scholarly journals Application of the collective model to determine some rotational bands of 239U nucleus

Author(s):  
Nguyen An Son ◽  
Le Viet Huy ◽  
Pham Ngoc Son

238U material is component in fuels of nuclear reactor core. Understanding properties and structure of 238U nucleus is necessary before simulating and designing nuclear reactor. Besides that, the study of nuclear reaction is necessary to identify the specific characteristics of nucleus, it is the most effective experimental method up to now. However, in order to explain the properties of nuclear structure, in addition to study of the nuclear reaction, nuclear structure models and its theory must be used. There are many nuclear structure models to solve those properties of nucleus. This paper presents application of the Collective Model to determine some rotational bands of 239U nucleus, using Prompt gamma neutron activation analysis method (PGNAA). Experiment is performed at channel No.2 of Dalat Research Reactor (DRR), using Filtered Thermal Neutron Beam and Compton Suppression Spectroscopy with High – Purity Germanium detector (HPGe). The results have found 11 rotational bands of 239U nucleus. This work is very necessary for the research of nuclear structure which controls material technology by itself.

2019 ◽  
Vol 14 (9) ◽  
pp. 59
Author(s):  
Nguyen An Son ◽  
Le Viet Huy ◽  
Pham Ngoc Son ◽  
Ho Huu Thang

140La is created from the thermal neutron capture reaction of 139La, which is the product of the fission reaction. It makes some effects into the components of the nuclear reactor core. Understanding the properties and structure of 140La is important in operating the nuclear reactor. Besides that, nuclear structure models are very effective in explaining the properties of nuclear structure. There are many nuclear structure models to solve those problems, such as Liquid Drop Model, Shell Model, Fermi Model, etc. Among them, the Collective Model has been very successful in describing the variety of nuclear properties, especially energy levels in deformed nuclei that the Shell Model and the Liquid Drop Model does not apply. This paper presents the application of the Collective Model to determine some vibrational bands of 140La nucleus. This experiment is performed at channel No.2 of Dalat Research Reactor (DRR), Prompt gamma neutron activation analysis method (PGNAA) is used. The result has found 8 vibrational bands of 140La nucleus.  It’s quite relevant to the theoretical calculation. The deviations are less than 1.6 %.


2019 ◽  
Vol 21 (2) ◽  
pp. 115 ◽  
Author(s):  
K. Samarkhanov ◽  
E. Batyrbekov ◽  
M. Khasenov ◽  
Yu. Gordienko ◽  
Zh. Zaurbekova ◽  
...  

At the present time the direct nuclear energy conversion into optical radiation is realized in gas media in which filling of energy levels takes place in the low-temperature plasma (nuclear-excited plasma) induced by ionizing radiation. The research of optical radiation of the nuclear-excited plasma induced by products of nuclear reactions is interest for development of an alternative outlet method of energy from the nuclear reactor, creation of control and regulating bodies for parameters of nuclear reactors as well as creation of one of diagnostics of high-temperature plasma in fusion reactors. The purpose of this work was to obtain new experimental data about processes of nuclear energy conversion into optical radiation with the optimal gas media having high coefficient of nuclear energy conversion into optical radiation and also with a possibility of outlet method of energy from the nuclear reactor core. In this article, description of the reactor experimental bench (LIANA) and the experiment scheme, the irradiating ampoule device (AD) with surface source of charged particles is provided, and the procedure of reactor experiment is presented. This paper presents the results of the reactor experiments of studying the spectral-luminescent characteristics of unary noble gases (Ne, Ar, Kr, Xe) and binary Kr-Xe gas mixture in a 200–975 nm spectral range with ionization gaseous media by products of 6Li(n,α)T nuclear reaction under irradiation at research water-cooled heterogeneous reactor (the IVG.1M).


2014 ◽  
Vol 17 (4) ◽  
pp. 36-41
Author(s):  
Son An Nguyen ◽  
Lanh Dang ◽  
Thang Huu Ho

The research nuclear reactions is necessary to identify the specific characteristics of nucleus, It is the most effective experimental method up to now. However, in order to explain the properties of nuclear structures, in addition to the study of the nuclear reactions, nuclear structure models to explain experimental data and its theory must be used. There are many nuclear structure models to solve those properties of nucleus. This paper presents a collective model application to identify some of rotational bands and vibrational bands of 152Sm and 152Gd nucleus which have the decayed beta of 152Eu source.


