategy or as a source for mixed oxide fuel (MOX) production and reuse in standard light water reactors (LWR). In any case, the expensive construction costs were quasi-stranded (sunk costs) and reprocessing services were offered interna­tionally at attractive terms. In short, the economics of reprocessing in the near future hinge upon substantially higher uranium prices (or the equiva­lent of the revival of fast breeder reactor technology). During the last decade several studies attempted to cut through the complexity of reproc­essing with its capital and operating cost depending on a mix of potential credits for recovered fissile materials, different waste volumes, interim storage requirements, high-level waste treatment and final disposal, and to determine break-even points with regard to uranium costs and once-through fuel cycles. For example, Bunn et al. (2003) concluded that ‘at a central reprocessing price of $1000/kg of heavy metal (kgHM), and with other central estimates for the key fuel cycle parameters, reprocessing and recy­cling plutonium in existing light-water reactors (LWRs) will be more expen­sive than direct disposal of spent fuel until the uranium price reaches over $360/kg of uranium metal.’ Likewise, the study The Future of Nuclear Power (Deutch and Moniz, 2003) concluded similarly, and that conclusion was repeated in the authors’ 2009 update (Deutch et al., 2009) which stated that ‘given the assumptions about uranium resource availability and new plant deployment rates, the cost of recycle is unfavorable compared to a once — through cycle, but the cost differential is small relative to the total cost of nuclear power generation’.

The crux of the matter of all things concerning the nuclear fuel cycle is contained in the last part of the conclusion: nuclear fuel cycle costs have been and will continue to be a small cost component in total nuclear gen­erating costs. The actual fuel costs per MWh are a function of the front-end costs, capacity factor and burn-up (number of MWh per unit of mass gener­ated from the fuel) and the overall spent fuel management strategy (once — through or reprocessing and reuse). A very recent study estimated the once-through fuel cycle cost for LWRs at $8.67/MWh or some 10% to 14% of total generating costs (Rothwell, 2010).

The cost components for spent fuel management, disposal and decom­missioning are accumulated in escrow funds (or equivalent schemes) as the plant operates and account for approximately 10% of total O&M costs (or approximately $1/MWh). However, these components can vary widely depending on reactor technology, regulatory requirements and the time frame over which these must be accumulated.

The lifetime fuel requirements (in terms of volume) of nuclear power plants are relatively small (compared with fossil generation) and so are the amounts of spent fuel and waste. But spent fuel is radioactive and must be kept isolated from the environment. Most countries require spent fuel to be stored at the plant site for an interim period until its radioactive inven­tory is greatly reduced and the fuel can eventually be transferred to a permanent repository outside the plant site. If spent fuel is accumulated over many years or the entire plant life, sufficient storage capacity must be provided.