Why nuclear energy is our best option at the moment • Hacker News Board

Re: Why nuclear energy is our best option at the moment

#371

Post by beat » Wed, Nov 04, 2015, 3:30 PM UTC

AnimalMuppet wrote: post #250

beat wrote: post #237

Earlier quoted context omitted.

The Ivanpah plant isn't a great example. The tech is already going obsolete, and it's producing far below theoretical effectiveness. It should be able to produce a terawatt. Fundamentally, it's because solar is immature technology, and nuclear is mature. So what would the efficiency and cost be for a mature solar plant? And how do we get to maturity? If a solar plant could hit 50% of the energy efficiency on the same…

Solar Star (see adventured's comment parallel to yours) may be the current state of the art. It claims 747 MW on 3200 acres. That still doesn't put it in the same league as nuclear.

True, but does it have to be? We can throw more land at the problem. I live in the midwest, where we're starting to see the countryside dotted with windmills. If you can generate a terawatt per square mile, how many do you need?

Re: Why nuclear energy is our best option at the moment

#372

Post by beat » Wed, Nov 04, 2015, 3:32 PM UTC

adventured wrote: post #223

chc wrote: post #215

Earlier quoted context omitted.

A sibling commenter already did run the numbers on it, and found nuclear ahead by a factor of 10: https://news.ycombinator.com/item?id=10503382

I should add, that's just for the largest US plant. The Kashiwazaki-Kariwa monster in Japan, with seven reactors, was capable of producing nearly 8,000 MW on just ~1,000 acres. Or upwards of 50 to 80 times what the best utility solar installations today can produce at max output on the same amount of land. https://en.wikipedia.org/wiki/Kashiwazaki-Kariwa_Nuclear_Pow... The Solar Star installation could end up being t…

Solar star is theoretically capable of about a terawatt on about 4k acres, so that makes the reactor about 15-20 times as efficient. Still a huge difference, but don't hype the numbers too much.

Re: Why nuclear energy is our best option at the moment

#373

Post by JoeAltmaier » Wed, Nov 04, 2015, 3:35 PM UTC

acqq wrote: post #264

beat wrote: post #241

Earlier quoted context omitted.

Only thorium breeders seem feasible for commercial production. Plutonium breeders are terribly unsafe.

Do you have any link of any real development of any useful thorium reactor? If it has benefits, why isn't anybody getting rich developing it now? Even if the western politicians or corporations have any supposed agenda, why don't Russia and China develop or use them instead of scheduling the plutonium (Pu) reactors?

No question they work. Lab reactors were run for years until funding ran out. There were 5 American startups designing Thorium reactors a few years back. I'm guessing regulation killed them.

Re: Why nuclear energy is our best option at the moment

#374

Post by kuschku » Wed, Nov 04, 2015, 3:50 PM UTC

Eeko wrote: post #337

kuschku wrote: post #279

Earlier quoted context omitted.

Well, they did it because it was easy. And cheap. If you want safe nuclear power, including demolishing the reactors safely, safely getting rid of all the materials, nine nines safety, etc, then it won’t be profitable. If you want for-profit nuclear power, then either the government has to subsidize it, or it has to be unsafe. Usually, it’s both unsafe (companies save money everywhere, including stuff like not securi…

Depending on the definition of "safe". Digging a long hole to the ground, towing an old to-be-demolished barge on top of Mariana's trench etc. is not that expensive. The hard part right now is deciding on suitable ground for the tombs. Doing seismic measurements, analyzing the rock formations and especially forming the policies for burial (e.g. do we reserve the option to dig the stuff back up for use in breeders?) c…

Well...

> but it's hardly an expensive part of the process.

https://en.wikipedia.org/wiki/Asse_II_mine

> Das Gesetz zur Beschleunigung der Rückholung radioaktiver Abfälle und der Stilllegung der Schachtanlage Asse II („Lex Asse“) wurde am 28. Februar 2013 durch den Bundestag beschlossen.[70] Die Kosten werden auf vier bis sechs Milliarden Euro geschätzt.[71] Sie sollen nicht durch die Betreiber, sondern durch den Bund getragen werden.

Translation:

> The "Nuclear Waste Retrieval Speed Up and Asse II mine closing law" was passed on February 28, 2013. The costs are expected to be between four and six billion Euro. They will be paid not by the owner, but by the federal government.

Germany built one. Turns out it wasn’t that safe. Now we have to dig up all the waste again, and put it back underground into a different mine. And this mine was our only hope, actually, because it was the only semi-stable unused salt mine left in Germany.

Now the government passed a tax "Brennelementsteuer" (Nuclear Fuel Tax) that means the owners of nuclear power plants have to pay parts, approx up to 20% of the costs for demolishing the plants, and still 0% of getting rid of the waste, this money will be gotten as a tax for using nuclear fuel.

And, with this tax, nuclear energy is now, even despite getting similar subsidies as renewables, more expensive than wind. Several large energy companies already sold their nuclear plants and switched over to wind; even the few plants in Germany that were still running after Fukushima are now not profitable anymore.

Re: Why nuclear energy is our best option at the moment

#375

Post by beat » Wed, Nov 04, 2015, 4:37 PM UTC

JoeAltmaier wrote: post #373

acqq wrote: post #264

Earlier quoted context omitted.

Do you have any link of any real development of any useful thorium reactor? If it has benefits, why isn't anybody getting rich developing it now? Even if the western politicians or corporations have any supposed agenda, why don't Russia and China develop or use them instead of scheduling the plutonium (Pu) reactors?

