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THE Nuclear Fusion Thread Pt. 3

Discussions of conventional and alternative energy production technologies.

Re: THE Nuclear Fusion Thread Pt. 3

Unread postby kublikhan » Wed 10 Apr 2019, 18:48:43

EnergyUnlimited wrote:@Tanada,
OK, lats say that they (whoever are "they") got this fusion reactor working.
Now tell me, how they are going to handle these pesky 14 MeV neutrons?

There will be an immense corrosion of reactor walls... very frequent maintenance and associated costs etc.
This problem is going to be explored in the IFMIF project. IFMIF-DONES is currently in the engineering design phase.

The International Fusion Materials Irradiation Facility, also known as IFMIF, is a projected material testing facility in which candidate materials for the use in an energy producing fusion reactor can be fully qualified. IFMIF will be an accelerator-driven neutron source producing a high intensity fast neutron flux with a spectrum similar to that expected at the first wall of a fusion reactor using a deuterium-lithium nuclear reaction.

Background
The deuterium-tritium fusion reaction generates mono-energetic neutrons with an energy of 14.1 MeV. None of the commonly available neutron sources are adequate for fusion materials testing for various reasons. The construction of IFMIF is recommended in the European Roadmap for Research Infrastructures Report.
International Fusion Materials Irradiation Facility

The early construction of an 'Early DEMO' requires the accelerated construction of a neutron irradiation plant. This initial irradiation plant will have reduced specifications in terms of accumulated damage of the irradiated materials (30-40 dpa instead of 150 dpa). Thus, in the European framework it was decided to design and build a facility capable of producing the specified amount of damage as soon as possible. A discussion period was opened to determine the specifications of this so-called Early Neutron Source (ENS).

Following a proposal by the LNF, the design adopted for ENS is DONES (DEMO-Oriented Neutron Source), which basically consists of a simplification of IFMIF. Currently, the ENS is one of the EUROfusion Work Packages.

DONES will thus be similar to IFMIF but will only have one accelerator, and it will only include the irradiation modules required to test the structural materials, without a laboratory for the characterization of the irradiated samples. Based on these simplifications, both the cost and the time required for the design and construction of the facility will be significantly reduced. Also, DONES is being designed in such a way that it could eventually be upgraded in order to meet the full capabilities of IFMIF. The objective of the ENS project in the framework of EUROfusion (2015-2018) is the development of the R&D and the engineering activities required to start the construction of the facility before 2020.
IFMIF-DONES

In this paper, an overview and the present status of the IFMIF-DONES engineering design is presented for a generic site, making emphasis on the recent design evolution from previous phases.
The IFMIF-DONES project: preliminary engineering design

steps for implementation
EUROfusion and Fusion for Energy (F4E) started in 2015 a process to develop the engineering design of DONES and to identify possible EU sites to host the facility. In December 2017, F4E positively evaluated the joint Spain-Croatia proposal to site DONES in Granada. As the IFMIF-DONES enters the Roadmap 2018, it will be eligible for the Preparatory Phase grant by the EC and, simultaneously, will begin the Implementation Phase with the initial steps for the construction of the civil engineering infrastructure.
IFMIF-DONES
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Re: THE Nuclear Fusion Thread Pt. 3

Unread postby Tanada » Thu 11 Apr 2019, 03:20:25

EnergyUnlimited wrote:@Tanada,
OK, lets say that they (whoever are "they") got this fusion reactor working.
Now tell me, how they are going to handle these pesky 14 MeV neutrons?

There will be an immense corrosion of reactor walls... very frequent maintenance and associated costs etc.


Personally I would line the walls with cadmium steel tanks and fill the tanks with asphalt, but it is not my project. Cadmium is a good neutron absorbent and asphalt has serious advantages over water as a neutron moderator. Its a solid at room temperature and doesn't boil until it gets above 500 C degrees so it acts as something of a heat sink if an emergency takes place.

Failing that you can always go with the old standby, heavy water using deuterium isotope of hydrogen like Canada uses in their fission reactor designs. You can also add a lot of boron to the water as was originally done in the emergency shutdown systems for fission reactors.
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Re: THE Nuclear Fusion Thread Pt. 3

Unread postby EnergyUnlimited » Thu 11 Apr 2019, 16:00:15

Tanada wrote:
EnergyUnlimited wrote:@Tanada,
OK, lets say that they (whoever are "they") got this fusion reactor working.
Now tell me, how they are going to handle these pesky 14 MeV neutrons?

There will be an immense corrosion of reactor walls... very frequent maintenance and associated costs etc.


