Calculation of the Neutron Parameters for Accelerator-Driven Subcritical Reactors

In this paper, the accelerator-driven subcritical reactor (ADSR) is simulated based on structure of the TRIGA-Mark II reactor. A proton beam is accelerated and interacts on the lead target. Two cases of using lead are considered here: firstly, solid lead is referred to as spallation neutron target and water as the coolant; secondly, molten lead is considered both as a target and as a coolant. The proton beam in the energy range from 115 MeV to 2000 MeV interacts with the lead to create neutrons. The neutron parameters as neutron yield Yn/p, neutron multiplication factor k, the radial and axial distributions of the neutron flux in the core have been calculated by using MCNPX program. The results show that the neutron yield increases as the energies of the proton beam increases. When using the lead target, the differences between the neutron yield are from 4.2% to 14.2% depending on the energies of the proton beam. The proportion of uranium in the mixtures should be around 24% to produce an effective neutron multiplier factor greater than 0.9. The neutron fluxes are much higher than the same calculations for the TRIGA-Mark II reactor model using tungsten target and light water coolant.

Analyzing the Neutron Parameters in the Accelerator Driven Subcritical Reactor Using the Mixture of Molten Pb-Bi as Both Target and Coolant

In this paper, the Accelerator Driven Subcritical Reactor (ADSR) was simulated based on the structure of the TRIGA-Mark II reactor by the MCNPX program. The proton beam interacts on the Pb-Bi molten target with various energy levels from 0.5 GeV to 2.0 GeV. The important neutron parameters to evaluate the operability of ADSR were calculated as: the neutron yields according to various thicknesses of the target and according to the energy of the incident proton beam; the effective neutron multiplication factor for various fuel mixtures, along with its stability for some fuel mixtures; the axial and radial distributions of the neutron flux along with the height and radius of the core. The obtained results had shown a good agreement in using Pb-Bi molten as the interaction target and coolant for ADSR.

Study on Radionuclides from Soil to Onion at Johor and Perak, Malaysia

In this report, the radiological survey of radioactivity measurements in soil and onion and their mobility is carried out which is very important in the environment and several scientific fields. The measurements about the concentrations of activity in soil, leaves and bulbs for onion in the location of Johor and Perak, Malaysia have been carried out using neutron activation analysis (NAA) of TRIGA MARK II research reactor facilities at Nuclear Agency, Bangi, Malaysia. The transfer factors (TFs) of 238U, 232Th and 40K from 6 different natural background soils are studied from soil to onion under natural field conditions. The TFs for onion leaves and bulb are in the range of (6.01-79.2) x 10-3, (1.21-61.4) x 10-3, (1.012-4.265) x 10-1 and 0.028-0.334, 0.017-0.293 and (0.908 -3.685) x10-1for 238U, 232Th, and 40K respectively. There exists a linearity correlation between the dose rate as well as activity concentration of the soils. The observed transfer factor of onion bulbs was usually higher than in leaves.

Decay Nature of Radionuclide Released From Triga Mark-II Reactor

Considering a hypothetical accident, the deposition of radio krypton (85Kr) has been studied that is released from TRIGA MARK-II reactor by its decay behavior. The measurement of radiological ground concentration leads to the study of the emission process of 85Kr nucleus, and the site-specific data related to this measurement have been analyzed later on. In this work, the radioactivity in the reactor core and release rate as well as Gaussian diffusion factor have also been considered. It is observed from the data analysis that the maximum concentration of 85Kr in ground is 1.115E+3 Bq/m2 in South (S) direction. Here, the nuclear binary fission has been presented with the greater probability of production of magic nuclei where the reactions found to be endoergic where a nuclear reaction occurs with the absorption of energy. Doubly magic nuclei like 4He, 16O, 40Ca, and 48Ca have also been identified as fission fragments that follow the nuclear shell closure. The results of this work will be an important guide in the study of radionuclide splitting into several nuclei as well as for accidental scinerio. GUB JOURNAL OF SCIENCE AND ENGINEERING, Vol 7, Dec 2020 P 57-61