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tahanson43206

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Fusion Reactor Design: Produce Tritium - Global Energy Storage Market

This topic is inspired by an observation of Calliban, that fusion (when it is achieved) will be able to produce Tritium in abundance.

Tritium appears to be a useful material for safely delivering heat and small amounts of electricity to billions of Earth citizens, as an alternative to fossil fuel.

The first post in this new topic will be a copy of a post by Calliban in the Fission topic for Tritium production.

(th)

tahanson43206

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Registered: 2018-04-27

Posts: 18,169

Re: Fusion Reactor Design: Produce Tritium - Global Energy Storage Market

The following is a quote from the Fission topic devoted to production of Tritium for the home heating and power market.

I note that this post is about consumption of Tritium, so some adjustment is needed, to adapt the post to this new topic.

TH, world lithium mining is over 100,000 tonnes of metal per year.
https://www.reuters.com/markets/commodi … 023-04-21/

A 1GWe fusion reactor, will consume ~60kg tritium per year, requiring some 120kg of lithium.  If we powered the entire world in this way, it would consume <1% of lithium mined at present.  And in a fusion-fission hybrid system, the fusion reaction is providing the neutrons rather than the energy itself.  So we don't need anywhere near 1% of present lithium mining to power the world in this way.  Lithium is not a limited resource as a nuclear fuel.  It is in short supply because idiots need megatonnes of the stuff to produce batteries.  But in fusion reactors, a few hundred tonnes a year woukd power the world!

(th)

Calliban

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From: Northern England, UK

Registered: 2019-08-18

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Re: Fusion Reactor Design: Produce Tritium - Global Energy Storage Market

I think excess tritium breeding would only work in a fusion-fission hybrid system.  A pure fusion system doesn't have enough spare neutrons for this sort of scheme to work.  Within a hybrid system, we surround the fusion reaction chamber with rods containing uranium-zirconium alloy.  The fast 14-MeV neutrons produced by each fusion reaction will fast-fission the uranium, producing up to five additional neutrons.  Some of these will cause secondary fission, but most will be absorbed by uranium-238, which decays into Pu-239.  So for each fusion event that takes place, we can expect to generate 10x more power from direct fission and perhaps 4 Pu-239 atoms with which to make nuclear fuel.  So for each 17.6MeV of fusion energy we get ~200MeV of direct fission energy yield and enough plutonium to yield 800MeV in downstream reactors.

If plutonium is burned in lithium cooled fast reactors, each fission will yield ~3 neutrons.  So four plutonium atoms will yield a total of 12 neutrons, some four of which are used to sustain fission.  The other eight are available to support tritium breeding in the lithium coolant.  If all of them are absorbed in lithium 6 or lithium 7, we get 8 tritium atoms from each initial fusion event.  At least one tritium atom is needed to keep the fusion reaction going.  But a maximum of seven additional couod be available for other uses.  Due to neutron losses and tritium decay, we can expect lower yields than this.  But the overall multiplication could still be substantial.

Last edited by Calliban (2024-01-03 12:40:05)

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"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

tahanson43206

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Registered: 2018-04-27

Posts: 18,169

Re: Fusion Reactor Design: Produce Tritium - Global Energy Storage Market

For Calliban re #3

Thank you for taking up the opportunity this new topic offers ...

You are currently the only member of the forum qualified to speak to the topic with authority.

Our members are invited to contribute links to high quality related references. Please include text explaining why the link is worth opening.

In addition, we (the forum) are happy to bring in new members to join Calliban in developing this (or any) topic.

Please see the Recruiting topic for procedure.