Personally I would line the walls with cadmium steel tanks and fill the tanks with asphalt, but it is not my project. Cadmium is a good neutron absorbent and asphalt has serious advantages over water as a neutron moderator. Its a solid at room temperature and doesn't boil until it gets above 500 C degrees so it acts as something of a heat sink if an emergency takes place.

Failing that you can always go with the old standby, heavy water using deuterium isotope of hydrogen like Canada uses in their fission reactor designs. You can also add a lot of boron to the water as was originally done in the emergency shutdown systems for fission reactors.

These neutrons are needed to breed back trithium (from Li-6 lets say). You cannot afford to waste them. Another thing is that you need to make inner walls of reactor out of something. Any known solid materials are going to be eroded in no time at all. I don't think that cadmium steel would be an exception.
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Re: THE Nuclear Fusion Thread Pt. 3

Unread postby Antaris » Sat 15 Feb 2020, 00:05:27

Lion
Maybe maybe not.
Got to give it a try as we are running out of other options.
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Re: THE Nuclear Fusion Thread Pt. 3

Unread postby dissident » Sat 15 Feb 2020, 11:52:47

For some reason the most obvious issue with toroidal magnetic confinement fusion reactors is not mentioned in the coverage of these devices. All of the reactors since the small desktop variants decades ago do not have enough plasma isolation from the wall to function. This problem is a scaling problem. Small devices (like all of the current and previous designs) have way too much deviation of plasma from the ideal magnetic torus sheets. This noise enables parasitic current into the walls of the reactor and contamination of plasma with vaporized wall material. Hence, suppression of fusion.

There was a paper on this issue that seems to have been forgotten outside the expert community. ITER is supposedly big enough to overcome the noise issue, but I have not seen any proof of this. So I suspect that it will be a flop. We may need another factor of 10 scaling (i.e. 1000 times larger reactor) to overcome the noise issue. In the large scale limit, the plasma confinement to magnetic iso-surfaces becomes more ideal due purely to geometry (note that the noise does not scale with size since it depends on the specific energy of the plasma, this enables the cross-surface mobility of charged particles composing the plasma to be scaled away). So there is a progressive isolation of the plasma from the reactor walls.
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Re: THE Nuclear Fusion Thread Pt. 3

Unread postby EnergyUnlimited » Sat 15 Feb 2020, 17:28:01

@dissident,
Those pesky 14MeV neutrons are making commercial D+T fusion non-starter.
No existing material will stand them for more than few weeks in commercial power generation reactor setup and replacing reactor walls every few weeks makes it all impractical.

Other fusion setups like He-3 + D are far more challenging on the other hand.

So we need to satisfy our energy needs with gravitational confinement fusion reactor which is about 8 light minutes away.

On odd occasion we may supplement it with flash fusion setups useful for example for evaporating a city (though they really tend to be about as much fission as fusion when designed in an optimal way).
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Re: THE Nuclear Fusion Thread Pt. 3

Unread postby dissident » Sat 15 Feb 2020, 20:01:06

EnergyUnlimited wrote:@dissident,
Those pesky 14MeV neutrons are making commercial D+T fusion non-starter.
No existing material will stand them for more than few weeks in commercial power generation reactor setup and replacing reactor walls every few weeks makes it all impractical.

Other fusion setups like He-3 + D are far more challenging on the other hand.

So we need to satisfy our energy needs with gravitational confinement fusion reactor which is about 8 light minutes away.

On odd occasion we may supplement it with flash fusion setups useful for example for evaporating a city (though they really tend to be about as much fission as fusion when designed in an optimal way).



The 14 MeV neutrons are not why there is no sustained fusion. The plasma loses vast amounts of energy by "short circuiting" to the tokomak wall and at the same time is quenched by heavy, non-fusable elements from that same wall.

BTW, current understanding of solar physics is not as complete as touted. There is evidence that the Coronal Mass Ejection events are energized by fusion occurring in magnetic flux tubes being stretched and deformed by magneto-hydrodynamics of the Sun and fusion is not confined to the solar core.
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Re: THE Nuclear Fusion Thread Pt. 3

Unread postby EnergyUnlimited » Sun 16 Feb 2020, 03:03:53

dissident wrote:The 14 MeV neutrons are not why there is no sustained fusion. The plasma loses vast amounts of energy by "short circuiting" to the tokomak wall and at the same time is quenched by heavy, non-fusable elements from that same wall.

The issue with 14 MeV neutrons is not about sustained fusion.
It is about unsustainable expenses of reactor maintenance once sustained fusion is achieved.

BTW, current understanding of solar physics is not as complete as touted. There is evidence that the Coronal Mass Ejection events are energized by fusion occurring in magnetic flux tubes being stretched and deformed by magneto-hydrodynamics of the Sun and fusion is not confined to the solar core.

