This study presents the medical radioisotope production performance of a conceptual accelerator driven system (ADS). Lead-bismuth eutectic (LBE) is selected as target material. The subcritical fuel core is conceptually divided into ten equidistant subzones. The ceramic (natural U, Pu)O2fuel mixture and the materials used for radioisotope production (copper, gold, cobalt, holmium, rhenium, thulium, mercury, palladium, thallium, molybdenum, and yttrium) are separately prepared as cylindrical rods cladded with carbon/carbon composite (C/C) and these rods are located in the subzones. In order to obtain the flattened power density, percentages of PuO2in the mixture of UO2and PuO2in the subzones are adjusted in radial direction of the fuel zone. Time-dependent calculations are performed at 1000 MW thermal fission power (Pth) for one hour using the BURN card. The neutronic results show that the investigated ADS has a high neutronic capability, in terms of medical radioisotope productions, spent fuel transmutation and energy multiplication. Moreover, a good quasiuniform power density is achieved in each material case. The peak-to-average fission power density ratio is in the range of 1.02–1.28.

This study presents the neutronic performances of fissile breeding and energy production of a gas cooled accelerator-driven system with LBE-uranium dioxide (UO2) spallation target. The accelerator-driven system is designed and optimized by considering various target materials, in terms of neutronic. Two different materials, LBE + natural UO2 and LBE + 15% enrichment UO2 are selected as target materials. The target zone is divided into two parts, one within the other; the outer part is pure LBE target part, and the inner part is UO2 target part cooled with the helium gas. Tristructural-isotropic (TRISO)-coated fuel particles, containing UO2 fuel, are embedded in a carbon matrix pebble with the packing fraction of a 29%, and the pebbles are placed in the UO2 target part and in the fuel core with the packing fraction of a 60%. The fuel core is cooled with helium that is a high-temperature coolant. The target is bombarded with the continuous beams of a 1 GeV protons to produce high-flux neutrons that enter the fuel core. The fuel core is surrounded with a graphite reflector zone serving as both effective moderation and reflection of these neutrons. Furthermore, the whole system is enclosed by boron carbide, B4C (shielding zone), to prevent the neutrons leakage out of the accelerator-driven system. The highenergy Monte Carlo code MCNPX along with the LA150 library is used for neutronic calculations. The numerical results bring out that the investigated accelerator-driven system has a high neutronic performance, from the energy production and fissile breeding points of view. Namely, it can be obtained over the thermal power of a 350 MW and produced over the fissile breeding of a 300 g/day.

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The Generation Expansion Planning (GEP) problem applies to the expansion of the electricity generation network with new power plant investments. It is a multi-objective optimization problem where the level of uncertainty is very high because of its spatial dimensions and time scale. Therefore, it becomes necessary to introduce in the decision making process a systematic treatment of uncertainty to select the set of nondominated solutions for the Pareto optimal set. In this paper, we will investigate probabilistic Pareto optimality where the probability that one expectedly non-dominated solution dominates another expectedly non-dominated solution in the Pareto optimal set is calculated.

In this study, the medical radioisotope production performance of a conceptual accelerator-driven system is investigated. Lead-bismuth eutectic is used as target material. The fuel core of the considered accelerator-driven system is divided into ten subzones, loaded with uranium carbide and various isotopes (isotopes of copper, gold, cobalt, holmium, rhenium, scandium, and thulium) and cooled with light water. As is known, light water is an effective moderator of neutrons as well as a good coolant. The fuel and the isotopes are separately placed as cylindrical rods with a cladding of carbon composite. The volume fractions of fuel, isotope, cladding and coolant are selected as 25%, 35%, 10% and 30%, respectively. The copper rods are placed into the first five subzones due to the fact that copper isotopes have low capture cross-section. In the case of the each radioisotope production, one of the other considered isotopes that have higher capture cross-section are placed into the following five subzones for optimization of fission, fissile breeding and radioisotope production. The graphite zone is located around the fuel core to reflect the escaping neutrons. Boron carbide (B4C) is used as shielding material. In order to produce more neutrons (about 25-30 neutrons per 1 GeV proton), the target is irradiated with a continuous beam of 1 GeV protons. All neutronic computations have been performed with the high-energy Monte Carlo N-Particle Transport Code using the LA150 data library. The neutronic results obtained from these calculations show that the examined accelerator-driven system has a high neutronic capability, in terms of production of thermal power, fissile fuels, and medical radioisotopes.