Research on Nondestructive Examination of Jacket Sections for CFETR Central Solenoid Model Coil

Abstract

The central solenoid model coil (CSMC) is a large superconducting “model” coil, which is responsible for developing and verifying the key manufacturing methods of the China Fusion Engineering Test Reactor. Therefore, all subcomponents have very strict requirements, including the conductors which are cable-in-conduit conductor (CICC) type. The jacket section as an important component of the CSMC CICC is circular-in-square type, which is nonmagnetic stainless steel. Severe requirements not only high mechanical performances but also the size of initial defects in the jacket section were specified. Based on the linear elastic fracture mechanics, maximum acceptable defect sizes inside the jacket material have been estimated. Phased array ultrasonic test (PAUT) supplemented with eddy current test (ECT) were studied and developed for nondestructive examination. The defects inside the jacket section can be detected by PAUT with 11 runs by 4 probes. The defects on inner surfaces can be detected by ECT. Focal laws on PAUT and parameters of ECT are also discussed in this paper.