ML11349A085
ML11349A085 | |
Person / Time | |
---|---|
Site: | Indian Point |
Issue date: | 12/31/2010 |
From: | Office of Nuclear Reactor Regulation |
To: | Atomic Safety and Licensing Board Panel |
SECY RAS | |
References | |
RAS 21545, 50-247-LR, 50-286-LR, ASLBP 07-858-03-LR-BD01 | |
Download: ML11349A085 (189) | |
Text
NYS00147D Submitted: December 15, 2011 BWRVIP-59-A (EPRI 1014874), BWR Vessel and Internals Project, Evaluation of Crack Growth in BWR Nickel-Base Austenitic Alloys in RPV Internals, Final Safety Evaluation Report by the Office of Nuclear Reactor Regulation, May 2007.
BWRVIP-60-A (EPRI 1008871), BWR Vessel and Internals Project, Evaluation of Stress Corrosion Crack Growth in Low Alloy Steel Vessel Materials in the BWR Environment, Final Safety Evaluation Report by the Office of Nuclear Reactor Regulation, June 2003.
BWRVIP-190 (EPRI 1016579), BWR Vessel and Internals Project, BWR Water Chemistry Guidelines-2008 Revision, Final Safety Evaluation Report by the Office of Nuclear Reactor Regulation, October 2008.
NUREG-1801, Rev. 2 XI M8-4 December 201 0 OAG10001390_00568
XI.M9 BWR VESSEL INTERNALS Program Description The program includes inspection and flaw evaluations in conformance with the guidelines of applicable and staff-approved boiling water reactor vessel and internals project (BWRVIP) documents to provide reasonable assurance of the long-term integrity and safe operation of boiling water reactor (BWR) vessel internal components.
The BWRVIP documents provide generic guidelines intended to present the applicable inspection recommendations to assure safety function integrity of the subject safety-related reactor pressure vessel internal components. The guidelines provide information on component description and function; evaluate susceptible locations and safety consequences of failure; provide recommendations for methods, extent, and frequency of inspection; discuss acceptable methods for evaluating the structural integrity significance of flaws detected during these examinations; and recommend repair and replacement procedures.
In addition, this program provides screening criteria to determine the susceptibility of cast austenitic stainless steels (CASS) components to thermal aging on the basis of casting method, molybdenum content, and percent ferrite, in accordance with the criteria set forth in the May 19, 2000 letter from Christopher Grimes, Nuclear Regulatory Commission (NRC), to Mr. Douglas Walters, Nuclear Energy Institute (NEI). The susceptibility to thermal aging embrittlement of CASS components is determined in terms of casting method, molybdenum content, and ferrite content. For low-molybdenum content steels (SA-351 Grades CF3, CF3A, CFS, CFSA, or other steels with :::;0.5 wt. % molybdenum), only static-cast steels with >20% ferrite are potentially susceptible to thermal embrittlement. Static-cast low-molybdenum steels with >20% ferrite and all centrifugal-cast low-molybdenum steels are not susceptible. For high-molybdenum content steels (SA-351 Grades CF3M, CF3MA, CFSM or other steels with 2.0 to 3.0 wt.% molybdenum),
static-cast steels with >14% ferrite and centrifugal-cast steels with >20% ferrite are potentially susceptible to thermal embrittlement. Static-cast high-molybdenum steels with :::;14% ferrite and centrifugal-cast high-molybdenum steels with :::;20% ferrite are not susceptible. In the susceptibility screening method, ferrite content is calculated by using the Hull's equivalent factors (described in NUREG/CR-4513, Rev. 1) or a staff approved method for calculating delta ferrite in CASS materials.
The screening criteria are applicable to all cast stainless steel primary pressure boundary and reactor vessel internal components with service conditions above 250°C (4S2°F). The screening criteria for susceptibility to thermal aging embrittlement are not applicable to niobium-containing steels; such steels require evaluation on a case-by-case basis. For "potentially susceptible" components, the program considers loss of fracture toughness due to neutron embrittlement or thermal aging embrittlement.
This AMP addresses aging degradation of X-750 alloy-, and precipitation-hardened (PH) martensitic stainless steel (e.g., 15-5 and 17-4 PH steel) materials and martensitic stainless steel (e.g., 403, 410, 431 steel) that are used in BWR vessel internal components. When exposed to a BWR reactor temperature of 550°F, these materials can experience neutron embrittlement and a decrease in fracture toughness. PH-martensitic stainless steels and martensitic stainless steels are also susceptible to thermal embrittlement. Effects of thermal and neutron embrittlement can cause failure of these materials in vessel internal components. In addition, X-750 alloy in a BWR environment is susceptible to intergranular stress corrosion cracking (lGSCC).
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Evaluation and Technical Basis
- 1. Scope of Program: The program is focused on managing the effects of cracking due to stress corrosion cracking (SCC), IGSCC, or irradiation-assisted stress corrosion cracking (lASCC), cracking due to fatigue and loss of material due to wear. This program also includes loss of toughness due to neutron and thermal embrittlement. The program applies to wrought and cast reactor vessel internal components. The program contains in-service inspection (lSI) to monitor the effects of cracking on the intended function of the components, uses NRC-approved BWRVIP reports as the basis for inspection, evaluation, repair and/or replacement, as needed, and evaluates the susceptibility of CASS, X-7S0 alloy, precipitation-hardened (PH) martensitic stainless steel (e.g., 1S-S and 17-4 PH steel),
and martensitic stainless steel (e.g., 403, 410, 431 steel) components to neutron and/or thermal embrittlement.
The scope of the program includes the following BWR reactor vessel (RV) and RV internal components as subject to the following NRC-approved applicable BWRVIP guidelines:
Core shroud: BWRVIP-76-A provides guidelines for inspection and evaluation; BWRVIP-02-A, Rev. 2, provides guidelines for repair design criteria.
Core plate: BWRVIP-2S provides guidelines for inspection and evaluation; BWRVIP-SO-A provides guidelines for repair design criteria.
Core spray: BWRVIP-18-A provides guidelines for inspection and evaluation; BWRVIP-16-A and 19A provides guidelines for replacement and repair design criteria, respectively.
Shroud support: BWRVIP-38 provides guidelines for inspection and evaluation; BWRVIP-S2-A provides guidelines for repair design criteria.
Jet pump assembly: BWRVIP-41 provides guidelines for inspection and evaluation; BWRVIP-S1-A provides guidelines for repair design criteria.
Low-pressure coolant injection (LPCI) coupling: BWRVIP-42-A provides guidelines for inspection and evaluation; BWRVIP-S6-A provides guidelines for repair design criteria.
Top guide: BWRVIP-26-A and BWRVIP-183 provide guidelines for inspection and evaluation; BWRVIP-SO-A provides guidelines for repair design criteria. Inspect five percent (S%) of the top guide locations using enhanced visual inspection technique, EVT-1 within six years after entering the period of extended operation. An additional S% of the top guide locations will be inspected within twelve years after entering the period of extended operation.
Reinspection Criteria:
BWR/2-S - Inspect 10% of the grid beam cells containing control rod drives/blades every twelve years with at least S% to be performed within six years.
BWR/6 - Inspect the rim areas containing the weld and heat affected zone (HAZ) from the top surface of the top guide and two cells in the same plane/axis as the weld every six years.
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The top guide inspection locations are those that have high neutron fluences exceeding the IASCC threshold. The extent of the examination and its frequency will be based on a ten percent sample of the total population, which includes all grid beam and beam-to-beam crevice slots.
Control rod drive (CRD) housing: BWRVIP-47-A provides guidelines for inspection and evaluation; BWRVIP-58-A provides guidelines for repair design criteria.
Lower plenum components: BWRVIP-47-A provides guidelines for inspection and evaluation; BWRVIP-57-A provides guidelines for repair design criteria for instrument penetrations.
Steam Dryer. BWRVIP-139 provides guidelines for inspection and evaluation for the steam dryer components.
Although BWRVI P repair design criteria provide criteria for repairs, aging management strategies for repairs are provided by the repair designer, not the BWRVIP.
- 2. Preventive Actions: The BWR Vessel Internals Program is a condition monitoring program and has no preventive actions. Maintaining high water purity reduces susceptibility to SCC or IGSCC. Reactor coolant water chemistry is monitored and maintained in accordance with the Water Chemistry Program. The program description, evaluation and technical basis of water chemistry are presented in GALL AMP XI.M2, "Water Chemistry." In addition, for core shroud repairs or other IGSCC repairs, the program maintains operating tensile stresses below a threshold limit that precludes IGSCC of X-750 material.
- 3. Parameters Monitored/Inspected: The program monitors the effects of cracking on the intended function of the component by detection and sizing of cracks by inspection in accordance with the guidelines of applicable and approved BWRVIP documents and the requirements of the American Society of Mechanical Engineers (ASME) Code,Section XI, Table IWB 2500-1 (2004 edition 9 ).
Loss of fracture toughness due to neutron embrittlement in CASS materials can occur with a neutron fluence greater than 1x1 0 17 n/cm 2 (E>1 MeV). Loss fracture toughness of CASS material due to thermal embrittlement is dependent on the material's casting method, molybdenum content, and ferrite content. The program does not directly monitor for loss of fracture toughness that is induced by thermal aging or neutron irradiation embrittlement. The impact of loss of fracture toughness on component integrity is indirectly managed by using visual or volumetric examination techniques to monitor for cracking in the components.
Neutron embrittlement of X-750 alloys, PH-martensitic stainless steels, and martensitic stainless steels cannot be identified by typical in-service inspection activities. However, by performing visual or other inspections, applicants can identify cracks that could lead to failure of a potentially embrittled component prior to component failure. Applicants can thus indirectly manage the effects of embrittlement in the PH steels, martensitic stainless steels, and X-750 components by identifying aging degradation (i.e., cracks), implementing early corrective actions, and monitoring and trending age-related degradation.
9 Refer to the GALL Report, Chapter I, for applicability of other editions of the ASME Code,Section XI.
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- 4. Detection of Aging Effects: The extent and schedule of the inspection and test techniques prescribed by the applicable and NRC-approved BWRVIP guidelines are designed to maintain structural integrity and ensure that aging effects will be discovered and repaired before the loss of intended function of BWR vessel internals. Inspection can reveal cracking.
Vessel internal components are inspected in accordance with the requirements of ASME Section XI, Subsection IWB, Examination Category B-N-2. The ASME Section XI inspection specifies visual VT-1 examination to detect discontinuities and imperfections, such as cracks, corrosion, wear, or erosion, on the surfaces of components. This inspection also specifies visual VT-3 examination to determine the general mechanical and structural condition of the component supports by (a) verifying parameters, such as clearances, settings, and physical displacements, and (b) detecting discontinuities and imperfections, such as loss of integrity at bolted or welded connections, loose or missing parts, debris, corrosion, wear, or erosion. BWRVIP program requirements provide for inspection of BWR reactor internals to manage loss of material and cracking using appropriate examination techniques such as visual examinations (e.g., EVT-1, VT-1) and volumetric examinations (e.g., UT).
The applicable and NRC-approved BWRVIP guidelines recommend more stringent inspections, such as EVT-1 examinations or ultrasonic methods of volumetric inspection, for certain selected components and locations. The nondestructive examination (NDE) techniques appropriate for inspection of BWR vessel internals, including the uncertainties inherent in delivering and executing NDE techniques in a BWR, are included in BWRVIP-03.
Thermal and/or neutron embrittlement in susceptible CASS, PH-martensitic steels, martensitic stainless steels, and X-750 components are indirectly managed by performing periodic visual inspections capable of detecting cracks in the component. The 10-year lSI program during the renewal period may include a supplemental inspection covering portions of the susceptible components determined to be limiting from the standpoint of thermal aging susceptibility, neutron fluence, and cracking susceptibility (i.e., applied stress, operating temperature, and environmental conditions). The inspection technique is capable of detecting the critical flaw size with adequate margin. The critical flaw size is determined based on the service loading condition and service-degraded material properties. One example of a supplemental examination is VT-1 examination of ASME Code,Section XI, IWA-2210. The initial inspection is performed either prior to or within 5 years after entering the period of extended operation. If cracking is detected after the initial inspection, the frequency of re-inspection should be justified by the applicant based on fracture toughness properties appropriate for the condition of the component. The sample size is 100% of the accessible component population, excluding components that may be in compression during normal operations.
- 5. Monitoring and Trending: Inspections are scheduled in accordance with the applicable and approved BWRVI P guidelines provide timely detection of cracks. Each BWRVI P guideline recommends baseline inspections that are used as part of data collection towards trending. The BWRVIP guidelines provide recommendations for expanding the sample scope and re-inspecting the components if flaws are detected. Any indication detected is evaluated in accordance with ASME Code,Section XI or the applicable BWRVIP guidelines.
BWRVIP-14-A, BWRVIP-59-A, BWRVIP-60-A, BWRVIP-80NP-A and BWRVIP-99-A documents provide additional guidelines for evaluation of crack growth in stainless steels (SSs), nickel alloys, and low-alloy steels, respectively.
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Inspections scheduled in accordance with ASME Code,Section XI, IWB-2400 and reliable examination methods provide timely detection of cracks. The fracture toughness of PH-martensitic steels, martensitic stainless steels, and X-750 alloys susceptible to thermal and/or neutron embrittlement need to be assessed on a case-by-case basis.
- 6. Acceptance Criteria: Acceptance criteria are given in the applicable BWRVI P documents or ASME Code,Section XI. Flaws detected in CASS components are evaluated in accordance with the applicable procedures of ASME Code,Section XI, IWB-3500. Flaw tolerance evaluation for components with ferrite content up to 25% is performed according to the principles associated with ASME Code,Section XI, IWB-3640 procedures for SAWs, disregarding the ASME Code restriction of 20% ferrite. Extensive research data indicate that the lower-bound fracture toughness of thermally aged CASS materials with up to 25% ferrite is similar to that for SAWs with up to 20% ferrite (Lee et aI., 1997). Flaw evaluation for CASS components with >25% ferrite is performed on a case-by-case basis by using fracture toughness data provided by the applicant. A fracture toughness value of 255 kJ/m 2 (1,450 in.-lb/in.2) at a crack depth of 2.5 mm (0.1 in.) is used to differentiate between CASS materials that are susceptible to thermal aging embrittlement and those that are not.
Extensive research data indicate that for non-susceptible CASS materials, the saturated lower-bound fracture toughness is greater than 255 kJ/m 2(NUREG/CR-4513, Rev. 1).
Acceptance criteria for the assessment of PH-martensitic steels, martensitic stainless steels, and X-750 alloys susceptible to thermal aging and/or neutron embrittlement are assessed on a case-by-case basis.
- 7. Corrective Actions: Repair and replacement procedures are equivalent to those requirements in ASME Code Section XI. Repair and replacement is performed in conformance with the applicable and NRC-approved BWRVIP guidelines listed above. For top guides where cracking is observed, sample size and inspection frequencies are increased. As discussed in the Appendix for GALL, the staff finds that licensee implementation of the corrective action guidelines in the staff-approved BWRVI P reports will provide an acceptable level of quality accordance with 10 CFR Part 50, Appendix B.
- 8. Confirmation Process: Site quality assurance procedures, review and approval processes, and administrative controls are implemented in accordance with the requirements of 10 CFR Part 50, Appendix B. As discussed in the Appendix for GALL, the staff finds that licensee implementation of the guidelines in the staff-approved BWRVIP reports will provide an acceptable level of quality for inspection and flaw evaluation of the safety-related components addressed in accordance with the 10 CFR Part 50, Appendix B, confirmation process and administrative controls.
- 9. Administrative Controls: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B acceptable to address the administrative controls.
- 10. Operating Experience: There is documentation of cracking in both the circumferential and axial core shroud welds, and in shroud supports. Extensive cracking of circumferential core shroud welds has been documented in NRC Generic Letter 94-03 and extensive cracking in vertical core shroud welds has been documented in NRC Information Notice 97-17. It has affected shrouds fabricated from Type 304 and Type 304L SS, which is generally considered to be more resistant to SCC. Weld regions are most susceptible to SCC, although it is not clear whether this is due to sensitization and/or impurities associated with December 201 0 XI M9-S NUREG-1801, Rev. 2 OAG10001390_00573
the welds or the high residual stresses in the weld regions. This experience is reviewed in NRC GL 94-03 and NUREG-1544; some experiences with visual inspections are discussed in NRC IN 94-42.
Both circumferential (NRC IN 88-03) and radial cracking (NRC IN 92-57) have been observed in the shroud support access hole covers that are made from Alloy 600. Instances of cracking in core spray spargers have been reviewed in NRC Bulletin 80-13, and cracking in core spray pipe has been reviewed in BWRVIP-18.
Cracking of the core plate has not been reported, but the creviced regions beneath the plate are difficult to inspect. BWRVIP-06R1-A and BWRVIP-25 address the safety significance and inspection requirements for the core plate assembly. Only inspection of core plate bolts (for plants without retaining wedges) or inspection of the retaining wedges is required. NRC IN 95-17 discusses cracking in top guides of United States and overseas BWRs. Related experience in other components is reviewed in NRC GL 94-03 and NUREG-1544. Cracking has also been observed in the top guide of a Swedish BWR.
Instances of cracking have occurred in the jet pump assembly (NRC Bulletin 80-07), hold-down beam (NRC IN 93-101), and jet pump riser pipe elbows (NRC IN 97-02).
Cracking of dry tubes has been observed at 14 or more BWRs. The cracking is intergranular and has been observed in dry tubes without apparent sensitization, suggesting that IASCC may also playa role in the cracking.
Two CRDM lead screw male couplings were fractured in a pressurized-water reactor (PWR),
designed by Babcock and Wilcox (B&W), at Oconee Nuclear Station (ONS), Unit 3. The fracture was due to thermal embrittlement of 17-4 PH material (NRC IN 2007-02). While this occurred at a PWR, it also needs to be considered for BWRs.
IGSCC in the X-750 materials of a tie rod coupling and jet pump hold-down beam was observed in a domestic plant.
The program guidelines outlined in applicable and approved BWRVIP documents are based on an evaluation of available information, including BWR inspection data and information on the elements that cause SCC, IGSCC, or IASCC, to determine which components may be susceptible to cracking. Implementation of the program provides reasonable assurance that cracking will be adequately managed so the intended functions of the vessel internal components will be maintained consistent with the current licensing basis (CLB) for the period of extended operation.
References 10 CFR Part 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
10 CFR 50.55a, Codes and Standards, Office of the Federal Register, National Archives and Records Administration, 2009.
ASME Section XI, Rules for In service Inspection of Nuclear Power Plant Components, The ASME Boiler and Pressure Vessel Code, 2004 edition as approved in 10 CFR 50.55a, The American Society of Mechanical Engineers, New York, NY.
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BWRVIP-02-A (EPRI 1012837), BWR Vessel and Internals Project, BWR Core Shroud Repair Design Criteria, Final Safety Evaluation Report by the Office of Nuclear Reactor Regulation, October 2005.
BWRVIP-03 (EPRI 105696 R1, March 30,1999), BWR Vessel and Internals Project, Reactor Pressure Vessel and Internals Examination Guidelines, Final Safety Evaluation Report by the Office of Nuclear Reactor Regulation, July 15, 1999.
BWRVIP-14-A (EPRI1016569), BWR Vessel and Internals Project, Evaluation of Crack Growth in BWR Stainless Steel RPV Internals, Final Safety Evaluation Report by the Office of Nuclear Reactor Regulation, September 2008.
BWRVIP-16-A (EPRI 1012113), BWR Vessel and Internals Project, Internal Core Spray Piping and Sparger Replacement Design Criteria, Final Safety Evaluation Report by the Office of Nuclear Reactor Regulation, September 2005.
BWRVIP-18-A (EPRI 1011469), BWR Vessel and Internals Project, BWR Core Spray Internals Inspection and Flaw Evaluation Guidelines, Final Safety Evaluation Report by the Office of Nuclear Reactor Regulation, February 2005.
BWRVIP-19-A (EPRI 1012114), BWR Vessel and Internals Project, Internal Core Spray Piping and Sparger Repair Design Criteria, Final Safety Evaluation Report by the Office of Nuclear Reactor Regulation, September 2005.
BWRVIP-25 (EPRI 107284), BWR Vessel and Internals Project, BWR Core Plate Inspection and Flaw Evaluation Guidelines, Dec. 1996, Final License Renewal Safety Evaluation Report by the Office of Nuclear Reactor Regulation for BWRVIP-25 for Compliance with the License Renewal Rule (10 CFR Part 54), December 7,2000.
BWRVIP-26-A (EPRI 1009946), BWR Vessel and Internals Project, BWR Top Guide Inspection and Flaw Evaluation Guidelines, Final Safety Evaluation Report by the Office of Nuclear Reactor Regulation, November 2004.
BWRVIP-38 (EPRI 108823), BWR Vessel and Internals Project, BWR Shroud Support Inspection and Flaw Evaluation Guidelines, September 1997, Final License Renewal Safety Evaluation Report by the Office of Nuclear Reactor Regulation for BWRVIP-38 for Compliance with the License Renewal Rule (10 CFR Part 54), March 1, 2001.
BWRVIP-41 (EPRI 108728), BWR Vessel and Internals Project, BWR Jet Pump Assembly Inspection and Flaw Evaluation Guidelines, October 1997, Final License Renewal Safety Evaluation Report by the Office of Nuclear Reactor Regulation for BWRVIP-41 for Compliance with the License Renewal Rule (10 CFR Part 54), June 15, 2001.
BWRVIP-42-A (EPRI 1011470), BWR Vessel and Internals Project, BWR LPCI Coupling Inspection and Flaw Evaluation Guidelines, Final Safety Evaluation Report by the Office of Nuclear Reactor Regulation, February 2005.
BWRVIP-44-A (EPRI1014352), BWR Vessel and Internals Project, Underwater Weld Repair of Nickel Alloy Reactor Vessel Internals, Final Safety Evaluation Report by the Office of Nuclear Reactor Regulation, August 2006.
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BWRVIP-45 (EPRI 108707), BWR Vessel and Internals Project, Weldability of Irradiated LWR Structural Components, Final Safety Evaluation Report by the Office of Nuclear Reactor Regulation, June 14,2000.
BWRVI P-47 -A (EPRI 1009947), BWR Vessel and Internals Project, BWR Lower Plenum Inspection and Flaw Evaluation Guidelines, Final Safety Evaluation Report by the Office of Nuclear Reactor Regulation, November 2004.
BWRVIP-50-A (EPRI 1012110), BWR Vessel and Internals Project, Top Guide/Core Plate Repair Design Criteria, Final Safety Evaluation Report by the Office of Nuclear Reactor Regulation, September 2005.
BWRVIP-51-A (EPRI 1012116), BWR Vessel and Internals Project, Jet Pump Repair Design Criteria, Final Safety Evaluation Report by the Office of Nuclear Reactor Regulation, September 2005.
BWRVIP-52-A (EPRI 1012119), BWR Vessel and Internals Project, Shroud Support and Vessel Bracket Repair Design Criteria, Final Safety Evaluation Report by the Office of Nuclear Reactor Regulation, September 2005.
BWRVIP-56-A (EPRI 1012118), BWR Vessel and Internals Project, LPCI Coupling Repair Design Criteria, Final Safety Evaluation Report by the Office of Nuclear Reactor Regulation, September 2005.
BWRVI P-57 -A (EPRI 1012111), BWR Vessel and Internals Project, Instrument Penetration Repair Design Criteria, Final Safety Evaluation Report by the Office of Nuclear Reactor Regulation, September 2005.
BWRVIP-58-A (EPRI 1012618), BWR Vessel and Internals Project, CRD Internal Access Weld Repair, Final Safety Evaluation Report by the Office of Nuclear Reactor Regulation, October 2005.
BWRVIP-59-A (EPRI 1014874), BWR Vessel and Internals Project, Evaluation of Crack Growth in BWR Nickel-Base Austenitic Alloys in RPV Internals, Final Safety Evaluation Report by the Office of Nuclear Reactor Regulation, May 2007.
BWRVIP-60-A (EPRI 1008871), BWR Vessel and Internals Project, Evaluation of Stress Corrosion Crack Growth in Low Alloy Steel Vessel Materials in the BWR Environment, Final Safety Evaluation Report by the Office of Nuclear Reactor Regulation, June 2003.
BWRVIP-62 (EPRI 108705), BWR Vessel and Internals Project, Technical Basis for Inspection Relief for BWR Internal Components with Hydrogen Injection, March 7, 2000.
BWRVIP-76-A (EPRI 1019057), BWR Vessel and Internals Project, BWR Core Shroud Inspection and Flaw Evaluation Guidelines, December 2009.
BWRVIP-80NP-A, (EPRI 1015457NP), BWR Vessel and Internals Project, Evaluation of Crack Growth in BWR Shroud Vertical Welds, October 2007.
BWRVIP 99 A, (EPRI 1016566), BWR Vessel and Internals Project, Crack Growth Rates in Irradiated Stainless Steels in BWR Internal Components, Final Report, October 2008.
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BWRVIP-139 (EPRI 1011463), BWR Vessel and Internals Project, Steam Dryer Inspection and Flaw Evaluation Guidelines, Final Safety Evaluation Report by the Office of Nuclear Reactor Regulation, April 2005.
BWRVIP-167NP (EPRI 1018111) Rev. 1: BWR Vessel and Internals Project Boiling Water Reactor Issue Management Tables, Final Report, September 2008.
BWRVIP-181 (EPRI1013403), BWR Vessel and Internals Project, Steam Dryer Repair Design Criteria, Final Safety Evaluation Report by the Office of Nuclear Reactor Regulation, November 2007.
BWRVIP-183 (EPRI 1013401), BWR Vessel and Internals Project, Top Guide Beam Inspection and Flaw Evaluation Guidelines, December 2007.
BWRVIP-190 (EPRI 1016579), BWR Vessel and Internals Project: BWR Water Chemistry Guidelines-200B Revision, October 2008.
EPRI 1016486, Primary System Corrosion Research Program, EPRI Materials Degradation Matrix, Rev. 1, Final Report, May 2008.
Lee, S., Kuo, P. T., Wichman, K., and Chopra, 0., Flaw Evaluation of Thermally Aged Cast Stainless Steel in Light-Water Reactor Applications, Int. J. Pres. Ves. and Piping, pp. 37-44, 1997.
Letter from Christopher I. Grimes, U.S. Nuclear Regulatory Commission, License Renewal and Standardization Branch, to Douglas J. Walters, Nuclear Energy Institute, License Renewal Issue No. 98-0030, Thermal Aging Embrittlement of Cast Stainless Steel Components, May 19, 2000. (ADAMS Accession No. ML003717179)
NRC Bulletin No. 80-07, BWR Jet Pump Assembly Failure, U.S. Nuclear Regulatory Commission, April 4, 1980.
NRC Bulletin No. 80-13, Cracking in Core Spray Spargers, U.S. Nuclear Regulatory Commission, May 12, 1980.
NRC Bulletin No. 80-07, Supplement 1, BWR Jet Pump Assembly Failure, U.S. Nuclear Regulatory Commission, May 13, 1980.
NRC Generic Letter 94-03, Intergranular Stress Corrosion Cracking of Core Shrouds in Boiling Water Reactors, U.S. Nuclear Regulatory Commission, July 25, 1994.
NRC Information Notice 88-03, Cracks in Shroud Support Access Hole Cover Welds, U.S. Nuclear Regulatory Commission, February 2, 1988.
NRC Information Notice 92-57, Radial Cracking of Shroud Support Access Hole Cover Welds, U.S. Nuclear Regulatory Commission, August 11, 1992.
NRC Information Notice 93-101, Jet Pump Hold-Down Beam Failure, U.S. Nuclear Regulatory Commission, December 17, 1993.
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NRC Information Notice 94-42, Cracking in the Lower Region of the Core Shroud in Boiling Water Reactors, U.S. Nuclear Regulatory Commission, June 7,1994.
NRC Information Notice 95-17, Reactor Vessel Top Guide and Core Plate Cracking, U.S. Nuclear Regulatory Commission, March 10, 1995.
NRC Information Notice 97-02, Cracks Found in Jet Pump Riser Assembly Elbows at Boiling Water Reactors, U.S. Nuclear Regulatory Commission, February 6, 1997.
NRC Information Notice 97-17, Cracking of Vertical Welds in the Core Shroud and Degraded Repair, U.S. Nuclear Regulatory Commission, April 4, 1997.
NRC Information Notice 2007-02, Failure of Control Rod Drive Mechanism Lead Screw Male Coupling at Babcock and Wilcox-Designed Facility. (ADAMS Accession No. ML070100459)
NUREG-1544, Status Report: Intergranular Stress Corrosion Cracking of BWR Core Shrouds and Other Internal Components, U.S. Nuclear Regulatory Commission, March 1996.
NUREG/CR-4513, Rev. 1, Estimation of Fracture Toughness of Cast Stainless Steels during Thermal Aging in LWR Systems, U.S. Nuclear Regulatory Commission, August 1994.
NUREG/CR-6923, P. L. Andresen, F. P. Ford, K. Gott, R. L. Jones, P. M. Scott, T. Shoji, R. W.
Staehle, and R. L. Tapping, Expert Panel Report on Proactive Materials Degradation Assessment, U.S. Nuclear Regulatory Commission, Washington, DC, 3895 pp. March 2007.
Xu, H. and Fyfitch, S., Fracture of Type 17-4 PH CRDM Lead Screw Male Coupling Tangs. The 11th International Conference on Environmental Degradation of Materials in Nuclear Power Systems-Water Reactors, ANS: Stevenson, WA (2003).
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XI.M10 BORIC ACID CORROSION Program Description The program relies in part on implementation of recommendations in Nuclear Regulatory Commission (NRC) Generic Letter (GL) 88-05 to monitor the condition of the reactor coolant pressure boundary for borated water leakage. Periodic visual inspection of adjacent structures, components, and supports for evidence of leakage and corrosion is an element of the NRC GL 88-05 monitoring program. Potential improvements to boric acid corrosion programs have been identified because of recent operating experience with cracking of certain nickel alloy pressure boundary components (NRC Regulatory Issue Summary 2003-013).
Borated water leakage from piping and components that are outside the scope of the program established in response to NRC GL 88-05 may affect structures and components that are subject to aging management review (AMR). Therefore, the scope of the monitoring and inspections of this program includes all components that contain borated water and that are in proximity to structures and components that are subject to AMR. The scope of the evaluations, assessments, and corrective actions include all observed leakage sources and the affected structures and components.
Borated water leakage may be discovered through activities other than those established specifically to detect such leakage. Therefore, the program includes provisions for triggering evaluations and assessments when leakage is discovered by other activities. The effects of boric acid corrosion on reactor coolant pressure boundary materials in the vicinity of nickel alloy components are managed by GALL AMP XI.M11 B, "Cracking of Nickel-Alloy Components and Loss of Material Due to Boric Acid-induced Corrosion in Reactor Coolant Pressure Boundary Components."
Evaluation and Technical Basis
- 1. Scope of Program: The program covers any structures or components on which boric acid corrosion may occur (e.g., steel, copper alloy >15% zinc, and aluminum) and electrical components onto which borated reactor water may leak. The program includes provisions in response to the recommendations of NRC GL 88-05. NRC GL 88-05 provides a program consisting of systematic measures to ensure that corrosion caused by leaking borated coolant does not lead to degradation of the leakage source or adjacent structures and components, and provides assurance that the reactor coolant pressure boundary will have an extremely low probability of abnormal leakage, rapidly propagating failure, or gross rupture. Such a program provides for (a) determination of the principal location of leakage, (b) examinations and procedures for locating small leaks, and (c) engineering evaluations and corrective actions to ensure that boric acid corrosion does not lead to degradation of the leakage source or adjacent structures or components, which could cause the loss of intended function of the structures or components.
- 2. Preventive Actions: This program is a condition monitoring program; thus, there are no preventive actions. However, minimizing reactor coolant leakage by frequent monitoring of the locations where potential leakage could occur and timely repair if leakage is detected prevents or mitigates boric acid corrosion.
- 3. Parameters Monitored/Inspected: The aging management program monitors the aging effects of loss of material due to boric acid corrosion on the intended function of an affected December 201 0 XI M10-1 NUREG-1801, Rev. 2 OAG10001390_00579
structure and component by detection of borated water leakage. Borated water leakage results in deposits of white boric acid crystals and the presence of moisture that can be observed by visual examination. Boric acid deposits, borated water leakage, or the presence of moisture that could lead to the identification of loss of material can be monitored through visual examination.
- 4. Detection of Aging Effects: Degradation of the component due to boric acid corrosion cannot occur without leakage of borated water. Conditions leading to boric acid corrosion, such as crystal buildup and evidence of moisture, are readily detectable by visual inspection, though removal of insulation may be required in some cases. However, for leakage examinations of components with external insulation surfaces and joints under insulation or not visible for direct visual examination, the surrounding area (including the floor, equipment surfaces, and other areas where leakage may be channeled) is examined for evidence of component leakage. Discoloration, staining, boric acid residue, and other evidence of leakage on insulation surfaces and the surrounding area are given particular consideration as evidence of component leakage. If evidence of leakage is found, removal of insulation to determine the exact source may be required. The program delineated in NRC GL 88-05 includes guidelines for locating small leaks, conducting examinations, and performing engineering evaluations. In addition, the program includes appropriate interfaces with other site programs and activities, such that borated water leakage that is encountered by means other than the monitoring and trending established by this program is evaluated and corrected. Thus, the use of the NRC GL 88-05 program assures detection of leakage before the loss of the intended function of the affected components.
- 5. Monitoring and Trending: The program provides monitoring and trending activities as delineated in NRC GL 88-05, timely evaluation of evidence of borated water leakage identified by other means, and timely detection of leakage by observing boric acid crystals during normal plant walkdowns and maintenance.
- 6. Acceptance Criteria: Any detected borated water leakage, white or discolored crystal buildup, or rust-colored deposits are evaluated to confirm or restore the intended functions of affected structures and components consistent with the design basis prior to continued service.
- 7. Corrective Actions: The NRC finds that the requirements of 10 CFR Part 50, Appendix B, with additional consideration of the guidance in NRC GL 88-05, are acceptable to implement the corrective actions related to this program. Borated water leakage and areas of resulting boric acid corrosion are evaluated and corrected in accordance with the applicable provisions of NRC GL 88-05 and the corrective action program. Any detected boric acid crystal buildup or deposits should be cleaned. NRC GL 88-05 recommends that corrective actions to prevent recurrences of degradation caused by borated water leakage be included in the program implementation. These corrective actions include any modifications to be introduced in the present design or operating procedures of the plant that (a) reduce the probability of primary coolant leaks at locations where they may cause corrosion damage and (b) entail the use of suitable corrosion resistant materials or the application of protective coatings or claddings.
- 8. Confirmation Process: Site quality assurance (QA) procedures, review and approval processes, and administrative controls are implemented in accordance with the requirements of 10 CFR Part 50, Appendix B. As discussed in the Appendix for GALL, the NUREG-1801, Rev. 2 XI M10-2 December 201 0 OAG10001390_00580
staff finds the requirements of 10 CFR Part SO, Appendix B, acceptable to address the confirmation process and administrative controls.
- 9. Administrative Controls: The administrative controls for this program provide for a formal review and approval of corrective actions. The administrative controls for this program are implemented through the site's QA program in accordance with the requirements of 10 CFR Part SO, Appendix B.
- 10. Operating Experience: Boric acid corrosion has been observed in nuclear power plants (NRC Information Notice [IN] 86-108 [and supplements 1 through 3] and NRC IN 2003-02) and has resulted in significant impairment of component-intended functions in areas that are difficult to access/observe (NRC Bulletin 2002-01).
References 10 CFR Part SO, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
10 CFR SO.SSa, Codes and Standards, Office of the Federal Register, National Archives and Records Administration, 2009.
NRC Generic Letter 88-0S, Boric Acid Corrosion of Carbon Steel Reactor Pressure Boundary Components in PWR Plants, U.S. Nuclear Regulatory Commission, March 17, 1988.
NRC Information Notice 86-108, Degradation of Reactor Coolant System Pressure Boundary Resulting from Boric Acid Corrosion, U.S. Nuclear Regulatory Commission, December 26, 1986; Supplement 1, April 20, 1987; Supplement 2, November 19,1987; and Supplement 3, January S, 1995.
NRC Bulletin 2002-01, Reactor Pressure Vessel Head Degradation and Reactor Coolant Pressure Boundary Integrity, U.S. Nuclear Regulatory Commission, March 18, 2002.
NRC Bulletin 2002-02, Reactor Pressure Vessel Head and Vessel Head Penetration Nozzle Inspection Programs, U.S. Nuclear Regulatory Commission, August 9,2002.
NRC Information Notice 2002-11, Recent Experience with Degradation of Reactor Pressure Vessel Head, U.S. Nuclear Regulatory Commission, March 12, 2002.
NRC Information Notice 2002-13, Possible Indicators of Ongoing Reactor Pressure Vessel Head Degradation, U.S. Nuclear Regulatory Commission, April 4,2002.
NRC Information Notice 2003-02, Recent Experience with Reactor Coolant System Leakage and Boric Acid Corrosion, U.S. Nuclear Regulatory Commission, January 16, 2003.
NRC Regulatory Issue Summary 2003-013, NRC Review of Responses to Bulletin 2002-01,
'Reactor Pressure Vessel Head Degradation and Reactor Coolant Pressure Boundary Integrity,' U.S. Nuclear Regulatory Commission, July 29,2003.
NUREG-1823, U.S. Plant Experience with Alloy 600 Cracking and Boric Acid Corrosion of Light-Water Reactor Pressure Vessel Materials, U.S. Nuclear Regulatory Commission, April 200S.
December 201 0 XI M10-3 NUREG-1801, Rev. 2 OAG10001390_00S81
XI.M11B CRACKING OF NICKEL-ALLOY COMPONENTS AND LOSS OF MATERIAL DUE TO BORIC ACID-INDUCED CORROSION IN REACTOR COOLANT PRESSURE BOUNDARY COMPONENTS (PWRs ONLY)
Program Description This program replaces AMPs XI.M11, "Nickel-Alloy Nozzles and Penetrations" and XI.M11A, "Nickel-Alloy Penetration Nozzles Welded to the Upper Reactor Vessel Closure Heads of Pressurized Water Reactors." It addresses the issue of cracking of nickel-alloy components and loss of material due to boric acid-induced corrosion in susceptible, safety-related components in the vicinity of nickel-alloy reactor coolant pressure boundary components. A final rule (September 2008) updating 10 CFR 50.55a requires the following American Society of Mechanical Engineer (ASME) Boiler and Pressure Vessel (B&PV) Code Cases: (a) N-722, "Additional Examinations for PWR Pressure Retaining Welds in Class 1 Components Fabricated with Alloy 600/82/182 Materials,Section XI, Division 1" to establish long-term inspection requirements for the pressurized water reactor (PWR) vessel, steam generator, pressurizer components and piping if they contain the primary water stress corrosion cracking (PWSCC) susceptible materials designated alloys 600/82/182; and (b) N-729-1, "Alternative Examination Requirements for PWR Reactor Vessel Upper Heads With Nozzles Having Pressure-Retaining Partial-Penetration Welds,Section XI, Division 1" to establish new requirements for the long-term inspection of reactor pressure vessel upper heads.
