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PostPosted: May 31, 2014 12:21 pm 
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Lindsay wrote:
jagdish wrote:
Lindsay wrote:
From an efficiency point of view, a steam cycle with double reheat would make much more sense, but the big challenge is the reactivity of sodium with water and steam.

If some salt or lead eutectic were used as the secondary coolant, the risk of sodium-water/steam coolant will be eliminated. That is why I wonder when (not if) it will be done.

When I made that first post that's what I was thinking, keep sodium in the primary loop if it performs better and run Lead-Bismuth Eutectic (LBE) or something chemically non-reactive in the intermediate loop.

I just did a quick search on corrosion resistance to molten lead and 316 SS came up a number of times, this would also be a good material for making steam generators out of from a corrosion/chemical compatibility perspective on the water/steam side. Others may know a lot more about good material choices for LBE, but the secondary coolant doesn't have to be LBE.


Why would you bother using a coolant in a secondary loop that you did not use in the primary because you deemed its technological readiness too low? If you want to understand their choices, you have to stay coherent.


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PostPosted: Jun 01, 2014 2:47 am 
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Sodium continues to be used for fast reactor due to virtually no corrosion. The main reason of the discontinuation of fast reactors is sodium fires, Japan being the latest sufferer. Replacing the secondary sodium greatly reduces the fire hazard as no sodium comes in contact with air or water. LBE does not react with sodium or water and is a safety link. Some salt eutectic could be as good and cost less and the minds should stay open.


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PostPosted: Jun 01, 2014 3:06 am 
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Boris H wrote:
Why would you bother using a coolant in a secondary loop that you did not use in the primary because you deemed its technological readiness too low? If you want to understand their choices, you have to stay coherent.

I might be misunderstanding the point that you're trying to make I haven't deemed the technological readiness of LBE or sodium anything.

The suggestion to use LBE as secondary coolant is to side-step the chemical reactivity issue and associated risk with having sodium on one side of a heat exchanger and high pressure water/steam on the other. If sodium coolant is the reason to do some inefficient never done before power train, why not look at an alternative coolant, run a more efficient power conversion system and make more MW?


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PostPosted: Jan 07, 2015 4:48 pm 
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For those who can read french and are interested by Sodium Fast Reactors, the CEA released nine very interesting documents on the SFR technology ( design, safety, fuel, historical backround, etc... these docs contain some informations about phénix, superphénix and ASTRID ).

It is on this page :

http://www.cea.fr/energie/les-reacteurs-nucleaires-a-caloporteur-sodium

There is also a good topic on neutronics :

http://www.cea.fr/energie/la-neutronique

All the topics are here :

http://www.cea.fr/energie/tous-les-dossiers/%28debut%29/0


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PostPosted: Jun 06, 2016 3:19 pm 
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For those who are interested in the ASTRID project, here are two interesting presentations on the basic features of the reactor.

https://www.iaea.org/NuclearPower/Downloadable/Meetings/2015/2015-06-23-06-24-NPTDS/2-1-2-ASTRID-Roadmap.pdf

https://www.iaea.org/NuclearPower/Downloadable/Meetings/2016/2016-05-16-05-20-NPES/4.0_France_49th-TWG-FR.pdf

The reactor seems quite different from Superphenix (low void effect core, nitrogen turbine, simplification of fuel handling (in particular the suppression of the external intermediate fuel storage tank), etc)


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PostPosted: Jun 07, 2016 5:52 pm 
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Interesting, fab. ASTRID first criticality ~2030. Monju (Japan) is an SFR and having trouble.

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PostPosted: Jun 08, 2016 12:19 pm 
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Quote:
Monju (Japan) is an SFR and having trouble.


Sadly there were a lot of SFRs which have encountered problems (and not only technical problems but administrative and political problems too for example Superphénix). But there were also some which worked well (for example the EBR II, the BN-600 and Phénix).

The conceptors of ASTRID have the experience of all the problems encountered with previous SFRs, so normally ASTRID should work well. The great unknown is the nitrogen turbine which is the biggest innovation (but maybe they will swap it for a conventionnal steam turbine).

But we don't know yet if ASTRID will be built, there are a lot of political opposition.


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PostPosted: Jun 08, 2016 1:56 pm 
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Very well, fab. That moves us back over to:

Board index » Liquid-Halide Reactors » Fluoride Reactor Design

Specifically the merits of the Flibe Energy LFTR design: EPRI publishes tech innovation report on Flibe Energy's LFTR

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PostPosted: Jun 08, 2016 5:01 pm 
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fab wrote:
For those who are interested in the ASTRID project, here are two interesting presentations on the basic features of the reactor.

https://www.iaea.org/NuclearPower/Downloadable/Meetings/2015/2015-06-23-06-24-NPTDS/2-1-2-ASTRID-Roadmap.pdf

https://www.iaea.org/NuclearPower/Downloadable/Meetings/2016/2016-05-16-05-20-NPES/4.0_France_49th-TWG-FR.pdf

The reactor seems quite different from Superphenix (low void effect core, nitrogen turbine, simplification of fuel handling (in particular the suppression of the external intermediate fuel storage tank), etc)


Thanks for the information. The nitrogen turbine seems like a huge development risk to me. What is the largest nitrogen turbine-generator set ever built ? Not in the ballpark of 600 MWe, I guess. Alstom is the partner for the power conversion unit, but now has been acquired (at least the power business) by General Electric, which means that final decisions regarding development are likely to be made in Connecticut, USA and not in Paris or Belfort anymore.

