scholarly journals Preliminary Analysis of a Fully Ceramic Microencapsulated Fuel Thermal–Mechanical Performance

Mathematics ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 448 ◽  
Author(s):  
Ping Chen ◽  
Suizheng Qiu ◽  
Shichao Liu ◽  
Yi Zhou ◽  
Yong Xin ◽  
...  
Keyword(s):  
Hoop Stress ◽  
Mechanical Performance ◽  
Chemical Vapor ◽  
Fuel Pellet ◽  
Maximum Temperature ◽  
Sic Ceramics ◽  
Decomposition Point ◽  
Maximum Hoop Stress ◽  
Pressure Water ◽  
Triso Particles

In this paper, a two-dimensional characteristic unit was used to simulate the thermal–mechanical performance of a fully ceramic microencapsulated (FCM) fuel pellet, and the criterion of FCM structure integrity was discussed. FCM structure integrity can be reflected though the integrity of the silicon carbide (SiC) matrix or SiC layers because of the excellent fission retention capability of SiC ceramics. The maximum temperature of the SiC matrix under normal conditions of the pressure water reactor (PWR) environment was about 1390 K, which was lower than the decomposition point of SiC. The maximum hoop stress of the SiC matrix, especially the inner part, was up to about 1200 MPa, and the hoop stress of the non-fuel region part was lower than the inner part, which can be attributed to the deformation of tristructural-isotopic (TRISO) particles. The hoop stress of the SiC layers at the end of life was only about 180 MPa, which is much lower than the strength of the chemical vapor deposition (CVD)-SiC. The failure probability of the SiC layer was lower than 9 × 10−5; thus, the integrity of SiC layers and the fission retention capability were maintained. The structure integrity of FCM fuel was broken because the SiC matrix cracked.

scholarly journals Effect of Structure on the Thermal-Mechanical Performance of Fully Ceramic Microencapsulated Fuel

Computation ◽  
2020 ◽  
Vol 8 (1) ◽  
pp. 13 ◽  
Author(s):  
Yi Zhou ◽  
Zhong Xiao ◽  
Shichao Liu ◽  
Ping Chen ◽  
Hua Pang ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Hoop Stress ◽  
Mechanical Performance ◽  
Maximum Temperature ◽  
Sic Ceramics ◽  
Decomposition Point ◽  
The Matrix ◽  
Maximum Hoop Stress ◽  
Triso Particles ◽  
Effect Of Structure

The effect of non-fuel part size on the thermal-mechanical performance of fully ceramic microencapsulated (FCMTM) Fuel was investigated, and the non-fuel part size was selected according to integrity maintaining of non-fuel part and silicon carbide (SiC) layers. The non-fuel part size can affect the FCMTM temperature and stress distribution greatly by changing the distance between tristructural isotropic (TRISO) particles. The maximum temperature of SiC matrix increased from 1220 K to 1450 K with the non-fuel part size increasing from 100 μm to 500 μm, and the matrix temperature of all the samples was lower than the decomposition point of SiC ceramics. The maximum hoop stress decreased with non-fuel part size, but the inner part exhibiteda crosscurrent trend. The inner part of the SiC matrix lost structure integrity because of the large hoop stress caused by the deformation of TRISO particles, however, the non-fuel parts of FCMTM pellet may maintain their integrity when the non-fuel part size was larger than 300 μm. SiC layers hoop stress increased with non-fuel part size, and the failure probability of SiC layer was lower than 2.2 × 10−4 for the FCMTM pellet with small non-fuel part size. The integrity of non-fuel and SiC layers can be maintained for the FCMTM pellet with the non-fuel part size from 300 μm to 400 μm.

Study on the Thermal-Mechanical Performance of SiC Composites Cladding Under Multiple Conditions

2020 ◽  
Author(s):  
Chunyu Yin
Keyword(s):  
Failure Probability ◽  
Hoop Stress ◽  
Mechanical Performance ◽  
Performance Model ◽  
Operating Conditions ◽  
Analysis Tool ◽  
Operation Conditions ◽  
Sic Fiber ◽  
Maximum Hoop Stress ◽  
Sic Composites

Abstract SiC has become a candidate cladding material of Accident Tolerant Fuels (ATF) due to its excellent irradiation stability and corrosion resistance. However, because SiC is a ceramic material with low toughness, brittle failure is a significant concern. In order to improve the toughness, SiC fiber is required to manufacture multi-layer SiC composites. But the current performance model or analysis tool is not available for SiC composites cladding due to its obviously difference with Zr alloy cladding. On one side, Finite element method was used in this paper to analyze the performance of SiC composites cladding under operation conditions which include normal, transient conditions and LOCA conditions; on the other side, this paper gives the performance of the SiC composites with two layers under multiple operating conditions. The result showed that the temperature was stable and the maximum hoop stress was reached at about 70d under normal condition. The power ramp can increase the cladding temperature and has visible influence on the stress distribution. The hoop stress of the cladding reversed under LOCA condition. The tensile hoop stress on the outer surface significantly increased, which caused the obvious increase of failure probability of monolithic SiC, and the failure probability of SiC layer is significantly increased. The conclusion of the analysis has guiding significance for the theoretical design of SiC composites.

