Obtaining the neutronic and thermal hydraulic parameters of the VVER-1000 Bushehr nuclear reactor core by coupling nuclear codes

Abstract

In this research, the simulation of one-sixth of the VVER-1000 reactor core is carried out by the WIMS-D4 nuclear code, based on the symmetry of the core and information obtained from the Final Safety Analysis Report. The atomic densities of some important nuclear materials and fission poisons are calculated by the WIMS-D4 code at the end of the first fuel cycle. In addition, the cross sections of some nuclides are obtained by WIMS-D4, and they are transferred into the CITATION code as inputs. In the next stage, neutron flux and reactor power are calculated by the CITATION code in Cold Zero Power and Hot Full Power status, and subsequently the heat flux of the core is obtained. Then the results are returned again into the extended program cycle. Finally, the heat flux of the core is inputted into the COBRA code, and the temperatures of fuel, clad and coolant are calculated along the various distances applying the COBRA thermal hydraulic code, through the results of the CITATION code and also initial data as default created from the Final Safety Analysis Report. In conclusion, there are some interesting outcomes resulting form the obtained results.

Applying mathematical equations and computer programming to obtain transferred energy into body tissue

“…The problem is to compute the energy of recoiled nucleus, and it involves applying the neutron diffusion equation. 11,12 Therefore, the maximum rate of 2 1 E E (or on the other hand minimum lost energy) occurs whenever θ=0 and the maximum lost energy will occur in the case of .…”

“…The suitable reactors those which include low power reactors generally, using the core as a source of neutrons and also existing moderator might be used for radiation therapy, if the mono energy neutron source is not accessible. 1,2 The boric acid solution moderator might be suitable for the spectrum measurement of an epithermal neutron irradiation field. Thus, computation and modeling of the delivered energy before practical treatment is also recommended.…”

Finding Out and Exploration of Two New Equations for Calculating the Dead-time of Neutron Detectors and the Energy of Slow-downed Neutrons

“…Additionally, the high LET of protons is also because of fast neutron scattering. But, the low LET of gamma radiations is a result of capturing the thermal neutrons and tissue and also hydrogen atoms [ 1 H(n,γ) 2 H] [18]. By detecting each proton or an alpha particle, there can infer the existence of a neutron.…”