Category Archives: Small modular reactors (SMRs) the case of Russia

A proposed approach

I would suggest a consensus for a multinational framework for SMRs, as a formal statement of principle. This would be a tier below an internationally binding convention and could draw from models of the International Maritime Organization, International Civil Aviation Organization and the Naval Ship Code.

There are templates outside of the nuclear sector, for global fleet design and safety licensing, design change management and design authority, and requirements management, that have proven to be successful and could be employed (Soderholm, 2013). These include maritime regulation mechanisms for nuclear transport, and aircraft licensing. Aircraft licensing in particular could be a useful template to regard for standard SMR plants deployed in multiple countries (Goodman and Raetzke, 2013).

20.3 Conclusion

Keeping in mind the global consequences and effects of both disasters and advances, we should look at the risks of a lack of shared cooperative mechanisms for nuclear licensing, safety, monitoring and fuel. Developing countries and the rest of the world share so many systemic risks (economic, health, political, environmental) that new principles of sharing and cooperation, responsibility and mutual obligation will have to supersede narrower concerns such as sovereignty. Arguably, this is already taking place within the nuclear realm, under the NPT (nuclear non-proliferation treaty), and the concept would simply be extended, as far as SMRs are concerned, to the arenas of climate change and technology transfer. This idea deserves further study. SMRs, standardized, safety-enhanced, small-scale and flexible nuclear power technology, would be suitable for such new cooperative arrangements.

There will be a change of global understandings of risk, due to the raised awareness about climate change (because of acute observable effects and incidents). This will affect the economics of SMRs. The trade-offs and embedded risk biases will become more transparent in crisis. As a result, it is anticipated that emissions — reduction and climate-change strategies and policies will gain importance; and that nuclear safety monitoring, regulatory activity, and supply chain will be increasingly internationalized.

Above all, in the very idea of the ‘developing’ country, there is a continuum, the idea of progress. What is development for? We are aiming for the attainment of basic human functional capabilities by all, no matter where, with no exceptions (Nussbaum, 2000), for the ‘unfolding of powers that human beings bring into the world’ (Nussbaum, 2011).

To reiterate, SMRs provide the opportunity to go back to basic first principles (just as technology designers have) and consider what supporting institutions, infrastructure, and rationales for their use, are actually fit for purpose in a world of increasingly shared benefits and detriments.

We have to start somewhere.

[1] AP1000® is a trademark or registered trademark of Westinghouse Electric Company LLC, its subsidiaries and/or its affiliates in the United States of America and may be registered in other countries throughout the world. All rights reserved. Unauthorized use is strictly prohibited.

[2] Identification of relevant attributes for evaluation and selection, looking at the specific country taken into consideration.

2. Definition of measurement and evaluation process of each attribute (quantitative or qualitative, monetary or not, etc); each NPP design has to be evaluated on each attribute.

3. Definition of attribute’s hierarchical structure as required by a fuzzy analytical hierarchy process (AHP) application.

4. Expert elicitation to get attribute weights; each expert has to fill in a questionnaire of pairwise comparisons between attributes or groups of them. Fuzzy AHP permits judgements through linguistic variables (Yang and Chen, 2004).

5. Pairwise comparison matrices from different decision makers are aggregated through the geometric mean method presented in Kuo et al. (2002). Buckley’s method (Buckley, 1985) is then applied to the hierarchical structure and to get final attributes weights; these are fuzzy sets, so a decoding process is needed to obtain crisp values, the most common being the centroid method (Opricovic and Tzeng, 2004).

6. The TOPSIS method is applied for the final integration, looking at the five steps in Opricovic and Tzeng (2004).

20.6.2 Utilization of regional mechanisms

Second, a template for education, training, skills — and institution-building to support specifically SMR nuclear programs in multiple countries would shorten an indispensable rate-determining step (Goodman and Storey, 2012). A new country aiming to develop a nuclear regulatory body from scratch is presented with a daunting prospect, especially if the achievement of regulatory competence is tied to delivery of a national project to build a nuclear power plant for the first time.

Developing countries, grouped by region, could benefit from pooling of resources and sharing of processes. To lighten the institutional and infrastructural burden on individual developing countries, especially those that are poor or small, regionalizing SMR mechanisms would be useful.

