Sensitivity calculations
Serpent relies on the collision history based first order GPT equivalent implementation[1] to calculate sensitivities of various responses to various perturbations. As a simple example, the sensitivity of the effective multiplication factor to the different nuclear cross sections can be calculated.
Contents
Implementation
Input
Adding a response
set sensresp NAME FLAG
Where the different response names and flags are as follows
| NAME | explanation of NAME | FLAG | explanation of FLAG |
| keff | sensitivity of effective multiplication factor to perturbation | 0/1 | OFF/ON |
| beff | sensitivity of effective delayed neutron fraction to perturbation | 0/1 | OFF/ON |
| leff | sensitivity of effective prompt generation time to perturbation | 0/1 | OFF/ON |
Adding a perturbation
set senspert NAME FLAG
Where the different perturbation names and flags are as follows
| NAME | explanation of NAME | FLAG | explanation of FLAG |
| xs | perturbation of basic cross sections | 0/1 | OFF/ON |
| chi | perturbation of fission spectrum | 0/1 | OFF/ON |
| nubar | perturbation of fission nubar | 0/1 | OFF/ON |
| eleg | perturbation of Legendre moments of elastic scattering angular distribution |
0/1/2/3/4/5/6/7 | Number of Legendre moments to perturb. |
Choosing nuclides to perturb
The perturbed nuclides can be specified by giving a list of the ZAI-numbers to include
set senspert zailist ZAI1 ZAI2 ...
for example
set senspert zailist 922350 922380
for perturbations affecting 235U and 238U. By giving the control words total and/or sum in the list of ZAI-numbers, the total sensitivity over all ZAIs present in the calculation and the sum sensitivity of the listed ZAIs will be calculated, respectively. All nuclides present in the calculation can be included with
set senspert zailist all
Choosing materials to perturb
The materials, where the perturbations are applied can similarly be specified by giving a list of the material names
set senspert matlist MAT1 MAT2 ...
for example
set senspert matlist fuel coolant
for perturbations affecting interactions in materials fuel and coolant. By giving the control words total and/or sum in the list of material names, the total sensitivity over all materials present in the calculation and the sum sensitivity of the listed materials will be calculated, respectively.
All materials present in the calculation can be included with
set senspert matlist all
this will automatically include the calculation of the total sensitivity.
Additional options
Number of latent generations.
IFP chain length.
Response based tallying or event based tallying.
Event bank.
Output
Examples
References
- ^ Aufiero, M. et al. "A collision history-based approach to sensitivity/perturbation calculations in the continuous energy Monte Carlo code SERPENT", Ann. Nucl. Energy, 152 (2015) 245-258. DOI:10.1016/j.anucene.2015.05.008
