Above: One of the control rooms at the Dresden plant Source: ANS


or surface cracks will be performed to detect cracking of stainless steel components exposed to a diesel exhaust environment as the detection of staining on the component external surface demonstrates the ability to detect leakage. An evaluation will be performed that demonstrates that cracks will be detected prior to challenging the structural integrity or intended function of the component. At least once in each 10-year period of extended


operation, a sample (20% of the population) will be inspected, along with opportunistic inspections. For certain materials, such as flexible polymers, physical manipulation or pressurisation to detect hardening or loss of strength will augment visual examinations. A thermal aging embrittlement of cast austenitic


stainless steel (CASS) programme will provide assurance that the intended functions of the reactor coolant pressure boundary components – piping components and pump casings – with the potential for significant thermal aging embrittlement will be maintained. A screening methodology based on casting method, molybdenum content, and ferrite percentage will identify components to undergo qualified visual inspections, such as enhanced visual examination or qualified ultrasonic testing methodology, or a component- specific flaw tolerance evaluation. Note that reactor vessel internal components fabricated


from CASS are already managed by another aging management programme. The selective leaching programme will monitor


components whose materials are susceptible to selective leaching and in their specific environment. Susceptible materials include grey cast iron, malleable iron, ductile iron, and copper alloys containing greater than 15% zinc. It includes one-time inspections in closed cycle cooling water and treated water environments, but operating experience has not revealed selective leaching in these environments. Opportunistic and periodic inspections consist of visual and mechanical examination techniques (for grey cast iron, malleable iron, and ductile iron components), as well as periodic non-destructive and destructive examinations for determining physical properties such as the degree of dealloying, depth of dealloying, through-wall thickness, and chemical composition, for components exposed to raw water, waste water, and soil environments. Inspections and tests will be conducted to determine whether loss of material will affect the ability of the components to perform their intended function through the subsequent period of extended operation. The ASME Code Class 1 small-bore piping programme augments existing ASME Code, Section XI requirements for small-bore piping and systems of 1-4” (2.4-10 cm)


diameter. It includes volumetric or destructive examination of a sample of full penetration (butt) welds and partial penetration (socket) welds in Class 1 piping to manage cracking due to stress corrosion cracking or thermal or vibratory fatigue loading. The programme will verify that degradation is not occurring and validate the effectiveness of existing programmes and practices. The extent and schedule for volumetric examination


is based on Dresden plant-specific operating experience, which demonstrates that cracking of Class 1 small- bore welds is not occurring and that actions have been implemented to effectively mitigate the causes of the single instance of past cracking. Internal coatings/linings for in-scope piping, piping


components, heat exchangers, and tanks programme manages degradation of internal coatings/linings exposed to raw water, treated water, fuel oil and condensation. For buried cement-lined fire water piping, opportunistic inspections will be performed in addition to flow tests and internal piping inspections. There are no piping or components with internal coatings/linings in the program scope that are exposed to air, closed-cycle cooling water, waste water, lubricating oil or treated borated water. It includes visual inspection where loss of coating or lining integrity could impact the component’s or downstream component’s functions. Peeling and delamination is not acceptable. Blisters are


limited to a few intact small blisters that are completely surrounded by sound coating/lining bonded to the substrate with blister size or frequency not increasing between inspections. Minor cracks in cementitious coatings are acceptable provided there is no evidence of debonding. All other degraded conditions are evaluated by a coatings specialist. Electrical insulation for inaccessible instrument and


control cables not subject to 10 CFR 50.49 environmental qualification requirements applies to inaccessible or underground instrument and control cables that are within the scope of licence renewal and potentially exposed to significant moisture (three days of wetting or submergence over a continuous period). Manholes, handholes and associated accessible conduit ends are inspected for water accumulation and the water is removed as needed. Electrical cable connections not subject to 10 cfr 50.49


environmental qualification requirements requires testing of a representative sample of electrical connections prior to the subsequent period of extended operation. The results will be evaluated to determine if there is a need for subsequent periodic testing on a 10-year frequency. Twenty per cent of each connector type population is a


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