m-MSR Technology.

Marine Molten Salt Reactors (m-MSRs) are like atomic battery packs.

These unique machines use a fluid fuel in the form of very hot fluoride or chloride salt infused with a ‘hot’ fissile material, instead of solid fuel rods which are used in conventional pressurised nuclear reactors (PWRs).

m-MSRs have no moving parts, operate at very high temperatures under only ambient pressure, and can be made small enough to provide ‘micro-grid-scale’ electric power for energy hungry assets, like large ships. Because of this, they can be mass-manufactured to bring the cost of energy down below that of gas, diesel and even renewables. m-MSRs are a truly radical departure from the conventional atomic energy technology we know today and the technology that opens the door to a ‘second atomic era’, reversing climate change.

There are several molten salt reactor designs being proposed, but we generally divide them into two categories:

‘Fast-spectrum’ reactors, which are best operated with chloride salts.
‘Thermal-spectrum’ reactors, which are best operated with fluoride salts.

Fluoride reactors don’t necessarily have to be thermal spectrum, but usually they are, using graphite as a moderator to slow down the high-energy neutrons of fission.

Chloride reactors don’t have to be fast spectrum, but they usually are intended to be. Hence, fluoride in general implies thermal spectrum and chloride in general implies fast spectrum.

Fluoride reactors would be ideally suited to run a Thorium fuel cycle (Th232/U233), whilst Chloride reactors are best run using the Uranium fuel cycle (U235-8).

Either way, they can provide ample, sustainable and safe electric power for ships over a lifespan up to 30 years onboard with no refuelling and no realistic proliferation concerns.

Using liquid fuel at ambient pressure, negates the need for a pressure containment vessel, like those needed for a nuclear pressurized water reactor (PWR). An m-MSR cannot meltdown and cause a hydrogen explosion. Since the system pressure is so low and the heat capacity is so high, the surrounding structure can therefore be much smaller and thinner, making it both safe and economical.

That’s a unique new advantage in atomic energy.

In an m-MSR the salt, whether fluoride or a chloride, acts as both the coolant and the fuel. The ‘fissile fuel’ is infused into the salts so that the liquid fuel salt becomes both the fuel which produces the heat, and the coolant which transports the heat to the power conversion system to make electricity.

The operating temperature of an m-MSR is between 600-900°C. That makes the m-MSR an extremely efficient power-pack. Heat is then removed from the core of the m-MSR via heat exchangers which feed that powerful heat into high power gas-turbines which in turn generate electric power.

The Chloride or Fluoride salts used in the reactor core become molten (liquid) at around 400 °C and have a boiling point at around 1400°C, giving it a vast thermal operating range.

As the fuel-coolant salt heats up, it expands and becomes less reactive until it loses reactivity and cools down. Overheating is therefore not possible. As the fuel-coolant salt cools it contracts and becomes more reactive, heating up which avoids freezing of the fuel (below 400°C).

The fuel salts have a very low viscosity, like water, and are impervious to radiation damage. The salts are chemically stable and do not change or alter their chemical state even after years of use in the fuel.

This stability is exceptional and unique.

m-MSRs emit no pollution and are powerful sources of local electricity production for large ships. These can be fast and efficient with minimal impact on both the marine environment and the ports in which they call.

The most important aspect of any atomic machine is safety. The m-MSR has excellent safety characteristics.

Atomic reactors produce heat.

Therefore, the coolant is key to avoiding accidents by overheating. At Fukushima and Chernobyl the coolant was lost and the reactor melted, causing an explosion which spread radiation.

The m-MSR is inherently walk-away safe.

In an m-MSR the fuel is the coolant, and the coolant is the fuel, so coolant cannot be lost.

This is the very definition of walk-away safety.

What happened at Fukushima and Chernobyl are unthinkable with an m-MSR.

If something does go wrong in an m-MSR and the temperature starts going up, a freeze plug will melt, pouring the entire load of liquid core fuel into sub-critical drain tanks that are intimately linked to an ultimate heat sink, keeping them cool.

This is an accident mitigation feature that is possible only in fluid fuel reactors.