Ultra Safe Nuclear • Hacker News Board

Re: Ultra Safe Nuclear

#261

Post by jay_kyburz » Thu, Sep 17, 2020, 11:39 PM UTC

ajross wrote: post #237

hairytrog wrote: post #156

Two interesting things to see here, of many. They are really planning the sites to be temporary compared to the solar/wind/ and other industrial power plants that have little or no plan for returning their sites to the original virgin soil. And two, they seem to use a molten salt loop like in concentrated solar to meet variable demand without changing the power level of the reactor, which you can't really do because…

And unlike a natural gas plant, it costs 3-10x what the equivalent generating capacity in renewables would cost. I come to post this Same Thing every time this discussion comes up. It's not about safety. Everyone serious understand nuclear, even current technologies, is "safe enough" to be useful to build out. Nuclear is outrageously expensive , though. And new reactor designs don't seem to be making much progress on…

Not to mention the waste which needs an armed guard almost forever, making the total cost of the energy almost infinite.

Re: Ultra Safe Nuclear

#262

Post by kolinko » Thu, Sep 17, 2020, 11:40 PM UTC

littlestymaar wrote: post #258

ajross wrote: post #237

Earlier quoted context omitted.

And unlike a natural gas plant, it costs 3-10x what the equivalent generating capacity in renewables would cost. I come to post this Same Thing every time this discussion comes up. It's not about safety. Everyone serious understand nuclear, even current technologies, is "safe enough" to be useful to build out. Nuclear is outrageously expensive , though. And new reactor designs don't seem to be making much progress on…

> the equivalent generating capacity in renewables would cost But most of the time, the “cost” of renewable is undefined, because you simply can't use it: you need the grid to compensate for the intermittent generation. No battery won't be enough unless you are in a really specific situation: - hydroelectric source available, in which case, it's a no-brainer, but most of those sites are already exploited (hydroelectr…

you missed judrogen electrolysis which comes out comparable in expense to nuclear when deployed on top of renewables, amd gives the same level of stability?

Re: Ultra Safe Nuclear

#263

Post by kolinko » Thu, Sep 17, 2020, 11:43 PM UTC

Wowfunhappy wrote: post #240

ajross wrote: post #237

Earlier quoted context omitted.

And unlike a natural gas plant, it costs 3-10x what the equivalent generating capacity in renewables would cost. I come to post this Same Thing every time this discussion comes up. It's not about safety. Everyone serious understand nuclear, even current technologies, is "safe enough" to be useful to build out. Nuclear is outrageously expensive , though. And new reactor designs don't seem to be making much progress on…

So, why did so many countries/companies originally build nuclear reactors, if the economics inherently don’t make sense? Has something changed?

renewables were 10-100x times more expensive back then

Re: Ultra Safe Nuclear

#264

Post by Dylan16807 » Thu, Sep 17, 2020, 11:45 PM UTC

hairytrog wrote: post #189

simonebrunozzi wrote: post #179

Earlier quoted context omitted.

> which you can't really do because of Xenon poisoning Can you clarify this part? You mean that channging the power level of the reactor would cause Xenon poisoning?

I highly recommend HBO's Chernobyl. Explains a lot this stuff. Basically, as a nuclear reactor operates, it is turning the Uranium into lots of other stuff. One component of this other stuff is Xenon-135, which absorbs neutrons and basically gets in the way of nuclear reactions. This is not an issue if you keep the reactor on because there are enough neutrons to keep things going and overcome the Xenon absorption. Bu…

You can't shut it off on a whim, but lots of reactors can drop to half output or one third output without much trouble. It probably doesn't make a big difference on the current grid, but if you have a significant fraction of nuclear power then the ability becomes useful. (I don't know if those mechanisms are applicable to this design.)

Re: Ultra Safe Nuclear

#265

Post by alextheparrot » Thu, Sep 17, 2020, 11:46 PM UTC

ajross wrote: post #254

nine_k wrote: post #241

Earlier quoted context omitted.

