Independent fission yields of 235U induced by thermal neutrons as well as their covariance updated by the generalized least squares method

The generalized least squares (GLS) updating approach was adopted to evaluate the fission yield covariances with the constraints from basic physical conservation equation and chain yield data, using the nuclear data files from ENDF/B-VIII.0, JENDL-5 and JEFF-3.3. Based on these updated data, summation calculation was performed for fission pulse decay heat of thermal neutron-induced fission of 235U. The uncertainties of decay heat were obtained through generalized perturbation theory, including the uncertainties propagated from fission yield, decay energy, decay constant and branching ratio.