Cracking of cladding can result from

• A. Unsatisfactory water chemistry controls or monitoring
• B. Proper water chemistry controls or monitoring
• C. Adequate materials handling during outages
• D. Effective corrosion product management

Answer: (A)

Cracking of cladding is driven by hydrogen embrittlement that arises from corrosion reactions in the reactor coolant. If water chemistry controls or monitoring are unsatisfactory, the corrosion rate increases, more hydrogen is generated, and hydrogen can diffuse into the zirconium alloy cladding under stress. This hydrogen uptake promotes hydride formation and cracking of the cladding, especially under the irradiation and thermal conditions inside the reactor.

Maintaining proper water chemistry controls reduces hydrogen production and oxide growth, lowering the likelihood of such cracking. While good material handling during outages or effective corrosion product management help with overall integrity and cleanup, they do not address the primary chemical pathway that leads to cladding cracking as directly as inadequate water chemistry controls.