MELGYM: A dynamic control interface for MELCOR simulations

MELCOR is a computer code for the simulation and safety analysis of nuclear facilities, comprising several modules for the calculation of thermal–hydraulic phenomena and aerosol physics. However, MELCOR offers limited support for interactive control, such as valve opening or flow rates redefinition, as its batch execution mode does not allow real-time modification of model parameters. To overcome this limitation, we present MELGYM, a Gymnasium-based interface that facilitates interactive control in MELCOR. MELGYM enables the training of reinforcement learning agents on MELCOR simulations, introducing real-time interaction and enabling the definition of reward functions based on simulation outcomes.