While OC are important for vendors for preparing their cost calculations and bids, it is the sum of OC and IDC that utilities must arrange financing for. The investment decision, however, is usually guided by a comparison of the total estimated generating costs, i. e. OC plus IDC plus estimated future fuel, operating and maintenance costs, of nuclear power to the same sum for alternative electricity generating options.

Four factors determine the IDC of a construction project: (a) OC, (b) the construction period, (c) the distribution of the OC over the construction period, and (d) the return on equity to shareholders and the interest rate, or rates, to be paid for loans (different rates may apply to different plant components or construction stages). IDC adds an extra layer of uncertainty to the final investment costs of a nuclear power plant. While interest rates can usually be fixed before construction begins or, if they are variable, hedged through various financial instruments, the largest uncertainty in IDC arises from possible construction delays. When cost overruns occur, the largest portion is generally due to construction delays. To the extent that regulatory intervention during plant construction causes delays, it will also increase IDC.

Table 15.1 shows that an increase in the construction period from four years to six or 10 years can increase IDC’s share of total investment costs

from 28% to 41% or 75%, assuming OC of $2000/kW(e), a uniform distri­bution of OC over the construction period and a 10% real interest rate. If the interest rate were only 5%, IDC would be 13%, 19% and 32%, respec­tively, of total investment costs.

Although the particulars will vary considerably between jurisdictions, the decision to build a new nuclear plant will invariably involve a consideration of the anticipated environmental impacts, and whether they can be miti­gated, or even tolerated, to a level whereby the benefits of the development will sufficiently outweigh them. This is not a trivial consideration and history has demonstrated the role that environmental considerations can play in shaping development decisions. There are a variety of different stakehold­ers involved that can influence the decision-making process in favour of the environment such as concerned local residents, nongovernmental organisa­tions and the environmental and planning authorities. All of these inter­ested groups have the potential to ensure that the environmental impacts of a proposed development, taking into account the information available, including that generated from environmental assessments, are factored into the decision on whether or not to proceed. These considerations will also have an effect on the resulting site licensing conditions if the authorities ultimately do provide consent for a proposed installation.

In most civil nuclear States, the planning system is employed to manage the process and help ensure that there has been adequate scrutiny of envi­ronmental impacts. Environmental considerations play a pervasive role in the planning debate and there is therefore a need to understand its proc­esses and the key authorities involved. Although there are common features which unite the legal processes of individual States, this is an area where they have retained considerable autonomy. There are, therefore, a number of permutations and no approach to draw from which will be generally applicable.

For example, many of the relevant provisions that govern the nuclear planning regime in the US are contained in Part 51 of the United States Regulatory Commission’s NRC Regulations (10 CFR Part 51). In addition, IAEA documentation such as the Fundamental Safety Principles (IAEA, no. SF-1), Milestones in the Development of a National Infrastructure for Nuclear Power (IAEA, no. NG-G-3.1) and Stakeholder Involvement in Nuclear Issues (IAEA, INSAG-20) are all important starting points from which most civil nuclear States have developed their domestic legal systems. Although there is no common approach, the UK experience serves as an instructive model with respect to land-use planning. The Planning Act 2008 (PA 2008) has introduced significant changes which will alter the content and procedure of the planning process (albeit subject to further change following the election of the coalition government in the UK in May 2010). Added to this is the considerable international interest in the UK market relating to its commitment to a new generation of nuclear power stations. There is significant common ground between the planning system in the UK and other civil nuclear jurisdictions, and a general understanding of its key features will be beneficial to a variety of different stakeholders.

The potential impacts that an operating NPP may bring to the site are related to the atmospheric, surface and ground water dispersion of radioac­tive material affecting the population and the use of land and water in the affected region. Specific requirements and corresponding safety guides follow.

Atmospheric dispersion of radioactive materials

During NPP operation small amounts of radioactive nuclides are released to the atmosphere under strict control. Those nuclides include some noble gases which cannot be retained by any treatment process, as well as some volatile elements and particulate matter which may not be completely retained in the high-efficiency radioactive waste treatment system.

