Fukushima Reactor: TEPCO robot aims to extract nuclear fuel • Hacker News Board

Re: Fukushima Reactor: TEPCO robot aims to extract nuclear fuel

#241

Post by pyrale » Tue, Oct 08, 2024, 3:25 PM UTC

acdha wrote: post #203

pyrale wrote: post #185

Earlier quoted context omitted.

> So, if your fathers started coal plants, you close them, stop paying for them and can forget about them. I suspect you don't live in e.g. Tuvalu? Or in a country experiencing desertification like Spain?

You misunderstood the point: yes, burning coal is bad. The argument is that once you stop doing that, it’s over. I don’t think that’s completely true - the impact of mining and ash won’t instantly disappear - but if the question is whether we should switch from one thing which has significant environmental hazards to another which poses significant risks or alternatives which do not, that past example suggests that w…

> The argument is that once you stop doing that, it’s over.

My issue is that this statement is wrong, though. All the greenhouse gas from coal that was burned in the past, and all the coal we're still burning, will still be around and is still going to slowly bake the planet we live on for the next millenia [1].

Effectively, coal emissions are only considered this way because, after we stop producing, we stop seeing the smokestacks and we forget that the byproducts are still there. This is also true for most other pollution sources: industrial sites with heavy metal pollution don't magically clean themselves when the factory closes. WW1 battle areas are still deeply polluted and some are still unfit for agriculture. "Eternal" chemicals are never going back to the oil well. And, for us technologists, ewaste does not magically disappear [2].

It's really maddening that some people develop an acute perception that radioactive waste is "forever", but somehow fail to understand that the same is true for a very large part of the waste we create now, for which nature hasn't (over millions of years) evolved organisms able to eat them.

[1]: https://royalsociety.org/news-resources/projects/climate-cha... [2]: https://news.ycombinator.com/item?id=41765334

Re: Fukushima Reactor: TEPCO robot aims to extract nuclear fuel

#242

Post by Retric » Tue, Oct 08, 2024, 3:30 PM UTC

otherme123 wrote: post #114

portaouflop wrote: post #110

Earlier quoted context omitted.

What is the point ? That we dumped so much crap into the ocean a little more won’t hurt?

And then you have to read about how expensive nuclear is today compared with a few decades ago because of the excesive regulations. Regulations that pro-nuclear usually want to relax, to make nuclear more economically viable. No wonder that dumping nuclear waste to river and oceans is cheaper than having to safely store it for at least a couple of centuries.

Regulations don’t change the cost that much. Yes, you can save money by not having a containment vessel around your nuclear reactor but that’s a major risk which has inherent costs. On net it’s cheaper to have that containment than not irregardless of regulations.

Dig into the rising costs, and you find root causes like 3 mile island showing the industry it needed to increase maintenance spending. It wasn’t some arbitrary overreaction but simply the damage accumulated enough to cost a billion+ dollar asset. Thus much of that “increased” spending is simply asset preservation.

Re: Fukushima Reactor: TEPCO robot aims to extract nuclear fuel

#243

Post by slt2021 » Tue, Oct 08, 2024, 3:47 PM UTC

natmaka wrote: post #189

slt2021 wrote: post #51

Earlier quoted context omitted.

nuclear fuel: nuclear rods can last about 3-7 years, lets say 5 on avg. 150 rods per 1 GW reactor. so its like one or two rail cars of fuel - extremely compact footprint. how calculate yourself how much fossil fuel you need to power 1 GW power plant for half a decade, and how much CO2 emissions will you generate? How many rail cars of coal Germany will need to generate 1 GW 24/7/365 for 5 years reliably ? it is just…

It's not about energy density but availability. If a nation cannot buy uranium (scarce resources, embargo...) it loses at least temporarily its nuclear infrastructure (and gasps for energy). This is not a real concern for renewables. > Nuclear is capturing strong and weak forces Other (way more practical and determinant) parameters are less enticing. For example: it 'burns' uranium and produces dangerous waste.

