Uncertainty quantification of PWR spent fuel due to nuclear data and modeling parameters

• Main Authors: Bamidele Ebiwonjumi, Chidong Kong, Peng Zhang, Alexey Cherezov, Deokjung Lee
• Format: Article
• Language: English
• Published: Elsevier 2021-03-01
• Series: Nuclear Engineering and Technology
• Subjects: STREAM; Spent nuclear fuel; PWR; Uncertainty quantification; Stochastic sampling; Surrogate models
• Online Access: http://www.sciencedirect.com/science/article/pii/S1738573320303521

Uncertainties are calculated for pressurized water reactor (PWR) spent nuclear fuel (SNF) characteristics. The deterministic code STREAM is currently being used as an SNF analysis tool to obtain isotopic inventory, radioactivity, decay heat, neutron and gamma source strengths. The SNF analysis capability of STREAM was recently validated. However, the uncertainty analysis is yet to be conducted. To estimate the uncertainty due to nuclear data, STREAM is used to perturb nuclear cross section (XS) and resonance integral (RI) libraries produced by NJOY99. The perturbation of XS and RI involves the stochastic sampling of ENDF/B-VII.1 covariance data. To estimate the uncertainty due to modeling parameters (fuel design and irradiation history), surrogate models are built based on polynomial chaos expansion (PCE) and variance-based sensitivity indices (i.e., Sobol’ indices) are employed to perform global sensitivity analysis (GSA). The calculation results indicate that uncertainty of SNF due to modeling parameters are also very important and as a result can contribute significantly to the difference of uncertainties due to nuclear data and modeling parameters. In addition, the surrogate model offers a computationally efficient approach with significantly reduced computation time, to accurately evaluate uncertainties of SNF integral characteristics.