MSR Benefits

Molten Salt Reactor Advantages

  • Molten Fuel - Fuel circulates through the reactor, fission products get removed, for over 99% fuel use (vs. LWR ~3%). No long-term radioactive waste.
  • Salt Cooled - Coolant far below boiling point, reactor operates at atmospheric pressure. Fuel dissolved in stable salt (no water), no loss of coolant accident possible. No need for high-pressure safety systems.
  • High Inherent Safety - No water, no high pressure, nothing that could propel radioactive materials into the environment. Thermal expansion/contraction of molten fuel salt strongly regulates fission rate; MSR is a very stable reactor. Simple safety systems work even if no electricity or operators.
  • Easy Construction and Siting - Low pressure operation, so no high-pressure safety systems. No water, so no steam containment building. Reactor factory assembled, with modern quality control, sensors and communication.
  • Lower Cost - Even with exotic materials, construction costs will be dramatically lower than LWR — factory construction, minimal manual on-site preparation. No long-term radioactive waste, so no long-term storage.
  • High Temperature Operation - Heat to generate electricity, desalinate water, produce CO2-neutral vehicle fuel, etc.
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George and I were swapping emails about liquid fuel in Molten Salt Reactors. He suggested I post this, so here goes:

As I see it, liquid fuel is the key, and not an indirect safety feature.

When solid fuel heats up, it comes together (corium) and gets even hotter. Corium quickly reaches 2800°C, hot enough to eventually melt through any reactor vessel, unless it is cooled by emergency measures.

But liquid fuel will never get that hot, because it expands and cools, or melts the freeze plug and drains and cools, or expands and bursts a pipe or a seam and spills out and cools. Any of these events would prevent the fuel from ever getting hot enough to melt the reactor. It would drain out, before the reactor vessel got anywhere close to melting.

The only way I can see liquid fuel melting an MSR is if the designers built a burst-proof, drain-proof reactor vessel without a freeze plug. And there would be no rational reason for doing so. On the contrary, MSRs would be designed to burst and drain in case of damage or sabotage. Not doing so would be like building a car without any brakes. It just wouldn’t make sense.

The problem with solid fuel is that it can’t get away from itself and cool off. That’s the fatal flaw in every solid fuel design, and that’s what all the safety features and cooling systems and redundancy is there to contend with.

Liquid fuel can get away from itself, and cool off naturally. That’s the beauty and genius of liquid fuel. In my opinion, Weinberg, Wigner, and their colleagues should have been awarded the Nobel Prize for this alone. It’s that big of a deal. It changes everything.

Because of this inherent safety feature (heat = expansion = cooling), I would contend that the liquidity of the fuel is a primary, and not a secondary, safety feature.

It’s the non-killer app of MSR.

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