Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
*; *; *; *
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.
*; *; *; *
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.
*; *; *; *; *
PNC TJ9164 97-004, 40 Pages, 1997/03
As a part of the development of ISI(In-Service Inspection), the investigations regarding the inspect ion equipment which can observe the distortion of core assemblies under operating condition with ultrasonic measuring technique were performed as follows. (1)The method in order to measure distortion of core assemblies under turbulent outlet sodium flow of the core assemblies was investigated. An improved arrangement of ultrasonic sensors on the equipment was also investigated in this study. (2)A conceptual design of a test rig and conditions of the in-water test, in which performance of the measuring system of core assemblies distortions will be evaluated, were investigated. (3)The conditions of irradiation test of the heat-proof ultrasonic sensors were revised according to the result regarding the ultrasonic sensor's arrangement. The neutron flux condition and the arrangement of the test elements in a test rig were also revised. So it was confirmed that the irradiation test conditions can be realized in the severance-rig within a fuel rack.
*; *; *
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.
*; *; *; *; *
PNC TJ9164 96-013, 62 Pages, 1996/03
As a part of the development of ISI (In-Service Inspection), the investigations regarding the inspection equipment which can observe the distortion of core assemblies under operating condition with ultrasonic measuring technique were performed as follows. (1)The test elements of high temperature ultrasonic sensor for the irradiation test in operating condition were manufactured. And it was confirmed that the elements had good performance under 500 
C air condition. (2)The specifications of drive mechanism, cable and connector were clarified. And structure of the inspection equipment was investigated in consideration to conditions of actual plant in JOYO. (3)As the condition of irradiation test, the neutron flux which should be irradiated and the arrangement of the test elements in a test rig were estimated. It was confirmed that the irradiation test condition can be realized in the severance-rig within a fuel lack.
*; Sekiguchi, Mineo*; *; *; *
PNC TJ9164 95-012, 50 Pages, 1995/03
As a part of the development of the in-service inspection and repair(ISI & R) technology of FBR, study on examination equipments as visual method to verify in-vessel structures and assemblies was conducted. The objects of the study were higher resolution equipments using ultrasonic transducer technology to examine top area of assemblies in core support structure and parts of the core support structure where entrance nozzles of assemblies were inserted and withdrawn when refueling in 'JOYO'. As the result of the study, basic specification and structures of transducers and signal processing units, and conceptual design of basic structure of drive mechanics for the transducers were derived. The items and plan of the development of the equipments were made.