In addition, dissimilar metal welds need additional examinations to provide reasonable assurance of structural integrity. The U.S. Nuclear Regulatory Commission (NRC) issued Regulatory Information Summary (RIS) 2008-25, "Regulatory Approach for Primary Water Stress Corrosion Cracking (PWSCC) of Dissimilar Metal Butt Welds in Pressurized Water Reactor Primary Coolant System Piping" (October 2008) which stated the regulatory approach for addressing PWSCC of dissimilar metal butt welds. The RIS documents the NRC's approach to ensuring the integrity of primary coolant system piping containing dissimilar metal butt welds in PWRs and, in conjunction with the mandated inspections of ASME Code Case N-722, ensures that augmented in-service inspections (lSI) of all nickel-based alloy components and welds in the reactor coolant system (RCS) continue to perform their intended functions.
As stated in this RIS, the NRC has found that MRP-139, "Primary System Piping Butt Weld Inspection and Evaluation Guideline" (2005), and MRP interim guidance letters provide adequate protection of public health and safety for addressing PWSCC in dissimilar metal butt welds pending the incorporation of ASME Code Case N-770, containing comprehensive inspection requirements, into 10 CFR 50.55a. It is the intention of the NRC to replace MRP-139 by incorporating the requirements of ASME Code Case N-770 into 10 CFR 50.55a.
The impacts of boric acid leakage from non-nickel alloy reactor coolant pressure boundary components are addressed in AMP XI.M10, "Boric Acid Corrosion." The Water Chemistry program for PWRs relies on monitoring and control of reactor water chemistry based on industry guidelines as described in AMP XI.M2, "Water Chemistry."
Evaluation and Technical Basis
- 1. Scope of Program: The program is focused on managing the effects of cracking due to PWSCC of all susceptible nickel alloy-based components of the reactor coolant pressure boundary (including nickel-alloy welds). The program also manages the loss of material due to boric acid corrosion in susceptible components in the vicinity of nickel-alloy components.
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These components could include, but are not limited to, the reactor vessel components (reactor pressure vessel upper head), steam generator components (nozzle-to-pipe connections, instrument connections, and drain tube penetrations), pressurizer components (nozzle-to-pipe connections, instrument connections, and heater penetrations), and reactor coolant system piping (instrument connections and full penetration welds).
- 2. Preventive Actions: This program is a condition monitoring program and does not include preventive or mitigative measures. However, maintaining high water purity reduces susceptibility to PWSCC. Reactor coolant water chemistry is monitored and maintained in accordance with the Water Chemistry program. The program description and the evaluation and technical basis of monitoring and maintaining reactor water chemistry are presented in GALL AMP XI.M2, "Water Chemistry."
At the discretion of the applicant, preventive actions to mitigate PWSCC may be addressed by various measures (e.g., weld overlays, replacement of components with more PWSCC-resistant materials, etc.).
- 3. Parameters Monitored/Inspected: This is a condition monitoring program that monitors cracking/PWSCC for nickel-alloy components and loss of material by boric acid corrosion for potentially affected steel component. Reactor coolant pressure boundary cracking and leakage are monitored by the applicant's in-service inspection program in accordance with 10 CFR 50.55a and industry guidelines (e.g., MRP-139). Boric acid deposits, borated water leakage, or the presence of moisture that could lead to the identification of cracking or loss of material can be monitored through visual examination.
- 4. Detection of Aging Effects: The program detects the effect of aging by various methods, including non-destructive examination techniques. Reactor coolant pressure boundary leakage can be monitored through the use of radiation air monitoring and other general area radiation monitoring, and technical specifications for reactor coolant pressure boundary leakage. The specific types of non-destructive examinations are dependent on the component's susceptibility to PWSCC and its accessibility to inspection. Inspection methods, schedules, and frequencies for the susceptible components are implemented in accordance with 10 CFR 50.55a and industry guidelines (e.g., MRP-139).
- 5. Monitoring and Trending: Reactor coolant pressure boundary leakage is calculated and trended on a routine basis in accordance with technical specification to detect changes in the leakage rates. Flaw evaluation through 10 CFR 50.55a is a means to monitor cracking.
- 6. Acceptance Criteria: Acceptance criteria for all indications of cracking and loss of material due to boric acid-induced corrosion are defined in 10 CFR 50.55a and industry guidelines (e.g., MRP-139).
- 7. Corrective Actions: Relevant flaw indications of susceptible components within the scope of this program found to be unacceptable for further services are corrected through implementation of appropriate repair or replacement as dictated by 10 CFR 50.55a and industry guidelines (e.g., MRP-139). In addition, detection of leakage or evidence of cracking in susceptible components within the scope of this program require scope expansion of current inspection and increased inspection frequencies of some components, as required by 10 CFR 50.55a and industry guidelines (e.g., MRP-139).
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Repair and replacement procedures and activities must either comply with ASME Section XI, as incorporated in 10 CFR 50.55a or conform to applicable ASME Code Cases that have been endorsed in 10 CFR 50.55a by referencing the latest version of NRC Regulatory Guide 1.147.
As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions.
- 8. Confirmation Process: Site quality assurance procedures and review and approval processes are implemented in accordance with the requirements of 10 CFR Part 50, Appendix B. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address confirmation process.
- 9. Administrative Controls: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the administrative controls.
- 10. Operating Experience: This new program addresses reviews of related operating experience, including plant-specific information, generic industry findings, and international data. Within the current regulatory requirements, as necessary, the applicant maintains a record of operating experience through the required update of the facility's inservice inspection program in accordance with 10 CFR 50.55a. Additionally, the applicant follows mandated industry guidelines developed to address operating experience in accordance with NEI-03-08, "Guideline for the Management of Materials Issues."
Cracking of Alloy 600 has occurred in domestic and foreign PWRs (NRC Information Notice
[IN] 90-10). Furthermore, ingress of demineralizer resins also has occurred in operating plants (NRC IN 96-11). The Water Chemistry program, AMP XI.M2, manages the effects of such excursions through monitoring and control of primary water chemistry. NRC GL 97-01 is effective in managing the effect of PWSCC. PWSCC also is occurring in the vessel head penetration (VHP) nozzle of U.S. PWRs as described in NRC Bulletins 2001-01,2002-01 and 2002-02.
References 10 CFR Part 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
10 CFR Part 50.55a, Codes and Standards, Office of the Federal Register, National Archives and Records Administration, 2009.
ASME Code Case N-722, Additional Examinations for PWR Pressure Retaining Welds in Class 1 Components Fabricated with Alloy 6001821182 Materials, July 5, 2005.
ASM E Code Case N-729-1, Alternative Examination Requirements for PWR Reactor Vessel Upper Heads with Nozzles Having Pressure-Retaining Partial-Penetration Welds, March 28, 2006.
ASME Code Case N-770, Alternative Examination Requirements and Acceptance Standards for Class 1 PWR Piping and Vessel Nozzle Butt Welds Fabricated with UNS N06082 or UNS December 201 0 XI M11 8-3 NUREG-1801, Rev. 2 OAG10001390_00584
W86182 Weld Filler Material With or Without Application of Listed Mitigation Activities, January 26, 2009.
MRP-139, Revision 1, Primary System Piping Butt Weld Inspection and Evaluation Guideline, Materials Reliability Program, December 16,2008.
NEI-03-08, Guideline for the Management of Materials Issues, Nuclear Energy Institute, May 2003.
NRC Bulletin 2001-01, Circumferential Cracking of Reactor Pressure Vessel Head Penetration Nozzles, U.S. Nuclear Regulatory Commission, August 3,2001.
NRC Bulletin 2002-01, Reactor Pressure Vessel Head Degradation and Reactor Coolant Pressure Boundary Integrity, U.S. Nuclear Regulatory Commission, March 18,2002.
NRC Bulletin 2002-02, Reactor Pressure Vessel Head and Vessel Head Penetration Nozzle Inspection Programs, U.S. Nuclear Regulatory Commission, August 9,2002.
NRC Generic Letter 97-01, Degradation of Control Rod Drive Mechanism Nozzle and Other Vessel Closure Head Penetrations, U.S. Nuclear Regulatory Commission, April 1, 1997.
NRC Information Notice 90-10, Primary Water Stress Corrosion Cracking (PWSCC) of Inconel 600, U.S. Nuclear Regulatory Commission, February 23, 1990.
NRC Information Notice 96-11, Ingress of Demineralizer Resins Increases Potential for Stress Corrosion Cracking of Control Rod Drive Mechanism Penetrations, U.S. Nuclear Regulatory Commission, February 14, 1996.
NRC Inspection Manual, Inspection Procedure 71111.08, Inservice Inspection Activities, March 23,2009.
NRC Inspection Manual, Temporary Instruction 2515/172, Reactor Coolant System Dissimilar Metal Butt Welds, February 21,2008.
NRC Regulatory Guide 1.147, Revision 15, Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1, U.S. Nuclear Regulatory Commission, January 2004.
NRC Regulatory Information Summary 2008-25, Regulatory Approach for Primary Water Stress Corrosion Cracking of Dissimilar Metal Butt Welds in Pressurized Water Reactor Primary Coolant System Piping, U.S. Nuclear Regulatory Commission, October 22,2008.
NUREG-1823, U.S. Plant Experience with Alloy 600 Cracking and Boric Acid Corrosion of Light-Water Reactor Pressure Vessel Materials, U.S. Nuclear Regulatory Commission, April 2005.
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XI.M12 THERMAL AGING EMBRITTLEMENT OF CAST AUSTENITIC STAINLESS STEEL (CASS)
Program Description The reactor coolant system components are inspected in accordance with the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI. This inspection is augmented to detect the effects of loss of fracture toughness due to thermal aging embrittlement of cast austenitic stainless steel (CASS) piping components except for pump casings and valve bodies. This aging management program (AMP) includes determination of the susceptibility of CASS components to thermal aging embrittlement based on casting method, molybdenum (Mo) content, and percent ferrite. For "potentially susceptible" components, as defined below, aging management is accomplished through either (a) qualified visual inspections, such as enhanced visual examination (EVT-1); (b) a qualified ultrasonic testing (UT) methodology; or (c) a component-specific flaw tolerance evaluation in accordance with the ASME Code,Section XI, 2004 edition.10 Additional inspection or evaluations to demonstrate that the material has adequate fracture toughness are not required for components that are not susceptible to thermal aging embrittlement.
For pump casings and valve bodies, based on the results of the assessment documented in the letter dated May 19, 2000, from Christopher Grimes, Nuclear Regulatory Commission (NRC), to Douglas Walters, Nuclear Energy Institute (NEI) (May 19, 2000 NRC letter), screening for susceptibility to thermal aging embrittlement is not required. The existing ASME Code,Section XI inspection requirements, including the alternative requirements of ASME Code Case N-481 for pump casings, are adequate for all pump casings and valve bodies.
Aging management of CASS reactor internal components of pressurized water reactors (PWRs) are discussed in AMP XI.M16A and of CASS reactor internal components of boiling water reactors (BWRs) in AMP XI.M9.
Evaluation and Technical Basis
- 1. Scope of Program: This program manages loss of fracture toughness in potentially susceptible ASME Code Class 1 piping components made from CASSo The program includes screening criteria to determine which CASS components are potentially susceptible to thermal aging embrittlement and require augmented inspection. The screening criteria are applicable to all primary pressure boundary components constructed from cast austenitic stainless steel with service conditions above 250°C (482°F). The screening criteria for susceptibility to thermal aging embrittlement are not applicable to niobium-containing steels; such steels require evaluation on a case-by-case basis.
Based on the criteria set forth in the May 19, 2000, NRC letter, the susceptibility to thermal aging embrittlement of CASS materials is determined in terms of casting method, molybdenum content, and ferrite content. For low-molybdenum content steels (SA-351 Grades CF3, CF3A, CF8, CF8A or other steels with:::; 0.5 weight percent [wt.%] Mo), only static-cast steels with >20% ferrite are potentially susceptible to thermal embrittlement.
Static-cast low-molybdenum steels with :'S:20% ferrite and all centrifugal-cast low-molybdenum steels are not susceptible. For high-molybdenum content steels (SA-351 Grades CF3M, CF3MA, and CF8M or other steels with 2.0 to 3.0 wt.% Mo), static-cast 10 Refer to the GALL Report, Chapter I, for applicability of other editions of ASME Code,Section XI.
December 201 0 XI M12-1 NUREG-1801, Rev. 2 OAG10001390_00586
steels with >14% ferrite and centrifugal-cast steels with >20% ferrite are potentially susceptible to thermal embrittlement. Static-cast high-molybdenum steels with :'S:14% ferrite and centrifugal-cast high-molybdenum steels with :'S:20% ferrite are not susceptible. In the susceptibility screening method, ferrite content is calculated by using the Hull's equivalent factors (described in NUREG/CR-4513, Rev. 1) or a staff-approved method for calculating delta ferrite in CASS materials. A fracture toughness value of 255 kilojoules per square meter (kJ/m 2) (1,450 inches-pounds per square inch) at a crack depth of 2.5 millimeters (0.1 inch) is used to differentiate between CASS materials that are not susceptible and those that are potentially susceptible to thermal aging embrittlement. Extensive research data indicate that for CASS materials not susceptible to thermal aging embrittlement, the saturated lower-bound fracture toughness is greater than 255 kJ/m 2 (NUREG/CR-4513, Rev. 1).
For pump casings and valve bodies, screening for susceptibility to thermal aging embrittlement is not needed (and thus there are no aging management review line items).
For all pump casings and valve bodies greater than a nominal pipe size (NPS) of 4 inches, the existing ASME Code,Section XI inspection requirements, including the alternative requirements of ASME Code Case N-481 for pump casings, are adequate. ASME Code,Section XI, Subsection IWB requires only surface examination of valve bodies less than a NPS of 4 inches. For these valve bodies less than a NPS of 4 inches, the adequacy of inservice inspection (lSI) according to ASME Code,Section XI has been demonstrated by an NRC-performed bounding integrity analysis (May 19, 2000 letter).
- 2. Preventive Actions: This program is a condition monitoring program and does not mitigate thermal aging embrittlement.
- 3. Parameters Monitored/Inspected: The program monitors the effects of loss of fracture toughness on the intended function of the component by identifying the CASS materials that are susceptible to thermal aging embrittlement.
The program does not directly monitor for loss of fracture toughness that is induced by thermal aging; instead, the impact of loss of fracture toughness on component integrity is indirectly managed by using visual or volumetric examination techniques to monitor for cracking in the components.
- 4. Detection of Aging Effects: For pump casings, valve bodies, and other "not susceptible" CASS piping components, no additional inspection or evaluations are needed to demonstrate that the material has adequate fracture toughness.
For "potentially susceptible" piping components, the AMP provides for qualified inspections of the base metal, such as enhanced visual examination (EVT-1) or a qualified UT methodology, with the scope of the inspection covering the portions determined to be limiting from the standpoint of applied stress, operating time, and environmental considerations. Examination methods that meet the criteria of the ASME Code,Section XI, Appendix VIII are acceptable. Alternatively, a plant-specific or component-specific flaw tolerance evaluation, using specific geometry, stress information, material properties, and ASME Code,Section XI can be used to demonstrate that the thermally-embrittled material has adequate toughness. Current UT methodology cannot detect and size cracks; thus, EVT-1 is used until qualified UT methodology for CASS can be established. A description of EVT-1 is found in Boiling Water Reactor Vessel and Internals Project (BWRVIP)-03 (Revision 6) and Materials Reliability Program (MRP)-228 for PWRs.
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- 5. Monitoring and Trending: Inspection schedules in accordance with ASME Code,Section XI, IWB-2400 or IWC-2400, reliable examination methods, and qualified inspection personnel provide timely and reliable detection of cracks. If flaws are detected, the period of acceptability is determined from analysis of the flaw, depending on the crack growth rate and mechanism.
- 6. Acceptance Criteria: Flaws detected in CASS components are evaluated in accordance with the applicable procedures of ASME Code,Section XI, IWB-3S00 or ASME Code,Section XI, IWC-3S00. Flaw tolerance evaluation for components with ferrite content up to 2S% is performed according to the principles associated with ASME Code,Section XI, IWB-3640 procedures for SAWs, disregarding the ASME Code restriction of 20% ferrite.
Extensive research data indicates that the lower-bound fracture toughness of thermally aged CASS materials with up to 2S% ferrite is similar to that for SAWs with up to 20% ferrite (Lee et ai., 1997). Flaw tolerance evaluation for piping with >2S% ferrite is performed on a case-by-case basis by using the applicant's fracture toughness data.
- 7. Corrective Actions: Repair and replacement are performed in accordance with ASME Code,Section XI, IWA-4000. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part SO, Appendix B acceptable to address the corrective actions.
- 8. Confirmation Process: Site quality assurance procedures, review and approval processes, and administrative controls are implemented in accordance with the requirements of 10 CFR Part SO, Appendix B. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part SO, Appendix B acceptable to address the confirmation process and administrative controls.
- 9. Administrative Controls: The administrative controls for this program provide for a formal review and approval of corrective actions. The administrative controls for this program are implemented through the site's QA program in accordance with the requirements of 10 CFR Part SO, Appendix B.
- 10. Operating Experience: The AMP was developed by using research data obtained on both laboratory-aged and service-aged materials. Based on this information, the effects of thermal aging embrittlement on the intended function of CASS components will be effectively managed.
References 10 CFR Part SO, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
10 CFR Part SO.SSa, Codes and Standards, Office of the Federal Register, National Archives and Records Administration, 2009.
ASME Section XI, Rules for In service Inspection of Nuclear Power Plant Components, The ASME Boiler and Pressure Vessel Code, 2004 edition as approved in 10 CFR SO.SSa, The American Society of Mechanical Engineers, New York, NY.
ASME Code Case N-481, Alternative Examination Requirements for Cast Austenitic Pump Casings,Section XI, Division 1.
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BWRVIP-03, Rev. 6, BWR Vessel and Internals Project: Reactor Pressure Vessel and Internals Examination Guidelines (EPRI TR-105696).
Lee, S., Kuo, P. T., Wichman, K., and Chopra, 0., Flaw Evaluation of Thermally-Aged Cast Stainless Steel in Light-Water Reactor Applications, Int. J. Pres. Vessel and Piping, pp 37-44, 1997.
Letter from Christopher I. Grimes, U.S. Nuclear Regulatory Commission, License Renewal and Standardization Branch, to Douglas J. Walters, Nuclear Energy Institute, License Renewal Issue No. 98-0030, Thermal Aging Embrittlement of Cast Stainless Steel Components, May 19, 2000. (ADAMS Accession No. ML003717179)
Letter from Mark J. Maxin, to Rick Libra (BWRVIP Chairman), Safety Evaluation for Electric Power Research Institute (EPRI) Boiling Water Reactor Vessel and Internals project (BWRVIP) Report TR-105696-R6 (BWRVIP-03), Revision 6, BWR Vessel and Internals Examination Guidelines (TAC No MC2293)," June 30, 2008 (ADAMS Accession No ML081500814)
MRP-228, Materials Reliability Program: Inspection Standard for PWR Internals, 2009.
NUREG/CR-4513, Rev. 1, Estimation of Fracture Toughness of Cast Stainless Steels During Thermal Aging in LWR Systems, U.S. Nuclear Regulatory Commission, August 1994.
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XI.M16A PWR VESSEL INTERNALS Program Description This program relies on implementation of the Electric Power Research Institute (EPRI) Report No. 1016596 (MRP-227) and EPRI Report No. 1016609 (MRP-228) to manage the aging effects on the reactor vessel internal (RVI) components.
This program is used to manage the effects of age-related degradation mechanisms that are applicable in general to the PWR RVI components at the facility. These aging effects include (a) various forms of cracking, including stress corrosion cracking (SCC), which also encompasses primary water stress corrosion cracking (PWSCC), irradiation-assisted stress corrosion cracking (lASCC), or cracking due to fatigue/cyclical loading; (b) loss of material induced by wear; (c) loss of fracture toughness due to either thermal aging or neutron irradiation embrittlement; (d) changes in dimension due to void swelling; and (e) loss of preload due to thermal and irradiation-enhanced stress relaxation or creep.
The program applies the guidance in MRP-227 for inspecting, evaluating, and, if applicable, dispositioning non-conforming RVI components at the facility. The program conforms to the definition of a sampling-based condition monitoring program, as defined by the Branch Technical Position RSLB-1, with periodic examinations and other inspections of highly-affected internals locations. These examinations provide reasonable assurance that the effects of age-related degradation mechanisms will be managed during the period of extended operation. The program includes expanding periodic examinations and other inspections if the extent of the degradation effects exceeds the expected levels.
The MRP-227 guidance for selecting RVI components for inclusion in the inspection sample is based on a four-step ranking process. Through this process, the reactor internals for all three PWR designs were assigned to one of the following four groups: Primary, Expansion, Existing Programs, and No Additional Measures components. Definitions of each group are provided in GALL Chapter IX.B.
The result of this four-step sample selection process is a set of Primary Internals Component locations for each of the three plant designs that are expected to show the leading indications of the degradation effects, with another set of Expansion Internals Component locations that are specified to expand the sample should the indications be more severe than anticipated. The degradation effects in a third set of internals locations are deemed to be adequately managed by Existing Programs, such as ASME Code,Section XI, 11 Examination Category B-N-3 examinations of core support structures. A fourth set of internals locations are deemed to require no additional measures. As a result, the program typically identifies 5 to 15% of the RVI locations as Primary Component locations for inspections, with another 7 to 10% of the RVI locations to be inspected as Expansion Components, as warranted by the evaluation of the inspection results. Another 5 to 15% of the internals locations are covered by Existing Programs, with the remainder requiring no additional measures. This process thus uses appropriate component functionality criteria, age-related degradation susceptibility criteria, and failure consequence criteria to identify the components that will be inspected under the program in a manner that conforms to the sampling criteria for sampling-based condition monitoring programs in Section A.1.2.3.4 of NRC Branch Position RLSB-1. Consequently, the sample 11 Refer to the GALL Report, Chapter I, for applicability of various editions of the ASME Code,Section XI.
December 201 0 XI M16A-1 NUREG-1801, Rev. 2 OAG10001390_00590
selection process is adequate to assure that the intended function(s) of the PWR reactor internal components are maintained during the period of extended operation.
The program's use of visual examination methods in MRP-227 for detection of relevant conditions (and the absence of relevant conditions as a visual examination acceptance criterion) is consistent with the ASME Code,Section XI rules for visual examination. However, the program's adoption of the MRP-227 guidance for visual examinations goes beyond the ASME Code,Section XI visual examination criteria because additional guidance is incorporated into MRP-227 to clarify how the particular visual examination methods will be used to detect relevant conditions and describes in more detail how the visual techniques relate to the specific RVI components and how to detect their applicable age-related degradation effects.
The technical basis for detecting relevant conditions using volumetric ultrasonic testing (UT) inspection techniques can be found in MRP-228, where the review of existing bolting UT examination technical justifications has demonstrated the indication detection capability of at least two vendors, and where vendor technical justification is a requirement prior to any additional bolting examinations. Specifically, the capability of program's UT volumetric methods to detect loss of integrity of PWR internals bolts, pins, and fasteners, such as baffle-former bolting in B&W and Westinghouse units, has been well demonstrated by operating experience.
In addition, the program's adoption of the MRP-227 guidance and process incorporates the UT criteria in MRP-228, which calls for the technical justifications that are needed for volumetric examination method demonstrations, required by the ASME Code,Section V.
The program also includes future industry operating experience as incorporated in periodic revisions to MRP-227. The program thus provides reasonable assurance for the long-term integrity and safe operation of reactor internals in all commercial operating U.S. PWR nuclear power plants.
Age-related degradation in the reactor internals is managed through an integrated program.
Specific features of the integrated program are listed in the following ten program elements.
Degradation due to changes in material properties (e.g., loss of fracture toughness) was considered in the determination of inspection recommendations and is managed by the requirement to use appropriately degraded properties in the evaluation of identified defects. The integrated program is implemented by the applicant through an inspection plan that is submitted to the NRC for review and approval with the application for license renewal.
Evaluation and Technical Basis
- 1. Scope of Program: The scope of the program includes all RVI components at the [as an administrative action item for the AMP, the applicant to fill in the name of the applicant's nuclear facility, including applicable units], which [is/are] built to a [applicant to fill in Westinghouse, CE, or B&IN, as applicable] NSSS design. The scope of the program applies the methodology and guidance in the most recently NRC-endorsed version of MRP-227, which provides augmented inspection and flaw evaluation methodology for assuring the functional integrity of safety-related internals in commercial operating U.S. PWR nuclear power plants designed by B&W, CE, and Westinghouse. The scope of components considered for inspection under MRP-227 guidance includes core support structures (typically denoted as Examination Category B-N-3 by the ASME Code,Section XI), those RVI components that serve an intended license renewal safety function pursuant to criteria in 10 CFR 54.4(a)(1), and other RVI components whose failure could prevent satisfactory accomplishment of any of the functions identified in 10 CFR 54.4(a)(1)(i), (ii), or (iii). The NUREG-1801, Rev. 2 XI M16A-2 December 201 0 OAG10001390_00591
scope of the program does not include consumable items, such as fuel assemblies, reactivity control assemblies, and nuclear instrumentation, because these components are not typically within the scope of the components that are required to be subject to an aging management review (AMR), as defined by the criteria set in 10 CFR 54.21 (a)(1). The scope of the program also does not include welded attachments to the internal surface of the reactor vessel because these components are considered to be ASME Code Class 1 appurtenances to the reactor vessel and are adequately managed in accordance with an applicant's AMP that corresponds to GALL AMP XI.M1, "ASME Code,Section XI Inservice Inspection, Subsections IW8, IWC, and IWO."
The scope of the program includes the response bases to applicable license renewal applicant action items (LRAAls) on the MRP-227 methodology, and any additional programs, actions, or activities that are discussed in these LRAAI responses and credited for aging management of the applicant's RVI components. The LRAAls are identified in the staff's safety evaluation on MRP-227 and include applicable action items on meeting those assumptions that formed the basis of the MRP's augmented inspection and flaw evaluation methodology (as discussed in Section 2.4 of MRP-227), and NSSS vendor-specific or plant-specific LRAAls as well. The responses to the LRAAls on MRP-227 are provided in Appendix C of the LRA.
The guidance in MRP-227 specifies applicability limitations to base-loaded plants and the fuel loading management assumptions upon which the functionality analyses were based.
These limitations and assumptions require a determination of applicability by the applicant for each reactor and are covered in Section 2.4 of MRP-227.
- 2. Preventive Actions: The guidance in MRP-227 relies on PWR water chemistry control to prevent or mitigate aging effects that can be induced by corrosive aging mechanisms (e.g.,
loss of material induced by general, pitting corrosion, crevice corrosion, or stress corrosion cracking or any of its forms [SCC, PWSCC, or IASCC]). Reactor coolant water chemistry is monitored and maintained in accordance with the Water Chemistry Program. The program description, evaluation, and technical basis of water chemistry are presented in GALL AMP XI.M2, "Water Chemistry."
- 3. Parameters Monitored/Inspected: The program manages the following age-related degradation effects and mechanisms that are applicable in general to the RVI components at the facility: (a) cracking induced by SCC, PWSCC, IASCC, or fatigue/cyclical loading; (b) loss of material induced by wear; (c) loss of fracture toughness induced by either thermal aging or neutron irradiation embrittlement; (d) changes in dimension due to void swelling and irradiation growth, distortion, or deflection; and (e) loss of preload caused by thermal and irradiation-enhanced stress relaxation or creep. For the management of cracking, the program monitors for evidence of surface breaking linear discontinuities if a visual inspection technique is used as the non-destruction examination (NOE) method, or for relevant flaw presentation signals if a volumetric UT method is used as the NOE method. For the management of loss of material, the program monitors for gross or abnormal surface conditions that may be indicative of loss of material occurring in the components. For the management of loss of preload, the program monitors for gross surface conditions that may be indicative of loosening in applicable bolted, fastened, keyed, or pinned connections. The program does not directly monitor for loss of fracture toughness that is induced by thermal aging or neutron irradiation embrittlement, or by void swelling and irradiation growth; instead, the impact of loss of fracture toughness on component integrity is indirectly managed by using visual or volumetric examination techniques to monitor for cracking in the December 201 0 XI M16A-3 NUREG-1801, Rev. 2 OAG10001390_00592
components and by applying applicable reduced fracture toughness properties in the flaw evaluations if cracking is detected in the components and is extensive enough to warrant a supplemental flaw growth or flaw tolerance evaluation under the MRP-227 guidance or ASME Code,Section XI requirements. The program uses physical measurements to monitor for any dimensional changes due to void swelling, irradiation growth, distortion, or deflection.
Specifically, the program implements the parameters monitored/inspected criteria for [as an administrative action item for the AMP, applicant is to select one of the following to finish the sentence, as applicable to its NSSS vendor for its internals: "for B&W designed Primary Components in Table 4-1 of MRP-22T:* "for CE designed Primary Components in Table 4-2 of MRP-22T:* and "for Westinghouse designed Primary Components in Table 4-3 of MRP-227']. Additionally, the program implements the parameters monitored/inspected criteria for
[as an administrative action item for the AMP, applicant is to select one of the following to finish the sentence, as applicable to its NSSS vendor for its internals: "for B&W designed Expansion Components in Table 4-4 of MRP-22T:* "for CE designed Expansion Components in Table 4-5 of MRP-22T:* and "for Westinghouse designed Expansion Components in Table 4-6 of MRP-227']. The parameters monitored/inspected for Existing Program Components follow the bases for referenced Existing Programs, such as the requirements for ASME Code Class RVI components in ASME Code,Section XI, Table IW8-2500-1, Examination Categories 8-N-3, as implemented through the applicant's ASME Code,Section XI program, or the recommended program for inspecting Westinghouse-designed flux thimble tubes in GALL AMP XI.M37, "Flux Thimble Tube Inspection." No inspections, except for those specified in ASME Code,Section XI, are required for components that are identified as requiring "No Additional Measures," in accordance with the analyses reported in MRP-227.
- 4. Detection of Aging Effects: The detection of aging effects is covered in two places: (a) the guidance in Section 4 of MRP-227 provides an introductory discussion and justification of the examination methods selected for detecting the aging effects of interest; and (b) standards for examination methods, procedures, and personnel are provided in a companion document, MRP-228. In all cases, well-established methods were selected.
These methods include volumetric UT examination methods for detecting flaws in bolting, physical measurements for detecting changes in dimension, and various visual (VT-3, VT-1, and EVT-1) examinations for detecting effects ranging from general conditions to detection and sizing of surface-breaking discontinuities. Surface examinations may also be used as an alternative to visual examinations for detection and sizing of surface-breaking discontinuities.
Cracking caused by SCC, IASCC, and fatigue is monitored/inspected by either VT-1 or EVT-1 examination (for internals other than bolting) or by volumetric UT examination (bolting).
The VT-3 visual methods may be applied for the detection of cracking only when the flaw tolerance of the component or affected assembly, as evaluated for reduced fracture toughness properties, is known and has been shown to be tolerant of easily detected large flaws, even under reduced fracture toughness conditions. In addition, VT-3 examinations are used to monitor/inspect for loss of material induced by wear and for general aging conditions, such as gross distortion caused by void swelling and irradiation growth or by gross effects of loss of preload caused by thermal and irradiation-enhanced stress relaxation and creep.
In addition, the program adopts the recommended guidance in MRP-227 for defining the Expansion criteria that need to be applied to inspections of Primary Components and NUREG-1801, Rev. 2 XI M16A-4 December 201 0 OAGI0001390_00593
Existing Requirement Components and for expanding the examinations to include additional Expansion Components. As a result, inspections performed on the RVI components are performed consistent with the inspection frequency and sampling bases for Primary Components, Existing Requirement Components, and Expansion Components in MRP-227, which have been demonstrated to be in conformance with the inspection criteria, sampling basis criteria, and sample Expansion criteria in Section A.1.2.3.4 of NRC Branch Position RLSB-1.
Specifically, the program implements the parameters monitored/inspected criteria and bases for inspecting the relevant parameter conditions for [as an administrative action item for the AMP, applicant is to select one of the following to finish the sentence, as applicable to its NSSS vendor for its internals: "B&W designed Primary Components in Table 4-1 of MRP-227':* "CE designed Primary Components in Table 4-2 of MRP-227;" or "Westinghouse designed Primary Components in Table 4-3 of MRP-227'1 and for [as an administrative action item for the AMP, applicant is to select one of the following to finish the sentence, as applicable to its NSSS vendor for its internals: "for B&W designed Expansion Components in Table 4-4 of MRP-227;" "for CE designed expansion components in Table 4-5 of MRP-227;" and "for Westinghouse designed Expansion Components in Table 4-6 of MRP-227l The program is supplemented by the following plant-specific Primary Component and Expansion Component inspections for the program (as applicable): [As a relevant license renewal applicant action item, the applicant is to list (using criteria in MRP-227) each additional RVI component that needs to be inspected as an additional plant-specific Primary Component for the applicant's program and each additional RVI component that needs to be inspected as an additional plant-specific Expansion Component for the applicant's program.
For each plant specific component added as an additional primary or Expansion Component, the list should include the applicable aging effects that will be monitored for, the inspection method or methods used for monitoring, and the sample size and frequencies for the examinations].
In addition, in some cases (as defined in MRP-227), physical measurements are used as supplemental techniques to manage for the gross effects of wear, loss of preload due to stress relaxation, or for changes in dimension due to void swelling, deflection or distortion.
The physical measurements methods applied in accordance with this program include
[Applicant to input physical measure methods identified by the MRP in response to NRC RAI No. 11 in the NRC's Request for Additional Information to Mr. Christen B. Larson, EPRI MRP on Topical Report MRP-227 dated November 12,2009].
- 5. Monitoring and Trending: The methods for monitoring, recording, evaluating, and trending the data that result from the program's inspections are given in Section 6 of MRP-227 and its subsections. The evaluation methods include recommendations for flaw depth sizing and for crack growth determinations as well for performing applicable limit load, linear elastic and elastic-plastic fracture analyses of relevant flaw indications. The examinations and re-examinations required by the MRP-227 guidance, together with the requirements specified in MRP-228 for inspection methodologies, inspection procedures, and inspection personnel, provide timely detection, reporting, and corrective actions with respect to the effects of the age-related degradation mechanisms within the scope of the program. The extent of the examinations, beginning with the sample of susceptible PWR internals component locations identified as Primary Component locations, with the potential for inclusion of Expansion Component locations if the effects are greater than anticipated, plus the continuation of the Existing Programs activities, such as the ASME Code,Section XI, Examination Category B-December 201 0 XI M16A-S NUREG-1801, Rev. 2 OAGI0001390_00594
N-3 examinations for core support structures, provides a high degree of confidence in the total program.
- 6. Acceptance Criteria: Section 5 of MRP-227 provides specific examination acceptance criteria for the Primary and Expansion Component examinations. For components addressed by examinations referenced to ASME Code,Section XI, the IWB-3500 acceptance criteria apply. For other components covered by Existing Programs, the examination acceptance criteria are described within the Existing Program reference document.
The guidance in MRP-227 contains three types of examination acceptance criteria:
- For visual examination (and surface examination as an alternative to visual examination), the examination acceptance criterion is the absence of any of the specific, descriptive relevant conditions; in addition, there are requirements to record and disposition surface breaking indications that are detected and sized for length by VT-1/EVT-1 examinations;
- For volumetric examination, the examination acceptance criterion is the capability for reliable detection of indications in bolting, as demonstrated in the examination Technical Justification; in addition, there are requirements for system-level assessment of bolted or pinned assemblies with unacceptable volumetric (UT) examination indications that exceed specified limits; and
- For physical measurements, the examination acceptance criterion for the acceptable tolerance in the measured differential height from the top of the plenum rib pads to the vessel seating surface in B&W plants are given in Table 5-1 of MRP-227. The acceptance criterion for physical measurements performed on the height limits of the Westinghouse-designed hold-down springs are [The incorporation of this sentence is a license renewal applicant action item for Westinghouse PWR applicants only - insert the applicable sentence incorporating the specified physical measurement criteria only if the applicant's facility is based on a Westinghouse NSSS design: the Westinghouse applicant is to incorporate the applicable language and then specify the fit up limits on the hold down springs, as established on a plant-specific basis for the design of the hold-down springs at the applicant's Westinghouse-designed facility].
- 7. Corrective Actions: Corrective actions following the detection of unacceptable conditions are fundamentally provided for in each plant's corrective action program. Any detected conditions that do not satisfy the examination acceptance criteria are required to be dispositioned through the plant corrective action program, which may require repair, replacement, or analytical evaluation for continued service until the next inspection. The disposition will ensure that design basis functions of the reactor internals components will continue to be fulfilled for all licensing basis loads and events. Examples of methodologies that can be used to analytically disposition unacceptable conditions are found in the ASME Code,Section XI or in Section 6 of MRP-227. Section 6 of MRP-227 describes the options that are available for disposition of detected conditions that exceed the examination acceptance criteria of Section 5 of the report. These include engineering evaluation methods, as well as supplementary examinations to further characterize the detected condition, or the alternative of component repair and replacement procedures. The latter are subject to the requirements of the ASME Code,Section XI. The implementation of the guidance in MRP-227, plus the implementation of any ASME Code requirements, provides NUREG-1801, Rev. 2 XI M16A-6 December 201 0 OAGI0001390_00595
an acceptable level of aging management of safety-related components addressed in accordance with the corrective actions of 10 CFR Part 50, Appendix B or its equivalent, as applicable.
Other alternative corrective action bases may be used to disposition relevant conditions if they have been previously approved or endorsed by the NRC. Examples of previously NRC-endorsed alternative corrective actions bases include those corrective actions bases for Westinghouse-design RVI components that are defined in Tables 4-1, 4-2, 4-3, 4-4, 4-5, 4-6, 4-7 and 4-8 of Westinghouse Report No. WCAP-14577-Rev. 1-A, or for B&W-designed RVI components in B&W Report No. BAW-2248. Westinghouse Report No. WCAP-14577-Rev.
1-A was endorsed for use in an NRC SE to the Westinghouse Owners Group, dated February 10, 2001. B&W Report No. BAW-2248 was endorsed for use in an SE to Framatome Technologies on behalf of the B&W Owners Group, dated December 9, 1999.
Alternative corrective action bases not approved or endorsed by the NRC will be submitted for NRC approval prior to their implementation.
- 8. Confirmation Process: Site quality assurance procedures, review and approval processes, and administrative controls are implemented in accordance with the requirements of 10 CFR Part 50, Appendix B, or their equivalent, as applicable. It is expected that the implementation of the guidance in MRP-227 will provide an acceptable level of quality for inspection, flaw evaluation, and other elements of aging management of the PWR internals that are addressed in accordance with the 10 CFR Part 50, Appendix B, or their equivalent (as applicable), confirmation process, and administrative controls.
- 9. Administrative Controls: The administrative controls for such programs, including their implementing procedures and review and approval processes, are under existing site 10 CFR 50 Appendix B Quality Assurance Programs, or their equivalent, as applicable. Such a program is thus expected to be established with a sufficient level of documentation and administrative controls to ensure effective long-term implementation.
- 10. Operating Experience: Relatively few incidents of PWR internals aging degradation have been reported in operating U.S. commercial PWR plants. A summary of observations to date is provided in Appendix A of MRP-227-A. The applicant is expected to review subsequent operating experience for impact on its program or to participate in industry initiatives that perform this function.
The application of the MRP-227 guidance will establish a considerable amount of operating experience over the next few years. Section 7 of MRP-227 describes the reporting requirements for these applications, and the plan for evaluating the accumulated additional operating experience.
References 10 CFR Part 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
10 CFR Part 50.55a, Codes and Standards, Office of the Federal Register, National Archives and Records Administration, 2009.
