2191 R0 XI.M41

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XI.M41 BURIED AND UNDERGROUND PIPING AND TANKS

Program Description

This aging management program (AMP) manages the aging of the external surfaces of buried and underground piping and tanks. It addresses piping and tanks composed of any material, including metallic, polymeric, and cementitious materials. This program manages aging through preventive, mitigative, inspection, and in some cases, performance monitoring activities. It manages applicable aging effects such as loss of material and cracking.

Depending on the material, preventive and mitigative techniques may include external coatings, cathodic protection, and the quality of backfill. Also, depending on the material, inspection activities may include electrochemical verification of the effectiveness of cathodic protection, nondestructive evaluation of pipe or tank wall thicknesses, pressure testing of the pipe, performance monitoring of fire mains, and visual inspections of the pipe or tank from the exterior.

This program does not provide aging management of selective leaching. The Selective Leaching program of the Generic Aging Lessons Learned for Subsequent License Renewal (GALL-SLR) Report AMP XI.M33 is applied in addition to this program for applicable materials and environments.

Evaluation and Technical Basis

1. Scope of Program: This program manages the effects of aging of the external surfaces of buried and underground piping and tanks constructed of any material including metallic, polymeric, and cementitious materials. The term “polymeric” material refers to plastics or other polymers that comprise the pressure boundary of the component. The program addresses aging effects such as loss of material and cracking. The program also manages loss of material due to corrosion of piping system bolting within the scope of this program. The Bolting Integrity program (GALL-SLR Report AMP XI.M18) manages other aging effects associated with piping system bolting. This program does not provide aging management of selective leaching. The Selective Leaching of Materials program (GALL-SLR Report AMP XI.M33) is applied in addition to this program for applicable materials and environments.

2. Preventive Actions: Preventive actions utilized by this program vary with the material of the tank or pipe and the environment (e.g., air, soil, concrete) to which it is exposed. There are no recommended preventive actions for titanium alloy, super austenitic stainless steels, and nickel alloy materials. Preventive actions for buried and underground piping and tanks are conducted in accordance with Table XI.M41-1 and the following:

Table XI.M41-1. Preventive Actions for Buried and Underground Piping and Tanks
Material	Buried	Underground
Stainless steel	C, B	None
Steel	C, CP, B	C
Copper alloy	C, CP, B	C
Aluminum alloy	C, CP, B	None
Cementitious	C, CP, B	None
Polymer	B	None
C: Coatings; CP: Cathodic Protection; B: Backfill

