Because large scale production is generally more scalable and efficient. And you probably don't want dozens of "microreactors" scattered across cities.

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usrnm 2 hours ago | parent | next [-]

> Because large scale production is generally more scalable and efficient

Rooftop solar is an example of small scale decentralized energy production, maximum efficiency is not the only relevant metric.

> And you probably don't want dozens of "microreactors" scattered across cities

Why not? If they're considered safe and pass all inspections, what's the problem?

	▲	sfn42 an hour ago \| parent [-]
		A nuclear reactor is generally treated as a high security facility. I don't know how this new reactor works but I thought it was safe to assume something like a terrorist attack on one might be bad. It's also a lot more work to inspect and control them when scattered. Rooftop solar does not have these issues.

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IsTom 2 hours ago | parent | prev | next [-]

On the other hand you can scale production of reactor themselves. And I don't think the idea is to scatter them around, but to have a power plant with dozens of them in one place (instead of 3-4 regular reactors in a regular nuke power plant).

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seanhunter an hour ago | parent | prev | next [-]

I think that may be exactly wrong. The small scale may make it easier for a reactor to be “walk away safe” ie shut itself down absent external activity. I know that is a design goal of some of the Chinese micro reactors and those are used for civilian power generation.

Secondly although generating large amounts of power is more efficient in terms of generation, generating power close to the point of use is significantly more efficient in terms of power loss on the grid as I understand it.

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roenxi an hour ago | parent | prev [-]

Large scale production of commodity goods is generally more efficient. Which is why microreactors don't seem to have any inherent disadvantages. The efficiencies tend to kick in with the raw number of items produced.

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pfdietz an hour ago | parent [-]

> microreactors don't seem to have any inherent disadvantages

They have diseconomies of scale. Some of the costs of a nuclear power plant scale sublinearly with power. Neutron economy is improved in a larger core. Larger turbines are more efficient than smaller turbines. It doesn't take 1000x as many operators to operate a NPP with 1000x the power output.

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roenxi 37 minutes ago | parent [-]

Is that relevant? The economics of nuclear plants doesn't have anything to do with efficiency as far as I'm aware, the fuel costs are relatively negligible. They can afford to be horribly inefficient if they can get economies of scale producing the plant. So you can use inefficient turbines and have bad neutron economy and it wouldn't change the economics by anything in particular.

You'd also probably find similar issues with diesel generators, but small diesel generators do roaring trade and have great commercial applications.

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pfdietz 24 minutes ago | parent [-]

Cost is not only relevant, it's paramount. Efficiency is only important insofar as it affects overall cost.

Diesel generators have the advantage of being very cheap -- an order of magnitude cheaper than NPPs per unit power output -- and of having much of their total cost being fuel cost, so they can operate at lower capacity factor. But even so, we don't see large power plants composed of arrays of diesel microgenerators.

(The solution for current higher capacity factor diesel users, like say remote operation at mines, would be to supplement them with renewables and storage to reduce fuel costs. This is already happening.)

A significant problem with any small power plant is fixed costs. A 1 MW(e) plant (Antares is said to be between 100 kW(e) and 1 MW(e)) making power at 90% capacity factor and selling at $0.05/kWh will gross about $400K/year. A single full time employee, like a security guard, will cost a good chunk of that.

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roenxi 13 minutes ago | parent [-]

> Cost is not only relevant, it's paramount. Efficiency is only important insofar as it affects overall cost.

Oh sorry, I thought you were talking about efficiency. Ok, what is the cost is for these plants?

> A single full time employee, like a security guard, will cost a good chunk of that.

I dunno, a 1MW nuclear plant could end up being pretty small. It might easily be economic to install them places that already have security guards.

	▲	pfdietz 7 minutes ago \| parent [-]
		Microreactors have been tried before by the military, for use at bases, which have guards. They not only didn't make sense to install, they didn't make sense to continue to operate once installed.