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 Post subject: RBMK Conversion?
PostPosted: Jul 04, 2014 11:54 am 
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There are a number of closed and about to be closed RBMK reactors out there. Seems they might be suitable for DMSR conversion. Remove the fuel rods and water pipes, replace with Hastelloy piping and run the DMS fuel salt thru that piping. Use a superheated steam boiler and the RoP remains the same.

Thoughts?

The first thought of mine is that their notorious lack of a containment vessel becomes effectively immaterial.

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 Post subject: Re: RBMK Conversion?
PostPosted: Jul 04, 2014 4:13 pm 
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Hastelloy-N is utterly unsuitable as a cladding/piping material in the presence of a neutron flux.


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 Post subject: Re: RBMK Conversion?
PostPosted: Jul 05, 2014 2:08 am 
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Ok, thanks for the reminder. What would you suggest instead?

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 Post subject: Re: RBMK Conversion?
PostPosted: Jul 05, 2014 12:43 pm 
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I would never attempt the conversion.


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 Post subject: Re: RBMK Conversion?
PostPosted: Jul 05, 2014 6:23 pm 
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Like Kirk said, converting old equipment often costs much more than starting with a clean sheet. In the case of RBMK plants it’s 50 year old buildings full of 50 year old turbines, switch gear, and plumbing would have to be replaced with modern equipment. It would be most worthwhile to bulldoze all building structures leaving only the transformers, transmission lines, and perimeter fences. A new LFTR plant would then be built. This would leave a modern facility with lots of room for expansion in the future.

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 Post subject: Re: RBMK Conversion?
PostPosted: Jul 06, 2014 1:51 am 
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Neither the former German nuclear research (were) nor the Russian favor the concept of molten salt reactors. They are very sceptical concerning non-solved corrosion challenges and complex reprocessing. The Russians are very much in favor of natrium and LBE cooled fast reactors.

The Russians have the big advantage that they does not see ecology as a religion and they see nuclear accidents and nuclear waste somehow realistic without fiction stories. Their regulations allows them to design and make reactors for reasonable costs. While in Europe and North America any small reactor will become killed by the costs of licence application, certifications, tests and documentation the Russians could build as well small reactors for reasonable costs.

If you see their projects as the BN series and the SVBR and BREST series they are quite ahead in making realistic quite economic metal cooled reactors. In opposite to other nations they manage to realize them.


If I have an (optimistic) view in the future lets say 50 years ahead .......

A molten salt reactor reactor requires a very complex fuel reprocessing or at least some treatment. Thus such a reactor will need to be more than 1000 or 2000MW to be competitive vs. coal, or a LWR.

A SVBR can be quite compact with 100 or 200 MWth power. Such a reactor could serve to drive big ships on long routes. It could serve in mines and chemical plants.

From my point of view these technologies are complementary. Molten salt reactors as large plants to generate base load electricity and small metal cooled reactors for application away from the large grids.

Holger


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 Post subject: Re: RBMK Conversion?
PostPosted: Jul 06, 2014 2:36 am 
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SVBR appears to be a good technology. It could use Th-Pu or Th-U233 fuel when such fuels are available. A blanket could be added in the initial reactors to create these fissile isotopes.
MSR should only be proposed with a sweetener of a waste burner. Chloride MSR with water in tube as coolant with minor moderation effect could be an economical design. It would be more economical than the Transatomic design.
Graphite of the RBMK should be best avoided.


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 Post subject: Re: RBMK Conversion?
PostPosted: Jul 06, 2014 1:57 pm 
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Well Jagdish....The fast molten salt designs MSFR and MCFR have usually a breeding ratio > 1 . The SVBR has a breeding ratio of perhaps 0.9.

That means that large fast reactors used to generate electricity could breed the fuel for the smaller reactors used for large ships, mines, chemical plants....

As U -> Pu seems to me the more suitable fuel for fast reactors it is most probably spare plutonium that could be available for this purpose.

Holger


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 Post subject: Re: RBMK Conversion?
PostPosted: Jul 06, 2014 10:38 pm 
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MCFR can be introduced as a waste burner but will turn to a useful contraption with pyro-processing. It will create fissile to recycle all of recovered uranium and last for centuries. Just keep to a simple, economic design.
If the products of reprocessing are converted to nitride or other solid fuel, it can fuel SVBR type reactors too. Thorium could come in handy in waste burners for adding superior fissile U-233 from irradiation but may not be essential.


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 Post subject: Re: RBMK Conversion?
PostPosted: Jul 07, 2014 11:17 am 
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KitemanSA wrote:
Remove the fuel rods and water pipes, replace with Hastelloy piping and run the DMS fuel salt thru that piping. Use a superheated steam boiler and the RoP remains the same.

Not a bad idea.
It's true that Hastelloy piping would absorb far too much neutrons.
RBMKs are in some sense a graphite-equivalent of Candu reactors: They use zircalloy pressure tubes in which fuel bundles are loaded.
You can't use zircalloy with fluoride salts, so the pipes would need to be some form of C-SiC or graphite composite.
If anybody could do such a RBMK conversion, the Russians certainly could.


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 Post subject: Re: RBMK Conversion?
PostPosted: Jul 08, 2014 3:13 am 
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Russians have their BN series series, SVBR and BREST. They could recycle all their used fuel and export nuclear technology and fuel. They are already in the lead.
They may not be interested in the MSR till they find a technology where they can lead.


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 Post subject: Re: RBMK Conversion?
PostPosted: Jul 27, 2014 1:00 am 
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Conversions rarely stack up, too many compromises on performance and too many costs. Better to demo the existing plant and start over as a brownfield development on the same site. Better still, build the new plant next door and then demo the old plant when you're ready, leaving enough room for the next one.


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 Post subject: Re: RBMK Conversion?
PostPosted: Jul 27, 2014 4:43 am 
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jaro wrote:
KitemanSA wrote:
Remove the fuel rods and water pipes, replace with Hastelloy piping and run the DMS fuel salt thru that piping. Use a superheated steam boiler and the RoP remains the same.

Not a bad idea.
It's true that Hastelloy piping would absorb far too much neutrons.
RBMKs are in some sense a graphite-equivalent of Candu reactors: They use zircalloy pressure tubes in which fuel bundles are loaded.
You can't use zircalloy with fluoride salts, so the pipes would need to be some form of C-SiC or graphite composite.
If anybody could do such a RBMK conversion, the Russians certainly could.



at teac3 Charles Holden presented a reactor using hastelloy cladding, and from the images he presented there was a lot of hastelloy versus fuel salt.

http://www.youtube.com/watch?v=ZbtVk8r6-3U

so, should I udnerstand that his design is a no go?

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 Post subject: Re: RBMK Conversion?
PostPosted: Jul 27, 2014 2:11 pm 
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PebbleMaster wrote:
at teac3 Charles Holden presented a reactor using hastelloy cladding, and from the images he presented there was a lot of hastelloy versus fuel salt.

http://www.youtube.com/watch?v=ZbtVk8r6-3U

so, should I udnerstand that his design is a no go?

Correct.


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 Post subject: Re: RBMK Conversion?
PostPosted: Jul 31, 2014 12:09 am 
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Even the Russians build and export mainly their VVER.


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