1. For buried stainless steel or cementitious piping or tanks, coatings are provided based on the environmental conditions (e.g., stainless steel in chloride containing environments). Applicants provide justification when coatings are not provided. Coatings are in accordance with Table 1 of National Association of Corrosion Engineers (NACE) SP0169-2007 or Section 3.4 of NACE RP0285-2002 as well as the following coating types: asphalt/coal tar enamel, concrete, elastomeric polychloroprene, mastic (asphaltic), epoxy polyethylene, polypropylene, polyurethane, and zinc.
2. For buried steel, copper alloy, and aluminum alloy piping and tanks and underground steel and copper alloy piping and tanks, coatings are in accordance with Table 1 of NACE SP0169-2007 or Section 3.4 of NACE RP0285-2002.
3. Cathodic protection is in accordance with NACE SP0169-2007 or NACE RP0285-2002. The system is operated so that the cathodic protection criteria and other considerations described in the standards are met at every location in the system for which cathodic protection is credited. System monitoring is conducted annually with a grace period of one to two months; however, in each calendar year, system monitoring is conducted at least once. The equipment used to implement cathodic protection need not be qualified in accordance with Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Appendix B.
4. Cathodic protection is supplied for reinforced concrete pipe and prestressed concrete cylinder pipe. Applicants provide justification when cathodic protection is not provided.
5. Critical potentials for cathodic protection:
   1. To prevent damage to the coating or base metal (e.g., aluminum), the limiting critical potential should not be more negative than −1,200 mV.
   2. Where an impressed current cathodic protection system is utilized with prestressed concrete cylinder pipe, steps are taken to avoid an excessive level of potential that could damage the prestressing wire. Therefore, polarized potentials more negative than -1,000 mV relative to a copper/copper sulfate reference electrode (CSE) are avoided to prevent hydrogen generation and possible hydrogen embrittlement of the high-strength prestressing wire.
   3. Depending on the environment, steel (in a carbonate-bicarbonate environment) and stainless steel components can experience stress corrosion cracking dependent on the cathodic protection polarization level, temperature, pH, etc. If these conditions are applicable, the applicant describes the conditions and alternative cathodic protection levels in the subsequent license renewal application (SLRA).
   4. Any further over-protection limits are defined by the applicant and managed during surveillance activities. The use of excessive polarized potentials on externally coated pipelines should be avoided.
6. Backfill is consistent with NACE SP0169-2007 Section 5.2.3 or NACE RP0285-2002, Section 3.6. The staff considers backfill that is located within 6 inches of the component that meets ASTM D 448-08 size number 67 (size number 10 for polymeric materials) to meet the objectives of NACE SP0169-2007 and NACE RP0285-2002. For stainless steel and cementitious materials, backfill limits apply only if the component is coated. For materials other than aluminum alloy, the staff also considers the use of controlled low strength materials (flowable backfill) acceptable to meet the objectives of NACE SP0169-2007.
7. Alternatives to the preventive actions in Table XI.M41-1 are as follows:
   1. A broader range of coatings may be used if justification is provided in the SLRA.
   2. Backfill quality may be demonstrated by plant records or by examining the backfill while conducting the inspections described in the “detection of aging effects” program element of this AMP.
   3. For fire mains installed in accordance with National Fire Protection Association (NFPA) NFPA® 24, preventive actions beyond those in NFPA 24 need not be provided if: (a) the system undergoes either a periodic flow test in accordance with NFPA 25; (b) the activity of the jockey pump (e.g., number of pump starts, run time) is monitored as described in “detection of aging effects” program element of this AMP; or (c) an annual system leakage rate test is conducted.
   4. Failure to provide cathodic protection in accordance with Table XI.M41-1 may be acceptable if justified in the SLRA. The justification addresses soil sample locations, soil sample results, the methodology and results of how the overall soil corrosivity was determined, pipe to soil potential measurements and other relevant parameters.
      
      If cathodic protection is not provided for any reason, the applicant reviews the most recent 10 years of plant-specific operating experience (OE) to determine if degraded conditions that would not have met the acceptance criteria of this AMP have occurred. This search includes components that are not in-scope for license renewal if, when compared to in-scope piping, they are similar materials and coating systems and are buried in a similar soil environment. The results of this expanded plant-specific OE search are included in the SLRA.

3. Parameters Monitored or Inspected:

1. Visual inspections of: (a) the external surface condition of buried or underground piping or tanks; (b) the external surface condition of associated coatings; or (c) external surfaces of controlled low strength material backfill are performed. Monitoring of the surface condition of the component is conducted to detect indications of aging effects described in 3.b. Monitoring of the surface condition of coatings is conducted to determine if the coatings are intact, well-adhered, and otherwise sound; such that aging effects would not be expected for the base material of the component. Monitoring of the external surfaces of controlled low strength material backfill is conducted to detect potential cracks that could admit groundwater to the surface of the component.
2. Visual inspections of the external surface condition of the component should detect:
   1. loss of material due to general, pitting, crevice, and microbiologically influenced corrosion (MIC) for copper alloy and steel components;
   2. loss of material due to pitting and crevice corrosion for aluminum alloy and titanium alloy components;
   3. loss of material due to pitting and crevice corrosion, and MIC for stainless steel, super austenitic, and nickel alloy components;
   4. loss of material due to wear for polymeric materials;
   5. cracking due to chemical reaction, weathering, or settling for cementitious materials;
   6. cracking or blistering due to water absorption for high-density polyethylene and fiberglass components;
   7. cracking due to corrosion of reinforcement for reinforced concrete pipe; and
   8. loss of material due to delamination, exfoliation, spalling, popout, or scaling for cementitious materials.
3. Volumetric nondestructive examination techniques as well as pit depth gages or calipers may be used for measuring wall thickness as long as: (a) they have been determined to be effective for the material, environment, and conditions (e.g., remote methods) during the examination; and (b) they are capable of quantifying general wall thickness and the depth of pits. Wall thickness measurements are conducted to detect potential loss of material.
4. Inspections for cracking due to stress corrosion cracking for steel (in a carbonate-bicarbonate environment), stainless steel and susceptible aluminum alloy materials utilize a method that has been determined to be capable of detecting cracking. Coatings that: (a) are intact, well-adhered, and otherwise sound for the remaining inspection interval; and (b) exhibit small blisters that are few in number and completely surrounded by sound coating bonded to the substrate do not have to be removed. Inspections for cracking are conducted to assess the impact of cracks on the pressure boundary function of the component.
5. Pipe-to-soil potential and the cathodic protection current are monitored for steel, copper alloy, and aluminum alloy piping and tanks in contact with soil to determine the effectiveness of cathodic protection systems.
6. When using alternatives to excavated direct visual examination of fire mains, appropriate inspection parameters are used in order to detect indications of fire main leakage. For example:
   1. During periodic flow test, a reduction in available flow rate.
   2. For jockey pump monitoring, an increase in the number of pump starts or run time of the pump.
   3. During annual system leakage rate testing an increase in unaccounted flow leak rates (i.e., the leakage path could be through a valve disc and seat, which is not pertinent to this AMP).

