Nuclear fission fuel is inexhaustible (2022) • Hacker News Board

Re: Nuclear fission fuel is inexhaustible (2022)

#141

Post by ben_w » Sun, Jul 16, 2023, 5:17 PM UTC

SigmundA wrote: post #72

baybal2 wrote: post #47

Earlier quoted context omitted.

And important note that relatively modern coal and gas powerplants are more thermally efficient than nuclear. Nuclear is ran in between 250C-350C, which is rather inefficient, and requires very big turbines.

Nuclear does not emit carbon when used, the waste heat means very little, emissions are what matters when discussing efficiency. Plutonium 239 is also 83,610,000 MJ/kg vs coal at 35 MJ/kg so the difference in thermal efficiency is nearly meaningless given how much specific energy density advantage nuclear has.

The energy mass density is hugely relevant for spacecraft, not that important for most power stations.

(Although an old piece of anti-nuclear rhetoric that annoys me was asking if you'd prefer a bucket of coal or bucket of nuclear waste under your bed, and one half of my annoyance was indeed the relative energy densities…)

Re: Nuclear fission fuel is inexhaustible (2022)

#142

Post by Zigurd » Sun, Jul 16, 2023, 5:21 PM UTC

elsonrodriguez wrote: post #105

ponorin wrote: post #70

Earlier quoted context omitted.

the exclusion zone of fukushima hasn't changed since the beginning even after 10+ years. same for pripyat and chernobyl, those already close to 40 years. UK had to test sheep for radioactivity in certain domestic areas up until 2012. nuclear damages aren't just dead humans. they come in the forms of lost lands and untrustable food source.

I’d wager the amount of livable and arable land we’ll lose due to continued fossil fuel usage would be greater than having a Fukushima every year.

This is an interesting argument and let's stipulate it is correct. In that case, take all the oil capex and spend it on power sources that are least costly, least risky, and come on line fastest. Who thinks nuclear is least costly, least risky, and arrives soonest? Anyone? Bueller?

Re: Nuclear fission fuel is inexhaustible (2022)

#143

Post by Zigurd » Sun, Jul 16, 2023, 5:25 PM UTC

ttfkam wrote: post #89

oneshtein wrote: post #65

Earlier quoted context omitted.

Worst case is a continent wide Red Forest.

Chernobyl was a perfect storm of bad design, political corruption, and reckless behavior. No Western nuclear plant has ever run without a containment dome, has excluded basic plant design info from its operators, or put in incentives to run a reckless spin down experiment while also cutting all cooling and raising all control rods. Three Mile Island was close to worst possible in a Western design, and those aspects t…

Renewables capex already outstrips fossil fuels. Complete that transition and get all the power we need for less money, sooner, and you can buy private insurance at low rates to cover any risks.

Re: Nuclear fission fuel is inexhaustible (2022)

#144

Post by skissane » Sun, Jul 16, 2023, 5:27 PM UTC

> Many different units are used to discuss large quantities of energy. The graph above uses “quads”, or quadrillion (10^15) British Thermal Units. The SI unit of energy is the joule, and a comparable quantity is the exajoule (EJ),

Why use “quads” instead of exajoules? I really don’t understand the use of non-SI units in cases like this, it seems like pointless obscurantism. Using something like terawatt-hours, well that isn’t SI (although it is based on SI), but I can at least see the point to it. But “quadrillion BTUs” and calling that “quads” doesn’t seem to serve any useful purpose

Re: Nuclear fission fuel is inexhaustible (2022)

#145

Post by abecedarius » Sun, Jul 16, 2023, 5:27 PM UTC

gs17 wrote: post #126

abecedarius wrote: post #79

Earlier quoted context omitted.

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

I forgot what that term meant, and was imagining carefully swapping the sun with a different, younger, star.

When I first saw it in Great Mambo Chicken and the Transhuman Condition, it followed with the quote "You need to take good care of your star or it gets all dark and icky." I suspect it was parodying some ad that must've gone like "...good care of your hair..."

Re: Nuclear fission fuel is inexhaustible (2022)

#146

Post by VonGuard » Sun, Jul 16, 2023, 5:29 PM UTC

One thing this doesn't really address is that the way you separate plutonium from uranium is via acid. At the end of the process, you have a barrel of radioactive acid to deal with. Not nice stuff to handle. Toxic AND corrosive waste.