ASME Boiler & Pressure Vessel Code,Section V, Nondestructive Examination, 2004 Edition, American Society of Mechanical Engineers, New York, NY.
December 201 0 XI M16A-7 NUREG-1801, Rev. 2 OAG10001390_00596
ASME Section XI, Rules for In service Inspection of Nuclear Power Plant Components, The ASME Boiler and Pressure Vessel Code, 2004 edition as approved in 10 CFR 50.55a, The American Society of Mechanical Engineers, New York, NY.
B&W Report No. BAW-2248, Demonstration of the Management of Aging Effects for the Reactor Vessel Internals, Framatome Technologies (now AREVA Technologies), Lynchburg VA, July 1997. (NRC Microfiche Accession Number A0076, Microfiche Pages 001 - 108).
EPRI 1014986, PWR Primary Water Chemistry Guidelines, Volume 1, Revision 6, Electric Power Research Institute, Palo Alto, CA, December 2007. (Non-publicly available ADAMS Accession Number ML081140278). The non-proprietary version of the report may accessed by members of the public at ADAMS Accession Number ML081230449 EPRI 1016596, Materials Reliability Program: Pressurized Water Reactor Internals Inspection and Evaluation Guidelines (MRP-227-Rev. 0), Electric Power Research Institute, Palo Alto, CA: 2008.
EPRI 1016609, Materials Reliability Program: Inspection Standard for PWR Internals (MRP-228), Electric Power Research Institute, Palo Alto, CA, July 2009. (Non-publicly available ADAMS Accession Number ML092120574). The non-proprietary version of the report may accessed by members of the public at ADAMS Accession Number ML092750569.
NRC RAI No. 11 in the NRC's Request for Additional Information to the Mr. Christen B. Larson, EPRI MRP on Topical Report MRP-227 dated November 12, 2009.
NRC Safety Evaluation from C. I. Grimes [NRC] to R. A, Newton [Chairman, Westinghouse Owners Group], Acceptance for Referencing of Generic License Renewal Program Topical Report Entitled "License Renewal Evaluation: Aging Management for Reactor Internals,"
WCAP-14577, Revision 1, February 10, 2001. (ADAMS Accession Number ML010430375).
NRC Safety Evaluation from C. I. Grimes [NRC] to W. R. Gray [Framatome Technologies],
Acceptance for Referencing of Generic License Renewal Program Topical Report Entitled "Demonstration of the Management of Aging Effects for the Reactor Vessel Internals, "
February 10, 2001. (ADAMS Accession Number ML993490288).
NUREG-1800, Revision 2, Standard Review Plan for Review of License Renewal Applications for Nuclear Power Plants, Appendix A.1, "Aging Management Review - Generic (Branch Technical Position RLSB-1)," U.S. Nuclear Regulatory Commission, Washington, DC, 2010.
Westinghouse Non-Proprietary Class 3 Report No. WCAP-14577-Rev. 1-A, License Renewal Evaluation: Aging Management for Reactor Internals, Westinghouse Electric Company, Pittsburgh, PA [March 2001]. Report was submitted to the NRC Document Control Desk in a letter dated April 9, 2001. (ADAMS Accession Number ML011080790).
NUREG-1801, Rev. 2 XI M16A-8 December 201 0 OAG10001390_00597
XI. M17 FLOW-ACCELERATED CORROSION Program Description The program relies on implementation of the Electric Power Research Institute (EPRI) guidelines in the Nuclear Safety Analysis Center (NSAC)-202L-R2 or R3 for an effective flow-accelerated corrosion (FAC) program. The program includes performing (a) an analysis to determine critical locations, (b) limited baseline inspections to determine the extent of thinning at these locations, and (c) follow-up inspections to confirm the predictions, or repairing or replacing components as necessary. NSAC-202L-R2 or R3 provides general guidelines for the FAC program. To provide reasonable assurance that all the aging effects caused by FAC are properly managed, the program includes the use of a predictive code, such as CHECWORKS, that uses the implementation guidance of NSAC-202L-R2 or R3 to satisfy the criteria specified in 10 CFR Part 50, Appendix 8, for development of procedures and control of special processes.
Evaluation and Technical Basis
- 1. Scope of Program: The FAC program, described by the EPRI guidelines in NSAC-202L-R2 or R3, includes procedures or administrative controls to assure that the structural integrity of all carbon steel lines containing high-energy fluids (two-phase as well as single-phase) is maintained. Valve bodies retaining pressure in these high-energy systems are also covered by the program. The FAC program was originally outlined in NUREG-1344 and was further described through the Nuclear Regulatory Commission (NRC) Generic Letter 89-08.
- 2. Preventive Actions: The FAC program is an analysis, inspection, and verification program; no preventive action has been recommended in this program. However, it is noted that monitoring of water chemistry to control pH and dissolved oxygen content, and selection of appropriate piping material, geometry, and hydrodynamic conditions, are effective in reducing FAC.
- 3. Parameters Monitored/Inspected: The aging management program monitors the effects of loss of material due to wall thinning on the intended function of piping and components by measuring wall thickness.
- 4. Detection of Aging Effects: Degradation of piping and components occurs by wall thinning.
The inspection program delineated in NSAC-202L-R2 or R3 consists of identification of susceptible locations, as indicated by operating conditions or special considerations.
Ultrasonic or radiographic testing is used to detect wall thinning. A representative sample of components is selected based on the most susceptible locations for wall thickness measurements at a frequency in accordance with NSAC 202L guidelines to ensure that degradation is identified and mitigated before the component integrity is challenged. The extent and schedule of the inspections ensure detection of wall thinning before the loss of intended function.
- 5. Monitoring and Trending: CHECWORKS or a similar predictive code is used to predict component degradation in the systems conducive to FAC, as indicated by specific plant data, including material, hydrodynamic, and operating conditions. CHECWORKS is acceptable because it provides a bounding analysis for FAC. The analysis is bounding because in general the predicted wear rates and component thicknesses are conservative when compared to actual field measurements. It is recognized that CHECWORKS is not December 201 0 XI M17-1 NUREG-1801, Rev. 2 OAG10001390_00598
always conservative in predicting component thickness; therefore, when measurements show the predictions to be non-conservative, the model must be re-calibrated using the latest field data. CHECWORKS was developed and benchmarked by comparing CHECWORKS predictions against actual measured component thickness measurements obtained from many plants. The inspection schedule developed by the licensee on the basis of the results of such a predictive code provides reasonable assurance that structural integrity will be maintained between inspections. Inspection results are evaluated to determine if additional inspections are needed to ensure that the extent of wall thinning is adequately determined, that intended function will not be lost, and that corrective actions are adequately identified. Previous wear rate predictions due to FAC may change after a power uprate is implemented. Wear rates are updated in CHECWORKS according to power uprate conditions. Subsequent field measurements are used to calibrate or benchmark the predicted wear rates.
- 6. Acceptance Criteria: Inspection results are input for a predictive computer code, such as CHECWORKS, to calculate the number of refueling or operating cycles remaining before the component reaches the minimum allowable wall thickness. If calculations indicate that an area will reach the minimum allowed wall thickness before the next scheduled outage, corrective action should be considered.
- 7. Corrective Actions: Prior to service, components for which the acceptance criteria are not satisfied are reevaluated, repaired, or replaced. Long-term corrective actions could include adjusting operating parameters or selecting materials resistant to FAC. When susceptible components are replaced with resistant materials, such as high Cr material, the downstream components should be monitored closely to mitigate any increased wear. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions.
- 8. Confirmation Process: Site quality assurance (QA) procedures, review and approval processes, and administrative controls are implemented in accordance with the requirements of 10 CFR Part 50, Appendix B. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the confirmation process.
- 9. Administrative Controls: Site QA procedures, review and approval processes, and administrative controls are implemented in accordance with the requirements of 10 CFR Part 50, Appendix B. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the administrative controls.
- 10. Operating Experience: Wall-thinning problems in single-phase systems have occurred in feedwater and condensate systems (NRC IE Bulletin No. 87-01; NRC Information Notice [IN]
81-28, IN 92-35, IN 95-11, IN 2006-08) and in two-phase piping in extraction steam lines (NRC IN 89-53, IN 97-84) and moisture separation reheater and feedwater heater drains (NRC IN 89-53, IN 91-18, IN 93-21, IN 97-84). Observed wall thinning may be due to mechanisms other than FAC, which require alternate materials to resolve the issue (Licensee Event Report 50-237/2007-003-00). Operating experience shows that the present program, when properly implemented, is effective in managing FAC in high-energy carbon steel piping and components.
NUREG-1801, Rev. 2 XI M17-2 December 201 0 OAG10001390_00599
References 10 CFR Part 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
10 CFR Part 50.55a, Codes and Standards, Office of the Federal Register, National Archives and Records Administration, 2009.
NRC Generic Letter 89-08, Erosion/Corrosion-Induced Pipe Wall Thinning, U.S. Nuclear Regulatory Commission, May 2, 1989.
NRC IE Bulletin 87-01, Thinning of Pipe Walls in Nuclear Power Plants, U.S. Nuclear Regulatory Commission, July 9, 1987.
NRC Information Notice 89-53, Rupture of Extraction Steam Line on High Pressure Turbine, U.S. Nuclear Regulatory Commission, June 13, 1989.
NRC Information Notice 91-18, High-Energy Piping Failures Caused by Wall Thinning, U.S. Nuclear Regulatory Commission, March 12,1991.
NRC Information Notice 91-18, Supplement 1, High-Energy Piping Failures Caused by Wall Thinning, U.S. Nuclear Regulatory Commission, December 18, 1991.
NRC Information Notice 92-35, Higher than Predicted Erosion/Corrosion in Uniso/able Reactor Coolant Pressure Boundary Piping inside Containment at a Boiling Water Reactor, U.S. Nuclear Regulatory Commission, May 6, 1992.
NRC Information Notice 93-21, Summary of NRC Staff Observations Compiled during Engineering Audits or Inspections of Licensee Erosion/Corrosion Programs, U.S. Nuclear Regulatory Commission, March 25, 1993.
NRC Information Notice 95-11, Failure of Condensate Piping Because of Erosion/Corrosion at a Flow Straightening Oevice, U.S. Nuclear Regulatory Commission, February 24, 1995.
NRC Information Notice 97-84, Rupture in Extraction Steam Piping as a Result of Flow-Accelerated Corrosion, U.S. Nuclear Regulatory Commission, December 11, 1997.
NRC Information Notice 99-19, Rupture of the Shell Side ofa Feedwater Heater at the Point Beach Nuclear Plant, U.S. Nuclear Regulatory Commission, June 23, 1999.
NSAC-202L-R2, Recommendations for an Effective Flow Accelerated Corrosion Program, Electric Power Research Institute, Nuclear Safety Analysis Center, Palo Alto, CA, April 8, 1999.
NSAC-202L-R3, Recommendations for an Effective Flow Accelerated Corrosion Program, (1011838), Electric Power Research Institute, Nuclear Safety Analysis Center, Palo Alto, CA, May 2006.
NUREG-1344, Erosion/Corrosion-Induced Pipe Wall Thinning in U.S. Nuclear Power Plants, P. C. Wu, U.S. Nuclear Regulatory Commission, April 1989.
December 201 0 XI M17-3 NUREG-1801, Rev. 2 OAG10001390_00600
NRC Information Notice 2006-08, Secondary Piping Rupture at the Mihama Power Station in Japan, U.S. Nuclear Regulatory Commission, March 16,2006.
NRC Licensee Event Report 50- 237/2007- 003- 00, Unit 2 High Pressure Coolant Injection System Declared Inoperable, U.S. Nuclear Regulatory Commission, September 24,2007.
NRC Licensee Event Report 1999-003-01, Manual Reactor Trip due to Heater Drain System Pipe Rupture Caused by Flow Accelerated Corrosion, U.S. Nuclear Regulatory Commission, May 1, 2000.
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XI.M18 BOLTING INTEGRITY Program Description The program manages aging of closure bolting for pressure retaining components. The program relies on recommendations for a comprehensive bolting integrity program, as delineated in NUREG-1339, and industry recommendations, as delineated in the following documents:
- NUREG-1339, "Resolution of Generic Safety Issue 29: Bolting Degradation or Failure in Nuclear Power Plants."
- Electric Power Research Institute (EPRI) NP-5769, "Degradation and Failure of Bolting in Nuclear Power Plants" (with the exceptions noted in NUREG-1339 for safety-related bolting).
- EPRI TR-104213, "Bolted Joint Maintenance and Application Guide."
The program generally includes periodic inspection of closure bolting for indication of loss of preload, cracking, and loss of material due to corrosion, rust, etc. The program also includes preventive measures to preclude or minimize loss of preload and cracking.
Aging management program (AMP) XI.M1, "ASME Section Xllnservice Inspection, Subsections IWB, IWC, and IWD," includes inspection of safety-related and non-safety-related closure bolting and supplements this bolting integrity program. AMPs XI.S1, "ASME Section XI, Subsection IWE"; XI.S3, "ASME Section XI, Subsection IWF"; XI.S6, "Structures Monitoring";
XI.S7, "RG 1.127, "Inspection of Water-Control Structures Associated with Nuclear Power Plants"; and XI.M23, "Inspection of Overhead Heavy Load and Light Load (Related to Refueling)
Handling Systems," manage inspection of safety-related and non-safety related structural bolting.
Evaluation and Technical Basis
- 1. Scope of Program: This program manages aging of closure bolting for pressure retaining components within the scope of license renewal, including both safety-related and non-safety-related bolting. This program does not manage aging of reactor head closure stud bolting (AMP XI.M3) or structural bolting (AMPs XI.S1, XI.S3, XI.S6, XI.S7, and XI.M23).
- 2. Preventive Actions: Selection of bolting material and the use of lubricants and sealants is in accordance with the guidelines of EPRI NP-5769 and the additional recommendations of NUREG-1339 to prevent or mitigate degradation and failure of safety-related bolting.
NUREG-1339 takes exception to certain items in EPRI NP-5769 and recommends additional measures with regard to them. Of particular note, use of molybdenum disulfide (MoS2 ) as a lubricant has been shown to be a potential contributor to stress corrosion cracking (SCC) and should not be used. Preventive measures also include using bolting material that has an actual measured yield strength limited to less than 1,034 megapascals (MPa) (150 kilo-pounds per square inch [ksi]). Bolting replacement activities include proper torquing of the bolts and checking for uniformity of the gasket compression after assembly.
Maintenance practices require the application of an appropriate preload based on guidance in EPRI documents, manufacturer recommendations, or engineering evaluation.
December 201 0 XI M18-1 NUREG-1801, Rev. 2 OAG10001390_00602
- 3. Parameters Monitored/Inspected: This program monitors the effects of aging on the intended function of bolting. Specifically, bolting for safety-related pressure retaining components is inspected for leakage, loss of material, cracking, and loss of preload/loss of prestress. Bolting for other pressure retaining components is inspected for signs of leakage.
High strength closure bolting (actual yield strength greater than or equal to 1,034 MPa
[150 ksi]), if used, should be monitored for cracking.
- 4. Detection of Aging Effects: The American Society of Mechanical Engineers (ASME)
Section XI Inservice Inspection, Subsections IWB, IWC, and IWD program implements inspection of Class 1, Class 2, and Class 3 pressure retaining bolting in accordance with requirements of ASME Code Section XI, 12 Tables IWB-2500-1, IWC-2500-1, and IWD-2500-
- 1. These include volumetric and visual (VT-1) examinations, as appropriate. In addition, for both ASME Code class bolting and non-ASME Code class bolting, periodic system walkdowns and inspections (at least once per refueling cycle) ensure detection of leakage at bolted joints before the leakage becomes excessive. Bolting inspections should include consideration of the guidance applicable for pressure boundary bolting in NUREG-1339 and in EPRI NP-5769 and EPRI TR-104213.
Degradation of pressure boundary closure bolting due to crack initiation, loss of preload, or loss of material may result in leakage from the mating surfaces or joint connections of pressure boundary components. Periodic inspection of pressure boundary components for signs of leakage ensures that age-related degradation of closure bolting is detected and corrected before component leakage becomes excessive. Accordingly, pressure retaining bolted connections should be inspected at least once per refueling cycle. The inspections may be performed as part of ASM E Code Section XI leakage tests or as part of other periodic inspection activities, such as system walkdowns or an external surfaces monitoring program.
High strength closure bolting (actual yield strength greater than or equal to 1,034 MPa (150 ksi) may be subject to stress corrosion cracking. For high strength closure bolts (regardless of code classification), volumetric examination in accordance to that of ASME Code Section XI, Table IWB-2500-1, Examination Category B-G-1, should be performed.
- 5. Monitoring and Trending: The inspection schedules of ASME Section XI components are effective and ensure timely detection of applicable aging effects. If a bolting connection for pressure retaining components not covered by ASME Section XI is reported to be leaking, it may be inspected daily or in accordance with the corrective action process. If the leak rate is increasing, more frequent inspections may be warranted.
- 6. Acceptance Criteria: Any indications of aging effects in ASME pressure retaining bolting are evaluated in accordance with Section XI of the ASME Code. For other pressure retaining bolting, indications of aging should be dispositioned in accordance with the corrective action process.
- 7. Corrective Actions: Replacement of ASME pressure retaining bolting is performed in accordance with appropriate requirements of Section XI of the ASME Code, as subject to the additional guidelines and recommendations of EPRI NP-5769. Replacement of other pressure retaining bolting (i.e., non-ASME code class bolting) is performed in accordance with the guidelines and recommendations of EPRI TR-104213. As discussed in the 12 Refer to the GALL Report, Chapter I, for applicability of other editions of the ASME Code,Section XI.
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Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions.
- 8. Confirmation Process: Site quality assurance procedures, review and approval processes, and administrative controls are implemented in accordance with the requirements of 10 CFR Part 50, Appendix B. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the confirmation process and administrative controls.
- 9. Administrative Controls: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the administrative controls.
- 10. Operating Experience: Degradation of threaded bolting and fasteners in closures for the reactor coolant pressure boundary has occurred from boric acid corrosion, SCC, and fatigue loading (U.S. Nuclear Regulatory Commission [NRC] IE Bulletin 82-02, NRC Generic Letter 91-17). SCC has occurred in high strength bolts used for nuclear steam supply system component supports (EPRI NP-5769). The bolting integrity program developed and implemented in accordance with the applicant's docketed responses to NRC communications on bolting events have provided an effective means of ensuring bolting reliability. These programs are documented in EPRI NP-5769 and TR-104213 and represent industry consensus.
Degradation related failures have occurred in downcomer Tee-quencher bolting in boiling water reactors (BWRs) designed with drywells (ADAMS Accession Number ML050730347).
Leakage from bolted connections has been observed in reactor building closed cooling systems of BWRs (LER 50-341/2005-001).
The applicant is to evaluate applicable operating experience to support the conclusion that the effects of aging are adequately managed.
References 10 CFR Part 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
10 CFR 50.55a, Codes and Standards, Office of the Federal Register, National Archives and Records Administration, 2009.
ASME Section XI, Rules for In service Inspection of Nuclear Power Plant Components, The ASME Boiler and Pressure Vessel Code, 2004 edition as approved in 10 CFR 50.55a, The American Society of Mechanical Engineers, New York, NY.
EPRI NP-5769, Oegradation and Failure of Bolting in Nuclear Power Plants, Volumes 1 and 2, Electric Power Research Institute, April 1988.
EPRI TR-104213, Bolted Joint Maintenance & Application Guide, Electric Power Research Institute, December 1995.
NRC Generic Letter 91-17, Generic Safety Issue 79, Bolting Oegradation or Failure in Nuclear Power Plants, U.S. Nuclear Regulatory Commission, October 17, 1991.
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NRC IE Bulletin No. 82-02, Oegradation of Threaded Fasteners in the Reactor Coolant Pressure Boundary of PWR Plants, U.S. Nuclear Regulatory Commission, June 2, 1982.
NRC Morning Report, Failure of Safety/Relief Valve Tee-Quencher Support Bolts, March 14, 2005. (ADAMS Accession Number ML050730347)
N U REG-1339, Resolution of Generic Safety Issue 29: Bolting Oegradation or Failure in Nuclear Power Plants, U.S. Nuclear Regulatory Commission, June 1990.
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XI.M19 STEAM GENERATORS Program Description The Steam Generator program is applicable to managing the aging of steam generator tubes, plugs, sleeves, and secondary side components that are contained within the steam generator (i.e., secondary side internals).
The establishment of a steam generator program for ensuring steam generator tube integrity is required by plant technical specifications. The steam generator tube integrity portion of the technical specifications at each PWR contains the same fundamental requirements as outlined in the standard technical specifications of NUREG-1430, Volume 1, Rev. 3, for Babcock &
Wilcox pressurized water reactors (PWRs); NUREG-1431, Volume 1, Rev. 3, for Westinghouse PWRs; and NUREG-1432, Volume 1, Rev. 3, for Combustion Engineering PWRs. The requirements pertaining to steam generators in these three versions of the standard technical specifications are essentially identical. The technical specifications require tube integrity to be maintained and specify performance criteria, condition monitoring requirements, inspection scope and frequency, acceptance criteria for the plugging or repair of flawed tubes, acceptable tube repair methods, and leakage monitoring requirements.
The nondestructive examination techniques used to inspect tubes, plugs, sleeves, and secondary side internals are intended to identify components (e.g., tubes, plugs) with degradation that may need to be removed from service or repaired.
The Steam Generator program at PWRs is modeled after Nuclear Energy Institute (NEI) 97-06, Revision 2, "Steam Generator Program Guidelines." This program references a number of industry guidelines (e.g., the EPRI PWR Steam Generator Examination Guidelines, PWR Primary-to-Secondary Leak Guidelines, PWR Primary Water Chemistry Guidelines, PWR Secondary Water Chemistry Guidelines, Steam Generator Integrity Assessment Guidelines, Steam Generator In Situ Pressure Test Guidelines) and incorporates a balance of prevention, mitigation, inspection, evaluation, repair, and leakage monitoring measures. The NEI 97-06 document (a) includes performance criteria that are intended to provide assurance that tube integrity is being maintained consistent with the plant's licensing basis and (b) provides guidance for monitoring and maintaining the tubes to provide assurance that the performance criteria are met at all times between scheduled inspections of the tubes. Steam generator tube integrity can be affected by degradation of steam generator plugs, sleeves, and secondary side internals. Therefore, all of these components are addressed by this aging management program (AMP). The NEI 97-06 program has been effective at managing the aging effects associated with steam generator tubes, plugs, sleeves, and secondary side internals.
Evaluation and Technical Basis
- 1. Scope of Program: This program addresses degradation associated with steam generator tubes, plugs, sleeves, and secondary side components that are contained within the steam generator (i.e., secondary side internals). It does not cover degradation associated with the steam generator shell, channelhead, nozzles, or welds associated with these components.
- 2. Preventive Actions: This program includes preventive and mitigative actions for addressing degradation. Preventive and mitigative measures that are part of the Steam Generator program include foreign material exclusion programs, and other primary and secondary side maintenance activities. The program includes foreign material exclusion as a means to December 201 0 XI M19-1 NUREG-1801, Rev. 2 OAG10001390_00606
inhibit wear degradation and secondary side maintenance activities, such as sludge lancing, for removing deposits that may contribute to degradation. Guidance on foreign material exclusion is provided in NEI 97-06. Guidance on maintenance of secondary side integrity is provided in the EPRI Steam Generator Integrity Assessment Guidelines. Primary side preventive maintenance activities include replacing plugs made with corrosion susceptible materials with more corrosion resistant materials and preventively plugging tubes susceptible to degradation.
Extensive deposit buildup in the steam generators could affect tube integrity. The EPRI Steam Generator Integrity Assessment Guidelines, which are referenced in NEI 97-06, provide guidance on maintenance on the secondary side of the steam generator, including secondary side cleaning. Secondary side water chemistry plays an important role in controlling the introduction of impurities into the steam generator and potentially limiting their deposition on the tubes. Maintaining high water purity reduces susceptibility to SCC or IGSCC. Water chemistry is monitored and maintained in accordance with the Water Chemistry program. The program description and evaluation and technical basis of monitoring and maintaining water chemistry are addressed in GALL AMP XI.M2, "Water Chemistry."
- 3. Parameters Monitored/Inspected: There are currently three types of steam generator tubing used in the United States: mill annealed Alloy 600, thermally treated Alloy 600, and thermally treated Alloy 690. Mill annealed Alloy 600 steam generator tubes have experienced degradation due to corrosion (e.g., primary water stress corrosion cracking, outside diameter stress corrosion cracking, intergranular attack, pitting, and wastage) and mechanically induced phenomena (e.g., denting, wear, impingement damage, and fatigue).
Thermally treated Alloy 600 steam generator tubes have experienced degradation due to corrosion (primarily cracking) and mechanically induced phenomena (primarily wear).
Thermally treated Alloy 690 tubes have only experienced tube degradation due to mechanically induced phenomena (primarily wear). Degradation of tube plugs, sleeves, and secondary side internals have also been observed, depending, in part, on the material of construction of the specific component.
The program includes an assessment of the forms of degradation to which a component is susceptible and implementation of inspection techniques capable of detecting those forms of degradation. The parameter monitored is specific to the component and the acceptance criteria for the inspection. For example, the severity of tube degradation may be evaluated in terms of the depth of degradation or measured voltage, dependent on whether a depth-based or voltage-based tube repair criteria (acceptance criteria) is being implemented for that specific degradation mechanism. Other parameters monitored include signals of excessive deposit buildup (e.g., steam generator water level oscillations), which may result in fatigue failure of tubes or corrosion of the tubes; water chemistry parameters, which may indicate unacceptable levels of impurities; primary-to-secondary leakage, which may indicate excessive tube, plug, or sleeve degradation; and the presence of loose parts or foreign objects on the primary and secondary side of the steam generator, which may result in tube damage.
Water chemistry parameters are also monitored as discussed in AMP XI.M2. The EPRI PWR Steam Generator Primary-to-Secondary Leakage Guidelines (EPRI 1008219) provides guidance on monitoring primary-to-secondary leakage. The EPRI Steam Generator Integrity Assessment Guidelines (EPRI 1012987) provide guidance on secondary side activities.
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In summary, the NEI 97-06 program provides guidance on parameters to be monitored or inspected.
- 4. Detection of Aging Effects: The technical specifications require that a Steam Generator program be established and implemented to ensure that steam generator tube integrity is maintained. This requirement ensures that components that could compromise tube integrity are properly evaluated or monitored (e.g., degradation of a secondary side component that could result in a loss of tube integrity is managed by this program). The inspection requirements in the technical specifications are intended to detect degradation (i.e., aging effects), if they should occur.
The technical specifications are performance-based, and the actual scope of the inspection and the expansion of sample inspections are justified based on the results of the inspections. The goal is to perform inspections at a frequency sufficient to provide reasonable assurance of steam generator tube integrity for the period of time between inspections.
The general condition of some components (e.g., plugs and secondary side components) may be monitored visually, and, subsequently, more detailed inspections may be performed if degradation is detected.
NEI 97-06 provides additional guidance on inspection programs to detect degradation of tubes, sleeves, plugs, and secondary side internals. The frequencies of the inspections are based on technical assessments. Guidance on performing these technical assessments is contained in NEI 97-06 and the associated industry guidelines.
The inspections and monitoring are performed by qualified personnel using qualified techniques in accordance with approved licensee procedures. The EPRI PWR Steam Generator Examination Guidelines (EPRI 1013706) contains guidance on the qualification of steam generator tube inspection techniques.
The primary-to-secondary leakage monitoring program provides a potential indicator of a loss of steam generator tube integrity. NEI 97-06 and the associated EPRI guidelines provide information pertaining to an effective leakage monitoring program.
- 5. Monitoring and Trending: Condition monitoring assessments are performed to determine whether the structural- and accident-induced leakage performance criteria were satisfied during the prior operating interval. Operational assessments are performed to verify that structural and leakage integrity will be maintained for the planned operating interval before the next inspection. If tube integrity cannot be maintained for the planned operating interval before the next inspection, corrective actions are taken in accordance with the plant's corrective action program. Comparisons of the results of the condition monitoring assessment to the predictions of the previous operational assessment are performed to evaluate the adequacy of the previous operational assessment methodology. If the operational assessment was not conservative in terms of the number and/or severity of the condition, corrective actions are taken in accordance with the plant's corrective action program.
The technical specifications require condition monitoring and operational assessments to be performed (although the technical specifications do not explicitly require operational assessments, these assessments are necessary to ensure that the tube integrity will be December 201 0 XI M19-3 NUREG-1801, Rev. 2 OAG10001390_00608
maintained until the next inspection). Condition monitoring and operational assessments are done in accordance with the technical specification requirements and guidance in NEI 97-06 and the EPRI Steam Generator Integrity Assessment Guidelines.
The goal of the inspection program for all components covered by this AMP is to ensure that the components continue to function consistent with the design and licensing basis of the facility (including regulatory safety margins).
Assessments of the degradation of steam generator secondary side internals are performed in accordance with the guidance in the EPRI Steam Generator Integrity Assessment Guidelines to ensure the component continues to function consistent with the design and licensing basis and to ensure technical specification requirements are satisfied.
- 6. Acceptance Criteria: Assessment of tube and sleeve integrity and plugging or repair criteria of flawed and sleeved tubes is in accordance with plant technical specifications. The criteria for plugging or repairing steam generator tubes and sleeves are based on U.S.
Nuclear Regulatory Commission (NRC) Regulatory Guide 1.121 and are incorporated into plant technical specifications. Guidance on assessing the acceptability of flaws is also provided in NEI 97-06 and the associated EPRI guidelines, including the EPRI Steam Generator In-Situ Pressure Test Guidelines and EPRI Steam Generator Integrity Assessment Guidelines.
Degraded plugs, degraded secondary side internals, and leaving a loose part or a foreign object in the steam generator are evaluated for continued acceptability on a case-by-case basis. NEI 97-06 and the associated EPRI guidelines provide guidance on the performance of these evaluations. The intent of these evaluations is to ensure that the components affected by parts or objects have adequate integrity consistent with the design and licensing basis of the facility.
Guidance on the acceptability of primary-to-secondary leakage and water chemistry parameters also are discussed in NEI 97-06 and the associated EPRI guidelines.
- 7. Corrective Actions: For degradation of steam generator tubes and sleeves (if applicable),
the technical specifications provide requirements on the actions to be taken when the acceptance criteria are not met. For degradation of other components, the appropriate corrective action is evaluated per NEI 97-06 and the associated EPRI guidelines, the American Society of Mechanical Engineers (ASME) Code Section XI (2004 Edition),13 10 CFR 50.65, and 10 CFR Part 50, Appendix B, as appropriate. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable for ensuring effective corrective actions.
- 8. Confirmation Process: Site quality assurance (QA) procedures, review and approval processes, and site quality assurance procedures, review and approval processes, and administrative controls are implemented in accordance with the requirements of 10 CFR Part 50, Appendix B. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the confirmation process and administrative controls.
13 Refer to the GALL Report, Chapter 1, for applicability of other editions of the ASME Code.
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In addition, the adequacy of the preventive measures in the Steam Generator program is confirmed through periodic inspections.
- 9. Administrative Controls: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the administrative controls.
- 10. Operating Experience: Several generic communications have been issued by the NRC related to the steam generator programs implemented at plants. The reference section lists many of these generic communications. In addition, NEI 97-06 provides guidance to the industry for routinely sharing pertinent steam generator operating experience and for incorporating lessons learned from plant operation into guidelines referenced in NEI 97-06.
The latter includes providing interim guidance to the industry, when needed.
The NEI 97-06 program has been effective at managing the aging effects associated with steam generator tubes, plugs, sleeves, and secondary side components that are contained within the steam generator (i.e., secondary side internals), such that the steam generators can perform their intended safety function.
References 10 CFR Part 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
10 CFR Part 50.55a, Codes and Standards, Office of the Federal Register, National Archives and Records Administration, 2009.
10 CFR 50.65, Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
EPRI 1008219, PWR Primary-to-Secondary Leak Guidelines: Revision 3, Electric Power Research Institute, Palo Alto, CA, December 2004.
EPRI 1012987, Steam Generator Integrity Assessment Guidelines: Revision 2, Electric Power Research Institute, Palo Alto, CA, July 2006.
EPRI 1013706, PWR Steam Generator Examination Guidelines: Revision 7, Electric Power Research Institute, Palo Alto, CA, October 2007.
EPRI 1014983, Steam Generator In-Situ Pressure Test Guidelines: Revision 3, Electric Power Research Institute, Palo Alto, CA, August 2007.
EPRI 1014986, Pressurized Water Reactor Primary Water Chemistry Guidelines: Revision 6, Electric Power Research Institute, Palo Alto, CA, December 2007.
EPRI 1016555, Pressurized Water Reactor Secondary Water Chemistry Guidelines: Revision 7, Electric Power Research Institute, Palo Alto, CA, February 2009.NEI 97-06, Rev. 2, Steam Generator Program Guidelines, Nuclear Energy Institute, September 2005.
NRC Bulletin 88-02, Rapidly Propagating Cracks in Steam Generator Tubes, U.S. Nuclear Regulatory Commission, February 5, 1988.
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NRC Bulletin 89-01, Failure of Westinghouse Steam Generator Tube Mechanical Plugs, U.S.
Nuclear Regulatory Commission, May 15, 1989.
NRC Bulletin 89-01, Supplement 1, Failure of Westinghouse Steam Generator Tube Mechanical Plugs, U.S. Nuclear Regulatory Commission, November 14, 1990.
NRC Bulletin 89-01, Supplement 2, Failure of Westinghouse Steam Generator Tube Mechanical Plugs, U.S. Nuclear Regulatory Commission, June 28, 1991.
NRC Draft Regulatory Guide DG-1074, Steam Generator Tube Integrity, U.S. Nuclear Regulatory Commission, December 1998.
NRC Regulatory Guide, 1.121, Bases for Plugging Degraded PWR Steam Generator Tubes, U.S. Nuclear Regulatory Commission, August 1976.
NRC Generic Letter 95-03, Circumferential Cracking of Steam Generator Tubes, U.S. Nuclear Regulatory Commission, April 28, 1995.
NRC Generic Letter 95-05, Voltage-Based Repair Criteria for Westinghouse Steam Generator Tubes Affected by Outside Diameter Stress Corrosion Cracking, U.S. Nuclear Regulatory Commission, August 3, 1995.
NRC Generic Letter 97-05, Steam Generator Tube Inspection Techniques, U.S. Nuclear Regulatory Commission, December 17, 1997.
NRC Generic Letter 97-06, Degradation of Steam Generator Internals, U.S. Nuclear Regulatory Commission, December 30, 1997.
NRC Generic Letter 2004-01, Requirements for Steam Generator Tube Inspections, U.S.
Nuclear Regulatory Commission, August 30, 2004.
NRC Generic Letter 2006-01, Steam Generator Tube Integrity and Associated Technical Specifications, U.S. Nuclear Regulatory Commission, January 20,2006.
NRC Information Notice 85-37, Chemical Cleaning of Steam Generators at Millstone 2, U.S.
Nuclear Regulatory Commission, May 14, 1985.
NRC Information Notice 88-06, Foreign Objects in Steam Generators, U.S. Nuclear Regulatory Commission, February 29, 1988.
NRC Information Notice 88-99, Detection and Monitoring of Sudden and/or Rapidly Increasing Primary-to-Secondary Leakage, U.S. Nuclear Regulatory Commission, December 20, 1988.
NRC Information Notice 89-65, Potential for Stress Corrosion Cracking in Steam Generator Tube Plugs Supplied by Babcock and Wilcox, U.S. Nuclear Regulatory Commission, September 8, 1989.
NRC Information Notice 90-49, Stress Corrosion Cracking in PWR Steam Generator Tubes, U.S. Nuclear Regulatory Commission, August 6, 1990.
NRC Information Notice 91-19, Steam Generator Feedwater Distribution Piping Damage, US Nuclear Regulatory Commission, March 12, 1991.
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NRC Information Notice 91-43, Recent Incidents Involving Rapid Increases in Primary-to-Secondary Leak Rate, U.S. Nuclear Regulatory Commission, July 5, 1991.
NRC Information Notice 91-67, Problems with the Reliable Detection of Intergranular Attack (IGA) of Steam Generator Tubing, U.S. Nuclear Regulatory Commission, October 21, 1991.
NRC Information Notice 92-80, Operation with Steam Generator Tubes Seriously Degraded, U.S. Nuclear Regulatory Commission, December 7, 1992.
NRC Information Notice 93-52, Draft NUREG-1477, Voltage-Based Interim Plugging Criteria for Steam Generator Tubes, U.S. Nuclear Regulatory Commission, July 14, 1993.
NRC Information Notice 93-56, Weaknesses in Emergency Operating Procedures Found as a Result of Steam Generator Tube Rupture, U.S. Nuclear Regulatory Commission, July 22, 1993.
NRC Information Notice 94-05, Potential Failure of Steam Generator Tubes Sleeved With Kinetically Welded Sleeves, U.S. Nuclear Regulatory Commission, January 19, 1994.
NRC Information Notice 94-43, Determination of Primary-to-Secondary Steam Generator Leak Rate, U.S. Nuclear Regulatory Commission, June 10, 1994.
NRC Information Notice 94-62, Operational Experience on Steam Generator Tube Leaks and Tube Ruptures, U.S. Nuclear Regulatory Commission, August 30, 1994.
NRC Information Notice 94-87, Unanticipated Crack in a Particular Heat of Alloy 600 Used for Westinghouse Mechanical Plugs for Steam Generator Tubes, U.S. Nuclear Regulatory Commission, December 22, 1994.
NRC Information Notice 94-88, Inservice Inspection Deficiencies Result in Severely Degraded Steam Generator Tubes, U.S. Nuclear Regulatory Commission, December 23, 1994.
NRC Information Notice 95-40, Supplemental Information to Generic Letter 95-03, Circumferential Cracking of Steam Generator Tubes, U.S. Nuclear Regulatory Commission, September 20, 1995.
NRC Information Notice 96-09, Damage in Foreign Steam Generator Internals, U.S. Nuclear Regulatory Commission, February 12, 1996.
NRC Information Notice 96-09, Supplement 1, Damage in Foreign Steam Generator Internals, U.S. Nuclear Regulatory Commission, July 10, 1996.
NRC Information Notice 96-38, Results of Steam Generator Tube Examinations, U.S. Nuclear Regulatory Commission, June 21, 1996.
NRC Information Notice 97-26, Degradation in Small-Radius U-Bend Regions of Steam Generator Tubes, U.S. Nuclear Regulatory Commission, May 19, 1997.
NRC Information Notice 97-49, B&W Once-Through Steam Generator Tube Inspection Findings, U.S. Nuclear Regulatory Commission, July 10, 1997.
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NRC Information Notice 97-79, Potential Inconsistency in the Assessment of the Radiological Consequences of a Main Steam Line Break Associated with the Implementation of Steam Generator Tube Voltage-Based Repair Criteria, U.S. Nuclear Regulatory Commission, November 20, 1997.
NRC Information Notice 97-88, Experiences During Recent Steam Generator Inspections, U.S.
Nuclear Regulatory Commission, December 16, 1997.
NRC Information Notice 98-27, Steam Generator Tube End Cracking, U.S. Nuclear Regulatory Commission, July 24, 1998.
NRC Information Notice 2000-09, Steam Generator Tube Failure at Indian Point Unit 2, U.S.
Nuclear Regulatory Commission, June 28, 2000.
NRC Information Notice 2001-16, Recent Foreign and Domestic Experience with Degradation of Steam Generator Tubes and Internals, U.S. Nuclear Regulatory Commission, October 31, 2001.
