Journal of Energy - Energija

Hybrid Shielding Calculations of GBC32 Cask

2026-01-14T14:34:12+01:00

This paper presents an evaluation of the shielding performance of the Generic Burnup Credit Cask (GBC-32) containing 32 Westinghouse 17x17 spent fuel assemblies. The spent fuel source term characterization was done in previous work, for which burnup/depletion calculations of TRITON-NEWT in tandem with ORIGEN-S were performed, generating collapsed cross section libraries as a function of fuel enrichment and burnup level. The hybrid shielding methodology of MAVRIC sequence in SCALE6.1.3 code was used to quantify neutron-gamma radiation field and dose rates around the cask, taking previously prepared source terms with ORIGEN-ARP module. For that purpose, to expedite the input preparation, a special routine in C-language was programmed to read ORIGEN-ARP multigroup output data and provide normalized neutron-gamma (n-g) spectra with the associated intensities (particles/s/MTU). This distributed multisource in Monte Carlo cask model included spent fuel neutrons and photons, photons from (n,g) reactions and photons from activated upper/lower hardware regions of spent fuel assemblies. Different fuel loading patterns were investigated, ranging from generic (one zone) to more realistic one (three zones) using averaged values of burnup, fuel enrichment and cooling time period. The FW-CADIS variance reduction technique was successfully applied for achieving global neutron-gamma flux convergence in radial and axial directions of the cask. The presented MC dosimetry results correspond to normal cask conditions, but an accidental scenario was also investigated, for which the resin neutron shield was removed from the shielding configuration.

Natural Heat Transfer Performance of Helium Filled Spent Fuel Multi Purpose Container Calculated for Different Initial Pressures

2026-01-14T14:36:37+01:00

The simple model of helium filled Holtec’s Multi Purpose Container (MPC) for 37 spent fuel assemblies was developed and the calculation was performed using the Ansys Fluent code in steady state. The flow and temperature distribution within the MPC was calculated for different initial helium pressures, and for limiting cask heat loading found in the NPP Krsko SFDS (Spent Fuel Dry Storage) campaign number 1. The determined relationship between helium top to bottom temperature increase and helium pressure decrease can be used as a measure of cask leakage. In addition, lateral temperature distribution in the top MPC plenum, influenced partially by different spent fuel assembly loading, should be checked as a cause for temperature variation at the MPC external top surface, where RTD (Resistance Temperature Detector) detectors are installed.

Development and Validation of Dynamic RMS Models for Power System Analysis

2026-02-06T10:41:26+01:00

The increasing integration of converter-based renewable
energy sources is reducing the inertia of power systems
and amplifying transient oscillations following disturbances. As a
result, the accuracy of dynamic simulation models of generating
units has become essential for reliable assessment of system
transient stability. This paper presents a validation procedure
for an root-mean-square dynamic model of Unit D of the
Zakuˇcac hydropower plant, based on measurements obtained
from a phasor measurement unit during and after a real system
disturbance. The validation process includes preparation of measurement
data, alignment of the static model with steady-state
measurements, and detailed tuning of dynamic model parameters.
The achieved results demonstrate a high level of agreement
between simulated and measured responses. In addition, the
paper highlights the importance of standardizing requirements
for the submission of simulation models, as accurate modeling of
individual generating facilities directly enhances the credibility
of system-level analyses and supports secure and stable power
system operation under increasing system complexity.

Smart Hybrid Metaheuristic Model for Enhanced Wind Energy Production

2026-02-06T11:00:33+01:00

This study presents a hybrid Particle Swarm Optimization–Genetic Algorithm (PSO-GA) technology integrated into a structured three-phase strategy to address the wind farm layout optimization (WFLO) problem. In order to enhance total energy efficiency through intelligent turbine location, the proposed strategy is applied to a particular wind farm scenario. Three case studies, each representing varying degrees of wake and non-wake settings, are analyzed to assess the robustness of this method. In order to prevent severe wake interference, the system finds the best location for turbines while strictly following to industry-standard spacing standards. The suggested hybrid model consistently improves energy extraction and reduces wake losses by 20–28% in all scenarios when compared to current method like PSO-based design by [21]. The hybrid PSO-GA still has a moderate computational cost, taking about twenty seconds each simulation. This is just 10–15% more than standalone PSO, but it produces far greater convergence stability.