Two questions: (1) Night time. (2) Quiet time. Of course there are batteries! But factoring them in seems to increase the cost significantly. Power lines and cross-continent smart grids are fine, too — but also not free to build and operate. So a self-contained unit that does not depend on weather, does not need refueling, and includes its own energy accumulator has some appeal.

Right. So show me the balance sheet where building out reactors makes sense. Because as of right now it clearly doesn't, and the proof is that no one is building reactors but everyone is building windmills.

This is an incredibly weak argument, as most of the opposition to nuclear power even before widespread renewable deployment was political, not economic. Maybe the economics have changed with renewables, but that needs to be proved rather than can be inferred by the lack of US reactors being built.

Take Germany’s recent denuclearization, the efforts are completely political, there was no mention of balance sheet optimizations or concerns. China, India, Russia, among others are all building reactors - either we must agree they are fiscally irrational, or realize that there is an economic case to be made for nuclear power.

Re: Ultra Safe Nuclear

#266

Post by jay_kyburz » Thu, Sep 17, 2020, 11:50 PM UTC

aperrien wrote: post #176

arkitaip wrote: post #174

Earlier quoted context omitted.

> This number may sound like a lot, but it’s actually quite small. In fact, the U.S. has produced roughly 83,000 metrics tons of used fuel since the 1950s—and all of it could fit on a single football field at a depth of less than 10 yards. A football field of forever death is not a comforting mental image.

How large are those toxic fields of coal ash again?

Nobody is arguing we burn more coal. Many of us want to see and end to both coal and nukes.

Re: Ultra Safe Nuclear

#267

Post by Dylan16807 » Thu, Sep 17, 2020, 11:58 PM UTC

phamilton wrote: post #235

jacobr1 wrote: post #197

Earlier quoted context omitted.

Ah, the the molten salt loop is like a flywheel?

My read is that it's somehow the inverse of a flywheel. A flywheel means consistent output for variable input whereas this is consistent input leading to variable output. Or maybe I'm way off.

That's just one way you can use a flywheel.

A flywheel is the equivalent of a battery/capacitor. It can smooth inputs, or it can smooth outputs, or it can simply save power for later.

Re: Ultra Safe Nuclear

#268

Post by justinzollars » Fri, Sep 18, 2020, 12:03 AM UTC

I'd love to see these built in San Francisco. If we were serious about a Carbon free future we would build nuclear

Re: Ultra Safe Nuclear

#269

Post by necheffa » Fri, Sep 18, 2020, 12:04 AM UTC

littlestymaar wrote: post #248

hairytrog wrote: post #156

Two interesting things to see here, of many. They are really planning the sites to be temporary compared to the solar/wind/ and other industrial power plants that have little or no plan for returning their sites to the original virgin soil. And two, they seem to use a molten salt loop like in concentrated solar to meet variable demand without changing the power level of the reactor, which you can't really do because…

Excuse me, could you be more specific about why you think Xenon poisoning is relevant here? I think I just missed your point.

Xenon is both a fission product and a neutron absorber. So if your reactivity dips too low you won't have enough neutrons buzzing around to sustain the reaction and will have to wait for the xenon to decay before you are able to start up again.

Re: Ultra Safe Nuclear

#270

Post by nimish » Fri, Sep 18, 2020, 12:05 AM UTC

gruez wrote: post #27

nimish wrote: post #18

Safety is no longer the reason Nuclear is not worth it. The sun is a giant, free nuclear fusion plant in the sky. We can capture 1/5th of its output per square meter. For free! The wind -- caused by solar heating -- also generates free power. The cost of harvesting it is now so low, and will always continue to decline as any technology will, that any fuel-based generation mechanism is going to be rendered uneconomic…

>We can capture 1/5th of its output per square meter. For free! except you know, the solar panels. by the same logic you can you can capture fission power for free, all you need is set up the reactor.

Fission is ultra-complicated and dangerous with Uranium.

I can buy a solar panel for $100 and have it generating electricity in my backyard at a click of a button

Why would I _not_ do that?