NRC Information Notice 2002-02, Recent Experience with Plugged Steam Generator Tubes, U.S. Nuclear Regulatory Commission, January 8,2002.
NRC Information Notice 2002-02, Supplement 1, Recent Experience with Plugged Steam Generator Tubes, U.S. Nuclear Regulatory Commission, July 17, 2002.
NRC Information Notice 2002-21, Axial Outside-Diameter Cracking Affecting Thermally Treated Alloy 600 Steam Generator Tubing, U.S. Nuclear Regulatory Commission, June 25,2002.
NRC Information Notice 2002-21, Supplement 1, Axial Outside-Diameter Cracking Affecting Thermally Treated Alloy 600 Steam Generator Tubing, U.S. Nuclear Regulatory Commission, April 1, 2003.
NRC Information Notice 2003-05, Failure to Detect Freespan Cracks in PWR Steam Generator Tubes, U.S. Nuclear Regulatory Commission, June 5,2003.
NRC Information Notice 2003-13, Steam Generator Tube Degradation at Diablo Canyon, U.S.
Nuclear Regulatory Commission, August 28, 2003.
NRC Information Notice 2004-10, Loose Parts in Steam Generators, U.S. Nuclear Regulatory Commission, May 4, 2004.
NRC Information Notice 2004-16, Tube Leakage Due to a Fabrication Flaw in a Replacement Steam Generator, U.S. Nuclear Regulatory Commission, August 3,2004.
NRC Information Notice 2004-17, Loose Part Detection and Computerized Eddy Current Data Analysis in Steam Generators, U.S. Nuclear Regulatory Commission, August 25,2004.
NRC Information Notice 2005-09, Indications in Thermally Treated Alloy 600 Steam Generator Tubes and Tube-to- Tubesheet Welds, U.S. Nuclear Regulatory Commission, April 7, 2005.
NRC Information Notice 2005-29, Steam Generator Tube and Support Configuration, U.S.
Nuclear Regulatory Commission, October 27, 2005.
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NRC Information Notice 2007-37, Buildup of Deposits in Steam Generators, U.S. Nuclear Regulatory Commission, November 23, 2007.
NRC Information Notice 2008-07, Cracking Indications in Thermally Treated Alloy 600 Steam Generator Tubes, U.S. Nuclear Regulatory Commission, April 24,2008.
NRC Information Notice 2010-05, Management of Steam Generator Loose Parts and Automated Eddy Current Data Analysis, U.S. Nuclear Regulatory Commission, February 3, 2010.
NRC Regulatory Issue Summary 2000-22, Issues Stemming from NRC Staff Review of Recent Difficulties Experienced in Maintaining Steam Generator Tube Integrity, U.S. Nuclear Regulatory Commission, November 3, 2000.
NRC Regulatory Issue Summary 2007-20, Implementation of Primary-to-Secondary Leakage Performance Criteria, U.S. Nuclear Regulatory Commission, August 23,2007.
NRC Regulatory Issue Summary 2009-04, Steam Generator Tube Inspection Requirements, U.S. Nuclear Regulatory Commission, April 3, 2009.
NUREG-1430, Volume 1, Rev. 3, Standard Technical Specifications for Babcock and Wilcox Pressurized Water Reactors, U.S. Nuclear Regulatory Commission, December 2005.
NUREG-1431, Volume 1, Rev. 3, Standard Technical Specifications for Westinghouse Pressurized Water Reactors, U.S. Nuclear Regulatory Commission, December 2005.
NUREG-1432, Volume 1, Rev. 3, Standard Technical Specifications for Combustion Engineering Pressurized Water Reactors, U.S. Nuclear Regulatory Commission, December 2005.
December 201 0 XI M19-9 NUREG-1801, Rev. 2 OAG10001390_00614
XI.M20 OPEN-CYCLE COOLING WATER SYSTEM Program Description The program relies on implementation of the recommendations of the Nuclear Regulatory Commission (NRC) Generic Letter (GL) 89-13 to ensure that the effects of aging on the open-cycle cooling water (OCCW) (or service water) system will be managed for the period of extended operation. NRC GL 89-13 defines the OCCW system as a system or systems that transfer heat from safety-related structures, systems, and components (SSCs) to the ultimate heat sink (UHS). The guidelines of NRC GL 89-13 for managing an OCCW include (a) surveillance and control of biofouling (see Chapter IX of NUREG-1801); (b) a test program to verify heat transfer capabilities; (c) routine inspection and a maintenance program to ensure that corrosion, erosion, protective coating failure, sediment deposition (silting), and biofouling cannot degrade the performance of safety-related systems serviced by OCCW; (d) a system walkdown inspection to ensure compliance with the licensing basis; and (e) a review of maintenance, operating, and training practices and procedures.
In accordance with guidance of NRC GL 89-13, the OCCW aging management program manages aging effects of components in raw water systems, such as the service water or river water, by using a combination of preventive, condition, and performance monitoring activities.
These include (a) surveillance and control techniques to manage aging effects caused by biofouling, corrosion, erosion, protective coating failures, and silting in the OCCW system or structures and components serviced by the OCCW system; (b) inspection of critical components for signs of corrosion, erosion, and biofouling; and (c) testing of the heat transfer capability of heat exchangers that remove heat from components important to safety.
For buried OCCW piping, the aging effects on the external surfaces are managed by XI.M41, but the internal surfaces are managed by this program. The aging management of closed-cycle cooling water (CCCW) systems is described in XI.M21A, "Closed Treated Water Systems," and is not included as part of this program. The OCCW System program applies to components constructed of various materials, including steel, stainless steel, aluminum, copper alloys, titanium, polymeric materials, and concrete. Piping may be lined with internal coatings or unlined.
Evaluation and Technical Basis
- 1. Scope of Program: The program addresses the aging effects of material loss and fouling due to micro- or macro-organisms and various corrosion mechanisms generally found in OCCW systems and OCCW steel piping components with or without protective coating as described in the applicant's response to NRC GL 89-13. OCCW systems, as defined by NRC GL 89-13, include the service water system and any other cooling system exposed to raw water that transfers heat from safety-related SSCs to the UHS. The OCCW System program applies to components constructed of various materials, including steel, stainless steel, aluminum, copper alloys, titanium, polymeric materials, and concrete. Piping may be lined with internal coatings or unlined.
- 2. Preventive Actions: Preventive actions begin with the use of appropriate material for construction. Steel piping system components are typically lined or coated to protect the underlying metal surfaces from exposure to corrosive cooling water environments.
Implementation of NRC GL 89-13 includes control or preventive measures, such as chemical treatment whenever the potential for biological fouling exists or flushing of December 201 0 XI M20-1 NUREG-1801, Rev. 2 OAGI0001390_00615
infrequently used systems. Treatment with chemicals mitigates microbiologically-influenced corrosion (MIC) and buildup of macroscopic biological fouling debris from biota, such as blue mussels, oysters, or clams. Periodic flushing of the system removes accumulations of biofouling agents, corrosion products, and debris or silt.
- 3. Parameters Monitored/Inspected: This program manages the aging effects, such as loss of heat transfer capability, loss of material, and corrosion effects. Adverse effects on system or component performance are caused by accumulations of biofouling agents, corrosion products, and silt. Cleanliness and material integrity of piping, components, heat exchangers, elastomers, and their internal linings or coatings (when applicable) that are part of the OCCW system or that are cooled by the OCCW system are periodically inspected, monitored, or tested to ensure their heat transfer capabilities. The program ensures (a) removal of accumulations of biofouling agents, corrosion products, and silt and (b) detection of defective protective coatings and corroded OCCW system piping and components that could adversely affect performance of their intended safety functions.
- 4. Detection of Aging Effects: Inspection scope, methods (e.g., visual or nondestructive examination), and testing frequencies are in accordance with the applicant's docketed response to NRC GL 89-13. Inspections for biofouling, damaged coatings, and degraded material condition are conducted. Visual inspections are typically performed to determine whether corrosion, erosion, or biofouling are occurring in the system. Examinations of polymeric materials should be consistent with the examinations described in AMP XI.M38.
Nondestructive testing, such as ultrasonic testing and eddy current testing, are effective methods to measure surface conditions or the extent of wall thinning associated with the service water system piping and components.
- 5. Monitoring and Trending: Heat transfer testing results are documented in plant test procedures and are trended in accordance with the applicant's docketed response to NRC GL 89-13. If corrosion buildup or fouling is noted, the system also is evaluated for their impact on the heat transfer capability of the system. Evidence of corrosion in these systems also is evaluated for its potential impact on the integrity of the piping. For relevant indications, inspections or nondestructive testing is used to determine the extent of biofouling, the condition of the surface coating, the magnitude of localized pitting, and the amount of M IC, if applicable.
- 6. Acceptance Criteria: The acceptance criteria are in accordance with the applicant's docketed response to NRC GL 89-13. Corrosion, erosion, and biofouling can cause significant loss of material in components. Inspected components should exhibit adequate design margin regarding design dimensions (e.g., minimum required wall thickness). As applicable, coatings or linings should be intact to protect the underlying metal. Heat removal capability is within allowable values for the system and components tested, in accordance with NRC GL 89-13.
- 7. Corrective Actions: Evaluations are performed for test or inspection results that do not satisfy established acceptance criteria, and a problem or condition report is initiated to document the concern in accordance with plant administrative procedures. The corrective actions program ensures that the conditions adverse to quality are promptly corrected. If the deficiency is assessed to be significantly adverse to quality, the cause of the condition is determined, and an action plan is developed to preclude repetition. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the corrective actions.
NUREG-1801, Rev. 2 XI M20-2 December 201 0 OAG10001390_00616
- 8. Confirmation Process: Site quality assurance procedures, review and approval processes, and administrative controls are implemented in accordance with the requirements of 10 CFR Part 50, Appendix B. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the confirmation process controls.
- 9. Administrative Controls: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the administrative controls.
failure of protective coatings (NRC IN 85-24), and fouling (NRC IN 81-21, IN 86-96, IN 07-04, IN 07-28) have been observed in a number of heat exchangers. The guidance of NRC GL 89-13 has been implemented for more than 20 years and has been effective in managing aging effects due to biofouling, corrosion, erosion, protective coating failures, and silting in structures and components serviced by OCCW systems.
References 10 CFR Part 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
EPRI 1016555, PWR Secondary Water Chemistry Guidelines-Revision 7, Electric Power Research Institute, Palo Alto, CA, February 2009.
EPRI 1014986, PWR Primary Water Chemistry Guidelines-Revision 6, Volumes 1 and 2, Electric Power Research Institute, Palo Alto, CA, December 2007.
NRC Generic Letter 89-13, Service Water System Problems Affecting Safety-Related Components, U.S. Nuclear Regulatory Commission, July 18, 1989.
NRC Generic Letter 89-13, Supplement 1, Service Water System Problems Affecting Safety-Related Components, U.S. Nuclear Regulatory Commission, April 4, 1990.
NRC Information Notice 81-21, Potential Loss of Direct Access to Ultimate Heat Sink, U.S. Nuclear Regulatory Commission, July 21,1981.
NRC Information Notice 85-24, Failures of Protective Coatings in Pipes and Heat Exchangers, U.S. Nuclear Regulatory Commission, March 26, 1985.
NRC Information Notice 85-30, Microbiologically Induced Corrosion of Containment Service Water System, U.S. Nuclear Regulatory Commission, April 19, 1985.
NRC Information Notice 86-96, Heat Exchanger Fouling Can Cause Inadequate Operability of Service Water Systems, U.S. Nuclear Regulatory Commission, November 20, 1986.
NRC Information Notice 2004-07, Plugging of Safety Injection Pump Lubrication Oil Coolers With Lakeweed, U.S. Nuclear Regulatory Commission, April 7, 2004.
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NRC Information Notice 2007-28, Potential Common Cause Vulnerabilities in Essential Service Water Systems Due to Inadequate Chemistry Controls, U.S. Nuclear Regulatory Commission, September 17, 2007.
NRC Information Notice 2007-06, Potential Common Cause Vulnerabilities in Essential Service Water Systems, U.S. Nuclear Regulatory Commission, February 9, 2007.
NUREG-1915, Safety Evaluation Report Related to the License Renewal of Wolf Creek Generating Station, U.S. Nuclear Regulatory Commission, October 2008.
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XI.M21A CLOSED TREATED WATER SYSTEMS Program Description Nuclear power plants contain many closed, treated water systems. These systems undergo water treatment to control water chemistry and prevent corrosion (i.e., treated water systems).
These systems are also recirculating systems in which the rate of recirculation is much higher than the rate of addition of makeup water (i.e., closed systems). The program includes (a) water treatment, including the use of corrosion inhibitors, to modify the chemical composition of the water such that the function of the equipment is maintained and such that the effects of corrosion are minimized; (b) chemical testing of the water to ensure that the water treatment program maintains the water chemistry within acceptable guidelines; and (c) inspections to determine the presence or extent of corrosion and/or cracking. Depending on the industry standard selected for use in association with this aging management program (AMP) and/or plant operating experience, this program also may include corrosion monitoring (e.g., corrosion coupon testing) and microbiological testing.
Evaluation and Technical Basis
- 1. Scope of Program: This program manages the aging effects of reduction of heat transfer due to fouling, or the loss of material from and cracking due to corrosion and/or stress corrosion cracking of the internal surfaces of piping, piping components, and piping elements fabricated from any material and exposed to treated water. Not included are those piping systems that are managed by another AMP. Examples of systems managed by this AMP include closed-cycle cooling water systems (as defined by U.S. Nuclear Regulatory Commission [NRC] Generic Letter [GL] 89-13 14); closed portions of heating, ventilation, and air conditioning systems; diesel generator cooling water; and auxiliary boiler systems.
Examples of systems not addressed by this AMP include boiling water reactor (BWR) coolant, pressurized water reactor (PWR) primary and secondary water, and PWR/BWR condensate systems. Aging in these systems is managed by the water chemistry AMP (XI.M2) and American Society of Mechanical Engineers (ASME)Section XI, Inservice Inspection, Subsections IWB, IWC, and IWD AMP (XI.M1). Treated fire water systems, if present, are also not included in this AMP. The water used in systems covered by this AMP may, but need not, be demineralized. The water used in systems covered by this AMP receives chemical treatment, including corrosion inhibitors. Untreated water systems are addressed using other AMPs, such as Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components (XI.M38).
- 2. Preventive Actions: This program mitigates aging effects of loss of material and cracking that are due to corrosion and stress corrosion cracking through water treatment. The water treatment program includes corrosion inhibitors and is designed to maintain the function of associated equipment and minimize the corrosivity of the water.
- 3. Parameters Monitored/Inspected: This program monitors water chemistry (preventive monitoring) and the visual appearance of surfaces exposed to the water (condition monitoring). Depending on the industry standard selected for use in association with this 14 NRC GL 89-13 defines a service water system as "the system or systems that transfer heat from safety-related structures, systems, or components to the ultimate heat sink." NRC GL 89-13 further defines a closed-cycle system as a part of the service water system that is not subject to significant sources of contamination, one in which water chemistry is controlled and in which heat is not directly rejected to an ultimate heat sink.
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AMP and/or plant operating experience, this program may also include corrosion monitoring (e.g., corrosion coupon testing) and microbiological testing. These parameters (such as the concentration of iron, copper, silica, oxygen; and hardness, alkalinity, specific conductivity, and pH) are monitored because maintenance of optimal water chemistry prevents loss of material and cracking due to corrosion and stress corrosion cracking. In addition, the visual appearance of surfaces provides evidence of the existence of loss of material or cracking.
The specific water chemistry parameters monitored and the acceptable range of values for these parameters are in accordance with industry standard guidance documents produced by the Electric Power Research Institute (EPRI), the American Society of Heating Refrigeration and Air-Conditioning Engineers, the Cooling Technology Institute, the American Boiler Manufacturer's Association, ASTM standards, water chemistry guidelines recommended by the equipment manufacturer, Nalco Water Handbook, or the ASME. For closed-cycle cooling water systems as defined in NRC GL 89-13, EPRI 1007820 is used.
For other systems, the applicant selects an appropriate industry standard document. In all cases, the selected industry standard guidance document is used in its entirety for the water chemistry control or guidance.
- 4. Detection of Aging Effects: In this program, aging effects are detected through water testing and periodic inspections. Water testing ensures that the water treatment program is effective in maintaining acceptable water chemistry. Water testing is conducted in accordance with the selected industry standard. The frequency of water testing is in accordance with the selected industry standard, but in no case should the testing interval be greater than quarterly unless justified with an additional analysis. Because the control of water chemistry may not be fully effective in mitigating the aging effects, visual inspections are conducted. Inspections are conducted whenever the system boundary is opened.
Additionally, a representative sample of piping and components is selected based on likelihood of corrosion or cracking and inspected at an interval not to exceed once in 10 years. When required by the ASME Code, inspections are conducted in accordance with the applicable code requirements. In the absence of Code inspection requirements, inspections are conducted in accordance with the selected industry standard. In the event that the selected industry standard does not contain inspection requirements, plant-specific inspection and personnel qualification procedures that are capable of detecting corrosion or cracking may be used. If visual examination identifies adverse conditions, additional examinations, including ultrasonic testing, are conducted. Plant operating experience and/or the industry standard program selected for use in association with this AMP may recommend corrosion testing and/or microbiological testing. If warranted, these tests are conducted in accordance with the industry standard selected or other industry standards appropriate for the conduct of corrosion or microbiological testing.
- 5. Monitoring and Trending: Water chemistry data are evaluated against the standards contained in the selected industry standard documents. These data are trended with time, so corrective actions are taken, based on trends in water chemistry, prior to loss of intended function. Inspection results also are trended with time so that the progression of any corrosion or cracking can be evaluated and predicted.
- 6. Acceptance Criteria: Water chemistry concentrations are maintained within the limits specified in the selected industry standard documents. System components should meet system design requirements, such as minimum wall thickness.
- 7. Corrective Actions: Water chemistry concentrations that are not in accordance with the selected industry standard document should be returned to an "in specification" condition in NUREG-1801, Rev. 2 XI M21A-2 December 201 0 OAG10001390_00620
accordance with the referenced guidelines. Some industry standard documents have time guidelines which govern how rapidly "out of specification" conditions should be corrected. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address corrective actions.
- 8. Confirmation Process: Site quality assurance procedures, review and approval processes, and administrative controls are implemented in accordance with the requirements of 10 CFR Part 50, Appendix B. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the confirmation process and administrative controls.
- 9. Administrative Controls: As discussed in the Generic Aging Lessons Learned (GALL)
Report, the staff finds the requirements 10 CFR Part 50, Appendix B, acceptable to address the administrative controls.
- 10. Operating Experience: Degradation of closed-cycle cooling water systems due to corrosion product buildup (NRC Licensee Event Report [LER] 50-327/93-029-00) or through-wall cracks in supply lines (NRC LER 50-280/91-019-00) has been observed in operating plants.
Accordingly, operating experience demonstrates the need for this program.
References 10 CFR Part 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
EPRI 1007820, Closed Cooling Water Chemistry Guideline, Electric Power Research Institute, Palo Alto, CA, April 2004.
Flynn, Daniel. The Nalco Water Handbook, Nalco Company, 2009.
NRC Generic Letter 89-13, Service Water System Problems Affecting Safety-Related Components, U.S. Nuclear Regulatory Commission, July 18, 1989.
NRC Generic Letter 89-13, Supplement 1, Service Water System Problems Affecting Safety-Related Components, U.S. Nuclear Regulatory Commission, April 4, 1990.
NRC Licensee Event Report 50-280/91-019-00, Loss of Containment Integrity due to Crack in Component Cooling Water Piping, October 26, 1991.
NRC Licensee Event Report 50-327/93-029-00, Inoperable Check Valve in the Component Cooling System as a Result of a Build-Up of Corrosion Products between Valve Components, December 13, 1993.
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XI.M22 BORAFLEX MONITORING Program Description For Boraflex panels in spent fuel storage racks, gamma irradiation and long-term exposure to the wet fuel pool environment causes shrinkage resulting in gap formation, gradual degradation of the polymer matrix, and the release of silica to the spent fuel storage pool water. This results in the loss of boron carbide in the neutron absorber sheets. A monitoring program for the Boraflex panels in the spent fuel storage racks is implemented to assure that no unexpected degradation of the Boraflex material compromises the criticality analysis in support of the design of spent fuel storage racks. This aging management program (AMP) relies on periodic inspection, testing, monitoring, and analysis of the criticality design to assure that the required 5% subcriticality margin is maintained. Therefore, this AMP includes: (a) completing sampling and analysis for silica levels in the spent fuel pool water on a regular basis, such as monthly, quarterly, or annually (depending on Boraflex panel condition), and trending the results by using the EPRI RACKLIFE predictive code or its equivalent; and (b) performing neutron attenuation testing or blackness testing to determine gap formation in Boraflex panels or measuring boron areal density by techniques such as the BADGER device.
Evaluation and Technical Basis
- 1. Scope of Program: This program manages the effect of reduction in neutron-absorbing capacity due to degradation in sheets of neutron-absorbing material made of Boraflex affixed to spent fuel racks.
- 2. Preventive Actions: This program is a performance monitoring program and does not include preventive actions.
- 3. Parameters Monitored/Inspected: The parameters monitored include physical conditions of the Boraflex panels, such as gap formation and decreased boron areal density, and the concentration of the silica in the spent fuel pool. These are conditions directly related to degradation of the Boraflex material. When Boraflex is subjected to gamma radiation and long-term exposure to the spent fuel pool environment, the silicon polymer matrix becomes degraded and silica filler and boron carbide are released into the spent fuel pool water. As indicated in the Nuclear Regulatory Commission (NRC) Information Notice (IN) 95-38 and NRC Generic Letter (GL) 96-04, the loss of boron carbide (washout) from Boraflex is characterized by slow dissolution of silica from the surface of the Boraflex and a gradual thinning of the material. Because Boraflex contains about 25% silica, 25% polydimethyl siloxane polymer, and 50% boron carbide, sampling and analysis of the presence of silica in the spent fuel pool provide an indication of depletion of boron carbide from Boraflex; however, the degree to which Boraflex has degraded is ascertained through measurement of the boron areal density.
- 4. Detection of Aging Effects: Aging effects on Boraflex panels are detected by monitoring silica levels in the spent fuel storage pool on a regular basis, such as monthly, quarterly, or annually (depending on Boraflex panel condition); by performing blackness testing to measure gap formation or measuring boron areal density on a frequency determined by the material condition of the Boraflex panels, with a minimum frequency of once every 5 years; and by applying predictive methods to the measured results. The amount of boron carbide present in the Boraflex panels is determined through direct measurement of boron areal density by blackness testing or by periodic verification of boron loss through areal density December 201 0 XI M22-1 NUREG-1801, Rev. 2 OAG10001390_00622
measurement techniques, such as the BADGER device. Frequent Boraflex testing is sufficient to ensure that Boraflex panel degradation does not compromise criticality analysis for the spent fuel pool storage racks. Additionally, changes in the level of silica present in the spent fuel pool water provide an indication of changes in the rate of degradation of Boraflex panels.
- 5. Monitoring and Trending: The periodic inspection measurements and analysis are compared to values of previous measurements and analysis providing a continuing level of data for trend analysis. Sampling and analysis for silica levels in the spent fuel pool water is performed on a regular basis, such as monthly, quarterly, or annually (depending on Boraflex panel condition), and results are trended using the EPRI RACKLIFE predictive code or its equivalent. The frequency to perform blackness testing will be determined by the material condition of the Boraflex panels, with a maximum of 5 years.
- 6. Acceptance Criteria: The 5% subcriticality margin of the spent fuel racks is maintained for the period of extended operation.
- 7. Corrective Actions: Corrective actions are initiated if the test results find that the 5%
subcriticality margin cannot be maintained because of the current or projected future degradation. Corrective actions consist of providing additional neutron-absorbing capacity by Boral or boron steel inserts or other options which are available to maintain a subcriticality margin of 5%. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions.
- 8. Confirmation Process: Site quality assurance procedures, site review and approval processes, and administrative controls are implemented in accordance with the requirements of 10 CFR Part 50, Appendix B. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the confirmation process and administrative controls.
- 9. Administrative Controls: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the administrative controls.
- 10. Operating Experience: NRC IN 87-43 addresses the problems of development of tears and gaps (average 1-2 inches, with the largest 4 inches) in Boraflex sheets due to gamma radiation-induced shrinkage of the material. NRC IN 93-70, NRC IN 95-38, and NRC GL 96-04 address several cases of significant degradation of Boraflex test coupons due to accelerated dissolution of Boraflex caused by pool water flow through panel enclosures and high accumulated gamma dose. Two spent fuel rack cells with about 12 years of service have only 40% of the Boraflex remaining. In such cases, the Boraflex may be replaced by boron steel inserts or by a completely new rack system using Boral. Experience with boron steel is limited; however, the application of Boral for use in the spent fuel storage racks predates the manufacturing and use of Boraflex. The experience with Boraflex panels indicates that coupon surveillance programs are not reliable. Therefore, during the period of extended operation, the measurement of boron areal density correlated, through a predictive code, with silica levels in the pool water, is verified. These monitoring programs provide assurance that degradation of Boraflex sheets is monitored so that appropriate actions can be taken in a timely manner if significant loss of neutron-absorbing capability is occurring.
These monitoring programs provide reasonable assurance that the Boraflex sheets maintain their integrity and are effective in performing their intended function.
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References 10 CFR Part 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
BNL-NUREG-25582, Corrosion Considerations in the Use of Boral in Spent Fuel Storage Pool Racks, January 1979.
EPRI NP-6159, An Assessment of Boraflex Performance in Spent-Nuclear-Fuel Storage Racks, Electric Power Research Institute, Palo Alto, CA, December 14, 1988.
EPRI 1003413, Guidance and Recommended Procedure for Maintaining and Using RACKLIFE Version 1.10, Electric Power Research Institute, Palo Alto, CA, April 2002.
EPRI TR-101986, Boraflex Test Results and Evaluation, Electric Power Research Institute, Palo Alto, CA, March 1, 1993.
EPRI TR-103300, Guidelines for Boraflex Use in Spent-Fuel Storage Racks, Electric Power Research Institute, Palo Alto, CA, December 1, 1993.
NRC Generic Letter 96-04, Boraflex Degradation in Spent Fuel Pool Storage Racks, U.S. Nuclear Regulatory Commission, June 26, 1996.
NRC Information Notice 87-43, Gaps in Neutron Absorbing Material in High Density Spent Fuel Storage Racks, U.S. Nuclear Regulatory Commission, September 8, 1987.
NRC Information Notice 93-70, Degradation of Boraflex Neutron Absorber Coupons, U.S. Nuclear Regulatory Commission, September 10, 1993.
NRC Information Notice 95-38, Degradation of Boraflex Neutron Absorber in Spent Fuel Storage Racks, U.S. Nuclear Regulatory Commission, September 8, 1995.
NRC Regulatory Guide 1.26, Rev. 3, Quality Group Classifications and Standards for Water, Steam, and Radioactive-Waste-Containing Components of Nuclear Power Plants (for Comment), U.S. Nuclear Regulatory Commission, February 1976.
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XI.M23 INSPECTION OF OVERHEAD HEAVY LOAD AND LIGHT LOAD (RELATED TO REFUELING) HANDLING SYSTEMS Program Description Most commercial nuclear facilities have between 50 and 100 cranes. Many are industrial grade cranes, which meet the requirements of 29 CFR Volume XVII, Part 1910, and Section 1910.179.
Most are not within the scope of 10 CFR 54.4 and therefore are not required to be part of the integrated plant assessment. Because only a few cranes operate over safety-related equipment, normally fewer than 10 cranes fall within the scope of 10 CFR 54.4.
Many of the systems and components of these cranes perform an intended function with moving parts or with a change in configuration or are subject to replacement based on qualified life. In these instances, these types of crane systems and components are not within the scope of this aging management program. This program is primarily concerned with structural components that make up the bridge and trolley. NUREG-0612, "Control of Heavy Loads at Nuclear Power Plants," provides specific guidance on the control of overhead heavy load cranes. The aging management activities specified in this program utilize the guidance provided in American Society of Mechanical Engineers (ASME) Safety Standard B30.2, "Overhead and Gantry Cranes (Top Running Bridge, Single or Multiple Girder, Top Running Trolley Hoist)."
Evaluation and Technical Basis
- 1. Scope of Program: The program manages (a) the effects of loss of material due to general corrosion on the bridge rails, bridge, and trolley structural components for those cranes that are within the scope of 10 CFR 54.4 and (b) the effects of wear on the rails in the rail system. The program also manages the effects of loss of preload of bolted connections.
- 2. Preventive Actions: This program is a condition monitoring program. No preventive actions are identified.
- 3. Parameters Monitored/Inspected: Surface condition is monitored by visual inspection to ensure that loss of material is not occurring due to corrosion or wear. Bolted connections are monitored for loose bolts, missing or loose nuts, and other conditions indicative of loss of preload.
- 4. Detection of Aging Effect: Crane rails and structural components are visually inspected at a frequency in accordance ASME B30.2, "Overhead and Gantry Cranes (Top Running Bridge, Single or Multiple Girder, Top Running Trolley Hoist)," or other appropriate standard in the ASME B30 series. For systems that are infrequently in service, such as containment polar cranes, periodic inspections are performed once every refueling cycle just prior to use.
Bolted connections are visually inspected for loose bolts or missing nuts at the same frequency as crane rails and structural components.
- 5. Monitoring and Trending: Visual inspection activities are performed by personnel qualified in accordance with controlled procedures and processes. Deficiencies are documented using applicant-approved processes and procedures, such that results can be trended; however, the program does not include formal trending.
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- 6. Acceptance Criteria: Any visual indication of loss of material due to corrosion or wear and any visual sign of loss of bolting pre-load is evaluated according to ASME 830.2 or other applicable industry standard in the ASME 830 series.
- 7. Corrective Actions: Repairs are performed as specified in ASME 830.2 or other appropriate standard in the ASME 830 series. Site corrective actions program, quality assurance (QA) procedures, site review and approval process, and administrative controls are implemented in accordance with the requirements of 10 CFR Part 50, Appendix 8. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the corrective actions, confirmation process, and administrative controls.
- 8. Confirmation Process: Site QA procedures, review and approval processes, and administrative controls are implemented in accordance with the requirements of 10 CFR Part 50, Appendix 8. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the confirmation process and administrative controls.
- 9. Administrative Controls: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the administrative controls.
- 10. Operating Experience: There has been no history of corrosion-related degradation that threatened the ability of a crane to perform its intended function. Likewise, because cranes have not been operated beyond their design lifetime, there have been no significant fatigue-related structural failures. Operating experience indicates that loss of bolt preload has occurred, but not to the extent that it has threatened the ability of a crane structure to perform its intended function.
References 10 CFR Part 50, Appendix 8, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
10 CFR 54.4, Scope, Office of the Federal Register, National Archives and Records Administration, 2009.
ASME Safety Standard 830.2, Overhead and Gantry Cranes (Top Running Bridge, Single or Multiple Girder, Top Running Trolley Hoist), American Society of Mechanical Engineers, 2005.
NRC Generic Letter 80-113, Control of Heavy Loads, U.S. Nuclear Regulatory Commission, December 22, 1980.
NRC Generic Letter 81-07, Control of Heavy Loads, U.S. Nuclear Regulatory Commission, February 3,1981.
NRC Regulatory Guide 1.160, Rev. 2, Monitoring the Effectiveness of Maintenance at Nuclear Power Plants, U.S. Nuclear Regulatory Commission, March 1997.
NUREG-1801, Rev. 2 XI M23-2 December 2010 OAG10001390_00626
NUREG-0612, Control of Heavy Loads at Nuclear Power Plants, U.S. Nuclear Regulatory Commission, 1980.
December 201 0 XI M23-3 NUREG-1801, Rev. 2 OAG10001390_00627
XI.M24 COMPRESSED AIR MONITORING Program Description The purpose of the compressed air monitoring program is to provide reasonable assurance of the integrity of the compressed air system. The program consists of monitoring moisture content, corrosion, and performance of the compressed air system. This includes (a) preventive monitoring of water (moisture) and other potential contaminants to keep within the specified limits; and (b) inspection of components for indications of loss of material due to corrosion.
The compressed air monitoring aging management program (AMP) is based on results of the plant owner's response to Nuclear Regulatory Commission (NRC) Generic Letter (GL) 88-14 (as applicable to license renewal) and reported in previous NRC Information Notices (IN) 81-38; IN 87-28; IN 87-28, Supplement 1; and by the Institute of Nuclear Power Operations Significant Operating Experience Report (lNPO SOER) 88-01. NRC GL 88-14, issued after several years of study of problems and failures of instrument air systems, recommends that each holder of an operating license perform an extensive design and operations review and verification of its instrument air system. NRC GL 88-14 also recommends that the licensees describe their program for maintaining proper instrument air quality. This AMP does not include all aspects of NRC GL 88-14 because many of the issues in the GL are not relevant to license renewal.
This AMP does not change the applicant's docketed response to NRC GL 88-14 for the rest of its operations. The program utilizes the aging management aspects of the applicant's response to NRC GL 88-14 for license renewal with regard to preventative measures, inspections of components, and testing to ensure that the compressed air system will be able to perform its intended function for the period of extended operation. The AMP also incorporates the air quality provisions provided in the guidance of the Electric Power Research Institute (EPRI) NP-7079. EPRI NP-7079 was issued in 1990 to assist utilities in identifying and correcting system problems in the instrument air system and to enable them to maintain required industry safety standards. The American Society of Mechanical Engineers (ASM E) operations and maintenance standards and guides (ASME OM-S/G-1998, Part 17) provides additional guidance for maintenance of the instrument air system by offering recommended test methods, test intervals, parameters to be measured and evaluated, acceptance criteria, corrective actions, and records requirements.
Evaluation and Technical Basis
- 1. Scope of Program: The program manages the aging effects of loss of material due to corrosion in compressed air systems.
- 2. Preventive Actions: For the purposes of aging management, moisture and other corrosive contaminants in the system's air are maintained below specified limits to ensure that the system and components maintain their intended functions. These limits are prepared from consideration of manufacturer's recommendations for individual components and guidelines based on ASME OM-S/G-1998, Part 17; American National Standards Institute (ANSI)/ISA-S7.0.01-1996; EPRI NP-7079; and EPRI TR-108147.
- 3. Parameters Monitored/Inspected: Maintaining moisture and other corrosive contaminants below acceptable limits mitigates loss of material due to corrosion. Periodic air samples are taken and analyzed for moisture and other corrosives. Periodic and opportunistic December 201 0 XI M24-1 NUREG-1801, Rev. 2 OAG10001390_00628
inspections of accessible internal surfaces are performed for signs of corrosion and abnormal corrosion products that might indicate a loss of material within the system.
- 4. Detection of Aging Effects: Moisture and other corrosives increase the potential for loss of material due to corrosion. The program periodically samples and tests the air quality in the compressed system for moisture in accordance with industry standards, such as ANSI/ISA-S7.0.01-1996. Typically, compressed systems have in-line dew point instrumentation that either checks continuously using an automatic alarm system or is checked at least daily to ensure that moisture content is within specifications. Additionally, periodic visual inspections of critical component internal surfaces (compressors, dryers, after-coolers, and filters) are performed for signs of loss of material due to corrosion. ASME O/M-S/G-1998, Part 17 provides guidance for inspection frequency and inspection methods of these components.
- 5. Monitoring and Trending: Daily readings of system dew point are recorded and trended.
Air quality analysis results are reviewed to determine if alert levels or limits have been reached or exceeded. This review also checks for unusual trends. ASME O/M-S/G-1998, Part 17, provides guidance for monitoring and trending data. Visual inspection results are compared to previous results to ascertain if adverse long-term trends exist. The effects of corrosion are monitored by visual inspection. Test data are analyzed and compared to data from previous tests to provide for the timely detection of aging effects on passive components.
- 6. Acceptance Criteria: Acceptance criteria for air quality moisture limits are established based on accepted industry standards, such as ANSI/ISA-S7.0.01-1996. Internal surfaces should not show signs of corrosion (general, pitting, and crevice) that could indicate the potential loss of function of the component. Manufacturers' certifications can be used to demonstrate that the bottled air meets acceptable quality standards.
- 7. Corrective Actions: Corrective actions are taken if any parameters are out of acceptable ranges, such as moisture content in the system air. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions.
- 8. Confirmation Process: The site corrective actions program, quality assurance (QA) procedures, site review and approval process, and administrative controls are implemented in accordance with the requirements of 10 CFR Part 50, Appendix B. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the confirmation process and administrative controls.
- 9. Administrative Controls: Site QA procedures, review and approval processes, and administrative controls are implemented in accordance with the requirements of 10 CFR Part 50, Appendix B. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address administrative controls.
- 10. Operating Experience: Potentially significant safety-related problems pertaining to air systems have been documented in NRC IN 81-38; IN 87-28; IN 87-28, Supplement 1; and License Event Report 50-237/94-005-3. Some of the systems that have been significantly degraded or that have failed due to the problems in the air system include the decay heat removal, auxiliary feedwater, main steam isolation, containment isolation, and fuel pool seal systems. In 2008, one plant incurred an unplanned reactor trip from a failure of a mechanical joint in the instrument air system (NRC IN 2008-06). Nevertheless, as a result of NUREG-1801, Rev. 2 XI M24-2 December 201 0 OAG10001390_00629
NRC GL 88-14 and in consideration of INPO SOER 88-01, EPRI NP-7079, and EPRI TR-108147, performance of air systems has improved significantly.
References 10 CFR Part 50, Appendix 8, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
ANSI/ISA-S7.0.01-1996, Quality Standard for Instrument Air, American National Standards Institute (ANSI), 1996.
ASME OM-S/G-1998, Part 17, Performance Testing of Instrument Air Systems Information Notice Light-Water Reactor Power Plants, 1ISA-S7.0.1-1996, "Quality Standard for Instrument Air," American Society of Mechanical Engineers, New York, NY, 1998.
EPRI NP-7079, Instrument Air System: A Guide for Power Plant Maintenance Personnel, Electric Power Research Institute, Palo Alto, CA, December 1990.
EPRI/NMAC TR-108147, Compressor and Instrument Air System Maintenance Guide: Revision to NP-7079, Electric Power Research Institute, Nuclear Maintenance Application Center, Palo Alto, CA, March 1998.
INPO Significant Operating Experience Report 88-01, Instrument Air System Failures, Institute of Nuclear Power Operations, May 18, 1988.
NRC Generic Letter 88-14, Instrument Air Supply Problems Affecting Safety-Related Components, U.S. Nuclear Regulatory Commission, August 8, 1988.
NRC Information Notice 81-38, Potentially Significant Components Failures Resulting from Contamination of Air-Operated Systems, U.S. Nuclear Regulatory Commission, December 17, 1981.
NRC Information Notice 87-28, Air Systems Problems at U.S. Light Water Reactors, U.S. Nuclear Regulatory Commission, June 22, 1987.
NRC Information Notice 87-28, Supplement 1, Air Systems Problems at U.S. Light Water Reactors, U.S. Nuclear Regulatory Commission, December 28, 1987.
NRC Information Notice 2008-06, Instrument Air System Failure Resulting In Manual Reactor Trip, U.S. Nuclear Regulatory Commission, April 10, 2008.
NRC Licensee Event Report 50-237/94-005-3, Manual Reactor Scram due to Loss of Instrument Air Resulting from Air Receiver Pipe Failure Caused by Improper Installation of Threaded Pipe during Initial Construction, U.S. Nuclear Regulatory Commission, April 23, 1997.
