Spallation process is the most important neutron generation method in industry, medicine, etc. This process in the subcritical reactor core is also another technique. In this research, we study the neutronic behavior of the spallation targets consisting of U-238 and Th-232 materials, by MCNPX code. The parameters under study comprise the spallation neutron yield, deposition energy, target geometry; angular spectrum of the neutron output, gas rate and residual mass spectrum. The results show that geometry has the greatest impact on the neutron output spectrum, but not on the residual mass spectrum. Numbers of neutrons per energy unit are stable at higher energies of 1 GeV, then the changes in neutron generation rate are reduced. Furthermore, hydrogen which is the principal factor in swelling of spallation target, consists of about %88 of gas production.

In the present study, zirconium modied aluminide coating on the nickel-base superalloy IN-738LC was rst created by high activity high temperature aluminizing based on the out-of-pack cementation method. Then, Zr coatings were applied to simple aluminide coatings by sputtering and heat treatment in order to study the effect of Zr on the coating microstructure and oxide spallation. Microstructural studies were conducted by using scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), and X-ray diffraction (XRD) microanalysis. The results indicated that zirconium modied aluminide coating, like aluminide coating, has a two-layer structure including a uniform outer layer of NiAl and an interdiffusion layer in which zirconium is in a form of solid solution in the coating. Furthermore, the 300 nm Zr-coated NiAl demonstrated an excellent scale adhesion, a slow oxidation rate and lower amounts of other elements such as Ti and Cr in its oxide layer lead to a pure aluminide oxide layer.

Spallation process is the most significant process for neutron generation in industry and medicine. This process has been used in the subcritical reactor core. In this research, we study the neutronic behavior of non-fissionable and fissionable spallation targets consists of U-238, Th-232, Lead Bismuth Eutectic (LBE) and W-184 materials in cylindrical and conic shapes using MCNPX code. Neutronic parameters consist of spallation neutron yield, deposition energy, and angular spectrum of the neutron output. The gas production rate and residual mass spectrum were investigated. The results of this research indicate that the shape of the target must be selected based on target material and operational purposes. The number of neutrons per energy unit is stable at energies higher than 1 GeV, and the rate of change in neutron generation has been reduced after that. Furthermore, hydrogen is the principal factor in swelling of spallation target and consists of about 88% of gas production. It was found that a target of LBE provides the most favorite parameters for both neutronic and physical properties.

Accelerator-driven systems are extensively developed to generate neutron sources for research, industrial, and medical plans. Different heavy elements are utilized as spallation targets to produce spallation neutrons. Computational methods are efficiently utilized to simulate neutronic behavior of a spallation target. MCNPX 2.6.0 is used as a powerful code based on Monte Carlo stochastic techniques for spallation process computation. This code has the ability to transport different particles using different physical models.In this paper, MCNPX has been utilized to calculate the leaked neutron yield from Pb, lead-bismuth eutectic (LBE), W, Ta, Hg, U, Th, Sn, and Cu cylindrical heavy targets. The effects of the target thickness and diameter on neutron yield value have been investigated via the thickness and diameter variations between 5 to 30 cm and 5 to 20 cm, respectively. Proton-induced radionuclide production into the targets as well as leaked neutron spectra from the targets has been calculated for the targets of an optimum determined dimension. The 1-GeV proton particle has been selected to induce spallation process inside the targets. The 2-mm spatial FWHM distribution has been considered for the 1-mA proton beam.Uranium target produced the highest leaked neutron yield with a 1.32 to 3.7 factor which overweighs the others. A dimension of 15 × 60 cm is suggested for all the cylindrical studied spallation targets. Th target experienced the highest alpha emitter radionuclide production while lighter elements such as Cu and Sn bore the lowest radiotoxicity. LBE liquid spallation target competes with the investigated solid targets in neutronic point of view while has surpass than volatile liquid Hg target.