In pressurized water reactors (PWRs) fission and activation gases in the coolant are separated and stored for decay and finally vented to the atmos­phere before refuelling outages; most of these gases have short lives and disappear during the storage period with the exception of krypton-85 (half­life 10.6 years) which becomes the larger contributor of gaseous releases. Iodine-131 (half-life 8.06 days) and hot particles — radioactive particles including fission and activation generated radioactive nuclides — could also be found in the containment atmosphere from coolant leakages. Small amounts of such materials can also be released to the atmosphere after being filtered by activated carbon filters, to retain iodine, and high-efficiency particle air filters. In boiling water reactors (BWRs) radioactive gases gen­erated in the coolant are carried by the steam, separated in the condenser and released to the atmosphere continuously after passing for a few days through a delay system composed of a large activated carbon bed main­tained at low temperature; short-life nuclides decay during transit through the bed with the exception of krypton-85 and xenon-137 (half-life 5.27 days), while most of the iodine nuclides are retained in the activated carbon bed.

The behaviour of the released radioactive nuclides has to be predicted to measure the potential effects of such releases on the health and safety of the affected people and on the environment. Meteorological dispersion parameters have to be measured by dedicated meteorological towers to determine wind speed and direction, air temperature, precipitation, humid­ity and atmospheric stability parameters. With all these data sophisticated dispersion models are developed which also take into account the topogra­phy of the place and the effects that buildings may have on the dispersion of the released materials. These studies are conducted at least one year before starting plant construction and meteorological towers and data gath­ering are maintained during the whole operating life of the NPP.

The availability of meteorological data at the time and during an acci­dental release of radioactive products is essential to emergency manage­ment. In these cases the site dispersion data have to be supplemented with the data and dispersion models of the country’s central meteorological agency.

An IAEA safety guide has been developed to indicate the ways and means to obtain such data and develop the site dispersion models (IAEA, 2002b). The guide describes how to select and display a meteorological data gathering system appropriate to the topography and physical characteristics of the region where the plant is located. The guide also describes methods to develop an ad hoc dispersion models which will also include the con­tamination of soil and the potential resuspension of radioactive aerosols and hot particles, as well as contamination of vegetables and other food products. Such models are essential parts of the theoretical estimation of the potential radiation doses that the affected population may receive from atmospheric radioactive releases by direct exposure to the radioactive cloud and other pathways. The model is also essential in the epidemiological studies generally conducted around nuclear sites.

This section is dedicated to laying out the owner’s requirements for com­munications among project participants. The main topics to be addressed are requirements for written communications, correspondence filing and coding system, correspondence distribution criteria, record keeping, quality assurance requirements for the transmission of quality-related design data, and record of correspondence pending answer.

19.4 Technical data sheets

The technical data sheets (DS) document consists of a set of data sheets summarising the following information in a table:

• The main technical requirements specified in the TR, NF and PI documents

• The main technical data for plant structures, systems and components.

The table format usually presents the information in the following manner: in the left-hand column, the owner briefly sums up the key technical require­ments for which a summary answer is requested from the bidder (to be included in the right-side column, left blank). This table is to be completed by the bidder directly and included in his bid.

It should be noted that data sheets are only a summary of technical features and data presented in an organised and systematic manner, for the purpose of obtaining, in addition to the bids: (a) answers from all the bidders organised in the same fashion; (b) a quick understanding of the compliance of each bidder with key requirements; and (c) a consistent tabu­lation of plant data to facilitate bid evaluation. Thus it is understood that more detailed information regarding plant design and features is to be found in the technical descriptions, drawings and data included by the bidder in other parts of the bid.

It is advisable for the technical data sheets to be organised into three sets, as follows:

1. Data sheets covering the main data at the overall plant level, to provide a quick overview of plant design parameters and features.

2. Data sheets addressing compliance with the main top-level design objectives as they are specified in the BIS and organised by project discipline (e. g. licensing and regulations; nuclear safety; civil-structural; NSSS; systems and equipment; turbine-generator and steam cycle; rad — waste systems; electrical systems; I&C; BOP; project implementation).

3. Data sheets listing the main technical data (i. e. performance, design conditions, operating conditions, materials, quality classification, codes and standards, etc.) of main plant structures, systems and components. This third set of technical data sheets can be organised as follows: NSSS systems and components (e. g. reactor pressure vessel, steam generators, main coolant pumps); emergency core cooling systems (ECCS); reactor auxiliary systems, containment systems, nuclear fuel supply and han­dling; radwaste systems; plant auxiliary systems; electrical systems; I&C systems; turbine-generator and auxiliaries; steam-cycle systems (main steam, feedwater, condensate, etc.); and cooling water system.

