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PostPosted: Feb 25, 2011 2:40 pm 
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Hat tip to Nuclear Townhall..
Article


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PostPosted: Feb 25, 2011 6:55 pm 
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'The engine of the train will be a small fast breeder reactor'

??Why a fast breeder, for goodness sakes?


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PostPosted: Feb 26, 2011 2:28 pm 
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I told you all that nuclear trains were a good idea!

Why a breeder? Here's why:

A vehicle reactor needs a lot of excess reactivity to cope with the formation of Xenon, a strong neutron absorption poison that occurs naturally in reactors, and crucially, becomes very important when trying to restart them. Stationary power plants cope with Xenon poisoning by staying off for a day or two to let it decay. Vehicles may have to move immediately for safety reasons, so they need to be able to restart at any time.

So, since a fast reactor is needed anyway... A fast breeder just doesn't cost anything extra, in safety or core size. And it will increase the time between fuel changes, lowering service costs. The breeding elements initially act as burnable poisons, lowering reactivity in a new core. As time passes they start to contribute fuel.

There's some evidence that naval nuclear reactors do this: The reactors somehow last for 20 years of more (the service life of most ships) without needing refueling. Also, the first prototype civilian reactor was based on a reactor for aircraft carriers, and was later used in early thorium breeding experiments. It's easy to think that it had to have been designed with breeding in mind in order for those experiments to succeed.


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PostPosted: Feb 27, 2011 2:30 am 
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I see can why they would want this . The Russians do not have many warm water ports. Its a long way from Vladivostok to Moscow. They need to defend Siberia or china will take it in the future.


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PostPosted: Feb 27, 2011 6:52 am 
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Well, now state why you don't want a fast reactor:

A train is a moving vehicle and will therefore have quite an amount of vibrations in the core. Small changes in geometry induce rather significant reactivity changes in fast reactors.

And I doubt it will be a breeder reactor. One should take into account that the website who published the article may have heard fast reactor and thought by himself so it's a breeder...In the past a "Fast Reactors" was often a synonym for "Fast Breeder Reactor"

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Liking All Nuclear Systems, But Looking At Them Through Dark And Critical Glasses.


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PostPosted: Feb 27, 2011 7:21 am 
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The more likely choice is a marine Navy PWR, such as those on submarines and aircraft carriers. They're rugged and withstand vibrations. A small BWR is also an option.


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PostPosted: Feb 27, 2011 8:26 am 
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While it may not be a practical idea for regular service, the part about a mobile power station – like a land-based version of the Sevmash barge with two KLT-40S reactor units – might make sense: you could even have the massive shielding on separate train cars, to be moved into position around the reactor once the unit is on station (with seismic-rated stabilisation “legs” extended and wheels raised OFF the rails….).
Or, one of the train cars could have a big backhoe on it, to dig a hole into which the reactor can be lowered for a period of time -- with the thermodynamic conversion plant remaing on the other train cars. This would be a little like the proposed future lunar base nuke plants (also fast reactors, BTW)


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PostPosted: Feb 28, 2011 4:28 pm 
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I wonder if this is a derivative of the Russian lead-cooled submarine reactor.


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PostPosted: May 16, 2011 4:01 pm 
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Location: Rhinebeck, NY
Some times trains derail or hit other trains or cars at level crossings. Nuclear reactor driven trains is the dumbest idea I have heard in a long time.


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PostPosted: May 17, 2011 2:53 am 
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So far, it is a concept which may lead to a technology demonstration project. It could even be a train carrying a Nuclear Power Plant, and being run by the power it produces rather than a new locomotive concept. It could lead to very welcome design of a nuclear reactor transportable from the factory by train. Russian Nuclear Powered ice-breakers have lead to Floating Power Plants. Russians also have enough land area to run trains on.
Keep a watch for next 5-10 years :?:


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