MoltexFLEX launches flexibly-operated molten salt reactor

Thursday, 29 September 2022

"This advanced nuclear technology has the flexibility of gas-fired power stations, but it generates electricity at a lower cost, and without carbon emissions," said Warrington, UK-based MoltexFLEX.

As the reactor has no moving parts, MoltexFLEX said the FLEX reactor is simple in both design and operation. The reactor can respond to changes in energy demand - automatically entering an idle state or returning rapidly to full power - making it an ideal complement to wind and solar power. Conventional reactors, it said, are not suited to rapidly changing their output.

According to MoltexFLEX, the cost of electricity generated by the FLEX reactor is comparable to that of wind, at just GBP40 (USD44) per MWh. This is achieved through a unique, patented system which uses two molten salts: one acting as a fuel, whilst the other circulates as a coolant. This allows the heat from the reactor to be extracted through natural convection, without the need for pumps.

The FLEX reactor is small and modular, allowing components to be factory-produced and readily transportable, reducing on-site work, increasing speed of construction, and minimising overall costs. It is passively safe, so does not require engineered, redundant, active safety systems.

A cutaway of the FLEX reactor (Image: MoltexFLEX)

Once online, the FLEX reactor can be operated with the same skills and equipment used in a fossil fuel plant. The reactor has no moving parts and is fuelled for 20 years at a time, meaning that there is very little operator input and very low ongoing costs.

Each reactor delivers 40 MW of thermal energy at 700°C. This heat is stored in MoltexFLEX's GridReserve thermal storage tanks, so that the power plant can deliver three times the power when renewables alone cannot meet the market need for electricity.

During longer periods of high renewable generation, the FLEX reactor can simply move passively into idle mode - producing just enough heat to keep the reactor at operating temperature.

MoltexFLEX estimates it would take just 24 months to build a 500 MW power plant. The company plans to have its first reactor operational by 2029.

"We recognised the need for an energy supply that can support renewables when the sun doesn't shine or the wind doesn't blow," said MoltexFLEX CEO David Landon. "In the FLEX reactor, we have a solution for consumers and countries alike.

"The FLEX reactor provides the safety net of affordable domestic energy, but is versatile enough for applications ranging from decarbonising heavy industry to powering cargo ships."

The FLEX reactor is the thermal neutron (moderated) version of Moltex Energy's stable salt reactor technology. That technology is shared with MoltexFLEX's sister company, Moltex Energy Canada Inc, which is developing the fast neutron version of the stable salt reactor.

In May 2021, the Canadian Nuclear Safety Commission completed the first phase of the pre-licensing vendor design review for Moltex Energy's 300 MWe Stable Salt Reactor - Wasteburner (SSR-W 300) small modular reactor. The SSR-W is a molten salt reactor that uses nuclear waste as fuel. The company aims to deploy its first such reactor at the Point Lepreau site in New Brunswick by the early 2030s.