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Article Citation - WoS: 6Assessment of Criticality and Burn Up Behavior of Candu Reactors With Nuclear Waste Trans Uranium Fuel(Pergamon-elsevier Science Ltd, 2012) Sahin, Sumer; Ahmed, Rizwan; Khan, Mohammad JavedLarge quantities of nuclear waste plutonium and minor actinides (MAs) have been accumulated in the civilian light water reactors (LWRs) and CANDU reactors. These trans uranium (TRU) elements are all fissionable, and thus can be considered as fissile fuel materials in form of mixed fuel with thorium or naturanium in the latter. CANDU fuel compacts made of tristructural-isotropic (TRISO) type pellets would withstand very high burn ups without fuel change. As carbide fuels allow higher fissile material density than oxide fuels, following fuel compositions have been selected for investigations: (1) 90% nat-UC + 10% TRUC, (2) 70% nat-UC + 30% TRUC and (3) 50% nat-UC + 50% TRUC. Higher TRUC charge leads to longer power plant operation periods without fuel change. The behavior of the criticality k(infinity) and the burn up values of the reactor have been pursued by full power operation for > similar to 12 years. For these selected fuel compositions, the reactor criticality starts by k(infinity) = 1.4443, 1.4872 and 1.5238, where corresponding reactor operation times and burn up values have been calculated as 2.8 years, 8 years and 12.5 years, and 62, 430 MW.D/MT, 176,000 and 280,000 MW.D/MT, with fuel consumption rates of similar to 16, 5.68 and 3.57 g/MW.D respectively. These high burn ups would reduce the nuclear waste mass per unit energy output drastically. The study has show clearly that TRU in form of TRISO fuel pellets will provide sufficient criticality as well as reasonable burn up for CANDU reactors in order to justify their consideration as alternative fuel. (c) 2012 Elsevier Ltd. All rights reserved.Article Citation - WoS: 13Citation - Scopus: 14Commercial Utilization of Weapon Grade Plutonium as Triso Fuel in Conventional Candu Reactors(Pergamon-elsevier Science Ltd, 2012) Sahin, Sumer; Sahin, Haci Mehmet; Acir, AdemLarge quantities of weapon grade (WG) plutonium have been accumulated in the nuclear warheads. Plutonium and heavy water moderator can give a good combination with respect to neutron economy. TRISO type fuel can withstand very high fuel burn up levels. The paper investigates the prospects of utilization of TRISO fuel made of WG-plutonium in CANDU reactors. Three different fuel compositions have been investigated: (1): 90% ThC + 10% PuC, (2): 70% ThC + 30% PuC and (3): 50% ThC + 50% PuC. The temporal variation of the criticality k(infinity) and the burn-up values of the reactor have been calculated by full power operation up to 17 years. Calculated startup criticalities for these fuel modes are k(infinity.0)= 1.6403, 1.7228 and 1.7662, respectively. Attainable burn up values and reactor operation times without new fuel charge will be 94700, 265000 and 425000 MW.D/MT and along with continuous operation periods of similar to 3.5, 10 and 17 years, respectively, for the corresponding modes. These high burn ups would reduce fuel fabrication costs and nuclear waste mass for final disposal per unit energy drastically. (C) 2012 Elsevier Ltd. All rights reserved.
