Development and Verification of Covariance Data Generation Module in NECP-Atlas

[Results]: A comparative verification is carried out with the covariance data production module in the nuclear data processing software NJOY21 to demonstrate the accuracy of the multi-group covariance databases produced by NECP-Atlas and the maximum bias is less than 0.1%. Utilizing Monte Carlo calculation code NECP-MCX and uncertainty analysis code NECP-UNICORN, sensitivity coefficients for different benchmarks are calculated.

By incorporating both continuous energy covariance databases and multi-group covariance data, and utilizing the "Sandwich formula," the final uncertainties are computed. The results indicate that the uncertainties calculated using the multi-group covariance data generated by NECP-Atlas exhibit comparable accuracy to those obtained with NJOY21. [Conclusions]: The precision in creating both continuous energy covariance and multi-group covariance meets the requirements for usage in Monte Carlo programs and deterministic programs, validating the efficacy of covar_calc module within NECP-Atlas for uncertainty quantification in reactor physics analysis.