Nuclear energy developer MoltexFLEX has reached what it calls a watershed in the development of its small modular FLEX reactor that is expected to see the UK-based company move to the next level, from the pre-concept science phase into accelerated product and project delivery.

In doing so, the company expects to expand its operations and has significantly refined the design of its FLEX molten salt reactor – delivering a 50% increase in power output, while maintaining previous targets for overnight capital cost and cost per MWh.

Despite the recent increases in commodity prices around the world, the FLEX reactor is claimed to be able to generate electricity for less than £30/MWh when used as a source of baseload power.

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 current work programme sets MoltexFLEX on the road toward delivering its prototype FLEX reactor around the turn of the decade. The main changes to the design include an increase in power output from 40MWth/16MWe as originally envisaged to 60MWth/24MWe, made possible by optimisation of the core design and the fuel pin material.

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

MoltexFLEX CEO David Landon commented: “The work we have completed further boosts our confidence in the design and economics of the FLEX reactor, and our ability to deliver a first reactor ready for global roll-out through the 2030s.”

Image: Cutaway of the FLEX reactor building