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India’s newest nuclear reactor connects to grid
Unit 4 at Kakrapar nuclear power plant was connected to the grid on February 20, the Nuclear Power Corporation of India Ltd. (NPCIL) has announced. The 700-MWe pressurized heavy water reactor achieved first criticality on December 17, 2023.
Alexander R. Clark, John Mattingly, Jeffrey A. Favorite
Nuclear Science and Engineering | Volume 194 | Number 4 | April 2020 | Pages 308-333
Technical Paper | doi.org/10.1080/00295639.2019.1698267
Articles are hosted by Taylor and Francis Online.
This paper presents the first application of model calibration to neutron multiplicity counting (NMC) experiments for cross-section optimization that is informed by adjoint-based sensitivity analysis (SA) and first-order uncertainty quantification (UQ). We summarize previous work on SA applied to NMC and describe notable modifications and additions. We give the procedure for first-order UQ and Bayesian-inference-based parameter estimation (PE). We then discuss model calibration applied to NMC of a 4.5-kg sphere of weapons-grade, alpha-phase plutonium metal (the BeRP ball) with the nPod neutron multiplicity counter. For the BeRP ball in bare and polyethylene-reflected configurations, we discuss the sensitivity of the first- and second-moment detector responses (i.e., first and second moments of the NMC distribution, respectively) to the cross sections. We describe the sources of uncertainty in the measured and simulated responses. Specifically, uncertainty in the measured responses is due to both random and systematic sources. Uncertainty in the simulated responses is due to the cross-section covariances. We describe in detail the adjustment to the cross sections and cross-section covariances due to the optimization. Due to the contribution of systematic uncertainties to the measured response uncertainties, the adjustment to the cross sections is similar in trend but larger in magnitude compared to that recommended by previous work. We compare the measured responses to responses simulated with nominal and optimized cross sections, demonstrating that the best-estimate cross sections produce simulations of NMC experiments that are more accurate with reduced uncertainty.