4. Detection of Aging Effects: Methods and frequencies used for the detection of aging effects vary with the material and environment of the buried and underground piping and tanks. Inspections of buried and underground piping and tanks are conducted in accordance with Table XI.M41-2 and the following. There are no inspection recommendations for titanium alloy, super austenitic, or nickel alloy materials; however, these materials are opportunistically inspected when exposed. Table XI.M41-2 inspection quantities are for a single unit plant. For two-unit sites, the inspection quantities (i.e., not the percentage of pipe length) are increased by 50 percent. For a three-unit site, the inspection quantities are doubled. For multi-unit sites, the inspections are distributed evenly among the units. Additional inspections, beyond those in Table XI.M41-2 may be appropriate if exceptions are taken to program element 2, “preventive actions,” or in response to plant-specific OE.

Inspections of buried and underground piping and tanks are conducted during each 10-year period, commencing 10 years prior to the subsequent period of extended operation. Piping inspections are typically conducted by visual examination of the external surfaces of pipe or coatings. Tank inspections are conducted externally by visual examination of the surfaces of the tank or coating or internally by volumetric methods. Opportunistic inspections are conducted for in-scope piping whenever they become accessible. Visual inspections are supplemented with surface and/or volumetric nondestructive testing if evidence of wall loss beyond minor surface scale is observed.

