News for hackers. Stuff that matters.
Re:Energy Department teams up with Bill Gates to move mini-n... by baybal2 on Sunday August 26, 2018 @05:22AM (#17845056)
I myself is against idea of small scale nuclear. Economics is not of its side. Every single nuclear facility is has a lot of fixed expenses to keep it running. Think of the amount of qualified cadres needed to run it: every nuclear power station is effectively a small science institute on its own.

Multi-gigawatt facilities are the ones where nuclear has biggest the payout.

The few nuclear power stations that are being completed these days are single reactor designs and effectively experimental plants. This is why digits on economics got unfavourable recently.

Fuel costs are negligible in comparison to every other operating expenses. This way, simple PWRs and BWRs on multi-gigawatt scales are the only designs making sense economically. Next gen CANDUs make great sense for fuel economy (and economic costs of refuelling), but even then, frequent refuelling needs are not as dramatic as the higher costs of CANDUs. Heavy water price has only been going up - and even something like an international initiative to setup a global heavy water "bank" will help little.

4th Generation reactors - the first few reactors are assuredly can't run at profit. Their sole purpose are to be research facilities. Any nation constructing them should have full realisation that constructing gen 4 only servers the purpose of advancing its science and industrial competence, not and making money in any immediate future.

Re:Energy Department teams up with Bill Gates to move mini-n... by acidburnNSA on Sunday August 26, 2018 @09:24AM (#17845825)
I used to feel this way: that large nukes are the answer because they provide megacity-scale energy for an increasingly urban world. But as I've studied the nuclear industry a few things have eroded away at this belief.

First, iteration. You can iterate on the design and supply chain of a small niche nuclear reactor much faster than a large baseload one. And you can do so without bankrupting the likes of Westinghouse or Areva. Once you figure out a new design at small scale, you can scale up. We did with with the current reactor designs and we should do it again for the newer fancy ones. I think this is what Oklo and similar reactor companies are planning on.

Second, and more novel, is that you can imagine large-scale nuclear farms of small reactors. Build small reactors that are sized to handle their own decay heat without fancy safety systems and manufacture them in a factory. Put them out there on shared security infrastructure and siting. There's more energy produced from internal combustion engines than all baseload plants in China, for instance. "You want scale? I'll give you scale!"

And finally if you still need to go big, there's also the potential of large modular reactors. If you build huge power plants in shipyards on floating platforms you can get economies of scale AND economies of mass production, while improving safety by being intimately coupled to the ultimate heat sink: the ocean. Wild idea politically but technically very intriguing. Would require much more remote operation than current plants because a crew of nuclear rough necks would have high salaries. But totally doable, and could probably decarbonize the world very rapidly.

Re:Energy Department teams up with Bill Gates to move mini-n... by JumpCrisscross on Sunday August 26, 2018 @05:41AM (#17845113)
> Every single nuclear facility is has a lot of fixed expenses to keep it running

Counterintuitively, economies of scale are more frequently found in small products which can be mass manufactured than big projects which must be custom built. This isn't an ironclad law. But neither is "nuclear must be big."

> the first few reactors are assuredly can't run at profit

"Assuredly" based on what? This article is about a commercial reactor project. One of many. Their investors have less of an interest in "advancing [their nations'] science and industrial competence" than in turning a profit.

Re:Energy Department teams up with Bill Gates to move mini-n... by baybal2 on Sunday August 26, 2018 @06:46AM (#17845282)
>Counterintuitively, economies of scale are more frequently found in small products which can be mass manufactured than big projects which must be custom built. This isn't an ironclad law. But neither is "nuclear must be big."

Nuclear power stations are not a mass manufactured product. The most pass produced ones still amount to decade long projects. There are no nuclear reactors that amount to "just add water" replicate designs, and there wouldn't be any in foreseeable future.

Just look at small coal firing powerplants, even smallest ones suitable for use in utilities are horrifically inefficient, horrifically expensive per kW/h, and still involve tons of on-site and custom engineering solutions every time. All and every vendor of "turnkey" powerplants market them as such, but just ask any power engineer if it is actually so: coal feed systems have to be optimised for type of coal used, flue solids capture systems have to be customised, foundations have to be custom engineered to accommodate heavy machinery (imagine a turbine shaft of many tonnes to get few mm bend due to soil subduction), and of course the geometry of the plant has to accommodate position of coal storage, flyash storage, transformer sites, administrative buildings and etc.

>"Assuredly" based on what?

Based to watching nation scale efforts of gen 4 reactor commercialisation failing every time. All of them wanted money from day one, and all were sure that "this time we got it right."

