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PostPosted: Apr 06, 2013 11:11 am 
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Latest patent application filed by Transatomic

http://www.faqs.org/patents/app/20130083878

Revised / expanded team members (new connection to INL; ex-Westinghouse guy)

http://transatomicpower.com/team.php

The patent application is overbroad as Lars observed.

Who knows if the intent of filing this way is seriously meant to capture IP that would obstruct competitive work in this area -- the reason I checked the team link on Transatomic's website was to remind myself about e-Ink guy, his personal history likely quite prominent in his role at TransAtomic.

I appreciate getting the patent app into the open sooner, not later, from Transatomic and anyone else with credible designs, as this might help constrain ambitions for IP capture in Shanghai


Last edited by MSJ on Apr 06, 2013 12:07 pm, edited 1 time in total.

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PostPosted: Apr 06, 2013 11:43 am 
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From the patent application it looks like they are trying to squeeze out some additional burnup of spent fuel by providing better moderation (using deuterium) than LWRs - a concept similar to using an CANDU to burn up some of the fissile left behind in LWR spent fuel.

So, not a (iso)breeder, a modest step in terms of fuel cycle but a big step if they actually built something. They talk about using graphite as cladding to protect the hydride.

The patent claim seems to try to cover the world of molten salt reactors - so I hope the examiner trims their sails rather dramatically and limits them to the Zr-hydride as a moderator as their claim to something new.


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PostPosted: Apr 06, 2013 1:18 pm 
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To the best of my knowledge, hydrides are not stable at the temperatures of an MSR. The hydrogen dissociates to H2 gas and diffuses out of whatever element is attempting to contain it.

I realized the other day that H2 is a kind of salt--a mixture of an alkali metal (hydrogen) with a halogen (hydrogen). Nature is clever.


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PostPosted: Apr 07, 2013 1:05 am 
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Details of the patent are a disappointment. To burnout the SNF, you need to concentrate the fissile material and burn it in a fast reactor. It could use solid, or preferably liquid fuel.
Filling a PWR with Heavy water in the reactor vessel and primary circuit and getting more power from the spent fuel may be a more feasible solution.


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PostPosted: Apr 07, 2013 2:24 am 
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Kirk Sorensen wrote:
I realized the other day that H2 is a kind of salt--a mixture of an alkali metal (hydrogen) with a halogen (hydrogen). Nature is clever.


H2 has self associative behaviour, like nitrogen, but that doesn't make it a salt. Hydrogen is above the alkali metal row but it's not actually an alkali metal. It's more in common with carbon than the alkalis. With hydrogen being neither metal nor halogen, it can't make salts. That would require addition of metal to displace hydrogen and make a salt.


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PostPosted: Apr 07, 2013 7:26 am 
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Kirk Sorensen wrote:
To the best of my knowledge, hydrides are not stable at the temperatures of an MSR. The hydrogen dissociates to H2 gas and diffuses out of whatever element is attempting to contain it.


That's essentially true if the cover gas includes oxygen or nitrogen or carbon,
because the most hydrogen-loving metals -- which include zirconium, hafnium,
tantalum, lanthanides -- are also exceptionally strong oxide, nitride, and carbide formers.

But TRIGA reactors include ZrH1.x right in the fuel if I recall correctly,
and Doppler broadening ends their fission pulses at temperatures
well below where the 'x' would begin to decline. So if the cover gas is free
of stronger electrophiles, and it is acceptable for it to contain
0.1 mole percent H2 or more, ZrH2 and HfH2 can serve.

http://inis.iaea.org/search/search.aspx ... N:42097777

_________________
--- G. R. L. Cowan, former hydrogen-energy fan
Oxygen expands around B fire, car goes


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PostPosted: Apr 07, 2013 9:42 am 
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GRLCowan wrote:
Kirk Sorensen wrote:
To the best of my knowledge, hydrides are not stable at the temperatures of an MSR. The hydrogen dissociates to H2 gas and diffuses out of whatever element is attempting to contain it.


That's essentially true if the cover gas includes oxygen or nitrogen or carbon,
because the most hydrogen-loving metals -- which include zirconium, hafnium,
tantalum, lanthanides -- are also exceptionally strong oxide, nitride, and carbide formers.

But TRIGA reactors include ZrH1.x right in the fuel if I recall correctly,
and Doppler broadening ends their fission pulses at temperatures
well below where the 'x' would begin to decline. So if the cover gas is free
of stronger electrophiles, and it is acceptable for it to contain
0.1 mole percent H2 or more, ZrH2 and HfH2 can serve.

http://inis.iaea.org/search/search.aspx ... N:42097777


TRIGA operates at very low temperature, which is why it works so well. Metal hydrides with useful neutronic properties are all unstable at elevated temperature - even in pure helium environment. The molecule will just thermolyse and the hydrogen vents out to someplace you don't want it to go. There are good reasons why Hyperion's original idea was abandoned.

Also keep in mind that the fluoride of zirconium is much more stable than its hydride.


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PostPosted: Apr 08, 2013 12:33 pm 
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Lars wrote:
From the patent application it looks like they are trying to squeeze out some additional burnup of spent fuel by providing better moderation (using deuterium) than LWRs - a concept similar to using an CANDU to burn up some of the fissile left behind in LWR spent fuel.

So, not a (iso)breeder, a modest step in terms of fuel cycle but a big step if they actually built something. They talk about using graphite as cladding to protect the hydride.

The patent claim seems to try to cover the world of molten salt reactors - so I hope the examiner trims their sails rather dramatically and limits them to the Zr-hydride as a moderator as their claim to something new.



This discussion really should be started again on its own thread.

