Browsing by Author "Sahin, S."

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Citation - WoS: 3
Candu Reactors With Reactor Grade Plutonium/Thorium Carbide Fuel
(Carl Hanser verlag, 2011) Sahin, S.; Khan, M. J.; Ahmed, R.; 01. Atılım University
Reactor grade (RG) plutonium, accumulated as nuclear waste of commercial reactors can be re-utilized in CANDU reactors. TRISO type fuel can withstand very high fuel burn ups. On the other hand, carbide fuel would have higher neutronic and thermal performance than oxide fuel. In the present work, RG-PuC/ThC TRISO fuels particles are imbedded body-centered cubic (BCC) in a graphite matrix with a volume fraction of 60%. The fuel compacts conform to the dimensions of sintered CANDU fuel compacts are inserted in 37 zircolay rods to build the fuel zone of a bundle. Investigations have been conducted on a conventional CANDU reactor based on GENTILLYII design with 380 fuel bundles in the core. Three mixed fuel composition have been selected for numerical calculation; (1) 10% RG-PuC + 90% ThC; (2) 30% RG-PuC + 70% ThC; (3) 50% RG-PuC + 50% ThC. Initial reactor criticality values for the modes (I), (2) and (3) are calculated as k(infinity,0) = 1.4848, 1.5756 and 1.627, respectively. Corresponding operation lifetimes are similar to 2.7, 8.4, and 15 years and with burn ups of similar to 72000, 222 000 and 366 000 MW.d/tonne, respectively Higher initial plutonium charge leads to higher burn ups and longer operation periods. In the course of reactor operation, most of the plutonium will be incinerated. At the end of life, remnants of plutonium isotopes would survive; and few amounts of uranium, americium and curium isotopes would be produced.
Citation - WoS: 6
Performance Analysis of ²³³u for Fixed Bed Nuclear Reactors
(Carl Hanser verlag, 2010) Sahin, S.; Acir, A.; Sahin, H. M.; 01. Atılım University
Criticality and burn up behavior of the Fixed Bed Nuclear Reactor (FBNR) are investigated for the mixed fuel (UO2)-U-233/ThO2 as an alternative to low enriched (UO2)-U-235 fuel. CERMET fuel with a zirconium matrix and cladding has been used throughout the study. The main results of the study can be summarized as follows: Reactor criticality is already achieved by similar to 2% (UO2)-U-233 with the mixed (UO2)-U-233/ThO2 fuel. At higher U-233 fractions, reactor criticality rises rapidly and exceeds k(eff)>1.5 already by 9% (UO2)-U-233. With 100% (UO2)-U-233, start up criticality can reach k(eff)=2.0975. Time dependent reactor criticality k(eff) and fuel burn up have been investigated for two different mixed fuel (UO2)-U-233/ThO2 compositions, namely: 4% (UO2)-U-233 + 96% ThO2 for a reactor power of 40 MWel (120 MWth) and 9% (UO2)-U-233 + 91% ThO2 for a reactor power of 70 MWel (210 MWth). Sufficient reactor criticality (k(eff) > 1.06) for continuous operation without fuel change can he sustained during similar to 5 and 12 years with 4% and 9% (UO2)-U-233 fractions in the mixed fuel, leading to burn ups of similar to 36000 and >105000 MWD/t, respectively. Thorium based fuel produces no prolific uranium. Plutonium production remains negligible.