The RB must verify compliance with applicable regulatory requirements and with the license terms and conditions during each phase in the life of the NPP. Such verifications are achieved through regulatory inspections, oversight procedures, and analysis of the multiple progress and evaluation reports provided by the licensee.

20.6.1 Regulatory inspections

Regulatory inspections are carried out during each phase in the life of the NPP with the aim of checking the safety compliance of the NPP, through physical verification of the condition of its SSCs and by auditing of opera­tional records. In many countries, the RB keeps resident inspectors in a given plant or clusters of plants to continually oversee the safety of the installation. The RB should specify the frequency, lay down formal procedures and authorize appropriate staff for carrying out these inspec­tions. However, special inspections can be conducted when considered necessary.

The inspection findings should be discussed with senior managers of the NPP to resolve any anomalies and thereafter the inspection report should be submitted for review by the appropriate safety committees. RBs have established formal procedures on how to write inspection reports and how to formally include in such reports the licensee observations and claims to be considered before any regulatory action is taken.

The recommendations arising from the inspections and from a review of the inspection reports should be categorized according to their importance to safety following the criteria specified by the RB. Implementation of the recommendations should be done according to the schedule agreed upon between the RB and the operating organization, and the RB staff should follow this up.

Although the human resources development programme for each country has its own unique characteristics that should be identified considering the above-mentioned factors, in the following paragraphs the human resources needs for different stakeholders will be analysed according to their main mission.

The ranges presented in the following paragraphs should be interpreted as indications of orders of magnitude of the number of specialists required for each group of activities for a new NPP with a single unit. Most data have been extracted and adapted from IAEA (2007a).

Table 6.2 summarizes the human resources requirements according to different functions or activities to be accomplished during the implementa­tion of the nuclear programme. Statistics regarding future nuclear employ­ment in the USA can be found in Clean and Safe Energy Casenergy Coalition (2009).

To help point the way towards a globalizing nuclear profession, the World Nuclear Association has worked with the IAEA, WANO and the NEA to create the new World Nuclear University. The WNU is a partnership in which these four global organizations cooperate together, and with leading institutions of nuclear learning, in activities to enhance nuclear education and leadership for the twenty-first century. The WNU partnership is sup­ported by a small multinational secretariat in London composed of nuclear professionals seconded by key governments and nuclear enterprises.

The flagship of the partnership is the WNU Summer Institute, an annual six-week event designed to educate and inspire an international group of young nuclear professionals who show promise as future leaders in the world of nuclear science and technology.

A NPP comprises a large number of structures, systems and components and these need to be maintained in a good state of repair for safe and efficient operation. Maintenance can be largely divided into preventive, predictive and breakdown maintenance. All preventive maintenance activ­ities should be well planned according to manufacturers’ recommenda­tions and executed by well-trained personnel. These schedules shall be suitably revised from time to time based on actual experience. Modern NPPs have sufficient redundancy for equipment and instrumentation items that are safety related or which are needed to be taken out of service for maintenance or calibration with the NPP in operation. Some of this equip­ment or components may be radioactively contaminated and hence will have to be decontaminated prior to maintenance work. Where this is not possible, maintenance may have to be done in shops that are equipped to handle contaminated parts. For predictive maintenance, the components have to be kept under surveillance to monitor any degradation such as by condition monitoring techniques or by trending their performance. Maintenance work is then done to prevent breakdown while in service. For certain redundant safety-related components the technical specifica­tions for operation prescribe the allowed outage time. The plant mainte­nance groups should be well equipped to complete maintenance work on such items and return them to service within the permitted time to avoid forced shutdown of the NPP.