December 201 0 XI M24-3 NUREG-1801, Rev. 2 OAG10001390_00630
XI.M25 BWR REACTOR WATER CLEANUP SYSTEM Program Description This program provides inspection to manage the aging effects of cracking due to stress corrosion cracking (SCC) or intergranular stress corrosion cracking (lGSCC) on the intended function of austenitic stainless steel (SS) piping outboard of the second primary containment isolation valves in the reactor water cleanup (RWCU) system. Based on the Nuclear Regulatory Commission (NRC) criteria related to inspection guidelines for RWCU piping welds outboard of the second isolation valve, the program includes the measures delineated in NUREG-0313, Rev. 2, and in NRC Generic Letter (GL) 88-01 and its Supplement 1. The aging management review (AMR) Item in the GALL Report that credits this program also credits AMP XI.M2, "Water Chemistry," to provide mitigation of the aging effects. Reactor coolant water chemistry is monitored and maintained in accordance with the Water Chemistry program.
NRC GL 88-01 applies to all boiling water reactor (BWR) piping made of austenitic SS that is 4 inches or larger in nominal diameter and contains reactor coolant at a temperature above 93.3° C (200° F) during power operation regardless of code classification. NRC GL 88-01 requests, in part, that affected licensees implement an lSI program conforming to staff positions for austenitic SS piping covered under the scope of the letter. In response to NRC GL 88-01, affected licensees undertook lSI in accordance with the scope and schedules described in the letter and included affected portions of RWCU piping outboard of the second isolation valves in their lSI programs.
The NRC issued GL 88-01, Supplement 1, to provide acceptable alternatives to staff positions delineated in NRC GL 88-01. In NRC GL 88-01, Supplement 1, the staff noted, in part, that the position stated in NRC GL 88-01 on inspection sample size of RWCU system welds outboard of the second isolation valves had created an unnecessary hardship for affected licensees because of the very high radiation levels associated with this portion of RWCU piping. The staff also noted that affected licensees had requested that they be exempted from NRC GL 88-01 with regard to inspection of this piping of the RWCU system. Although NRC GL 88-01, Supplement 1, does not provide explicit generic guidance with regard to staff criteria for reduction or elimination of RWCU weld inspections, it does suggest that the staff would be receptive to modifications to a licensee's original docketed NRC GL 88-01 response for RWCU weld inspections, provided all issues of reactor safety were adequately addressed. The staff has subsequently allowed individual licensees to modify their docketed responses to GL-88-01 to reduce or eliminate their lSI of RWCU welds in the piping outboard of the second isolation valves. This AMP is based on the staff-approved screening criteria for the inspection.
Evaluation and Technical Basis
- 1. Scope of Program: This program provides lSI to manage the aging effects of cracking due to SCC or IGSCC in austenitic SS piping outboard of the second containment isolation valves in the RWCU system.
The components included in this program are the welds in piping that have a nominal diameter of 4 inches or larger and that contain reactor coolant at a temperature above 93°C (200°F) during power operation, regardless of code classification.
- 2. Preventive Actions: The comprehensive program outlined in NUREG-0313 and NRC GL 88-01 addresses improvements in all three elements that, in combination, cause December 201 0 XI M2S-1 NUREG-1801, Rev. 2 OAG10001390_00631
SCC or IGSCC. These elements are a susceptible (sensitized) material, a significant tensile stress, and an aggressive environment. The program delineated in NUREG-0313 and NRC GL 88-01 includes recommendations regarding selection of materials that are resistant to sensitization, use of special processes that reduce residual tensile stresses, and monitoring and maintenance of coolant chemistry. The resistant materials are used for new and replacement components and include low-carbon grades of austenitic SS and weld metal, with a maximum carbon of 0.035 wt.% and a minimum ferrite of 7.5% in weld metal and cast austenitic stainless steel (CASS). Special processes are used for existing as well as new and replacement components. These processes include solution heat treatment, heat sink welding, induction heating, and mechanical stress improvement.
- 3. Parameters Monitored/Inspected: The aging management program (AMP) monitors SCC or IGSCC of austenitic SS piping by detecting and sizing cracks in accordance with the requirements of American Society of Mechanical Engineers (ASME) Code,Section XI; the guidelines of NUREG-0313, NRC GL 88-01, and NRC GL 88-01, Supplement 1; and the NRC screening criteria as described in Element 4 for the RWCU piping outboard of the second isolation valves.
- 4. Detection of Aging Effects: The extent, method, and schedule of the inspection and test techniques delineated in the NRC inspection criteria for RWCU piping and NRC GL 88-01 are designed to maintain structural integrity and to detect aging effects before the loss of intended function of austenitic SS piping and fittings. Guidelines for the inspection schedule, methods, personnel, sample expansion, and leak detection guidelines are based on the guidelines of NRC GL 88-01 and GL 88-01, Supplement 1, and subsequent licensing correspondence. Consistent with the NRC guidelines and with licensees' completion of all actions requested in NRC GL 89-10, no inspection of the outboard piping is required for (a) piping systems that are made of IGSCC-resistant piping materials or (b) piping with no IGSCC detected inboard of the second isolation valves (ongoing GL 88-01 inspection) and outboard of the second isolation valves (after inspecting a minimum of 10% of susceptible piping welds). For piping that includes a non-resistant base or weld material in the scope of the program or piping that has experienced IGSCC, either inboard or outboard of the second isolation valves, an inspection of at least 2% of the welds or two welds, whichever is greater, is performed on the portions of the RWCU system outboard of the second isolation valves every refueling outage.
- 5. Monitoring and Trending: The extent and schedule for inspection in accordance with the recommendations of NRC GL 88-01 provide timely detection of cracks and leakage of coolant. Based on inspection results, NRC GL 88-01 provides guidelines for additional samples of welds to be inspected when one or more cracked welds are found in a weld category.
- 6. Acceptance Criteria: NRC GL 88-01 recommends that any indication detected be evaluated in accordance with the requirements of ASME Code,Section XI, Subsection IWB-3640. 15
- 7. Corrective Actions: The guidance for weld overlay repair, stress improvement, or replacement is provided in NRC GL 88-01. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions.
15 Refer to the GALL Report, Chapter I, for applicability of other editions of the ASME Code,Section XI.
NUREG-1801, Rev. 2 XI M2S-2 December 201 0 OAG10001390_00632
- 8. Confirmation Process: Site quality assurance (QA) procedures, review and approval processes, and administrative controls are implemented in accordance with requirements of 10 CFR Part 50, Appendix B. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the confirmation process and administrative controls.
- 9. Administrative Controls: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the administrative controls.
- 10. Operating Experience: The IGSCC has occurred in small- and large-diameter boiling water reactor (BWR) piping made of austenitic stainless steels. The comprehensive program outlined in NRC GL 88-01 and NUREG-0313 addresses improvements in all elements that cause SCC or IGSCC (e.g., susceptible material, significant tensile stress, and an aggressive environment) and is effective in managing IGSCC in austenitic SS piping in the RWCU system.
References 10 CFR Part 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
ASME Section XI, Rules for In service Inspection of Nuclear Power Plant Components, The ASME Boiler and Pressure Vessel Code, 2004 edition as approved in 10 CFR 50.55a The American Society of Mechanical Engineers, New York, NY.
Letter from Joseph W. Shea, U.S. Nuclear Regulatory Commission, to George A. Hunger, Jr.,
PECO Energy Company, Reactor Water Cleanup (RWCU) System Weld Inspections at Peach Bottom Atomic Power Station, Units 2 and 3 (TAC Nos. M92442 and M92443),
September 15, 1995. (ADAMS Accession Number ML090930466)
Letter from Robert M. Pulsifer, U.S. Nuclear Regulatory Commission, to Michael A Balduzzi, Vermont Yankee Nuclear Power Corporation, Review of Request to Discontinue Intergranular Stress Corrosion Cracking Inspection of RWCU Piping Welds Outboard of the Second Containment Isolation Valves (TAC No. MB0468), March 27, 2001. (ADAMS Accession Number ML010780094)
NRC Generic Letter 88-01, NRC Position on IGSCC in BWR Austenitic Stainless Steel Piping, U.S. Nuclear Regulatory Commission, January 25, 1988.
NRC Generic Letter 88-01, Supplement 1, NRC Position on IGSCC in BWR Austenitic Stainless Steel Piping, U.S. Nuclear Regulatory Commission, February 4, 1992.
NRC Generic Letter 89-10, Safety-related Motor Operated Valve Testing and Surveillance, U.S.
Nuclear Regulatory Commission, June 28, 1989; through Supplement 7, January 24, 1996.
NUREG-0313, Rev. 2, Technical Report on Material Selection and Processing Guidelines for BWR Coolant Pressure Boundary Piping, W. S. Hazelton and W. H. Koo, U.S. Nuclear Regulatory Commission, 1988.
December 201 0 XI M2S-3 NUREG-1801, Rev. 2 OAG10001390_00633
XI.M26 FIRE PROTECTION Program Description For operating plants, the Fire Protection aging management program (AMP) includes a fire barrier inspection program. The fire barrier inspection program requires periodic visual inspection of fire barrier penetration seals; fire barrier walls, ceilings, and floors; and periodic visual inspection and functional tests of fire-rated doors to ensure that their operability is maintained. The AMP also includes periodic inspection and testing of the halon/carbon dioxide (C0 2) fire suppression system.
Evaluation and Technical Basis
- 1. Scope of Program: This program manages the effects of loss of material and cracking, increased hardness, shrinkage and loss of strength on the intended function of the penetration seals; fire barrier walls, ceilings, and floors; other fire resistance materials (e.g.,
flamastic, 3M fire wrapping, spray-on fire proofing material, intumescent coating, etc.) that serve a fire barrier function; and all fire-rated doors (automatic or manual) that perform a fire barrier function. It also manages the aging effects on the intended function of the halon/C0 2 fire suppression system.
- 2. Preventive Actions: This is a condition monitoring program. However, the fire hazard analysis assesses the fire potential and fire hazard in all plant areas. It also specifies measures for fire prevention, fire detection, fire suppression, and fire containment and alternative shutdown capability for each fire area containing structures, systems, and components important to safety.
- 3. Parameters Monitored/Inspected: Visual inspection of not less than 10% of each type of penetration seal is performed during walkdowns. These inspections examine any sign of degradation, such as cracking, seal separation from walls and components, separation of layers of material, rupture and puncture of seals that are directly caused by increased hardness, and shrinkage of seal material due to loss of material. Visual inspection of the fire barrier walls, ceilings, and floors and other fire barrier materials detects any sign of degradation, such as cracking, spalling, and loss of material caused by freeze-thaw, chemical attack, and reaction with aggregates that could affect their intended fire protection function. Fire-rated doors are visually inspected to detect any degradation of door surfaces.
The periodic visual inspection and function test are performed to examine for signs of corrosion that may lead to the loss of material of the halon/C0 2 fire suppression system.
- 4. Detection of Aging Effects: Visual inspection of penetration seals detects cracking, seal separation from walls and components, and rupture and puncture of seals. Visual inspection by fire protection qualified personnel of not less than 10% of each type of seal in walkdowns is performed at a frequency in accordance with an NRC-approved fire protection program (e.g., Technical Requirements Manual, Appendix R program, etc.) or at least once every refueling outage. If any sign of degradation is detected within that sample, the scope of the inspection is expanded to include additional seals. Visual inspection by fire protection qualified personnel of the fire barrier walls, ceilings, floors, doors, and other fire barrier materials performed in walkdowns at a frequency in accordance with an NRC-approved fire protection program ensure timely detection of concrete cracking, spalling, and loss of material. Visual inspection by fire protection qualified personnel detects any sign of December 201 0 XI M26-1 NUREG-1801, Rev. 2 OAG10001390_00634
degradation of the fire doors, such as wear and missing parts. Periodic visual inspection and function tests detect degradation of the fire doors before there is a loss of intended function.
Visual inspections of the halon/C0 2 fire suppression system are performed to detect any sign of corrosion. The periodic functional test is performed at least once every 6 months or on a schedule in accordance with an NRC-approved fire protection program. Inspections are performed to detect degradation of the halon/C0 2 fire suppression system before the loss of the component intended function.
- 5. Monitoring and Trending: The results of inspections of the aging effects of cracking, spalling, and loss of material on fire barrier penetration seals, fire barriers, and fire doors are used to trend future actions.
The performance of the halon/C0 2 fire suppression system is monitored during the periodic test to detect any degradation in the system. These periodic tests provide data necessary for trending.
- 6. Acceptance Criteria: Inspection results are acceptable if there are no signs of degradation that could result in the loss of the fire protection capability due to loss of material. The acceptance criteria include (a) no visual indications (outside those allowed by approved penetration seal configurations) of cracking, separation of seals from walls and components, separation of layers of material, or ruptures or punctures of seals; (b) no significant indications of concrete cracking, spalling, and loss of material of fire barrier walls, ceilings, and floors and in other fire barrier materials; (c) no visual indications of missing parts, holes, and wear; and (d) no deficiencies in the functional tests of fire doors. Also, no indications of excessive loss of material due to corrosion in the halon/C0 2 fire suppression system is acceptable.
- 7. Corrective Actions: For fire protection structures and components identified that are subject to an AMR for license renewal, the applicant's 10 CFR Part 50, Appendix 8, program is used for corrective actions, confirmation process, and administrative controls for aging management during the period of extended operation. This corrective action program is documented in the final safety analysis report supplement in accordance with 10 CFR 54.21 (d). As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the corrective actions, confirmation process, and administrative controls.
- 8. Confirmation Process: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the confirmation process.
- 9. Administrative Controls: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the administrative controls.
- 10. Operating Experience: Silicone foam fire barrier penetration seals have experienced splits, shrinkage, voids, lack of fill, and other failure modes (U.S. Nuclear Regulatory Commission
[NRC] Information Notice [IN] 88-56, IN 94-28, and IN 97-70). Degradation of electrical raceway fire barrier such as small holes, cracking, and unfilled seals are found on routine walkdown (NRC IN 91-47 and NRC Generic Letter 92-08). Fire doors have experienced wear of the hinges and handles.
NUREG-1801, Rev. 2 XI M26-2 December 201 0 OAG10001390_00635
References 10 CFR Part 50, Appendix 8, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
NRC Generic Letter 92-08, Thermo-Lag 330-1 Fire Barrier, U.S. Nuclear Regulatory Commission, December 17, 1992.
NRC Information Notice 88-56, Potential Problems with Silicone Foam Fire Barrier Penetration Seals, U.S. Nuclear Regulatory Commission, August 14, 1988.
NRC Information Notice 91-47, Failure of Thermo-Lag Fire Barrier Material to Pass Fire Endurance Test, U.S. Nuclear Regulatory Commission, August 6, 1991.
NRC Information Notice 94-28, Potential Problems with Fire-Barrier Penetration Seals, U.S.
Nuclear Regulatory Commission, AprilS, 1994.
NRC Information Notice 97-70, Potential Problems with Fire Barrier Penetration Seals, U.S.
Nuclear Regulatory Commission, September 19, 1997.
December 201 0 XI M26-3 NUREG-1801, Rev. 2 OAG10001390_00636
XI.M27 FIRE WATER SYSTEM Program Description This aging management program (AMP) applies to water-based fire protection systems that consist of sprinklers, nozzles, fittings, valves, fire pump casings, hydrants, hose stations, standpipes, water storage tanks, and aboveground, buried, and underground piping and components that are tested in accordance with the applicable National Fire Protection Association (NFPA) codes and standards. Such testing assures the minimum functionality of the systems. Also, these systems are normally maintained at required operating pressure and monitored such that loss of system pressure is immediately detected and corrective actions initiated.
A sample of sprinkler heads is tested by using the guidance of NFPA 25, "Inspection, Testing and Maintenance of Water-Based Fire Protection Systems" (1998 Edition), Section 2-3.1.1, or NFPA 25 (2002 Edition), Section 5.3.1.1.1. These NFPA sections state "where sprinklers have been in place for 50 years, they shall be replaced or representative samples from one or more sample areas shall be submitted to a recognized testing laboratory for field service testing." It also contains guidance to perform this sampling every 10 years after the initial field service testing.
The water-based fire protection system piping is subjected to required flow testing in accordance with guidance in NFPA 25 to verify design pressure or evaluated for wall thickness (e.g., non-intrusive volumetric testing or plant maintenance visual inspections) to ensure that aging effects are managed and that wall thickness is within acceptable limits. These inspections are performed before the end of the current operating term and at plant-specific intervals thereafter during the period of extended operation. The plant-specific inspection intervals are determined by engineering evaluation of the fire protection piping to ensure that degradation is detected before the loss of intended function. The purpose of the full flow testing and wall thickness evaluations is to ensure that corrosion, microbiologically influenced corrosion (MIC),
or biofouling is managed such that the system function is maintained.
Chapter XI.M41 describes the aging management program for buried and underground water-based fire protection system piping and tanks.
Evaluation and Technical Basis
- 1. Scope of Program: The AMP focuses on managing loss of material due to corrosion, MIC, or biofouling of steel components in fire protection systems exposed to water. Fire hose stations and standpipes are considered as piping in the AMP. Fire hoses and gaskets can be excluded from the scope of license renewal if the standards that are relied upon to prescribe replacement of the hose and gaskets are identified in the scoping methodology description.
- 2. Preventive Actions: To ensure that no significant corrosion, MIC, or biofouling has occurred in water-based fire protection systems, periodic flushing and system performance testing are conducted in accordance with NFPA 25.
- 3. Parameters Monitored/Inspected: Loss of material due to corrosion and biofouling could reduce wall thickness of the fire protection piping system and result in system failure.
Therefore, the parameters monitored are the system's ability to maintain pressure and December 201 0 XI M27-1 NUREG-1801, Rev. 2 OAG10001390_00637
internal system corrosion conditions. Periodic flow testing of the fire water system is performed using the guidelines of NFPA 25, or wall thickness evaluations may be performed to ensure that the system maintains its intended function. Testing of sprinklers ensures that degradation is detected in timely manner.
- 4. Detection of Aging Effects: The water-based fire protection system testing is performed to ensure that the system functions by maintaining required operating pressures. Wall thickness evaluations of fire protection piping are performed on system components using non-intrusive techniques (e.g., volumetric testing) to identify evidence of loss of material due to corrosion. These inspections are performed before the end of the current operating term and at plant-specific intervals thereafter during the period of extended operation.
As an alternative to non-intrusive testing, the plant maintenance process may include a visual inspection of the internal surface of the fire protection piping upon each entry to the system for routine or corrective maintenance, as long as it can be demonstrated that inspections are performed (based on past maintenance history) on a representative number of locations on a reasonable basis. These inspections are capable of evaluating (a) wall thickness to ensure against catastrophic failure and (b) the inner diameter of the piping as it applies to the design flow of the fire protection system.
If the environmental and material conditions that exist on the interior surface of the below grade fire protection piping are similar to the conditions that exist within the above grade fire protection piping, the results of the inspections of the above grade fire protection piping can be extrapolated to evaluate the condition of below grade fire protection piping. If not, additional inspection activities are needed to ensure that the intended function of below grade fire protection piping is maintained consistent with the current licensing basis for the period of extended operation.
Continuous system pressure monitoring, system flow testing, and wall thickness evaluations of piping are effective means to ensure that corrosion and biofouling are not occurring and that the system's intended function is maintained.
General requirements of existing fire protection programs include testing and maintenance of fire detection and protection systems and surveillance procedures to ensure that fire detectors as well as fire protection systems and components are operable.
Visual inspection of yard fire hydrants, performed annually in accordance with NFPA 25, ensures timely detection of signs of degradation, such as corrosion. Fire hydrant hose hydrostatic tests, gasket inspections, and fire hydrant flow tests, performed annually, ensure that fire hydrants can perform their intended function and provide opportunities to detect degradation before a loss of intended function can occur. Sprinkler heads are tested before the end of the 50-year sprinkler head service life and at 10-year intervals thereafter during the period of extended operation to ensure that signs of degradation, such as corrosion, are detected in a timely manner.
- 5. Monitoring and Trending: System discharge pressure is monitored continuously. Results of system performance testing are monitored and trended as specified by the associated plant commitments pertaining to NFPA codes and standards. Degradation identified by non-intrusive or visual inspection is evaluated.
NUREG-1801, Rev. 2 XI M27-2 December 201 0 OAGI0001390_00638
- 6. Acceptance Criteria: The acceptance criteria are (a) the water-based fire protection system is able to maintain required pressure, (b) no unacceptable signs of degradation are observed during non-intrusive or visual inspection of components, (c) minimum design pipe wall thickness is maintained, and (d) no biofouling exists in the sprinkler systems that could cause corrosion in the sprinklers.
- 7. Corrective Actions: Repair and replacement actions are initiated as necessary. For fire water systems and components identified within scope that are subject to an aging management review (AMR) for license renewal, the applicant's 10 CFR Part 50, Appendix 8, program is used for corrective actions for aging management during the period of extended operation. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the corrective actions.
- 8. Confirmation Process: For fire water systems and components identified within scope that are subject to an AMR for license renewal, the applicant's 10 CFR Part 50, Appendix 8, program is used for confirmation process for aging management during the period of extended operation. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the confirmation process.
- 9. Administrative Controls: For the water-based fire water systems and components identified within scope that are subject to an AMR for license renewal, the applicant's 10 CFR Part 50, Appendix 8, program is used for administrative controls for aging management during the period of extended operation. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the administrative controls.
- 10. Operating Experience: Water-based fire protection systems designed, inspected, tested, and maintained in accordance with the NFPA minimum standards have demonstrated reliable performance.
References 10 CFR Part 50, Appendix 8, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
NFPA 25, Inspection, Testing and Maintenance of Water-Based Fire Protection Systems, 1998 Edition, National Fire Protection Association.
NFPA 25, Inspection, Testing and Maintenance of Water-Based Fire Protection Systems, 2002 Edition, National Fire Protection Association.
December 201 0 XI M27-3 NUREG-1801, Rev. 2 OAG10001390_00639
XI.M29 ABOVEGROUND METALLIC TANKS Program Description The Aboveground Metallic Tanks aging management program (AMP) manages the effects of loss of material on the outer surfaces of above ground tanks constructed on concrete or soil. If the tank exterior is fully visible, the program for inspection of external surfaces may be used instead (XI.M36). This program credits the standard industry practice of coating or painting the external of steel tanks as a preventive measure to mitigate corrosion. The program relies on periodic inspections to monitor degradation of the protective paint or coating. However, for storage tanks supported on earthen or concrete foundations, corrosion may occur at inaccessible locations, such as the tank bottom. Accordingly, verification of the effectiveness of the program is performed to ensure that significant degradation in inaccessible locations is not occurring and that the component intended function is maintained during the period of extended operation. For reasons set forth below, an acceptable verification program consists of thickness measurement of the tank bottom surface.
Evaluation and Technical Basis
- 1. Scope of Program: The program consists of periodic inspections of metallic tanks (with or without coatings) to manage the effects of corrosion on the intended function of these tanks.
Inspections cover the entire outer surface of the tank. Because lower portions of the tank are on concrete or soil, this program includes the bottom of the tank as well. If the tank exterior is fully visible, the program for inspection of external surfaces may be used instead (AMP XI.M36).
- 2. Preventive Actions: In accordance with industry practice, tanks may be coated with protective paint or coating to mitigate corrosion by protecting the external surface of the tank from environmental exposure. Sealant or caulking may be applied at the external interface between the tank and concrete or earthen foundation to mitigate corrosion of the bottom surface of the tank by minimizing the amount of water and moisture penetrating the interface, which would lead to corrosion of the bottom surface.
- 3. Parameters Monitored/Inspected: The AMP utilizes periodic plant inspections to monitor degradation of coatings, sealants, and caulking because it is a condition directly related to the potential loss of materials. Additionally, thickness measurements of the bottoms of the tanks are made periodically for the tanks monitored by this program as an additional measure to ensure that loss of material is not occurring at locations that are inaccessible for inspection.
- 4. Detection of Aging Effects: Degradation of an exterior metallic surface can occur in the presence of moisture; therefore, an inspection of the coating is performed to ensure that the surface is protected from moisture. Conducting periodic visual inspections at each outage to confirm that the paint, coating, sealant, and caulking are intact is an effective method to manage the effects of corrosion on the external surface of the component. Potential corrosion of tank bottoms is determined by taking ultrasonic testing (UT) thickness measurements of the tank bottoms whenever the tank is drained and at least once within 5 years of entering the period of extended operation. Measurements are taken to ensure that significant degradation is not occurring and that the component intended function is maintained during the period of extended operation.
December 201 0 XI M29-1 NUREG-1801, Rev. 2 OAGI0001390_00640
- 5. Monitoring and Trending: The effects of corrosion of the aboveground external surface are detectable by visual techniques. Based on operating experience, plant inspections during each outage provide for timely detection of aging effects. The effects of corrosion of the inaccessible external surface are detectable by UT thickness measurement of the tank bottom and are monitored and trended if significant material loss is detected where multiple measurements are available.
- 6. Acceptance Criteria: Any degradation of paints or coatings (cracking, flaking, or peeling) is reported and requires further evaluation. Drying, cracking, or missing sealant and caulking are unacceptable and need to be evaluated using the corrective action program. The evaluation will determine the need to repair the sealant and caulking. UT thickness measurements of the tank bottom are evaluated against the design thickness and corrosion allowance.
- 7. Corrective Actions: The site corrective actions program, quality assurance procedures, site review and approval process, and administrative controls are implemented in accordance with 10 CFR Part 50, Appendix B. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions, confirmation process, and administrative controls. Flaws in the caulking or sealant are repaired.
- 8. Confirmation Process: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the confirmation process.
- 9. Administrative Controls: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the administrative controls.
- 10. Operating Experience: Coating degradation, such as flaking and peeling, has occurred in safety-related systems and structures (U.S. Nuclear Regulatory Commission [NRC] Generic Letter 98-04). Corrosion damage near the concrete-metal interface and sand-metal interface has been reported in metal containments (NRC Information Notice [IN] 89-79; IN 89-79, Supplement 1; IN 86-99; and IN 86-99, Supplement 1).
References 10 CFR Part 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
NRC Generic Letter 98-04, Potential for Degradation of the Emergency Core Cooling System and the Containment Spray System after a Loss-of-Coo/ant Accident Because of Construction and Protective Coating Deficiencies and Foreign Material in Containment, U.S. Nuclear Regulatory Commission, July 14, 1998.
NRC Information Notice 86-99, Degradation of Steel Containments, U.S. Nuclear Regulatory Commission, December 8, 1986.
NRC Information Notice 86-99, Supplement 1, Degradation of Steel Containments, U.S. Nuclear Regulatory Commission, February 14, 1991.
NUREG-1801, Rev. 2 XI M29-2 December 201 0 OAG10001390_00641
NRC Information Notice 89-79, Oegraded Coatings and Corrosion of Steel Containment Vessel, U.S. Nuclear Regulatory Commission, December 1, 1989.
NRC Information Notice 89-79, Supplement 1, Oegraded Coatings and Corrosion of Steel Containment Vessel, U.S. Nuclear Regulatory Commission, June 29, 1990.
December 201 0 XI M29-3 NUREG-1801, Rev. 2 OAG10001390_00642
XI.M30 FUEL OIL CHEMISTRY Program Description The program includes (a) surveillance and maintenance procedures to mitigate corrosion and (b) measures to verify the effectiveness of the mitigative actions and confirm the insignificance of an aging effect. Fuel oil quality is maintained by monitoring and controlling fuel oil contamination in accordance with the plant's technical specifications. Guidelines of the American Society for Testing Materials (ASTM) Standards, such as ASTM 00975-04, 0 1796-97, 02276-00, 02709-96, 06217-98, and 04057-95, also may be used. Exposure to fuel oil contaminants, such as water and microbiological organisms, is minimized by periodic draining or cleaning of tanks and by verifying the quality of new oil before its introduction into the storage tanks. However, corrosion may occur at locations in which contaminants may accumulate, such as tank bottoms. Accordingly, the effectiveness of the program is verified to ensure that significant degradation is not occurring and that the component's intended function is maintained during the period of extended operation. Thickness measurement of tank bottom surfaces is an acceptable verification program.
The fuel oil chemistry program is generally effective in removing impurities from intermediate and high flow areas. This report identifies those circumstances in which the fuel oil chemistry program is to be augmented to manage the effects of aging for license renewal. For example, the fuel oil chemistry program may not be effective in low flow or stagnant flow areas.
Accordingly, in certain cases as identified in this report, verification of the effectiveness of the chemistry program is undertaken to ensure that significant degradation is not occurring and that the component's intended function is maintained during the period of extended operation. As discussed in this report for these specific cases, an acceptable verification program is a one-time inspection of selected components at susceptible locations in the system.
Evaluation and Technical Basis
- 1. Scope of Program: Components within the scope of the program are the diesel fuel oil storage tanks, piping, and other metal components subject to aging management review that are exposed to an environment of diesel fuel oil. The program is focused on managing loss of material due to general, pitting, crevice, and microbiologically-influenced corrosion (MIC) and fouling that leads to corrosion of the diesel fuel tank internal surfaces.
- 2. Preventive Actions: The program reduces the potential for (a) exposure of the storage tanks' internal surface to fuel oil contaminated with water and microbiological organisms, reducing the potential for age-related degradation in other components exposed to diesel fuel oil; and (b) transport of corrosion products, sludge, or particulates to components serviced by the fuel oil storage tanks. Biocides or corrosion inhibitors may be added as a preventive measure or are added if periodic testing indicates biological activity or evidence of corrosion. Periodic cleaning of a tank allows removal of sediments, and periodic draining of water collected at the bottom of a tank minimizes the amount of water and the length of contact time. Accordingly, these measures are effective in mitigating corrosion inside diesel fuel oil tanks. Coatings, if used, prevent or mitigate corrosion by protecting the internal surfaces of the tank from contact with water and microbiological organisms.
- 3. Parameters Monitored/Inspected: The program is focused on managing loss of material due to general, pitting, crevice, and MIC, and fouling that leads to corrosion of the diesel fuel tank internal surfaces. The aging management program monitors fuel oil quality through December 201 0 XI M30-1 NUREG-1801, Rev. 2 OAG10001390_00643
receipt testing and periodic sampling of stored fuel oil. Parameters monitored include water and sediment content, total particulate concentration, and the levels of microbiological organisms in the fuel oil. Water and microbiological organisms in the fuel oil storage tank increase the potential for corrosion. Sediment and total particulate content may be indicative of water intrusion or corrosion.
- 4. Detection of Aging Effects: Loss of material due to corrosion of the diesel fuel oil tank or other components exposed to diesel fuel oil cannot occur without exposure of the tank's internal surfaces to contaminants in the fuel oil, such as water and microbiological organisms. Periodic multilevel sampling provides assurance that fuel oil contaminants are below unacceptable levels. If tank design features do not allow for multilevel sampling, a sampling methodology that includes a representative sample from the lowest point in the tank may be used.
At least once during the 1O-year period prior to the period of extended operation, each diesel fuel tank is drained and cleaned, the internal surfaces are visually inspected (if physically possible) and volumetrically-inspected if evidence of degradation is observed during visual inspection, or if visual inspection is not possible. During the period of extended operation, at least once every 10 years, each diesel fuel tank is drained and cleaned, the internal surfaces are visually inspected (if physically possible), and, if evidence of degradation is observed during inspections, or if visual inspection is not possible, these diesel fuel tanks are volumetrically inspected.
Prior to the period of extended operation, a one-time inspection (i.e., AMP XI.M32) of selected components exposed to diesel fuel oil is performed to verify the effectiveness of the Fuel Oil Chemistry program.
- 5. Monitoring and Trending: Water, biological activity, and particulate contamination concentrations are monitored and trended in accordance with the plant's technical specifications or at least quarterly.
- 6. Acceptance Criteria: Acceptance criteria for fuel oil quality parameters are as invoked or referenced in a plant's technical specifications. Additional acceptance criteria may be implemented using guidance from industry standards and equipment manufacturer or fuel oil supplier recommendations. ASTM D 0975-04 or other appropriate standards may be used to develop fuel oil quality acceptance criteria. Suspended water concentrations are in accordance with the applicable fuel oil quality specifications. Corrective actions are taken if microbiological activity is detected.
- 7. Corrective Actions: Specific corrective actions are implemented in accordance with the plant quality assurance (QA) program. For example, corrective actions are taken to prevent recurrence when the specified limits for fuel oil standards are exceeded or when water is drained during periodic surveillance. If accumulated water is found in a fuel oil storage tank, it is immediately removed. In addition, when the presence of biological activity is confirmed, a biocide is added to fuel oil. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions.
- 8. Confirmation Process: Site QA procedures, review and approval processes, and administrative controls are implemented in accordance with the requirements of 10 CFR Part 50, Appendix B. As discussed in the Appendix for GALL, the staff finds the NUREG-1801, Rev. 2 XI M30-2 December 201 0 OAG10001390_00644
requirements of 10 CFR Part 50, Appendix B, acceptable to address the confirmation process and administrative controls.
- 9. Administrative Controls: The administrative controls for this program provide for a formal review and approval of corrective actions. The administrative controls for this program are implemented through the site's QA program in accordance with the requirements of 10 CFR Part 50, Appendix B.
- 10. Operating Experience: The operating experience at some plants has included identification of water in the fuel, particulate contamination, and biological fouling. In addition, when a diesel fuel oil storage tank at one plant was cleaned and visually inspected, the inside of the tank was found to have unacceptable pitting corrosion (>50% of the wall thickness), which was repaired in accordance with American Petroleum Institute (API) 653 standard by welding patch plates over the affected area.
References 10 CFR Part 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
API 653, Tank Inspection, Repair, Alteration, and Reconstruction, American Petroleum Institute, April 23, 2009.
ASTM 00975-04, Standard Specification for Diesel Fuel Oils, American Society for Testing Materials, West Conshohocken, PA, 2004.
ASTM 0 1796-97, Standard Test Method for Water and Sediment in Fuel Oils by the Centrifuge Method, American Society for Testing Materials, West Conshohocken, PA, 1997.
ASTM 0 2276-00, Standard Test Method for Particulate Contaminant in Aviation Fuel by Line Sampling, American Society for Testing Materials, West Conshohocken, PA, 2000.
ASTM 0 2709-96, Standard Test Method for Water and Sediment in Middle Distillate Fuels by Centrifuge, American Society for Testing Materials, West Conshohocken, PA, 1996.
ASTM 0 4057-95, Standard Practice for Manual Sampling of Petroleum and Petroleum Products, American Society for Testing Materials, West Conshohocken, PA, 2000.
ASTM 06217-98, Standard Test Method for Particulate Contamination in Middle Distillate Fuels by Laboratory Filtration, American Society for Testing Materials, West Conshohocken, PA, 1998.
NRC Regulatory Guide 1.137, Rev. 1, Fuel-Oil Systems for Standby Diesel Generators, U.S.
Nuclear Regulatory Commission, October 1979.Safety Evaluation Report Related to the License Renewal of Three Mile Island Nuclear Unit 1, Section 3.0.3.2.12, Fuel Oil Chemistry
- Operating Experience, June 2009.
December 201 0 XI M30-3 NUREG-1801, Rev. 2 OAG10001390_00645
XI.M31 REACTOR VESSEL SURVEILLANCE Program Description The Code of Federal Regulations, 10 CFR Part 50, Appendix H, requires that peak neutron fluence at the end of the design life of the vessel will not exceed 10 17 n/cm 2 (E >1 MeV), or that reactor vessel beltline materials be monitored by a surveillance program to meet the American Society for Testing and Materials (ASTM) E 185 Standard. However, the surveillance program in ASTM International Standard Practice E 185-82 is based on plant operation during the current license term, and additional surveillance capsules may be needed for the period of extended operation. Alternatively, an integrated surveillance program for the period of extended operation may be considered for a set of reactors that have similar design and operating features in accordance with 10 CFR Part 50, Appendix H (2009), Paragraph III.C. Additional surveillance capsules may also be needed for the period of extended operation for this alternative.
The objective of the reactor vessel material surveillance program is to provide sufficient material data and dosimetry to (a) monitor irradiation embrittlement at the end of the period of extended operation and (b) determine the need for operating restrictions on the inlet temperature, neutron spectrum, and neutron flux. If surveillance capsules are not withdrawn during the period of extended operation, operating restrictions are to be established to ensure that the plant is operated under the conditions to which the surveillance capsules were exposed.
The program is a condition monitoring program that measures the increase in Charpy V-notch 30 foot-pound (ft-Ib) transition temperature and the drop in the upper shelf energy as a function of neutron fluence and irradiation temperature. The data from this surveillance program are used to monitor neutron irradiation embrittlement and are used in the time-limited aging analyses that are described in Section 4.2 of the Standard Review Plan for License Renewal. All capsules in the reactor vessel that are removed and tested must meet the test procedures and reporting requirements of the 1982 edition of ASTM E 185 (ASTM E 185-82), to the extent practicable, for the configuration of the specimens in the capsule. Any changes to the capsule withdrawal schedule, including spare capsules, must be approved by the Nuclear Regulatory Commission (NRC) prior to implementation. Untested capsules placed in storage must be maintained for possible future insertion.
Evaluation and Technical Basis The Reactor Vessel Surveillance program is plant-specific, depending on matters such as the composition of limiting materials, availability of surveillance capsules, and projected fluence levels. In accordance with 10 CFR Part 50, Appendix H, an applicant submits its proposed withdrawal schedule for approval prior to implementation. Thus, further staff evaluation is required for license renewal.
- 1. Scope of Program: The program includes all reactor vessel beltline materials as defined by 10 CFR 50, Appendix G, Section II.F. Materials originally monitored within the scope of the licensee's existing 10 CFR Part 50, Appendix H, materials surveillance program will continue to serve as the basis for the reactor vessel surveillance aging management program unless safety considerations for the term of the renewed license would require the monitoring of additional or alternative materials.
December 201 0 XI M31-1 NUREG-1801, Rev. 2 OAG10001390_00646
- 2. Preventive Actions: The program is a surveillance program; no preventive actions are identified.
- 3. Parameters Monitored/Inspected: The program monitors reduction of fracture toughness of reactor vessel beltline materials due to neutron irradiation embrittlement and monitors reactor vessel long term operating conditions (cold leg operating temperature and neutron fluence) that could affect neutron irradiation embrittlement of the reactor vessel. The program uses two parameters to monitor the effects of neutron irradiation: (a) the increase in the Charpy V-notch 30 ft-Ib transition temperature and (b) the drop in the Charpy V-notch upper shelf energy. The program uses neutron dosimeters to benchmark neutron fluence calculations. Low melting point elements or eutectic alloys may be used as a check on peak specimen irradiation temperature. Preferably, irradiation temperature will be monitored from cold leg operating temperatures. The Charpy V-notch specimens, neutron dosimeters, and temperature monitors are placed in capsules that are located within the reactor vessel; the capsules are withdrawn periodically to monitor the reduction in fracture toughness due to neutron irradiation.
- 4. Detection of Aging Effects: Reactor vessel beltline materials will be monitored by a surveillance program in which surveillance capsules are withdrawn from the reactor vessel and tested in accordance with ASTM E 185-82. This ASTM standard describes the methods used to monitor irradiation embrittlement (described in Element 3, above), selection of materials, and the withdrawal schedule for capsules. However, the surveillance program in ASTM E 185 is based on plant operation during the current license term, and additional surveillance capsules may be needed for the period of extended operation. Alternatively, an integrated surveillance program for the period of extended operation may be considered for a set of reactors that have similar design and operating features in accordance with 10 CFR Part 50, Appendix H, Paragraph III.C. Additional surveillance capsules may also be needed for the period of extended operation for this alternative.
