Currently, there are two definitions of such reactors widely used in the literature: small and medium-sized reactors (SMRs) and small modular reactors. Small modular reactors have attracted much attention since 2008 when several very small reactors (less than 125 MWe) were being designed in the United States. In this study, the general class of reactors with effective electric power of less than 700 MWe will be considered, but the principal focus is on reactors of less than 300 MWe.

First, the report summarises 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, see Figure E.1.

In the second part of the report, the study provides an independent estimate of electricity generation costs for the near term SMRs, and an analysis of their deployment potential. It also highlights the safety features and licensing issues of such reactors.

Figure E.1. Currently available and advanced SMRs

ABv,

VBER-300,

AHWR

SMR that could become available for

commercial deployment before 2020

The SMR concept has been considered since the early days of nuclear power. Historically, all early reactors were smaller in size compared to those deployed today. However, the general trend has always been toward larger unit sizes (with lower specific costs due to the economy of scale), resulting in nuclear power plants with reactors of 1 000-1 600 MWe, being most commonly commercialised today.

However, starting from the mid-1980s, a new set of requirements has motivated, in some countries, the development of intentionally smaller reactors aimed at niche markets that cannot

accommodate large nuclear power plants (NPPs). Slow progress over the past two decades has resulted in about a dozen new SMR concepts reaching advanced design stages (see Table E.1), with one plant (a barge-mounted co-generation plant with two ice-breaker type KLT-40S reactors) currently under construction in the Russian Federation, three more are in a formal licensing process in Argentina, China, and the Republic of Korea, and several others being under pre-licensing negotiations in the United States and India.

At a fundamental level, plants with SMRs are not different from those with large reactors.

However there is a need to consider SMRs separately because of the:

• Higher degree of innovation implemented in their designs; and

• Specific conditions and requirements of target markets.

Today, SMRs target two general classes of applications:

• Niche applications in remote or isolated areas where large generating capacities are not needed, electrical grids are poorly developed or absent, and where non-electrical products (such as heat or desalinated water) are as important as the electricity.

• Traditional deployment in direct competition with large NPPs. As we shall see, the upfront capital investment for one unit of a SMR is significantly smaller than for a large reactor. Thus there is more flexibility in incremental capacity increases, resulting in smaller financial risks, making such reactors potentially attractive to investors and for countries initiating a nuclear programme.