Optimisation of the control curves of load-changing nuclear power units taking into account thermal stress
DOI:
https://doi.org/10.24425/ather.2025.156835Abstract
Besides the increasing share of uncontrollable renewables in the energy mix, the consumption/production balance of the grid must be permanently assured. Additionally, the successive stopping of traditional, fossil-fuelled power plants necessitates the controllability also of nuclear power plants. The major drawback of the load-following operation of such units is the side effect of load changes. They are, namely, carried out via non-stationary transitions, during which the temperature changes result in thermal stresses. The most critical, practically unchangeable part of the plant is the reactor pressure vessel, which is a thick-walled component of complex geometry. Hence, determining the optimal curves of the unit’s available control inputs is a crucial issue. For this, several tools are needed, such as a dynamical model of the entire power unit, a dynamical description of the thermal stress in the most critical points, a practical system of criteria of the optimisation condition, and numerical method for seeking the optimal pathway. The results demonstrate that optimised actuator trajectories can reduce thermally induced stress in the nozzle corner of the reactor pressure vessel during load-following operation.References
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