Re: Nuclear fission fuel is inexhaustible (2022)

#147

Post by pyrale » Sun, Jul 16, 2023, 5:33 PM UTC

hedora wrote: post #131

Gwypaas wrote: post #118

After 70 years of trying we haven't built an economic traditional nuclear reactor. Even less a breeder. It is like saying we have infinite fossil fuels because we can use renewables to create it from water and air. The interesting part of the conversation is the efficient allocation of money and people. In that conversation nuclear power never materialized.

The French managed to. I guess they have super-human engineering prowess. The trick is that they keep building the same obsolete US-based design instead of re-inventing the entire thing from scratch for each plant. Imagine how much more accessible computers would be if you could just copy the operating system from one "printed" circuit board to another, instead of hand-wiring all the transistors, then hand coding pro…

> The French managed to. I guess they have super-human engineering prowess.

As a french Engineer, I can confirm this. For work inquiries, please reach me at pyrale@oversized.ego

> The trick is that they keep building the same obsolete US-based design

In fact, we don't keep building them. The last N4 reactor was delivered in 2003. Since then, aside from the failed joint-venture with Germany that is the EPR, France essentially delivered nothing. That's not really an engineering issue so much as a political one.

Also France didn't "keep building the same reactor", and didn't build "obsolete" reactors. From the initial reactors (the CP generation) to the N4, the buildings got larger, late reactors produced 60% more energy than the original ones, and significant safety improvements were made. Safety changes were also backported on previous installations. In fact, the major reason why Framatome freed itself from the Westinghouse license is that it provided significant independent contribution to the original design.

Re: Nuclear fission fuel is inexhaustible (2022)

#148

Post by Detrytus » Sun, Jul 16, 2023, 5:37 PM UTC

effed3 wrote: post #51

All the analysis like this forget to count the cost of decommissioning the nuclear technology, reactors and fuels. Cost for end of life reactors are an order of magnitude those of contruction, and no safe definitive solution for fuel exist, both payed by -public-. The technology is not safe, a nuclear incident will span years and affect a wide area, people life, healt, and economic impact are to count in, not easy to…

Nuclear technology is safe enough, and the storage of the waste is non-issue: the amount of waste produced thorough last 80 years since we first split atom would fit in a single storage facility of the size of the football stadium. If we want to move away from fossil fuels then the nuclear is our best bet, solar and wind are just impractical toys.

Re: Nuclear fission fuel is inexhaustible (2022)

#149

Post by HPsquared » Sun, Jul 16, 2023, 5:40 PM UTC

sidewndr46 wrote: post #99

baybal2 wrote: post #47

Earlier quoted context omitted.

And important note that relatively modern coal and gas powerplants are more thermally efficient than nuclear. Nuclear is ran in between 250C-350C, which is rather inefficient, and requires very big turbines.

Isn't that a safety thing? To shutdown a natural gas plant you just close some valves feeding the facility, or at worse introduce something into the combustion path that halts combustion. Nuclear fission obviously can be moderated, but not in such a sharp and safe manner.

It can be, but the thermal cycling ages the very expensive equipment so it doesn't tend to be worth it.

Re: Nuclear fission fuel is inexhaustible (2022)

#150

Post by pyrale » Sun, Jul 16, 2023, 5:41 PM UTC

Zigurd wrote: post #135

hedora wrote: post #131

Earlier quoted context omitted.

The French managed to. I guess they have super-human engineering prowess. The trick is that they keep building the same obsolete US-based design instead of re-inventing the entire thing from scratch for each plant. Imagine how much more accessible computers would be if you could just copy the operating system from one "printed" circuit board to another, instead of hand-wiring all the transistors, then hand coding pro…

The French have discovered that they vastly underestimated end-of-life costs. And the power having been sold and used at a price that did not fund those costs, they are well and truly screwed.

> And the power having been sold and used at a price that did not fund those costs, they are well and truly screwed.

I don't know where you read that, but that's nowhere in actual reasonable sources.

Actual serious sources [1] report funding is being set aside for dismantling, which may be significantly eased by the fact that these reactor are actually going to serve for longer than expected.

[1], in french: https://www.ccomptes.fr/system/files/2020-03/20200304-rappor...