New facilities for zircaloy nuclear fuel cladding tubes and product quality

In June, 1981, the new factory for the yearly production of 500,000 m of Zircaloy fuel cladding tubes was completed in Kobe Steel Ltd. In this new factory, computer control systems are adopted in several places, and especially in a vacuum annealing furnace, the system contributes to improve the uniformity of temperature. Also in the final pickling facility, an ultrasonic dimension measuring system is incorporated for the pickling of internal surfaces to automatically measure and adjust the dimensions. The quality of the products mass-produced in this new factory has been confirmed to be higher as compared with the products of high quality level obtained by small quantity production in the existing factory. The Zircaloy cladding tubes for BWRs made by Kobe Steel are superior to the imported tubes, and have contributed to the prevention of fuel breaking in nuclear power stations. Two years have elapsed since the start of operation of this new factory, and both the quality and quantity have attained the expected results. The fundamental concept to construct the new factory, the layout of buildings, the main installations and the results of the quality of products are reported. A 25 VMR finishing rolling mill, a roll straightening machine, an external grinder, the final pickling facility, an ultrasonic flaw detector and a vacuum annealing furnace are described. (Kako, I.)