This could mirror regional electricity grid interconnections such as the WAPP (West African Power Pool) or the SAPP (Southern African Power Pool), or regional economic communities such as ASEAN or that comprise mainly SIDS (small island developing states), such as CARICOM (the Caribbean Economic Community area).

Financing, grid installation, modernization and networking, nuclear regulation, operation, training, and monitoring are all good candidates for regionalization. Regional fleet mechanisms for a particular SMR type could be developed to handle all stages of project deployment, operation and decommissioning. This would be advantageous financially and also from the point of view of safety and security.

Regional regulators, especially or even specifically for pre-licensing of designs, would reduce the number of steps for an individual country regulator, and additionally improve financing potential, because of the shorter gap before the site-specific licensing and build process begins. Regional TSOs (technical safety organizations) could provide pooled technical resources, while maintaining the sovereignty and independence of the national regulator. A precursor could be ETSON (European Technical Safety Organisations Network), a European network of TSOs that support separate national regulators (ETSON, 2013).

To ease the burden on individual regulatory resources, the regional regulators would as a body or jointly perform a design verification delivering some form of ‘acceptable-design’ instrument, which could be conferred by an internationally recognized body. For example, the MDEP (Multinational Design Evaluation Program) could be extended into a group examination process towards common international design certification of SMRs (Goodman and Storey, 2012).

In the interim, innovative business models such as BOO; bilateral and regional tutelary programs; and international SMR-specific TSOs could help to bridge the human-resources gap for newcomer developing countries (Goodman and Raetzke, 2013). Developing countries will be able to operate and maintain SMR plants, by themselves, to global standards of safety.

Inclusion rather than ‘exceptionalism’

Third, these standards themselves, and regulations and international rules governing the use of nuclear power, need to be reconsidered in a more inclusive perspective. Instead of persisting in a ‘nuclear exceptionalism’ that no longer adequately serves the needs of the whole global community, a wider perspective should be taken (Abdel-Aziz et al., 2009; Hecht, 2012).

Regulatory innovators or change agents, would consider more, and perhaps different, factors than have hitherto influenced the formation of rules (Alexandre, 2011). A much broader spectrum of needs, capabilities, harms and risks — not just to humans, but to the environment and the atmosphere, and over time — will need to inform the design of more equitable rules for a more equitable and sustainable result (Sunstein, 2005; Mossman, 2006; Dell et al., 2012; Rowell, 2012; Kharecha and Hansen, 2013).

For example, a suite of goal-based SMR standards, set against the background of a more inclusive understanding of commensurable societal risks, costs and harms, could (directly or obliquely) take into consideration (among other factors) the radiological consequences of Fukushima, the higher cost of climate change to developing countries, the inherent and overlapping safety characteristics of the technology, and the social and economic detriment of lack of electricity (Wiener, 2004; Abdel-Aziz et al., 2009; IBRD, 2009; IAEA INPRO DF5, 2012; MacKay, 2009; UNDP, 2013).

SMR technologies in Japan

19.3.1 IMR

The IMR is an iPWR concepts and was proposed by MHI (Hibi et al., 2005) in cooperation with the JAPC (Japan Atomic Power Company) (Okazaki et al., 2011). The targets for the SMR design are summarized in Table 19.1. The schematic view of the reactor concept is shown in Figure 19.1. Its major specifications are summarized in Table 19.2. Although it is based on the PWR concept, boiling of the primary coolant, i. e. water, is allowed around the top area of the core (average void fraction at the core outlet is about 20%) and the core is cooled by the natural circulation of the coolant. Boiling of the core coolant is favourable to increase the driving force for the natural circulation core cooling. In this concept, the primary

Table 19.1 Targets for the SMR design

Power output: 300-600 MWe

Construction cost: The same as large reactors or less Capacity factor : More than 90%

Safety: At least as safe as existing plant Construction period: Less than 24 months License suitability: Suitable for the present license

Подпись: f4.1 mimage252image253Control rod drive (CRD) integrated into reactor










Reactor core J (short length)

Table 19.2 Major specifications of an IMR

Reactor power

350 MWe

Core thermal output

1000 MWt

System pressure

15.5 MPa

Primary system inlet/outlet temperature

573/618 K (300/345 °C)

Primary coolant flow rate

3.0 t/s

Steam temperature

562 K (289 °C)

Steam pressure

5 MPa

Core equivalent diameter

3 m

Core height

3.7 m

Refueling interval

26 months

Core average burnup

45 GWd/t

Capacity factor

90% or more

Construction period

Less than 24 months

cooling system and the steam generators (helical once-through type) are enclosed in the reactor pressure vessel and hence any large break LOCA is eliminated. In this reactor concept, several major components are eliminated, such as reactor coolant pumps, pressurizer and primary piping.

