What if we had commercial fusion power?

[artis]

Well Hydro is very stable and if the dam is maintained correctly also long term. Our biggest Hydro plant is operating non-stop since 1965 with an output of 1000 MWe, so basically it gives the same output as a standard PWR or BWR nuclear reactor.
The problem is that there are only so many rivers around the globe and I think most have already been used? At one point it was a good business model here to build smaller hydro plants , but those small plants really aren't useful to my mind , their total add to the grid is something like maybe 3/5% while their environmental impact outweighs the gain in electricity.
I believe Russia and some other large countries still have some Hydro potential especially on the large rivers in Siberia etc, with HVDC it would even be productive to bring that power closer to population centers, just an idea.I guess the "storage" is a problem when it comes to solar and wind because realistically how do you store thousands of MW for hours? pumped hydro maybe something else? I think batteries at least at current level is a no-go.But when I said we must approach our energy usage wisely I though in every possible way, one example that comes to mind is electric transport, even Elon Musk brought this up in one interview that even if the electricity that powers an electric car is produced in a coal plant it is still better to use that electricity rather than gasoline or diesel because burning fossil fuels in large ovens or machines like gas turbines has a higher thermal efficiency than doing that in small individual engines so still we are getting more energy out for the same amount of CO2 emitted. So speaking about this I wonder why I see so few , almost none electric locomotives in USA? We here in Europe use almost entirely only electric trains both freight and passenger, Also I advocate for electric public transport like trams and trolleys.

I think if we want to be realistic about this we need to do all these minor things because just sitting here waiting for a miracle ain't going to cut it. Fusion I believe is still 50 years into future, given all the testing and commercial application issues etc let's be real 2050 seems more a realistic point by which time if all else is kept as is we will already be in trouble.

 

[Astronuc]

Thirdly the fact that nuclear was first brought into the world as a bomb of unparalleled power and destruction has probably left a huge imprint into the average mind , Hollywood has only helped this myth. Because when you say nuclear- the mouth almost wants to continue with the word - bomb.

Actually, there were nuclear reactors before the bomb. Chicago Pile 1 (CP-1) was the first nuclear reactor. Ref: https://en.wikipedia.org/wiki/Chicago_Pile-1

The plutonium for the Trinity test (first nuclear explosion) and the 'Fat Man' bomb came from the first large scale production reactor, B-reactor, as Hanford.
https://en.wikipedia.org/wiki/B_Reactor

The achievements of the reactors was known only to a few, and not to the public. "Neither university nor city officials were told that an experiment that even its creators judged as risky was taking place in the heart of the second-largest city in the United States." So, as far as the public knew, the first application of nuclear energy was the bombs dropped during World War II.

With respect to electric railroads, there is the Northeast Corridor (NEC) in the US.
https://en.wikipedia.org/wiki/Northeast_Corridor
https://en.wikipedia.org/wiki/Railroad_electrification_in_the_United_States

Capital cost and traffic density are factors in the consideration of electrification.

MetroNorth Commuter Railroad operates on the NEC as well as on intersecting routes in NY and CT. NJ Transit operates similarly in the state of New Jersey (NJ). I believe Chicago has some electrified railways, and many cities, e.g., San Diego, Houston, Seattle, Denver, Los Angeles, Boston, . . . have electrified light rail systems.
https://en.wikipedia.org/wiki/Light_rail_in_North_America#Table_of_United_States_light_rail_systems

The OP is about "What if we had commercial fusion energy", which implies that we have perfected controlled fusion energy generation that is commercially viable. There are issues of tritium supply, if that's the typical system, and somewhat less so if the system uses d+d fusion. For neutronic reactions, there is the matter of transmutation (activation) of structural materials, as well as radiation effects, and how to dispose of the material. Replacing and disposing of activated components will be an economic consideration. Production of special nuclear materials is yet another concern.

 

[artis]

I knew about the "Fermi" Chicago pile and others it's just that my point was about what the public knew and still knows, many still don't know about the existence of these reactors because when more information became available these were already old old news.

Well since you are an expert I would then like to ask you , how exactly in the D-T fuel will tritium be recovered because not only does the reactor has to produce it by neutron bombardment but I also read that tritium is very hard to recover especially from a complicated vacuum vessel so would't it be the case where the actual tritium input for the reactor to continue operation needs to be larger than simply what's needed for x amount of fusion to take place because it also needs to account for the tritium lost to the walls etc? In the popular science literature this is not discussed as much as other factors related to tokamaks and fusion.

 

[Astronuc]

Well since you are an expert I would then like to ask you , how exactly in the D-T fuel will tritium be recovered because not only does the reactor has to produce it by neutron bombardment but I also read that tritium is very hard to recover especially from a complicated vacuum vessel so would't it be the case where the actual tritium input for the reactor to continue operation needs to be larger than simply what's needed for x amount of fusion to take place because it also needs to account for the tritium lost to the walls etc? In the popular science literature this is not discussed as much as other factors related to tokamaks and fusion.