No question they work. Lab reactors were run for years until funding ran out. There were 5 American startups designing Thorium reactors a few years back. I'm guessing regulation killed them.

People assume regulation is responsible for the death of nuclear programs all the time. More likely, it's technical feasibility or cost issues. Which gets back to the "Why isn't China doing this?" Building a lab reactor that implements a theoretical reaction chain, and building a production reactor that puts out terawatt-range power safely and cost-effectively for decades are two entirely different things. Lab reactors are the Hello World apps of nuclear power.

Re: Why nuclear energy is our best option at the moment

#376

Post by yk » Wed, Nov 04, 2015, 5:14 PM UTC

ars wrote: post #327

yk wrote: post #303

Earlier quoted context omitted.

Because burning it involves superheated, radioactive phosphoric acid.

What are you talking about? No it doesn't.

The designs I have seen dissolve the spent nuclear fuel in phosphoric acid and then operate with liquid fuel. ( Perhaps there are proposals that do not operate like that, but I think you want to homogenize the fuel as much as possible which means some kind of liquid fuel.)

Re: Why nuclear energy is our best option at the moment

#377

Post by JoeAltmaier » Wed, Nov 04, 2015, 5:20 PM UTC

beat wrote: post #375

JoeAltmaier wrote: post #373

Earlier quoted context omitted.

No question they work. Lab reactors were run for years until funding ran out. There were 5 American startups designing Thorium reactors a few years back. I'm guessing regulation killed them.

People assume regulation is responsible for the death of nuclear programs all the time. More likely, it's technical feasibility or cost issues. Which gets back to the "Why isn't China doing this?" Building a lab reactor that implements a theoretical reaction chain, and building a production reactor that puts out terawatt-range power safely and cost-effectively for decades are two entirely different things. Lab reacto…

Here's somethign a little stale. Gate's company is looking into it:

http://www.the-weinberg-foundation.org/2013/07/23/bill-gates...

Re: Why nuclear energy is our best option at the moment

#378

Post by beat » Wed, Nov 04, 2015, 5:35 PM UTC

AnimalMuppet wrote: post #250

beat wrote: post #237

Earlier quoted context omitted.

The Ivanpah plant isn't a great example. The tech is already going obsolete, and it's producing far below theoretical effectiveness. It should be able to produce a terawatt. Fundamentally, it's because solar is immature technology, and nuclear is mature. So what would the efficiency and cost be for a mature solar plant? And how do we get to maturity? If a solar plant could hit 50% of the energy efficiency on the same…

Solar Star (see adventured's comment parallel to yours) may be the current state of the art. It claims 747 MW on 3200 acres. That still doesn't put it in the same league as nuclear.

As a followup, I did some calculations and figure the US averages about 534twh of electricity - say it peaks at 1000twh, which seems reasonable. Both solar and wind appear to be capable of about 1twh per square mile these days, based on existing installations. So 1000 square miles of wind/solar, plus some battery caching, could provide 100% of our typical energy needs. This seems pretty feasible to me.

Re: Why nuclear energy is our best option at the moment

#379

Post by beat » Wed, Nov 04, 2015, 5:39 PM UTC

JoeAltmaier wrote: post #377

beat wrote: post #375

Earlier quoted context omitted.

People assume regulation is responsible for the death of nuclear programs all the time. More likely, it's technical feasibility or cost issues. Which gets back to the "Why isn't China doing this?" Building a lab reactor that implements a theoretical reaction chain, and building a production reactor that puts out terawatt-range power safely and cost-effectively for decades are two entirely different things. Lab reacto…

Here's somethign a little stale. Gate's company is looking into it: http://www.the-weinberg-foundation.org/2013/07/23/bill-gates...

I think we should definitely keep researching thorium. The theoretical aspects are very appealing and solve a lot of problems. My concern isn't that thorium can't work, or won't solve the problems it should solve, but rather that there's a LOT of handwaving and assumptions and finger-pointing from the pro-thorium crowd. If it was as easy, cheap, and safe as they claim, it'd be done already. Doesn't mean it can't be done, just that it isn't as easy or cheap as is claimed by its proponents.

Re: Why nuclear energy is our best option at the moment

#380

Post by DennisP » Wed, Nov 04, 2015, 5:58 PM UTC

neltnerb wrote: post #238

InclinedPlane wrote: post #171

Earlier quoted context omitted.

Corrosion is not a problem. But there is still a ton of work that needs to be done with molten salt reactors. But it's work we should do, I feel. I used to be skeptical of the idea but after doing a considerable amount of research I changed my opinion, the core design has a myriad of advantages and it's practically criminal we aren't dumping gobs of money into research for it. As for water, the working fluid of the h…

Wait wait wait, you're going to have to provide a citation for this claim that corrosion is not a problem. I was told by faculty with joint appointments in matsci and nuclear engineering that it is a major issue and that while they've developed some alloys that look reasonable in the recent past it's still academic research unproven in scale up. Holding molten salts is really hard... they corrode the heck out of even…

Oak Ridge ran an MSR for four years without difficulty. One solution is to just do that, rather than trying to make a reactor last 60 years.

At least two startups are going that route. ThorCon's design is a plant with reactor cores as replaceable "cans," each lasting four years in production plus four years of cool-down before shipping to a reprocessing facility. Terrestrial Energy has sealed 7-year units.