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Comment by ortusdux | Hacker News Reader

I've done a fair amount of research into molten salt reactors, and if we can solve the containment issue they should be very cost effective. The molten salts are extremely corrosive, which cuts their lifespan down to ~5 years. Newer designs should reach 10 years and there is extensive research into designing systems that will last 20+ years.

They should be much cheaper to build and operate because they have several inherent safety features. They operate at one atmosphere, so you don't need expensive pressure containment systems. The fissile material is already melted, so meltdowns are basically impossible. Most designs have a drain line to a gravity fed safety containment vessel full of control rods. The drain line is actively cooled to solidify the salt, forming a plug that automatically melts during a power loss or over-temperature event.

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This is solving the wrong problem, and therefore will not advance nuclear. Cost is the impediment to nuclear, not any sort of safety concerns.

That molten salt reactor will need to have a negative cost in order to compete with the cost of stored renewable energy.

The future of nuclear energy must either abandon the thermal steam cycle for electricity generation, or generate massive value from the nuclear reaction part apart from generating steam.

> Cost is the impediment to nuclear, not any sort of safety concerns

That's not entirely true, and safety features and regulations are a major part of nuclear's cost.

> That molten salt reactor will need to have a negative cost in order to compete with the cost of stored renewable energy

Does stored renewable energy come for free? From what i recall, there's still no actual solution to that problem on a big scale.

>safety features and regulations are a major part of nuclear's cost.

Which regulations -that aren't there for safety- are driving up cost of nuclear power? I can't find any. Are you saying we should cut down on safety to make nuclear able to compete?

Making a molten salt reactor safe might be much cheaper than a light water reactor.

No, he is saying that MSR do not have many of those problems and are in compliance with those regulations without costly measures.

> with the cost of stored renewable energy.

Which is how much? We don't have a good way to store energy right now.

> Cost is the impediment to nuclear, not any sort of safety concerns.

Safety systems and regulations greatly inflate costs. Any reasonable, safe measures that can be taken to reduce them will make nuclear more profitable.

A good example of this is small modular reactors. Current nuclear plants need to be approved by regulators on a case by case basis. Nuscale, a SMR company, is the first to get their module design signed off by the nuclear regulatory commission. This means that they can build them at volume and skip most of the red tape.

Analysts expect Nuscale's systems to be 1/4 to 1/3 cheaper than current nuclear plants. Imagine the price reduction of a SMR with half the complexity.

Sadly NuScale's pilot project is failing to hit the required numbers. Note that political opposition was not an issue, as it's on DoE land.

I'd love to see someone crack the code, but based on everything I've read, SMR is not going to be the silver bullet in changing nuclear's garbage ROI, unlike I hoped some years ago.

I like molten-salt reactors, but they still depend on steam turbines† and cooling systems to convert the heat into useful energy. So they don't help to solve the fundamental cost problem Epistasis identified: although they might reduce the gap between high nuclear-plant cost and low coal-plant cost, but they won't cross the Rubicon to even lower solar-plant cost.

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† which operate at substantially more than one atmosphere!

Given the enourmous costs of decommissioning nuclear power plants already I fail to see how a reactor containment that lasts 10-20 years at best improves the situation.

It's interesting, the poster above was complaining that we have to put solar panels and windturbines into landfills and now you're proposing molten salt reactors with lifespans of 5-20 years (where the 20 years are still extensively researched)?

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