>Their investors have less of an interest in "advancing [their nations'] science and industrial competence" than in turning a profit.

Given the known level of intellectual ability of a successful finance professional (aka "Pro Investor") in a Western country, this doesn't surprise me at all.

Re:Energy Department teams up with Bill Gates to move mini-n... by JumpCrisscross on Sunday August 26, 2018 @06:53AM (#17845308)
> Nuclear power stations are not a mass manufactured product. The most pass produced ones still amount to decade long projects

You're arguing a car is impossible because horses only run so fast. Coal is a bad model for nukes because coal has a low power density per unit of fuel. You have to burn lots of fuel to get a meaningful amount of power, and burning lots of fuel takes lots of space. You naturally get a large plant.

There is no similar fundamental restriction on the size of a nuclear reactor. RTGs, for example, are tiny (albeit inefficient) nuclear reactors [1]. Here we have commercial efforts to miniaturise nuclear power plants so they can be mass manufactured.

"Past projects were X so it will always be X" doesn't make sense in a barely-explored and novel technological domain.

> the level of intellectual ability of a successful finance professional (aka "Pro Investor") in a Western country

"Pro investors" (which I take to mean generic fund managers) aren't backing nuclear start-ups. VCs with domain expertise, laboratories, engineers and utilities (together with the public sector) are.

[1] https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_ge...

Re:Energy Department teams up with Bill Gates to move mini-n... by baybal2 on Sunday August 26, 2018 @09:32AM (#17845848)
>"Past projects were X so it will always be X" doesn't make sense in a barely-explored and novel technological domain.

Nuclear engineering is by far not a barely-explored and novel technological domain, but an industry with near 70 year history with extremely high barriers to entry.

For you, it should be reasonable to believe that engineers and physicists with multiple postdocs, people of far greater intellectual achievements that you, me, and probably most of this website's demographic, were banging their heads non-stop for the last 70 years on the problem of making nuclear power stations economical. Nothing what came from years of their work indicate that anything but big and simple PWRs and BWRs makes sense economically.

It took decades to shave everything that can be shaved off the construction of gen 3 plus reactors to arrive at their current designs. Anything that will be employed in a design claiming bigger efficiencies has to be using less than a bare minimum used by them and that's not a lot:

- Nuclear safe superalloys - check

- Large scale forging - check

- Refueling infrastructure - check

- No mechanisation beyond control rods and pumps - check

- Advanced sensing - check

- Fuel assemblies - ridiculously cheap in relation to everything else

- On-line chemical filtration and corrosion control - check

- Steam power plant - check

Really, the only opening for lower costs are reduction in operation expenses - less scientists on site, less consumables, less or not manual labour intensive servicing, less frequent and cheaper refuelling. Besides refuelling costs, that's not a lot.

Re:Energy Department teams up with Bill Gates to move mini-n... by JumpCrisscross on Sunday August 26, 2018 @09:51AM (#17845925)
> it took decades to shave everything that can be shaved off the construction of gen 3 plus reactors to arrive at their current designs

One of the game changers are new superconductors. These are smaller, lighter and cheaper than anything we've had before. They're a very recent product of American and European colliders. Their use is common across many compact designs.

> Anything that will be employed in a design claiming bigger efficiencies has to be using less than a bare minimum used by them

Not necessarily. For example, a low-efficiency design that is simple to mass manufacture could be cheaper to build and operate than an expensive, efficient design.

Furthermore, for each element you list as being necessary there are designs which do without them. For example, Tri-Alpha uses direct energy capture (no steam power plant). Several companies eschew refueling in favor of capsulation. Large-scale forging is an odd thing to list when we're talking about minitiarrisation. Et cetera.

A small amount of research would show many arguments you present as established fact to be untrue or unfounded.

Re:Energy Department teams up with Bill Gates to move mini-n... by pfdietz on Monday August 27, 2018 @06:01PM (#17854934)
At least two of those points can arguably be greatly improved or avoided in MSRs. Since the reactor is not pressurized in an MSR, no large heavy forged pressure vessel is needed. And the steam cycle of a MSR can operate with supercritical steam w. reheat, like a conventional fossil plant's steam cycle, reducing the mass flow needed by as much as as factor of two.

The other big savings for an MSR is a very large reduction in the size of the containment building. This is because there isn't water in there that would turn to large volumes of steam during an accident and that would have to be contained by a large pressure-bearing structure. Moltex claims their containment would be a factor of five smaller per unit of power output, compared to a LWR. This would be a huge cost advantage.