The plant-specific or integrated surveillance program shall have at least one capsule with a projected neutron fluence equal to or exceeding the 60-year peak reactor vessel wall neutron fluence prior to the end of the period of extended operation. The program withdraws one capsule at an outage in which the capsule receives a neutron fluence of between one and two times the peak reactor vessel wall neutron fluence at the end of the period of extended operation and tests the capsule in accordance with the requirements of ASTM E 185-82.
It is recommended that the program retain additional capsules within the reactor vessel to support additional testing if, for example, the data from the required surveillance capsule turn out to be invalid or in preparation for operation beyond 60 years. If the projected neutron fluence for these additional capsules is expected to be excessive if left in the reactor vessel, the program may propose to withdraw and place one or more untested capsules in storage for future reinsertion and/or testing.
If a plant has ample capsules remaining for future use, all pulled and tested samples or capsules placed in storage with reactor vessel neutron fluence less than 50% of the projected neutron fluence at the end of the period of extended operation may be discarded.
Pulled and tested samples, unless discarded before August 31, 2000, and capsules with a neutron fluence greater than 50% of the projected reactor vessel neutron fluence at the end of the period of extended operation are placed in storage (these specimens and capsules NUREG-1801, Rev. 2 XI M31-2 December 201 0 OAG10001390_00647
are saved for future reconstitution and reinsertion use) unless the applicant has gained NRC approval to discard the pulled and tested samples or capsules.
If an applicant does not have ample capsules remaining for future use, all pulled and tested capsules, unless discarded before August 31, 2000, are placed in storage. (These specimens are saved for future reconstitution use, in case the surveillance program is reestablished.)
Plant-specific and fleet operating experience should be considered in determining the withdrawal schedule for all capsules; the withdrawal schedule shall be submitted as part of a license renewal application for NRC review and approval in accordance with 10 CFR Part 50, Appendix H.
If all surveillance capsules have been removed, a licensee may seek membership in an integrated surveillance program unless the integrated surveillance program does not have surveillance material representative of its limiting beltline materials or the program can propose one of the following:
(a) An Active Surveillance Program with Reinstituted Specimens This program consists of (1) capsules from a surveillance program described above, (2) reconstitution of specimen from tested capsules, (3) capsules made from any available archival materials, or (4) some combination of the three previous options. This program could be a plant-specific program or an integrated surveillance program.
(b) An Alternative Neutron Monitoring Program Programs without in-vessel capsules use alternative dosimetry to monitor neutron fluence during the period of extended operation.
If all surveillance capsules have been removed, operating restrictions are established to ensure that the plant is operated under conditions to which the surveillance capsules were exposed. The exposure conditions of the reactor vessel are monitored to ensure that they continue to be consistent with those used to project the effects of embrittlement to the end of license. If the reactor vessel exposure conditions (neutron flux, spectrum, irradiation temperature, etc.) are altered, then the basis for the projection to 60 or more years is reviewed and, if deemed appropriate, modifications are made to the Reactor Vessel Surveillance program. Any changes to the Reactor Vessel Surveillance program must be submitted for NRC review and approval in accordance with 10 CFR Part 50, Appendix H.
- 5. Monitoring and Trending: The program provides reactor vessel material fracture toughness data for the time limited aging analyses (TLAAs) on neutron irradiation embrittlement (e.g., upper-shelf energy, pressurized thermal shock and pressure-temperature limits evaluations, etc.) for 60 years. The program is designed to periodically remove and test capsules for monitoring and trending purposes. Refer to the Standard Review Plan for License Renewal, Section 4.2, for the NRC acceptance criteria and review procedures for reviewing TLAAs for neutron irradiation embrittlement.
The TLAAs are projected in accordance with NRC Regulatory Guide (RG) 1.99, Rev. 2, "Radiation Embrittlement of Reactor Vessel Materials," and the pressurized thermal shock December 201 0 XI M31-3 NUREG-1801, Rev. 2 OAG10001390_00648
rules (10 CFR 50.61 or 10 CFR 50.61a). When using NRC RG 1.99, Rev. 2, or equivalent provisions in 10 CFR 50.61, a licensee has a choice of the following:
(a) Neutron Embrittlement Using Chemistry Tables and Upper Shelf Energy Figures An applicant may use the tables and figures in NRC RG 1.99, Rev. 2, to project the extent of reactor vessel neutron embrittlement for the period of extended operation based on material chemistry and neutron fluence. This is described as Regulatory Position 1 in NRC RG 1.99, Rev. 2.
(b) Neutron Embrittlement Using Surveillance Data When two or more credible surveillance data sets are available, the extent of reactor vessel neutron embrittlement for the period of extended operation may be projected according to Regulatory Position 2 in NRC RG 1.99, Rev. 2, based on best fit of the surveillance data. The credible data could be collected during the current and extended operating term. A plant-specific program or an integrated surveillance program during the period of extended operation provides for the collection of additional data.
A program that determines embrittlement by using NRC RG 1.99, Rev. 2, tables and figures (item [a]) uses the applicable limitations in Regulatory Position 1.3 of NRC RG 1.99, Rev. 2.
The limits are based on material properties, temperature, material chemistry, and neutron fluence.
The program that determines embrittlement by using surveillance data (item [b]) defines the applicable bounds of the data, such as cold leg operating temperature and neutron fluence.
These bounds are specific for the referenced surveillance data. For example, the plant-specific data could be collected within a smaller temperature range than that in NRC RG 1.99, Rev. 2.
The reactor vessel monitoring program provides that if future plant operations exceed these limitations or bounds, such as operating at a lower cold leg temperature or higher fluence, the impact of plant operation changes on the extent of reactor vessel embrittlement is evaluated and the NRC is notified.
- 6. Acceptance Criteria: The data are used for reactor vessel embrittlement projections to comply with 10 CFR Part 50, Appendix G, requirements and 10 CFR 50.61 or 10 CFR 50.61 a limits through the period of extended operation.
- 7. Corrective Actions: There are no acceptance criteria that apply to the surveillance data, but the results of surveillance capsule testing will be incorporated into site operating limitations. The data will be used for reactor vessel embrittlement projections to comply with 10 CFR Part 50, Appendix G, requirements and 10 CFR 50.61 or 10 CFR 50.61a limits through the period of extended operation.
If a capsule is not withdrawn as scheduled, the NRC is notified and a revised withdrawal schedule is submitted to the NRC.
Site quality assurance (QA) procedures, review and approval processes, and administrative controls are implemented in accordance with the requirements of 10 CFR Part 50, Appendix NUREG-1801, Rev. 2 XI M31-4 December 201 0 OAG10001390_00649
B. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions.
- 8. Confirmation Process: Site QA procedures, review and approval processes, and administrative controls are implemented in accordance with the requirements of 10 CFR Part 50, Appendix B. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the confirmation process, and administrative controls.
- 9. Administrative Controls: The administrative controls for this program provide for a formal review and approval of corrective actions. The administrative controls for this program are implemented through the site's QA program in accordance with the requirements of 10 CFR Part 50, Appendix B.
- 10. Operating Experience: The existing reactor vessel material surveillance program provides sufficient material data and dosimetry to (a) monitor irradiation embrittlement at the end of the period of extended operation and (b) determine the need for operating restrictions on the inlet temperature, neutron fluence, and neutron flux.
References 10 CFR Part 50, Appendix G, Fracture Toughness Requirements, Office of the Federal Register, National Archives and Records Administration, 2009.
10 CFR Part 50, Appendix H, Reactor Vessel Material Surveillance Program Requirements, Office of the Federal Register, National Archives and Records Administration, 2009.
10 CFR 50.61, Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock Events, Office of the Federal Register, National Archives and Records Administration, January 4,2010.
10 CFR 50.61a, Alternate Fracture Toughness Requirements for Protection Against Pressurized Thermal Shock Events, Office of the Federal Register, National Archives and Records Administration, January 4,2010.
ASTM E 185-82, Standard Practice for Conducting Surveillance Tests of Light-Water Cooled Nuclear Power Reactor Vessels, American Society for Testing Materials, Philadelphia, PA.
(Versions of ASTM E 185 to be used for the various aspects of the reactor vessel surveillance program are as specified in 10 CFR Part 50, Appendix H.)
NRC Regulatory Guide 1.99, Rev. 2, Radiation Embrittlement of Reactor Vessel Materials, U.S.
Nuclear Regulatory Commission, May 1988.
December 201 0 XI M31-S NUREG-1801, Rev. 2 OAG10001390_00650
XI.M32 ONE-TIME INSPECTION Program Description A one-time inspection of selected components is used to verify the system-wide effectiveness of an aging management program (AMP) that is designed to prevent or minimize aging to the extent that it will not cause the loss of intended function during the period of extended operation.
For example, effective control of water chemistry under the XI.M2, "Water Chemistry," program can prevent some aging effects and minimize others. However, there may be locations that are isolated from the flow stream for extended periods and are susceptible to the gradual accumulation or concentration of agents that promote certain aging effects. This program provides inspections that verify that unacceptable degradation is not occurring. It also may trigger additional actions that ensure the intended functions of affected components are maintained during the period of extended operation.
The program verifies the effectiveness of an AMP and confirms the insignificance of an aging effect. Situations in which additional confirmation is appropriate include (a) an aging effect is not expected to occur, but the data are insufficient to rule it out with reasonable confidence; or (b) an aging effect is expected to progress very slowly in the specified environment, but the local environment may be more adverse than generally expected. For these cases, confirmation demonstrates that either the aging effect is not occurring or that the aging effect is occurring very slowly and does not affect the component's or structure's intended function during the period of extended operation based on prior operating experience data.
This program does not address Class 1 piping less than nominal pipe size (NPS) 4. That piping is addressed in AMP XI.M35, "One Time Inspection of ASME Code Class 1 Small Bore-Piping."
The elements of the program include (a) determination of the sample size of components to be inspected based on an assessment of materials of fabrication, environment, plausible aging effects, and operating experience; (b) identification of the inspection locations in the system or component based on the potential for the aging effect to occur; (c) determination of the examination technique, including acceptance criteria that would be effective in managing the aging effect for which the component is examined; and (d) evaluation of the need for follow-up examinations to monitor the progression of aging if age-related degradation is found that could jeopardize an intended function before the end of the period of extended operation.
An acceptable (one-time inspection) program to verify system-wide effectiveness of an AMP may consist of a one-time inspection of selected components and susceptible locations in the selected system. Verification may include a review of routine maintenance, repair, or inspection records to confirm that selected components have been inspected for aging degradation and that significant aging degradation has not occurred. A one-time inspection program is acceptable to verify the effectiveness of AMP XI.M2, "Water Chemistry"; AMP XI.M30, "Fuel Oil Chemistry"; and AMP XI.M39, "Lubricating Oil Analysis," programs or where the environment in the period of extended operation is expected to be equivalent to that in the prior 40 years and for which no aging effects have been observed. However, one-time inspection for environments that do not fall in the above category, or of any other action or program created to verify the effectiveness of an AMP and confirm the absence of an aging effect, is to be reviewed by the staff on a plant-specific basis.
December 201 0 XI M32-1 NUREG-1801, Rev. 2 OAG10001390_00651
This program cannot be used for structures or components with known age-related degradation mechanisms or when the environment in the period of extended operation is not expected to be equivalent to that in the prior 40 years. Periodic inspections should be proposed in these cases.
Evaluation and Technical Basis
- 1. Scope of Program: The scope of this program includes systems and components that are subject to aging management using the GALL AMPs XI.M2, "Water Chemistry"; XI.M30, "Fuel Oil Chemistry"; and XI.M39, "Lubricating Oil Analysis," and for which no aging effects have been observed or for which the aging effect is occurring very slowly and does not affect the component's or structure's intended function during the period of extended operation based on prior operating experience data. The scope of this program also may include other components and materials where the environment in the period of extended operation is expected to be equivalent to that in the prior 40 years and for which no aging effects have been observed.
The program cannot be used for structures or components subjected to known age-related degradation mechanisms or when the environment in the period of extended operation is not expected to be equivalent to that in the prior 40 years. Periodic inspections should be proposed in these cases.
- 2. Preventive Actions: One-time inspection is a condition monitoring program. It does not include methods to mitigate or prevent age-related degradation.
- 3. Parameters Monitored/Inspected: The program monitors parameters directly related to the age-related degradation of a component. Examples of parameters monitored and the related aging effect are provided in the table in Element 4, below. Inspection is performed using a variety of nondestructive examination (NDE) methods, including visual, volumetric, and surface techniques.
- 4. Detection of Aging Effects: Elements of the program include (a) determination of the sample size of components to be inspected based on an assessment of materials of fabrication, environment, plausible aging effects, and operating experience; (b) identification of the inspection locations in the system or component based on the potential for the aging effect to occur; and (c) determination of the examination technique, including acceptance criteria that would be effective in managing the aging effect for which the component is examined. Where practical, the inspection includes a representative sample of the system population and focuses on the bounding or lead components most susceptible to aging due to time in service, and severity of operating conditions. For components managed by the AMP XI.M2, Water Chemistry"; AMP XI.M30, "Fuel Oil Chemistry"; and AMP XI.M39, "Lubricating Oil Analysis," programs, a representative sample size is 20% of the population (defined as components having the same material, environment, and aging effect combination) or a maximum of 25 components. Otherwise, a technical justification of the methodology and sample size used for selecting components for one-time inspection should be included as part of the program's documentation.
The program relies on established NDE techniques, including visual, ultrasonic, and surface techniques. Inspections are performed by personnel qualified in accordance with site procedures and programs to perform the type of examination specified. For code components, examinations should follow procedures consistent with the American Society NUREG-1801, Rev. 2 XI M32-2 December 201 0 OAG10001390_00652
of Mechanical Engineers (ASME) Code 16 and 10 CFR Part 50, Appendix B. For non-code components, examinations should follow site procedures that include requirements for items such as lighting, presence of protective coatings, and cleaning processes that ensure an adequate examination. In addition, a description of Enhanced Visual Examination (EVT-1) is found in Boiling Water Reactor Vessel and Internals Project (BWRVIP)-03 and Materials Reliability Program (MRP)-228.
The inspection and test techniques shall have a demonstrated history of effectiveness in detecting the aging effect of concern. Typically, the one-time inspections shall be performed as indicated in the following table.
Examples of Parameters Monitored or Inspected and Aging Effect for Specific Structure or Component 17 Aging Parameter(s)
Aging Effect Inspection Method 18 Mechanism Monitored Loss of Material Crevice Surface Condition, Visual (VT-1 or equivalent) and/or Corrosion Wall Thickness Volumetric (ultrasonic testing [UT])
Loss of Material Galvanic Surface Condition, Visual (VT-3 or equivalent) and/or Corrosion Wall Thickness Volumetric (UT)
Loss of Material General Surface Condition, Visual (VT-3 or equivalent) and/or Corrosion Wall Thickness Volumetric (UT)
Loss of Material MIC Surface Condition, Visual (VT-3 or equivalent) and/or Wall Thickness Volumetric (UT)
Loss of Material Pitting Surface Condition, Visual (VT-1 or equivalent) and/or Corrosion Wall Thickness Volumetric (UT)
Loss of Material Erosion Surface Condition, Visual (VT-3 or equivalent) and/or Wall Thickness Volumetric (UT)
Reduction of Fouling Tube Fouling Visual (VT-3 or equivalent)
Heat Transfer Cracking SCCor Surface Condition, Enhanced Visual (EVT-1 or equivalent)
Cyclic Cracks or Surface Examination (magnetic Loading particle, liquid penetrant) or Volumetric (radiographic testing or UT)
With respect to inspection timing, the sample of components inspected before the end of the current operating term needs to be sufficient to provide reasonable assurance that the aging effect will not compromise any intended function during the period of extended operation.
Specifically, inspections need to be completed early enough to ensure that the aging effects that may affect intended functions early in the period of extended operation are appropriately managed. Conversely, inspections need to be timed to allow the inspected components to attain sufficient age to ensure that the aging effects with long incubation 16 Refer to the GALL Report, Chapter I, for application of other editions of the ASME Code,Section XI.
17 The examples provided in the table may not be appropriate for all relevant situations. If the applicant chooses to use an alternative to the recommendations in this table, a technical justification should be provided as an exception to this AMP. This exception should list the AMR line item component, examination technique, acceptance criteria, evaluation standard, and a description of the justification.
18 Visual inspection may be used only when the inspection methodology examines the surface potentially experiencing the aging effect.
December 201 0 XI M32-3 NUREG-1801, Rev. 2 OAG10001390_00653
periods (i.e., those that may affect intended functions near the end of the period of extended operation) are identified. Within these constraints, the applicant should schedule the inspection no earlier than 10 years prior to the period of extended operation and in such a way as to minimize the impact on plant operations. As a plant will have operated for at least 30 years before inspections under this program begin, sufficient time will have elapsed for any aging effects to be manifested.
- 5. Monitoring and Trending: This is a one-time inspection program. Monitoring and trending are not applicable.
- 6. Acceptance Criteria: Any indication or relevant conditions of degradation detected are evaluated. Acceptance criteria may be based on applicable ASME or other appropriate standards, design basis information, or vendor-specified requirements and recommendations. For example, ultrasonic thickness measurements are compared to predetermined limits.
- 7. Corrective Actions: Unacceptable inspection findings are evaluated in accordance with the site's corrective action process to determine appropriate corrective actions and the need for subsequent (including periodic) inspections under another AMP. Site quality assurance (QA) procedures, review and approval processes, and administrative controls are implemented in accordance with the requirements of 10 CFR Part 50, Appendix B. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions, confirmation process, and administrative controls.
- 8. Confirmation Process: Confirmation processes to ensure that preventive actions are adequate and that appropriate corrective actions have been completed and are effective are implemented through the site QA program in accordance with the requirements of 10 CFR Part 50, Appendix B.
- 9. Administrative Controls: Administrative controls to provide a formal review and approval for corrective actions are implemented through the site QA program in accordance with the requirements of 10 CFR Part 50, Appendix B.
- 10. Operating Experience: The elements that comprise inspections associated with this program (the scope of the inspections and inspection techniques) are consistent with industry practice. An applicant's operating experience with detection of aging effects should be adequate to demonstrate that the program is capable of detecting the presence or noting the absence of aging effects in the components, materials, and environments where one-time inspection is used to confirm system-wide effectiveness of another preventive or mitigative AMP.
References 10 CFR Part 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
10 CFR 50.55a, Codes and Standards, Office of the Federal Register, National Archives and Records Administration, 2009.
NUREG-1801, Rev. 2 XI M32-4 December 201 0 OAG10001390_00654
ASME Section XI, Rules for In service Inspection of Nuclear Power Plant Components, The ASME Boiler and Pressure Vessel Code, 2004 edition as approved in 10 CFR 50.55a, The American Society of Mechanical Engineers, New York, NY.
BWRVIP-03 (EPRI 105696- R6), BWR Vessel and Internals Project: Reactor Pressure Vessel and Internals Examination Guidelines, January 6, 2004, Final Safety Evaluation Report by the Office of Nuclear Reactor Regulation, June 2008.
MRP-228, Materials Reliability Program: Inspection Standard for PWR Internals, 2009.
December 201 0 XI M32-S NUREG-1801, Rev. 2 OAG10001390_00655
XI.M33 SELECTIVE LEACHING Program Description This program demonstrates the absence of selective leaching. The program for selective leaching of materials ensures the integrity of the components made of gray cast iron and copper alloys (except for inhibited brass) that contain greater than 15 percent zinc (> 15% Zn) or greater than 8 percent aluminum (>8% AI in the case of aluminum-bronze) exposed to a raw water, closed cooling water, treated water, or ground water environment that may lead to selective leaching of one of the metal components where there has not been previous experience of selective leaching. The AMP includes a one-time visual inspection of selected components that may be susceptible to selective leaching, coupled with either hardness measurements (where feasible, based on form and configuration) or mechanical examination techniques. These techniques can determine whether loss of materials due to selective leaching is occurring and whether selective leaching will affect the ability of the components to perform their intended function for the period of extended operation.
The selective leaching process involves the preferential removal of one of the alloying elements from the material, which leads to the enrichment of the remaining alloying elements.
Dezincification (loss of zinc from brass) and graphitization (removal of iron from cast iron) are examples of such a process. Susceptible materials, high temperatures, stagnant-flow conditions, and a corrosive environment, such as acidic solutions for brasses with high zinc content and dissolved oxygen, are conducive to selective leaching.
Although the program does not provide guidance on preventive action, it is noted that monitoring of water chemistry to control pH and concentration of corrosive contaminants and treatment to minimize dissolved oxygen in water are effective in reducing selective leaching.
Water chemistry is managed by the Water Chemistry program (AMP XI.M2).
Evaluation and Technical Basis
- 1. Scope of Program: This program demonstrates the absence of selective leaching. For materials and environments where selective leaching is currently occurring or for materials in environments where the component has been repaired with the same material, a plant-specific program is required. Components include piping, valve bodies and bonnets, pump casings, and heat exchanger components that are susceptible to selective leaching. The materials of construction for these components may include gray cast iron and uninhibited brass containing greater than 15% zinc. These components may be exposed to raw water, treated water, closed cooling water, ground water, water contaminated fuel oil, or water-contaminated lube oil.
- 2. Preventive Actions: This program is a condition monitoring program and it contains no preventive actions.
- 3. Parameters Monitored/Inspected: This program monitors selective leaching through the monitoring of surface hardness and visual appearance (color, porosity, abnormal surface conditions).
- 4. Detection of Aging Effects: The visual inspection and hardness measurement or other mechanical examination techniques, such as destructive testing (when the opportunity arises), chipping, or scraping, is a one-time inspection conducted within the last 5 years December 201 0 XI M33-1 NUREG-1801, Rev. 2 OAGI0001390_00656
prior to entering the period of extended operation. Because selective leaching is a slow acting corrosion process, this measurement is performed just prior to the period of extended operation. Follow-up of unacceptable inspection findings includes an evaluation using the corrective action program and a possible expansion of the inspection sample size and location.
Where practical, the inspection includes a representative sample of the system population and focuses on the bounding or lead components most susceptible to aging due to time in service, severity of operating conditions, and lowest design margin. Twenty percent of the population with a maximum sample of 25 constitutes a representative sample size.
Otherwise, a technical justification of the methodology and sample size used for selecting components for one-time inspection should be included as part of the program's documentation. Each group of components with different material/environment combinations is considered a separate population.
Selective leaching generally does not cause changes in dimensions and is difficult to detect by visual inspection. However, in certain brasses, it causes plug-type dezincification, which can be detected by visual inspection. One acceptable procedure is to visually inspect the susceptible components closely and conduct Brinell hardness testing (where feasible, based on form and configuration or other industry-accepted mechanical inspection techniques) on the inside surfaces of the selected set of components to determine if selective leaching has occurred. If selective leaching is apparent, an engineering evaluation is initiated to determine acceptability of the affected components for further service.
- 5. Monitoring and Trending: This is a one-time inspection to determine if selective leaching is an issue. Monitoring and trending is not required.
- 6. Acceptance Criteria: The acceptance criteria are no visible evidence of selective leaching or no more than a 20 percent decrease in hardness. For copper alloys with greater than 15 percent zinc, the criteria is no noticeable change in color from the normal yellow color to the reddish copper color.
- 7. Corrective Actions: Engineering evaluations are performed for test or inspection results that do not satisfy established acceptance criteria. The corrective actions program ensures that conditions adverse to quality are promptly corrected. If the deficiency is assessed to be significantly adverse to quality, the cause of the condition is determined and an action plan is developed to preclude repetition. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions. Unacceptable inspection findings result in additional inspection(s) being performed, which may be on a periodic basis, or in component repair or replacement.
- 8. Confirmation Process: Site quality assurance (QA) procedures, review and approval processes, and administrative controls are implemented in accordance with the requirements of 10 CFR Part 50, Appendix B. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the confirmation process and administrative controls.
- 9. Administrative Controls: The administrative controls for this program provide for a formal review and approval of corrective actions. The administrative controls for this program are implemented through the site's QA program in accordance with the requirements of 10 CFR Part 50, Appendix B.
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- 10. Operating Experience: The elements that comprise these inspections (e.g., the scope of the inspections and inspection techniques) are consistent with industry practice and staff expectations. Selective leaching has been detected in components constructed from cast iron, brass, bronze, and aluminum bronze. Components affected have included valve bodies, pump casings, piping, and cast iron fire protection piping buried in soil.
References 10 CFR Part 50, Appendix 8, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
EPRI TR-107514, Age Related Degradation Inspection Method and Demonstration, Electric Power Research Institute, April 1998.
Fontana, M. G., Corrosion Engineering, McGraw Hill, p 86-90, 1986.
NUREG-1705, Safety Evaluation Report Related to the License Renewal of Calvert Cliffs Nuclear Power Plant, Units 1 and 2, U.S. Nuclear Regulatory Commission, December 1999.
NUREG-1723, Safety Evaluation Report Related to the License Renewal of Oconee Nuclear Station, Units 1, 2, and 3, U.S. Nuclear Regulatory Commission, March 2000.
NUREG-1930, Safety Evaluation Report Related to the License Renewal of Indian Point Nuclear Generating Units 2 and 3, U.S. Nuclear Regulatory Commission, November 2009.
Schweitzer, P. A., Encyclopedia of Corrosion Technology 2nd Ed, Marcel Dekker, p 201-202.
March 17,2004.
December 201 0 XI M33-3 NUREG-1801, Rev. 2 OAG10001390_00658
XI.M35 ONE-TIME INSPECTION OF ASME CODE CLASS 1 SMALL-BORE PIPING Program Description This program augments the requirements in American Society of Mechanical Engineers (ASME)
Code,Section XI, 2004 edition19, and is applicable to small-bore ASME Code Class 1 piping and systems less than 4 inches nominal pipe size (less than NPS 4) and greater than or equal to NPS 1. The program includes pipes, fittings, branch connections, and all full and partial penetration (socket) welds.
According to Table IW8-2500-1, Examination Category 8-J, Item No. 89.21 and 89.40 of the current ASME Code, an external surface examination of small-bore Class 1 piping should be included for piping less than NPS 4. Other ASME Code provisions exempt from examination piping NPS 1 and smaller. This program is augmented to include piping from NPS 1 to less than NPS 4. Also, Examination Category 8-P requires system leakage of all Class 1 piping.
However, the staff believes that for a one-time inspection to detect cracking resulting from thermal and mechanical loading or intergranular stress corrosion of full-penetration welds, the inspection should be a volumetric examination. For a one-time inspection to detect cracking in socket welds, the inspection should be either a volumetric or opportunistic destructive examination. (Opportunistic destructive examination is performed when a weld is removed from service for other considerations, such as plant modifications. A sampling basis is used if more than 1 weld is removed.) These examinations provide additional assurance that either aging of small-bore ASM E Code Class 1 piping is not occurring or the aging is insignificant, such that a plant-specific aging management program (AMP) is not warranted.
This program is applicable to systems that have not experienced cracking of ASME Code Class 1 small-bore piping. This program can also be used for systems that experienced cracking but have implemented design changes to effectively mitigate cracking. (Measure of effectiveness includes (1) the one-time inspection sampling is statistically significant;(2) samples will be selected as described in Element 5, Monitoring and Trending below; and (3) no repeated failures over an extended period of time.) For systems that have experienced cracking and operating experience indicates that design changes have not been implemented to effectively mitigate cracking, periodic inspection is proposed, as managed by a plant-specific AMP. Should evidence of cracking be revealed by a one-time inspection, periodic inspection is implemented using a plant-specific AMP.
If small bore piping in a particular plant system has experienced cracking, small bore piping in all plant systems are evaluated to determine whether the cause for the cracking affects other systems (corrective action program).
Evaluation and Technical Basis
- 1. Scope of Program: This program is a one-time inspection of a sample of ASME Code Class 1 piping less than NPS 4 and greater than or equal to NPS 1. This program includes measures to verify that degradation is not occurring, thereby either confirming that there is no need to manage age-related degradation or validating the effectiveness of any existing AMP for the period of extended operation. The one-time inspection program for ASME Code Class 1 small-bore piping includes locations that are susceptible to cracking.
19 Refer to the GALL Report, Chapter I, for applicability of other editions of the ASME Code,Section XI.
December 201 0 XI M35-1 NUREG-1801, Rev. 2 OAG10001390_00659
- 2. Preventive Actions: This program is a condition monitoring activity independent of methods to mitigate or prevent degradation.
- 3. Parameters Monitored/Inspected: This inspection detects cracking in ASME Code Class 1 small-bore piping.
- 4. Detection of Aging Effects: This one-time inspection is designed to provide assurance that aging of ASME Code Class 1 small-bore piping is not occurring, or that the effects of aging are not significant. This inspection does not apply to those plants that have experienced cracking due to stress corrosion, cyclical (including thermal, mechanical, and vibration fatigue) loading, or thermal stratification and thermal turbulence (MRP 146 and MRP 146S).
For a one-time inspection to detect cracking in socket welds, the inspection should be either a volumetric or opportunistic destructive examination. (Opportunistic destructive examination is performed when a weld is removed from service for other considerations, such as plant modifications. A sampling basis is used if more than one weld is removed.) For a one-time inspection to detect cracking resulting from thermal and mechanical loading or intergranular stress corrosion of full penetration welds, the inspection should be a volumetric examination.
Volumetric examination is performed using demonstrated techniques that are capable of detecting the aging effects in the examination volume of interest. This inspection should be performed at a sufficient number of locations to ensure an adequate sample. This number, or sample size, is based on susceptibility, inspectability, dose considerations, operating experience, and limiting locations of the total population of ASME Code Class 1 small-bore piping locations.
If an applicant has never experienced a failure in its ASME Code Class 1 piping (a through-wall crack detected in the subject component by evidence of leakage, or through nondestructive or destructive examination) and has extensive operating history (more than 30 years of operation at time of submitting the application), the inspection sample size should be at least 3% of the weld population or a maximum of 10 welds of each weld type for each operating unit. If the applicant has successfully mitigated any failures in its ASME Class 1 piping, the inspection should include 10% of the weld population or a maximum of 25 welds of each weld type (e.g., full penetration or socket weld) for each operating unit using a methodology to select the most susceptible and risk-significant welds. For socket welds, opportunistic destructive examination can be performed in lieu of volumetric examination. Because more information can be obtained from a destructive examination than from nondestructive examination, the applicant may take credit for each weld destructively examined equivalent to having volumetrically examined two welds.
The one time inspection should be completed within the six year period prior to the period of extended operation.
- 5. Monitoring and Trending: This is a one-time inspection to determine whether cracking in ASME Code Class 1 small-bore piping resulting from stress corrosion, cyclical (including thermal, mechanical, and vibration fatigue) loading, or thermal stratification and thermal turbulence (MRP 146 and MRP 146S) is an issue. Evaluation of the inspection results may indicate the need for additional or periodic examinations (i.e., a plant-specific AMP for Class 1 small-bore piping using volumetric inspection methods consistent with ASME Code,Section XI, Subsection IWB).
- 6. Acceptance Criteria: If flaws or indications exceed the acceptance criteria of ASME Code,Section XI, Paragraph IWB-3400, they are evaluated in accordance with ASME Code, NUREG-1801, Rev. 2 XI M35-2 December 201 0 OAG10001390_00660
Section XI, Paragraph IWB-3131; additional examinations are performed in accordance with ASME Code,Section XI, Paragraph IWB-2430. Evaluation of flaws identified during a volumetric examination of socket welds should be in accordance with IWB-3600.
- 7. Corrective Actions: The site corrective action program, quality assurance procedures, site review and approval process, and administrative controls are implemented in accordance with the requirements of 10 CFR Part 50, Appendix B. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions, confirmation process, and administrative controls. Should evidence of cracking be revealed by a one-time inspection, periodic inspection is implemented, as managed by a plant-specific AMP.
- 8. Confirmation Process: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the confirmation process.
- 9. Administrative Controls: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the administrative controls.
- 10. Operating Experience: This inspection uses volumetric inspection techniques with demonstrated capability and a proven industry record to detect cracking in piping weld and base material.
References 10 CFR Part 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
10 CFR 50.55a, Codes and Standards, Office of the Federal Register, National Archives and Records Administration, 2009.
ASME Section XI, Rules for In service Inspection of Nuclear Power Plant Components, The ASME Boiler and Pressure Vessel Code, 2004 edition as approved in 10 CFR 50.55a, The American Society of Mechanical Engineers, New York, NY.
EPRI 1011955, Materials Reliability Program: Management of Thermal Fatigue in Normally Stagnant Non-Iso/able Reactor Coolant System Branch Lines (MRP-146), June 8,2005.
EPRI 1018330, Materials Reliability Program: Management of Thermal Fatigue in Normally Stagnant Non-Iso/able Reactor Coolant System Branch Lines - Supplemental Guidance (MRP-146S), December 31,2008.
NRC Information Notice 97-46, Uniso/able Crack in High-Pressure Injection Piping, U.S. Nuclear Regulatory Commission, July 9, 1997.
December 201 0 XI M35-3 NUREG-1801, Rev. 2 OAG10001390_00661
XI.M36 EXTERNAL SURFACES MONITORING OF MECHANICAL COMPONENTS Program Description The External Surfaces Monitoring of Mechanical Components program is based on system inspections and walkdowns. This program consists of periodic visual inspections of metallic and polymeric components, such as piping, piping components, ducting, polymeric components, and other components within the scope of license renewal and subject to aging management review (AMR) in order to manage aging effects. The program manages aging effects through visual inspection of external surfaces for evidence of loss of material, cracking, and change in material properties. When appropriate for the component and material, manipulation may be used to augment visual inspection to confirm the absence of elastomer hardening and loss of strength.
Loss of material due to boric acid corrosion is managed by the Boric Acid Corrosion program (AMP XI.M10).
Evaluation and Technical Basis
- 1. Scope of Program: This program visually inspects the external surface of in-scope mechanical components and monitors external surfaces of metallic components in systems within the scope of license renewal and subject to AMR for loss of material and leakage.
Cracking of stainless steel components exposed to an air environment containing halides may also be managed. This program also visually inspects and monitors the external surfaces of polymeric components in mechanical systems within the scope of license renewal and subject to AMR for changes in material properties (such as hardening and loss of strength), cracking, and loss of material due to wear. This program manages the effects of aging of polymer materials in all environments to which these materials are exposed.
The program may also be credited with managing loss of material from internal surfaces of metallic components and with loss of material, cracking, and change in material properties from the internal surfaces of polymers, for situations in which material and environment combinations are the same for internal and external surfaces such that external surface condition is representative of internal surface condition. When credited, the program should describe the component internal environment and the credited similar external component environment inspected.
- 2. Preventive Actions: The External Surfaces Monitoring of Mechanical Components program is a condition monitoring program that does not include preventive actions.
- 3. Parameters Monitored/Inspected: The External Surfaces Monitoring of Mechanical Components program utilizes periodic plant system inspections and walkdowns to monitor for material degradation and leakage. This program inspects components such as piping, piping components, ducting, polymeric components, and other components. For metallic components, coatings deterioration is an indicator of possible underlying degradation. The aging effects for flexible polymeric components may be monitored through a combination of visual inspection and manual or physical manipulation of the material. "Manual or physical manipulation of the material" means touching, pressing on, flexing, bending, or otherwise manually interacting with the material. The purpose of the manual manipulation is to reveal changes in material properties, such as hardness, and to make the visual examination process more effective in identifying aging effects such as cracking.
Examples of inspection parameters for metallic components include:
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- corrosion and material wastage (loss of material)
- leakage from or onto external surfaces (loss of material)
- worn, flaking, or oxide-coated surfaces (loss of material)
- corrosion stains on thermal insulation (loss of material)
- protective coating degradation (cracking, flaking, and blistering)
- leakage for detection of cracks on the external surfaces of stainless steel components exposed to an air environment containing halides Examples of inspection parameters for polymers include:
- surface cracking, crazing, scuffing, and dimensional change (e.g., "ballooning" and "necking")
- discoloration
- 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
- 4. Detection of Aging Effects: This program manages aging effects of loss of material, cracking, and change in material properties using visual inspection. For coated surfaces, confirmation of the integrity of the paint or coating is an effective method for managing the effects of corrosion on the metallic surface.
When required by the ASME Code, inspections are conducted in accordance with the applicable code requirements. In the absence of applicable code requirements, plant-specific visual inspections are performed of metallic and polymeric component surfaces using plant-specific procedures implemented by inspectors qualified through plant-specific programs. The inspections are capable of detecting age-related degradation and are performed at a frequency not to exceed one refueling cycle. This frequency accommodates inspections of components that may be in locations that are normally only accessible during outages or access is physically restricted (underground). Surfaces that are not readily visible during plant operations and refueling outages are inspected when they are made accessible and at such intervals that would ensure the components' intended functions are maintained.
The inspections of underground components shall be conducted during each 1O-year period beginning 10 years prior to entering the period of extended operation. These normally underground components should be clearly identified in the program scope and inspection intervals provided. Surfaces that are insulated may be inspected when the external surface is exposed (i.e., during maintenance) at such intervals that would ensure that the components' intended functions are maintained. The intervals of inspections may be adjusted, as necessary, based on plant-specific inspection results and industry operating experience.
Visual inspection will identify indirect indicators of flexible polymer hardening and loss of strength and include the presence of surface cracking, crazing, discoloration, and, for NUREG-1801, Rev. 2 XI M36-2 December 201 0 OAG10001390_00663
elastomers with internal reinforcement, the exposure of reinforcing fibers, mesh, or underlying metal. Visual inspection should be 100% of accessible components. Visual inspection will identify direct indicators of loss of material due to wear to include dimensional change, scuffing, and for flexible polymeric materials with internal reinforcement, the exposure of reinforcing fibers, mesh, or underlying metal. Manual or physical manipulation can be used to augment visual inspection to confirm the absence of hardening and loss of strength for flexible polymeric materials (e.g., HVAC flexible connectors) where appropriate.
The sample size for manipulation should be at least 10 percent of available surface area.
Hardening and loss of strength and loss of material due to wear for flexible polymeric materials are expected to be detectable prior to any loss of intended function.
This program is credited with managing the following aging effects.
- loss of material and cracking for external surfaces
- loss of material for internal surfaces exposed to the same environment as the external surface
- cracking and change in material properties (hardening and loss of strength) of flexible polymers
- 5. Monitoring and Trending: Visual inspection and manual or physical manipulation activities are performed and associated personnel are qualified in accordance with site controlled procedures and processes. The External Surfaces Monitoring of Mechanical Components program uses standardized monitoring and trending activities to track degradation.
Deficiencies are documented using approved processes and procedures, such that results can be trended. However, the program does not include formal trending. Inspections are performed at frequencies identified in Element 4, Detection of Aging Effects.
- 6. Acceptance Criteria: For each component/aging effect combination, the acceptance criteria are defined to ensure that the need for corrective actions will be identified before loss of intended functions. For metallic surfaces, any indications of relevant degradation detected are evaluated. For stainless steel surfaces, a clean, shiny surface is expected. The appearance of discoloration may indicate the loss of material on the stainless steel surface.
For aluminum and copper alloys exposed to marine or industrial environments, any indications of relevant degradation that could impact their intended function are evaluated.
