# What if we had commercial fusion power?

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#### russ_watters

Mentor
A large number of posts have been deleted, a member will not be returning to the thread, and it is re-opened.

The mods recognize this is a public policy discussion and a speculative one at that; speculating about opinions of people who are not participating in the thread and may believe things that are factually wrong or unreasonable. For that reason it is critical to distinguish between your own beliefs/claims/statements of fact and those you are attributing to speculated opponents of fusion 30 years from now.

We'll give this one more try...

#### russ_watters

Mentor
Someone here said earlier that we are better off with the devils that we know than the ones we don't. I think it explains why many people fear anything nuclear- they simply don't know much about, it's just bedtime horror stories for them and so just like death , the unknown frightens us.
This irrationality also applies to planes, as another example. Commercial air travel has gotten so safe we in the US recently had our first fatality in nine years (1, due to an uncontained engine failure). Except for non-fatal accidents in the US and fatal ones abroad, it was out of the news. But an awful lot of people are still afraid to fly, and those numbers aren't changing much.

Tellingly, 16% of Americans actually believe it is safer to drive than fly. Or after flipping and subtracting out the unsure, only 47% - half - believe it is safer to fly than drive. Wow.

This is the sort of irrationality the nuclear industry is up against. In my first post, I speculated that this is not going to be an issue for fusion, but clearly that's just a prediction/guess. Who knows that minor word twist the public might seize on to generate an irrational fear.

https://flyfright.com/statistics/
https://today.yougov.com/topics/lifestyle/articles-reports/2014/03/19/fear-flying

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#### mfb

Mentor
A fusion reactor would need to store a lot of tritium but only a small fraction would be volatile. The rest is in the blanket or can be stored in a solid chemical compound. Decay heat is easy to handle passively. In addition I don’t see which event would be a threat to it.

I expect some opponents of fission to oppose fusion for the same irrational reasons, with the same rhetoric. Power plant operators might call it fusion power but the opponents will probably use the existing words - refer to atoms, radioactivity and so on. As long as a significant fraction of the population would vote to “ban all atoms” it is easy to scare people of fusion.

Gold Member

#### russ_watters

Mentor
I expect some opponents of fission to oppose fusion for the same irrational reasons, with the same rhetoric. Power plant operators might call it fusion power but the opponents will probably use the existing words - refer to atoms, radioactivity and so on.
It's so tough to know for sure, but it's as good a bet as any that the existing trigger words could still be applied. Another for the list: radiation (nevermind the electric heater under your desk).

#### mfb

Mentor
The Germans have “Atomstrom”, literally “atomic electricity” - quite ironic for an energy source that comes from the nucleus and doesn’t rely on atomic transitions (unlike coal, oil, solar power, ...)

#### artis

Russ mentioned an old but valid point about flying being safer in numbers than driving a car, I think the problem here is partly psychological and not so much statistical or lack of information. A plane is controlled by a pilot and in these days by computers etc so the passenger has no control over what is happening meanwhile in a car you have almost full control over every minor detail , even though due to human factor cars on a highway filled with them are less safe than a plane for people driving a car feels (I believe) emotionally safer.

The same goes for nuclear. Coal is basically nothing but a big oven and a large chimney this is something we can all relate to even those who have very little science understanding because we all have had something to do with ovens, especially our ancestors for whom it was the primary way of surviving.
Nuclear on the other hand is something relatively new, after all there are still people around who were young when we made our first bombs and reactors.
Secondly nuclear just like electronics is sort of the "genie in the bottle" , Nobody except those who read much about or work with it know much about it so there is this unknown factor plus the feeling that you cannot control it.
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.

I think these factors combined with the addition of some stupid mishaps and blatant disregard (Chernobyl, Mayak plant, maybe even TMI and to some extent Fukushima) have made people fear the word nuclear.
What I want to say is the word fission is very close to the word fusion , just two letter difference , so good luck with explaining that to the average Joe and telling him his potatoes will not become mutant ninja turtles.

I think only time and education plus (sadly) running out of other options will make society change its mind.

#### mfb

Mentor
We have other options. So far they are much more expensive than fission. By the time fusion is an option (around the end of the lifetime of fission reactors built now, hopefully) they might be cheaper than both.

#### artis

What "other options" exactly were you referring to?

I personally think that we should approach wisely everything we have, I think the smart thing to do would be to keep pushing renewable energy like wind and solar to it's maximum (without overkilling it) while at the same time closing coal plants and swapping them (the so called base load) with more nuclear and if not possible then natural gas. It's not that we need to close all coal plants at the same moment it's just that we need to reduce enough emissions in order to keep climate change steady while we are still working on better solutions.

I live in a smaller country and we supply almost entirely ourselves with 3 medium size hydro plants so our energy is already emissions free, sadly not everyone has that option, some African countries due to their sunny weather and remotely populated areas could maybe almost fully support themselves from wind and solar alone with some small base load for backup.

#### mfb

Mentor
What "other options" exactly were you referring to?
A lot of solar+wind with a lot of storage, or excessive solar+wind and large grids with less storage. Hydro, geothermal energy and a bit of biomass where available/useful. Currently too expensive in most places but that might change.

#### 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

Staff Emeritus
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

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.

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#### 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

Staff Emeritus
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/fusionportal/Technical Meeting Proceedings/4th DEMO/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 alot 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

Staff Emeritus
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 alot 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

Mentor
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

Gold Member
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

Mentor
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

Gold Member
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?

"What if we had commercial fusion power?"

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