Micro Four-Layer SiC Coating on Matrix Graphite Spheres of HTR Fuel Elements by Two-Step Pack Cementation

2016 ◽  
Vol 99 (11) ◽  
pp. 3525-3532 ◽  
Author(s):  
Ping Zhou ◽  
Xiaoxue Liu ◽  
Hongsheng Zhao ◽  
Ziqiang Li ◽  
Zujie Zheng ◽  
...  
Keyword(s):  
Pack Cementation ◽  
Matrix Graphite ◽  
Fuel Elements

SiC/SiO2 Coating on Matrix Graphite Spheres of HTR Fuel Element Produced by a Two-Step Pack Cementation/High-Temperature Oxidation Process

2016 ◽  
Vol 852 ◽  
pp. 952-958 ◽  
Author(s):  
Ping Zhou ◽  
Zi Qiang Li ◽  
Hong Sheng Zhao ◽  
Kai Hong Zhang ◽  
Xiao Xue Liu ◽  
...  
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Oxidation Process ◽  
Reactor Core ◽  
Isothermal Oxidation ◽  
Pack Cementation ◽  
Temperature Oxidation ◽  
Matrix Graphite ◽  
Fuel Elements

Graphite is one of the most important material for the reactor core and fuel elements of high temperature gas-cooled reactor (HTR). Improving the oxidation resistance of graphite is very essential for the research of new fuel elements and the development of HTR. In this study, a gradient SiC layer of 500~700 μm was prepared on matrix graphite spheres by a two-step pack cementation, and the outer SiO2 layer prepared by the high-temperature oxidation process. The phases, microstructure, bonding strength and oxidation resistance of SiC/SiO2 coated matrix graphite spheres were investigated. The SiC/SiO2 coated matrix graphite spheres were carried on rapid thermal shocking tests from 1773 K to room temperature for 50 times without any cracks. The SiC/SiO2 coated matrix graphite spheres exhibits excellent anti-oxidation properties. No obvious weight loss was found after isothermal oxidation in air at 1273 K for 50 h and the weight gain was less than 1% at 1773 K in air for 50 h due to the oxidation of SiC layer.

SiC/YSiC composite coating on matrix graphite sphere prepared by pack cementation and molten salt

2019 ◽  
Vol 45 (17) ◽  
pp. 21917-21922
Author(s):  
Hui Yang ◽  
Hongsheng Zhao ◽  
Taowei Wang ◽  
Kaihong Zhang ◽  
Ziqiang Li ◽  
...  
Keyword(s):  
Molten Salt ◽  
Composite Coating ◽  
Pack Cementation ◽  
Graphite Sphere ◽  
Matrix Graphite

Effect of FLiBe Infiltration Pressure on Microstructure of Matrix for TMSR Fuel Elements (FEs)

2017 ◽  
Vol 373 ◽  
pp. 189-192
Author(s):  
Hong Xia Xu ◽  
Jun Lin ◽  
Yu Chen ◽  
Bing Chuan Gu ◽  
Bang Jiao Ye ◽  
...  
Keyword(s):  
Positron Lifetime ◽  
X Ray Diffraction ◽  
X Ray ◽  
Positron Annihilation Lifetime ◽  
Infiltration Pressure ◽  
Matrix Graphite ◽  
The Matrix ◽  
Diffraction Patterns ◽  
Fuel Elements ◽  
Scanning Electron

The matrix graphite of fuel elements (FEs) with infiltration of 2LiF-BeF2(FLiBe) at different pressures varying from 0.4 MPa to 1.0 MPa, has been studied by X-ray diffraction (XRD), scanning electron microscope (SEM) and positron annihilation lifetime (PAL) measurement. The result of XRD reveals that diffraction patterns of FLiBe appear in matrix graphite infiltrated with FLiBe at a pressure of 0.8 MPa and 1.0 MPa. The surface morphology from SEM shows that FLiBe mainly distributes within macro-pores of matrix graphite. PAL measurement indicates that there are mainly two positron lifetime components in all specimens:τ1~0.21 ns and τ2 ­~0.47 ns, ascribed to annihilation of positrons in bulk and trapped-positrons at surface, respectively. The average positron lifetime decreases with infiltration pressure, due to the decrease in annihilation fraction of positrons with surface after infiltration of FLiBe into macro-pores.

Stability analysis of SiO2/SiC coatings on matrix graphite for HTR-10 fuel elements

2011 ◽  
Vol 241 (6) ◽  
pp. 2068-2074 ◽  
Author(s):  
Zhi-qiang Fu ◽  
Jian Sun ◽  
Cheng-biao Wang ◽  
Jian-guo Lv ◽  
Chun-he Tang ◽  
...  
Keyword(s):  
Stability Analysis ◽  
Matrix Graphite ◽  
Fuel Elements ◽  
Sic Coatings

The Gasification of Graphite Matrix in Pebble Bed Reactors

2009 ◽  
Author(s):  
Xinli Yu ◽  
Suyuan Yu
Keyword(s):  
High Temperature ◽  
Corrosion Rate ◽  
Fuel Element ◽  
Pebble Bed ◽  
The Core ◽  
Graphite Matrix ◽  
Matrix Graphite ◽  
Element Matrix ◽  
Fuel Elements ◽  
High Temperature Gas

This paper mainly deals with the simulations of graphite matrix of the spherical fuel elements by steam in normal operating conditions. The fuel element matrix graphite was firstly simplified to an annular part in the simulations. Then the corrosions to the matrix graphite in 10 MW High Temperature Gas-cooled Reactor (HTR-10) and the High Temperature Gas-cooled Reactor—–Pebble-bed Module (HTR-PM) were investigated respectively. The results showed that the gasification of fuel element matrix graphite was uniform and mainly occurred at the bottom of the core in both of the reactors in the mean residence time of the spherical fuel elements. This was mainly caused by the designed high temperature at the bottom. The total mass gasified in HTR-PM was much greater than the HTR-10, while it did not mean much severer corrosion occurred there. As it is known the core volume of HTR-PM is much larger than the HTR-10, which will result in much greater consumed graphite even for the same corrosion rate. The steam only lost about 1 to 3 percent after flowing through the cores in both reactors for different steam conditions. The corrosion of graphite became worse when the steam concentrations increased in helium coolant. The results also indicated that the corrosion rate of fuel element matrix graphite tended to increase slightly with the prolonging of the service time.

Dual layer SiC coating on matrix graphite sphere prepared by pack cementation and fluidized-bed chemical vapor deposition

2017 ◽  
Vol 100 (8) ◽  
pp. 3415-3424 ◽  
Author(s):  
Ping Zhou ◽  
Zujie Zheng ◽  
Rongzheng Liu ◽  
Xiaoxue Liu ◽  
Malin Liu ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Fluidized Bed ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Pack Cementation ◽  
Graphite Sphere ◽  
Matrix Graphite
Sign in / Sign up

Export Citation Format

Share Document