About 24% of electricity was generated by nuclear power plants in Japan in 2008, approximately 65.7% from fossil sources (natural gas, coal and oil), and 7.7% by hydropower plants [7.4].

According to Table 7.10, advanced SMRs are not competitive with large nuclear power plants. However, because of the very high costs of generating electricity on coal — and gas-fired plants6, SMRs — as well as NPPs with large reactors — are competitive in these segments of the electricity market. In such conditions the choice between SMRs and large reactors would, inter alia, be defined by the site availability and characteristics. In the case of Japan, clustering of NPPs with large reactors on the sites has been considered more effective, resulting in a complete abandonment of the national SMR option.

If the interest rate is increased up to 10% (which is not the current case in Japan), some SMRs seem to become competitive, especially those with short construction periods (e. g. multi-module plants).

Because of complicated geographical conditions and high level of seismic design requirements, nuclear power plants in Japan strongly compete with large hydroelectric plants, see Table 7.10.

6 Japan imports all the fossil fuel needed for these plants.

104

To evaluate a deployment potential of NPPs with SMRs in regulated markets, the LUEC estimates for SMRs based plants presented in Table 7.7 were compared to the LUEC values for electricity generating plants based on the following other technologies:

• nuclear power plants with large reactors;

• coal-fired plants;

• gas-fired plants;

[60] renewable plants, including onshore wind, offshore wind, solar, biomass and biogas, and large hydroelectric power plants.

The LUEC data for the power plants using technologies other than SMRs were taken from tables 3.7(a-d) of reference [7.1] and correspond to the most recent projections for electricity generation costs (for the year 2010).

With data from [7.1] used as a reference, the evaluation performed in this and the following sections is limited to the generation of electricity, co-generation of electricity and heat in areas with

[61] The LUEC values for coal and gas in Table 7.8 do not include carbon pricing

The situation in the Russian Federation is notable for the actual discount rate being closer to 10% than to 5%. Despite this, the nuclear option competes well with all the available technologies producing electricity, see Table 7.12.

It should be noted that small floating NPPs with the PWR-8 and PWR-35 twin-unit plants (based on the Russian ABV and the KLT-40S designs) do not compete in the conditions of the “on-grid”

[63] Large number of assumptions made in the evaluation of competitiveness of SMR based CHPs makes it impossible to draw any meaningful conclusions regarding particular configurations and types of the SMR based plants.

[64] In Brazil, more that 70% of electricity is generated from hydroelectric power plants offering very low cost electricity. Other sources of electricity, including nuclear power plants (with large reactors or SMRs), have higher electricity generation costs.

[65] Currently a very large part of the electricity generated in Indonesia is based on coal, oil and natural gas. Reference [7.10] indicates the growth rate of the electricity demand in Eastern Kalimantan of 12% per year to be unbalanced with the capabilities of the State Electricity Company which is able to provide only an 8.5% per year capacity growth rate using small and medium-sized power plants on organic fuel. The tariff for electricity produced by coal-fired plants could be as high as 110 USD/MWh. In addition to electricity, East Kalimantan also faces the unbalanced consumption and production of potable water. For example, in 2007 the demand for water in East Kalimantan was 437 221 m3/day, while the local water company owned by the government was able to provide only 253 991 m3/day of potable water causing a deficit of 183 300 m3/day. Maximum plant capacity in East Kalimantan is limited by approximately 400 MWe from the conditions of compatibility with small electricity grids.

[66] Vertical peak ground acceleration is conventionally assumed to be 2/3 of the horizontal one or less.

[67] ~3.5-4.4 on the Japan Meteorological Agency (JMA) seismic intensity scale [6.12].

[68] ~6 on the JMA scale.

[69] Detailed design has been completed for the VK-300, while the CCR is still at a conceptual design stage.

[70] Plans to increase the AHWR output up to 500 MWe are being discussed.

[71] The most recent PBMR design had reverted to an indirect Rankine cycle.

[72] 210Po is a volatile а-emitter produced via reaction 209Bi + p ^ 209Po + n; it has a half life of ~138 days and is lethal for a human being when inhaled or digested.

[73] There is no water in the pool when a shut down lead-bismuth cooled reactor is being heated to prevent freezing of the coolant at 125oC.

[74] This table has been compiled using the same sources as Table 4.7 in Section 4.3.

[75] Early in 2010, the financial collapse of the vendor, PBMR Pty. (South Africa), resulted in the abandonment of the original deployment plan; however, the licensing pre-application was still indicated on the US NRC web-site (as of the end of 2010) , see reference [7.1].

[76] i. e., a probability — consequences curve correlated with each level of the defence in depth.

[77] Taking into account non-electrical applications.

[78] Late in 2010 the Westinghouse Electric Company stopped the development of the IRIS project and announced it would go with an alternative integral design PWR of a 200 MWe class. No technical details of this new SMR were available as of January 2011.

[79] From the condition that an unplanned NPP shutdown does not disrupt the stable grid operation.

[80] One of the main factors negatively affecting the investment component of LUEC for all SMRs is the economy of scale. Depending on the power level of the plant, the specific (per

[81] Regarding the operation and maintenance (O&M) and fuel cycle components of the LUEC for advanced SMRs, the tentative conclusion is that their sum is likely to be close to the

[82] In Brazil, more that 70% of electricity is generated from the hydroelectric power plants offering very low cost electricity. Other sources of electricity, including nuclear power plants (with large reactors or SMR), have higher electricity generation costs.