That is interesting but I am not surprised that we have rather patchy understanding of solar physics.
We just cannot recreate Sun in lab and the smallest possible model of Sun is Sun itself.
But we cannot observe details of interior with adequate accuracy. The inly information from the core available to us in untampered form comes in form of neutrinos.
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Re: THE Nuclear Fusion Thread Pt. 3

Unread postby Tanada » Sun 23 Feb 2020, 15:50:25

Radical hydrogen-boron reactor leapfrogs current nuclear fusion tech

"We are sidestepping all of the scientific challenges that have held fusion energy back for more than half a century," says the director of an Australian company that claims its hydrogen-boron fusion technology is already working a billion times better than expected.

HB11 Energy is a spin-out company that originated at the University of New South Wales, and it announced today a swag of patents through Japan, China and the USA protecting its unique approach to fusion energy generation.

Fusion, of course, is the long-awaited clean, safe theoretical solution to humanity's energy needs. It's how the Sun itself makes the vast amounts of energy that have powered life on our planet up until now. Where nuclear fission – the splitting of atoms to release energy – has proven incredibly powerful but insanely destructive when things go wrong, fusion promises reliable, safe, low cost, green energy generation with no chance of radioactive meltdown.

It's just always been 20 years away from being 20 years away. A number of multi-billion dollar projects are pushing slowly forward, from the Max Planck Institute's insanely complex Wendelstein 7-X stellerator to the 35-nation ITER Tokamak project, and most rely on a deuterium-tritium thermonuclear fusion approach that requires the creation of ludicrously hot temperatures, much hotter than the surface of the Sun, at up to 15 million degrees Celsius (27 million degrees Fahrenheit). This is where HB11's tech takes a sharp left turn.

The results of decades of research by Emeritus Professor Heinrich Hora, HB11's approach to fusion does away with rare, radioactive and difficult fuels like tritium altogether – as well as those incredibly high temperatures. Instead, it uses plentiful hydrogen and boron B-11, employing the precise application of some very special lasers to start the fusion reaction.

Here's how HB11 describes its "deceptively simple" approach: the design is "a largely empty metal sphere, where a modestly sized HB11 fuel pellet is held in the center, with apertures on different sides for the two lasers. One laser establishes the magnetic containment field for the plasma and the second laser triggers the ‘avalanche’ fusion chain reaction. The alpha particles generated by the reaction would create an electrical flow that can be channeled almost directly into an existing power grid with no need for a heat exchanger or steam turbine generator."

HB11's Managing Director Dr. Warren McKenzie clarifies over the phone: "A lot of fusion experiments are using the lasers to heat things up to crazy temperatures – we're not. We're using the laser to massively accelerate the hydrogen through the boron sample using non-linear forced. You could say we're using the hydrogen as a dart, and hoping to hit a boron , and if we hit one, we can start a fusion reaction. That's the essence of it. If you've got a scientific appreciation of temperature, it's essentially the speed of atoms moving around. Creating fusion using temperature is essentially randomly moving atoms around, and hoping they'll hit one another, our approach is much more precise."

"The hydrogen/boron fusion creates a couple of helium atoms," he continues. "They're naked heliums, they don't have electrons, so they have a positive charge. We just have to collect that charge. Essentially, the lack of electrons is a product of the reaction and it directly creates the current."

A small pellet of hydrogen/boron fuel is placed in a large sphere and hit with two lasers simultaneously to create a fusion reaction that directly generates electricity with no steam turbines required

HB11

The lasers themselves rely upon cutting-edge "Chirped Pulse Amplification" technology, the development of which won its inventors the 2018 Nobel prize in Physics. Much smaller and simpler than any of the high-temperature fusion generators, HB11 says its generators would be compact, clean and safe enough to build in urban environments. There's no nuclear waste involved, no superheated steam, and no chance of a meltdown.

"This is brand new," Professor Hora tells us. "10-petawatt power laser pulses. It's been shown that you can create fusion conditions without hundreds of millions of degrees. This is completely new knowledge. I've been working on how to accomplish this for more than 40 years. It's a unique result. Now we have to convince the fusion people – it works better than the present day hundred million degree thermal equilibrium generators. We have something new at hand to make a drastic change in the whole situation. A substitute for carbon as our energy source. A radical new situation and a new hope for energy and the climate."

Indeed, says Hora, experiments and simulations on the laser-triggered chain reaction are returning reaction rates a billion times higher than predicted. This cascading avalanche of reactions is an essential step toward the ultimate goal: reaping far more energy from the reaction than you put in. The extraordinary early results lead HB11 to believe the company "stands a high chance of reaching the goal of net energy gain well ahead of other groups."