>>If a nation cannot buy uranium (scarce resources, embargo...)

not an issue at all, Canada, Australia, Kazakhstan, bunch of other nations mine and sell uranium. Whenever there are big mountain ranges, there is uranium. and it is cheap as a commodity

Re: Fukushima Reactor: TEPCO robot aims to extract nuclear fuel

#244

Post by slt2021 » Tue, Oct 08, 2024, 3:48 PM UTC

natmaka wrote: post #217

Moldoteck wrote: post #212

Earlier quoted context omitted.

uranium can be stockpiled. Or like in japan/france - reprocessed & reenriched. It'll be more expensive but will cover most of temporary problems of uranium supply. For renewables - if you don't have local factories at scale and a steady supply of materials, incl for energy storage - the problem will be the same

> stockpiled Doing so may trigger a market tension. France reprocesses only part of its fuel, and only 1 time. > the problem will be the same Uh? An existing fleet of reactors is moot without uranium. An existing fleet of renewables just works (it only needs wind, sun, geothermal activity...)

Uranium supply is not an issue at all, given that plenty of nations sell it, it is not rare mineral and can be found in abundance.

and you need to replenish uranium fuel like once in 5 years - so this is not an issue at all for nuclear energy

Re: Fukushima Reactor: TEPCO robot aims to extract nuclear fuel

#245

Post by cedws » Tue, Oct 08, 2024, 3:57 PM UTC

atomic128 wrote: post #20

baq wrote: post #2

> “With the goal of completing the decommissioning in 30 to 40 years [...]" Can't decide if it's a success of nuclear or a failure. Leaning towards success: - ~900 tons of super duper radioactive material is more or less safely sitting in steel enclosures - we're (as a global civilization) slowly but surely figuring out how to move the hazardous waste to a safer storage, and it may only (ahem) take a couple generatio…

The "super duper radioactive material" you're so afraid of is what's left of the fuel. It's full of energy. The precious fuel is so full of energy that it gets hot ("decay heat"). Without cooling, it melts. Cooling was lost during the most powerful earthquake ever recorded in Japan, the fourth most powerful earthquake ever recorded anywhere. The "Great East Japan Earthquake" and its tsunami killed 19,759 people. The…

Yeah it’s all fine, it only displaced a few thousand people from their homes and made an area an uninhabitable wasteland. It’s only going to cost ~$500 billion in total for cleanup[0]. Nevermind the capital loss from the destruction of the power plant itself. Nuclear is definitely a great idea.

[0]: https://en.m.wikipedia.org/wiki/Fukushima_nuclear_accident_c...

Sarcasm aside, it's extremely frustrating when deaths are the only dimension people use to compare with other electricity sources. You can't just put on a blindfold and ignore all of the other factors. Just because only a handful of deaths can be directly attributed, doesn't mean nuclear isn't an absolute nightmare when it goes wrong.

Re: Fukushima Reactor: TEPCO robot aims to extract nuclear fuel

#246

Post by Scarblac » Tue, Oct 08, 2024, 3:59 PM UTC

heavenlyblue wrote: post #177

WalterBright wrote: post #101

Earlier quoted context omitted.

> an EV is 90% efficient An EV is 85-90% efficient with power coming out of the batteries. However, the charging efficiency of the batteries is at about 80%. So the overall efficiency is 80% of 90%, or 72%.

For the sake of replacement, we should not include the charging efficiency, because the context is that of "how kuch energy the car can store" rather than "where it comes from"

It's "how much is needed to keep doing the same thing", I don't see why charging would be excluded.

Re: Fukushima Reactor: TEPCO robot aims to extract nuclear fuel

#247

Post by rbanffy » Tue, Oct 08, 2024, 4:08 PM UTC

natmaka wrote: post #200

defrost wrote: post #170

Earlier quoted context omitted.

It's clear that a small number of mostly older people suffered unduly from the stress of an imposed evacuation. It's not clear that this is a specifically nuclear issue. Had an area been evacuated due to earthquakes making the ground unstable, due to extreme bushfires destroying every building, would the stress on the elderly be any less?

> It's not clear that this is a specifically nuclear issue An evacuation triggered by a nuclear major accident seems specific to nuclear to me, in the sense: if, instead of this nuclear plant, some field occupied by wind turbines or solar panels were build, there would be no need to evacuate. > Had an area been evacuated due to earthquakes making the ground unstable No human being can control nor counter this sort of…

> We can decide to build wind/solar instead of nuclear reactors.

