Material degradation and ageing in BWR service and their mitigation
Materials and Corrosion Issues in the Primary Coolant Circuit of Boiling Water Reactors

During prolonged operation, the (synergistic) effects of the thermo-mechanical and thermo-hydraulic loading, increased temperatures, reactor coolant and the irradiation field can progressively result in:

• changes of material properties (strength, toughness, corrosion resistance, etc.)

• initiation and propagation of cracks (SCC, fatigue)

• changes of component dimension/geometry (FAC, plastic deformations, distortions, etc.)

These slowly progressing, operation-induced changes or degradation/damage in the materials are called physical ageing. There are around 50 different potential degradation mechanism in BWRs and PWRs, with the most important being SCC, FAC, fatigue and irradiation...