Nuclear startup Oklo gets thumbs-down from regulators

Re:Nuclear startup Oklo gets thumbs-down from regulators by DennisP on Friday January 14, 2022 @03:42PM (#29940149)

I can tell you know this but just to clarify, sodium and lead don't moderate the neutrons like water does (i.e. slow them down), so you can have a fast reactor, which means you can fission your U238 and transuranics instead of throwing them away as nuclear waste.

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Re:Nuclear startup Oklo gets thumbs-down from regulators by PaulHoule on Friday January 14, 2022 @04:16PM (#29940558)

You can run a water reactor with a much faster spectrum if you have more fuel and less water.

Shippingport was able to breed on the Thorium-U233 cycle.

Plutonium breeding could also be accomplished with a water reactor, possibly with two separate reactors in the fuel cycle to tune up the use of odd and even numbered isotopes. See

https://en.wikipedia.org/wiki/Supercritical_water_reactor

The trouble with it is that water has limited ability to remove heat so you are going to have a large amount of fuel tied up creating a critical mass producing relatively little water. That makes it hard to build up the fuel inventory for a fleet of breeders and economics are even worse than today's water reactors.

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Re:Nuclear startup Oklo gets thumbs-down from regulators by pfdietz on Friday January 14, 2022 @04:01PM (#29940371)

Lead does slow down sufficiently fast neutrons, by inelastic nuclear scattering. But this has a threshold (0.57 MeV); below that energy it hardly affects neutron energy at all.

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