Integral Neutron Flux: Getting Results with MCNP - Juan Galicia-Aragon

[Juan Aragon]

Hello everyone

I am trying to obtain the integral neutron flux based on the results obtained with MCNP (neutron spectrum calculation) for each energy bin (51 neutron energy bins). I have seen in many papers the calculation of the differential neutron flux multiplying the neutron flux results of MCNP by each energy bin; however, I can not figure how to obtain the integral neutron flux. Unfolding codes like SANDP or STAY´SL report integral neutron flux for each energy bin. Hope you can help me with my doubt. Thank you very much.

Best regards

Juan Galicia-Aragon

 

[rpp]

In the nuclear engineering field, I've never seen anybody use the differential neutron flux. I'm not saying there isn't an application, I've just never seen one. Maybe there are some applications in the nuclear physics area?

The flux you calculate in MCNP is usually the integral flux (total flux in a group). I'm not sure exactly what you are trying to do, but you can usually get the integral flux by using a type 4 tally, and then use the "e" multiplier to define different energy bins.

 

[raining Pete]

Hi Juan,

Thank you for sharing your question with us. Calculating the integral neutron flux from MCNP results can be a bit tricky, but I'll try my best to explain it.

To obtain the integral neutron flux, you need to integrate the differential neutron flux over the energy bins. This means taking the neutron flux results for each energy bin and multiplying it by the width of the energy bin. This will give you the contribution of each energy bin to the total neutron flux.

For example, if you have 51 energy bins with widths of 1 MeV each, you would multiply the neutron flux for the first energy bin by 1 MeV, the second energy bin by 2 MeV, and so on until you reach the 51st energy bin, which would be multiplied by 51 MeV. Then, you would add up all of these values to get the total integral neutron flux.

I hope this helps clarify things for you. If you have any further questions, please don't hesitate to ask. Best of luck with your research!