Real Variance Estimation Using an Intercycle Fission Source Correlation for Monte Carlo Eigenvalue Calculations

McCard: Monte Carlo Code for Advanced Reactor Design and Analysis

“…McCARD provides four methods available currently to estimate the real variance of a tallied parameter: the Gelbard's batch method [17], the Ueki's method [18], the FSD's inter-cycle correlation method [19], and the history-based batch method [20]. The Gelbard's batch method estimates the real variance by splitting the whole active cycles into non-overlapping batches, averaging cycle-wise tally estimates over each batch, and estimating the sample variance from the batch-averages.…”

“…There are several studies on how to estimate the biases of the sample variances to determine the real variances of the tallied parameters. McCARD offers four different methods currently available to estimate the biases of the sample variances or the real variances; the Gelbard's batch method [17], the Ueki's method [18], the FSD's intercycle correlation method [19], and the history-based batch method [20]. · In addition to the static neutronics design parameter calculation module, McCARD has the kinetics parameter calculation module designed to calculate the adjoint-weighted kinetics parameters such as the effective delayed neutron fraction, βeff, and the prompt neutron generation time, Λ.…”

Standard Deviation of Local Tallies in Global Monte Carlo Calculation of Nuclear Reactor Core

“…4,6,11,12) Each of these works has its own formalism; however, all of them arrived at the formula below: e e ðmþ1Þ ¼ A 0ẽ e ðmÞ þ" " ðmþ1Þ ;…”

“…Equation (5) immediately follows from the definition ofẽ e ðmÞ and" " ðmÞ . Equation (6) can be derived with no assumption. 14) Therefore, Eqs.…”

“…(3), (5), and (6). This work was rediscovered and successfully applied to dominance ratio computation 4) and the confidence interval estimation of keffective eigenvalue.…”