Table XI.M41-2. Inspection of Buried and Underground Piping and Tanks
Inspections of Buried Piping
Material	Preventive Action Categories		Inspection See Section 4.c. for Extent of Inspections
Stainless steel			1 inspection
Polymeric	Backfill is in accordance with preventive actions program element		1 inspection
	Backfill is not in accordance with preventive actions program element		The smaller of 1% of the length of pipe or 2 inspections
Cementitious			1 inspection
Steel	C		The smaller of 0.5% of the piping length or 1 inspection
	D		The smaller of 1% of the length of pipe or 2 inspections
	E		The smaller of 5% of the piping length or 3 inspections
	F		The smaller of 10% of the piping length or 6 inspections
Copper alloy	C		The smaller of 0.5% of the piping length or 1 inspection
	D		The smaller of 1% of the length of pipe or 2 inspections
	E		The smaller of 5% of the piping length or 3 inspections
	F		The smaller of 10% of the piping length or 6 inspections
Aluminum alloy	C		The smaller of 0.5% of the piping length or 1 inspection
	D		The smaller of 1% of the length of pipe or 2 inspections
	E		The smaller of 5% of the piping length or 3 inspections
	F		The smaller of 10% of the piping length or 6 inspections
Inspections of Buried Tanks and Underground Piping and Tanks
Material	Buried Tanks	Underground Piping	Underground Tanks
Stainless steel	All tanks	1 inspection	All tanks
Polymeric	All tanks	1 inspection	None
Cementitious	All tanks	1 inspection	None
Steel	All tanks	The smaller of 2% of the piping length or 2 inspections	All tanks
Copper alloy or Aluminum alloy	All tanks	The smaller of 1% of the length of piping or 1 inspection	All tanks
The Preventive Action Categories are used as follows: Category A no longer used. Category B no longer used. : Category C applies when: Cathodic protection was installed or refurbished 5 years prior to the end of the inspection period of interest; and Cathodic protection has operated at least 85% of the time either since 10 years prior to the subsequent period of extended operation or since installation/refurbishment, whichever is shorter. Time periods in which the cathodic protection system is off-line for testing do not have to be included in the total non-operating hours; and Cathodic protection has provided effective protection for buried piping as evidenced by meeting the acceptance criteria of Table XI.M41-3 of this AMP at least 80% of the time either since 10 years prior to the subsequent period of extended operation or since installation/refurbishment, whichever is shorter. As found results of annual surveys are to be used to determine locations within the plant’s population of buried pipe where cathodic protection acceptance criteria have, or have not, been met. Inspection criteria provided for Category D piping may be used for those portions of in-scope buried piping where it has been determined, in accordance with the “preventive actions” program element of this AMP, that external corrosion control is not required. Inspection criteria provided for Category E piping may be used for those portions of the population of buried piping where: An analysis, conducted in accordance with the “preventive actions” program element of this AMP, has determined that installation or operation of a cathodic protection system is impractical; or A cathodic protection system has been installed but all or portions of the piping covered by that system fail to meet any of the criteria of Category C piping above, provided: Coatings and backfill are provided in accordance with the “preventive actions” program element of this AMP; and Plant-specific OE is acceptable (i.e., no leaks in buried piping due to external corrosion, no significant coating degradation or metal loss in more than 10% of inspections conducted); and Soil has been determined to not be corrosive for the material type (e.g., AWWA C105, “Polyethylene Encasement for Ductile-Iron Pipe Systems,” Table A.1, “Soil-Test Evaluation”). In order to determine that the soil is not corrosive, the applicant: Obtains a minimum of three sets of soil samples in each soil environment (e.g., moisture content, soil composition) in the vicinity in which in-scope components are buried. Tests the soil for soil resistivity, corrosion accelerating bacteria, pH, moisture, chlorides, sulfates, and redox potential. Determines the potential soil corrosivity for each material type of buried in-scope piping. In addition to evaluating each individual parameter, the overall soil corrosivity is determined. Conducts soil testing once in each 10-year period starting 10 years prior to the subsequent period of extended operation. Inspection criteria provided for Category F piping is used for those portions of in-scope buried piping which cannot be classified as Category C, D, or E.

1. Transitioning to a Higher Number of Inspections: Plant-specific conditions can result in transitioning to a higher number of inspections than originally planned at the beginning of a 10-year interval. For example, degraded performance of the cathodic protection system could result in transitioning from Preventive Action Category C to Preventive Action Category E. Coating, backfill, or the condition of exposed piping that do not meet acceptance criteria could result in transitioning from Preventive Action Category E to Preventive Action Category F. If this transition occurs in the latter half of the current 10-year interval, the timing of the additional examinations is based on the severity of the degradation identified and is commensurate with the consequences of a leak or loss of function, but in all cases, the examinations are completed within 4 years after the end of the particular 10-year interval. These additional inspections conducted during the 4 years following the end of an inspection interval cannot also be credited towards the number of inspections stated in Table XI.M41-2 for the following 10-year interval.
2. Exceptions to Table XI.M41-2 inspection quantities:
   1. Where piping constructed of steel, copper alloy, or aluminum alloy has been coated with the same coating system and the backfill has the same requirements, the total inspections for this piping may be combined to satisfy the recommended inspection quantity. For example, for Preventive Action Category F, 10 percent of the total of the associated steel, copper alloy, or aluminum alloy is inspected; or six 10-foot segments of steel, copper alloy, or aluminum alloy piping are inspected.
   2. For buried piping or tanks, inspections may be reduced to one-half the number of inspections indicated in Table XI.M41-2 when performance of the indicated inspections necessitates excavation of piping or tanks that has been fully backfilled using controlled low strength material. The inspection quantity is rounded up (e.g., where three inspections are recommended in Table XI.M41-2, two inspections are conducted).
      