[83] On their own, the “by design” safety features used in SMR are in most cases not size — dependent and could be applied in the reactors of larger capacity. However, SMRs offer broader possibilities to incorporate such features with a higher efficacy.

[84] Non-water-cooled SMR may face licensing challenges in those countries where national regulations are not technology neutral, firmly rooted in the established water-cooled reactor practice and regulation based. Absence of regulatory staff familiar with non water cooled reactor technologies may also pose a problem.

Many SMRs addressed in this section are designed (or are being designed) for both baseload as well as load-following operation. Where specified, the magnitude and rate of (daily) power variations and number of power level switches for SMRs do not differ much from those of the state-of-the-art large reactors[35]. The SMR derived from marine reactors may even have better manoeuvring capabilities than large reactors, since the original propulsion reactors are specifically designed to allow rapid power variations in a wide power range. However, the precise information on manoeuvring capabilities of advanced SMRs is currently not available.

For some co-generation plants with SMRs, e. g., the NuScale [4.8], it is proposed to change the ratio of electricity and desalinated water production at a constant thermal output of the reactor, which is expected to enable load-following operation precisely matching hourly load changes during the day.

Regarding non water-cooled SMRs, load following capability is in fact linked to the low linear heat rate of the fuel elements. For example, load-following is generally not considered for large capacity sodium cooled reactors where the linear heat rate of fuel elements can be as high as 485 W/cm. In the small sodium cooled 4S (see Section 4.2.5) the linear heat generation rate is only

39 W/cm, which is said to enable load-following operation with controlled changes to the reactor power level[36].

Regarding the compatibility with electricity grids, the general “rule of thumb” is that the unit size of a power plant should not exceed 10% of the overall grid capacity[37] [4.42]. This requirement could, perhaps, be relaxed by some appropriate smart grid designs, but this is still subject to research. By definition NPPs with SMRs can be more easily deployed using existing grid capacity, when compared to large reactors or any other large sources of power.

References

[4.1] IAEA (2006), Status of Innovative Small and Medium Sized Reactor Designs 2005: Reactors

with Conventional Refuelling Schemes, IAEA-TECDOC-1485, Vienna, Austria.

[4.2] IAEA (2007), Status of Small Reactor Designs without On-site Refuelling, IAEA-TECDOC-

1536, Vienna, Austria.

[4.3] IAEA (2010), “International Status and Prospects of Nuclear Power”. Report by the Director

General, Vienna, Austria:

www. iaea. org/About/Policy/GC/GC54/GC54InfDocuments/English/gc54inf-5_en. pdf

[4.4] IAEA, Power Reactor Information System (PRIS), home page: www. iaea. org/programmes/a2/

[4.5] IAEA (2004), Status of Advanced Light Water Reactor Designs 2004, IAEA-TECDOC-1391,

Vienna, Austria.

[4.6] Zee, S. K., et al. (2007), “Design Report for SMART Reactor System Development”,

KAERI/TR-2846/2007, KAERI, Taejon.

[4.7] Babcock & Wilcox Modular Nuclear Energy (2010), “B&W mPower Brochure”:

www. babcock. com/library/pdf/E2011002.pdf

[4.8] NuScale Power (2008), “Overview of NuScale Technology”:

www. nuscalepower. com/ot-Scalable-Nuclear-Power-Technology. php

[4.9] IAEA (1995), Design and Development Status of Small and Medium Reactor Systems 1995,

IAEA-TECDOC-881, Vienna, Austria.

[4.10] Heki, H., et al. (2006), “Design Study Status of Compact Containment BWR”, (Proc. Int. Congress on Advances in Nuclear Power Plants, Reno, NV, United States, June 4-8, 2006), ICAPP’06, No. 6372.

[4.11] IAEA (2009), Design Features to Achieve Defence in Depth in Small and Medium Sized Reactors, IAEA Nuclear Energy Series Report NP-T-2.2, Vienna, Austria.

[4.12] IAEA (2008), Liquid Metal Cooled Reactors: Experience in Design and Operation, IAEA — TECDOC-1569, Vienna, Austria.

[4.13] AKME Engineering company web page: www. akmeengineering. com

[4.14] Il Soon Hwang, et al. (2008), “Development of PASCAR (Proliferation-resistant, Accident — tolerant, Self-sustainable, Capsular, Assured Reactor). Design and Safety Analysis”, OECD/NEA Information Exchange Meeting on Partitioning and Transmutation 2008, Mito, Japan.

[4.15] Hyperion Power Generation (2008), “Hyperion Power Module” (White Paper), HPG,

United States: www. hyperionpowergeneration. com

[4.16] OKBM update on the KLT-40S design descriptions in IAEA-TECDOC-1391 and IAEA Nuclear Energy Series Report NP-T-2.2, OKBM Afrikantov, the Russian Federation, 2009.

[4.17] Zuoyi Zhang, Zongxin Wu, Dazhong Wang, Yuanhui Xu, Yuliang Sun, Fu Li, Yujie Dong (2009), “Current status and technical description of Chinese 2*250MWth HTR-PM demonstration plant”, Nuclear Engineering and Design 239, 1212-1219.

[4.18] OKBM update on the ABV design description in IAEA-TECDOC-1536, OKBM Afrikantov, the Russian Federation, 2009.

[4.19] KAERI update on the SMART design description in IAEA-TECDOC-1485, KAERI, Republic of Korea, 2009.

[4.20] CNEA update on the CAREM design description in IAEA-TECDOC-1485, CNEA, Argentina, 2009.

