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Comment by zython | Hacker News Reader

I was under the impression that thorium-salt reactors have been tried in the past and not deemed "worth" from security and profitability point of view.

What has changed about that ?

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They have different problems that pressured water reactors and are not as applicable to applications that the military would like to use them for. So the government sponsored research labs that were running and experimenting with them stopped doing so when research funds ran out.

Add to the insane risk of investing in anything 'nuclear' and you don't have a lot of available capital. That said, the Chinese who invest in research for other reasons seem to have been working on a number of MSRs which could conceivably advance the state of the art significantly.

Oddly enough, as an American, I am looking forward to the first thing that China builds that "we" American's cannot because we lack expertise and/or technology to do so.

>> Oddly enough, as an American, I am looking forward to the first thing that China builds that "we" American's cannot because we lack expertise and/or technology to do so.

Or too much regulation or politics to allow.

> Or too much regulation or politics to allow.

Or, as a German, too much regulation/politics to Get Shit Done.

Just look what happened to Transrapid (maglev rail). All tech and IP went off to China, and we're stuck in 1980-and-earlier carriages for anything not an ICE or regio trains.

> and we're stuck in 1980-and-earlier carriages for anything not an ICE or regio trains.

Actually, the InterCity and EuroCity fleet was just entirely replaced.

This means the entire fleet – S, Region, InterCity, EuroCity, InterCityExpress – is now replaced, or being replaced, with modern stock.

Offtopic but this means I am totally heading back to ride the new trains :-)

Here the new stock:

InterCity/EuroCity: https://www.bahn.de/p/view/service/zug/fahrzeuge/ic_2.shtml

InterCityExpress 4 (to replace major InterCity routes, and minor InterCityExpress routes): http://www.deutschebahn.com/de/bahnwelt/start_ice4/das_proje...

Exactly right. The one that came in conversation waiting for the eclipse was genetic editing of fetuses to eliminate inherited disease. Setting aside the whole 'designer babies' as a distraction imagine a company that give free genetic treatment for couples seeking to avoid passing on known bad genes. When you walk that forward and look at the cost associated with treating, diagnosing, and supporting people that later get the disease, you begin to see a huge economic 'win' by giving them free genetic help early.

Why would you expect that treatment to be free?

If the cost of editing is not exorbitant (i.e. is lower than the average per-capita cost of paying for the condition being edited away), healthcare providers would be incentivized to pay for the editing to reduce their costs.

The incentives are obviously stronger in single-payer countries, but even in the US you could imagine an insurance company that competed on lower premiums conditional upon certain gene edits being applied to covered children.

> in the US you could imagine an insurance company that competed on lower premiums conditional upon certain gene edits being applied to covered children.

On one hand, this sounds entirely economically reasonable (and even humanitarian).

On the other hand, I fear this would inevitably produce unintended consequences that would shape our society in distopian, sci-fi/horror-flavored ways.

I have no idea how it would actually shake out. Maybe I'm just being anti-intellectual here.

Given the economics, I feel pretty confident predicting that these edits will be mandatory before most people on this site die.

At least you'd probably have to pay a lot more of the bills if you chose not to have genetic problems corrected before birth.

Expect is perhaps too strong a word, the calculus would be the cost burden of providing services and treating the diseases in the uninsured to the cost of providing the genetic services at the start.

The thing is... Abortion is so much cheaper than gene editing, and it gets all the cells at once. More likely is insurance companies try to deny coverage for people with genetic conditions diagnosed before they were born. While this would not fly in todays environment, it is where the economic incentives point.

I thought it was the other way around in fact. That they don't produce nuke-weapon-ready material meant that this avenue was not profitable from a security perspective. I may be recalling this incorrectly and I haven't re-checked but I think that's correct?

No, that is incorrect, though it has often been repeated by less technically informed advocates of the thorium fuel cycle. The vast majority of the world's commercial nuclear reactors are light-water-moderated pressurized water reactors or boiling water reactors (PWR and BWR respectively). The actual military origins of these light water reactors is that they were originally researched for submarine and ship propulsion for the US Navy:

https://en.wikipedia.org/wiki/Light-water_reactor

https://en.wikipedia.org/wiki/Pressurized_water_reactor#Hist...

https://en.wikipedia.org/wiki/Boiling_water_reactor#Evolutio...

The United States and other nuclear weapons states never produced their weapons plutonium from light water reactors. Weapons grade plutonium has typically been produced from uranium in dedicated plutonium-production reactors moderated with heavy water or graphite. (The United States once had a single reactor that also produced commercial electricity along with weapons plutonium, https://en.wikipedia.org/wiki/N-Reactor, but it wasn't a light water reactor either.)

Since uranium fueled light water reactors weren't used to make plutonium for weapons in the first place, the thorium-myth claim that commercial power reactors stuck with uranium so as to make weapons material is ridiculous. The military's early sponsorship of light water reactors for naval propulsion did give uranium-fueled LWRs a significant historical path dependency advantage. I speculate that thorium advocates who continue to repeat the myth about how uranium LWRs became dominant do so because it makes the dominant technology's dominance sound more sinister, hence thorium sound more attractive by contrast.

Oh my god thank you for understanding this and explaining it so well. I spend a lot of time trying to suppress the sinister-LWR myth.

Real reasons MSRs declined include [1]:

* The existing major industrial and utility commitments to the LWR, HTGR, and LMFBR.

* The lack of incentive for industrial investment in supplying fuel cycle services, such as those required for solid fuel reactors.

* The overwhelming manufacturing and operating experience with solid fuel reactors in contrast with the very limited involvement with fluid fueled reactors.

* The less advanced state of MSBR technology and the lack of demonstrated solutions to the major technical problems associated with the MSBR concept.

[1] http://www.energyfromthorium.com/pdf/WASH-1222.pdf

The issue wasn't "light water reactors" it was "uranium fuel cycle". Cheap uranium definitely benefited the US government.

And going back one step Recurecur, isn't a very large part of the the issue "fissionable plutonium" (because bombs) which motivates the "uranium fuel cycle" which means the "thorium fuel cycle" isn't half so interesting.

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