The power output is 350 MWe. The average discharge burnup is 45 GWd/t and the refueling interval is 26 months. Considering this longer lifetime of fuel rods as well as the increased coolant temperature up to 345 °C, a Zr-Nb alloy is applied to the cladding tube. The system pressure is 15.5 MPa and is the same pressure as in the normal PWR. For the safety system design, the IMR is significantly simplified. That is, it does not require the ECCS and only requires the steam generator cooling system for decay heat removal. The steam generator cooling system uses pumps, driven by diesel and gas turbine, as the active equipment.

As the IMR concept is different from the PWR in the flow characteristics, two experiments were conducted to check the flow characteristics inside the reactor vessel of the IMR. One was conducted under the actual conditions of the temperature, the pressure and the length of axial direction of IMR reactor system. Based on the results, it is confirmed that the natural circulation core cooling is available under the operation and design conditions of IMR. The other was conducted using a simulator of the main structure to confirm the three-dimensional flow characteristics in the reactor vessel. By the test, flow characteristics of the main structure inside reactor vessel could be understood and the methods for evaluating two-phase flow behaviours were developed.

For further developments of the IMR, optimization studies will be performed. In addition, possibilities to develop the concepts with various output ranges will be considered, utilizing the technology gained in the previous development. For example, a plant with 100 MWe output has been developed based on the IMR.

Sources of further information and advice

The references of this chapter provide further information on all items presented. For ongoing information on the status and evolution of the SMR program worldwide, consult the following website of the World Nuclear Association which is continuously updated to provide such SMR developments:

www. world-nuclear. org/info/Nuclear-Fuel-Cycle/Power-Reactors/Small-Nuclear- Power-Reactors/#.UV sR9EL3Cu4

The high cost of grid power compared to the developed world

The predicament of many developing countries is difficult: not only is electricity scarce and intermittent, it is also dear. In countries such as Ghana, electricity tariffs do not cover actual generation costs, resulting in major financial losses to the utility.

Ghana’s power tariffs are based on the costs of baseload hydropower priced at $0.05 per kilowatt-hour. However, the oil-based generation used to meet incremental demand is priced at more than $0.20. Since there is no mechanism for automatically adjusting tariffs, this situation generates annual financial losses for the Volta River Authority (VRA) of $400 million — 3 percent of GDP. (IBRD, 2010)

The handicap to economic activity is considerable: in 2007, it was reported that more than 2% of GDP was sacrificed to power shortfalls in vulnerable African countries (Wines, 2007). Nevertheless, although energy consumption is rising in developing countries throughout the world, it is worth remembering that the overall quantity is low in comparison with high-income countries. ‘[T]he annual average per capita consumption of electricity in the developing world is 1155 KWh and 10,198 kWh in high-income countries’ (IBRD, 2009).

Testing and verification

A number of test facilities have been set up, for example helium test loops and fuel handling test rigs. Experiments have been performed to test helium sealing, helium purification technologies and fuel handling components. Fuel burn-up has been researched. Progress has also been made in research of metallic alloy and insulation materials.

From April 2003 to September 2006, four experiments were completed to confirm and verify inherent safety features of modular HTRs: loss of offsite power without intervention, main helium blower shutdown without intervention, loss of main heat sink without intervention, and especially withdrawal of all rods without intervention. The residual heat of the reactor was carried out entirely passively and the reactor maintained its safety condition. All these experiments were authorized, guided and supervised by the national nuclear safety authority.


The CCR is a BWR and was proposed by the Toshiba Corporation (Heki et al., 2005) in cooperation with the JAPC (Okazaki et al., 2011). The targets for the design are the same as in the IMR and are summarized in Table 19.1. A schematic view of the reactor is shown in Figure 19.2. Its major specifications are summarized in Table 19.3. The core is shortened and cooled by the natural circulation of the coolant without the recirculation pumps. One of the characteristic features for the system simplification for this concept is the high pressure (about 4 MPa) resistant compact containment vessel without the suppression pool. The control rod drive mechanism is mounted at the top of the reactor vessel and, hence, the penetration at the bottom of the reactor vessel can be eliminated.