Sad to see that there is very little information about molten salt reactors on the French pages of the CEA. It is only mentioned once or twice as a fourth generation reactor type. All CEA eggs are apparently in the ASTRID basket, which I also regard as a duplication of effort, because these fourth generation SFR types are also being developed in other countries (the new BN-800 is already operating in Russia).

It also remains to be seen how this ASTRID project will progress after the elections in France next year. This ASTRID project is likely to be dead in the water if Hollande and the Socialists are re-elected to government.


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PostPosted: Jun 08, 2016 9:57 pm 
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camiel wrote:
fab wrote:
For those who are interested in the ASTRID project, here are two interesting presentations on the basic features of the reactor.

https://www.iaea.org/NuclearPower/Downloadable/Meetings/2015/2015-06-23-06-24-NPTDS/2-1-2-ASTRID-Roadmap.pdf

https://www.iaea.org/NuclearPower/Downloadable/Meetings/2016/2016-05-16-05-20-NPES/4.0_France_49th-TWG-FR.pdf

The reactor seems quite different from Superphenix (low void effect core, nitrogen turbine, simplification of fuel handling (in particular the suppression of the external intermediate fuel storage tank), etc)


Thanks for the information. The nitrogen turbine seems like a huge development risk to me. What is the largest nitrogen turbine-generator set ever built ? Not in the ballpark of 600 MWe, I guess. Alstom is the partner for the power conversion unit, but now has been acquired (at least the power business) by General Electric, which means that final decisions regarding development are likely to be made in Connecticut, USA and not in Paris or Belfort anymore.

Sad to see that there is very little information about molten salt reactors on the French pages of the CEA. It is only mentioned once or twice as a fourth generation reactor type. All CEA eggs are apparently in the ASTRID basket, which I also regard as a duplication of effort, because these fourth generation SFR types are also being developed in other countries (the new BN-800 is already operating in Russia).

It also remains to be seen how this ASTRID project will progress after the elections in France next year. This ASTRID project is likely to be dead in the water if Hollande and the Socialists are re-elected to government.


Nitrogen turbines are effectively the same as air turbines though right? What's stopping people from simply ordering a lot of frame 7 based rigs and ganging them together? Balance of plant from having multiple turbines would suck, but the turbine costs should go down significantly. At least Rod Adams's felt using conventional aeroderivative turbine designs with the associated data/supply chain was a smarter choice.


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PostPosted: Jun 09, 2016 11:47 am 
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Nitrogen CCGTs? What about the supercritical CO2 Brayton Cycle?

GE doing sCO2 turbine PR

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PostPosted: Jun 09, 2016 3:22 pm 
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Quote:
Alstom is the partner for the power conversion unit, but now has been acquired (at least the power business) by General Electric, which means that final decisions regarding development are likely to be made in Connecticut, USA and not in Paris or Belfort anymore.


If the CEA finances the development I guess they will surely do it.

Quote:
This ASTRID project is likely to be dead in the water if Hollande and the Socialists are re-elected to government.


For now it seems very unlikely that Hollande will be re-elected, it will probably be the nominee of "Les Républicains" (the classical right side party). However even if the right side party wins there will be a lot of opposition against ASTRID, there are a lot of problems right now with the funding of the EPRs at Hinkley Point.

Quote:
Nitrogen turbines are effectively the same as air turbines though right?


As Lindsay said earlier in this thread, this turbine will be quite different from the usual gas turbines. The pressure is much higher than with usual gas turbines and the temperature much lower. Also there is not just the turbine to develop but the entire loop, especially the sodium-nitrogen heat exchangers.

Quote:
All CEA eggs are apparently in the ASTRID basket, which I also regard as a duplication of effort, because these fourth generation SFR types are also being developed in other countries


They already have a lot of experience with SFRs. Taking the MSR path would be like beginning from scratch. And they don't have a lot of financing and time (they want an industrial generation 4 reactor ready before 2040).

But I would also prefer that they work on MSRs or molten salt cooled reactors.

Quote:
Nitrogen CCGTs? What about the supercritical CO2 Brayton Cycle?


Hot liquid sodium reacts chemically with steam and CO2 but not with nitrogen so that is why they want to use nitrogen for ASTRID. It is an important element for the safety demonstration.

However the supercritical CO2 cycle seems very good for molten salt reactors.


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PostPosted: Jun 09, 2016 3:29 pm 
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fab wrote:
Quote:
Nitrogen CCGTs? What about the supercritical CO2 Brayton Cycle?
Hot liquid sodium reacts chemically with steam and CO2 but not with nitrogen so that is why they want to use nitrogen for ASTRID. It is an important element for the safety demonstration.

However the supercritical CO2 cycle seems very good for molten salt reactors.
Ah! Thanks, fab.

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PostPosted: Mar 20, 2017 5:20 pm 
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The ML-1 was a pressurized nitrogen brayton cycle, with a recuperator. And, it had problems because of it.
A once-through atmospheric pressure design appears to be far less risk and was recommended in post-mortems.
https://en.wikipedia.org/wiki/ML-1


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PostPosted: Mar 23, 2017 3:06 am 
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The Indian PFBR is stuck with prototype troubles for last three years. Kudos to Russians for getting their fast reactor working.


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