[4.21] U. S. Nuclear Regulatory Commission, Advanced Reactors: www. nrc. gov/reactors/advanced. html

[4.22] Westinghouse Electric Company update on the IRIS design description in IAEA-TECDOC — 1485, Westinghouse Electric Company, United States, 2009.

[4.23] BARC update on the AHWR design description in IAEA-TECDOC-1485, BARC, India, 2009.

[4.24] OKBM update on the VBER-300 design description in IAEA-TECDOC-1536, OKBM frikantov, Russian Federation, 2009.

[4.25] Jia Haijun, Zhang Yajun (2008), “Nuclear Seawater Desalination Plant Coupled with 200 MW Heating Reactor”, International Journal of Nuclear Desalination 2008, Jeddah, Saudi Arabia, (Session 7/No. 1)

[4.26] IAEA (2009), Common User Considerations (CUC) by Developing Countries for Future Nuclear Energy Systems: Report of Stage 1, IAEA Nuclear Energy Series NP-T-2.1, Vienna, Austria.

[4.27] CANDU-6 Technical Summary, AECL, Canada: www. aecl. ca/Assets/Publications/C6-Technical-Summary. pdf? method=1

[4.28] Enhanced CANDU-6 Technical Summary, AECL, Canada: www. aecl. ca/Assets/Publications/EC6-TS_Eng. pdf

[4.29] IAEA (2009), Design Features to Achieve Defence in Depth in Small and Medium Sized Reactors, IAEA Nuclear Energy Series Report NP-T-2.2, Vienna, Austria.

[4.30] IAEA (2007), Status of Nuclear Desalination in IAEA Member States, IAEA-TECDOC-1524.

[4.31] IEA/NEA (2010), Projected Costs of Generating Electricity: 2010 Edition, OECD Publications, Paris, France.

[4.32] IAEA (2008), Energy, Electricity and Nuclear Power for the period up to 2030, Reference Data Series No. 1, Vienna, Austria.

[4.33] China State Power Information Network, Power Sources — Nuclear Power:

www. sp -china. com/powerSources/np. html

[4.34] Thakur, S. (2007), Positive experience with SMRs in India, lessons learned in previous two decades and future plans, NPCIL, India.

[4.35] Antony, A. (2008), Economic Competitiveness of the Indian Advanced Heavy Water Reactor (AHWR), BARC, India.

[4.36] IAEA (2002), Heavy Water Reactors: Status and Projected Development. IAEA Technical Report Series TRS-407, Vienna, Austria.

[4.37] Il Soon Hwang, et al, “PASCAR-DEMO — a Small Modular Reactor for PEACER Demonstration”, KNS spring, 2008.

[4.38] Il Soon Hwang (NUTRECK, SNU, Republic of Korea). Private communication, 2009.

[4.39] Measuring Worth: www. measuringworth. com/uscompare.

[4.40] Measuring Worth: www. measuringworth. com/japancompare.

[4.41] Enhanced CANDU-6 Technical Summary, AECL, Canada: www. aecl. ca/Assets/Publications/EC6-TS_Eng. pdf

[4.42] IAEA (1983), Interaction of Grid Characteristics with Design and Performance of Nuclear Power Plants, A Guidebook, IAEA Technical Reports Series No. 224, Vienna, Austria.

[4.43] The European Utility Requirement (EUR) document, Volume 2 revision C, April 2001

[4.44] Power Reactor Innovative Small Module (PRISM) http://www. nrc. gov/reactors/advanced/prism. html

Recently the so-called “mini” or small and modular reactors have attracted much attention. Since 2008, several private companies have been created in the United States to support the design development, patenting, licensing and commercialisation of several new SMR concepts. Typically, the companies were created following the R&D and design development activities carried out by the US national laboratories and consulting companies. Eventually bigger private companies (including some propulsion reactor manufacturers) have followed the trend [5.1].

Table 5.1 lists the US concepts of small and modular reactors that were announced in the last few years. Table 5.1 includes the three SMR design concepts addressed in more detail in Section 4 of this report (the NuScale, the mPower, and the New Hyperion Power Module) and another design concept which is at an early design stage with prospects of further financing still unclear (the ARC-100).

The attributes of small and modular reactors mentioned cumulatively in [5.1, 5.2, 5.3, and 5.4]

are:

• Small reactor size allowing transportation by truck (as well as by rail or barge) and installation in proximity to the users, such as residential housing areas, hospitals, military bases, or large governmental complexes.

• Small absolute capital outlay and an option of flexible capacity addition/removal through modular approach to plant design, deemed attractive to private investors.

• Individual containments and turbine generators for each of the reactor modules.

• High levels of safety and security boosted by the underground location of the reactor module(s), see examples at Figure 5.1 and Figure 5.2.

• Factory assembly of the complete nuclear steam supply system (NSSS) and, therefore, short construction duration on site.

• Long refuelling interval and once-at-a-time whole core reloading on the site or at a centralised factory (as a future option). [38]

• Provision for flexible co-generation options (generating electricity with co-production of heat, desalinated water, synthetic fuels, hydrogen, etc.).

Table 5.2 shows how the above mentioned cumulative attributes are distributed among the US small and modular reactor designs.

Table 5.3 shows how the same attributes are distributed among the non-US small and modular reactor designs considered in this report.

The data presented in Table 5.1, Table 5.2 and Table 5.3 indicate that:

• The new small and modular (“mini”) reactor concepts being developed in the United States fit well into the technology lines described in Chapter 4.

