Neutron Cross-Section Uncertainty and Reactivity Analysis in MOX and Metal Fuels for Sodium-Cooled Fast Reactor

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Dear authors,

The paper that you present is very basic in its analysis. You claim to deal with the Doppler constant but never go beyond the calculation of the sensitivity of that constant to nuclear data. The paper needs a lot of work to be improved. 

1. Sensitivity coefficients of the Doppler constant. You can check Eq 6 in the following publication - https://www.sciencedirect.com/science/article/pii/S0149197016302773
2. What are the uncertainties? Knowledge of the sensitivity coefficient is nice, but what we need to know is the uncertainty of Doppler and k-eff as a result of uncertainties in nuclear data. By using ENDF-B/VII.1 you can use the covariances available in this library and perturb the data, as stated in Eq 3 in the article mentioned above. 

Without those two, it is hard to justify your article as it is very basic, and there are numerous similar articles online. 

A few additional comments are in the attached file

Comments for author File: Comments.pdf

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The author addresses the question of the impact of various cross-section uncertainties on the expected neutron yield from a next-generation sodium-cooled fast reactor.  The study looks at the impact of the current uncertainties in neutron capture cross-sections, thermal broadening, and metal fuel configurations on the neutron multiplication factor (keff).

The paper is very clear in its methodology and is well-written.  It makes use of the Serpent built-in sensitivity module to estimate the impact on keff from the variety of uncertainties mentioned above.  In many cases, these uncertainties are sufficiently large to warrant a more comprehensive study.  

I highlight a few items to consider:

• The thermal broadening study is limited to two "temperature" scenarios, which assumes a linear dependence of keff on the Doppler shift.  It would be better to have samled a range of temperatures to see any potential non-linear trends in the modeling.
• Is Serpent built-in sensitivity module a simple shift of one uncertainty at a time at its maximal uncertainty, or a Monte-Carlo based method?  Can this be elaborated?
  
  
• No cross-correlations are presented.  Are they expected to occur?

Given the scope of the paper, the items mentioned above do not need to be addressed but should strongly be featured in any future, more comprehensive study.

Publication is recommended.

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf