2191 R0 XI.M38

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XI.M38 INSPECTION OF INTERNAL SURFACES IN MISCELLANEOUS PIPING AND DUCTING COMPONENTS

Program Description

The program consists of inspections of the internal surfaces of piping, piping components, ducting, heat exchanger components, and other components exposed to potentially aggressive environments. These environments include air, air with borated water leakage, condensation, gas, diesel exhaust, fuel oil, lubricating oil, and any water-filled systems. Aging effects associated with components (except for elastomers and flexible polymeric components) within the scope of Generic Aging Lessons Learned for Subsequent License Renewal (GALL-SLR) Report, aging management program (AMP) XI.M20, “Open-cycle Cooling Water System,” AMP XI.M21A, Closed Treated Water Systems,” and AMP XI.M27, “Fire Water System,” are not managed by this program. Aging effects associated with elastomers and flexible polymeric components installed in open-cycle cooling water, closed-cycle cooling water, ultimate heat sink, and fire water systems are managed by this program in lieu of GALL-SLR Report AMP XI.M20, AMP XI.M21A, and AMP XI.M27. In addition, aging effects associated with fire water system components with only a leakage boundary (spatial) or structural integrity (attached) intended function may be managed by this program.

These internal inspections are performed during the periodic system and component surveillances or during the performance of maintenance activities when the surfaces are made accessible for visual inspection. The program includes visual inspections and when appropriate, surface examinations. For certain materials, such as flexible polymers, physical manipulation or pressurization to detect hardening or loss of strength is used to augment the visual examinations conducted under this program. This program may also be used to manage cracking due to stress corrosion cracking (SCC) in aluminum and stainless steel (SS) components exposed to aqueous solutions and air environments containing halides. If visual inspection of internal surfaces is not possible, then the applicant needs to provide a plant-specific program.

This program, as written, is not intended for use on components in which recurring internal corrosion is evident based on a search of plant-specific operating experience (OE) conducted during the subsequent license renewal application (SLRA) development. If OE indicates that there has been recurring internal corrosion, a plant-specific program will be necessary unless this program, or another new or existing program, includes augmented requirements that address recurring aging effects (e.g., Standard Review Plan for Review of Subsequent License Renewal Applications for Nuclear Power Plants (SRP-SLR) Sections 3.2.2.2.7, 3.3.2.2.7, and 3.4.2.2.6). Following failure due to recurring internal corrosion, this program may be used if the failed material is replaced by one that is more corrosion resistant in the environment of interest, or corrective actions have been taken to prevent recurrence of the recurring internal corrosion.

Evaluation and Technical Basis

1. Scope of Program: This program includes the internal surfaces of piping, piping components, ducting, heat exchanger components, and other components. Inspections are performed when the internal surfaces are accessible during the performance of periodic surveillances or during maintenance activities or scheduled outages. This program is not intended for components where loss of intended function has occurred due to age-related degradation.

For situations in which the material and environment combinations are similar for the internal and external surfaces such that the external surface condition is representative of the internal surface condition, external inspections of components may be credited for managing: (a) loss of material and cracking of internal surfaces of metallic and cementitious components, (b) loss of material, cracking of internal surfaces for polymeric components, and (c) hardening or loss of strength for the internal surfaces of elastomeric materials. When credited, the program describes the component’s internal environment and the credited external component’s environment inspected and provides the basis to justify that the external and internal surface condition and environment are sufficiently similar.

2. Preventive Actions: This program is a condition monitoring program to detect signs of degradation and does not provide guidance for prevention.

3. Parameters Monitored or Inspected: This program manages loss of material, cracking, reduction of heat transfer due to fouling, hardening or loss of strength of elastomeric components, and flow blockage. This program monitors surface conditions or wall thickness to identify loss of material due to corrosion mechanisms for metals and loss of material due to wear for elastomers and polymers. This program also monitors for changes in visual appearance for elastomers and polymers and suppleness to identify changes in hardening of loss of strength of elastomers and flexible polymers.

Periodic surface examinations are conducted if this program is being used to manage cracking in SS or aluminum components. Visual inspections for leakage or surface cracks are an acceptable alternative to conducting surface examinations to detect cracking if it has been determined that cracks will be detected prior to challenging the structural integrity or intended function of the component.