One can find some references searching for "tritium recovery at ITER".

For example, https://nucleus.iaea.org/sites/fusi...website/talks/November 15 Sessions/Willms.pdf

The recovery depends on the form of the Li used to generate T. Recovery of the T leaking out of the plasma and diffusing into the structural material is more complicated, so I don't know how that is addressed at this time. Ostensibly, there would have to be a T recovery system built into the first wall, or between first wall and rest of structure.

 

[artis]

The question is more about whether it will be possible to recover all the deposited and otherwise lost tritium while maintaining a somewhat decent schedule and uptime or maybe there will be a point after a certain amount of operation where a lot of both structural and technical elements will have to be swapped out for new ones while the old ones go to tritium recovery and recycling and some to burial or something like that? But this probably signals a rather lengthy down time while all this is changed.

 

[Astronuc]

The question is more about whether it will be possible to recover all the deposited and otherwise lost tritium while maintaining a somewhat decent schedule and uptime or maybe there will be a point after a certain amount of operation where a lot of both structural and technical elements will have to be swapped out for new ones while the old ones go to tritium recovery and recycling and some to burial or something like that? But this probably signals a rather lengthy down time while all this is changed.

I believe the goal is continual recovery, but that would be system dependent. If the reactor has to be shutdown, and components removed, then that will have to be considered in the operating cycle.

There is this article - Tritium recovery from an ITER ceramic test blanket module — process options and critical R&D issues
https://www.sciencedirect.com/science/article/pii/S0920379600001836

However the article must be purchased if one is not a subscriber.

 

[mfb]

You can breed on average more than one tritium nucleus per fusion reaction, sacrificing a bit of the power produced: ${}^7Li + n \to {}^4He + T + n$ (-2.47 MeV). Some tritium loss is okay. A power plant will find some sweet spot between breeding and power. Initially power plants might want to breed more to fuel new power plants.

 

[etudiant]

One issue for the experts.
The time to build for large reactors of any type, whether fusion or fission, in the US as well as in Europe has become so long as to prevent them from getting built there at all, although China and India still seem to manage more reasonable schedules for large new fission plants.
Small reactors might be a more acceptable approach for the 'Western World', more easily managed in an emergency and more readily built on an industrial scale.
There are several small fission reactor designs under study to serve this potential opportunity, but I've not seen any small scale fusion designs, even conceptually.
Is small scale fusion inherently impossible or is it simply much more difficult?

 

[mfb]

We don't know how to build it smaller. A smaller plasma has a larger surface area compared to its volume - it loses its energy faster, it gets more difficult to bring it to a stage where fusion releases enough energy to keep it hot. There might be ways to achieve this with smaller reactors but we don't know how.

Fission has a minimal size of the core as well but this minimal size is much smaller.

 

[etudiant]

We don't know how to build it smaller. A smaller plasma has a larger surface area compared to its volume - it loses its energy faster, it gets more difficult to bring it to a stage where fusion releases enough energy to keep it hot. There might be ways to achieve this with smaller reactors but we don't know how.

Fission has a minimal size of the core as well but this minimal size is much smaller.

Guess the square cube law is not a friend of small fusion designs.
Would a stellarator such as the German Wendelstein 7 be less impacted?

 

[phyzguy]

Guess the square cube law is not a friend of small fusion designs.
Would a stellarator such as the German Wendelstein 7 be less impacted?

I don't see why. It still loses energy out the surface and generates energy in the volume. There is no way around this.

 

[consuli]

Someone told me, that

1. nuclear fusion is overvalued anyway, as it were neutron rich, thus also producing radioactive contamination of the fusion reactor.
2. the really missing thing for a clean nuclear power technology would be some kind of "nuclear radiation to electrical energy converter" (similar to a solar cell).

Is that true?

 

[etudiant]

Fusion reactions that largely produce charged particles do exist, but require much more aggressive temperatures, so they have not been pursued as a priority.
Afaik, there are some ventures that hope to achieve this. They propose inducing fusion via ion beams rather than magnetically confined plasmas.
Whether this can be made to work is unknown. The leading entity pursuing this path is Tri Alpha Energy, web site:
https://tae.com/company/ .

 

[Astronuc]

These guys are most probably working under militarily classified conditions.

No. Companies/corporation like LMCO have proprietary interests that they protect. Westinghouse, GE/GNF and Framatome each have their own proprietary interests, or intellectual property, that they do not share except with the regulators and their customers, usually with some protection such as a non-disclosure agreement.

• nuclear fusion is overvalued anyway, as it were neutron rich, thus also producing radioactive contamination of the fusion reactor.

