An analytical solution for thermal–hydraulic analysis and safety margins in MTR-type research reactors cooled by natural convection

An analytical solution has been developed to analyze the thermal–hydraulic behavior of MTR research reactors under steady-state natural convection. The approach is based on the one-dimensional conservation equations of mass, energy, momentum, and Boussinesq approximation as the equation of state. SILOE Research Reactor and Tehran Research Reactor (TRR) are taken as the benchmark problems. For all ranges of power under single phase natural convection, the relative difference between analytical predictions and experimental measurements lies in the range 0.01–7.0%. Also, the results are compared with the corresponding results obtained with CONVEC V 3.40 computer code. Having achieved a good agreement shows the analytical solution is practicable to predict safety margins for MTR-type research reactors under natural convection. The safe operating power levels for TRR and the safety margins against onset of nucleate boiling, pulsed boiling, and burnout are evaluated with this analytical solution.

► An analytical solution is developed for natural convection in the MTR reactors.
► The approach has been validated with the experimental and CONVEC V 3.40 results.
► Safe operating power level and safety margins for TRR have been evaluated.