For flexible polymers, a uniform surface texture and uniform color with no unanticipated dimensional change is expected. Any abnormal surface condition may be an indication of an aging effect for metals and for polymers. For flexible materials, changes in physical properties (e.g., the hardness, flexibility, physical dimensions, and color of the material are unchanged from when the material was new) should be evaluated for continued service in the corrective action program. Cracks should be absent within the material. For rigid polymers, surface changes affecting performance, such as erosion, cracking, crazing, checking, and chalking, are subject to further investigation. Acceptance criteria include design standards, procedural requirements, current licensing basis, industry codes or standards, and engineering evaluation.
- 7. Corrective Actions: Site quality assurance procedures, review and approval processes, and administrative controls are implemented in accordance with the requirements of 10 CFR Part 50, Appendix B. As discussed in the Appendix for GALL, the staff finds the December 201 0 XI M36-3 NUREG-1801, Rev. 2 OAG10001390_00664
requirements of 10 CFR Part 50, Appendix 8, acceptable to address the corrective actions, confirmation process, and administrative controls.
- 8. Confirmation Process: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the confirmation process.
- 9. Administrative Controls: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the administrative controls.
- 10. Operating Experience: External surface inspections through system inspections and walkdowns have been in effect at many utilities since the mid 1990s in support of the Maintenance Rule (10 CFR 50.65) and have proven effective in maintaining the material condition of plant systems. The elements that comprise these inspections (e.g., the scope of the inspections and inspection techniques) are consistent with industry practice.
References 10 CFR Part 50, Appendix 8, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
EPRI Technical Report 1007933, Aging Assessment Field Guide, December 2003.
EPRI Technical Report 1009743, Aging Identification and Assessment Checklist, August 27, 2004.
INPO Good Practice TS-413, Use of System Engineers, INPO 85-033, May 18, 1988.
NUREG-1801, Rev. 2 XI M36-4 December 201 0 OAG10001390_00665
XI.M37 FLUX THIMBLE TUBE INSPECTION Program Description The Flux Thimble Tube Inspection is a condition monitoring program used to inspect for thinning of the flux thimble tube wall, which provides a path for the incore neutron flux monitoring system detectors and forms part of the reactor coolant system (RCS) pressure boundary. Flux thimble tubes are subject to loss of material at certain locations in the reactor vessel where flow-induced fretting causes wear at discontinuities in the path from the reactor vessel instrument nozzle to the fuel assembly instrument guide tube. A nondestructive examination methodology, such as eddy current testing (ECT) or other applicant-justified and U.S. Nuclear Regulatory Commission (NRC)-accepted inspection method, is used to monitor for wear of the flux thimble tubes. This program implements the recommendations of NRC IE Bulletin 88-09, as described below.
Evaluation and Technical Basis
- 1. Scope of Program: The flux thimble tube inspection encompasses all of the flux thimble tubes that form part of the RCS pressure boundary. The instrument guide tubes are not in the scope of this program. Within scope are the licensee responses to IE Bulletin 88-09, as accepted by the staff in its closure letters on the bulletin, and any amendments to the licensee responses as approved by the staff.
- 2. Preventive Actions: The program consists of inspection and evaluation and provides no guidance on preventive actions.
- 3. Parameters Monitored/Inspected: Flux thimble tube wall thickness is monitored to detect loss of material from the flux thimble tubes during the period of extended operation.
- 4. Detection of Aging Effects: An inspection methodology (such as ECT) that has been demonstrated to be capable of adequately detecting wear of the flux thimble tubes is used to detect loss of material during the period of extended operation. Justification for methods other than ECT should be provided unless use of the alternative method has been previously accepted by the NRC.
Examination frequency is based upon actual plant-specific wear data and wear predictions that have been technically justified as providing conservative estimates of flux thimble tube wear. The interval between inspections is established such that no flux thimble tube is predicted to incur wear that exceeds the established acceptance criteria before the next inspection. The examination frequency may be adjusted based on plant-specific wear projections. Rebaselining of the examination frequency should be justified using plant-specific wear-rate data unless prior plant-specific NRC acceptance for the re-baselining is received outside the license renewal process. If design changes are made to use more wear-resistant thimble tube materials (e.g., chrome-plated stainless steel), sufficient inspections are conducted at an adequate inspection frequency, as described above, for the new materials.
- 5. Monitoring and Trending: Flux thimble tube wall thickness measurements are trended and wear rates are calculated based on plant-specific data. Wall thickness is projected using plant-specific data and a methodology that includes sufficient conservatism to ensure that wall thickness acceptance criteria continue to be met during plant operation between scheduled inspections.
December 201 0 XI M37-1 NUREG-1801, Rev. 2 OAG10001390_00666
- 6. Acceptance Criteria: Appropriate acceptance criteria, such as percent through-wall wear, are established, and inspection results are evaluated and compared with the acceptance criteria. The acceptance criteria are technically justified to provide an adequate margin of safety to ensure that the integrity of the reactor coolant system pressure boundary is maintained. The acceptance criteria include allowances for factors such as instrument uncertainty, uncertainties in wear scar geometry, and other potential inaccuracies, as applicable, to the inspection methodology chosen for use in the program. Acceptance criteria different from those previously documented in the applicant's response to IE Bulletin 88-09 and amendments thereto, as accepted by the NRC, should be justified.
- 7. Corrective Actions: Flux thimble tubes with wall thickness that do not meet the established acceptance criteria are isolated, capped, plugged, withdrawn, replaced, or otherwise removed from service in a manner that ensures the integrity of the reactor coolant system pressure boundary is maintained. Analyses may allow repositioning of flux thimble tubes that are approaching the acceptance criteria limit. Repositioning of a tube exposes a different portion of the tube to the discontinuity that is causing the wear.
Flux thimble tubes that cannot be inspected over the tube length, that are subject to wear due to restriction or other defects, and that cannot be shown by analysis to be satisfactory for continued service are removed from service to ensure the integrity of the reactor coolant system pressure boundary.
The site corrective actions program, quality assurance procedures, site review and approval process, and administrative controls are implemented in accordance with 10 CFR Part 50, Appendix B. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions, confirmation process, and administrative controls.
- 8. Confirmation Process: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B acceptable to address the confirmation process.
- 9. Administrative Controls: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B acceptable to address the administrative controls.
- 10. Operating Experience: In IE Bulletin 88-09 the NRC requested that licensees implement a flux thimble tube inspection program due to several instances of leaks and due to licensees identifying wear. Utilities established inspection programs in accordance with IE Bulletin 88-09, which have shown excellent results in identifying and managing wear of flux thimble tubes.
As discussed in IE Bulletin 88-09, the amount of vibration the thimble tubes experience is determined by many plant-specific factors. Therefore, the only effective method for determining thimble tube integrity is through inspections, which are adjusted to account for plant-specific wear patterns and history.
References 10 CFR Part 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
NUREG-1801, Rev. 2 XI M37-2 December 201 0 OAG10001390_00667
NRC IE Bulletin 88-09, Thimble Tube Thinning in Westinghouse Reactors, July 26, 1988.
NRC Information Notice No. 87-44, Thimble Tube Thinning in Westinghouse Reactors, September 16, 1987.
NRC Information Notice No. 87-44, Supplement 1, Thimble Tube Thinning in Westinghouse Reactors, March 28, 1988.
December 201 0 XI M37-3 NUREG-1801, Rev. 2 OAG10001390_00668
XI.M38 INSPECTION OF INTERNAL SURFACES IN MISCELLANEOUS PIPING AND DUCTING COMPONENTS Program Description The program consists of inspections of the internal surfaces of metallic piping, piping components, ducting, polymeric components, and other components that are exposed to air-indoor uncontrolled, air outdoor, condensation, and any water system other than open-cycle cooling water system (XI.M20), closed treated water system (XI.M21A), and fire water system (XI.M27). 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 to ensure that existing environmental conditions are not causing material degradation that could result in a loss of component intended functions. For certain materials, such as polymers, physical manipulation or pressurization (e.g., hydrotesting) to detect hardening or loss of strength should be used to augment the visual examinations conducted under this program. If visual inspection of internal surfaces is not possible, then the applicant needs to provide a plant-specific program.
This program is not intended for use on piping and ducts where repetitive failures have occurred from loss of material that resulted in loss of intended function. If operating experience indicates that there have been repetitive failures caused by loss of material, a plant-specific program will be required. Following a failure, this program may be used if the failed material is replaced by one that is more corrosion-resistant in the environment of interest.
Evaluation and Technical Basis
- 1. Scope of Program: For metallic components, the program calls for the visual inspection of the internal surface of in-scope components that are not included in other aging management programs for loss of material. For metallic components with polymeric liners or for polymeric and elastomeric components, the program includes visual inspections of the internal polymer surfaces when coupled with additional augmented techniques, such as manipulation or pressurization. This program also includes metallic piping with or without polymeric linings, piping elements, ducting, and components in an internal environment. The program also calls for visual inspection and monitors the internal surfaces of polymeric and elastomeric components in mechanical systems for hardening and loss of strength, cracking, and for loss of material due to wear. The program manages the effects of aging of polymer materials in all environments to which these materials are exposed. 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 piping and ducts where failures have occurred from loss of material from corrosion.
- 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/Inspected: Parameters monitored or inspected include visible evidence of loss of material in metallic components.
This program manages loss of material and possible changes in material properties. This program monitors for evidence of surface discontinuities. For changes in material properties, December 201 0 XI M38-1 NUREG-1801, Rev. 2 OAGI0001390_00669
the visual examinations are supplemented, so changes in the properties are readily observable.
Examples of inspection parameters for metallic components include the following:
- corrosion and material parameters wastage (loss of material)
- leakage from or onto internal surfaces (loss of material)
- worn, flaking, or oxide-coated surfaces (loss of material)
Examples of inspection parameters for polymers are as follows:
- surface cracking, crazing, scuffing, and dimensional change (e.g., "ballooning" and "necking")
- discoloration
- 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
- 4. Detection of Aging Effects: Visual and mechanical inspections conducted under this program are opportunistic in nature; they are conducted whenever piping or ducting are opened for any reason. Visual inspections should include all accessible surfaces. Unless otherwise required (e.g., by the ASME code) all inspections should be carried out using plant-specific procedures by inspectors qualified through plant specific programs. The inspection procedures utilized must be capable of detecting the aging effect(s) under consideration. These inspections provide for the detection of aging effects prior to 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 rei nforcement.
Manual or physical manipulation 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 available 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 prior to any loss of intended function.
- 5. Monitoring and Trending: The Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components program uses standardized monitoring and trending activities to track degradation. Deficiencies are documented using approved processes and procedures such NUREG-1801, Rev. 2 XI M38-2 December 201 0 OAG10001390_00670
that results can be trended. However, the program does not include formal trending.
Inspections are performed at frequencies identified in Element 4, Detection of Aging Effects.
- 6. Acceptance Criteria: For each component/aging effect combination, the acceptance criteria are defined to ensure that the need for corrective actions is identified before loss of intended functions. For metallic surfaces, any indications of relevant degradation detected are evaluated. For stainless steel surfaces, a clean, shiny surface is expected. Discoloration may indicate the loss of material on the stainless steel surface. Any abnormal surface condition may be an indication of an aging effect for metals.
For flexible polymers, a uniform surface texture and uniform color with no unanticipated dimensional change is expected. Any abnormal surface condition may be an indication of an aging effect for metals and for polymers. For flexible materials to be considered acceptable, the inspection results should indicate that the flexible polymer material is in "as new" condition (e.g., the hardness, flexibility, physical dimensions, and color of the material are unchanged from when the material was new). Cracks should be absent within the material.
For rigid polymers, surface changes affecting performance, such as erosion, cracking, crazing, checking, and chalks, are subject to further investigation.
Acceptance criteria include design standards, procedural requirements, current licensing basis, industry codes or standards, and engineering evaluation.
- 7. Corrective Actions: The site corrective actions program, quality assurance procedures, site review and approval process, and administrative controls are implemented in accordance with the requirements of 10 CFR Part 50, Appendix B. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions, confirmation process, and administrative controls.
- 8. Confirmation Process: As discussed in the GALL Report, the staff finds the requirements 10 CFR Part 50, Appendix B, acceptable to address the confirmation process.
- 9. Administrative Controls: As discussed in the GALL Report, the staff finds the requirements 10 CFR Part 50, Appendix B, acceptable to address the administrative controls.
- 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. However, because the inspection frequency is plant-specific and depends on the plant operating experience, the applicant's plant-specific operating experience or applicable generic operating experience is further evaluated for the period of extended operation. The applicant evaluates recent operating experience and provides objective evidence to support the conclusion that the effects of aging are adequately managed.
December 201 0 XI M38-3 NUREG-1801, Rev. 2 OAG10001390_00671
References 10 CFR Part 50, Appendix 8, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
EPRI Technical Report 1007933, Aging Assessment Field Guide, December 2003.
EPRI Technical Report 1009743, Aging Identification and Assessment Checklist, August 27, 2004.
INPO Good Practice TS-413, Use of System Engineers, INPO 85-033, May 18, 1988.
NUREG-1801, Rev. 2 XI M38-4 December 201 0 OAG10001390_00672
XI.M39 LUBRICATING OIL ANALYSIS Program Description The purpose of the Lubricating Oil Analysis program is to ensure that the oil environment in the mechanical systems is maintained to the required quality to prevent or mitigate age-related degradation of components within the scope of this program. This program maintains oil systems contaminants (primarily water and particulates) within acceptable limits, thereby preserving an environment that is not conducive to loss of material or reduction of heat transfer.
Lubricating oil testing activities include sampling and analysis of lubricating oil for detrimental contaminants. The presence of water or particulates may also be indicative of inleakage and corrosion product buildup.
Although primarily a sampling program, the lubricating oil analysis program is generally effective in monitoring and controlling impurities. This report identifies when the program is to be augmented to manage the effects of aging for license renewal. Accordingly, in certain cases identified in this report, verification of the effectiveness of the program is undertaken to ensure that significant degradation is not occurring and that the component's intended function is maintained during the period of extended operation. For these specific cases, an acceptable verification program is a one-time inspection of selected components at susceptible locations in the system.
Evaluation and Technical Basis
- 1. Scope of Program: The program manages the aging effects of loss of material due to corrosion or reduction of heat transfer due to fouling. Components within the scope of the program include piping, piping components, and piping elements; heat exchanger tubes; reactor coolant pump elements; and any other plant components subject to aging management review that are exposed to an environment of lubricating oil (including non-water-based hydraulic oils).
- 2. Preventive Actions: The Lubricating Oil Analysis program maintains oil system contaminants (primarily water and particulates) within acceptable limits.
- 3. Parameters Monitored/Inspected: This program performs a check for water and a particle count to detect evidence of contamination by moisture or excessive corrosion.
- 4. Detection of Aging Effects: Moisture or corrosion products increase the potential for, or may be indicative of, loss of material due to corrosion and reduction of heat transfer due to fouling. The program performs periodic sampling and testing of lubricating oil for moisture and corrosion particles in accordance with industry standards. The program recommends sampling and testing of the old oil following periodic oil changes or on a schedule consistent with equipment manufacturer's recommendations or industry standards (e.g., American Society for Testing of Materials [ASTM] 0 6224-02). Plant-specific operating experience also may be used to augment manufacturer's recommendations or industry standards in determining the schedule for periodic sampling and testing when justified by prior sampling results.
In certain cases, as identified by the AMR Items in this report, inspection of selected components is to be undertaken to verify the effectiveness of the program and to ensure December 201 0 XI M39-1 NUREG-1801, Rev. 2 OAG10001390_00673
that significant degradation is not occurring and that the component intended function is maintained during the period of extended operation.
- 5. Monitoring and Trending: Oil analysis results are reviewed to determine if alert levels or limits have been reached or exceeded. This review also checks for unusual trends.
- 6. Acceptance Criteria: Water and particle concentration should not exceed limits based on equipment manufacturer's recommendations or industry standards. Phase-separated water in any amount is not acceptable.
- 7. Corrective Actions: Pursuant to 10 CFR Part 50, Appendix B, specific corrective actions are implemented in accordance with the plant quality assurance (QA) program. For example, if a limit is reached or exceeded, actions to address the condition are taken. These may include increased monitoring, corrective maintenance, further laboratory analysis, and engineering evaluation of the system. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions.
- 8. Confirmation Process: Site QA procedures, review and approval processes, and administrative controls are implemented in accordance with the requirements of 10 CFR Part 50, Appendix B. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the confirmation process and administrative controls.
- 9. Administrative Controls: The administrative controls for this program provide for a formal review and approval of corrective actions. The administrative controls for this program are implemented through the site's QA program in accordance with the requirements of 10 CFR Part 50, Appendix B.
- 10. Operating Experience: The operating experience at some plants has identified (a) water in the lubricating oil and (b) particulate contamination. However, no instances of component failures attributed to lubricating oil contamination have been identified.
References 10 CFR Part 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
ASTM 0 6224-02, Standard Practice for In-Service Monitoring of Lubricating Oil for Auxiliary Power Plant Equipment, American Society of Testing Materials, West Conshohocken, PA, 2002.
NUREG-1801, Rev. 2 XI M39-2 December 201 0 OAG10001390_00674
XI.M40 MONITORING OF NEUTRON-ABSORBING MATERIALS OTHER THAN BORAFLEX Program Description A monitoring program is implemented to assure that degradation of the neutron-absorbing material used in spent fuel pools that could compromise the criticality analysis will be detected.
The applicable aging management program (AMP) relies on periodic inspection, testing, monitoring, and analysis of the criticality design to assure that the required 5% sub-criticality margin is maintained during the period of license renewal.
Evaluation and Technical Basis
- 1. Scope of Program: The AMP manages the effects of aging on neutron-absorbing components/materials used in spent fuel racks.
- 2. Preventive Actions: This AMP is a condition monitoring program, and therefore, there are no preventative actions.
- 3. Parameters Monitored/Inspected: For these materials, gamma irradiation and/or long-term exposure to the wet pool environment may cause loss of material and changes in dimension (such as gap formation, formation of blisters, pits and bulges) that could result in loss of neutron-absorbing capability of the material. The parameters monitored include the physical condition of the neutron-absorbing materials, such as in-situ gap formation, geometric changes in the material (formation of blisters, pits, and bulges) as observed from coupons or in situ, and decreased boron areal density, etc. The parameters monitored are directly related to determination of the loss of material or loss of neutron absorption capability of the material(s).
- 4. Detection of Aging Effects: The loss of material and the degradation of the neutron-absorbing material capacity are determined through coupon and/or direct in-situ testing.
Such testing should include periodic verification of boron loss through areal density measurement of coupons or through direct in-situ techniques, which may include measurement of boron areal density, geometric changes in the material (blistering, pitting, and bulging), and detection of gaps through blackness testing. The frequency of the inspection and testing depends on the condition of the neutron-absorbing material and is determined and justified with plant-specific operating experience by the licensee, not to exceed 10 years.
- 5. Monitoring and Trending: The measurements from periodic inspections and analysis are compared to baseline information or prior measurements and analysis for trend analysis.
The approach for relating the measurements to the performance of the spent fuel neutron absorber materials is specified by the applicant, considering differences in exposure conditions, vented/non-vented test samples, and spent fuel racks, etc.
- 6. Acceptance Criteria: Although the goal is to ensure maintenance of the 5% sub-criticality margin for the spent fuel pool, the specific acceptance criteria for the measurements and analyses are specified by the applicant.
- 7. Corrective Actions: Corrective actions are initiated if the results from measurements and analysis indicate that the 5% sub-criticality margin cannot be maintained because of December 201 0 XI M40-1 NUREG-1801, Rev. 2 OAGI0001390_00675
current or projected future degradation of the neutron-absorbing material. Corrective actions may consist of providing additional neutron-absorbing capacity with an alternate material, or applying other options, which are available to maintain the sub-criticality margin. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions.
- 8. Confirmation Process: Site quality assurance (QA) procedures, site review and approval processes, and administrative controls are implemented in accordance with the requirements of 10 CFR Part 50, Appendix B. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B acceptable to address the confirmation process and administrative controls.
- 9. Administrative Controls: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address administrative controls.
- 10. Operating Experience: Applicants for license renewal reference plant-specific operating experience and industry experience to provide reasonable assurance that the program is able to detect degradation of the neutron absorbing material in the applicant's spent fuel pool. Some of the industry operating experience that should be included is listed below:
- 1. Loss of material from the neutron absorbing material has been seen at many plants, including loss of aluminum, which was detected by monitoring the aluminum concentration in the spent fuel pool. One instance of this was documented in the Vogtle LRA Water Chemistry Program B.3.28.
- 2. Blistering has also been noted at many plants. Examples include blistering at Seabrook and Beaver Valley.
- 3. The significant loss of neutron-absorbing capacity of the plate-type carborundum material has been reported at Palisades.
The applicant should describe how the monitoring program described above is capable of detecting the aforementioned degradation mechanisms.
References Interim Staff Guidance LR-ISG-2009-01, Aging Management of Spent Fuel Pool Neutron-Absorbing Materials Other Than Boraflex, 2010.
Letter from Christopher J. Schwarz, Entergy Nuclear Operations, Inc., Palisades Nuclear Plant, to the U.S. Nuclear Regulatory Commission, Commitments to Address Degraded Spent Fuel Pool Storage Rack Neutron Absorber, August 27, 2008, (ADAMS Accession No. ML082410132).
Letter from Kevin L. Ostrowski, FirstEnergy Nuclear Operating Company, to the U.S. Nuclear Regulatory Commission, Supplemental Information for the Review of the Beaver Valley Power Station, Units 1 and 2, License Renewal Application (TAC Nos. MD6593 and MD6594) and License Renewal Application Amendment No. 34, January 19, 2009, (ADAMS Accession No. ML090220216).
NUREG-1801, Rev. 2 XI M40-2 December 201 0 OAG10001390_00676
Letter from Mark E. Warner, FPL Energy Seabrook Station, to the U.S. Nuclear Regulatory Commission, Seabrook Station Boral Spent Fuel Pool Test Coupons Report Pursuant to 10 CFR Part 21.21, October 6,2003 (ADAMS Accession No. ML032880525).
License Renewal Application Vogtle Electric Generating Plant Units 1 and 2, Southern Nuclear Operating Company, Inc., June 30,2007 (ADAMS Accession No. ML071840360).
NRC Information Notice 2009-26, Oegradation of Neutron-Absorbing Materials in the Spent Fuel Pool, U.S. Nuclear Regulatory Commission, October 28,2009.
December 201 0 XI M40-3 NUREG-1801, Rev. 2 OAG10001390_00677
XI.M41 BURIED AND UNDERGROUND PIPING AND TANKS Program Description This is a comprehensive program designed to manage the aging of the external surfaces of buried and underground piping and tanks and to augment other programs that manage the aging of internal surfaces of buried and underground piping and tanks. It addresses piping and tanks composed of any material, including metallic, polymeric, cementitious, and concrete materials. This program manages aging through preventive, mitigative, and inspection activities.
It manages all applicable aging effects such as loss of material, cracking, and changes in material properties.
Depending on the material, preventive and mitigative techniques may include the material itself, external coatings for external corrosion control, the application of cathodic protection, and the quality of backfill utilized. Also, depending on the material, inspection activities may include electrochemical verification of the effectiveness of cathodic protection, non-destructive evaluation of pipe or tank wall thicknesses, hydrotesting of the pipe, and visual inspections of the pipe or tank from the exterior as permitted by opportunistic or directed excavations.
Management of aging of the internal surfaces of buried and underground piping and tanks is accomplished through the use of other aging management programs (e.g., Open Cycle Cooling Water System (AMP XI.M20), Closed Treated Water System (AMP XI.M21A), Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components (AMP XI.M38), Fuel Oil Chemistry (AMP XI.M30), Fire Water System (AMP XI.M27), or Water Chemistry (AMP XI.M2)).
However, in some cases, this external surface program may be used in conjunction with the internal surface aging management programs to manage the aging of the internal surfaces of buried and underground piping and tanks. This program does not address selective leaching.
The Selective Leaching of Materials (AMP XI.M33) is applied in addition to this program for applicable materials and environments.
The terms "buried" and "underground" are fully defined in Chapter IX of the GALL Report.
Briefly, buried piping and tanks are in direct contact with soil or concrete (e.g., a wall penetration). Underground piping and tanks are below grade but are contained within a tunnel or vault such that they are in contact with air and are located where access for inspection is restricted.
Evaluation and Technical Basis
- 1. Scope of Program: This program is used to manage the effects of aging for buried and underground piping and tanks constructed of any material including metallic, polymeric, cementitious, and concrete materials. The program addresses aging effects such as loss of material, cracking, and changes in material properties. Typical systems in which buried and underground piping and tanks may be found include service water piping and components, condensate storage transfer lines, fuel oil and lubricating oil lines, fire protection piping and piping components (fire hydrants), and storage tanks. Loss of material due to corrosion of piping system bolting within the scope of this program is managed using this program. Other aging effects associated with piping system bolting are managed through the use of the Bolting Integrity Program (AM P XI. M 18).
December 201 0 XI M41-1 NUREG-1801, Rev. 2 OAGI0001390_00678
- 2. Preventive Actions: Preventive actions utilized by this program vary with the material of the tank or pipe and the environment (air, soil, or concrete) to which it is exposed. These actions are outlined below:
- a. Preventive Actions - Buried Piping and Tanks
- i. Preventive actions for buried piping and tanks are conducted in accordance with Table 2a and its accompanying footnotes.
Table 2a. Preventive Actions for Buried Piping and Tanks Material 1 Coating 2 Cathodic Protection 4 Backfill Quality Titanium Super Austenitic Stainless8 Stainless Steel X3 X5 ,7 Steel X X X5 Copper X X X5 Aluminum X X X5 Cementitious or Concrete X3 X5 ,7 Polymer X6
- 1. Materials classifications are meant to be broadly interpreted (e.g., all alloys of titanium that are commonly used for buried piping are to be included in the titanium category). Material categories are generally aligned with P numbers as found in the ASME Code,Section IX. Steel is defined in Chapter IX of this report. Polymer includes polymeric materials as well as composite materials such as fiberglass.
- 2. When provided, coatings are in accordance with Table 1 of NACE SP0169-2007 or Section 3.4 of NACE RP0285-2002.
- 3. Coatings are provided based on environmental conditions (e.g., stainless steel in chloride containing environments). If coatings are not provided, a justification is provided in the LRA.
- 4. Cathodic protection is in accordance with NACE SP0169-2007 or NACE RP0285-2002. The system should be operated so that the cathodic protection criteria and other considerations described in the standards are met at every location in the system. The duration of deviations from these criteria should not exceed 90 days. The system monitoring interval discussed in section 10.3 of NACE SP0169-2007 may not be extended beyond one year. The equipment used to implement cathodic protection need not be qualified in accordance with 10 CFR 50 Appendix B.
- 5. Backfill is consistent with SP0169-2007 section 5.2.3. The staff considers backfill that is located within 6 inches of the pipe that meets ASTM 0448-08 size number 67 to meet the objectives of SP0169-2007. For materials other than aluminum, the staff also considers the use of controlled low strength materials (flowable backfill) to meet the objectives of SP0169-2007. Backfill quality may be demonstrated by plant records or by examining the backfill while conducting the inspections conducted in program element 4 of this AMP. Backfill not meeting this standard, in either the initial or subsequent inspections, is acceptable if the inspections conducted in program element 4 of this AMP do not reveal evidence of mechanical damage to pipe coatings due to the backfill.
- 6. Backfill is consistent with SP0169-2007 section 5.2.3. The staff considers backfill that is located within 6 inches of the pipe that meets ASTM 0448-08 size number 10 to meet the objectives of SP0169-2007. The staff also considers the use of controlled low strength materials (flowable backfill) to meet the objectives of SP0169-2007. Backfill quality may be demonstrated by plant records or by examining the backfill while conducting the inspections conducted in program element 4 of this AMP. Backfill not meeting this standard, in either the initial or subsequent inspections, is acceptable if the inspections conducted in program element 4 of this AMP do not reveal evidence of mechanical damage to pipe coatings due to the backfill.
- 7. Backfill limits apply only if piping is coated.
- 8. Super austenitic stainless steel (e.g., AI6XN or 254 SMO).
ii. Fire mains are installed in accordance with National Fire Protection Association (NFPA) Standard 24. Preventive actions for fire mains beyond those in NFPA 24 need not be provided if the system undergoes either a periodic flow test in accordance with NFPA 25 or the activity of the jockey pump (or equivalent equipment or parameter) is monitored as described in program element 4 of this AMP.
NUREG-1801, Rev. 2 XI M41-2 December 201 0 OAGI0001390_00679
iii. When referenced, NACE SP0169-2007 is to be used in its entirety excepting Section 3, Determination of Need for External Corrosion Control. Use of Section 3 of the standard constitutes an exception to this AMP. Exceptions to the AMP related to the need for external corrosion control should include an analysis of issues such as those described in National Cooperative Highway Research Program (NCHRP)
Report 408, "Corrosion of Steel Piling in Non Marine Applications and American Association of State Highway and Transportation Officials (AASHTO) Standard R 27."
- b. Preventive Actions - Underground Piping and Tanks
- i. Preventive actions for underground piping and tanks are conducted in accordance with Table 2b and its accompanying footnotes.
Table 2b. Preventive Actions for Underground Piping and Tanks Material 1 Coating Provided 2 Titanium Super Austenitic Stainless3 Stainless Steel Steel X Copper X Aluminum Cementitious or Concrete Polymer
- 1. Materials classifications are meant to be broadly interpreted (e.g., all alloys of titanium that are commonly used for buried piping are to be included in the titanium category). Material categories are generally aligned with P numbers as found in the ASME Code,Section IX. Steel is defined in chapter IX of this report. Polymer includes polymeric materials as well as composite materials such as fiberglass.
- 2. When provided, coatings are in accordance with Table 1 of NACE SP0169-2007 or Section 3.4 of NACE RP0285-2002. A broader range of coatings may be used if justification is provided in the LRA.
- 3. Super austenitic stainless steel (e.g., AI6XN or 254 SMO).
- 3. Parameters Monitored/Inspected: The aging effects addressed by this AMP are changes in material properties of polymeric materials, loss of material due to all forms of corrosion and, potentially, cracking due to stress corrosion cracking. Changes in material properties are monitored by manual examinations. Loss of material is monitored by visual appearance of the exterior of the piping or tank and wall thickness of the piping or tank. Wall thickness is determined by a non-destructive examination technique such as ultrasonic testing (UT). Two additional parameters, the pipe-to-soil potential and the cathodic protection current, are monitored for steel, copper, and aluminum piping and tanks in contact with soil to determine the effectiveness of cathodic protection systems and, thereby, the effectiveness of corrosion mitigation.
- 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. These methods and frequencies are outlined below.
- a. Opportunistic Inspections December 201 0 XI M41-3 NUREG-1801, Rev. 2 OAG10001390_00680
- i. All buried and underground piping and tanks, regardless of their material of construction, are inspected by visual means whenever they become accessible for any reason. The information in paragraph f of this program element is applied in the event deterioration of piping or tanks is observed.
- b. Directed Inspections - Buried Pipe
- i. Directed inspections for buried piping are conducted in accordance with Table 4a and its accompanying footnotes. Modifications to this table may be appropriate if exceptions to program Element 2, Preventive Actions, are taken or in response to plant specific operating experience.
ii. Unless otherwise indicated, directed inspections as indicated in Table 4a will be conducted during each 10-year period beginning 10 years prior to the entry into the period of extended operation.
iii. Inspection locations are selected based on risk (based on susceptibility to degradation and consequences of failure). Characteristics such as coating type, coating condition, cathodic protection efficacy, backfill characteristics, soil resistivity, pipe contents, and pipe function are considered. Piping systems that are backfilled using controlled low strength material generally experience lower corrosion rates and may be more difficult to excavate than piping systems backfilled using compacted aggregate fill. As a result, piping systems that are backfilled using compacted aggregate should generally be given a higher inspection priority than comparable systems that are completely backfilled using controlled low strength material. For many piping systems, External Corrosion Direct Assessment (ECDA) as described in NACE Standard Practice SP0502-2010 has been demonstrated to be an effective method for use in the identification of pipe locations that merit further inspection.
iv. Visual inspections are supplemented with surface and/or volumetric non-destructive testing (NOT) if significant indications are observed.
- v. Opportunistic examinations of non leaking pipes may be credited toward these direct examinations if the location selection criteria in item iii, above, are met.
vi. At multi-unit sites, individual inspections of shared piping may be credited for only one unit.
vii. Visual inspections for polymeric materials are augmented with manual examinations to detect hardening, softening, or other changes in material properties.
viii. The use of guided wave ultrasonic or other advanced inspection techniques is encouraged for the purpose of determining those piping locations that should be inspected but may not be substituted for the inspections listed in the table.
ix. For the purpose of this program element, fire mains will be considered to be code class/safety-related piping and inspected as such unless they are subjected to either 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 or the activity of the jockey pump (or equivalent equipment or parameter) is monitored on an interval not to exceed 1 month. At a minimum, a flow test is conducted by the end of the next refueling outage or as directed by current NUREG-1801, Rev. 2 XI M41-4 December 201 0 OAGI0001390_00681
licensing basis, whichever is shorter, when unexplained changes in jockey pump activity (or equivalent equipment or parameter) are observed.
- x. Inspection as indicated in either (A) or (B) below may be performed in lieu of the inspections contained in Table 4a for either code class/safety significant or hazmat piping or both:
A. At least 25% of the code class/safety-related or hazmat piping or both constructed from the material under consideration is hydrostatically tested in accordance with 49 CFR 195 subpart E on an interval not to exceed 5 years.
B. At least 25% of the code class/safety-related or hazmat piping or both constructed from the material under consideration is internally inspected by a method capable of precisely determining pipe wall thickness. The inspection method must be capable of detecting both general and pitting corrosion and must be qualified by the applicant and approved by the staff. As of the effective date of this document, guided wave ultrasonic examinations do not meet this paragraph. Internal inspections are to be conducted at an interval not to exceed 5 years. Consideration should be given to NACE SP0169-2007 sections 6.1.2 and 6.3.3.
Table 4a. Inspections of Buried Pipe 1 Preventive Inspections 3 Material Actions 2 Code Class Safety-related 4 Hazmat5 Titanium Super Austenitic Stainless 7 Stainless Steel 16 16 A 16 16 HOPEB B 2 1%
6 A 1 16 Other Polymer B 2 1%
6 Cementitious or Concrete 1 16 C 16 16 0 1 2%
Steel E 4 10 5%10 F 8 10%
6 C 1 16 0 1 1%
Copper 110 E 2%10 F 2 5%
6 C 1 16 Aluminum 0 1 2%
E 1 5%
December 201 0 XI M41-S NUREG-1801, Rev. 2 OAG10001390_00682
Table 4a. Inspections of Buried Pipe Preventive Inspections 3 Material 1 Actions 2 Code Class Safety-related 4 Hazmat5 F 2 10%
- 1. Materials classifications are meant to be broadly interpreted (e.g., all alloys of titanium that are commonly used for buried piping are to be included in the titanium category). Material categories are generally aligned with P numbers as found in the ASME Code,Section IX. Steel is defined in chapter IX of this report. Polymer includes polymeric materials as well as composite materials such as fiberglass.
- 2. Preventive actions are categorized as follows:
A. Backfill is in accordance with Table 2a of this AMP.
B. Backfill is not in accordance with Table 2a of this AMP.
C. External corrosion control is provided in accordance with NACE SP0169-2007. Each cathodic protection system (a) was installed at least 5 years prior to the period of extended operation and was operational for 90% of the time during that 5-year period or (b) was operational for 90% of the time since the last inspection conducted under this program.
D. External corrosion control is provided in accordance with NACE SP0169-2007. Each cathodic protection system (a) was installed less than 5 years prior to the period of extended operation or was operational for less than 90% of the time during that 5-year period or (b) was operational for less than 90% of the time since the last inspection conducted under this program.
E. Coatings and backfill are in accordance with Table 2a of this AMP, but cathodic protection is not provided or is not consistent with criteria Cor D. This category is provided for use during the 10 years prior to the period of extended operation by applicants who are not able to install cathodic protection in accordance with program element 2 prior to entry into the period of extended operation. Following entry into the period of extended operation, consistency with program element 2 or an approved alternative is expected.
F. Preventive actions provided do not meet criteria C, 0, or E. This category is provided for use during the 10 years prior to the period of extended operation by applicants who are not able to install cathodic protection in accordance with program element 2 prior to entry into the period of extended operation. Following entry into the period of extended operation, consistency with program element 2 or an approved alternative is expected.
- 3. Inspections are listed as either a discrete number of visual examinations (excavations) or as a percentage of the linear length of piping under consideration. The following guidance related to the extent of inspections is provided:
A. Each inspection will examine either the entire length of a run of pipe or a minimum of 10 feet.
B. If the number of inspections times the minimum inspection length (10 feet) exceeds 10% of the length of the piping under consideration, only 10% need be inspected.
C. If the total length of in-scope pipe constructed of a given material times the percentage to be inspected is less than 10 feet, either 10 feet or the total length of pipe present, whichever is less, will be inspected.
- 4. Code Class and safety-related pipe that also meets the definition of hazmat pipe will be inspected as hazmat pipe.
- 5. Hazmat pipe is pipe that, during normal operation, contains material that, if released, could be detrimental to the environment. This includes chemical substances such as diesel fuel and radioisotopes. To be considered hazmat, the concentration of radioisotopes within the pipe during normal operation must exceed established standards such as the EPA drinking water standard. In the absence of such standards, the concentration of the radioisotope must exceed the greater of background or reliable level of detection. For tritium, the EPA drinking water standard (20,000 pC ilL) is used.
(This approach for defining hazmat is consistent with that used in classifying fluid services in ASME B31.3 appendix M.)
- 6. Only one inspection is conducted even if both Code Class/safety-related and hazmat pipe are present. No inspections are necessary if all the piping constructed from the material under consideration is fully backfilled using controlled low strength material.
- 7. Super austenitic stainless steel (e.g., AI6XN or 254 SMO).
- 8. High Density Polyethylene (HOPE) pipe includes only HOPE pipe approved for use by the NRC for buried applications.
- 9. Other polymer piping includes some HOPE pipe and all other polymeric materials including composite materials such as fiberglass.
- 10. Inspections may be reduced to one-half the level indicated in the table when performing the indicated inspections necessitates excavation of piping that has been fully backfilled using controlled low strength material. In conducting these inspections, the backfill may be excavated and the pipe examined, or the soil around the backfill may be excavated and the controlled low strength material backfill examined. The corrosion rate of piping that is fully encased within controlled low strength material backfill that shows no signs of degradation, particularly cracking, is expected to be minimal.
NUREG-1801, Rev. 2 XI M41-6 December 201 0 OAG10001390_00683
- c. Directed Inspections - Underground Pipe
- i. Directed inspections for underground piping are conducted in accordance with Table 4b and its accompanying footnotes.
ii. Unless otherwise indicated, directed inspections as indicated in Table 4b will be conducted during each 10-year period beginning 10 years prior to the entry into the period of extended operation.
iii. Inspection locations are selected based on risk (based on susceptibility to degradation and consequences of failure). Characteristics such as coating type, coating condition, exact external environment, pipe contents, pipe function, and flow characteristics within the pipe, are considered.
iv. Underground pipes are inspected visually to detect external corrosion and by a volumetric technique such as UT to detect internal corrosion.