Or add passive safety measures to nuclear power plants. Fukushima failed because it was still generating too much heat, but that excessive heat couldn’t power a turbine to cool itself down.

Re: Fukushima Reactor: TEPCO robot aims to extract nuclear fuel

#248

Post by Dalewyn » Tue, Oct 08, 2024, 4:09 PM UTC

natmaka wrote: post #169

Dalewyn wrote: post #74

Earlier quoted context omitted.

You literally do not know what transpired. When the tsunami hit and Fukushima #1 lost power and was at risk of meltdown, TEPCO was ready to scuttle the reactors by dumping seawater in them. It would have rendered the reactors unusable, but meltdown would be prevented. The Japanese government at the time, coming from the Prime Minister (Naoto Kan) himself, denied TEPCO from scuttling them because the government wanted…

Naoto Kan was an advocate of nuclear energy, changed his mind after Fukushima, and the industry now tries hard to use him as a scapegoat. Don't worry, experts are perfectly able to maintain a high level of safety (nope), then to assess correctly during an accident (nope: https://www.scientificamerican.com/article/nuclear-power-ody... ), and also to manage the aftermath (nope... https://www.scientificamerican.com/arti…

Congratulations, you're armpits-deep in the Japanese political propaganda machine.

PM Naoto Kan infamously declared "I know nuclear!" in unilaterally ordering TEPCO around during the crisis and ultimately denying their request to scuttle the reactors. Nevermind that TEPCO had the finest nuclear engineers Japan could muster at that moment.

For his valiant achievement of causing a nuclear meltdown and turning back the clock on nuclear power for the better part of a century, PM Naoto Kan was rewarded with merely the loss of his premiership, loss of his parliament seat in the subsequent general election (regained in the same election by proportional vote), and the victim card (sympathy from guys like you).

TEPCO's engineers meanwhile got dragged through the judicial mud before they were finally cleared a few years ago, the train to repair their reputation having left the station long ago.

Re: Fukushima Reactor: TEPCO robot aims to extract nuclear fuel

#249

Post by rbanffy » Tue, Oct 08, 2024, 4:14 PM UTC

troyvit wrote: post #240

lupusreal wrote: post #214

Earlier quoted context omitted.

Rivers are a bad idea because they change course, get dredged, dammed, etc. Into the ocean is best, preferably somewhere deep and remote (simply to reduce the risk of people messing with it.) Deep trenches that would fuck with fish nets anyway are a good place for it.

Sure, but who defines "remote"? We've explored a small percentage of the ocean [1] and most of the places we have explored we've been surprised to find life. In fact NOAA estimates that 91% of species in the ocean have yet to be classified [2]. We'd be dumping what is basically a forever chemical into places that we don't understand. If we can't responsibly keep track of the waste we're producing then we shouldn't pr…

Also, there’s the Godzilla factor you’d need to consider. It’s cheap to dump radioactive material near a deep-ocean vent until something decides to grow and destroys Tokyo. Again.

Now, seriously, screwing with ecosystems we know nothing about is a very bad idea, even if for no other reason than we being unable to study them after we turn them into radioactive deserts.

Re: Fukushima Reactor: TEPCO robot aims to extract nuclear fuel

#250

Post by Dalewyn » Tue, Oct 08, 2024, 4:17 PM UTC

krisoft wrote: post #239

Dalewyn wrote: post #96

Earlier quoted context omitted.

The problem is (or at least was) with the people in political chairs playing power games. No amount of better regulations or technology can prevent fucking morons going on power trips screwing everything up and then get away with it. The nuclear (TEPCO) people in the field were and are amazing, and it is a cardinal sin they got scapegoated for political purposes.

> No amount of better regulations or technology can prevent fucking morons going on power trips screwing everything up and then get away with it. I mean. If the story is true (which I have my doubts about). Then the simple change required would have been to make it clear that TEPCO has the sole authority to decide to scuttle the reactors. The politicians could have been morons going on a power trip all they wanted, a…

>why was the system set up such that it was not already clearly defined

For the simple reason that the 3/11 Tohoku Earthquake defied and rewrote essentially all the geological/maritime scientific and political expectations up to that point.

I doubt the same errors will happen today, but hindsight is 20/20.