• The new US small and modular reactors (NuScale, mPower, New Hyperion Power Module, and ARC-100) share many of their design attributes with other small reactor design concepts being developed in other countries. [39]

• Some of the SMR designs developed outside the United States offer plant configurations similar to those envisaged for the US small and modular reactors. As an example, the Japanese 4S offers an underground location for the reactor module but does not provide for a multi-module plant, see Figure 5.3; As another example, 4,-6- and 16-module plant options have been considered for the Russian SVBR-100. Some of these plant configurations provide partly-underground location for the reactor modules, see Figure 5.4.

• Even though some of the non-US SMR design concepts (as well as the US ARC-100) do not offer a flexible multi-module plant configuration, an option to cluster several plants on the same site still exists, potentially yielding certain economic benefits related to the sharing of auxiliary equipment and communications, and learning. Alternatively, single module or twin-unit plants with SMRs could be reconfigured for a flexible multi-module plant configuration at later design stages.

•

Sheltered underground location for reactor modules adds a degree of protection against aircraft crash but may pose challenges with respect to other site-specific external events, such as floods, see discussions in Section 6.8.2.

The fast spectrum sodium — and lead-bismuth cooled SMRs from Table 5.2 and Table 5.3, with the exception of the Korean PASCAR, share another common attribute — they provide for an initial fuel load based on enriched uranium rather than an uranium and plutonium mixture. The uranium enrichment is slightly below 20%.

The SVBR-100, the New Hyperion Power Module, and the ARC-100 are reported to be capable of operation with the initial uranium fuel load including a fraction of non-reprocessed spent nuclear fuel from present day light water reactors (with fission products). For the SVBR-100 this fraction is evaluated as 12%weight [5.6], while for the ARC-100 — as 25%

weight

Generically, all fast spectrum small and modular reactors are being designed to operate in a closed nuclear fuel cycle[40]. Because of a long refuelling interval (10-30 years) they do not pose a requirement for near-term availability of the reprocessing technologies, leaving a time lag for such technologies to be developed and mastered on a commercial scale. The conversion ratio is typically high, slightly below 1.0, which means that the reactor breeds almost as much fissile material as it consumes during operation. The spent fuel, after cooling and reprocessing, can be reloaded in the core with an addition of natural or depleted uranium. The reprocessing would then be limited to removal of the fission products without further separation of heavy nuclides.

The attributes of small and modular reactors, such as small upfront capital investments, short on­site construction time (with the cost of financing accordingly reduced) and flexibility in plant configuration and applications, make such reactors attractive for private investors. However, since the nuclear industry is heavily regulated by public authorities, the public-private partnership seems to be the most probable form of cooperation to develop projects with small and modular reactors.

In the Russian Federation, the Joint Stock Company (JSC) "Evrosibenergo" and the State Atomic Energy Corporation "Rosatom" have created a public-private joint venture company “AKME Engineering” to advance the development, licensing and commercialization of the SVBR-100 project of a small lead-bismuth cooled reactor [5.8]. The near-term goal is to deploy the prototype on the site of the NIIAR research centre in Dimitrovgrad (Russian Federation) by 2017.

In the United States, formation of public-private partnership and licensing for the small and modular reactors is being supported by the Small and modular reactor programme of the Office of Advanced Reactor Concepts belonging to the Office of Nuclear Energy of the Department of Energy (DOE) [5.9]. This programme, started in May 2011, has a near-term priority to support licensing of two US designs of water cooled small and modular reactors. The target is to have these designs licensed for operation on the US territory by 2015 and to have them deployed by 2018. In the United States, development and deployment of small and modular reactors is viewed as a benefit to national industry as all (relatively small) components of such reactors could be produced indigenously [5.9].

References

[5.1] Babcock & Wilcox Modular Nuclear Energy, B&W mPower Brochure (2010):

www. babcock. com/library/pdf/E2011002.pdf

[5.2] NuScale Power, Overview of NuScale Technology (2008):

www. nuscalepower. com/ot-Scalable-Nuclear-Power-Technology. php

[5.3] Hyperion Power Generation (2008), Hyperion Power Module (White Paper), HPG,

United States: www. hyperionpowergeneration. com

[5.4] Advanced Reactor Concepts, LLC. ACR-100 Product Brochure:

www. advancedreactor. net/#/product-solutions/4537736534

[5.5] IAEA (2003), Power Reactors and Sub-Critical Blanket Systems with Lead and Lead-Bismuth as

Coolant and/or Target Material, IAEA-TECDOC-1348, Vienna, Austria.

[5.6] IAEA (2007), Status of Small Reactor Designs without On-site Refuelling,

IAEA-TECDOC-1536, Vienna, Austria

[5.7] General Atomics (2010), Energy Multiplier Module Fact Sheet,:

www. ga. com/energy/em2/pdf/FactSheet-TechnicalFactSheetEM2.pdf

[5.8] AKME Engineering company web page: www. akmeengineering. com

[5.9] Black, R. (2010), “DOE Programs for Small Modular Reactors and Advanced Reactor

Concepts”, Office of Advanced Reactor Concepts, Office of Nuclear Energy, US Department of Energy: www. nrc. gov/reading-rm/doc-collections/commission/slides/2010/20100406/black- 20100406.pdf

The information provided in Tables A.2.1-A2.6 of Appendix 2 indicates that passive safety systems are the preferred choice of the designers of many advanced SMRs. In a number of designs belonging to the technology lines of PWRs, advanced heavy water reactors, HTGRs, and sodium cooled and lead-bismuth cooled fast reactors the preferred strategy is to have all of the redundant and diverse safety systems passive and safety grade, while keeping the necessary normal operation active systems non-safety grade. In this, it is assumed that normal operation systems would on many occasions retain their performance in accidents and could, therefore, be used as a backup for dedicated safety systems. However, there is no unique strategy even within each selected technology line, and many designers still prefer to use plausible combinations of redundant and diverse active and passive systems. The latter choice might be facilitated by the considerations of plant economy as many active systems are well developed and require less materials and reactor building space to be implemented. The rule of thumb here is to have each of the independent safety systems, no matter whether active or passive, capable of a 100% performance of the required system function.

