scholarly journals Coupled Thermomechanical Responses of Zirconium Alloy System Claddings under Neutron Irradiation

2021 ◽  
Vol 11 (3) ◽  
pp. 1308
Author(s):  
Hui Zhao ◽  
Chong Yang ◽  
Dongxu Guo ◽  
Lu Wu ◽  
Jianjun Mao ◽  
...  
Keyword(s):  
Neutron Irradiation ◽  
Neutron Radiation ◽  
Alloy System ◽  
Thermomechanical Coupling ◽  
Fuel Cladding ◽  
Coupling Behavior ◽  
Long Time ◽  
User Material Subroutine ◽  
Fuel Elements ◽  
Zr Alloy

Zirconium (Zr) alloy is a promising fuel cladding material used widely in nuclear reactors. Usually, it is in service for a long time under the effects of neutron radiation with high temperature and high pressure, which results in thermomechanical coupling behavior during the service process. Focusing on the UO2/Zr fuel elements, the macroscopic thermomechanical coupling responses of pure Zr, Zr-Sn, and Zr-Nb binary system alloys, as well as Zr-Sn-Nb ternary system alloy as cladding materials, were studied under neutron irradiation. As a heat source, the thermal conductivity and thermal expansion coefficient models of the UO2 core were established, and an irradiation growth model of a pure Zr and Zr alloy multisystem was built. Based on the user material subroutine (UMAT) with ABAQUS, the current theoretical model was implemented into the finite element framework, and the consequent thermomechanical coupling behavior under irradiation was calculated. The distribution of temperature, the stress field of the fuel cladding, and their evolution over time were analyzed. It was found that the stress and displacement of the cladding were sensitive to alloying elements due to irradiated growth.

scholarly journals Effect of Cd and SPD on structure, physical, mechanical, and operational properties of alloy of Cu-Cr-Zr

2020 ◽  
Vol 59 (1) ◽  
pp. 506-513
Author(s):  
Denis A. Aksenov ◽  
Georgiy I. Raab ◽  
Rashid N. Asfandiyarov ◽  
Vladimir I. Semenov ◽  
Lev Sh. Shuster
Keyword(s):  
Wear Resistance ◽  
Structure Refinement ◽  
Alloy System ◽  
Environmental Safety ◽  
Structural Refinement ◽  
Industrial Systems ◽  
Ultrafine Grained ◽  
Positive Effect ◽  
Complete Processing ◽  
Zr Alloy

AbstractAn increase in the service life of electrical products from copper and its alloys is directly related to an increase in the wear resistance of materials. Structural refinement and alloying with cadmium are known to have a positive effect on the strength characteristics and wear resistance of copper, which makes it possible, with a Cd content of 1% by weight, to increase the wear resistance of copper several times, but cadmium is considered an environmentally unsafe element. In this regard, the paper presents the results of studies of a widely used Cu-Cr-Zr alloy system in the ultrafine-grained (UFG) state, micro-alloyed with cadmium (0.2%, weight), in order to improve physical, mechanical, and operational properties, as well as environmental safety. Severe plastic deformation, providing structure refinement to ~150 nm, and microalloying with cadmium of a Cu-Cr-Zr system alloy, after a complete processing cycle, provides a tensile strength of 570±10 MPa and 67% electrical conductivity. At the same time, the abrasion resistance increases by 12 and 35% relative to the industrial systems Cu-Cd and Cu-Cr-Zr, respectively. The obtained characteristics are very promising for improving the operational properties of continuous welding tips, collector plates, and contact wires operating under conditions of intense wear.

scholarly journals Features of methods for monitoring the fuel cladding tightness in lead-cooled fast breeder reactors

2021 ◽  
Vol 7 (4) ◽  
pp. 319-325
Author(s):  
Anastasiya V. Dragunova ◽  
Mikhail S. Morkin ◽  
Vladimir V. Perevezentsev
Keyword(s):  
Liquid Metal ◽  
Fission Products ◽  
General Description ◽  
Fuel Cladding ◽  
Reactor Plant ◽  
Reactor Unit ◽  
Basic Principles ◽  
Gaseous Fission ◽  
Breeder Reactors ◽  
Fuel Elements