From the foregoing it can be seen that a high level of technical compe­tence for all types of maintenance work must be developed in the plant staff. This can be achieved by getting some personnel trained in mainte­nance at other NPPs of similar design and by equipment manufacturers. These personnel in turn should train the larger number of maintenance personnel at plant site. For overhauling some of the equipment of a special­ized nature such as the turbine generator, it may be necessary to engage the manufacturer’s personnel during planned outages of the NPP. However, the overall responsibility for getting the work carried out and bringing the equipment back to service must rest with the plant personnel. Several maintenance activities are undertaken during planned outages such as the refuelling outage. The duration of such outages and consequently the plant load factor is heavily dependent on the capability of the maintenance per­sonnel to complete the work in a timely manner while maintaining a high level of quality in the work performed. It must be remembered that a well — designed and well-operated NPP can give plant load factors in excess of 90% but this is possible only when it is maintained by personnel with a high level of technical skills and in the most professional manner.

S. BILBAO Y LEON, Virginia Commonwealth University, USA and J. H. CHOI, J. CLEVELAND, I. KHAMIS, A. RAO, A. STANCULESCU, H. SUBKI and B. TYOBEKA, International Atomic Energy Agency (IAEA), Austria

Abstract: This chapter discusses the various nuclear technologies currently available for near-term deployment, as well as those in advanced stages of development that are expected to become available in the near to medium term. The chapter includes a brief overview of innovative nuclear technologies proposed for the longer term. Finally, the chapter offers some insights about the use of advanced nuclear technologies for non-electrical applications.

Key words: advanced nuclear reactor designs, evolutionary nuclear reactor designs, innovative nuclear reactor designs.

9.1 Introduction

In addition to the support required in the development of the infrastructure necessary to deploy a new nuclear program, newcomer countries have also indicated a desire to receive guidance in the process of evaluating the dif­ferent nuclear technology options.

Countries, both those considering their first nuclear power plant and those with an existing nuclear power program, are interested in having ready access to the most up-to-date information about all available nuclear reactor designs as well as important development trends. To meet this need, the International Atomic Energy Agency (IAEA) has developed the Advanced Reactors Information System (ARIS) (IAEA, 2010), a web — accessible database that provides Member States with balanced, compre­hensive and always up-to-date information about all advanced reactor designs and concepts.

In addition to having accurate information about the various nuclear technologies available, the key technical characteristics of a particular nuclear project should be clearly understood and specified at the onset of

This chapter is the copyright of the International Atomic Energy Agency (IAEA) and is reproduced by the Publisher with the IAEA’s permission. Any further use or reproduction of the chapter, in whole or in part, requires the permission of the IAEA. The chapter has been written by a staff member of the IAEA in his personal capacity and not on behalf of the IAEA or the Director General of the IAEA. The views expressed in the chapter are not necessarily those of the IAEA and that the IAEA disclaims all liability in connection with the chapter and any use made thereof.

261

the project. In this way both the technical and economic benefits of the alternative nuclear power plant designs and associated technologies can be objectively assessed against the situation and the needs of each country, and the most suitable design can be selected. Nations need to follow a design — neutral systematic approach that evaluates the technical merits of the various nuclear power plant technologies available on the market based on each country’s needs and requirements.

The objective of this chapter is to help the reader differentiate among the different kinds of nuclear reactors and develop a clear picture about the current status of nuclear power technology. The chapter describes in some detail the most relevant nuclear reactor designs developed by all the suppliers/designer organizations in the world, highlights their advantages and disadvantages, and provides an update about the status of development and deployment of each one of them.

Because nuclear technology can also be used for many applications in addition to the production of electricity, and because many newcomer coun­tries are interested in these non-electric applications almost as much as they are in the production of nuclear electricity, the chapter also provides a summary of the various non-electric applications of nuclear power and the technology needed to effectively deploy them.

GE Hitachi Nuclear Energy’s Economic Simplified Boiling Water Reactor (ESBWR) is a 1520 MWe power plant design based on the earlier 670 MWe Simplified Boiling Water Reactor (SBWR) design. The ESBWR design incorporates innovative, yet proven, features to further simplify an inher­ently simple direct cycle nuclear plant. The ESBWR completely relies on passive safety systems for both normal and off-normal operating conditions, such as natural circulation, isolation condensers or gravity-driven cooling systems. The core of the ESBWR is shorter and the overall vessel height is larger than a conventional BWR, in an effort to maximize natural circula­tion and avoid the use of recirculation pumps or their associated piping. The US NRC provided the ESBWR with an advanced Safety Evaluation Report (SER) with no open items in August 2010, and the final design certification is expected by September 2011.