VARIATION OF TOTAL EMISSIVITY OF FUEL PIN OF IPHWR WITH TEMPERATURE
In Nuclear reactor heat is generated internally due to fission chain reaction. Coolant system is used to take away this heat in order to produce useful electrical power. Under conditions of large break loss of coolant accident (LOCA) coincident with the failure of emergency core cooling system (ECCS) coolant channel would be voided leading to rapid temperature rise of fuel pins and pressure tube. At high temperature, radiation mode of heat transfer becomes very predominant in the coolant channel and heat is dissipated to the moderator through calandria tube (CT). Emissivity of fuel clad which is made of Zircaloy-4, is an important parameter for estimating the radiation heat transfer between fuel bundle and pressure tube (PT). Experiments have been conducted to evaluate the variation of total emissivity of pre-oxidized clad (autoclaved) fuel pin of 220MWe Indian pressurized heavy water reactor (IPHWR) with temperature under inert atmosphere. From experimental analysis it has been found that the emissivity of the fuel pin decreases with corresponding rise in temperature.