LIFE EXTENSION | DRESDEN LICENCE RENEWAL representative connector sample size and they will be
tested to detect increased resistance of the connection. One-time inspection of selected components will verify:
the system-wide effectiveness of an aging management programme that is designed to prevent or minimise aging to the extent that it will not cause the loss of intended function during the subsequent period of extended operation; the insignificance of an aging effect; and that long-term loss of material will not cause a loss of intended function for steel components exposed to environments that do not include corrosion inhibitors as a preventive action.
The programme will include: determination of the sample
size of components to be inspected; identification of the inspection locations in the system or component based on the potential for the aging effect to occur; determination of the examination technique, including acceptance criteria that would be effective in managing the aging effect for which the component is examined; and an evaluation of the need for follow-up examinations to monitor progression if age-related degradation is found that could jeopardize an intended function before the end of the subsequent period of extended operation.
Requires enhancement BWR vessel internals programme manages the effects of cracking and evaluations determined that supplemental inspections are not necessary during extended operation, The BWR Vessel Internals program will be enhanced to limit the scope expansion exemption applying to large diameter jet pump diffuser, adapter and lower ring welds that are inspected by UT. Flow-accelerated corrosion programme manages wall thinning caused by flow accelerated corrosion (FAC). It will be extended to reassess infrequently used piping systems excluded from the scope of the program to ensure adequate bases exist to justify this exclusion for periods of extended operation beyond 60 years. Bolting integrity programme manages aging for loss of
preload, cracking, and loss of material of safety-related and non-safety-related closure bolting on pressure-retaining components.
It will be enhanced to clarify guidance that proper selection of bolting material and lubricants, and appropriate installation torque or tension to prevent or minimize loss of bolting preload and cracking of high- strength bolting is a requirement and to perform periodic visual inspections of a representative sample of bolting for bolted joints where leakage is difficult to detect, such as bolting in joints that are submerged, in systems that are not normally pressurised, and in systems containing air or gas. It will revise procedures on visual examinations of bolted joints to include inspection parameters such as lighting, distance, and offset and will require additional bolts to be inspected when samples do not meet acceptance criteria Open-cycle cooling water system aging management
programme will additionally include at least 20 inspections for recurring internal corrosion in the raw water systems every 24 months; a comparison to the design minimum allowable wall thickness to determine the acceptability of the component for continued use; and a determination of re-inspection interval. Closed treated water systems programme manages
loss of material, cracking, and reduction of heat transfer in piping, piping components, tanks, and heat exchangers exposed to a closed cycle cooling water environment. It will add opportunistic visual inspections and sample-based periodic inspections using techniques (visual, surface, or volumetric) capable of detecting loss of material, cracking, and fouling. The reactor vessel surveillance programme manages
the loss of fracture toughness due to neutron irradiation embrittlement of the reactor vessel beltline materials. The programme is part of the BWRVIP Integrated Surveillance Program which is providing fluence and materials data. The programme will be enhanced to comply with 10 CFR 50 Appendix H.
The buried and underground piping and tanks
condition monitoring programme addresses piping and tanks constructed of any material, including carbon steel, stainless steel, polymers, aluminium, carbon fibre reinforced polymer, asbestos cement and cast iron. Annual cathodic protection surveys are conducted. In addition, the programme will include direct visual inspections: of one 10’ (3m) section of buried stainless steel piping, two 10’ sections of buried polymeric piping and two 10’ segments of buried carbon steel piping, selected based on susceptibility to degradation and consequences of failure. Condition inspections be carried out on steel and stainless-steel piping including annual monitoring of the cathodic protection system and inspection of at least 25% of the internal surface of some buried fuel oil tanks. An ASME aging management programme of metallic
Above: Dresden Clean Energy Centre’s two nuclear reactors in Morris, Illinois, can generate up to 1,845 MWe
26 | June 2024 |
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pressure-retaining components of steel containments will be enhanced with surface or enhanced visual examination to detect cracking, as well as volumetric examination of containment metal shell surfaces that are inaccessible from one side, if there is shell corrosion An ASME aging management programme of inspection of piping and component supports will be augmented with periodic evaluations of the acceptability of inaccessible areas of supports (for example, portions of supports encased in concrete, buried underground, or encapsulated by guard pipe), if warranted by conditions. Volumetric examination will be added if additional high-strength bolting is installed.
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