I can't see Zirconium Deuteride as having any advantage, you'd need just about as much bulk as graphite (if not more) and for every 1.6 atoms of nice deuterium you are adding a quite absorbing atom of Zr. Zirconium Hydride does give a denser moderator than graphite but far poorer moderating ratio and that would be just first on the list of issues. I'd be pretty shocked if they didn't need to clad it and if you are going to clad, might as well go with better moderators like Be or BeO (like the Aircraft Reactor Experiment).

Their claims do seem to be entirely focused on hydrides and deuterides except for the strange claim 82 where they claim to have invented the idea of using spent fuel in molten salt reactors.

David L.


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PostPosted: Apr 08, 2013 1:10 pm 
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David wrote:
This discussion really should be started again on its own thread.


Agreed and done.


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PostPosted: Apr 08, 2013 6:36 pm 
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From page 84 of ORNL-2157 (December 1956):

Quote:
HYDRIDE-MODERATED CIRCULATING-FUEL REACTOR

An alternative design now being studied includes the use of a somewhat more effective moderator in the core, such as the hydrides of zirconium or yttrium, than the graphite and beryllium oxide moderators discussed above. The hydride moderators would reduce the dependence of the reactor on its reflector for moderation and would introduce the possibility of using a heavy, material, such as nickel or copper, for the reflector. These materials have unusually large removal cross sections for fast neutrons, as given above, and are far more effective as gamma-ray absorbers than the moderating materials usually used as reflectors. Thus a significant portion of the gamma-ray shield might be placed immediately around the core, where its volume would be greatly reduced. While the density of radiation heating in a metal reflector would be greater than in a beryllium oxide reflector, the allowable stress would be much greater also, so that fewer cooling holes would be required for a nickel than for a beryllium oxide reflector. In the case of copper, the conductivity is so high that cooling might be required only at the inner and outer surfaces of an 8-in.-thick reflector.

Preliminary calculations indicate that a few thousand pounds in shield weight might be saved by using a dense metal reflector. The effect of capture gamma rays in the reflector, as well as the activation of NaK in the heat exchanger, remain to be determined. Further calculations of fuel concentrations in reactors with metal reflectors are also required.


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PostPosted: Apr 08, 2013 11:32 pm 
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Here's a hint on how they plan to keep the zirconium hydride from decomposing:

Quote:
[0124]
In the modeled case, the fuel-salt mixture flows both inside and outside the annular rod. In examples in which the fuel salt flows on the outside and a different, non-radioactive coolant on the inside of each rod, the purpose of the non-radioactive coolant would be to keep the annular rod from overheating. Such an approach could be used if the annular rod were made of a material that could not be allowed to get hotter than a certain maximum temperature.

....hopefully the coolant is heavy water :P


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PostPosted: Apr 10, 2013 4:56 pm 
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Interesting. There is a Mark Massie included on a paper with Charles W. Forsberg on the preliminary program for the 2013 ANS Annual meeting in November. The topic is "Plant Design Lessons Learned from Sodium and Molten-Salt Reactors Applicable to Fluoride-Salt-Cooled High-Temperature Test Reactor (FHTR), Mark Edward Massie, Charles W. Forsberg (MIT)." It sounds like the graphite pebbles cooled by molten salt based on the other similar papers.


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PostPosted: Apr 11, 2013 4:40 am 
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So when the WAMSR folks say that uranium dioxide SNF pellets will simply be dumped into fluoride salt and dissolved, how much FOOF is that likely to create ?

http://pipeline.corante.com/archives/20 ... uoride.php

....and what about simply exposing fluoride salts at 700 degrees to air ? ...no FOOF ?


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PostPosted: Apr 11, 2013 9:02 am 
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jaro wrote:
Here's a hint on how they plan to keep the zirconium hydride from decomposing:

Quote:
[0124]
In the modeled case, the fuel-salt mixture flows both inside and outside the annular rod. In examples in which the fuel salt flows on the outside and a different, non-radioactive coolant on the inside of each rod, the purpose of the non-radioactive coolant would be to keep the annular rod from overheating. Such an approach could be used if the annular rod were made of a material that could not be allowed to get hotter than a certain maximum temperature.

....hopefully the coolant is heavy water :P


So you're back into serious safety territory with loss of coolant, hydrogen evolution, steam pressurization accidents. Vbad.


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PostPosted: Apr 11, 2013 10:31 am 
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Kirk Sorensen wrote:
From page 84 of ORNL-2157 (December 1956):

Quote:
HYDRIDE-MODERATED CIRCULATING-FUEL REACTOR

An alternative design now being studied includes the use of a somewhat more effective moderator in the core, such as the hydrides of zirconium or yttrium, than the graphite and beryllium oxide moderators discussed above. The hydride moderators would reduce the dependence of the reactor on its reflector for moderation and would introduce the possibility of using a heavy, material, such as nickel or copper, for the reflector. These materials have unusually large removal cross sections for fast neutrons, as given above, and are far more effective as gamma-ray absorbers than the moderating materials usually used as reflectors. Thus a significant portion of the gamma-ray shield might be placed immediately around the core, where its volume would be greatly reduced. While the density of radiation heating in a metal reflector would be greater than in a beryllium oxide reflector, the allowable stress would be much greater also, so that fewer cooling holes would be required for a nickel than for a beryllium oxide reflector. In the case of copper, the conductivity is so high that cooling might be required only at the inner and outer surfaces of an 8-in.-thick reflector.

Preliminary calculations indicate that a few thousand pounds in shield weight might be saved by using a dense metal reflector. The effect of capture gamma rays in the reflector, as well as the activation of NaK in the heat exchanger, remain to be determined. Further calculations of fuel concentrations in reactors with metal reflectors are also required.


This prior art seems to invalidate most of their claims with the possible exception of some minor dependent claims (e.g. moderator cooling structure).

IANAPA but I have written several.


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