Equation for flux in reflected slab reactor

In summary, the conversation discusses the difficulty of finding a solution for calculating thermal and fast fluxes in the reflector of a critical slab reactor. Suggestions for possible solutions include using a numerical method like Monte Carlo simulation or simplifying the geometry into cylindrical shells.
  • #1
StudioSaturn
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So, I've been at this for a while now. I am using my textbook (Introduction to NE, Lamarsh) and I cannot find a solution to calculate the thermal and fast fluxes in the reflector of a critical slab reactor. I have only been able to find solutions for the spherical shape, even online. As I understand it, the general solution is
upload_2015-6-6_19-0-39.png

And for spherical geometry, the fast flux can be resolved in a finite reflector to be
upload_2015-6-6_19-1-59.png

But what about the slab?
If anyone could point me to a source online, or if you could offer any help here it would be appreciated. I have been able to calculate the thermal and fast fluxes in the core, but the reflector has me stumped. Thanks in advance!
 
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  • #2
These are the equations I used for the core.
For thermal flux in the core:
upload_2015-6-6_19-8-18.png

And to get the fast flux from the thermal flux:
upload_2015-6-6_19-9-37.png

Also, I know that at the reflector-core interface, the fluxes must be continuous, and there is no neutron source term in the reflector. Thanks
 
  • #3


Hi there,

I understand your frustration with not being able to find a solution for calculating thermal and fast fluxes in the reflector of a critical slab reactor. Have you tried looking at other textbooks or online resources? Sometimes different sources can offer different perspectives and approaches to solving problems.

One possible solution could be to use a numerical method such as Monte Carlo simulation to calculate the fluxes in the reflector. This method allows for more complex geometries and can be helpful in cases where analytical solutions are not readily available.

Another approach could be to simplify the slab geometry into a series of cylindrical shells and then use the cylindrical geometry solution to calculate the fluxes. This may not be an exact solution, but it could provide a good approximation.

I hope these suggestions help and good luck with your calculations!
 

FAQ: Equation for flux in reflected slab reactor

1. What is the equation for flux in a reflected slab reactor?

The equation for flux in a reflected slab reactor is given by F(x) = (αD/sinh(αL))(cosh(αx)-cos(αx)), where F(x) is the flux at a distance x from the slab, α is the neutron absorption coefficient, D is the diffusion coefficient, and L is the thickness of the slab.

2. How is the flux affected by the thickness of the slab?

The flux is directly proportional to the thickness of the slab. This means that as the thickness of the slab increases, the flux also increases. However, as the slab becomes thicker, the flux eventually approaches a limiting value.

3. What is the significance of the absorption coefficient in the flux equation?

The absorption coefficient, α, represents the probability that a neutron will be absorbed by the material in the slab. A higher absorption coefficient means that there is a greater chance of neutron absorption, which can decrease the flux in the reactor.

4. Can the flux equation be applied to other reactor geometries?

Yes, the flux equation can be adapted to other reactor geometries, such as cylindrical or spherical geometries. However, the specific form of the equation will vary depending on the geometry of the reactor.

5. How does the flux change in a reflected slab reactor with changing diffusion coefficient?

The flux is directly proportional to the diffusion coefficient, D. This means that as the diffusion coefficient increases, the flux also increases. On the other hand, a decrease in the diffusion coefficient will result in a decrease in flux.

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