Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Six Years After Fukushima, Robots Finally Find Reactors’ Melted Uranium Fuel

mobile.nytimes.com

Post reply on HN
Print view View original

171–180 of 190 posts

Re: Six Years After Fukushima, Robots Finally Find Reactors’ Melted Uranium Fuel

#171

Post by rtpg »

gizmo wrote: post #154
eric-hu wrote: post #151

I long believed that nuclear power was the only energy source cleaner than fossil fuels and scalable enough to meet the energy demands of the world. While that might still be true in some sense, I now believe that humanity isn't ready for nuclear power. Besides the Fukushima and Chernobyl type issues with organizations skimping on design, there's still an outstanding problem of nuclear waste storage. The current nucl…

I agree that renewables are a very good alternative to nuclear power, but in practice moving away from nuclear means doubling down on coal. The problems with nuclear are political, but the alternatives to nuclear power are mired in political conflict as well. As for your dam bursting scenario, something like that actually happened in the 70s when the Banqiao Dam burst. Nearly 200.000 people died. Fukushima had 0 radi…

> in practice moving away from nuclear means doubling down on coal

Is it not possible for us to build out renewable energy on a large scale? My impression was that we're reaching points where it's very cost effective to do so.

Re: Six Years After Fukushima, Robots Finally Find Reactors’ Melted Uranium Fuel

#172

Post by draw_down »

beached_whale wrote: post #62
jjoonathan wrote: post #20

Earlier quoted context omitted.

> Kind of surprising at this point Fukushima was built when the nuclear power industry was 13 years old. Now it's 63 years old. You are seeing the folly of youth, with consequences delayed 60 years, not a design that would be typical of new construction.

Also, from what I understand, they ignored the reports that recommended to put the backup generators on higher ground and to make the sea wall higher. Fukashima is the worst case for that design I think.

It seems bad that nuclear facilities can be built with disregard for good practices.

I feel like a lot of the argument for why this won’t happen again is “oh well you just have to build it right”. But they don’t get built right.

Re: Six Years After Fukushima, Robots Finally Find Reactors’ Melted Uranium Fuel

#173

Post by thesmok »

petepete wrote: post #139
geon wrote: post #138

> https://youtu.be/c5hQ6WlioRE This has to be the worst possible way of sharing information; a video of 2 still images and a computer voice reading a text. Right up there with images inside a word document, inside an email.

YouTube really should be detecting and pushing them to the bottom of search results. Downvoting doesn't appear to have much of an effect.

No it shouldn't. Sometimes videos like this one are a source of unique information.

Re: Six Years After Fukushima, Robots Finally Find Reactors’ Melted Uranium Fuel

#174

Post by gizmo »

RobAley wrote: post #168
gizmo wrote: post #154

Earlier quoted context omitted.

I agree that renewables are a very good alternative to nuclear power, but in practice moving away from nuclear means doubling down on coal. The problems with nuclear are political, but the alternatives to nuclear power are mired in political conflict as well. As for your dam bursting scenario, something like that actually happened in the 70s when the Banqiao Dam burst. Nearly 200.000 people died. Fukushima had 0 radi…

You can't really say 0 deaths, because no one knows. We don't have good epidemiological models for wide-spread low-level dispersal such as was seen at Fukushima, we already know incidences of cancer and gene mutation don't scale linearly with exposure at low levels. There are also associated deaths from psychological factors of those who were evacuated, lost land / business etc. which will only become apparent in yea…

Deaths resulting from psychological factors involving those who were evacuated count when it comes to nuclear energy but not when it comes to dam failures? I don't think this kind of double standard is reasonable.

Besides, I'm pretty sure you just copied the argument about low level exposure from the Fukushima disaster wikipedia page, but you conveniently left out the next sentence: "given the uncertain health effects of low-dose radiation, cancer deaths cannot be ruled out.[11] However, no discernible increase in the rate of cancer deaths is expected."

Scare-mongering about nuclear radiation doesn't help anybody but the coal and gas industry.

Re: Six Years After Fukushima, Robots Finally Find Reactors’ Melted Uranium Fuel

#175

Post by FiatLuxDave »

perlgeek wrote: post #24
civilian wrote: post #18

What is the article talking about when they say "radiation-hardened materials"? What kind of materials might that be?

I don't know what they did in this particular instance, but basically there are two things you can do: shield, or in the case of electronics, use larger parts. The smaller some piece of electronics is, the smaller the charges in there are, and the easier it is to introduce errors with ionizing radiation.

There is a third thing, which is to use a dopant which reduces minority carrier lifetime and provides radiation resistance when manufacturing the semi-conductor. Platinum works really well for this. Unfortunately, this can be a poor engineering tradeoff for some kinds of electronics (power transistors for example) and usually increases electrical resistance. AFAIK nobody manufactures platinum-doped microprocessors.

I used to be a product manager for radiation measurement electronics, and we used platinum-doped diodes for the part intended to go in the beam.