Mechanical Performance of Steam-Cured Self-Compacting Concrete Incorporating Silica Fume and Limestone Powder

2021 ◽  
Vol 56 ◽  
pp. 111-122
Author(s):  
Youcef Ghernouti ◽  
Bahia Rabehi ◽  
Sabria Malika Mansour
Keyword(s):  
Heat Treatment ◽  
Silica Fume ◽  
Mechanical Performance ◽  
Limestone Powder ◽  
Maximum Temperature ◽  
Self Compacting Concrete ◽  
Curing Period ◽  
Heat Treated ◽  
Binder Ratio ◽  
Mechanical Strengths

In this paper, influence of heat treatment on evolution of mechanical strengths at early age, less than 24hours of self-compacting concretes containing limestone powder and silica fume as fine materials was investigated experimentally. Two compositions of self-compacting concrete have been studied; the first is elaborated with silica fume addition and the second with limestone powder, each mixture were prepared with a constant water/binder ratio of 0.39. Concrete samples were either cured in water at (23±1°C), or steam cured at 65°C maximum temperature over six hours (6h) curing period. Tests of mechanical strengths were performed on specimens cooled down slowly to room temperature after heating.The obtained results show that all self-compacting mixtures exhibited satisfying fresh properties and check EFNARC specifications of self-compacting concrete (slump flow diameter higher than 650mm, L-box ratio higher than 80% and sieve stability less than 17%).Mechanical strengths of concrete containing limestone addition are slightly lower than those of concrete based on silica fume at all ages. Moreover, heat treatment generates an improvement of compressive and flexural strength. Interesting compressive strengths are obtained. At 24 hours, after heat treatment, the strengths are already greater than 35 MPa. The values ​​are 37 MPa and 40 MPa for self-compacting concrete containing limestone powder and silica fume respectively compared to 40 MPa and 46 MPa obtained at 7 days for the corresponding non-heat treated concretes. Compressive strength gain of SCCs mixtures with limestone powder and with silica fume, undergoing heat treatment at the age of 24hours is 85% and 75% respectively compared to SCCs mixtures cured in water.

Interaction between two nanoscale elliptical holes with surface tension

2018 ◽  
Vol 24 (5) ◽  
pp. 1556-1566 ◽  
Author(s):  
Shuang Wang ◽  
Cun-Fa Gao ◽  
Zeng-Tao Chen
Keyword(s):  
Surface Tension ◽  
Stress Field ◽  
Hoop Stress ◽  
Elliptical Hole ◽  
Integral Form ◽  
Maximum Hoop Stress ◽  
Stress Boundary Condition ◽  
Elliptical Holes ◽  
Basic Equations ◽  
Stress Boundary

In this paper, the plane problem of two elliptical nanoscale holes with surface tension is investigated. Firstly, the basic equations are given via the complex variable methods. Then, the stress boundary condition caused by surface tension is derived through the integral-form Gurtin–Murdoch model. The problem is finally solved by the conformal mapping along with the series expansion methods. The results show that the stress field decreases as the two holes become further away from each other. When the distance between the two holes is more than three times the sum of their sizes, the interaction between the two holes can be neglected. In addition, the stress field is greatly influenced by the orientation, aspect ratio and size of the holes. The positions of the maximum hoop stress are also discussed. When the two elliptical holes are put close horizontally, the hoop stress around one hole usually obtain its maximum at the endpoint close to the other hole. However, if one elliptical hole is not horizontal, the hoop stress around it will no longer attain its maximum at the endpoints. Another exception is that when one elliptical hole becomes larger, the hoop stress around the smaller hole would tend to achieve a local minimum at the endpoint close to the larger hole.

Single Grain Si TFTs Fabricated at 100oC for Microelectronics on a Plastic Substrate

2007 ◽  
Vol 989 ◽  
Author(s):  
Ming He ◽  
R. Ishihara ◽  
T. Chen ◽  
J.W. Metselaar ◽  
C.I.M. Beenakker
Keyword(s):  
Inductively Coupled Plasma ◽  
Chemical Vapor ◽  
Gate Oxide ◽  
Maximum Temperature ◽  
Plastic Substrate ◽  
Field Effect Mobility ◽  
Laser Crystallization ◽  
Inductively Coupled ◽  
Single Grain ◽  
Excimer Laser Crystallization

AbstractSingle grain TFTs are fabricated at a maximum temperature of 100oC for macroelectronics on a plastic substrate, as Si channels are fabricated at 100oC by combination of excimer laser crystallization and sputtering. The gate oxide is formed at 80°C by inductively coupled plasma enhanced chemical vapor deposition. These TFTs have shown a smaller threshold swing of 0.49 V/dec. and a higher field-effect mobility of 290 cm2/V·s, which can be used to directly fabricate system circuits or a high quality display on a plastic substrate.

