Abstract
Neutronics calculation for nuclear reactor with high-fidelity technology can significantly reduce the uncertainties propagated from numerical approximation error and model error. However, the uncertainty of input parameters inevitably exists, especially for nuclear data. On the other hand, resonance self-shielding calculation is essential for multi-group assumption based high-fidelity neutronics calculation, which introduce the implicit effect for calculation responses. In order to fully consider the implicit effects in the process of uncertainty quantification, a generalized perturbation theory (GPT) based implicit sensitivity calculation method is proposed in this paper. Combining the explicit sensitivity coefficient, which can be quantified using classic perturbation theory, the total sensitivity coefficient of calculation responses is obtained. Then the total sensitivity and uncertainty module is established in self-developed neutron transport code with high-fidelity technology-HNET. To verify the accuracy of the sensitivity calculation methods proposed in this paper, a two-dimensional fuel pin problem is chosen to verify the sensitivity results, and the numerical results show good agreement with results calculated by a direct perturbation method. Finally, uncertainty analysis for two-dimensional fuel pin problem is performed and some general conclusions are obtained from the numerical results.
Highlights
With the rapid development of high-performance computing power, high-fidelity calculation method has gradually become an essential method to depict neutron physical phenomena, and the calculation results affects the design, construction, and even the economic and safety aspects of the nuclear reactor
The results indicated that for light water reactor (LWR) problems, the implicit part cause significant effect, and the total sensitivity and analysis scheme should be established for LWR to provide convincing sensitivity and uncertainty analysis results for the calculated responses with respect to the multi-group microscopic cross sections
According to the linear relationship test, 2% relative perturbation factor is in the region with strongest linear relationship, so a 2% relative perturbation of multigroup cross sections is used in the direct perturbation (DP) method for sensitivity verification
Summary
With the rapid development of high-performance computing power, high-fidelity calculation method has gradually become an essential method to depict neutron physical phenomena, and the calculation results affects the design, construction, and even the economic and safety aspects of the nuclear reactor. Uncertainties inevitably exist in the process of high-fidelity neutron physics calculations. There are three basic uncertainty sources, including modeling error, numerical solution error and input parameter uncertainties The first two uncertainty sources can be effectively decreased by using well-established high-fidelity numerical method for neutronics calculation, but the uncertainty of the multi-group cross sections is still significant The traditional conservative assumptions and large safety margins do not meet research requirements and Best-Estimation Plus Uncertainty (BEPU), which is proposed by IAEA, has become the mainstream scheme for safety
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