To timely detect failed fuel elements, a reactor plant should be equipped with a fuel cladding tightness monitoring system (FCTMS). In reactors using a heavy liquid-metal coolant (HLMC), the most efficient way to monitor the fuel cladding tightness is by detecting gaseous fission products (GFP). The article describes the basic principles of constructing a FCTMS in liquid-metal-cooled reactors based on the detection of fission products and delayed neutrons. It is noted that in a reactor plant using a HLMC the fuel cladding tightness is the most efficiently monitored by detecting GFPs. The authors analyze various aspects of the behavior of fission products in a liquid-metal-cooled reactor, such as the movement of GFPs in dissolved and bubble form along the circuit, the sorption of volatile FPs in the lead coolant (LC) and on the surfaces of structural elements, degassing of the GFPs dissolved in the LC, and filtration of cover gas from aerosol particles of different nature. In addition, a general description is given of the conditions for the transfer of GFPs in a LC environment of the reactor being developed. Finally, a mathematical model is presented that makes it possible to determine the calculated activity of reference radionuclides in each reactor unit at any time after the fuel element tightness failure. Based on this model, methods for monitoring the fuel cladding tightness by the gas activity in the gas volumes of the reactor plant will be proposed.

Occupational Exposure to Neutrons at the Beloyarsk NPP

ANRI ◽  
2021 ◽  
Vol 0 (3) ◽  
pp. 16-26
Author(s):  
Mariya Pyshkina ◽  
Aleksey Vasil'ev ◽  
Aleksey Ekidin ◽  
Evgeniy Nazarov ◽  
Anton Pudovkin ◽  
...  
Keyword(s):  
Occupational Exposure ◽  
Energy Distribution ◽  
Flux Density ◽  
Nuclear Fuel ◽  
Neutron Irradiation ◽  
Radiation Flux ◽  
Spent Nuclear Fuel ◽  
Neutron Radiation ◽  
Dose Equivalent ◽  
Equivalent Rate

Studies of the energy distribution of neutron radiation at the workplaces of the Beloyarsk NPP were carried out. At 1 and 2 power units, occupational exposure of neutron irradiation occurs during operations for loading spent nuclear fuel into special railway carriage. At power units 3 and 4, operations accompanied by neutron irradiation can be divided into 3 groups: (1) work in rooms adjacent to the reactor core; (2) manipulation of radioisotope neutron sources; (3) work with fresh and spent nuclear fuel. Based on the data obtained on the energy distribution of the neutron radiation flux density, the ‘true’ values of the ambient dose equivalent rate H*(10), the individual dose equivalent rate Hp(10) and the integral neutron radiation flux density at individual workplaces were determined. For each group of workplaces, Fluence-toambient dose equivalent conversion coefficients are determined, which lie in the range from 12 to 295 pSv⋅cm2. Correction factors for individual thermoluminescent dosimeters, taking into.

scholarly journals Stability Improvement of Flexible Shallow Shells Using Neutron Radiation

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3187
Author(s):  
Anton V. Krysko ◽  
Jan Awrejcewicz ◽  
Irina V. Papkova ◽  
Vadim A. Krysko
Keyword(s):  
Temperature Field ◽  
Neutron Irradiation ◽  
Microelectromechanical Systems ◽  
Neutron Radiation ◽  
Middle Surface ◽  
Aviation Industry ◽  
Irradiation Effect ◽  
Structural Members ◽  
Mems Devices ◽  
Shallow Shells

Microelectromechanical systems (MEMS) are increasingly playing a significant role in the aviation industry and space exploration. Moreover, there is a need to study the neutron radiation effect on the MEMS structural members and the MEMS devices reliability in general. Experiments with MEMS structural members showed changes in their operation after exposure to neutron radiation. In this study, the neutron irradiation effect on the flexible MEMS resonators’ stability in the form of shallow rectangular shells is investigated. The theory of flexible rectangular shallow shells under the influence of both neutron irradiation and temperature field is developed. It consists of three components. First, the theory of flexible rectangular shallow shells under neutron radiation in temperature field was considered based on the Kirchhoff hypothesis and energetic Hamilton principle. Second, the theory of plasticity relaxation and cyclic loading were taken into account. Third, the Birger method of variable parameters was employed. The derived mathematical model was solved using both the finite difference method and the Bubnov–Galerkin method of higher approximations. It was established based on a few numeric examples that the irradiation direction of the MEMS structural members significantly affects the magnitude and shape of the plastic deformations’ distribution, as well as the forces magnitude in the shell middle surface, although qualitatively with the same deflection the diagrams of the main investigated functions were similar.

