Non-destructive testing technique was developed for embedded hardware using acoustic emission sensors. In this technique, AE sensor records the acoustic vibration generated by striking the embedded hardware with a hammer. The fixed state of the embedded hardware is judged from the vibration time of the embedded hardware recorded by the AE sensor and the frequency distribution of the acoustic signal. Mockup tests and FEM analysis were carried out in order to verify the effectiveness of the technique....
英字タイトル:
Embedded hardware inspection using AE sensor Part1 Mockup tests

Non-destructive testing technique was developed for embedded hardware using acoustic emission sensors. In this technique, the fixed state of the embedded hardware can be judged from the vibration time and the frequency distribution of the acoustic signal. In this report, we introduce inspection method and analysis method at site and the application result of JNFL by nondestructive inspection technology of embedded hardware using AE sensor....
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Embedded hardware inspection using AE sensor Part2 Site inspection

The maintenance of valves used in nuclear facilities (check valves, ball valves, gate valves, butterfly valves, etc.) is carried out by daily checking and overhaul. However, it is not easy to diagnose the inside status of these valves such as open-close performance and internal leakage. In this report, our approaches are shown to develop valve diagnosis by acoustic measurement using AE (Acoustic Emission) sensor through test loop examinations and the field applications....
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Development of valve diagnosis using AE sensor

Non-destructive testing technique was developed for embedded plates using phased-array ultrasonic testing (PAUT). The bending angle of their studs was quantitatively estimated by using the sector scan of PAUT, which is usually difficult by using conventional UT. In addition, this technique is capable of visualizing the weld shape of the stud by using the linear scan of PAUT. Mockup tests were carried out in order to verify the effectiveness of the technique....
英字タイトル:
Development of Testing Technique on Embedded Plates Using Phased-Array Ultrasonic Testing

In the reprocessing facility of Japan Nuclear Fuel Limited, we had advanced the plant walk-down to put all equipment in the facility under our management. Throughout the plant walk-down, SANGENSYUGI (Going to the fields and observing equipment directory to understand their actual conditions) was thoroughly upheld. The trigger of the plant walk-down is the revelation, occurred in August 2017, of the fact that a part of static devices of important equipment to safety had not been under the appropriate mainten...
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The efforts or the improvements of maintenance activities in the Rokkasho Reprocessing Plant

Non-destructive evaluation technique was developed to identify the integrity of embedded hardware using digital hammering inspection with AE (Acoustic Emission) sensor. The inspection can diagnose the fixed state of the embedded hardware in terms of its natural frequency and vibration duration. Mockup tests were conducted to investigate the relationship between the change in vibration duration and the fixed state under various loads including external tensile loads and thermal loads when welding supports on...
英字タイトル:
Improvement of the efficiency of hammering inspection using AE sensor for embedded hardware 2

Non-destructive evaluation technique was developed for embedded hardware using hammering inspection with AE (Acoustic Emission) sensor. The integrity of the studs welded on the hardware is judged from both the vibration duration of the embedded hardware and the frequency analysis of the vibration signal. The hammering inspection has been applied to the reprocessing plant of JNFL (Japan Nuclear Fuel Limited) for three years and we are now planning the improvement of the efficiency of the inspection in variou...
英字タイトル:
Improvement of the efficiency of hammering inspection using AE sensor for embedded hardware

日本原燃株式会社再処理施設において、 2015年 8月に一般共同溝の蒸気配管を支持する埋込金物（図 1参照）に浮き上がりが発見され、調査の結果、ジベルが欠損しており不適切な施工であることが判明した 1。埋込金物の不適合事象の対応として再処理施設の埋込金物数量約 52.8万枚を調査した結果、適切な施工記録が確認された埋込金物と点検対象外の埋込金物の合計が約 35.2万枚、残り 17.6万枚については施工記録が不十分であるため、現品点検による健全性評価が必要と判断した。現品点検では、ジベルの欠損を確認する方法として超音波探傷（ UT）検査を実施し、その結果、一般共同溝の UT検査結果では規格外の埋込金物が約 200 枚確認された 1。一方で、 UT検査では埋込金物のジベル直上にセンサを設置し測定する必要があるが、耐震サポート等が設置されていることから、 UT検査用のセンサをジベル直上に配置できず、 UT検査できないジベルが多数存在している。これらの UT検査できないジベルについては、欠損していない事を証明できないため、著者らは AE（Acoustic Emission）センサを用いた打音検査（以下では AE打音検...