      When conducting inspections of buried components embedded in concrete backfill, the backfill may be excavated and the pipe or tank examined, or the soil around the backfill may be excavated and the cementitious material examined. The inspection includes excavation of the top surfaces and at least 50 percent of the side surface to visually inspect for cracks in the backfill that could admit groundwater to the external surfaces of the component. When conducting inspection of backfill based on the number of inspections designated for that material type, 10 linear feet of the backfill is exposed for each inspection.
   3. No inspections are necessary if all the piping or tanks constructed from a specific material type is fully backfilled using controlled low strength material for: (a) polymeric and cementitious materials; (b) steel and copper alloy materials when Preventive Action Category C is met; and (c) stainless steel materials.
   4. If all of the in-scope polymeric material is nonsafety-related, no more than one inspection need be conducted.
   5. Buried polymeric tanks are only inspected if backfill is not in accordance with the preventive actions.
   6. Stainless steel tanks are inspected when they are not coated and the underground environment is potentially exposed to in-leakage of groundwater or rain water.
   7. Steel, copper alloy, and aluminum alloy buried tanks are not inspected if the cathodic protection provided for the tank met the criteria for Preventive Action Category C.
3. Guidance related to the extent of inspections for piping is as follows:
   1. When the inspections are based on the number of inspections in lieu of percentage of piping length, 10 feet of piping is exposed for each inspection.
   2. When the percentage of inspections for a given material type results in an inspection quantity of less than 10 feet, then 10 feet of piping is inspected. If the entire run of piping of that material type is less than 10 feet in total length, then the entire run of piping is inspected.
4. Piping inspection location selection: Piping inspection locations are selected based on risk (i.e., susceptibility to degradation and consequences of failure). Characteristics such as coating type (i.e., material type), coating condition, cathodic protection efficacy, backfill characteristics, soil resistivity, pipe contents, and pipe function are considered. Opportunistic examinations of nonleaking pipes may be credited toward examinations if the location selection criteria are met. The use of guided wave ultrasonic examinations may not be substituted for the inspections listed in the table.
5. Alternatives to visual examination of piping are as follows:
   1. Aging effects associated with fire mains may be managed by either: (a) a flow test as described in Section 7.3 of NFPA 25 at a frequency of at least one test in each 1-year period; (b) monitoring the activity of the jockey pump (e.g., pump starts, run time) on an interval not to exceed 1 month; or (c) an annual system leak rate test. If the aging effects are not managed by one of these alternatives, and the extent of inspections is not based on the percentage of piping for that material type, then two additional inspections are added to the inspection quantity for that material type.
   2. At least 25 percent of the in-scope piping constructed from the material under consideration is pressure tested on an interval not to exceed 5 years. The piping is pressurized to 110 percent of the design pressure of any component within the boundary (not to exceed the maximum allowable test pressure of any nonisolated components) with test pressure being held for a continuous eight hour interval.
   3. At least 25 percent of the in-scope piping constructed from the material under consideration is internally inspected by a method capable of precisely determining pipe wall thickness. The inspection method has been determined to be capable of detecting both general and pitting corrosion on the external surface of the piping and is qualified by the applicant to identify loss of material that does not meet acceptance criteria. Ultrasonic examinations, in general, satisfy this criterion. As of the effective date of this document, guided wave ultrasonic examinations do not meet the intent of this paragraph. If internal inspections are to be conducted in lieu of direct visual examination, they are conducted at an interval not to exceed 10 years.
6. Examinations are conducted from the external surface of the tank using visual techniques or from the internal surface of the tank using volumetric techniques. A minimum of 25 percent coverage is obtained. This area includes at least some of both the top and bottom of the tank. If the tank is inspected internally by volumetric methods, the method is: capable of determining tank wall thickness, determined to be capable of detecting both general and pitting corrosion, and qualified by the applicant to identify loss of material that does not meet acceptance criteria. Double wall tanks may be examined by monitoring the annular space for leakage.

