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Comment by Semirhage | Hacker News Reader

Fusion requires lots of time, or a few miracles.

Renewable storage and transmission requires some breakthroughs. Maybe we could do it Soon, maybe in decades.

Fission requires political will, no miracles, no breakthroughs. We could have been doing it last year.

I think this is incorrect. Renewables + Storage is possible now. It's only a matter of price. At marginal cost right now solar+wind are cheaper than alternatives, at total system costs it's within a factor of two (or at break even for optimistic studies) of the current system and falling.

Fusion is not possible now. As climate change is happening now, any delay in transitioning to clean and available solutions is purely ideology driven.

Also, Fission is a potential dangerous technology. Not only for accidents, also for intentional missuse.

The wider it is avaiable, the easier it is for certain groups to get more dangerous.

This too is a political will problem. Designs for proliferation-resistant gen IV nuclear plants have existed for a long time, and many have been tested. We don't use them because nobody builds nuclear plants any more out of overblown fears of meltdowns (which, incidentally, also can't occur in most gen IV designs).

Hm, this is the first time I heard that you can build a fissoon reactor which cant melt down. Or can't be made into weapons.

But I don't know much about the topic. Short google search shows that your claims are not proven and at least controversal:

https://theecologist.org/2017/oct/03/james-hansens-generatio...

The "can't melt down" property is usually referred to as "passive safety": https://en.wikipedia.org/wiki/Passive_nuclear_safety . These tend to have components that cause all of the nuclear fuel to passively flow out of the reactor and into a cooling chamber in the event of coolant failure. In liquid-fueled designs, this is accomplished via a "freeze plug," essentially a cork made of a low-melting-point material at the bottom of the reaction chamber that's kept solid by active cooling and rapidly melts in the event of a power failure such that the reaction chamber drains. Equivalent mechanisms exist for pebble bed reactors, though, where all the pebbles fall into a cooling chamber. In either case, production reactors have been build that include these features and the physics are very well understood.

Proliferation resistance is trickier, and not all gen IV designs focus here. There are a couple of areas of attention here. The first, and probably more mature development-wise, are alternative fuel cycles like the Thorium fuel cycle that don't produce easily usable fissile material out the other end (and do produce a bunch of U232, which in addition to being non-fissile is also difficult to steal because it's super-dangerous to handle). Secondly, there are designs that breed and then immediately burn fuel in situ without reprocessing, such that there's no point during which the fissile material exists outside the reactor to be stolen. I don't think any of this class have actually been built yet, but the Traveling Wave design is probably furthest along, and TerraPower is building one of those in China with a target completion date of ~2025.

Two important caveats though: these are "proilferation-resistant" in the sense that fuel would be hard for non-state actors to steal; state actors are another concern as that article points out, but they also don't really need to breed fuel, and can just enrich uranium directly without that much difficulty, as Iran and North Korea have both demonstrated, if they're willing to pay for it. At this point the physics are very well-understood, so this is a problem in need of diplomatic solutions more than technological ones. And second, the focus here is on material for fission weapons. I don't think any nuclear technology has good defenses against using material for dirty bombs.

All of that said, I'd still stand by my original point that newer designs are well-understood and dramatically better in these respects than most currently operating plants, and are only not being built (at least in the US and Europe) for political reasons.

"All of that said, I'd still stand by my original point that newer designs are well-understood and dramatically better in these respects than most currently operating plants, and are only not being built (at least in the US and Europe) for political reasons."

Well your original point was written a bit more absolute...

With this I go along. And as I said, I also prefer fission as the short term solution. But only as a transition on the way to fully renewable (or allmost full, I am for pragmatism). As there are just many problem involved with nuclear power, like danger and waste and the need for uranium, etc. that you would not have with solar energy. So this is the goal for me, fission power only as a way to get there or where there are not really other options. (submarines, spacemissions, etc.)

I am extremely skeptical about such claims. One such alternative design was the THTR design, which was implemented in the Jülich AVR reactor. It was also claimed to be passively safe.

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

But there were incidents when the plant was basically out of control. Worse, the design is based on graphite spheres which contain the fuel. That is only safe as long as the spheres in the hot reactor do not come into contact with air, which will cause them to burn, or with water, which will form hydrogenium-oxygen mixtures. Burning graphite was both a main ingredient in the Windscale fire, and in the Chernobyl disaster. There were also important mechanical problems with the spheres. In retrospect, these claims for passive security were unwarranted and the plant was dangerous. With the experience from the AVR, one can also say, that the nuclear industry is not transparent at all about safety problems. Also, it is not only very hard to make such plants inherently safe, if this also very expensive. Unfortunately, this conflicts with the goal of every company, which is to make a profit which is as large as possible.

The AVR was also not a Gen IV reactor (about which the parent/gp claims were made), and was built over 40 years ago. In fact construction began in 1961, and it was commissioned in ‘69, so really it was tech from 57 years ago that was put into practice 49 years ago.

Or fear of bankruptcy.

Or actual bankruptcy:

https://en.wikipedia.org/wiki/Westinghouse_Electric_Company#...

> Fission requires political will, no miracles, no breakthroughs. We could have been doing it last year.

Assuming you are in the US, you forgot how close the Three Miles Island accident was to cause an US version of Chernobyl in the East coast.

I’m not in the US, but I do remember. The thing is I remember other disasters relating to energy, including yearly deaths from pollution. It’s not as though gas, oil, and coal production or use are somehow safe, free from catastrophic failure, and subsequent deaths.

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