Study on the linearization workflow for the generation of point-wise cross sections in nuclear data processing

Abstract

In the evaluations, there are various types of nuclear data with different formats, and they should be firstly processed into the libraries with specific formats by the nuclear data processing codes so that the processed libraries can be used by the neutronics codes. In the nuclear data processing, one of the most important procedures is to get the point-wise cross sections (PW XSs) by the linearization. In general, the conventional linearization workflow contains the interval-halving technique and a series of linearization criteria. The precision of the PW XSs and the processing efficiency are controlled by the linearization criteria including the fractional tolerance, the maximum fractional tolerance and the resonance-integral tolerance. The resonance-integral tolerance is used to avoid generating a large number of energy points within the high energy range (HER). It is acceptable for the many applications such as the thermal spectrum reactors. However, for some fast spectrum applications, the PW XSs with higher precision within the HER are important. Therefore, the fractional linearization criterion should be used only (strict criteria) for the conventional linearization workflow to reach the higher precision but the processing efficiency is greatly decreased. To improve the processing efficiency and keep the high precision of PW XSs simultaneously, a new linearization workflow based on the Lagrangian interpolation is proposed and implemented into the nuclear data processing code NECP-Atlas which is developed at Xi’an Jiaotong University. Numerical results show that the precision of PW XSs based on the new linearization workflow agree well with that based on the conventional linearization workflow with strict criteria and the processing efficiency is significantly improved.