Accelerator-driven systems are extensively developed to generate neutron sources for research, industrial and medical plans. Different heavy elements are utilized as spallation targets to produce spallation neutrons.Computational methods are efficiently utilized to simulate neutronic behavior of a spallation target. MCNPX 2.6.0 is used as a powerful code based on Monte Carlo stochastic techniques for spallation process computation. This code has the ability to transport different particles using different physical models. In this paper, MCNPX has been utilized to calculate the leaked neutron yield from Pb, LBE, W, Ta, Hg, U, Th, Sn and Cu cylindrical heavy targets. Effects of the target thickness and diameter on neutron yield value have been investigated via the thickness and diameter variations between 5–30 and 5–20 cm, respectively. Proton-induced radionuclide production into the targets as well as leaked neutron spectra from the targets has been calculated for the targets of an optimum determined dimension.1 GeV proton particle has been selected to induce spallation process inside the targets.2 mm spatial FWHM distribution has been considered for the 1 mA proton beam.Uranium target produced the highest leaked neutron yield with a 1.32–3.7 factor overweigh the others. Dimension of 159 60 cm is suggested for all the cylindrical studied spallation targets. Th target experienced the highest alpha emitter radionuclide production while lighter elements such as Cu and Sn bore the lowest radio-toxicity. LBE liquid spallation target competes with the investigated solid targets in neutronic point of view while has surpass than volatile liquid Hg target.

Background: High-energy heavy ions and protons produced by accelerators are used in industrial and medical applications. Recently, Helium (He), Argon (Ar), Krypton (Kr), Carbon (C) and Neon (Ne) heavy ions have been used in the treatment of cancerous tumors. High-energy protons are generally used either directly for the treatment of cancerous tumors or indirectly by neutron production of Lithium (Li), Beryllium (Be) and Thallium (Ta) targets by proton irradiation used for born neutron capture therapy (BNCT) technique. Neutron beams that produced by proton spallation, will activate the brain components before tumors. Methods: In this study, the neutron brain activation has been investigated using Monte Carlo N Particle X Version (MCNPX). Furthermore, in the direct use of high-energy ions for the treatment of cancerous tumors, the production of radioactive elements by heavy ions spallation process in healthy tissues around tumors was calculated by Monte Carlo simulation.Results: Proton beams, neutrons, and heavy ions are used to treat internal tumors. Neutron source spallation of Li, Be, Ta, Lead (Pb) targets that were used in the BNCT therapy process can produce radioactive elements in the brain tissue. The results indicate that the Sodium-22 (22Na) ,24Na, Aluminium-28 (28Al), 29Al, Silicon-32 (32Si), Chlorin-34 metastable(34mCl), Potasium-38 (38K), 40K radioactive elements were produced in brain tissue for BNCT.Conclusion: In this study, the neutron brain activation has been investigated using MCNPX. Furthermore, in the direct use of high-energy ions for the treatment of cancerous tumors, the production of radioactive elements by heavy ions spallation process in healthy tissues around tumors was calculated by Monte Carlo simulation.

Background and Objective: Today, nuclear reactors as a major source of energy in the world, is developing considerably. The main disadvantage of nuclear reactors is producing nuclear waste. This waste is due to the half-life and high environmental impact is radiation poisoning. In this study a new generation of nuclear reactors as ADS introduced where the nuclear waste is used as fuel. Method: Examining ADS nuclear reactors, the concept of ADS and the main components of this type of reactor and how it works are described. Findings: This new generation of nuclear reactors (ADS) has the ability to convert nuclear waste, including meta-uranium elements and fragments of nuclear fission, into low-risk elements with low half-life and low beam toxicity. Its important advantage over other nuclear reactors is that it is safe. Discussion and Conclusions: Given the importance of developing nuclear reactors as a major source of energy production, methods should be used to develop peaceful nuclear technology in the country to maximize its efficiency while minimizing its destructive environmental effects. . The use of a new generation of nuclear reactors (ADS) is one such method.

High-energy heavy ions produced by accelerators are used in industrial and medical applications. Recently carbon ions have been used in the treatment of cancerous tumors. Heavy ions by the spallation process will activate the soft tissue components before tumors. In this research by GEANT4 toolkit and MCNPX code simulation were tried to calculate the secondary particles and radioactive elements produced in the soft tissue around tumors by the carbon ions spallation process. In the MCNPX code, the F8 tally card with the FT8 command was used to extract the activation and spallation information of secondary particles in the Z1=1 to Z2=25 atomic numbers range. It was shown that a wide range of radioactive elements was produced in healthy tissues in carbon therapy. addition to produced secondary particles, the Be-10 and C-14 radioactive elements were produced in high-energy carbon ions in soft tissue. Also, the GEANT4 toolkit result of produced secondary particles dosimetry was shown that the secondary particles dose per carbon ion is between 1.66 to 33.54 nGy for carbon ion energy between 1140 to 5160 MeV. The tail for 3480, 4080, and 5160 MeV of carbon ion energy are 0.12,1.01 and 11 cm respectively. The carbon ion beam divergence increases with beam energy and achieve to 33 mm for 5160 MeV carbon ion.