Research & Development

UK / MoltexFLEX ‘Significantly Refines’ Design Of Molten Salt Reactor

By David Dalton
12 September 2023

Company aiming to build ‘first-of-a-kind’ nuclear plant

MoltexFLEX ‘Significantly Refines’ Design Of Molten Salt Reactor
Roughly the size of a two-storied house, each reactor has the potential to power 40,000 homes. Courtesy MoltexFLEX.

UK-based advanced nuclear energy developer MoltexFLEX announced it has “significantly refined” the design of its Flex molten salt reactor – delivering a 50% boost in power output, while maintaining previous targets for overnight capital cost and cost per MWh.

The company said that despite the recent increases in commodity prices around the world, the Flex reactor is still able to generate electricity for less than £30/MWh (€34, $37) when used as a source of baseload power.

MoltexFLEX did not give details of how the £30/MWh cost was calculated. The International Energy Agency has put the levelised cost of electricity* for the construction of new nuclear power plants in a range from $40 to $100/MWh.

“We have firmly established the core aspects of the Flex concept as we ramp up engineering design,” said MoltexFLEX head of engineering Chris Hankinson.

“More work will be undertaken over the coming months to further refine and finally freeze the design, and this will then be taken forward to create our first-of-a-kind reactor.”

The main changes to the Flex design include an increase in power output from 40MWth/16MWe to 60MWth/24MWe. This has been made possible by optimisation of the core design and the fuel pin material.

While the underlying technology of MoltexFLEX’s reactor remains essentially unchanged, these design evolutions represent significant improvements, the company said. The work provides more certainty about the company’s ability to deliver on its cost targets, reinforces the underpinning science, and “sets MoltexFLEX on the road towards delivering its prototype Flex reactor around the turn of the decade”.

The refuelling schedule has also been adjusted to account for the fact that the Flex reactor will now use 5% low-enriched uranium (LEU) instead of 6% LEU. MoltexFLEX said this will increase the reactor’s global deployability and harness the existing fuel supply chain.

MoltexFLEX, based in Warrington, northern England, is a subsidiary of Canada-based Moltex Energy.

MoltexFLEX said its reactor uses a patented system with two molten salts: one acting as a fuel, the other circulating as a coolant. This allows the reactor’s heat to be extracted through natural convection, without the need for pumps.

Roughly the size of a two-storied house, each reactor has the potential to power 40,000 homes. The heat produced by the reactor could be used for water desalination and more efficient hydrogen production.

* The levelised cost of electricity, or LCOE, captures both capital and operating costs that need to be covered. It is essentially the long-term price at which the electricity produced by a power plant will have to be sold at for the investor to cover all their costs.

Pen Use this content