Core temperature and containment pressure have been calculated, for LEU core of PARR-1, following a large break Loss of Coolant Accident (LOCA). Heat transfer from bare reactor core to containment air has been calculated using analytical methods. The analysis shows that the core would start melting 6 minutes from its complete uncovery if emergency core cooling system fails to operate. If the emergency exhaust system also fails simultaneously and normal leakage through the building penetrations is considered, the pressure inside the containment would reach a peak value of 0.26 psig (18 cm of water column) about 1.5 hrs from start of the accident. The containment would remain pressurized for about 10 hrs and activity would be released to atmosphere during this period. (author).