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Nishimura, Akihiko; Takenaka, Yusuke*; Furuyama, Takehiro*; Shimomura, Takuya; Terada, Takaya; Daido, Hiroyuki
Journal of Laser Micro/Nanoengineering, 9(3), p.221 - 224, 2014/11
Times Cited Count：0 Percentile：0(Nanoscience & Nanotechnology)Heat resistant FBG sensors were developed by femtosecond laser processing to apply them to high temperature operated piping system of nuclear power plants. The FBG sensor was installed on the surface of a steel blade and a vibration test was conducted to detect the resonant vibration frequency of the vibrating blade. The FBG sensor had the heatproof performance at 600
C. A frequency stabilized sensing system using a tunable laser was tested for structural health monitoring in daily operation of nuclear power plants. The FBG sensor was installed on the surface of a steel blade for vibration induced strain measurements. Welding, brazing, soldering and noble metal powder adhesive were discussed for molding the FBG sensors.
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PNC TN9410 97-013, 111 Pages, 1997/01
Since the 54-rod cluster high-burnup fuel assemblies are planing to be loaded in Fugen, it must be confirmed that the mechanical integrity of the assemblies will be retained during the dwelling period in the reactor core. In the integrity verification, the confirmation that fretting wear, which occurs on fuel cladding surface at the contact with the spacer ring-elements, will not exceed the design margin is important. Accurate measurements of the flow-induced vibration characteristics under the hydraulic condition of coolant simulating the reactor core, especially measurements of the vibration amplitude, is necessary because the vibration amplitude directly affects the fretting wear depth. The flow-induced vibration measurements of the 54-rod cluster high-burnup fuels in which accelerometers were installed, were carried out under the various hydraulic conditions in the Component-Test-Loop (CTL). The results of the measurements are discribed in this papers. From the frequency analysis, the characteristic frequency of the fuel was observed around 105 Hz and 160 Hz. This frequency approximately coincided with that estimated by the fretting wear analysis code. The amplitude of flow-induced vibration was increased with increase in total flow rate and steam quality. Though these tendencies coincided with the results calculated by the analysis code, the amplitude measured at the region of low flow rate tended to be large compared with the calculated values. It was confirmed that this difference can be reduced on the safety side by the modification of the equation in the analysis code. The Paidoussis equation is divided into two terms in this modification, in which one term depending on total flow rate and the other term depending on steam quality, and proper coefficients are determined for each term. Though the amplitudes of flow-induced vibration for this fuel were larger than for either of the 28-rod cluster fuel of Fugen and 36-rod cluster fuel of ATR demonstration ...
Saruta, Koichi; Murata, Atsushi*; Maeno, Koki*; Wakui, Takashi; Naoe, Takashi; Kogawa, Hiroyuki; Li, Y.*; Teshigawara, Makoto; Haga, Katsuhiro; Futakawa, Masatoshi
no journal, ,
In the spallation neutron source at the J-PARC, the mercury target vessel incorporates several countermeasures against cavitation erosion, which reduces the vessel's lifetime. Anomaly detection and diagnosis of the vessel will play an increasingly important role in long-term operation under increased proton beam powers. A laser Doppler vibrometer and a microphone are employed in an attempt to evaluate the correlation of anomalies with the vibration and sound that are excited on the vessel by the incident proton beams, generated by the mercury flow running through the double-wall structure, and caused by the microbubble generator. An overview of the development plan of anomaly detection and diagnosis for the target vessel using vibration and sound measurement is presented and discussed based on preliminary results obtained in water-loop experiments.