(th)

tahanson43206

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Registered: 2018-04-27

Posts: 18,169

Re: Fusion Reactor Design: Produce Tritium - Global Energy Storage Market

We have three topics that contain "tritium" in the title:

Tritium to Helium-3 Nuclear Battery by tahanson43206
Science, Technology, and Astronomy    20    2024-01-31 19:09:13 by SpaceNut
Fission Reactor Design to produce Tritium via Desalination Market by tahanson43206
Science, Technology, and Astronomy    17    2024-01-31 06:33:06 by Calliban
Fusion Reactor Design: Produce Tritium - Global Energy Storage Market by tahanson43206
Science, Technology, and Astronomy    3    2024-01-03 15:17:28 by tahanson43206

The method of production of Tritium that has come into view in May of 2024, is treatment of Thorium with a particle accelerator.

Thus, the process would consume Thorium and produce Tritium, and (if I understand the process correctly) it would cover it's own energy costs.

In short, (again if I understand the process which is NOT guaranteed) we would be transmuting a material of limited value into a product with great value, and having to add NO fossil fuel to achieve the objective.

(th)

Calliban

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From: Northern England, UK

Registered: 2019-08-18

Posts: 3,578

Re: Fusion Reactor Design: Produce Tritium - Global Energy Storage Market

Yes, it could work.  The most obvious way would be to use 233U as a spallation target.  That way you get at least one fission even in the target, per spallation neutron.  The secondary fission neutrons would them breed enough 233U in a surrounding thorium blanket, to replace the atoms fissioned in the spallation target.  This gives us somewhere between 1 and 2 spare neutrons that can be used to breed tritium.  The easiest way of doing this is to use molten lithium to cool the spallation target and thorium blanket.  The facility should generate twice as much power as needed to run the accelerator, with the balance being sold to the grid.  The tritium would be a byproduct.  You can tweak the design to produce more power or more tritium by adjusting the volume fraction of coolant and fuel.

Last edited by Calliban (2024-05-28 07:30:59)

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"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."

tahanson43206

Moderator

Registered: 2018-04-27

Posts: 18,169

Re: Fusion Reactor Design: Produce Tritium - Global Energy Storage Market

For Calliban re #6

Thank you for taking another look at the transmutation idea.... I get the impression that substituting 233U as the target for the particle beam would improve performance of the system.  The tritium I am looking for would be the deliverable.  The ability of the system to pay for itself is a nice surprise.

However, I am wondering about the abundance of 233U compared to 238U and 235U.

I asked Google and learned about 234U which I did not realize is a naturally occurring isotope.

Google quickly explained that 233U is produced from Thorium 232

OK ... multiple steps are involved, but Thorium is the key ingredient.

I'm now wondering how much Tritium is produced per unit of Thorium?

Are there other daughter products that are useful, or on the other hand, worrisome?

Is it possible to imagine a mass production facility on Earth that yields many tons of Tritium?

Tritium is, as pointed out in other (related) topics, and potentially benign energy delivery device for the mass market.

(th)

Calliban

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From: Northern England, UK

Registered: 2019-08-18

Posts: 3,578

Re: Fusion Reactor Design: Produce Tritium - Global Energy Storage Market

Each fission event produces 2.5 neutrons.  At least one neutron is needed to transmute another 232Th atom into 233U.  Of the 1.5 neutrons remaining, a proportion will cause another fission within the 233U.  Others will leak out into the blanket.  So in a well designed system you could get up to 2 atoms of tritium for each thorium atom transmuted into 233U and fissioned.  Using a plutonium or other heavy actinide spallation target may give you even better results, as these nuclides will produce more neutrons when they fission.

Tritium is indeed a potentially valuable product of this process.  For all the hype around aneutronic fusion, tritium is a lot more useful than He-3 precisely because it does produce high energy neutrons.  Those neutrons can be used for a lot of things, like driving fast-fission or transmuting one element into another.  This makes tritium a much more valuable product than He-3.  As you have probably realised by now, the rate at which we can produce transmutation products using nuclear reactions is constrained by the number of spare neutrons we are able to generate.

Last edited by Calliban (2024-05-28 08:10:26)

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"Plan and prepare for every possibility, and you will never act. It is nobler to have courage as we stumble into half the things we fear than to analyse every possible obstacle and begin nothing. Great things are achieved by embracing great dangers."