MoltexFLEX is a British nuclear energy company developing small modular

molten salt reactor A molten-salt reactor (MSR) is a class of nuclear fission reactor in which the primary nuclear reactor coolant and/or the fuel is a mixture of molten salt with a fissile material. Two research MSRs operated in the United States in the mid-20th ...

s. Their reactor designs, termed "FLEX reactors", are

stable salt reactor The stable salt reactor (SSR) is a nuclear reactor design under development by Moltex Energy Canada Inc. and its subsidiary Moltex Energy USA LLC, based in Canada, the United States, and the United Kingdom, as well as MoltexFLEX, Ltd., MoltexFLEX ...

s, and feature a hybrid approach whereby fuel assemblies similar to current

light water reactors The light-water reactor (LWR) is a type of thermal-neutron reactor that uses normal water, as opposed to heavy water, as both its coolant and neutron moderator; furthermore a solid form of fissile elements is used as fuel. Thermal-neutron reacto ...

containing the liquid salt fuel mixture are submerged in a pool of liquid salt coolant.

History

MoltexFLEX, Ltd. was launched in 2022 to develop "flexibly-operated" molten salt reactors in the UK. The company is a subsidiary of Moltex Energy Limited, which was created in 2014 to develop stable salt reactor technologies. MoltexFLEX has a laboratory in

Warrington Warrington () is an industrial town in the Borough of Warrington, borough of the same name in Cheshire, England. The town sits on the banks of the River Mersey and was Historic counties of England, historically part of Lancashire. It is east o ...

Cheshire Cheshire ( ) is a Ceremonial counties of England, ceremonial county in North West England. It is bordered by Merseyside to the north-west, Greater Manchester to the north-east, Derbyshire to the east, Staffordshire to the south-east, and Shrop ...

The FLEX reactor

MoltexFLEX's proposed product, the FLEX reactor, operates in the thermal spectrum and uses low enriched

uranium Uranium is a chemical element; it has chemical symbol, symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Ura ...

. Stable salt reactors fundamentally differ from other

molten salt Molten salt is salt which is solid at standard temperature and pressure but liquified due to elevated temperature. A salt that is liquid even at standard temperature and pressure is usually called a room-temperature ionic liquid, and molten salts ...

reactor designs in that the

radioactive Radioactive decay (also known as nuclear decay, radioactivity, radioactive disintegration, or nuclear disintegration) is the process by which an unstable atomic nucleus loses energy by radiation. A material containing unstable nuclei is conside ...

fuel salt is confined within fuel tube assemblies similar to those found in conventional

light-water reactor The light-water reactor (LWR) is a type of thermal-neutron reactor that uses normal water, as opposed to heavy water, as both its coolant and neutron moderator; furthermore a solid form of fissile elements is used as fuel. Thermal-neutron reacto ...

s. A separate, non-radioactive molten salt transfers the heat from the reactor core to

heat exchanger A heat exchanger is a system used to transfer heat between a source and a working fluid. Heat exchangers are used in both cooling and heating processes. The fluids may be separated by a solid wall to prevent mixing or they may be in direct contac ...

s. The stable salt reactor design requires no moving parts. The cooling salt circulates through the core using natural

convection Convection is single or Multiphase flow, multiphase fluid flow that occurs Spontaneous process, spontaneously through the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoy ...

, greatly simplifying the design. The FLEX reactor was originally designed to output 40 MWt, equivalent to 16 MWe, but this was later revised to be upwards of 60 MWt / 24 MWe. Each reactor unit is stated to be roughly the size of a three-bedroom house. MoltexFLEX claims the reactors can be used singly or combined in arrays. Used in combination with the company's GridReserve molten salt thermal storage system, large arrays could be used to provide baseload or peaking power at an estimated cost of £40/MWe. The company states that a 500MWe plant employing 32 FLEX reactors could be constructed in approximately 24 months. MoltexFLEX intends FLEX reactors to complement intermittent generation from renewables such as wind and solar power. Additionally, the FLEX reactor will generate heat at 750 °C, which is intended to be used in several downstream decarbonisation applications. These include:

high-temperature electrolysis High-temperature electrolysis (also HTE or steam electrolysis, or HTSE) is a technology for producing hydrogen from water at high temperatures or other products, such as iron or carbon nanomaterials, as higher energy lowers needed electricity to ...

to efficiently produce

hydrogen Hydrogen is a chemical element; it has chemical symbol, symbol H and atomic number 1. It is the lightest and abundance of the chemical elements, most abundant chemical element in the universe, constituting about 75% of all baryon, normal matter ...

for use in industry or

fuel cell A fuel cell is an electrochemical cell that converts the chemical energy of a fuel (often hydrogen fuel, hydrogen) and an oxidizing agent (often oxygen) into electricity through a pair of redox reactions. Fuel cells are different from most bat ...

s for heavy transport, desalination, and process heat for industry. Similar to other small modular designs, components of the FLEX reactor are intended to be factory-produced and readily transportable to reduce on-site work, thereby increasing speed of construction and minimising overall costs. The company claims the physics of the molten salt ensure passive safety, and that FLEX reactors do not require redundant, active safety systems. The FLEX reactor is designed to operate at atmospheric pressures, and therefore the large and expensive

concrete Concrete is a composite material composed of aggregate bound together with a fluid cement that cures to a solid over time. It is the second-most-used substance (after water), the most–widely used building material, and the most-manufactur ...

and

steel Steel is an alloy of iron and carbon that demonstrates improved mechanical properties compared to the pure form of iron. Due to steel's high Young's modulus, elastic modulus, Yield (engineering), yield strength, Fracture, fracture strength a ...

containment structures inherent in conventional nuclear plants are deemed unnecessary. Time between refuelling is claimed to be approximately 5 years, with a plant lifetime of 60 years.

Research and development

MoltexFLEX states it intends to use as many already-available components and materials as possible, with the turbine island using technology that is standard within the electricity generation industry. The company aims to have a first-of-its-kind prototype in operation by 2029. A research initiative with the

University of Manchester The University of Manchester is a public university, public research university in Manchester, England. The main campus is south of Manchester city centre, Manchester City Centre on Wilmslow Road, Oxford Road. The University of Manchester is c ...

to examine the behaviour of standard industrial-grade

graphite Graphite () is a Crystallinity, crystalline allotrope (form) of the element carbon. It consists of many stacked Layered materials, layers of graphene, typically in excess of hundreds of layers. Graphite occurs naturally and is the most stable ...

for neutron moderation was announced in early 2023. The company was awarded a £1.2 million grant from the UK Nuclear Fuel Fund in July 2023 to build and operate rigs for the development of molten salt fuel. The company also signed a Memorandum of Understanding with

Emirates Nuclear Energy Corporation The Emirates Nuclear Energy Company (ENEC, مؤسسة الإمارات للطاقة النووية) is the entity responsible for the deployment and ownership of Nuclear power plant, nuclear energy plants in the United Arab Emirates (UAE). ENEC w ...

in December 2023 to examine the commercial viability of deploying FLEX reactors in the

United Arab Emirates The United Arab Emirates (UAE), or simply the Emirates, is a country in West Asia, in the Middle East, at the eastern end of the Arabian Peninsula. It is a Federal monarchy, federal elective monarchy made up of Emirates of the United Arab E ...

External links

Official website

YouTube

References

{{reflist Nuclear energy in the United Kingdom Nuclear energy companies