“As we aren’t trying to heat fuels to impossibly high temperatures, we are sidestepping all of the scientific challenges that have held fusion energy back for more than half a century,” says Dr McKenzie. “This means our development roadmap will be much faster and cheaper than any other fusion approach. You know what's amazing? Heinrich is in his eighties. He called this in the 1970s, he said this would be possible. It's only possible now because these brand new lasers are capable of doing it. That, in my mind, is awesome."

Dr McKenzie won't however, be drawn on how long it'll be before the hydrogen-boron reactor is a commercial reality. "The timeline question is a tricky one," he says. "I don't want to be a laughing stock by promising we can deliver something in 10 years, and then not getting there. First step is setting up camp as a company and getting started. First milestone is demonstrating the reactions, which should be easy. Second milestone is getting enough reactions to demonstrate an energy gain by counting the amount of helium that comes out of a fuel pellet when we have those two lasers working together. That'll give us all the science we need to engineer a reactor. So the third milestone is bringing that all together and demonstrating a reactor concept that works."

This is big-time stuff. Should cheap, clean, safe fusion energy really be achieved, it would be an extraordinary leap forward for humanity and a huge part of the answer for our future energy needs. And should it be achieved without insanely hot temperatures being involved, people would be even more comfortable having it close to their homes. We'll be keeping an eye on these guys.


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Re: THE Nuclear Fusion Thread Pt. 3

Unread postby dissident » Sun 23 Feb 2020, 16:04:05

This is not sustained and is not fusion. This is

H + B -> 2 He

The He produced is not cycling back into the reaction and Boron is fissioned in the process. In other words, this is a fancy conventional reactor that is burning some fuel stock in a fancy way. It is not even a standard nuclear reactor that uses a neutron cascade that amplifies the fission energy release. This concept just fissions Boron in one step.

Boron has atomic number 5 and Helium has atomic number 2. Any isotope variations would always have the Boron having a nucleus with more nucleons than the Helium. So clearly this is a fission reaction and not a fusion reaction.
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Re: THE Nuclear Fusion Thread Pt. 3

Unread postby EnergyUnlimited » Sun 23 Feb 2020, 16:21:22

dissident wrote:This is not sustained and is not fusion. This is

H + B -> 2 He

The He produced is not cycling back into the reaction and Boron is fissioned in the process. In other words, this is a fancy conventional reactor that is burning some fuel stock in a fancy way. It is not even a standard nuclear reactor that uses a neutron cascade that amplifies the fission energy release. This concept just fissions Boron in one step.

Boron has atomic number 5 and Helium has atomic number 2. Any isotope variations would always have the Boron having a nucleus with more nucleons than the Helium. So clearly this is a fission reaction and not a fusion reaction.

If anything then H-1 + B-11 ---> 3 He-4 [excited C*-12 is an intermediate]
It is fusion in the sense that we have C-12 in excited state as an intermediate. Production of this excited C-12 also releases energy.
Then there is a fission of it but some part will radiate gamma and stabilize as ordinary C-12.
I like to call it "thermonuclear fission"
Very comparable situation we have in hydrogen bombs based on Lithium-7 deuteride.
Unstable Be-8 is formed which decays to 2 Hellium-4 nuclei.
Another thermonuclear fusion - fission.
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Re: THE Nuclear Fusion Thread Pt. 3

Unread postby dissident » Sun 23 Feb 2020, 23:31:10

EnergyUnlimited wrote:
dissident wrote:This is not sustained and is not fusion. This is

H + B -> 2 He

The He produced is not cycling back into the reaction and Boron is fissioned in the process. In other words, this is a fancy conventional reactor that is burning some fuel stock in a fancy way. It is not even a standard nuclear reactor that uses a neutron cascade that amplifies the fission energy release. This concept just fissions Boron in one step.

Boron has atomic number 5 and Helium has atomic number 2. Any isotope variations would always have the Boron having a nucleus with more nucleons than the Helium. So clearly this is a fission reaction and not a fusion reaction.

If anything then H-1 + B-11 ---> 3 He-4 [excited C*-12 is an intermediate]
It is fusion in the sense that we have C-12 in excited state as an intermediate. Production of this excited C-12 also releases energy.
Then there is a fission of it but some part will radiate gamma and stabilize as ordinary C-12.
I like to call it "thermonuclear fission"
Very comparable situation we have in hydrogen bombs based on Lithium-7 deuteride.
Unstable Be-8 is formed which decays to 2 Hellium-4 nuclei.
Another thermonuclear fusion - fission.


Thanks for the clarification. This approach requires a plasma temperature about 10 times higher than the Deuterium-Tritium used in tokomaks, hence the need for laser confinement.

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

Smells like a free lunch to me.
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