R&D of multi-frequency ECT algorithms for FBR SG tubes

高速炉の蒸気発生器伝熱管用多重周波渦電流探傷演算アルゴリズムに関する研究開発

Mihalache, O. ; 山口 智彦 ; 白濱 卓馬; 上田 雅司 

Mihalache, O.; Yamaguchi, Toshihiko; Shirahama, Takuma; Ueda, Masashi

The adherence of sodium on the external surface of steam generator tubes (SGs) of Fast Breeder Reactors (FBR) adds an additional level of complexity in the in-service inspection (ISI) of SGs using eddy current testing (ECT). The paper focusses on research and development (R&D) of novel multi-frequency (MF) algorithms, based on ECT signals, special developed and tuned to enhance the signal from defects located on external SG tube surface and to suppress electromagnetic noise from the conductive sodium and SG support plates. The application of the MF algorithm is investigated using both three-dimensional finite element (FEM) simulations and experimental measurements from SG tubes soaked and then drained of sodium, in a sodium tank mock-up.