Development of a hybrid method to improve the sensitivity and uncertainty analysis for homogenized few-group cross sections. Issue 7 (3rd July 2017)

• Record Type: Journal Article
• Authors: Cao, Liangzhi; Liu, Yong; Shen, Wei; He, Qingming
• Is Part Of: Journal of nuclear science and technology. Volume 54:Issue 7(2017)
• Page Start: 769
• Page End: 783
• Publication Date: 2017-07-03
• Subjects: Nuclear data -- sensitivity and uncertainty -- generalized perturbation theory -- subgroup resonance calculation method; Nuclear engineering -- Periodicals; Nuclear physics -- Periodicals; Nuclear energy -- Periodicals; 621.4805
• DOI: 10.1080/00223131.2017.1315973
• Languages: English
• ISSNs: 0022-3131

Abstract

ABSTRACT: In the framework of two-step method of reactor core calculation, few-group homogenized cross sections generated by lattice-physics calculations are key input parameters for the three-dimensional full-core calculation. Conventional method for few-group cross-sections sensitivity and uncertainty (S&U) analysis related to the nuclear data was performed based on the effective self-shielding cross sections instead of the continuous-energy cross sections, which means resonance self-shielding effect (implicit effect) is neglected. Furthermore, the multi-group covariance data is generated from the continuous-energy cross sections. Therefore, in order to perform S&U analysis with respect to the continuous-energy cross sections for both accuracy and consistency, a hybrid method is proposed in this paper. The subgroup-parameter sensitivity-coefficients are calculated based on the direct perturbation (DP) method. The sensitivity-coefficients of the effective self-shielding cross sections and the responses ( k eff and few-group homogenized cross sections) are calculated based on the generalized perturbation theory (GPT). A boiling water reactor (BWR) pin-cell problem under different power conditions is calculated and analyzed. The numerical results reveal that the proposed hybrid method improves the sensitivity-coefficients of eigenvalue and few-group homogenized cross sections. The temperature effects on the sensitivity-coefficients are demonstrated and the uncertainties are analyzed.