Thermal hydraulic analysis of Syrian MNSR research reactor using RELAP5/Mod3.2 code

This paper presents the development and validation of a MNSR-RELAP5 model. MNSR is a 30 kW, light-water moderated and cooled, beryllium-reflected, tank in pool type research reactor. A RELAP5 model was set up to simulate the entire MNSR system. The model represents all reactor components of primary and secondary loops with the corresponding neutronic and thermal hydraulic characteristics. Under the MNSR operation conditions of natural circulation, normal operation, step reactivity transients and reactivity insertion accidents are simulated. The RELAP5 model was validated by comparing measured and calculated data for the Syrian MNSR reactor. Comparisons include parameters of normal operation at constant power, step reactivity transient and the control rod withdrawal transient. Good agreement was obtained for core coolant inlet and outlet temperatures for operation at constant power, and for development of power level after reactivity insertion, coolant inlet temperature and coolant outlet temperature for the control rod withdrawal transient. As a result of this study, the developed RELAP5 model for Syrian MNSR is shown to be an appropriate model and could be used for other future thermal hydraulic studies.