Author(s):  
Han Zhang ◽  
Fu Li

The traditional solution of the coupled neutronics/ thermal-hydraulics problems has typically been performed by solving the individual field separately and then transferring information between each other. In this paper, full implicit integrate solution to the coupled neutronics/ thermal-hydraulic problem is investigated. There are two advantages compared with the traditional method, which are high temporal accuracy and stability. The five equations of single-phase flow, the solid heat conduction and the neutronics are employed as a simplified model of a nuclear reactor core. All these field equations are solved together in a tightly coupled, nonlinear fashion. Firstly, Newton-based method is employed to solve nonlinear systems due to its local second-order convergence rate. And then the Krylov iterative method is used to solve the linear systems which are from the Newton linearization. The two procedures above are the so-called Newton-Krylov method. Furthermore, in order to improve the performance of the Krylov method, physics-based preconditioner is employed, which is constructed by the physical insight. Finally, several Newton-Krylov solution approaches are carried out to compare the performance of the coupled neutronics / thermal-hydraulic equations.


2002 ◽  
Vol 29 (10) ◽  
pp. 1225-1240 ◽  
Author(s):  
Mehrdad Boroushaki ◽  
Mohammad B. Ghofrani ◽  
Caro Lucas

2021 ◽  
Vol 30 (5) ◽  
pp. 66-75
Author(s):  
S. A. Titov ◽  
N. M. Barbin ◽  
A. M. Kobelev

Introduction. The article provides a system and statistical analysis of emergency situations associated with fires at nuclear power plants (NPPs) in various countries of the world for the period from 1955 to 2019. The countries, where fires occurred at nuclear power plants, were identified (the USA, Great Britain, Switzerland, the USSR, Germany, Spain, Japan, Russia, India and France). Facilities, exposed to fires, are identified; causes of fires are indicated. The types of reactors where accidents and incidents, accompanied by large fires, have been determined.The analysis of major emergency situations at nuclear power plants accompanied by large fires. During the period from 1955 to 2019, 27 large fires were registered at nuclear power plants in 10 countries. The largest number of major fires was registered in 1984 (three fires), all of them occurred in the USSR. Most frequently, emergency situations occurred at transformers and cable channels — 40 %, nuclear reactor core — 15 %, reactor turbine — 11 %, reactor vessel — 7 %, steam pipeline systems, cooling towers — 7 %. The main causes of fires were technical malfunctions — 33 %, fires caused by the personnel — 30 %, fires due to short circuits — 18 %, due to natural disasters (natural conditions) — 15 % and unknown reasons — 4 %. A greater number of fires were registered at RBMK — 6, VVER — 5, BWR — 3, and PWR — 3 reactors.Conclusions. Having analyzed accidents, involving large fires at nuclear power plants during the period from 1955 to 2019, we come to the conclusion that the largest number of large fires was registered in the USSR. Nonetheless, to ensure safety at all stages of the life cycle of a nuclear power plant, it is necessary to apply such measures that would prevent the occurrence of severe fires and ensure the protection of personnel and the general public from the effects of a radiation accident.


Author(s):  
Xiaomeng Dong ◽  
Zhijian Zhang ◽  
Zhaofei Tian ◽  
Lei Li ◽  
Guangliang Chen

Multi-physics coupling analysis is one of the most important fields among the analysis of nuclear power plant. The basis of multi-physics coupling is the coupling between neutronics and thermal-hydraulic because it plays a decisive role in the computation of reactor power, outlet temperature of the reactor core and pressure of vessel, which determines the economy and security of the nuclear power plant. This paper develops a coupling method which uses OPENFOAM and the REMARK code. OPENFOAM is a 3-dimension CFD open-source code for thermal-hydraulic, and the REMARK code (produced by GSE Systems) is a real-time simulation multi-group core model for neutronics while it solves diffusion equations. Additionally, a coupled computation using these two codes is new and has not been done. The method is tested and verified using data of the QINSHAN Phase II typical nuclear reactor which will have 16 × 121 elements. The coupled code has been modified to adapt unlimited CPUs after parallelization. With the further development and additional testing, this coupling method has the potential to extend to a more large-scale and accurate computation.


1998 ◽  
Vol 4 (S2) ◽  
pp. 772-773
Author(s):  
J.T. Busby ◽  
E.A. Kenik ◽  
G.S. Was

Radiation-induced segregation (RIS) is the spatial redistribution of elements at defect sinks such as grain boundaries and free surfaces during irradiation. This phenomenon has been studied in a wide variety of alloys and has been linked to irradiation-assisted stress corrosion cracking (IASCC) of nuclear reactor core components. However, several recent studies have shown that Cr and Mo can be enriched to significant levels at grain boundaries prior to irradiation as a result of heat treatment. Segregation of this type may delay the onset of radiation-induced Cr depletion at the grain boundary, thus reducing IASCC susceptibility. Unfortunately, existing models of segregation phenomena do not correctly describe the physical processes and therefore are grossly inaccurate in predicting pre-existing segregation and subsequent redistribution during irradiation. Disagreement between existing models and measurement has been linked to potential interactions between the major alloying elements and lighter impurity elements such as S, P, and B.


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