The power output is 423 MWe. The average discharge burnup is 45 GW d/t and the refueling interval is 24 months. The effective length of the core is shortened to 2.2 m to increase the driving force for the natural circulation core cooling. The system pressure is 7 MPa and is the same pressure as in the normal BWR. For the safety system design, the CCR concept is significantly simplified. That is, it does not require the ECCS and only requires the IC (isolation condensers) cooling system for decay heat removal. The IC system is a passive component system and is designed to remove decay heat for three days without any operation by the operators. As the control rod drive mechanism of the CCR is different from that of the BWR, and is also different from that in a PWR considering the operation in the steam environment, the abrasion-resistant tests for the material in the steam environment were conducted to confirm the applicability.

Containment Top mounted CRD

vessel. falling under gravity

Reactor pressure













f5.5 m

Reactor power

423 MWe

Core thermal output

1268 MWt

System pressure

7 MPa

Primary system inlet/outlet temperature

488/560 K (215/287 °C)

Primary coolant flow rate

3.3 t/s

Steam temperature

560 K (287 °C)

Steam pressure

7 MPa

Core equivalent diameter

3.5 m

Core height

2.2 m

Refueling interval

24 months

Core average burnup

45 GWd/t

Capacity factor

90% or more

Construction period

Less than 24 months

Table 19.3 Major specifications of a CCR


Figure 19.3 Construction cost evaluation of an IMR and a CCR.

From the economic point of view, the estimation results on the construction cost using the same evaluation method as for the large reactor are given in Figure 19.3 for the IMR and CCR concepts (Okazaki et al., 2011). In the figure, the unit construction cost per kWe are compared for the IMR, CCR and ABWR cases. The values are normalized by that of the ABWR case with 1356 MWe output. It can be recognized

that both the IMR and CCR concepts are at almost the same economic level as the typical large reactor of ABWR. The main reasons for this economic achievement are the simplification of the system by eliminating the systems and components and, hence, the resultant downsizing of the containment vessel. In addition, the downsizing of buildings due to the simplification of the systems and components enables the construction and civil engineering costs to be reduced. However, it should be noted that this evaluation is performed assuming that the new plant shares the port and the switching yard with the existing plant, and the additional costs for those facilities are required if the plant is established in a new site.

For further developments of CCR, optimization studies will be performed. In addition, possibilities of developing the concepts with various output range are considered, utilizing the technologies gained in the previous development. For example, a concept of a plant with 100 MWe output is developed based on the CCR concept.

Post-Fukushima actions

The CAREM prototype design was reviewed considering Fukushima experience. Topics like seismic requirements, loss of heat sink and black-out were considered. The design basis earthquake was reviewed. A risk-based criterion, based in Argentine Regulations AR 3.10.1 and AR 3.1.3, was used. CAREM-25 considers in its design base the loss of heat sink and station black-out during the grace period. Provisions were considered to allow, after the grace period, core decay heat removal and containment cooling using the fire extinguishing system or an autonomous system.

Energy infrastructure weakness

Diesel-generator backup systems are prevalent in the developing world, with high — cost, high-polluting fuel. Insufficient grid power leads to extra capital stress on private firms and families who can invest in backup generators, in order to maintain operations during routine brownouts and blackouts.

Average figures from enterprise surveys in (admittedly vast) ranges of countries in the Latin American-Caribbean region and Sub-Saharan African region show that percentages of manufacturing firms identifying electricity as a major constraint were, respectively, 37.6% and 50.3% (World Bank Enterprise Survey, 2012). From the perspective of domestic electricity users, the most vocal figures might be the average number of electrical outages in a typical month (3.7 in the Latin American — Caribbean region and 10.7 in the Sub-Saharan African region) and the duration of a typical electrical outage (2.1 hours and 6.6 hours, respectively).

This results in significant generator use for business, with 28.1% of Latin American — Caribbean firms owning a generator and 43.6% of Sub-Saharan African firms owning a generator — with concomitant fuel and operations and maintenance (O&M) costs (World Bank Enterprise Survey, 2012). State electricity firms also commonly resort to mobile generators for emergency power (New York Times, 2013).