See for example: https://academic.oup.com/rpd/article-abstract/17/1-4/527/311...

http://ieeexplore.ieee.org/document/5436014/

Re: Six Years After Fukushima, Robots Finally Find Reactors’ Melted Uranium Fuel

#176

Post by ataturk »

StreamBright wrote: post #144
dopamean wrote: post #27

Earlier quoted context omitted.

Not but it was in the USSR at the time which many people incorrectly equate with Russia today. To me it's almost ok to say "Russia" when talking about things back then. So long as you don't say Chernobyl is in Russia today.

For you it might be ok but for us who lived in the USSR it is an insult. Just a heads up, you can get into a bar fight anywhere in Eastern Europe referring to these countries as Russia.

Well, it's nice to hear that somebody someplace still hates the USSR enough to get into a bar fight about it! Here in the states we're full up with Marxist fools who are too stupid to understand the ramifications of the system they are actively trying to foist upon the rest of the populace.

Re: Six Years After Fukushima, Robots Finally Find Reactors’ Melted Uranium Fuel

#177

Post by nate_meurer »

frik wrote: post #129
sschueller wrote: post #39

Earlier quoted context omitted.

Wasn't something like that poured under Chernobyl after the accident which prevented the radioactive slurry from entering deep into the ground?

The Russians handled the catastrophe better and faster. International help sender them low tech robots, Russians poured tunnels below within days/weeks with lot of human contractors. But Japan is doing little. Contaminated fluids leak into the sea that swaps to Hawaii and west coast ever since 2011. It's the local culture of loosing face that seems to be at odds with handling it and a major corruption problem. After…

Perhaps it's a language barrier, but this comment makes no sense. The low-tech robots you speak of were uniformly useless, and the people working on the initial cleanup and containment were sent on what were essentially suicide missions. Information is easy to find; just google for stories about the Chernobyl liquidators.

Regarding the radiation, I think you've fallen victim to ignorance of basic facts about the nature of radiation and the oceans. Pretty much anywhere in the Pacific, radiation from Fukushima quickly dropped far below environmental background levels [1].

1 - http://www.whoi.edu/page.do?pid=127297

Here's a good quote from the source above: "The highest levels of cesium (10 Bq/m3) attributable to Fukushima that we have measured were found 1,500 miles north of Hawaii. Swimming every day in the ocean there would still result in a dose 1,000 time smaller than the radiation we receive with a single dental x-ray."

Re: Six Years After Fukushima, Robots Finally Find Reactors’ Melted Uranium Fuel

#178

Post by usertrjx »

geon wrote: post #138

> https://youtu.be/c5hQ6WlioRE This has to be the worst possible way of sharing information; a video of 2 still images and a computer voice reading a text. Right up there with images inside a word document, inside an email.

I think you're lucky a fax was not involved.

Re: Six Years After Fukushima, Robots Finally Find Reactors’ Melted Uranium Fuel

#179

Post by petre »

Cthulhu_ wrote: post #167
petre wrote: post #131

Earlier quoted context omitted.

Expensive. The concrete can also crack in the event of an earthquake.

Not as expensive as having to clean up three reactors worth of nuclear meltdown and a few exploded reactors. I'm sure they can prevent the concrete from cracking in an earthquake.

Cheaper solutions exist, such as the one with borosilicate sand on the bottom of the reactor. Building passive cooling pools with those resources is orders of magnitude more useful because it prevents a meltdown rather than attempting to catch the molten core. The ESBWR uses such a passive cooling design.

https://en.m.wikipedia.org/wiki/Economic_Simplified_Boiling_...

Re: Six Years After Fukushima, Robots Finally Find Reactors’ Melted Uranium Fuel

#180

Post by wahern »

littlestymaar wrote: post #155
eric-hu wrote: post #151

I long believed that nuclear power was the only energy source cleaner than fossil fuels and scalable enough to meet the energy demands of the world. While that might still be true in some sense, I now believe that humanity isn't ready for nuclear power. Besides the Fukushima and Chernobyl type issues with organizations skimping on design, there's still an outstanding problem of nuclear waste storage. The current nucl…

> Maybe all it'd take is a terrorist incident involving nuclear waste. There are so many radiologic sources out there, used for many purposes (medicine, gammagraphy), very dangerous[1] but taken with much less care than nuclear wastes from the nuclear power industry. Stuff like this [2] happen all the time … [1] https://en.wikipedia.org/wiki/Goi%C3%A2nia_accident [2] (in French) https://www.asn.fr/Controler/Actualite…

Or whatever happened in Russia within the past few weeks: https://www.theguardian.com/world/2017/nov/10/nuclear-accide...

I kinda agree with your point: terrorists already have considerable access, theoretically, to radioactive materials. In fact, the materials used for medicine and science are in many ways much more dangerous from a public health perspective given their short, energetic half-lives.

The only substantial, long-term danger from terrorists is to the financial viability of nuclear power. Nobody cares about incidents like the above. But if it were tied to terrorism somehow it would be all over the news and nuclear stocks would plummet. Similarly, for a terrorist incident involving medical use even anti-nuclear activists would have more nuanced reactions, whereas if it involved nuclear power such an incident would herald the end of the world.

Post reply on HN