On their own, the passive safety systems implemented in advanced SMRs are not size specific and can be realised in the designs of large capacity as well.

It should be mentioned that since mid-1990s there are growing concerns about the reliability of passive safety systems implemented in advanced reactor designs. Appendix 1 of reference [8.5] lists the following reasons for these concerns:

• “Reliability of passive safety systems may not be understood so well as that of active safety systems.

• There may be a potential for undesired interaction of active and passive safety systems.

• It may be more difficult to “turn off’ an activated passive safety system, if so desired, after it has been passively actuated.”

Several methodologies targeted at quantification of the reliability of a passive safety system performance are being developed worldwide, with the two distinct approaches represented by the European Union’s RMPS [8.12] and the Indian APSRA [8.13]. A brief summary of these approaches is provided in the appendix I of reference [8.5]. In addition to this, since 2009 the IAEA has been conducting a coordinated research project to develop a common analysis-and-test based method for the assessment of passive safety system performance in advanced reactors [8.14].

Currently, all of the above mentioned methodologies are at a preliminary development stage and in none of the cases has a nuclear regulatory assessment being made. However, all of the methodologies are being effectively used for the optimisation of passive safety system design and the preliminary results show that passive safety systems could be made equally reliable or even more reliable compared to the active ones.

Notwithstanding what was said above, there are examples of successful licensing of NPP projects with the reactors incorporating passive safety systems (the AP1000 in the United States and China; the KLT-40S in the Russian Federation, the VVER-1000 in the Russian Federation, China, India, and Iran). The validation of passive systems for all of these designs followed a well established approach including performance of the separate effect tests, development and validation of the codes, and performance of the integral tests [8.15].

At a very general level, SMRs could be divided into two major categories: traditional land-based nuclear power plants and transportable (e. g. barge-mounted) plants. Land-based SMRs could be assembled on-site (like large reactors) or fabricated and assembled in full at a factory. These options have very different effects on the competitiveness of each particular project.

Factors influencing capital investment costs

One of the main factors negatively affecting the investment component of LUEC for all SMRs is the economy of scale. Depending on the power level of the plant, the specific (per kWe) capital costs of SMRs are expected to be tens to hundreds of percents higher than for large reactors. While the lack of economy of scale increases the specific capital costs and, therefore, the total investment, other SMR features are put forward by the designers to improve their economic outlook:

• Construction duration. According to the vendors’ estimates the construction duration of SMRs could be significantly shorter compared to large reactors, especially in the case of factory-assembled reactors. This results in an important economy in the costs of financing, which is particularly important if the discount rate is high (the specific capital costs could be reduced by up to 20%).

• First-of-a-kind factors and economy of subsequent units on the site/multi-module plants. According to reported experience, the FOAK plants are 15-55% more expensive than the subsequent serial units. Building several reactors on the same site is usually cheaper than building a NPP with a single reactor. These factors apply both to large reactors and SMRs. However, if the overall capacity requirement for the site is limited to, say, 1-2 GWe, the effects of learning in construction and sharing of the infrastructure on the site will be stronger if building several plants. The reduction in effective (per unit) capital cost of SMRs could be 10-25%.

• Economy of subsequent factory fabricated units. In contrast to large reactors, some SMRs could be fully factory manufactured and assembled, and then transported (in the assembled form) to the deployment site. Factory fabrication is also subject to learning which could contribute positively to a reduction in capital costs of SMRs and in the investment component of the LUEC. The magnitude of the effects of learning in factory fabrication of SMRs is considered to be comparable to that of the effects for on-site built plants (up to 30-40% in capital cost reduction, on the total). [2]

• Full factory fabrication of a barge-mounted plant. According to the vendors’ data, a full factory fabricated barge-mounted NPP could be 20% less expensive compared to a land — based NPP with a SMR of the same type. The corresponding improvement of the LUEC would, however, be limited to 10% because of increased operation and maintenance costs for a barge-mounted plant.

The possible impact of the factors above and their combined action were assessed though a number of case studies presented in this report. However, even if all of the above mentioned factors are taken into account, the investment component of the LUEC for a SMR would be at least 10-40% higher than in the case of a NPP with a large reactor in the same country.

Another notable feature of SMRs is that the total overnight costs are significantly lower (in absolute value) than the costs of large NPPs. This could make them attractive for investors in liberalised energy markets and to countries willing to develop their nuclear programme but having limited financial power.

Also, SMRs allow for incremental building which reduces considerably the capital-at-risk, compared to conventional large nuclear power plants.

The absolute values of decommissioning costs are not available for any of the SMRs addressed in this report. However, the designers of SMRs often mention that decommissioning costs are expected to be relatively low, with respect to large-size reactors.

Generally speaking decommissioning appears technically easier for full factory-assembled reactors, as they could be transported back to the factory in an assembled form, in the same way as they were brought to the site for operation [6.2]. The dismantling and recycling of the components of a decommissioned NPP at a centralised factory is expected to be cheaper compared to the on-site operations, in particular, due to the economy of scale associated with the centralised factory [6.2]. The decommissioning of barge-mounted reactors seems particularly simplified since they could be towed back to the factory leaving no traces of plant operation on the site.

