Inspection of nuclear storage tanks using remotely deployed ACFMT

Abstract

Stainless steel nuclear storage vessels offer a challenge to NDT techniques when inspection is required to detect cracking in vessel walls and floors. Medium to high levels of radiation are often a barrier to manually deployed methods and access generally can be difficult. TSC Inspection Systems have developed an advanced underwater alternating current field measurement technique (ACFMT) array probe for Cete Apave to inspect the welds between plates of these types of vessel for surface breaking cracks. The array probe is deployed by a crawler and can gain access to areas where the clearance between the vessel and obstructions is only 35 mm. This enables inspection even under the fuel rod crates. The ACFMT array covers a width of 50 mm, the whole weld cap and toes, with each pass and the data is displayed in real-time and stored for future reference. The system offers both detection and sizing of defects for length and depth using its mathematical algorithms without the need for prior calibration by the operator.