Formation of amorphous phase in the binary Cu−Zr alloy system

2006 ◽  
Vol 12 (3) ◽  
pp. 207-212 ◽  
Author(s):  
O. J. Kwon ◽  
Y. C. Kim ◽  
K. B. Kim ◽  
Y. K. Lee ◽  
E. Fleury
Keyword(s):  
Amorphous Phase ◽  
Alloy System ◽  
Zr Alloy

Quaternary and Quinary Ni-based Amorphous Alloys in the Ni-Zr-Ti-X (X=Al, Si, P) and Ni-Zr-Ti-Si-Y (Y=Sn, Mo, Y) Systems

2000 ◽  
Vol 644 ◽  
Author(s):  
M.H. Lee ◽  
S. Yi ◽  
T.G. Park ◽  
W.T. Kim ◽  
D.H. Kim
Keyword(s):  
Amorphous Alloys ◽  
Alloy System ◽  
Continuous Heating ◽  
Liquid Region ◽  
Undercooled Liquid ◽  
Bulk Amorphous Alloys ◽  
Glass Forming ◽  
Structural Application ◽  
Crystallization Mode ◽  
Zr Alloy

AbstractNew Ni-based bulk amorphous alloys in the alloy system Ni-Zr-Ti-X (X=Al, Si, P) and Ni-Zr- Ti-Si-Y (Y=Sn, Mo, Y) were developed through systematic alloy design based upon the empirical rules for high glass forming ability (GFA). Additions of a small amount of Si and/or Sn to a ternary Ni-Ti-Zr alloy are very effective to increase GFA as well as the undercooled liquid region (ΔTX). Changes in crystallization mode during continuous heating of amorphous phase and lowered liquidus temperature by quaternary and quinary additions are associated with the enhanced GFA and the enlarged ΔTx. Development of new Ni-based amorphous alloys with high GFA and large ΔTx expands structural application of amorphous alloys.

scholarly journals Acute, Low-Dose Neutron Exposures Adversely Impact Central Nervous System Function

2021 ◽  
Vol 22 (16) ◽  
pp. 9020
Author(s):  
Peter M. Klein ◽  
Yasaman Alaghband ◽  
Ngoc-Lien Doan ◽  
Ning Ru ◽  
Olivia G. G. Drayson ◽  
...  
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Charged Particle ◽  
Neutron Irradiation ◽  
Time Course ◽  
Memory Performance ◽  
Neutron Radiation ◽  
Long Term Potentiation ◽  
Radiation Environment ◽  
Elevated Exposure

A recognized risk of long-duration space travel arises from the elevated exposure astronauts face from galactic cosmic radiation (GCR), which is composed of a diverse array of energetic particles. There is now abundant evidence that exposures to many different charged particle GCR components within acute time frames are sufficient to induce central nervous system deficits that span from the molecular to the whole animal behavioral scale. Enhanced spacecraft shielding can lessen exposures to charged particle GCR components, but may conversely elevate neutron radiation levels. We previously observed that space-relevant neutron radiation doses, chronically delivered at dose-rates expected during planned human exploratory missions, can disrupt hippocampal neuronal excitability, perturb network long-term potentiation and negatively impact cognitive behavior. We have now determined that acute exposures to similar low doses (18 cGy) of neutron radiation can also lead to suppressed hippocampal synaptic signaling, as well as decreased learning and memory performance in male mice. Our results demonstrate that similar nervous system hazards arise from neutron irradiation regardless of the exposure time course. While not always in an identical manner, neutron irradiation disrupts many of the same central nervous system elements as acute charged particle GCR exposures. The risks arising from neutron irradiation are therefore important to consider when determining the overall hazards astronauts will face from the space radiation environment.

scholarly journals Interaction studies between U-Zr alloy system and ceramic plasma-spray coated layer at elevated temperature

2018 ◽  
Vol 5 (0) ◽  
pp. 192-195
Author(s):  
Ki-Hwan Kim ◽  
Ki-Won Hong ◽  
Hoon Song ◽  
Seok-Jin Oh ◽  
Jeong-Yong Park
Keyword(s):  
Elevated Temperature ◽  
Plasma Spray ◽  
Alloy System ◽  
Interaction Studies ◽  
Coated Layer ◽  
Zr Alloy
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