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Article Citation - WoS: 6Performance Analysis of 233u for Fixed Bed Nuclear Reactors(Carl Hanser verlag, 2010) Sahin, S.; Acir, A.; Sahin, H. M.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.Article Citation - WoS: 3Candu Reactors With Reactor Grade Plutonium/Thorium Carbide Fuel(Carl Hanser verlag, 2011) Sahin, S.; Khan, M. J.; Ahmed, R.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.Article Preparation of Human Resources for Future Nuclear Energy Using Fbnr as the Instrument of Learning(Carl Hanser verlag, 2015) Sefidvash, Farhang; Espinoza, Patricio; Aguilera, Maribel Luna; Ayala, Edy; Guerrero, Victor Hugo; Santos, Roque; Kanoute, MamadouAn increasing number of developing countries are showing interest to become the emerging countries to nuclear energy. Most of these countries lack human resources and adequate infrastructures to enter such a venture. The principle objective of activities of FBNR Group is to train human resources for the countries that at the present lack the necessary conditions, but aim at the future clean and safe nuclear energy through the fourth generation and INPRO compatible nuclear reactors. The preparation for the future nuclear energy is done through development of innovative nuclear reactor that meets the INPRO philosophies and criteria. These countries may or may not have decided as yet to utilize nuclear energy, but are interested to gain a strong educational foundation for their future. The research and development of a small innovative nuclear reactor FBNR is used as the instrument for learning. The young scientists will learn how to be innovative with the vision of INPRO philosophy and criteria.Article Citation - WoS: 6Citation - Scopus: 6Effect of Martensite Volume Fraction on Mechanical Properties of Dual-Phase Treated Aisi-4012 Sheet Steels(Carl Hanser verlag, 2010) Aksakal, B.; Karaca, F.; Arikan, R.Hot rolled AISI-4012 sheet steels have been heat treated to obtain a ductile dual phase microstructure. The specimens were heat treated in the ferrite (a) and austenite (7) phase region at temperatures of 740, 760, 790 and 820 degrees C and corresponding time intervals of 15, 30, 60 and 90 min and then quenched into water. Hardness measurements, tensile, bending, and impact tests were performed in order to determine the mechanical properties of the dual phase steel. These were examined with respect to the martensite volume fraction. Both the flow and tensile stresses increased whereas elongation decreased with increasing dual phase treatment temperature and martensite volume fraction. The optimum mechanical properties and the appropriate dual-phase microstructure are achieved at 740 and 760 degrees C annealing with subsequent water quenching. From examinations it was deduced that ductile fracture occurred in the tested samples.
