Thorium Doubling Time in Fast Reactors

[Ahmed Shaker]

I have done some reading on the utilization of Thorium in fast reactors, but the doubling time for breeding ranges from 20 to 80 years, is there any solid material on the subject? Just curious.

 

[QuantumPion]

Do you have a specific question?

 

[Astronuc]

I have done some reading on the utilization of Thorium in fast reactors, but the doubling time for breeding ranges from 20 to 80 years, is there any solid material on the subject? Just curious.

It's a matter of the magnitude of absorption cross-section as a function of energy. The lower the absorption cross-section, the longer is takes for a given mass/number of fertile nuclei to absorb neutrons, which then initiates the decay process to something hopefully more fissionable. Thermal and epithermal systems have a population of neutrons in the resonance absorption range (1 eV to 3 keV) where the absorption cross-sections can be two or three orders of magnitude greater than those in the MeV range. The thermal energy range below 1 eV has an increasing magnitude as neutron energy decreases.

See - the (n,γ) cross-sections here - http://www.nndc.bnl.gov/sigma/index.jsp?as=232&lib=endfb7.1&nsub=10

http://www-pub.iaea.org/books/IAEABooks/7192/Thorium-Fuel-Cycle-Potential-Benefits-and-Challenges

 

[Ahmed Shaker]

Do you have a specific question?

Not really, just wanted some broad information. But I have all that I need now.