Temperature distribution in nuclear fuel rod and variation of the neutronic performance parameters are investigated for different coolants under various first wall loads (P-w = 2, 5, 7, 8, 9 and 10 MW m(-2)) in (D, T) (deuterium and tritium) driven and fueled with UO2 hybrid reactors. Plasma chamber dimension, DR, with a line fusion neutron source is 300 cm. The fissile fuel zone is considered to be cooled with four different coolants with various volume fractions, the volumetric ratio of coolant-to-fuel [epsilon (Vm/V-f) = 1:2, 1:1, and 2:1], gas (He, CO2), flibe (Li2BeF4). natural lithium (Li). and eutectic lithium (Li17Pb8.3). Calculation in the fuel rods and the behavior of the fissile fuel have been observed during 4 years for discrete time intervals of Deltat = 15 days and by a plant factor (PF) of 75%. As a result of the calculation, cumulative fissile fuel enrichment (CFFE) value indicating rejuvenation performance has increased by increasing P-w for all coolants and epsilon. Although CFFE and neutronic performance parameter values increase to the higher values by increasing P-w, the maximum temperature in the centerline of the fuel roads has exceeded the melting point (T-m > 2830 degreesC) of the fuel material during the operation periods. However, the best CFFE (11.154%) is obtained in gas coolant blanket for epsilon = 1:2 (29.462% coolant, 58.924% fuel, 11.614% clad), under 10 MW m(-2) first wall load, followed by flibe with CFFE = 11.081% for epsilon = 2:1 (62.557% coolant, 31.278% fuel, 6.165% clad), under 7 MW m(-2), and flibe with CFFE = 9.995% for, epsilon = 1:1 (45.515% coolant, 45.515% fuel, 8.971% clad), under 7 MW m(-2) during operation period without obtained in fuel rod row#10 in gas, natural lithium. and eutectic lithium coolant blankets, it has been obtained in fuel rod row#1 in flibe coolant blanket for all epsilon and P-w. At the same condition. the best neutronic performance parameter values, tritium breeding ratio (TBR) = 1.4454, energy multiplication factor (M) = 9.2018, and neutron leakage (L) = 0.0872, have been obtained in eutectic lithium coolant blankets for the epsilon = 1:2, followed by gas, natural lithium, and flibe coolant blankets. The isotopic percentage of Pu-240 is higher than 5% in all blankets for P-w greater than or equal to 7 MW m(-2), so that plutonium component in all blankets can be never reach a nuclear weapon grade quality during the operation period. (C) 2001 Elsevier Science Ltd. All rights reserved.