Jacobs to assist Moltex in development of SSR

The SSR is unlike the original US Molten Salt Reactor Experiment and its descendants, which use fuel dissolved in a molten fluoride or chloride salt, which also functions as the reactor's coolant and operates at atmospheric pressure. UK-based Moltex's design instead holds the molten fuel salt inside fuel pins very similar to those used for normal MOX fuel. Heat transfer from the outside of the fuel pin to the heat exchangers is effectuated by a second, non-fissile molten salt.

Moltex says this eliminates a range of problems associated with ‘traditional’ MSRs, which must handle a hot, highly radioactive fluid of changing chemical composition while ensuring maintainability over the lifetime of the reactor.

Moltex's SSR instead circulates a largely inert coolant salt at atmospheric pressure through the reactor - which it says is much easier to operate and maintain, with leaks presenting much lower risks - whilst having the advantages of a liquid fuel within the pins. The isotropy, even as burn-up progresses, eliminates traditional issues of solid fuel deformation and cladding breaches, as well as avoids the intense local overpressure within the solid fuel from gaseous fission products.

To assist with validation of thermal transfer modelling, Jacobs' chemistry, materials, engineering, instrumentation and modelling teams will collaborate to create a technically complex simulation to replicate the heat output of a fuel channel and to validate computational fluid dynamics modelling of the thermal transfer across the fuel assemblies into the coolant.

Moltex already uses Jacobs' ANSWERS software for radiation transport modelling and simulation of reactor performance.

"We're looking forward to continuing our support for Moltex into this new phase of development as part of our strategy to be a solutions provider at the cutting edge of research into advanced reactors," said Clive White, senior vice president of Jacobs Critical Mission Solutions International. "The Stable Salt Reactor design is significant because of its potential to recycle waste in a clean, safe and economical way, generating electricity which will power communities while reducing carbon emissions."

Moltex has been awarded more than USD6 million in funding from Advanced Research Projects Agency - Energy, a US Department of Energy agency, to help develop the SSR reactor. Moltex is part of the UK government's Advanced Modular Reactor initiative and, through collaboration with NB Power, is progressing with plans to demonstrate the first operational Stable Salt Reactor in New Brunswick, Canada.