The effect of fabrication parameters on the inner microfissure in the Zr-lined cladding tube has been investigated. The results were as follows: 1. The Q-value during cold pilgering is an important factor for inner fissures. When the Qvalue is larger than 1.5, the tube is subject to the favorable effect on the fissure. 2. The inner fissures are dependent on grain size of the Zr liner. The smaller grain of the mother tube before cold pilgering has a good effect on the inner fissure of the tube after cold pilgering. 3. Pickling before cold pilgering has proven to be important for decreasing defects in the bore of the Zr-lined tube.
These results are very useful for improving and assuring the quality of the Zr-lined cladding tube.