Microstructure of SiC–ZrC composite coatings on TRISO particles via fluidized bed chemical vapor deposition

2019 ◽  
Vol 45 (18) ◽  
pp. 24001-24006 ◽  
Author(s):  
Hyeon-Geun Lee ◽  
Daejong Kim ◽  
Ji Yeon Park ◽  
Weon-Ju Kim
Keyword(s):  
Chemical Vapor Deposition ◽  
Fluidized Bed ◽  
Vapor Deposition ◽  
Composite Coatings ◽  
Chemical Vapor ◽  
Triso Particles

Atmospheric Pressure Chemical Vapor Infiltration (CVI) for the Preparation of Biomorphic SiC Ceramics Derived from Paper

2011 ◽  
Vol 11 (9) ◽  
pp. 8416-8419
Author(s):  
Christian Pflitsch ◽  
Benjamin Curdts ◽  
Burak Atakan
Keyword(s):  
Atmospheric Pressure ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Sic Ceramics ◽  
Pressure Chemical ◽  
Vapor Infiltration

Porous SiCnw/SiC ceramics with unidirectionally aligned channels produced by freeze-drying and chemical vapor infiltration

2017 ◽  
Vol 37 (3) ◽  
pp. 915-921 ◽  
Author(s):  
Daoyang Han ◽  
Hui Mei ◽  
Shanshan Xiao ◽  
Junchao Xia ◽  
Jinlei Gu ◽  
...  
Keyword(s):  
Freeze Drying ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Sic Ceramics ◽  
Vapor Infiltration

scholarly journals Vibration of a Cylindrical Tunnel under a Centric Point-Source Explosion

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Yuetang Zhao ◽  
Cheng Chu ◽  
Anastasios Vafeidis ◽  
Jie Li
Keyword(s):  
Hoop Stress ◽  
Integral Transform ◽  
Anisotropic Shell ◽  
Maximum Principal Stress ◽  
Explosive Loading ◽  
Inverse Transformation ◽  
Parameter Study ◽  
Point Explosion ◽  
Order Partial Differential Equation ◽  
Maximum Hoop Stress

Underground tunnels are vulnerable to terrorists’ bombing attacks, which calls for studies on tunnel’s response to internal explosive loading. In this paper, the dynamic response of a cylindrical tunnel to an ideal centric point explosion was treated as an axisymmetric 2-dimensional problem, in which the tunnel was modeled with a continuous anisotropic shell, while the ground medium’s effect was accounted for with linear elastic Winkler springs and the explosive loading described by a temporal and spatial function. The governing equation of the motion is a fourth-order partial differential equation, for which a numerical method combining finite difference with the implicit Newmark-β method was adopted. This method avoided complicated integral transform and numerical inverse transformation, thus allowing efficient parameter study. The maximum radial displacement was found on the cricle of the center of explosive, where hoop stress is the maximum principal stress. The anisotropy showed little influence on maximum hoop stress. Within the range of ground medium’s modulus, minor influence on maximum hoop stress was incurred. This research may be helpful to hazard assessment and protective design for some critical subway tunnels.

Maximum Hoop Stress Evaluation of a Hollow Cylindrical Bulk Superconductor in Field-Cooled Magnetization

2014 ◽  
Vol 792 ◽  
pp. 15-20 ◽  
Author(s):  
Masanori Tsuchimoto
Keyword(s):  
Maxwell Equations ◽  
Hoop Stress ◽  
Three Dimensional ◽  
Stress Distributions ◽  
Bulk Superconductor ◽  
Stress Evaluation ◽  
High Tc ◽  
High Tc Superconductor ◽  
Maximum Hoop Stress ◽  
The Finite Difference Method

Stresses are induced in a bulk high-Tc superconductor (HTS) by field-cooled magnetization. The stress distributions of a hollow cylindrical bulk HTS are numerically studied in the axisymmetric three-dimensional analysis. Shielding current distributions are obtained through a macroscopic numerical simulation with the Maxwell equations and the critical state model. Stress distributions are obtained by using the finite-difference method and iterative calculations. Maximum hoop stress during the field-cooled magnetization is discussed for open and fixed boundary conditions.

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