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ordered from Doosan in Korea. The COL was issued by the NRC in February 2012, and construction started in March 2013. Like V.C. Summer, the project experienced delays and cost escalations, and a change of project management after the demise of Westinghouse. Unit 3 is expected to enter operation in 2021, and unit 4 a year later.

In total, the DOE will have provided USD 12 billion in loan guarantees for the project. The Secretary of Energy confirmed in March 2019 that supporting the Vogtle project was critically important to ensure the revitalisation of the US nuclear industry, especially helping to rebuild a nuclear workforce and supply chain.

In addition to loan guarantees, the Vogtle project is benefiting from production tax credits (PTCs). Under the Energy Policy Act of 2005, up to 6 000 MW of new nuclear power was eligible for PTCs, provided commercial operation started by 2021. Congress voted to extend the measure in 2018, which was critical for the Vogtle project given the construction delays. The PTC is set at USD 0.018/kWh, for a duration of eight years, with a maximum annual payment of USD 125 million for each 1 000 MW of new nuclear capacity.

SMRs and other advanced reactors

SMRs have received significant attention in recent years, and the United States has been at the forefront of the SMR technology push. There are basically two types of SMRs, LWR and non-LWR based. Those based on LWR technology, a well-known technology, make up most of the world’s nuclear fleet. It is also the same technology that powers nuclear propulsion vessels (submarines and aircraft carriers). LWR-based SMRs are often derived from the design of those propulsion reactors, with compact integrated designs. Another class of SMRs are those based on non-LWR technology, i.e. where the coolant is either liquid metal (sodium, lead), molten salts or gas (helium in most cases). Many of the latter technologies are similar to those of the Generation IV reactors, a class of nuclear reactor technology that has been under development for the past two decades. Commercial deployment of Generation IV reactors and non-LWR-based SMRs is not expected before the 2030-40 period at the earliest. LWR-based SMRs, on the other hand, are expected to be deployed in the next decade.

Promoters of SMRs advocate that modular designs, with factory assembly and production of a large number of identical designs, could prove more cost-effective than large-scale LWRs, which benefit from economies of scale. In addition, design features of SMRs such as passive safety, reduced number of operators, and a smaller emergency planning zone around the NPP could further increase the competitiveness of such reactors, and the possibility of siting SMRs (for example, on sites that currently have coal-fired power plants). There is also the belief that SMRs can provide enhanced flexibility and resilience to the grid compared with larger reactors. This needs to be clearly evaluated: while LWRs in the United States have traditionally operated only as baseload generation, utilities have started implementing “flexible operation” for large LWRs to address the challenge of integrating large shares of variable renewables (wind, solar). In other countries (France, Germany), large NPPs have been load-following for decades. Modular reactors such as SMRs could provide increased flexibility with the ability to switch modules on and off. In terms of resilience, large NPPs have demonstrated their resilience in extreme weather conditions such as polar vortexes. But at the same time, intense heat and drought can challenge the operation of large NPPs,

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which require large quantities of water for cooling. SMRs by their reduced size would have fewer cooling requirements.

A few LWR-based SMR designs are currently under construction in the world – the Russian KLT-40s design for a floating NPP, and the Argentinian CAREM design). But the design that has received the most attention is the US NuScale reactor design, a genuinely modular concept currently under design certification review by the NRC. There are two projects in the United States that could see the construction of NuScale SMRs in the next decade.

Utah Associated Municipal Power Systems (UAMPS), which provides wholesale electricity, transmission and other energy services, on a non-profit basis, to its members (which include 52 public power utilities throughout Utah, Arizona, California, Idaho, Nevada, New Mexico and Oregon), launched the Carbon Free Power Project in 2015. As part of the project, UAMPS plans the development of a 12-module NuScale power plant at a site at the Idaho National Laboratory (INL). In December 2018, the DOE signed a memorandum of understanding with UAMPS and INL’s operator, Battelle Energy Alliance, for the use of 2 of the 12 modules. One of them will be dedicated to research on hybrid energy systems and the integration of nuclear energy with renewables; the other will be used for electricity generation, which INL will buy through a power purchase agreement.

In a separate project, Tennessee Valley Authority, a federally owned corporation that provides electricity generation to the Tennessee Valley region, is continuing its plans to site an SMR on its Clinch River Valley site, and is currently looking at the NuScale design. In April 2019, the NRC issued an early site permit for the site, where two or more SMRs could be built.

In addition to the NuScale SMR, other vendors are working on other LWR-based designs, including GE-Hitachi’s 300 MW SMR, based on its large-scale ESBWR reactor design, and a 160 MW SMR developed by Holtec.

In terms of non-LWR SMRs and other advanced reactors, there are also active developments by several companies to develop sodium-cooled, gas-cooled or molten salt-cooled advanced reactors. Terrapower (sodium-cooled and molten-salt cooled designs), X-Energy (gas-cooled modular reactor) and others, which are also actively involved in design evaluation processes in Canada, are active in this space.

Besides producing electricity, SMRs and advanced reactors can also provide non-electric products such as district heating or desalination, and for non-LWR SMRs that have higher operating temperatures, process steam, hydrogen production and energy (heat) storage. This can potentially facilitate the integration of advanced reactors in future lowcarbon systems with large shares of renewables, with nuclear reactors producing electricity and heat depending on market conditions.

Finally, another class of SMRs that is receiving attention in the Unites States is the micro-reactor (1 MW to 10 MW). Micro-reactors are being considered as possible sources of electricity for military bases or critical infrastructure and remote/island communities, to address security of supply and cybersecurity concerns. Their development is supported by both the DOE and the DOD.

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