Examples of indicators of aging effects for metallic components include the following:

• Corrosion and surface imperfections
• Loss of wall thickness
• Flaking or oxide-coated surfaces
• Debris accumulation on heat exchanger tube surfaces
• Leakage for detection of cracks on the surfaces of SS and aluminum components exposed to air and aqueous solutions containing halides
• Accumulation of particulate fouling, biofouling, or macro fouling

Examples of indicators of loss of material and changes in material properties of elastomeric and polymeric materials include the following:

• Surface cracking, crazing, scuffing, loss of sealing, and dimensional change (e.g., “ballooning” and “necking”)
• Loss of wall thickness
• Discoloration (evidence of a potential change in material properties that could be indicative of polymeric degradation)
• Exposure of internal reinforcement for reinforced elastomers
• Hardening as evidenced by a loss of suppleness during manipulation where the component and material are appropriate to manipulation

Examples of inspection parameters for cementitious materials include:

• Spalling
• Scaling
• Cracking

4. Detection of Aging Effects: Visual and mechanical (e.g., involving manipulation or pressurization of elastomers and flexible polymeric components) inspections conducted under this program are opportunistic in nature; they are conducted whenever piping, heat exchangers, or ducting are opened for any reason. At a minimum, in each 10-year period during the subsequent period of extended operation, a representative sample of 20 percent of the population (defined as components having the same material, environment, and aging effect combination) or a maximum of 25 components per population is inspected at each unit. Otherwise, a technical justification of the methodology and sample size used for selecting components for inspection is included as part of the program’s documentation. For multi-unit sites where the sample size is not based on the percentage of the population, it is acceptable to reduce the total number of inspections at the site as follows. For two-unit sites, 19 components are inspected per unit and for a three-unit site, 17 components are inspected per unit. In order to conduct 17 or 19 inspections at a unit in lieu of 25, the applicant states in the SLRA the basis for why the operating conditions at each unit are similar enough (e.g., flowrate, chemistry, temperature, excursions) to provide representative inspection results. The basis should include consideration of potential differences such as the following:

• Have power uprates been performed and if so, could more aging have occurred on one unit that has been in the uprate period for a longer time period?
• Are there any systems which have had an out-of-spec water chemistry condition for a longer period of time or out-of-spec conditions occurred more frequently?
• For raw water systems, is the water source from different sources where one or the other is more susceptible to microbiologically influenced corrosion or other aging effects?
• For components exposed to diesel exhaust, have certain diesels more operating more frequently and thus exposed to more cool down transients such that more deleterious materials could accumulate?

Where practical, the inspection includes a representative sample of the system population and focuses on the bounding or lead components most susceptible to aging because of time in service and severity of operating conditions. This minimum sample size does not override the opportunistic inspection basis of this [AMPs| AMP]]. Opportunistic inspections continue even though in a given 10-year period, 20 percent or 25 components might have already been inspected. An inspection of a component in a more severe environment may be credited as an inspection for the specified environment and for the same material and aging effects in a less severe environment (e.g., a condensation environment is more severe than an indoor controlled air environment because the moisture in the former environment is more likely to result in loss of material than would be expected from the normally dry surfaces associated with the latter environment). Alternatively, similar environments (e.g., internal uncontrolled indoor, controlled indoor, dry air environments) can be combined into a larger population provided that the inspections occur on components located in the most severe environment.

Internal visual inspections used to assess loss of material are capable of detecting surface irregularities that could be indicative of an unexpected level of degradation due to corrosion and corrosion product deposition. Where such irregularities are detected for steel components exposed to raw water, raw water (potable), or waste water, follow-up volumetric examinations are performed.

Periodic visual inspections or surface examinations are conducted on SS and aluminum to manage cracking every 10 years during the subsequent period of extended operation when applicable (e.g., see SRP-SLR Sections 3.2.2.2.4 and 3.2.2.2.8). One or more of the following three options may be used to implement the periodic visual inspections or surface examinations:

• Surface examination conducted in accordance with plant-specific procedures.
• ASME Code Section XI VT-1 inspections (including those inspections conducted on non-ASME Code components).
• Visual inspections are conducted where it has been analytically demonstrated that surface cracks can be detected by leakage prior to a crack challenging the structural integrity or intended function of the component. The SLRA includes an overview of the analytical method, input variables, assumptions, basis for use of bounding analyses, and results.

