The $2.55 million ARPA-E funding was awarded through the MEITNER program, which develops enabling technologies for advanced reactor designs to bring them closer to market and make them more investable as an affordable clean energy route.

UK-based Moltex chose to develop Composite Structural Technology to reduce construction times for the Stable Salt Reactor (COST SSR) and is involved in the U.S. for the first time after previously focussing on the UK and Canada.

“We see those nations as having higher likelihood of near-term deployment but there is expertize in the U.S. that does not exist anywhere else and we see the U.S. as a huge market in the next three decades,” Rory O'Sullivan, CEO for North America Moltex Energy, told Nuclear Energy Insider.

Fleet model

Moltex aims to reduce the construction schedule to less than 36 months for the FOAK (First-Of-A-Kind), with a path for future reductions for NOAK (Nth Of A Kind). The mission is to make SSR as routine to build and qualify as a Combined Cycle Gas Turbine (CCGT) plant, which is commonly around 24 months.

“Most of the current focus for advanced reactor vendors is getting to ‘demonstration’ with a single plant, but to make the global impact Moltex is seeking, we are thinking about the fleet model: how do we get whole fleets deployed on the urgent timeframes required for climate and social change,” added O’Sullivan.

Moltex Energy was formed as recently as 2015, and in a short time has made significant progress. In December 2017 Moltex Canada Inc. commenced the CNSC (Canadian Nuclear Safety Commission) Vendor Design Review process and received government research funding in the UK for C&I development. In 2018, Moltex signed an MOU with New Brunswick Power to develop SSR-W working towards a FOAK deployment in the province. 

Simplified construction

The Moltex SSR leans heavily on existing approaches to reactor design and licensing approaches to expedite the licensing process as much as possible, a major hurdle to any advanced reactor deployment. However, that’s only half the battle; the First-Of-A-Kind then needs to be constructed, and the build time can be just as significant a hurdle.

Contemporary New Build programs are beset by construction difficulties due to incremental design changes, logistics challenges, financing large indirect costs of construction, and complex onsite processes for managing Quality Assurance. This makes them challenging to finance successfully, and with such high investment risk unwilling to be borne by the private sector, the number of New Build projects are dwindling.

COST technology allows greater versatility of standardized design site-to-site, and vastly simplifies onsite labor and quality assurance processes to achieve a comparable build quality. Plus, with the inherent safety of the SSR and lack of any high pressures in the nuclear island, radical simplifications can be made without impacting safety. 

Economic reality

“Moltex believes that to truly displace cheap fossil fuelled generation on the TW scale and satisfy an insatiable need for mass clean energy, SSR plants eventually need to be as fast to build, and cheaper in terms of electricity cost, than a CCGT or coal-fired plant, driving them out of the market by economic reality, rather than subsidy,” said O’Sullivan.

“SMRs, or any clean energy candidate for that matter, has a simple success criteria: be cheaper than everything else. Government subsidies and carbon taxes to encourage change can only ever be a short-term fix; if a technology is less profitable it cannot be sustainable, someone has to pay. That’s where SSR comes in, it wants to undercut fossil fuelled generation, truly displacing it from the market.”

O’Sullivan says that SMRs have many advantages but their small size increases costs as they lose economies of scale. The SSR, although small in size is large in power. The first design is the 300 MW reactor which can be coupled to 900 MW turbines using GridReserve to run 8 hours a day at the higher output power or scaled up to a 1000 MW reactor which could be coupled to 3000 MW turbines.

“This gives the SSR both the advantage of economies of numbers and economies of scale,” he says.

Composite opportunity

There are numerous examples of industry-ready composite construction solutions in the wider civil engineering industry, which have demonstrated the opportunity from these contemporary design methods. Given the absence of a nuclear regulatory process in alternative industries it is perhaps logical that they have been adopted in other major projects first, well before nuclear has been able to fully capitalize on the opportunity.

“Moltex is not developing ‘all-new’ solutions,” admits O’Sullivan, “rather we are assessing the available options and downselecting the most suitable method (or methods) from a shortlist of high Technology Readiness Level (TRL) candidate composite technologies.

“Purdue University, who shall conduct the concept design and selection phase, are familiar with a number of these candidate technologies currently on the market. They are well-positioned to quantify the potential efficiencies of adopting the methods for SSR.”

Changing perceptions

Advanced reactors like SSR are about more than just an evolution of current nuclear power plants; they present an opportunity for a change in the social perception of nuclear power.

O’Sullivan believes the political desire and economic potential are clear but selling the concept to the public could limit deployment.

“The COST project seeks to quantify the actual hazard arising from severe accidents in SSR plants, which have strong inherent safety features, such as absence of pressure and non-volatile chemistry,” says O’Sullivan.

“Moltex understand this is the first public project of its kind to do so, in a quantitative sense – rigorously calculating the precise sources of radioactivity that can depart the reactor under such extreme scenarios. Moltex expects to show that beyond the small site boundary, there is no perceptible impact; that’s an industry-changing claim for nuclear power.

“If we can demonstrate conclusively that a nuclear power plant accident cannot conceivably result in a greater risk to the public than any other form of power generation (alongside the fact SSR-W is a consumer of current nuclear waste), then there can be no greater social advertisement for the technology.”

Nuclear Energy Insider