Even if the absolute value of the decommissioning cost is important, the impact of the decommissioning cost on the LUEC is small (less than a percent, see Table 6.1) since it is discounted over a long period of time (40-60 years) corresponding to the operation of the plant.

The present NEA study is a synthesis report on the development status and deployment potential of SMRs. It brings together the information provided in a variety of recent publications in this field, and presents the characterisation of SMRs already available for deployment and those that are expected to become available in the next 10-15 years.

Particular attention is paid to the economics of such reactors, and the various factors affecting their competitiveness are analysed and discussed. Vendors’ data on the economics of different designs is compared with the independent quantitative estimates of the electricity generating costs, and the deployment potential of SMRs in a number of markets and geographic locations is assessed.

The study also highlights the safety features and licensing issues regarding such reactors, although the Fukushima Dai-ichi accident might have a significant impact on the design and licensing of SMRs.

For this study, a SMR definition supported by the International Atomic Energy Agency (IAEA) was used, according to which “small reactors are reactors with the equivalent[77] electric power less than 300 MW, medium-sized reactors are reactors with the equivalent electric power between 300 and 700 MW". However, the main focus is on small reactors.

9.3 Summary

SMR characterisation (general)

Regarding the SMR characterisation, the conclusions are as follows:

• On a fundamental level, nuclear power plants with SMRs are not different from those with large reactors. The reasons to consider SMRs separately are:

— higher degree of innovation implemented in their designs; and

— specific conditions and requirements of the target markets, which are often substantially different from those of the nuclear power plants (NPPs) with conventional large reactors.

• Recent publications on SMRs point to the following two general classes of SMR applications:

— Niche applications in remote or isolated areas where large generating capacities are not needed, the electrical grids are poorly developed or inexistent, and where the non­electrical products (such as heat or desalinated water) are as a bare necessity as the electricity is.

— Traditional deployment and direct competition with NPPs with large reactors. In this, it is noted that the upfront capital investment for one unit of a SMR is significantly smaller than for a large reactor. Thus there is flexibility in incremental capacity increase, resulting in smaller financial risks and making such reactors potentially attractive to investors.

Over the years, the IAEA has published a number of comprehensive reports on design status of the advanced reactors belonging to different technology lines, including SMRs. These reports contain some useful definitions which are also adopted in the present report.

According to the IAEA [2.1, 2.2]:

• Small reactors are reactors with the equivalent[11] electric power less than 300 MW.

• Medium-sized reactors are reactors with the equivalent electric power between 300 and 700 MW.

The IAEA-TECDOC-936 “Terms for describing new, advanced nuclear power plants” [2.3] defines an:

• Advanced design as a “design of current interest for which improvement over its predecessors and/or existing designs is expected”.

A continued advanced reactor development project passes sequentially through the design stages of conceptual design, basic (or preliminary) design and, finally, detailed design. The attributes of these design stages are detailed in the IAEA-TECDOC-881 [2.4]. In short:

• the conceptual design stage results in the development of “initial concept and plant layout”;

• the basic (or preliminary) design stage ends up with the “essential R&D completed (except non-critical items)”; and

• the detailed design stage yields the “complete design of the plant, except very minor items. It can be unified (for example, for an envelope of site conditions) or site-specific”.

According to the definition given in IAEA-TECDOC-1536 [2.5]:

• Small reactors without on-site refuelling are reactors designed for infrequent replacement of well-contained fuel cassette(s) in a manner that prohibits clandestine diversion of nuclear fuel material.”

The above definition addresses both factory fabricated and fuelled reactors and the reactors for which infrequent reloading of the whole core is performed on the site. For the purposes of the present report, the IAEA definition [2.5] was not followed and the reactors with the above mentioned features were categorised separately.

• Distributed deployment refers to a situation when a NPP with a single reactor module or a twin-unit NPP is deployed on each of the many sites.

• Concentrated deployment assumes clustering of multiple NPPs, or construction of a multi­module plant, on a site.

All safety related terms used in Sections 6 and 7 of this report follow the definitions suggested in the IAEA Safety Glossary [2.6].

References

[2.1] IAEA (1997), “Introduction to Small and Medium Reactors in Developing Countries”,

Proceedings of two Advisory Group meetings held in Rabat, Morocco and Tunis, Tunisia, IAEA-TECDOC-999, Vienna, Austria.

[2.2] IAEA (2005), “Innovative Small and Medium Sized Reactors: Design Features, Safety

Approaches and R&D Trends”, Final report of a technical meeting held in Vienna, 7-11 June 2004, IAEA-TECDOC-1451, Vienna, Austria.

[2.3] IAEA (1997), Terms for Describing New, Advanced Nuclear Power Plants, IAEA-TECDOC-

936, Vienna, Austria.

[2.4] IAEA (1995), Design and Development Status of Small and Medium Reactor Systems 1995,

IAEA-TECDOC-881, Vienna, Austria.

[2.5] IAEA (2007), Status of Small Reactor Designs without On-site Refuelling, IAEA-TECDOC-

1536, Vienna, Austria.

[2.6] IAEA (2007), IAEA Safety Glossary: 2007 Edition, Vienna, Austria.

At the time of this report (2011) there were eight proven SMR designs with a prospect of international deployment, see Figure 3.1. Some of those designs have already been completed or are already in operation; basic characteristics of these designs are summarised[12] in Table 3.1.

