For zircaloy mill products, NDE starts from extruded and machined billets. They are inspected visually, dimensionally and ultrasonically before second extrusion or hot rolling as the case may be. Hollow extruded blanks for Zr-Nb pressure tubes or slabs for welded tubes are tested ultrasonically as process control check and accepted if good or after rework if necessary. The blanks for fuel tubes are pilgered successively with interstage anneal to final fuel sheath size and large volumes of sheathing is examined by high speed immersion ultrasonic testing on 100% basis for flaws, wall and OD, Visual examination is another control where highly experienced personnel stop any unacceptable surface discontinuities moving down the process line.

The mandrels for pilgering and dies for extrusion are magnetic particle tested if suspected visually.

Ultrasonic immersion testing using shear waves is used for qualifying the integrity of sheets before they are formed into seam welded tubes. The seam welded tubes are used as structurals and as reactivity mechanism tubes in the core of the reactor. Micro-focus radiography with video-imaging and normal X-ray radiography using film are used for these thin walled seam-welded tubes during production and at final stage. The bar material that goes for closure plugs for fuel rods undergoes eddy current and ultrasonic checks. The pressure tubes which hold the fuel bundles in the reactor are qualified at billet stage after extrusion and at successive stages upto final using ultrasonic testing. Ultrasonic testing is used for process control at intermediate stages, and at final stage the tubes undergoes on 100% basis both Ultrasonic and Eddy current flaw detection, wall thickness measurement and OD measurement. Boroscopy on ID is utilised as supplementary NDT tool.