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New design could finally help to bring fusion power closer to reality

phys.org

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Re: New design could finally help to bring fusion power closer to reality

#11

Post by DennisP »

Someone wrote: post #4

"The design could produce a reactor that would provide electricity to about 100,000 people, they say." It would be a huge step forward if this can be built, but there still would be a long way to go. To scale that to "electricity for everyone in the USA", you would need to build about 3,000 of these (or build much bigger ones). And that's for _current_ electricity use, not if everybody starts driving an electric car.…

As long as the cost per kWh is reasonable, smaller unit size is a good thing, since it lowers capital requirements. That's why a lot of people are pushing for small modular fission reactors.

Re: New design could finally help to bring fusion power closer to reality

#12

Post by iaw »

The big problem with controlled fusion, as I understand it, isn't creating a net energy positive fusion reactor like this article implies. The physics is already there, we just need the engineering to catch-up.

The challenge is the materials that compose the reactor become brittle and highly radioactive far faster than usable. Controlled fusion as an energy source isn't just challenging because fusion is difficult, it's also challenging because materials don't handle neutron bombardment well.

I think where this advancement is going to really help is in the iteration phase due to lower build costs but I'm still waiting for a solution to the radioactive economic issues associated with the materials these reactors would be constructed from.

Re: New design could finally help to bring fusion power closer to reality

#14

Post by adeledeweylopez »

iaw wrote: post #12

The big problem with controlled fusion, as I understand it, isn't creating a net energy positive fusion reactor like this article implies. The physics is already there, we just need the engineering to catch-up. The challenge is the materials that compose the reactor become brittle and highly radioactive far faster than usable. Controlled fusion as an energy source isn't just challenging because fusion is difficult, i…

It seems like they address this issue as well:

"Another key advantage is that most of the solid blanket materials used to surround the fusion chamber in such reactors are replaced by a liquid material that can easily be circulated and replaced, eliminating the need for costly replacement procedures as the materials degrade over time. "It's an extremely harsh environment for [solid] materials," Whyte says, so replacing those materials with a liquid could be a major advantage."

Re: New design could finally help to bring fusion power closer to reality

#15

Post by mschuster91 »

DennisP wrote: post #11
Someone wrote: post #4

"The design could produce a reactor that would provide electricity to about 100,000 people, they say." It would be a huge step forward if this can be built, but there still would be a long way to go. To scale that to "electricity for everyone in the USA", you would need to build about 3,000 of these (or build much bigger ones). And that's for _current_ electricity use, not if everybody starts driving an electric car.…

As long as the cost per kWh is reasonable, smaller unit size is a good thing, since it lowers capital requirements. That's why a lot of people are pushing for small modular fission reactors.

> That's why a lot of people are pushing for small modular fission reactors.

Also smaller reactors have less fuel inside and the new MSR designs don't produce plutonium or other weapons-usable byproduct, so they're less attractive targets for terrorists, dirty bomb builders and other threats, not to mention the reduced risk in failure case with the MSR technology.

Re: New design could finally help to bring fusion power closer to reality

#16

Post by moreati »

IANAP, but this sounds at least superficially similar to the reactor that Tokamak Energy are developing. Any nuclear physicists care to weigh in?

""" Tokamak Energy is particularly focused on Spherical Tokamaks, pioneered at Culham, because these compact devices can achieve a much higher plasma pressure for a given magnetic field than conventional tokamaks, i.e. they are more efficient.

Theoretical calculations show that a Spherical Tokamak using high fields produced by HTS magnets could be significantly smaller than other fusion machines currently proposed. For example, a compact ST power plant would have a volume up to 100 times smaller than ITER """ -- http://www.tokamakenergy.co.uk/about-us/

Re: New design could finally help to bring fusion power closer to reality

#17

Post by ZenoArrow »

iaw wrote: post #12

The big problem with controlled fusion, as I understand it, isn't creating a net energy positive fusion reactor like this article implies. The physics is already there, we just need the engineering to catch-up. The challenge is the materials that compose the reactor become brittle and highly radioactive far faster than usable. Controlled fusion as an energy source isn't just challenging because fusion is difficult, i…

> "The challenge is the materials that compose the reactor become brittle and highly radioactive far faster than usable. Controlled fusion as an energy source isn't just challenging because fusion is difficult, it's also challenging because materials don't handle neutron bombardment well."

Isn't that problem solved with aneutronic fusion?

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

Of course we should focus on getting fusion working (working in the sense of providing more energy than we put in), regardless of whether we use the aneutronic approach or not, but as the field develops I'm optimistic we'll find ways to have robust fusion reactors.

Re: New design could finally help to bring fusion power closer to reality

#19

Post by throwaway_yy2Di »

iaw wrote: post #12

The big problem with controlled fusion, as I understand it, isn't creating a net energy positive fusion reactor like this article implies. The physics is already there, we just need the engineering to catch-up. The challenge is the materials that compose the reactor become brittle and highly radioactive far faster than usable. Controlled fusion as an energy source isn't just challenging because fusion is difficult, i…

According to their paper [0], the entire vaccum vessel is considered disposable and might survive only a few months. (It's also explicitly an experimental reactor meant to study neutron radiation damage, so they're hardly claiming it's a practical commercial design. But I think you're right, that the problem is basically unsolved).

    This allows the vacuum vessel to be replaced quickly,
    mitigating first wall survivability concerns, and permits a
    single device to test many vacuum vessel designs and
    divertor materials.
    
    [...] The replaceable vacuum vessel is made of corrosion-
    resistant Inconel 718, which maintains high strength and
    corrosion resistance at elevated temperatures.
    
    [...] Little research has been done regarding how Inconel
    718 responds to the irradiation environment of a fusion
    device [82]. However, studying the response of components to
    fusion neutron effects is part of the motivation for
    ARC. [...] It is unknown if Inconel 718 would behave
    similarly in a fusion neutron spectrum, but one expects the
    vacuum vessel would survive for at least 6-12 months (15-30
    DPA).
[0] http://arxiv.org/abs/1409.3540

Re: New design could finally help to bring fusion power closer to reality

#20

Post by azernik »

iaw wrote: post #12

The big problem with controlled fusion, as I understand it, isn't creating a net energy positive fusion reactor like this article implies. The physics is already there, we just need the engineering to catch-up. The challenge is the materials that compose the reactor become brittle and highly radioactive far faster than usable. Controlled fusion as an energy source isn't just challenging because fusion is difficult, i…

One thing mentioned in the article was another advance in this design, where some of the materials that deal with the most intense neutron bombardment are replaced by a liquid that can be pumped out and circulated. Presumably there's still a containment vessel for this liquid that is a maintenance pain, but they do seem to be working on the problem.
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