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PNC TJ9164 98-006, 150 Pages, 1998/02
Feasibility of a in-vessel acoustic detection system, which is used to detect boiling noise of sodium in a reactor vessel of FBR, was evaluated by means of SOSUM (Sound source Super-imposed Method) code. In 1997 Fy propagation of abnormal sound (ex, boiling noise) was evaluated. In 1998 Fy, detail simulation model in which fuel pins with wire are involved, was evaluated. In order to reduce calculation time, dipole model was adopted in the simulation. Adequacy of the dipole simulation model was confirmed by comparison with the simulated result acquired by normal elements division model. With the result of this study, difference of propagation was less than about 6 %,. and detecting sound source's position in reactor vessel was evaluated to be possible by Synthetic Aperture Focusing Technique with about 4 detecting points.
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PNC TJ9164 97-014, 50 Pages, 1997/03
Feasibility of a in-vessel acoustic detection system which is used to detect boiling noise of sodium in a reactor vessel of FBR, was evaluated by means of SOSUM(Sound Source Super-imposed method) code. The whole simulation model is consist of two steps. First one is the analysis of the sound propagation within the fuel assemblies. The second one is the analysis of the sound propagation from the fuel assemblies outlet to the acoustic detector installed in the upper plenum in Reactor. First a pulse wave was used in the simulation of the sound propagation in order to confirm the adequacy of the simulation. The propagation of white noise, which is considered to be resemble to an actual boiling noise, was used as a sound source to evaluate and to extract subjects, the feasibility of the in-vessel acoustic detection system. Based on a result of the analysis, pressure deceleration of the sound source is about 1/25000, and wave shape can be preserved after propagation. So it is expected that the in-vessel acoustic detection system will be feasible.
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PNC TJ9164 96-018, 48 Pages, 1996/03
Acoustic sensing technique is regarded as one of means of to detect the unusual conditions detection in-a reactor vessel of FBR. This study aims at investigating data which are useful to develop the microphone which can be used continuously under sodium in a reactor vessel, and have good sensitivity and high temperature resistance. The acoustic characteristics of the existing high temperature microphone was investigated. And the shape and fixation of element and the inner structure of the microphone were confirmed by means of X-ray photographing. The arrangement, materials and environment resistance of the existing microphone were conjectured and subjects of the future development were picked up based on the above investigation's results.
