A major problem encountered in the designing and construction of any nuclear reactor system is the removal of heat from the core of the reactor. In the V.P.I. UTR-10, the heat is removed from the fuel plates by the light water moderator-coolant which is pumped between the plates. The maximum temperature which the fuel will attain is determined by the coolant temperature, the coolant flow rate, and the reactor operating power. The latter two of these are given by the reactor instrumentation. No provisions were made which allowed the temperature of the coolant in the region of the fuel elements to be measured. In order to ascertain this coolant temperature, an array of copper-constantan thermocouples was inserted between the individual plates of the fuel elements. The temperature of the coolant near the bottom and top of the 144 fuel plates was found using this thermocouple arrangement. These results were used to predict temperature of the coolant and fuel at a power level of 100 Kw. It is believed that with appropriate modifications of the present system no major difficulties should be encountered in increasing the reactor's licensed power from 10 Kw to 100 Kw. / Master of Science