Of these designs, the CANDU-6, the EC6 and the PHWR-220 are pressure-tube type heavy water reactors. The QP-300, CNP-600 and KLT-40S are pressurised water reactors. Most of the plants provide for both distributed and concentrated (several plants on a site) deployment. For a floating plant with two KLT-40S reactors, location of more than one barge on a site has not been considered yet. The EC6 provides for a twin-unit option, the KLT-40S is a twin-unit.

The construction period ranges from four to seven years, with the shortest one for the Russian KLT-40S and the longest one for the Chinese QP-300 and CNP-600.

All of the SMRs in Table 3.1 have containments, and the PHWR-220 and the KLT-40S offer a double containment.

Figure 3.1. SMRs available for commercial deployment in 2010

CANDU-6

EC6

QP300, CNP-600

PHWR-220,r PHWR-540 PHWR-700, <

OECD member countries

Candidates for accession

Enhanced Engagement countries

3.1 Land-based heavy water reactors (HWRs)

Except for EC6, all heavy water reactors from Table 3.1 have already been deployed in the country of origin and in some cases abroad. The CANDU-6 and the QP-300 have been deployed

internationally, and there are agreements to build more of these reactors in Romania and Pakistan, respectively. All deployments of the CANDU-6 since 1996, as well as all deployments of the PHWR-220 since 2000 are reported to have been accomplished on schedule (or even ahead of it) and without exceeding the budget [3.1, 3.2].

The CANDU-6 reactors are the newest in the CANDU series that have been deployed. The EC-6 is an evolutionary modification of the CANDU-6, based on the experience of the latest deployed CANDU-6 reactors.

The PHWR-220 is an Indian development from the previous low-power CANDU reactors. The safety features of the initial design have been improved resulting in increased level of safety of 15 reactors of this type currently operating in India [3.3].

The operational lifetime of currently available heavy water SMRs is typically 40 years, with the exception of the EC6 for which it is 60 years. The availability factors are quite competitive ranging between 79% and 90% for all SMRs in Table 3.1.

The CANDU-6, the EC6 and the PHWR are refuelled online. This is typical of all pressure tube type heavy water reactors.

A nuclear desalination option is being considered (but still not realised) for the Indian PHWR-220. More details about energy products of the SMR available for deployment can be found in Section 4.4.

3.2 Land-based pressurised water reactors (PWRs)

The QP300 is a low power conventional loop-type PWR with a maximal fuel burn-up of 30 MWday/kg and a one-year refuelling interval. In the CNP-600, fuel burn-up is increased to above 45 MWday/kg, and the refuelling interval is 1.5 years.

The QP300 and the CNP-600 use conventional refuelling in batches with a refuelling interval of 14 and 18 months, respectively.

The operational lifetime of QP300 is 40 years, and for the CNP-600 it is 60 years.

The QP300 incorporates a passive safety system of core flooding with borated water. The CNP-600 incorporates two passive safety systems, one for passive heat removal from the secondary side of the steam generator, and another for passive containment cooling.

3.3 Barge-mounted PWRs

The first-of-a-kind (FOAK) KLT-40S (see Figure 3.2) is the only barge-mounted SMRs in Table 3.1. It is currently under construction and expected to start operation in 2013. This plant offers a maximum of 80 MWe with the co-generation option disabled.

The projected plant operational lifetime is 40 years, and the targeted energy availability factor is

85%.

In the KLT-40S, the whole core is refuelled after the end of its fuel cycle. However, the fuel bundles are shuffled in the core with an interval of slightly above two years. Such refuelling scheme, in which fuel loading and unloading are performed on the barge, is adopted for the cermet fuel of slightly less than 20% enrichment in 235U used in KLT-40S.

* Here and after, the default is a single unit plant.

** During the 54th session of the IAEA General Conference in September 2010, India announced its intentions to also export NPPs with the indigenous PHWR-540 and PHWR-700 reactors (similar to PHWR-220 but having higher outputs of 540 and 700 MWe [gross]).

Of the SMR designs available for deployment, only the barge-mounted plant with the two KLT-40S reactors provides for operation in co-generation mode with co-production of heat for district heating.

The KLT-40S is based on the experience of about 6 500 reactor-years in operation of the Russian marine propulsion reactors [3.4]. The KLT-40S design is different from conventional PWRs. This difference is discussed in more detail below.

The KLT-40S offers a compact primary containment of less than 12 m in size. The plant surface area indicated for the KLT-40S is 8 000 m2 on the coast and 15 000 m2 in the bay.

References

[3.1] Enhanced CANDU-6 Technical Summary, AECL, Canada:

www. aecl. ca/Assets/Publications/EC6-TS_Eng. pdf

[3.2] India completes two CANDU reactors under budget, ahead of schedule:

www. democraticunderground. com/discuss/duboard. php? az=view_all&address=115×66278

[3.3] Deolalikar, R. (2008) “Safety in Nuclear Power Plants in India”, Indian Journal of Occupational

and Environmental Medicine, 200, Volume 12, Issue 3: www. ncbi. nlm. nih. gov/pmc/articles/PMC2796747/

[3.4] IAEA (2009), Design Features to Achieve Defence in Depth in Small and Medium Sized

Reactors, IAEA Nuclear Energy Series Report NP-T-2.2, Vienna, Austria.

[3.5] Nuclear Engineering International, January 2010:

www. neimagazine. com/journals/Power/NEI/January_2010/attachments/KLT-

40S%20Data%20&%20Diagram. pdf

[3.6] AECL, CANDU-6 Technical Summary, Canada:

www. aecl. ca/Assets/Publications/C6-Technical-Summary. pdf? method=1

[3.7] IAEA (1995), Design and Development Status of Small and Medium Reactor Systems 1995,

IAEA-TECDOC-881, Vienna, Austria.