When using this option, cracks can be detected in gas-filled systems by methods such as, but not limited to: (a) for diesel exhaust piping, detecting staining on external surfaces of components; (b) for accumulators and piping connecting the accumulators to components, monitoring and trending accumulator pressures or refill frequency; and (c) soap bubble testing when systems are pressurized. The SLRA includes the specific methods used.

Surface examinations or VT-1 examinations are conducted on 20 percent of the surface area inspected unless the component is measured in linear feet, such as piping. Alternatively, any combination of 1-foot length sections and components can be used to meet the recommended extent of 25 inspections. Opportunistic inspections need not be conducted once the minimum sample inspections are completed.

To determine the condition of internal surfaces of buried and underground components, inspections of the interior surfaces of accessible (i.e., above ground) components may be credited if the accessible and the buried or the underground component material, environment, and aging effects are similar.

Visual inspections include all accessible surfaces. Inspections and tests are performed by personnel qualified in accordance with site procedures and programs to perform the specified task. Unless otherwise required [e.g., by the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code)], inspections follow site procedures that include inspection parameters for items such as lighting, distance, offset, surface coverage, presence of protective coatings, and cleaning processes. The inspection procedures must be capable of detecting the aging effect(s) under consideration. These inspections provide for the detection of aging effects before the loss of component function.

Visual inspection of flexible polymeric components is performed whenever the component surface is accessible. Visual inspection can provide indirect indicators of the presence of surface cracking, crazing, and discoloration. For elastomers with internal reinforcement, visual inspection can detect the exposure of reinforcing fibers, mesh, or underlying metal. Visual and tactile inspections are performed when the internal surfaces become accessible during the performance of periodic surveillances or during maintenance activities or scheduled outages. Visual inspection provides direct indicators of loss of material due to wear, including dimensional change, scuffing, and the exposure of reinforcing fibers, mesh, or underlying metal for flexible polymeric materials with internal reinforcement.

Manual or, physical manipulation or pressurization of flexible polymeric components is used to augment visual inspection, where appropriate, to assess loss of material or strength. The sample size for manipulation is at least 10 percent of accessible surface area, including visually identified suspect areas. For flexible polymeric materials, hardening, loss of strength, or loss of material due to wear is expected to be detectable before any loss of intended function.

5. Monitoring and Trending: Where practical, identified degradation is projected until the next scheduled inspection. Results are evaluated against acceptance criteria to confirm that the sampling bases (e.g., selection, size, frequency) will maintain the components’ intended functions throughout the subsequent period of extended operation based on the projected rate and extent of degradation.

6. Acceptance Criteria: For each component and aging effect combination, the acceptance criteria are defined to ensure that the need for corrective actions is identified before the loss of intended functions. Acceptance criteria are developed from plant-specific design standards and procedural requirements, current licensing basis (CLB), industry codes or standards (e.g., ASME Code Section III, ANSI/ASME B31.1), and engineering evaluation. Acceptance criteria, which permit degradation, are based on maintaining the intended function(s) under all CLB design loads. The evaluation projects the degree of observed degradation to the end of the subsequent period of extended operation or the next scheduled inspection, whichever is shorter. Where practical, acceptance criteria are quantitative (e.g., minimum wall thickness, percent shrinkage allowed in an elastomeric seal). Where qualitative acceptance criteria are used, the criteria are clear enough to reasonably ensure that a singular decision is derived based on the observed condition of the systems, structures, and components (SSC). For example, cracks are absent in rigid polymers, the flexibility of an elastomeric sealant is sufficient to ensure that it will properly adhere to surfaces.

7. Corrective Actions: Results that do not meet the acceptance criteria are addressed in the applicant’s corrective action program under those specific portions of the quality assurance (QA) program that are used to meet Criterion XVI, “Corrective Action,” of Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Appendix B. Appendix A of the GALL-SLR Report describes how an applicant may apply its 10 CFR Part 50, Appendix B, QA program to fulfill the corrective actions element of this AMP for both safety-related and nonsafety-related structures and components (SCs) within the scope of this program.