5. Monitoring and Trending: For piping and tanks protected by cathodic protection systems, potential difference and current measurements are trended to identify changes in the effectiveness of the systems and/or coatings. If aging of fire mains is managed through monitoring jockey pump activity (or a similar parameter), the jockey pump activity (or similar parameter) is trended to identify changes in pump activity that may be the result of increased leakage from buried fire main piping. Likewise, if leak rate testing is conducted, leak rates are trended. Where wall thickness measurements are conducted, the results are trended when follow up examinations are conducted.

Where practical, all other degradation (e.g., coating condition, cementitious piping 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: The acceptance criteria associated with this AMP are:

1. For coated piping or tanks, there is either no evidence of coating degradation, or the type and extent of coating degradation is evaluated as insignificant by an individual: (a) possessing a NACE Coating Inspector Program Level 2 or 3 inspector qualification; (b) who has completed the Electric Power Research Institute Comprehensive Coatings Course and completed the EPRI Buried Pipe Condition Assessment and Repair Training Computer Based Training Course; or (c) a coatings specialist qualified in accordance with an ASTM standard endorsed in Regulatory Guide 1.54, Revision 2, “Service Level I, II, and III Protective Coatings Applied to Nuclear Power Plants.”]
2. Cracking is absent in rigid polymeric components. Blisters, gouges, or wear of nonmetallic piping is evaluated.
3. The measured wall thickness projected to the end of the subsequent period of extended operation meets minimum wall thickness requirements.
4. Indications of cracking in metallic pipe are managed in accordance with the “corrective actions” program element.
5. Cementitious piping may exhibit minor cracking and loss of material provided there is no evidence of leakage exposed or rust staining from rebar or reinforcing “hoop” bands.
6. Backfill is acceptable if the inspections do not reveal evidence that the backfill caused damage to the component’s coatings or the surface of the component (if not coated).
7. Flow test results for fire mains are in accordance with NFPA 25, Section 7.3.
8. For pressure tests, the test acceptance criteria are that there are no visible indications of leakage, and no drop in pressure within the isolated portion of the piping that is not accounted for by a temperature change in the test media or by quantified leakage across test boundary valves.
9. Changes in jockey pump activity (or similar parameter) that cannot be attributed to causes other than leakage from buried piping, are not occurring.
10. When fire water system leak rate testing is conducted, leak rates are within acceptance limits of plant-specific documents.
11. Cracks in cementitious backfill that could admit groundwater to the surface of the component are not acceptable.
12. Criteria for pipe-to-soil potential when using a saturated CSE is as stated in Table XI.M41-3, or acceptable alternatives as stated below.

    Table XI.M41-3. Cathodic Protection Acceptance Criteria
    Material	Criteria1,2
    Steel	−850 mV relative to a CSE, instant off
    Copper alloy	100 mV minimum polarization
    Aluminum alloy	100 mV minimum polarization
    1Plants with sacrificial anode systems state the test method and acceptance criteria and the basis for the method and criteria in the application. 2For steel piping, when: (a) active MIC has been identified or is probable; (b) temperatures greater than 60 °C (140 °F); or (c) in weak acid environments, a polarized potential of -950 mV or more negative is recommended.

13. Alternatives to the -850 mV criterion for steel piping in Table XI.M41-3 are as follows.
    1. 100 mV minimum polarization
    2. -750 mV relative to a CSE, instant off where soil resistivity is greater than 10,000 ohm-cm to less than 100,000 ohm-cm
    3. -650 mV relative to a CSE, instant off where soil resistivity is greater than 100,000 ohm-cm
    4. Verify less than 1 mpy loss of material. Loss of material rates in excess of 1 mpy may be acceptable if an engineering evaluation demonstrates that the corrosion rate would not result in a loss of intended function prior to the end of the subsequent period of extended operation. The engineering evaluation is cited and summarized in the SLRA.

