Derivation of the source term, dose results and associated radiological consequences for the Greek Research Reactor – 1

•Source term derivation of postulated accident sequences in a research reactor.•Various containment ventilation scenarios considered for source term calculations.•Source term parametric analysis performed in case of lack of ventilation.•JRODOS employed for dose calculations under eighteen modeled scenarios.•Estimation of radiological consequences during typical & adverse weather scenarios. The estimated source term, dose results and radiological consequences of selected accident sequences in the Greek Research Reactor – 1 are presented and discussed. A systematic approach has been adopted to perform the necessary calculations in accordance with the latest computational developments and IAEA recommendations. Loss-of-coolant, reactivity insertion and fuel channel blockage accident sequences have been selected to derive the associated source terms under three distinct containment ventilation scenarios. Core damage has been conservatively assessed for each accident sequence while the ventilation has been assumed to function within the efficiency limits defined at the Safety Analysis Report. In case of lack of ventilation a parametric analysis is also performed to examine the dependency of the source term on the containment leakage rate. A typical as well as an adverse meteorological scenario have been defined in the JRODOS computational platform in order to predict the effective, lung and thyroid doses within a region defined by a 15km radius downwind from the reactor building. The radiological consequences of the eighteen scenarios associated with the accident sequences are presented and discussed.