• the really missing thing for a clean nuclear power technology would be some kind of "nuclear radiation to electrical energy converter" (similar to a solar cell).

At the moment, even the easiest fusion reaction, d+t, is challenging to develop into a viable fusion power system. Some have contemplated d+d, which produces lower energy neutrons part of the time, and p+t part of the time, but one still has to address neutrons. Aneutronic reactions like d+³He, would be ideal; however, the fact that He has Z=2 means higher temperatures for fusion and slightly higher losses (bremsstrahlung and cyclotron) due to more electrons per nuclei. Energy losses increase with Z, since more free electrons are present to maintain charge neutrality. More electrons at a given temperature mean greater pressure. Even so, in a d+³He plasma, one has to deal with d+d reactions, which are more like than d+³He at the same temperature, while ³He+³He would be much less.

There have been and are concepts for so-called direct conversion, in which electrons are captured/collected separately, passed to the load then recombined with positively charged nuclei. That is also a challenge.

 

[gmax137]

Someone told me, that

1. nuclear fusion is overvalued anyway, as it were neutron rich, thus also producing radioactive contamination of the fusion reactor

Activation of the materials in the fusion machine is probably a much smaller problem than the radiation release from a coal burning station (in the stack discharge and in the fly ash). And nobody cares about that.

 

[artis]

because literally nobody knows about that...

 

[russ_watters]

Activation of the materials in the fusion machine is probably a much smaller problem than the radiation release from a coal burning station (in the stack discharge and in the fly ash). And nobody cares about that.

because literally nobody knows about that...

I'm not sure it is that simple. I see a couple of other possible angles:

It is my understanding that at one time people really did believe that "the solution to pollution is dilution". Under that model, pollution of any kind injected into the atmosphere is easier to deal with than a pile of it that you have to find a home for. Obviously, that's the opposite of the current paradigm.

Arguments against coal have gotten stronger lately, so they may not need extra help from public recognition of this issue to shut it down. The problem though is that coal is the hidden other principal in the proxy fight between nuclear and intermittent renewables. E.G., environmentalists think they are arguing against nuclear (fission today, maybe fusion later) and in favor of intermittent renewables when in fact they are often arguing against nuclear and by default in favor of coal.

This was discussed some in @phyzguy's thread on attitudes toward fusion...

 

[gmax137]

because literally nobody knows about that...

just who are you calling "nobody"? Me? OK . How about these guys

https://www.scientificamerican.com/article/coal-ash-is-more-radioactive-than-nuclear-waste/

 

[artis]

My reply was meant as a figure of speech, the majority of the population simply thinks coal is bad because of CO2 and nothing else as well as they think nuclear is dangerous because of "radioactivity". People tend to memorize things by remembering simple phrases attached to complicated issues.

Ask any ordinary person who is not a scientist about coal and radioactivity and I am sure they will not know what you are talking about.Although I must say i find the link to the article from Scientific American that you posted "fake news" because it's title says "
Coal Ash Is More Radioactive Than Nuclear Waste" although anyone with a basic understanding of nuclear physics knows this is not true as nuclear waste aka the waste from a nuclear reactor core aka burnt up fuel has orders of magnitude higher radioactivity and much more different decaying isotopes than a pile of coal ash, which by the way should have no decaying isotopes because coal never undergoes fission unlike uranium in a fuel pellet. Only later in the article it says "In fact, the fly ash emitted by a power plant—a by-product from burning coal for electricity—carries into the surrounding environment 100 times more radiation than a nuclear power plant producing the same amount of energy."

So now we are not talking about radioactive waste aka used nuclear fuel but instead we are talking about the amount of radioactive substance release from a plant during operation which is a totally different category. Also a well maintained nuclear plant is not supposed to have any waste release into the environment and coal plant smoke and ash release doesn't release radioactive waste instead it releases the leftover powder or particles which contain small amounts of natural uranium which has the same emission levels as many rocks also containing natural uranium etc.

And basically the article itself denies its seriousness further down as experts from ORNL and other places say that even though coal has traces of natural uranium and thorium the levels are not normally dangerous etc etc, so we are now back to the primary danger of burning coal which is CO2 emission and secondary which is large piles of ash and trash. I kind of feel the article is not up to the standards of being a serious scientific article.

 

[Klystron]

Oddly enough in an environment associated with past nuclear weapon tests, with major sunlight and few coal resources; air pollution from coal-fired power plants on federal lands remains a health hazard. Several reports mention ozone and fine particulate damage to the lungs of tribal members living nearby. While the situation is improving with solar power stations online, this example from summer 2018 indicates wide spread pollution.

https://www.lasvegasnow.com/news/epa-hears-from-paiute-tribe-over-air-quality/75430322

 

[russ_watters]

Mod Note: Several posts were re-located from the "State of Nuclear Fusion Power" thread.