This was discussed on the Energy From Thorium forum It was noted that the fusion/fission hybrid would not be as affordable or as simple as the liquid flouride thorium reactor (LFTR). However, the fusion transmuter hybrid might be available as early as 2012 for $30-40 million in development while a LFTR would take longer. It was noted that it would take 16.5 years for the fusion transmuter to produce Uranium 235 needed. However, if each module only costs $20-30 million then $300 million for ten modules would cut the production time down to 1.65 years. Nuclear reprocessing plants currently are very expensive. $20 billion for the Japanese facility (Rokkasho). Five hundred fusion transmuter modules would cost about $15 billion (and the price could go down with factory mass production).
In the latest Helion Energy presentation they discuss 50 fusion engines being able to burn or transmute the entire stockpile of nuclear waste in 20 years. The Fusion engine is an upgrade of the 2012 system.
50 times $100 million – $5 billion is far cheaper than waste repositories or reprocessing.
If the 2012 unit is not the fully ready thing, based on the timelines it could be 2-4 years more to get to a useful commercial system.
The $2.5 million proposal looks like ARPA-E size or government stimulus fundable thing. Plus U of Washington gets enough in its regular physics budget to pay for it.
Still faster than development of a LFTR.
Potentially faster and cheaper than building a repository. (especially with regulatory and political issues)
Just the transmutation part even without the dedicated fission reactors would be worthwhile. I think they could transmute fuel for some of the regular reactors now to use
The Lawrence Livermore (LIFE hybrid) and other fusion fission hybrid systems were all talking about one billion dollar plus development and 2020-2030 as timeframes for when the main development would be occuring at the earliest.
Motivation for CTF (Component Test Facility) based on the FRC (Field Reversed configuration)
Criteria for Component Test Facility:
(1) Provide an environment close to the fusion reactor
(a) On the smallest physical scale (cost and timeliness)
(b) With the simplest configuration (cost and ease of use)
(2) It should be capable of evaluating the full tritium fuel cycle.
(3) It should allow for easy diverter access for evaluation of a range of materials evaluation
Magneto-kinetic Compression of FRC plasmoids
Fusion Power Density scales as β2B4
(1) The FRC has the highest of all fusion plasmas ( ~ 0.8-0.9)
(2) Compression and burn occurs in a simple linear geometry at highest
possible B consistent with pulsed solenoidal coil (Bz ~15-20 T)
(3) D-T fusion neutron generation provides more realistic test for
materials and tritium breeding
(4) Diverter outside blanket and remote from burn chamber
The pulsed FRC based CTF:
(1) Reduces by orders of magnitude the scale and complexity involved in a CTF based on a spallation source, ST or tokamak
(2) Provides for a vastly lower cost, risk and a much shorter timescale for implementation
(3) Can address both material exposure issues in blanket as well as diverters.
(4) Can address crucial Tritium fueling concerns –
(I) Inventory, (II) Production, (III) Processing, and (IV) Recovery
All are without resolution
All represent potential show-stoppers for DT fusion.
(5) Can be further developed to contribute to energy production in the near term
(I) fissile/fusile breeder
(II) Waste transmutation/burner
In this you will find that in addition to the fusion neutron source supplying a small percentage of makeup neutrons one must also:
separate the actinides from the spent fuel
develop a lead cooled, fluid reactor
develop a first wall material that can survive being in the center of a fast reactor
develop on-line fission product removal.
All these things are not included in Helion fusion engine development program and in fact will require more development work than LFTR. LFTR has the advantage of being similar to MSRE and hence has much development work already completed. I don’t believe anyone has built a lead cooled, fluid fuel reactor yet at any size.
One of the biggest challenges with LFTR is the lifetime of the first wall. In our case, that first wall is on the outer perimeter of the reactor chamber where it sees around 5% of the neutrons. In the reactor proposed in the paper above the first wall is between the fusion and fission reactors. It sees the full neutron flux from the fusion machine (and those are very fast so they more damaging to the wall). In addition it is near the heart of the fission reactor where it will see a large fission neutron flux.
This is not to say he should stop work. Solving the energy problem is a very high value proposition worthy of several parallel efforts. But you will not have a power producing reactor for $40M using this approach. He hopes to build a fusion engine with break even power for this money scaled to supply 1/20th the neutrons used in a 1GWe reactor.
You still have the expense of developing the fission reactor – that is not included in any of his costs. The fission reactor is the one that supplies 95% of the neutrons and all of the output power available to sell.
From Axil (how the first wall problem can be avoided with intermittent operation and easy and frequent swaps of the first wall):
If aneutronic B11-H fusion is not practical from either a technical or economic standpoint anytime in the near future, then D-T fusion is best served by a fusion/fission hybrid concept, and the Hilion reactor topology is well positioned for this approach.
Any big project should be developed in well thought out, mutually supportive and orchestrated phases. The thorium fusion hybrid should conform to this type of development strategy. The first phase should be the development of a U233 fuel factory. The first market would be existing Light Water Reactors and the new AHTR pebble reactors.
The price for the U233 would be well below the current U235 equivalent price. I think that such a fusion/fission fuel factory is very price competitive and is capable of producing U233 very well below this current $70 lbs yellowcake equivalent. The price of yellow cake has varied from $15 to $137 per pound recently and currently it is about $70 per pound.
The best type of fusion/fission hybrid has a very small zone of fusion preferably a point source. The Hilion reactor has this very important feature and because of the small size of the fusion zone it facilitates an all inclosing blanket with almost perfect closure. Because of the ideal efficiency of its almost perfect liquid blanket envelope, I can see this type of subcritical reactor producing about 5500 kgs of pure U232/U233 per year. Very few neutrons would be wasted. Beryllium in the blanket would almost double the production of the fusion neutron flux. To maximize U233 production, no lithium should be included in the blanket. Tritium would come from the waste flow of its dependent parasitic fission reactors; its customers.
The reactor does not need heat exchangers of turboelectric generators; it can dump the heat produced by fusion (typically 10 megawatts) to the air so a thermal power circuit wound not need to be developed or deployed. Because it is subcritical, it would not need a containment structure either.
If the protactinium is removed from the liquid fluoride beryllium/thorium blanket through on-line blanket salt reprocessing immediately after its creation, no fission heat would be produced by U233 fission.
Since this hybrid does not need to produce electric power or connect to the grid, this hybrid can operate intermittingly to allow frequent change out of its first wall. Such a diamond pipe can be replaced in a matter of hours. A coating of lithium hydride on the inside of this first wall diamond pipe might greatly reduce alpha particle damage.
I believe that this is the development strategy currently envisioned for the Helion fusion engine development program.
If the U233 can be produced with a 1% or greater U232 content, then no U238 denaturing would be required by IAEA rules. This highly enriched and proliferation proof U232/U233 nuclear fuel would make light water reactors and AHTR very clean and eliminate the waste problem associated with the uranium fuel cycle. This alone would be a big selling point for the thorium/fusion hybrid and get the thorium fuel cycle off at a run.
Brian Wang is a Futurist Thought Leader and a popular Science blogger with 1 million readers per month. His blog Nextbigfuture.com is ranked #1 Science News Blog. It covers many disruptive technology and trends including Space, Robotics, Artificial Intelligence, Medicine, Anti-aging Biotechnology, and Nanotechnology.
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