Abstract : A new technique of temperature and strain measurement using fiber Bragg grating (FBG) optical fiber sensor at high temperature in irradiation environment was proposed, in which interrogation of FBGs is carried out based on optical time-domain reflectometry (OTDR). Heating test results showed that stable temperature measurement can be done at 600°C and the reflectance of FBG can be kept constant up to 1000°C. From the strain measurement test on a cantilever, multi-point strain measurement c...
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Development of the FBG sensor for strain and temperature monitoring of high-temperature pipelines of nuclear power reactors

An experiment of post-irradiated annealing for ion-irradiated stainless steel model alloy was performed to investigate the mechanical changes and microstructural changes by using nano-indenter, TEM observation and 3DAP measurement. The thermal stability and barrier factor strength of solute atom clusters formed by ion irradiation were evaluated....
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Study about irradiation hardening contribution of solute atomic cluster formed in ion-irradiated stainless steel model alloys

In order to investigate that the hardening with δ hydrides generation in Zr was influenced by the relationship between the slip plane of dislocation and the habit plane of δ hydride, the EBSD analysis, the nano-indentation hardness test and the in-situ TEM observation during tensile test were performed. In the case when the δ hydrides of crystal orientation relationship (habit plane) of (0001)α plane//{111}δ plane and <2-1-10>α direction//<110>δ direction were precipitated in the Zr sample, the hardening of...
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The hardening amount evaluation with δ hydrides generation in Zr by using the nano-indentation hardness test and microstructure observation

In-situ TEM observation during tensile deformation test for an ion-irradiated SUS316L steel was performed to investigate a dislocation interaction with irradiation-induced defect clusters. Hardening contribution of irradiation-induced defect clusters such as solute atom clusters was estimated with experimental methodology using dislocation pinning behavior during tensile deformation. The utilization method of the in-situ TEM observation technique for hardening evaluation for irradiated materials was also di...
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Hardening contribution of irradiation defects in ion-irradiated stainless steels using in-situ observation tensile deformation

An irradiation hardening behavior in a SUS316 steel was investigated from the ultra-micro hardness test after hydrogen ion irradiation as parameters of irradiation dose and indentation depth systematically. Based on the crystal orientation of the sample surface specified using EBSD, comparative evaluation of ultra-micro hardness in the same crystal orientation relationship was performed. Cross-sectional TEM observation of ion-irradiated microstructure under the indentation after deformation was performed to...
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Effect for irradiation hardening due to interaction between deformation process and microstructural evolution during nano-indenter examination

To verify the effect of hardened surface on stress corrosion cracking (SCC) of 316L, characteristics of cracked BWR core shroud have been investigated by means of microstructures. At the inner surface of core shroud where grinding was done, fine grains were observed at the surface thin layer. Furthermore, deformation-induced slip-line field including extensive deformation-twins was observed in the harden ed surface region. In contact with corrosion products on the shroud surface, intensive Ni enrichment a...
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Microstructural Analyses of hardened surface in BWR core shroud made of 316L

The phase decomposition behaviour of an experimental High-chromium Ferritic steel containing 40 wt.% chromium (Fe-40Cr) irradiated with 8 MeV electrons was studied by positron annihilation lifetime (PAL) measurements and coincidence Doppler broadening (CDB) of positron annihilation radiation measurements. Electron irradiation at 100 and at 475 ?C were performed on the specimens to nominally 0.03 to 0.3X10-3 dpa. The rapid increase of W-parameter obtained from the specimen irradiated at 100 ?C is most like...
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Effect of Thermal Aging and Electron Irradiation on Microstructure Changes of High Chromium Steels