Method of preparing fuel cladding having an alloyed zirconium barrier layer

A cladding tube having an outer substrate, an intermediate zirconium barrier layer, and a zirconium-based inner liner having alloying elements, the substrate, barrier layer, and inner liner each having interior and exterior circumferential surfaces, the cladding tube being made by a process comprising the following steps:

• (a) bonding the zirconium barrier layer exterior circumferential surface to the substrate interior circumferential surface;
• (b) bonding the inner liner outer circumferential surface to the zirconium barrier layer inner circumferential surface;
• and
• (c) conducting a diffusion anneal after steps (a) and (b) at a time and temperature sufficient to cause the alloying elements from the inner liner to diffuse into the barrier layer to form a diffusion layer containing a concentration of alloying elements that decreases from the interior circumferential surface of the barrier layer to a location interior to the barrier layer where there is substantially no alloying elements, wherein the alloying elements in the diffusion layer impart corrosion resistance to the barrier layer.

A method of making a cladding tube having an outer substrate, an intermediate zirconium barrier layer, and an inner liner having alloying elements, the substrate, barrier layer, and inner liner each having interior and exterior circumferential surfaces, the method comprising the following steps:

• (a) bonding the zirconium barrier layer exterior circumferential surface to the substrate interior circumferential surface and bonding the inner liner outer circumferential surface to the zirconium barrier layer inner circumferential surface to form a tubeshell;
• (b) conducting a diffusion anneal at a time and temperature sufficient to cause the alloying elements from the inner liner to diffuse into the barrier layer to form a diffusion layer containing a concentration of alloying elements that decreases from the interior circumferential surface of the barrier layer to a location interior to the barrier layer where there is substantially no alloying elements;
• (c) performing two or more cold work steps, each followed by a stress relief or recrystallization anneal;
• and
• (d) heating at most about the outer 33% of the outer substrate into the alpha plus beta or beta phase and then cooling to produce a distribution of fine precipitates in the outer region of the substrate, wherein the alloying elements in the diffusion layer impart corrosion resistance to the barrier layer.