Additional inspections are conducted if one of the inspections (i.e., opportunistic, minimum sample size for a 10-year interval) does not meet acceptance criteria due to current or projected degradation (i.e., trending) unless the cause of the aging effect for each applicable material and environment is corrected by repair or replacement for all components constructed of the same material and exposed to the same environment. The number of increased inspections is determined in accordance with the site’s corrective action process; however, there are no fewer than five additional inspections for each inspection that did not meet acceptance criteria, or 20 percent of each applicable material, environment, and aging effect combination is inspected, whichever is less. The timing of the additional inspections is based on the severity of the degradation identified and is commensurate with the potential for loss of intended function. However, in all cases, the additional inspections are completed within the interval in which the original inspection was conducted or, if identified in the latter half of the current inspection interval, within the next refueling outage interval. These additional inspections conducted in the next inspection interval cannot also be credited towards the number of inspections in the latter interval. If subsequent inspections do not meet acceptance criteria, an extent of condition and extent of cause analysis is conducted to determine the further extent of inspections. Additional samples are inspected for any recurring degradation to ensure corrective actions appropriately address the associated causes. At multi-unit sites, the additional inspections include inspections at all of the units with the same material, environment, and aging effect combination. If any projected inspection results will not meet acceptance criteria prior to the next scheduled inspection, inspection frequencies are adjusted as determined by the site’s corrective action program.

8. Confirmation Process: The confirmation process is addressed through those specific portions of the QA program that are used to meet Criterion XVI, “Corrective Action,” of 10 CFR 50, Appendix B. Appendix A of the GALL-SLR Report describes how an applicant may apply its 10 CFR 50, Appendix B, QA program to fulfill the confirmation process element of this AMP for both safety-related and nonsafety-related SCs within the scope of this program.

9. Administrative Controls: Administrative controls are addressed through the QA program that is used to meet the requirements of 10 CFR 50, Appendix B, associated with managing the effects of aging. Appendix A of the GALL-SLR Report describes how an applicant may apply its 10 CFR 50, Appendix B, QA program to fulfill the administrative controls element of this AMP for both safety-related and nonsafety-related SCs within the scope of this program.

10. Operating Experience: Inspections of internal surfaces during the performance of periodic surveillance and maintenance activities have been in effect at many utilities in support of plant component reliability programs. These activities have proven effective in maintaining the material condition of plant systems, structures, and components. The elements that comprise these inspections (e.g., the scope of the inspections and inspection techniques) are consistent with industry practice and staff expectations. The applicant evaluates recent OE and provides objective evidence to support the conclusion that the effects of aging are adequately managed.

The review of plant-specific OE during the development of this program is to be broad and detailed enough to detect instances of aging effects that have occurred repeatedly. In some instances, repeatedly occurring aging effects (i.e., recurring internal corrosion) might result in augmented aging management activities. Further evaluation aging management review line items in SRP-SLR Sections 3.2.2.2.7, 3.3.2.2.7, and 3.4.2.2.6, “Loss of Material due to Recurring Internal Corrosion,” include criteria to determine whether recurring internal corrosion is occurring and recommendations related to augmenting aging management activities.

The program is informed and enhanced when necessary through the systematic and ongoing review of both plant-specific and industry OE including research and development such that the effectiveness of the AMP is evaluated consistent with the discussion in Appendix B of the GALL-SLR Report.

References

10 CFR Part 50, Appendix B, “Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants.” Washington, DC: U.S. Nuclear Regulatory Commission. 2016.

EPRI. Technical Report 1007933, “Aging Assessment Field Guide.” Palo Alto, California: Electric Power Research Institute. December 2003.

_____. Technical Report 1009743, “Aging Identification and Assessment Checklist.” Palo Alto, California: Electric Power Research Institute. August 2004.

INPO. Good Practice TS-413, “Use of System Engineers.” INPO 85-033. Atlanta, Georgia: Institute of Nuclear Power Operations. May 1988.

Stress Corrosion Cracking

Operating Experience

Subsequent License Renewal Application - The document submitted by the plant licensee under 10 CFR 54 to extend the operating license of the plant beyond 60 years in 20 year increments. 10 CR 54 has no limits on the number of license extensions that can be approved for a plant.

Subsequent License Renewal - The extension of the original license from 40 years to 60 years is known as License Renewal. Extensions of the license beyond 60 years are known as Subsequent License Renewal.

Aging Management Program

American Society of Mechanical Engineers

Current Licensing Basis - 10 CFR 54.3 under references

Systems, Structures, and Components

Quality Assurance

Electric Power Research Institute

Institute of Nuclear Power Operations