Advances in NDE Techniques at Complex,

N. Saibaba Nuclear Fuel Complex, ECIL PO, Hyderabad- 500062

Abstract

Department of Atomic Energy (DAE) makes valuable contributions in planning and achieving energy security in . Nuclear Fuel Complex (NFC), a constituent unit of DAE, has mandate for fabrication of the nuclear fuel, different types of sub-assemblies, core structural components and steam generator tubing etc. for power generation through different types of nuclear reactors namely PHWRs, BWRs and PFBR. The integrity of the nuclear fuel and structural components is crucial as they are exposed to severe environment of radiation and temperature during their residence in . Non-destructive Examination (NDE) during fabrication of these materials is critical, as it provides assurance for safe and continuous operation of reactor during its lifetime. At NFC, almost all the conventional NDE techniques are used for ensuring quality of critical components like fuel tubes, sheets, bars, large diameter pressure tubes and thin-walled calandria tubes etc during their manufacture. In order to meet the unique requirements of high sensitivity & resolution and complex shape of the components, many NDE techniques have been developed in-house. At NFC, more than a few millions of components are being subjected to non-destructive testing every year, thus requiring automation in testing. The NDE of components in such large numbers results in effluents which need to be minimised by adopting suitable echo-friendly technologies.

Some of the advancements in NDE at NFC include development of

‹ Automated machine vision system for inspection of surface defects in UO 2 pellets. ‹ Automated Ultrasonic testing of PHWR end-cap welds. ‹ Automated Helium backfilling and leak testing of PHWR fuel bundles with Helium recirculation system. ‹ Digital radiography for evaluation of fuel tube to end-plug welds in BWR fuel and PFBR sub assemblies. ‹ High speed tube-rotating UT system for very-long-length tubes for steam generator applications. ‹ Use of ultrasonic phased array for defect detection and visualization in thin wall stainless steel tubes of D9 material. ‹ Multi-frequency eddy current examination of tubes of zirconium alloys, ferritic, austenitic and ferritic-austenitic steels. ‹ Use of infra-red thermography in the on-line monitoring of fabrication processes like tube drawing, pilgering etc. ‹ Application of DC saturation field for suppression of magnetic Barkhausen noise for ferritic materials ‹ X-ray based residual stress measurement in tube-wall after ‘U’ bending and glass bead peening.

This paper summarizes some of the advances in the NDE techniques that have been used during fabrication of various components at NFC which have resulted in improvement of throughput, quality, recovery and reduced effluents. *****