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The Pebble Bed Reactor

Marauder
Posts: 3,271
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2/15/2012 9:51:53 PM
Posted: 4 years ago
I want to hear all your thoughts on the helium gas cooled rather than water cooled nuclear reactor.

Its called a pebble bed reactor because the uranium is kept in tiny carbon spheres spread out in a tennis ball size graphite 'pebble'
the bed full of pebbles has the gas blown through it absorbing the heat and transferring it, pebbles that are spent and cant be reused are taken out and disposed of.

should things go wrong, it naturally 'shuts down' rather than 'melts down'

I think it has all the assets of normal nuclear reactors and and removes a lot of the problems and that this should be looked into further. http://www.ecogeek.org...
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Mimshot
Posts: 275
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2/17/2012 9:56:41 AM
Posted: 4 years ago
At 2/15/2012 9:51:53 PM, Marauder wrote:
I want to hear all your thoughts on the helium gas cooled rather than water cooled nuclear reactor.
Helium is harder to contain that water or steam.

Its called a pebble bed reactor because the uranium is kept in tiny carbon spheres spread out in a tennis ball size graphite 'pebble'
This increases the volume and mass of the spent fuel by ~100 fold.

the bed full of pebbles has the gas blown through it absorbing the heat and transferring it, pebbles that are spent and cant be reused are taken out and disposed of.

should things go wrong, it naturally 'shuts down' rather than 'melts down'
No, it doesn't shut down. It continues running at something the proponents call 'idle'. Basically this means as it heats up, criticality falls and it reaches c=1.0 at a temperature below the melt-down temp. The reactor will stay 'hot' until it has run out of fuel.

I think it has all the assets of normal nuclear reactors and and removes a lot of the problems and that this should be looked into further. http://www.ecogeek.org...
Modern, properly designed PWRs are safe and should be expanded. Pebble-beds are an interesting idea but have many drawbacks.
Mimshot: I support the 1956 Republican platform
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DirkBergurk
Posts: 32
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2/21/2012 9:54:11 PM
Posted: 4 years ago
At 2/17/2012 9:56:41 AM, Mimshot wrote:
Helium is harder to contain that water or steam.

So? It also creates a more efficient power plant.

This increases the volume and mass of the spent fuel by ~100 fold.

Sure it has more waste by volume, but ~100? ~100 fold compared to what? For what size reactor? Source? In any case, the extra waste would not be a problem if we would just move passed this fear of reprocessing our fuel.

No, it doesn't shut down. It continues running at something the proponents call 'idle'. Basically this means as it heats up, criticality falls and it reaches c=1.0 at a temperature below the melt-down temp. The reactor will stay 'hot' until it has run out of fuel.

Que? Are you are saying that the operators do not have a mechanism to shut down the reaction? Control rods are used as in all reactors. The point is that it has such a strong negative feedback at high temperatures, it is not possible for the reactor to suffer damage in loss of coolant accidents. That is, the power decreases naturally such that natural circulation is all that is needed to cool the reactor.
lewis20
Posts: 5,093
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2/22/2012 8:34:05 PM
Posted: 4 years ago
so it can't melt down because parts of fissionable material material per part of carbon control ratio isn't enough for a meltdown? why didn't we do this from the beginning?
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