[3.8] IAEA (2004), Status of Advanced Light Water Reactor Designs 2004, IAEA-TECDOC-1391,

Vienna, Austria.

In 2008, about 64.5% of electricity in the Republic of Korea was generated from fossil fuels (coal and natural gas), and approximately 34% from nuclear power plants. The contribution of hydropower and other sources is below 2% [7.4].

The pattern of SMR competitiveness in the Republic of Korea (Table 7.11) is generally similar to the one in Japan (Table 7.10). No data on renewable plants is available in reference [7.1] for the Republic of Korea.

As in the previous cases, nuclear plants are generally competitive with coal — and gas-fired plants[62], and NPPs with large reactors outperform those with SMRs. However, SMRs could be chosen

as a replacement or alternative to power plants using fossil fuel based on the siting considerations like the grid capacity, spinning reserve requirements, or the availability of water for cooling towers of a NPP.

6.1 Introduction and designers’ cost data for SMRs

6.1.1 Introduction and definition of Levelised Unit Electricity Cost (LUEC)

In order to assess the economics of different SMR projects and their deployment potential, this chapter provides the analysis and evaluation of the various economic factors affecting the competitiveness of SMRs.

The main figure of merit used in this chapter, as well as in the following Chapter 7, is the Levelised Unit Electricity Cost (LUEC). The LUEC formula and definitions are taken from reference [6.1] which mentions that:

the notion of levelised costs of electricity (LUEC[41]) is a handy tool for comparing the unit costs of different technologies over their economic life. It would correspond to the cost of an investor assuming the certainty of production costs and the stability of electricity prices. In other words, the discount rate used in LUEC calculations reflects the return on capital for an investor in the absence of specific market or technology risks.

All SMR deployment foreseen in the next decade would mainly take place in regulated electricity markets with loan guarantees and with more or less strictly regulated prices (see Figure 4.2), which justifies the selection of LUEC as a figure of merit for the competitiveness assessment of nearer-term SMRs.

The LUEC formula suggested in reference [6.1] reads:

where;

The amount of electricity produced in year “t”; Annual discount rate;

Investment cost in year “t”;

Operations and maintenance cost in year “t”; Fuel cost in year “t”;

Carbon cost in year “t”;

Decommissioning cost in year “t”.

The subscript “t” denotes the year in which the electricity production takes place or the expenses are made. The various assumptions used in deriving the formula (6.1) are discussed in detail in reference [6.1].

We summarise in Table 6.1 the structure of a nuclear generation cost, based on the data reported in reference [6.1]. It should be noted that those data refer mostly to NPPs of unit power higher than 1 000 MWe.

Table 6.1. Structure of nuclear electricity generation cost (for large reactors), based on [6.1]

Table 6.1 indicates that the total investment cost is a major constituent of LUEC for nuclear technology, with the O&M cost and the fuel cost making the next meaningful contributions. Carbon cost is zero since nuclear power plants emit no CO2 in operation. Finally, the contribution of the decommissioning cost (usually taken as about 15% of the overnight costs) to LUEC is always very small once discounted over 40-60 years, the typical operational lifetime of a nuclear plant.

As has been shown in the previous chapters, SMRs could be divided in to two major categories: “traditional” land-based nuclear power plants and barge-mounted plants (see Figure 6.1). Land-based reactors could be either factory-manufactured and assembled on-site, or fully built on-site. These realisations may have very different effects on the competitiveness of each particular project.

The objective of the following sections is to analyse and, where possible, to quantify the various factors affecting the competitiveness of SMRs (in terms of LUEC). An important concern while analysing the economics of SMRs, is the lack of data regarding their construction cost and the differences between SMR projects. In order to avoid those difficulties, we decided to adopt a scaling- law methodology [6.4] using the reliable data available for NPPs with large reactors (that have been deployed in recent years or are being deployed at the time of this report). The analyses performed are mostly based on comparative assessment of the impacts of the various factors on the economy of a NPP with SMR and that of a NPP with a large reactor.

After a brief summary of the designers’ LUEC values for SMRs in the following sub-section 6.1.2, we analyse in section 6.2 the factors affecting the investment cost, which are responsible for the major differences in the economies of SMRs and larger reactors.

The main factor negatively affecting the investment component of LUEC for all SMRs is the economy of scale. Depending on the power level of the plant, the specific (per kWe) capital costs of SMRs are expected to be tens to hundreds of percent higher than that for large reactors. While the economy of scale increases the specific capital costs and, therefore, the investment component of the LUEC for SMRs, other economic factors may tend to improve it. As an example:

• Construction duration. According to the vendors’ estimates the construction duration of SMRs is shorter than for large reactors.

• First-of-a-kind factors and economy of subsequent units on the site/multi-module plants. Building several reactors on the same site is usually cheaper than building a NPP with single units. This factor is the same for large reactors and SMRs. However, many SMRs are intended to be built in multiple modules and, thus, this factor can potentially play a larger role for SMRs than for large reactors.

• Economy of subsequent factory fabricated units. Different from large reactors, some SMRs could be manufactured and fully factory assembled, and then transported to the deployment site. This could potentially allow a decrease in the production cost (owing to the effects of production organisation and learning) and contribute positively to the competitiveness of SMRs.

• Design simplification. Some SMRs could offer a significant design simplification with respect to large reactors. If simplifications are possible, this would be a positive contribution to the competitiveness of SMRs.

To the extent possible, numerical estimates of each of the factors and their combined action are provided.