When using the 100 mV, -750 mV, or -650 mV polarization criteria as an alternative to the -850 mV criterion for steel piping, means to verify the effectiveness of the protection of the most anodic metal is incorporated into the program. One acceptable means to verify the effectiveness of the cathodic protection system, or to demonstrate that the loss of material rate is acceptable, is to use installed electrical resistance corrosion rate probes. The external loss of material rate is verified:

• Every year when verifying the effectiveness of the cathodic protection system by measuring the loss of material rate.
• Every 2 years when using the 100 mV minimum polarization.
• Every 5 years when using the -750 or -650 criteria associated with higher resistivity soils. The soil resistivity is verified every 5 years.

As an alternative to verifying the effectiveness of the cathodic protection system every 5 years, soil resistivity testing is conducted annually during a period of time when the soil resistivity would be expected to be at its lowest value (e.g., maximum rainfall periods). Upon completion of 10 annual consecutive soil samples, soil resistivity testing can be extended to every 5 years if the results of the soil sample tests consistently verified that the resistivity did not fall outside of the range being credited (e.g., for the -750 mV relative to a CSE, instant off criterion, all soil resistivity values were greater than 10,000 ohm-cm).

When electrical resistance corrosion rate probes will be used, the application identifies:

• The qualifications of the individuals that will determine the installation locations of the probes and the methods of use (e.g., NACE CP4, “Cathodic Protection Specialist”).
• How the impact of significant site features (e.g., large cathodic protection current collectors, shielding due to large objects located in the vicinity of the protected piping) and local soil conditions will be factored into placement of the probes and use of probe data.

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 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 corrective actions element of this AMP for both safety-related and nonsafety-related structures and components (SCs) within the scope of this program.

1. Where damage to the coating has been evaluated as significant and the damage was caused by nonconforming backfill, an extent of condition evaluation is conducted to determine the extent of degraded backfill in the vicinity of the observed damage.
2. If coated or uncoated metallic piping or tanks show evidence of corrosion, the remaining wall thickness in the affected area is determined to ensure that the minimum wall thickness is maintained. This may include different values for large area minimum wall thickness and local area wall thickness. If the wall thickness extrapolated to the end of the subsequent period of extended operation meets minimum wall thickness requirements, recommendations for expansion of sample size below do not apply.
3. Where the coatings, backfill, or the condition of exposed piping does not meet acceptance criteria, the degraded condition is repaired or the affected component is replaced. In addition, where the depth or extent of degradation of the base metal could have resulted in a loss of pressure boundary function when the loss of material is extrapolated to the end of the subsequent period of extended operation, an expansion of sample size is conducted. The number of inspections within the affected piping categories are doubled or increased by five, whichever is smaller. If the acceptance criteria are not met in any of the expanded samples, an analysis is conducted to determine the extent of condition and extent of cause. The number of follow-on inspections is determined based on the extent of condition and extent of cause.
   
   The timing of the additional examinations is based on the severity of the degradation identified and is commensurate with the consequences of a leak or loss of function. However, in all cases, the expanded sample inspection is completed within the 10-year interval in which the original inspection was conducted or, if identified in the latter half of the current 10-year interval, within 4 years after the end of the 10-year interval. These additional inspections conducted during the 4 years following the end of an inspection interval cannot also be credited towards the number of inspections in Table XI.M41-2 for the following 10-year interval. The number of inspections may be limited by the extent of piping or tanks subject to the observed degradation mechanism.
   
   The expansion of sample inspections may be halted in a piping system or portion of system that will be replaced within the 10-year interval in which the inspections were conducted or, if identified in the latter half of the current 10-year interval, within 4 years after the end of the 10-year interval.
4. Unacceptable cathodic protection survey results are entered into the plant corrective action program.
5. Sources of leakage detected during pressure tests are identified and corrected.
6. When using the option of monitoring the activity of a jockey pump instead of inspecting buried fire water system piping, a flow test or system leak rate test is conducted by the end of the next refueling outage or as directed by the current licensing basis, whichever is shorter, when unexplained changes in jockey pump activity (or equivalent equipment or parameter) are observed.
7. Indications of cracking are evaluated in accordance with applicable codes and plant-specific design criteria.

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: Operating experience shows that buried and underground piping and tanks are subject to corrosion. Corrosion of buried oil, gas, and hazardous materials pipelines have been adequately managed through a combination of inspections and mitigative techniques, such as those prescribed in NACE SP0169-2007 and NACE RP0285-2002. Given the differences in piping and tank configurations between transmission pipelines and those in nuclear facilities, it is necessary for the applicant to evaluate both plant-specific and nuclear industry OE and to modify its AMP accordingly. The following examples of industry experience may be of significance to an applicant’s program:

1. In August 2009, a leak was discovered in a portion of buried aluminum pipe where it passed through a concrete wall. The piping is in the condensate transfer system. The failure was caused by vibration of the pipe within its steel support system. This vibration led to coating failure and eventual galvanic corrosion between the aluminum pipe and the steel supports. [Agencywide Documents Access and Management System (ADAMS) Accession No. ML093160004].
2. In June 2009, an active leak was discovered in buried piping associated with the condensate storage tank. The leak was discovered because elevated levels of tritium were detected. The cause of the through-wall leaks was determined to be the degradation of the protective moisture barrier wrap that allowed moisture to come in contact with the piping resulting in external corrosion. (ADAMS Accession No. ML093160004).
3. In April 2010, while performing inspections as part of its buried pipe program, a licensee discovered that major portions of their auxiliary feedwater piping were substantially degraded. The licensee’s cause determination attributes the cause of the corrosion to the failure to properly coat the piping “as specified” during original construction. The affected piping was replaced during the next refueling outage. (ADAMS Accession No. ML103000405).
4. In November 2013, minor weepage was noted in a 10-inch service water supply line to the emergency diesel generators while performing a modification to a main transformer moat. Coating degradation was noted at approximately 10 locations along the exposed piping. The leaking and unacceptable portions of the degraded pipe were clamped and recoated until a permanent replacement could be implemented. (ADAMS Accession No. ML13329A422).

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.

ASTM. ASTM D 448-08, “Classification for Sizes of Aggregate for Road and Bridge Construction.” West Conshohocken, Pennsylvania: ASTM International. 2008.

AWWA. C105, “Polyethylene Encasement for Ductile-Iron Pipe Systems.” Denver, Colorado: American Water Works Association. 2010.

EPRI. EPRI 1021175, “Recommendations for an Effective Program to Control the Degradation of Buried and Underground Piping and Tanks,” (1016456 Revision 1(Archived)). Palo Alto, California: Electric Power Research Institute. December 23, 2010.

ISO. ISO 15589-1, “Petroleum and Natural Gas Industries–Cathodic Protection of Pipeline Transportation Systems–Part 1: On Land Pipelines.” Vernier, Geneva, Switzerland: International Organization for Standardization. November 2003.

NACE. Recommended Practice RP0100-2004, “Standard Recommended Practice, Cathodic Protection of Prestressed Concrete Cylinder Pipelines.” Houston, Texas: NACE International. 2004.

_____. Recommended Practice RP0285-2002, “Corrosion Control of Underground Storage Tank Systems by Cathodic Protection.” Houston, Texas: NACE International. April 2002.

_____. Standard Practice SP0169-2007, “Control of External Corrosion on Underground or Submerged Metallic Piping Systems.” Houston, Texas: NACE International. 2007.

NFPA. NFPA 24, “Standard for the Installation of Private Fire Service Mains and Their Appurtenances.” Quincy, Massachusetts: National Fire Protection Association. 2010.

_____. NFPA 25, “Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems, 2011 Edition.” Quincy, Massachusetts: National Fire Protection Association. 2011.

US NRC. Regulatory Guide 1.54, “Service Level I, II, and III Protective Coatings Applied to Nuclear Power Plants.” Revision 2. Washington, DC: U.S. Nuclear Regulatory Commission. October 2010.

Aging Management Program

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.

Operating Experience

Microbiologically Influenced Corrosion - A degradation mechanism of corrosion influenced by microorganisms.

Quality Assurance

Agency wide Documents Access and Management System - The official recordkeeping system, through which the U.S. Nuclear Regulatory Commission (US NRC) provides access to the "libraries" or collections of publicly available documents

Electric Power Research Institute

United States of America

Nuclear Regulatory Commission - The US federal government agency that regulates nuclear power plants