- v. Opportunistic examinations may be credited toward these direct examinations if the location selection criteria in item iii, above, are met.
vi. At multi-unit sites, individual inspections of shared piping may be credited for only one unit.
vii. When access permits, visual inspections for polymeric materials are augmented with manual examinations to detect hardening, softening, or other changes in material properties.
viii. The use of guided wave ultrasonic or other advanced inspection techniques is encouraged for the purpose of determining those piping locations that should be inspected but may not be substituted for the inspections listed in the table.
ix. For the purpose of this program element, fire mains will be considered to be code class/safety-related piping and inspected as such unless they are subjected to either a flow test as described in section 7.3 of NFPA 25 at an frequency of at least one test in each 1-year period or the activity of the jockey pump (or equivalent equipment or parameter) is monitored on an interval not to exceed 1 month. At a minimum, a flow test is conducted by the end of the next refueling outage or as directed by current licensing basis, whichever is shorter, when unexplained changes in jockey pump activity (or equivalent equipment or parameter) are observed.
December 201 0 XI M41-7 NUREG-1801, Rev. 2 OAGI0001390_00684
Table 4b. Inspections of Underground Pipe Inspections 2 Material 1 Code Class Safety-related 3 Hazmat4 Titanium Super Austenitic Stainless6 Stainless Steel 15 15 HOPE 7 15 15 Other Polymer8 15 15 Cementitious or Concrete 15 15 Steel 2 2%
Copper 1 1%
Aluminum 1 1%
- 1. Materials classifications are meant to be broadly interpreted (e.g., all alloys of titanium that are commonly used for buried piping are to be included in the titanium category). Material categories are generally aligned with P numbers as found in the ASME Code,Section IX. Steel is as defined in chapter IX of this report. Polymer includes polymeric materials as well as composite materials such as fiberglass.
- 2. Inspections are listed as either a discrete number of visual examinations or as a percentage of the linear length of piping under consideration. The following guidance related to the extent of inspections is provided:
A. Each inspection will examine either the entire length of a run of pipe or a minimum of 10 feet.
B. If the number of inspections times the minimum inspection length (10 feet) exceeds 10% of the length of the piping under consideration, only 10% need be inspected.
C. If the total length of in scope pipe constructed of a given material times the percentage to be inspected is less than 10 feet, either 10 feet or the total length of pipe present, whichever is less, will be inspected.
- 3. Code Class and safety-related pipe that also meets the definition of hazmat pipe will be inspected as hazmat pipe.
- 4. Hazmat pipe is pipe that, during normal operation, contains material that, if released, could be detrimental to the environment. This includes chemical substances such as diesel fuel and radioisotopes. To be considered hazmat, concentration of radioisotope within the pipe during normal operation must exceed established standards such as the EPA drinking water standard. In the absence of such standards, the concentration of the radioisotope must exceed the greater of background or reliable level of detection. For tritium, the EPA drinking water standard (20,000 pC ilL) is used.
(This approach for defining hazmat is consistent with that used in classifying fluid services in ASME B31.3 appendix M.)
- 5. Only one inspection is conducted even if both Code Class/safety-related and hazmat pipe are present.
- 6. Super austenitic stainless steel (e.g., AI6XN or 254 SMO).
- 7. HOPE pipe includes only HOPE pipe approved for use by the NRC for buried applications.
- 8. Other polymer piping includes some HOPE pipe and all other polymeric materials including composite materials such as fiberglass.
- x. Inspection as indicated in (A), and (8) below may be performed in lieu of the inspections contained in Table 4a for either code class/safety significant or hazmat piping or both:
A. At least 25% of the code class/safety-related or hazmat piping or both constructed from the material under consideration is hydrostatically tested in accordance with 49 CFR 195 subpart E on an interval not to exceed 5 years.
- 8. At least 25% of the code class/safety-related or hazmat piping or both constructed from the material under consideration is internally inspected by a method capable of precisely determining pipe wall thickness. The inspection method must be capable of detecting both general and pitting corrosion and must be qualified by the applicant and approved by the staff. As of the effective date of this document, guided wave ultrasonic examinations do not meet this paragraph. Internal inspections are to be conducted at an interval NUREG-1801, Rev. 2 XI M41-8 December 201 0 OAGI0001390_00685
not to exceed 5 years. Consideration should be given to SP0169-2007 sections 6.1.2 and 6.3.3.
- d. Directed Inspections - Buried Tanks
- i. Directed inspections for buried tanks are conducted in accordance with Table 4c and its accompanying footnotes. Modifications to this table may be appropriate if exceptions to program Element 2, preventive actions, are taken or in response to plant specific operating experience.
ii. Directed inspections as indicated in Table 4c will be conducted during each 10-year period beginning 10 years prior to the entry into the period of extended operation.
iii. Each buried tank is examined if it is Code Class/safety-related or contains hazardous materials as defined in footnote 5 to Table 4a and it is constructed from a material for which an examination is indicated in Table 4c.
iv. Examinations may be conducted from the external surface of the tank using visual techniques or from the internal surface of the tank using volumetric techniques. If the tank is inspected from the external surface, a minimum 25% coverage is required.
This area must include at least some of both the top and bottom of the tank. If the tank is inspected internally by UT, at least one measurement is required per square foot of tank surface. UT measurements are distributed uniformly over the surface of the tank. If the tank is inspected internally by another volumetric technique, at least 90% of the surface of the tank must be inspected. Double wall tanks may be examined by monitoring the annular space for leakage.
- v. Visual inspections for polymeric materials are augmented with manual examinations to detect hardening, softening, or other changes in material properties.
vi. Opportunistic examinations may be credited toward these direct examinations.
Table 4c. Inspections of Buried Tanks Preventive Material 1 Inspections Actions 2 Titanium Super Austenitic Stainless3 Stainless Steel A
HDPE 4 B X A
Other Polymer B X Cementitious or Concrete X C
Steel D E X December 201 0 XI M41-9 NUREG-1801, Rev. 2 OAG10001390_00686
Table 4c. Inspections of Buried Tanks Preventive Material 1 Inspections Actions 2 C
Copper D E x C
Aluminum D E x
- 1. Materials classifications are meant to be broadly interpreted (e.g., all alloys of titanium that are commonly used for buried piping are to be included in the titanium category). Material categories are generally aligned with P numbers as found in the ASME Code,Section IX. Steel is defined in chapter IX of this report. Polymer includes polymeric materials as well as composite materials such as fiberglass.
- 2. Preventive actions are categorized as follows:
A. Backfill is in accordance with Table 2a of this AMP.
B. Backfill is not in accordance with Table 2a of this AMP.
C. External corrosion control is provided in accordance with NACE RP0285-2002. Each cathodic protection system (a) was installed at least 5 years prior to the period of extended operation and was operational for 90% of the time during that 5-year period or (b) was operational for 90% of the time since the last inspection conducted under this program.
O. External corrosion control is provided in accordance with NACE RP0285-2002. Each cathodic protection system (a) was installed less than 5 years prior to the period of extended operation or was operational for less than 90% of the time during that 5-year period or (b) was operational for less than 90% of the time since the last inspection conducted under this program.
E. Cathodic protection is not provided. This category is provided for use during the 10 years prior to the period of extended operation by applicants who are not able to install cathodic protection in accordance with program element 2 prior to entry into the period of extended operation. Following entry into the period of extended operation, consistency with program element 2 or an approved alternative is expected.
- 3. Super austenitic stainless steel (e.g., AI6XN or 254 SMO).
- 4. HOPE includes only HOPE material approved for use by the NRC for buried applications.
- 5. Other polymer includes some HOPE material and all other polymeric materials including composite materials such as fiberglass.
- e. Directed Inspections - Underground Tanks
- i. Directed inspections for underground tanks are conducted in accordance with Table 4d and its accompanying footnotes.
ii. Directed inspections as indicated in Table 4d will be conducted during each 10-year period beginning 10 years prior to the entry into the period of extended operation.
Table 4d. Inspections of Underground Tanks Material 1 Inspections Titanium Super Austenitic Stainless2 Stainless Steel HDPE 3 Other Polymer4 Cementitious or concrete Steel X NUREG-1801, Rev. 2 XI M41-10 December 201 0 OAG10001390_00687
Table 4d. Inspections of Underground Tanks Material 1 Inspections Copper Aluminum
- 1. Materials classifications are meant to be broadly interpreted (e.g., all alloys of titanium that are commonly used for buried piping are to be included in the titanium category). Material categories are generally aligned with P numbers as found in the ASME Code,Section IX. Steel is as defined in chapter IX of this report. Polymer includes polymeric materials as well as composite materials such as fiberglass.
- 2. Super austenitic stainless steel (e.g., AI6XN or 254 SMO).
- 3. HOPE includes only HOPE material approved for use by the NRC for buried applications.
- 4. Other polymer includes some HOPE material and all other polymeric materials including composite materials such as fiberglass.
iii. Each underground tank that is Code Class/safety-related or contains hazardous materials as defined in footnote 5 to Table 4a and is constructed from a material for which an examination is indicated in Table 4d is examined.
iv. Examinations may be conducted from the external surface of the tank using visual techniques or from the internal surface of the tank using volumetric techniques. If the tank is inspected from the external surface, a minimum 25% coverage is required.
This area must include at least some of both the top and bottom of the tank. If the tank is inspected internally by UT, at least one measurement is required per square foot of tank surface. If the tank is inspected internally by another volumetric technique, at least 90% of the surface of the tank must be inspected. Double wall tanks may be examined by monitoring the annular space for leakage.
- v. Tanks that cannot be examined using volumetric examination techniques are examined visually from the outside.
vi. When access permits, visual inspections for polymeric materials are augmented with manual examinations to detect hardening, softening, or other changes in material properties.
vii. Opportunistic examinations may be credited toward these direct examinations.
- f. Adverse indications
- i. Adverse indications observed during monitoring of cathodic protection systems or during inspections are entered into the plant corrective action program. Adverse indications that are the result of inspections will result in an expansion of sample size as described in item iv, below. Adverse indications that are the result of monitoring of a cathodic protection system may warrant increased monitoring of the cathodic protection system and/or additional inspections. Examples of adverse indications resulting from inspections include leaks, material thickness less than minimum, the presence of coarse backfill with accompanying coating degradation within 6 inches of a coated pipe or tank (see Table 2a Footnotes 5 and 6), and general or local degradation of coatings so as to expose the base material.
ii Adverse indications that fail to meet the acceptance criteria described in program element 6 of this AMP will result in the repair or replacement of the affected component.
December 201 0 XI M41-11 NUREG-1801, Rev. 2 OAG10001390_00688
iii. An analysis may be conducted to determine the potential extent of the degradation observed. Expansion of sample size may be limited by the extent of piping or tanks subject to the observed degradation mechanism.
iv. If adverse indications are detected, inspection sample sizes within the affected piping categories are doubled. If adverse indications are found in the expanded sample, the inspection sample size is again doubled. This doubling of the inspection sample size continues as necessary.
- 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 similar parameter), 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.
- 6. Acceptance Criteria: The principal acceptance criteria associated with the inspections contained with this AMP follow:
- a. Criteria for soil-to-pipe potential are listed in NACE RP0285-2002 and SP0169-2007.
- b. For coated piping or tanks, there should be either no evidence of coating degradation or the type and extent of coating degradation should be insignificant as evaluated by an individual possessing a NACE operator qualification or otherwise meeting the qualifications to evaluate coatings as contained in 49 CFR 192 and 195.
- c. 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.
- d. Cracking or blistering of nonmetallic piping is evaluated.
- e. Cementitious or concrete piping may exhibit minor cracking and spalling provided there is no evidence of leakage or exposed rebar or reinforcing "hoop" bands.
- f. Backfill is in accordance with specifications described in program element 2 of this AMP.
- g. Flow test results for fire mains are in accordance with NFPA 25 section 7.3.
- h. For hydrostatic tests, the condition "without leakage" as required by 49 CFR 195.302 may be met by demonstrating that the test pressure, as adjusted for temperature, does not vary during the test.
- i. Changes in jockey pump activity (or similar parameter) that cannot be attributed to causes other than leakage from buried piping are not occurring.
- 7. Corrective Actions: The site corrective actions program, quality assurance (QA) procedures, site review and approval process, and administrative controls are implemented in accordance with the requirements of 10 CFR Part 50, Appendix B. The staff finds the NUREG-1801, Rev. 2 XI M41-12 December 201 0 OAG10001390_00689
requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions, confirmation process, and administrative controls.
- 8. Confirmation Process: The confirmation process ensures that preventive actions are adequate to manage the aging effects and that appropriate corrective actions have been completed and are effective. The confirmation process for this program is implemented through the site's QA program in accordance with the requirements of 10 CFR Part 50, Appendix B.
- 9. Administrative Controls: The administrative controls for this program provide for a formal review and approval of corrective actions. The administrative controls for this program are implemented through the site's QA program in accordance with the requirements of 10 CFR Part 50, Appendix B.
- 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 applicants to evaluate both plant-specific and nuclear industry operating experience and to modify its aging management program accordingly. The following industry experience may be of significance to an applicant's program:
- a. In February 2005, a leak was detected in a 4-inch condensate storage supply line. The cause of the leak was microbiologically influenced corrosion or under deposit corrosion.
The leak was repaired in accordance with the American Society of Mechanical Engineers (ASME)Section XI, "Repair/Replacement Plan."
- b. In September 2005, a service water leak was discovered in a buried service water header. The header had been in service for 38 years. The cause of the leak was either failure of the external coating or damage caused by improper backfill. The service water header was relocated above ground.
- c. In October 2007, degradation of essential service water piping was reported. The riser pipe leak was caused by a loss of pipe wall thickness due to external corrosion induced by the wet environment surrounding the unprotected carbon steel pipe. The corrosion processes that caused this leak affected all eight similar locations on the essential service water riser pipes within vault enclosures and had occurred over many years.
- d. In February 2009, a leak was discovered on the return line to the condensate storage tank. The cause of the leak was coating degradation probably due to the installation specification not containing restrictions on the type of backfill allowing rocks in the backfill. The leaking piping was also located close to water table.
- e. In April 2009, a leak was discovered in an aluminum pipe where it went through a concrete wall. The piping was for 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.
December 201 0 XI M41-13 NUREG-1801, Rev. 2 OAG10001390_00690
- f. 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.
References 10 CFR Part 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
49 CFR 195 subpart E, Transportation of Hazardous Liquids by Pipeline, Pressure Testing.
Office of the Federal Register, National Archives and Records Administration, 2009.
AASHTO R 27, Standard Practice for Assessment of Corrosion of Steel Piling for Non Marine Applications, American Association of State Highway and Transportation Officials, Washington DC, 2006.
ASME Boiler and Pressure Vessel Code,Section IX, Welding and Brazing, American Society of Mechanical Engineers, 2004.
ASME Standard B31.3, Process Piping, Appendix M, American Society of Mechanical Engineers, 2002.
ASTM Standard D 448-08, Standard Classification for Sizes of Aggregate for Road and Bridge Construction, 2008.
J. A. Beavers and C. L. Durr, Corrosion of Steel Piping in Non Marine Applications, NCHRP Report 408, Transportation Research Board, National Research Council, Washington DC, 1998.
NACE Recommended Practice RP0285-2002, Standard Recommended Practice Corrosion Control of Underground Storage Tank Systems by Cathodic Protection, revised April 2002.
NACE Recommended Practice RP0502-2010, Pipeline External Corrosion Direct Assessment Methodology, 2010.
NACE Standard Practice SP0169-2007, Control of External Corrosion on Underground or Submerged Metallic Piping Systems, 2007.
NFPA Standard 24, Standard for the Installation of Private Fire Service Mains and Their Appurtenances, 2010 edition.
NFPA Standard 25, Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems, 2008 edition.
NUREG-1801, Rev. 2 XI M41-14 December 201 0 OAG10001390_00691
XI.S1 ASME SECTION XI, SUBSECTION IWE Program Description 10 CFR SO.SSa imposes the inservice inspection (lSI) requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code,Section XI, Subsection IWE, for steel containments (Class MC) and steel liners for concrete containments (Class CC). The full scope of IWE includes steel containment shells and their integral attachments, steel liners for concrete containments and their integral attachments, containment hatches and airlocks and moisture barriers, and pressure-retaining bolting. This evaluation covers the 2004 edition,20 as approved in 10 CFR SO.SSa. ASME Code,Section XI, Subsection IWE, and the additional requirements specified in 10 CFR SO.SSa(b)(2) constitute an existing mandated program applicable to managing aging of steel containments, steel liners of concrete containments, and other containment components for license renewal.
The primary lSI method specified in IWE is visual examination (general visual, VT-3, VT-1).
Limited volumetric examination (ultrasonic thickness measurement) and surface examination (e.g., liquid penetrant) may also be necessary in some instances to detect aging effects. IWE specifies acceptance criteria, corrective actions, and expansion of the inspection scope when degradation exceeding the acceptance criteria is found.
Subsection IWE requires examination of coatings that are intended to prevent corrosion. AMP XI.S8 is a protective coating monitoring and maintenance program that is recommended to ensure Emergency Core Cooling System (ECCS) operability, whether or not the AMP XI.S8 is credited in AMP XI.S1.
The program attributes are augmented to incorporate aging management activities, recommended in the Final Interim Staff Guidance LR-ISG-2006-01, needed to address the potential loss of material due to corrosion in the inaccessible areas of the boiling water reactor (BWR) Mark I steel containment.
The attributes also are augmented to require surface examination for detection of cracking described in NRC Information Notice (IN) 92-20 and to address recommendations delineated in NUREG-1339 and industry recommendations delineated in the Electric Power Research Institute (EPRI) NP-S769, NP-S067, and TR-104213 for structural bolting. The program is also augmented to require surface examination of dissimilar metal welds of vent line bellows in accordance with examination Category E-F, as specified in the 1992 Edition of the ASME Code,Section XI, Subsection IWE. If surface examination is not possible, appropriate 10 CFR Part SO Appendix J test may be conducted for pressure boundary components.
Evaluation and Technical Basis
- 1. Scope of Program: The scope of this program addresses the components of steel containments and steel liners of concrete containments specified in Subsection IWE-1000 as augmented by LR-ISG-2006-01. The components within the scope of Subsection IWE are Class MC pressure-retaining components (steel containments) and their integral attachments, metallic shell and penetration liners of Class CC containments and their integral attachments, containment moisture barriers, containment pressure-retaining bolting, and metal containment surface areas, including welds and base metal. The concrete 20 Refer to the GALL Report, Chapter I, for applicability of other editions of the ASME Code,Section XI.
December 201 0 XI S1-1 NUREG-1801, Rev. 2 OAG10001390_00692
portions of containments are inspected in accordance with Subsection IWL. Subsection IWE requires examination of coatings that are intended to prevent corrosion. XI.S8 is a protective coating monitoring and maintenance program that is recommended to ensure ECCS operability, whether or not the AMP XI.S8 is credited in AMP XI.S1.
Subsection IWE exempts the following from examination:
(a) Components that are outside the boundaries of the containment, as defined in the plant-specific design specification; (b) Embedded or inaccessible portions of containment components that met the requirements of the original construction code of record; (c) Components that become embedded or inaccessible as a result of containment structure (i.e., steel containments [Class MC] and steel liners of concrete containments [Class CC]) repair or replacement, provided the requirements of IWE-1232 and IWE-5220 are met; and (d) Piping, pumps, and valves that are part of the containment system or that penetrate or are attached to the containment vessel (governed by IWB or IWC).
10 CFR 50.55a(b)(2)(ix) specifies additional requirements for inaccessible areas. It states that the licensee is to evaluate the acceptability of inaccessible areas when conditions exist in accessible areas that could indicate the presence of or result in degradation to such inaccessible areas. Examination requirements for containment supports are not within the scope of Subsection IWE.
- 2. Preventive Action: The ASME Code Section XI, Subsection IWE, is a condition monitoring program. The program is augmented to include preventive actions that ensure that moisture levels associated with an accelerated corrosion rate do not exist in the exterior portion of the BWR Mark I steel containment drywell shell. The actions consist of ensuring that the sand pocket area drains and/or the refueling seal drains are clear. The program is also augmented to require that the selection of bolting material installation torque or tension and the use of lubricants and sealants are in accordance with the guidelines of EPRI NP-5769, EPRI TR-104213, and the additional recommendations of NUREG-1339 to prevent or mitigate degradation and failure of structural bolting. If the structural bolting consists of ASTM A325, ASTM F1852, and/or ASTM A490 bolts, the preventive actions for storage, lubricants, and stress corrosion cracking potential discussed in Section 2 of RCSC (Research Council for Structural Connections) publication "Specification for Structural Joints Using ASTM A325 or A490 Bolts," need to be considered.
- 3. Parameters Monitored or Inspected: Table IWE-2500-1 references the applicable sections in IWE-2300 and IWE-3500 that identify the parameters examined or monitored. Non-coated surfaces are examined for evidence of cracking, discoloration, wear, pitting, excessive corrosion, arc strikes, gouges, surface discontinuities, dents, and other signs of surface irregularities. Painted or coated surfaces are examined for evidence of flaking, blistering, peeling, discoloration, and other signs of distress. Stainless steel penetration sleeves, dissimilar metal welds, bellows, and steel components that are subject to cyclic loading but have no current licensing basis fatigue analysis are monitored for cracking. The moisture barriers are examined for wear, damage, erosion, tear, surface cracks, or other defects that permit intrusion of moisture in the inaccessible areas of the pressure retaining surfaces of NUREG-1801, Rev. 2 XI S1-2 December 201 0 OAG10001390_00693
the metal containment shell or liner. Pressure-retaining bolting is examined for loosening and material conditions that cause the bolted connection to affect either containment leak-tightness or structural integrity.
As recommended in LR-ISG-2006-01, license renewal applicants with BWR Mark I steel containments should monitor the sand pocket area drains and/or the refueling seal drains for water leakage. The licensees should ensure the drains are clear to prevent moisture levels associated with accelerated corrosion rates in the exterior portion of the drywell shell.
- 4. Detection of Aging Effects: The examination methods, frequency, and scope of examination specified in 10 CFR 50.55a and Subsection IWE ensure that aging effects are detected before they compromise the design-basis requirements. IWE-2500-1 and the requirements of 10 CFR 50.55a provide information regarding the examination categories, parts examined, and examination methods to be used to detect aging.
As indicated in IWE-2400, inservice examinations are performed in accordance with one of two inspection programs, A or B, on a specified schedule. Under Inspection Program A, there are four inspection intervals (at 3, 10,23, and 40 years) for which 100% of the required examinations must be completed. Within each interval, there are various inspection periods for which a certain percentage of the examinations are to be performed to reach 100% at the end of that interval.
After 40 years of operation, any future examinations are performed in accordance with Inspection Program B. Under Inspection Program B, starting with the time the plant is placed into service, there is an initial inspection interval of 10 years and successive inspection intervals of 10 years each, during which 100% of the required examinations are to be completed. An expedited examination of containment is required by 10 CFR 50.55a, in which an inservice (baseline) examination specified for the first period of the first inspection interval for containment was to be performed by September 9, 2001. Thereafter, subsequent examinations are performed every 10 years from the baseline examination. Regarding the extent of examination, all accessible surfaces receive a visual examination as specified in Table IWE-2500-1 and the requirements of 10 CFR 50.55a. The acceptability of inaccessible areas of the BWR Mark I steel containment drywell is evaluated when conditions exist in the adjacent accessible areas that could indicate the presence of moisture or could result in degradation to such inaccessible areas. IWE-1240 requires augmented examinations (Examination Category E-C) of containment surface areas subject to degradation. A VT-1 visual examination is performed for areas accessible from both sides, and volumetric (ultrasonic thickness measurement) examination is performed for areas accessible from only one side.
The requirements of ASME Section XI, Subsection IWE and 10 CFR 50.55a are augmented to require surface examination, in addition to visual examination, to detect cracking in stainless steel penetration sleeves, dissimilar metal welds, bellows, and steel components that are subject to cyclic loading but have no current licensing basis fatigue analysis. Where feasible, Appendix J tests (AMP XI.S4) may be performed in lieu of the surface examination.
- 5. Monitoring and Trending: With the exception of inaccessible areas, all surfaces are monitored by virtue of the examination requirements on a scheduled basis.
IWE-2420 specifies that:
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(a) The sequence of component examinations established during the first inspection interval shall be repeated.
(b) When examination results require evaluation of flaws or areas of degradation in accordance with IWE-3000, and the component is acceptable for continued service, the areas containing such flaws or areas of degradation shall be reexamined during the next inspection period listed in the schedule of the inspection program of IWE-2411 or IWE-2412, in accordance with Table IWE-2500-1, Examination Category E-C.
(c) When the reexaminations required by IWE-2420(b) reveal that the flaws or areas of degradation remain essentially unchanged for the next inspection period, these areas no longer require augmented examination in accordance with Table IWE-2500-1 and the regular inspection schedule is continued.
Applicants for license renewal for plants with BWR Mark I containment should augment IWE monitoring and trending requirements to address inaccessible areas of the drywell. The applicant should consider the following recommended actions based on plant-specific operating experience.
(a) Develop a corrosion rate that can be inferred from past ultrasonic testing (UT) examinations or establish a corrosion rate using representative samples in similar operating conditions, materials, and environments. If degradation has occurred, provide a technical basis using the developed or established corrosion rate to demonstrate that the drywell shell will have sufficient wall thickness to perform its intended function through the period of extended operation.
(b) Demonstrate that UT measurements performed in response to U.S. Nuclear Regulatory Commission (NRC) Generic Letter (GL) 87-05 did not show degradation inconsistent with the developed or established corrosion rate.
- 6. Acceptance Criteria: IWE-3000 provides acceptance standards for components of steel containments and liners of concrete containments. IWE-3410 refers to criteria to evaluate the acceptability of the containment components for service following the preservice examination and each inservice examination. Most of the acceptance standards rely on visual examinations. Areas that are suspect require an engineering evaluation or require correction by repair or replacement. For some examinations, such as augmented examinations, numerical values are specified for the acceptance standards. For the containment steel shell or liner, material loss locally exceeding 10% of the nominal containment wall thickness or material loss that is projected to locally exceed 10% of the nominal containment wall thickness before the next examination are documented. Such areas are corrected by repair or replacement in accordance with IWE-3122 or accepted by engineering evaluation. Cracking of stainless steel penetration sleeves, dissimilar metal welds, bellows, and steel components that are subject to cyclic loading but have no current licensing basis fatigue analysis is corrected by repair or replacement or accepted by engineering evaluation.
- 7. Corrective Actions: Subsection IWE states that components whose examination results indicate flaws or areas of degradation that do not meet the acceptance standards listed in IWE-3500 are acceptable if an engineering evaluation indicates that the flaw or area of degradation is nonstructural in nature or has no effect on the structural integrity of the NUREG-1801, Rev. 2 XI S1-4 December 201 0 OAG10001390_00695
containment. Components that do not meet the acceptance standards are subject to additional examination requirements, and the components are repaired or replaced to the extent necessary to meet the acceptance standards of IWE-3000. For repair of components within the scope of Subsection IWE, IWE-3124 states that repairs and reexaminations are to comply with IWA-4000. IWA-4000 provides repair specifications for pressure retaining components, including metal containments and metallic liners of concrete containments. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions.
If moisture has been detected or suspected in the inaccessible area on the exterior of the Mark I containment drywell shell or the source of moisture cannot be determined subsequent to root cause analysis, then:
(a) Include in the scope of license renewal any components that are identified as a source of moisture, if applicable, such as the refueling seal or cracks in the stainless liners of the refueling cavity pools walls, and perform aging management review.
(b) Identify surfaces requiring examination by implementing augmented inspections for the period of extended operation in accordance with Subsection IWE-1240, as identified in Table IWE-2500-1, Examination Category E-C.
(c) Use examination methods that are in accordance with Subsection IWE-2500.
(d) Demonstrate, through use of augmented inspections performed in accordance with Subsection IWE, that corrosion is not occurring or that corrosion is progressing so slowly that the age-related degradation will not jeopardize the intended function of the drywell shell through the period of extended operation.
- 8. Confirmation Process: When areas of degradation are identified, an evaluation is performed to determine whether repair or replacement is necessary. If the evaluation determines that repair or replacement is necessary, Subsection IWE specifies confirmation that appropriate corrective actions have been completed and are effective. Subsection IWE states that repairs and reexaminations are to comply with the requirements of IWA-4000.
Reexaminations are conducted in accordance with the requirements of IWA-2200, and the recorded results are to demonstrate that the repair meets the acceptance standards set forth in IWE-3500. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the confirmation process.
- 9. Administrative Controls: IWA-6000 provides specifications for the preparation, submittal, and retention of records and reports. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address administrative controls.
- 10. Operating Experience: ASME Section XI, Subsection IWE, was incorporated into 10 CFR 50.55a in 1996. Prior to this time, operating experience pertaining to degradation of steel components of containment was gained through the inspections required by 10 CFR Part 50, Appendix J and ad hoc inspections conducted by licensees and the NRC. NRC Information Notice (IN) 86-99, IN 88-82, IN 89-79, IN 2004-09, and NUREG-1522 described occurrences of corrosion in steel containment shells. NRC GL 87-05 addressed the potential for corrosion of BWR Mark I steel drywells in the "sand pocket region."
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NRC IN 97-10 identified specific locations where concrete containments are susceptible to liner plate corrosion; IN 92-20 described an instance of containment bellows cracking, resulting in loss of leak tightness. More recently, IN 2006-01 described a through-wall cracking and its probable cause in the torus of a BWR Mark I containment. The cracking was identified by the licensee in the heat-affected zone at the high pressure cooling injection (HPCI) turbine exhaust pipe torus penetration.
The licensee concluded that the cracking was most likely initiated by cyclic loading due to condensation oscillation during HPCI operation. These condensation oscillations induced on the torus shell may have been excessive due to a lack of an HPCI turbine exhaust pipe sparger that many licensees have installed. Other operating experience indicates that foreign objects embedded in concrete have caused through-wall corrosion of the liner plate at a few plants with reinforced concrete containments.
The program is to consider the liner plate and containment shell corrosion and cracking concerns described in these generic communications. Implementation of the lSI requirements of Subsection IWE, in accordance with 10 CFR 50.55a, augmented to consider operating experience, and as recommended in LR-ISG-2006-01, is a necessary element of aging management for steel components of steel and concrete containments through the period of extended operation.
Degradation of threaded bolting and fasteners in closures for the reactor coolant pressure boundary has occurred from boric acid corrosion, stress corrosion cracking (SCC), and fatigue loading (NRC IE Bulletin 82-02, NRC GL 91-17). SCC has occurred in high strength bolts used for nuclear steam supply system component supports (EPRI NP-5769). The augmented ASME Section XI, Subsection IWE, incorporating recommendations documented in EPRI NP-5769 and TR-104213, is necessary to ensure containment bolting integrity.
References 10 CFR Part 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
10 CFR Part 50, Appendix J, Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors, Office of the Federal Register, National Archives and Records Administration, 2009.
10 CFR 50.55a, Codes and Standards, Office of the Federal Register, National Archives and Records Administration, 2009.
ASME Section XI, Rules for In service Inspection of Nuclear Power Plant Components, Subsection IWA, General Requirements, The ASME Boiler and Pressure Vessel Code, 2004 edition as incorporated by reference in 10 CFR 50.55a, The American Society of Mechanical Engineers, New York, NY.
ASME Section XI, Rules for In service Inspection of Nuclear Power Plant Components, Subsection IWB, Requirements for Class 1 Components of Light-Water Cooled Power Plants, The ASME Boiler and Pressure Vessel Code, 2004 edition as incorporated by reference in 10 CFR 50.55a, The American Society of Mechanical Engineers, New York, NY.
NUREG-1801, Rev. 2 XI S1-6 December 201 0 OAG10001390_00697
ASME Section XI, Rules for In service Inspection of Nuclear Power Plant Components, Subsection IWC, Requirements for Class 2 Components of Light-Water Cooled Power Plants, The ASME Boiler and Pressure Vessel Code, 2004 edition as approved in 10 CFR 50.55a, The American Society of Mechanical Engineers, New York, NY.
ASME Section XI, Rules for In service Inspection of Nuclear Power Plant Components, Subsection IWE, Requirements for Class MC and Metallic Liners of Class CC Components of Light-Water Cooled Power Plants, The ASME Boiler and Pressure Vessel Code, 2004 edition as incorporated by reference in 10 CFR 50.55a, The American Society of Mechanical Engineers, New York, NY.
ASME Section XI, Rules for In service Inspection of Nuclear Power Plant Components, Subsection IWL, Requirements for Class CC Concrete Components of Light-Water Cooled Power Plants, The ASME Boiler and Pressure Vessel Code, 2004 edition as incorporated by reference in 10 CFR 50.55a, The American Society of Mechanical Engineers, New York, NY.
EPRI NP-5769, Degradation and Failure of Bolting in Nuclear Power Plants, Volumes 1 and 2, Electric Power Research Institute, April 1988.
EPRI NP-5067, Good Bolting Practices, A Reference Manual for Nuclear Power Plant Maintenance Personnel, Volume 1: Large Bolt Manual, 1987; Volume 2: Small Bolts and Threaded Fasteners, Electric Power Research Institute, 1990.
EPRI TR-104213, Bolted Joint Maintenance & Application Guide, Electric Power Research Institute, December 1995.
RCSC (Research Council on Structural Connections): Specification for Structural Joints Using ASTM A325 or A490 Bolts, 2004.
NRC IE Bulletin No. 82-02, Degradation of Threaded Fasteners in the Reactor Coolant Pressure Boundary of PWR Plants, U.S. Nuclear Regulatory Commission, June 2, 1982.
NRC Generic Letter 87-05, Request for Additional Information Assessment of Licensee Measures to Mitigate and/or Identify Potential Degradation of Mark I Drywells, U.S. Nuclear Regulatory Commission, March 12, 1987.
NRC Generic Letter 91-17, Generic Safety Issue 79, Bolting Degradation or Failure in Nuclear Power Plants, U.S. Nuclear Regulatory Commission, October 17, 1991.
NRC Information Notice 86-99, Degradation of Steel Containments, U.S. Nuclear Regulatory Commission, December 8, 1986 and Supplement 1, February 14, 1991.
NRC Information Notice 88-82, Torus Shells with Corrosion and Degraded Coatings in BWR Containments, U.S. Nuclear Regulatory Commission, October 14, 1988 and Supplement 1, May 2,1989.
NRC Information Notice 89-79, Degraded Coatings and Corrosion of Steel Containment Vessels, U.S. Nuclear Regulatory Commission, December 1, 1989 and Supplement 1, June 29, 1989.
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NRC Information Notice 92-20, Inadequate Local Leak Rate Testing, U.S. Nuclear Regulatory Commission, March 3, 1992.
NRC Information Notice 97-10, Liner Plate Corrosion in Concrete Containment, U.S. Nuclear Regulatory Commission, March 13, 1997.
NRC Information Notice 2004-09, Corrosion of Steel Containment and Containment Liner, U.S.
Nuclear Regulatory Commission, April 27, 2004.
NRC Information Notice 2006-01, Torus Cracking in a BWR Mark I Containment, U.S. Nuclear Regulatory Commission, January 12, 2006.
NRC Morning Report, Failure of Safety/Relief Valve Tee-Quencher Support Bolts, March 14, 2005. (ADAMS Accession Number ML050730347)
N U REG-1339, Resolution of Generic Safety Issue 29: Bolting Oegradation or Failure in Nuclear Power Plants, U.S. Nuclear Regulatory Commission, June 1990.
NUREG-1522, Assessment of Inservice Conditions of Safety-Related Nuclear Plant Structures, June 1995.
Staff Position and Rationale for the Final License Renewal Interim Staff Guidance LR-ISG-2006-01, Plant-Specific Aging Management Program for Inaccessible Areas of Boiling Water Reactor (BWR) Mark I Steel Containments Orywell Shell, Nuclear Regulatory Commission, November 16, 2006.
NUREG-1801, Rev. 2 XI S1-8 December 201 0 OAG10001390_00699
XI.S2 ASME SECTION XI, SUBSECTION IWL Program Description 10 CFR 50.55a imposes the examination requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code,Section XI, Subsection IWL, for reinforced and prestressed concrete containments (Class CC). The scope of IWL includes reinforced concrete and unbonded post-tensioning systems. This evaluation covers the 2004 21 edition of the ASME Code,Section XI, as approved in 10 CFR 50.55a. ASME Code,Section XI, Subsection IWL and the additional requirements specified in 10 CFR 50.55a(b)(2) constitute an existing mandated program applicable to managing aging of containment reinforced concrete and unbonded post-tensioning systems for license renewal.
The primary inspection method specified in IWL-2500 is visual examination, supplemented by testing. For prestressed containments, tendon wires are tested for yield strength, ultimate tensile strength, and elongation. Tendon corrosion protection medium is analyzed for alkalinity, water content, and soluble ion concentrations. The quantity of free water contained in the anchorage end cap and any free water that drains from tendons during the examination is documented. Samples of free water are analyzed for pH. Prestressing forces are measured in selected sample tendons. IWL specifies acceptance criteria, corrective actions, and expansion of the inspection scope when degradation exceeding the acceptance criteria is found.
The 2004 edition of the Code specifies augmented examination requirements following post-tensioning system repair/replacement activities. The post-tensioning system repair/replacement activities are to be in accordance with the requirements of the 2004 edition of the Code.
Evaluation and Technical Basis
- 1. Scope of Program: Subsection IWL-1000 specifies the components of concrete containments within its scope. The components within the scope of Subsection IWL are reinforced concrete and un bonded post-tensioning systems of Class CC containments, as defined by CC-1000. The program also includes testing of the tendon corrosion protection medium and the pH of free water. Subsection IWL exempts from examination portions of the concrete containment that are inaccessible (e.g., concrete covered by liner, foundation material, or backfill or obstructed by adjacent structures or other components).
10 CFR 50.55a(b)(2)(viii) specifies additional requirements for inaccessible areas. It states that the licensee is to evaluate the acceptability of concrete in inaccessible areas when conditions exist in accessible areas that could indicate the presence of or result in degradation to such inaccessible areas. Steel liners for concrete containments and their integral attachments are not within the scope of Subsection IWL but are included within the scope of Subsection IWE. Subsection IWE is evaluated in AMP XI.S1.
- 2. Preventive Action: ASME Code Section XI, Subsection IWL is a condition monitoring program. However, the program includes actions to prevent or minimize corrosion of the prestressing tendons by maintaining corrosion protection medium chemistry within acceptable limits specified in IWL.
21 Refer to the GALL Report, Chapter I, for applicability of other editions of the ASME Code,Section XI.
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- 3. Parameters Monitored or Inspected: Table IWL-2500-1 specifies two categories for examination of concrete surfaces: Category L-A for all accessible concrete surfaces and Category L-B for concrete surfaces surrounding anchorages of tendons selected for testing in accordance with IWL-2521. Both of these categories rely on visual examination methods.
Concrete surfaces are examined for evidence of damage or degradation, such as concrete cracks. IWL-2510 specifies that concrete surfaces are examined for conditions indicative of degradation, such as those defined in ACI 201.1 Rand ACI 349.3R. Table IWL-2500-1 also specifies Category L-B for test and examination requirements for un bonded post tensioning systems. The number of tendons selected for examination is in accordance with Table IWL-2521-1. Additional augmented examination requirements for post-tensioning system repair/replacement activities are to be in accordance with Table IWL-2521-2. Tendon anchorage and wires or strands are visually examined for cracks, corrosion, and mechanical damage. Tendon wires or strands are also tested for yield strength, ultimate tensile strength, and elongation. The tendon corrosion protection medium is tested by analysis for alkalinity, water content, and soluble ion concentrations. The pH of free water samples is analyzed.
- 4. Detection of Aging Effects: The frequency and scope of examinations specified in 10 CFR 50.55a and Subsection IWL ensure that aging effects would be detected before they would compromise the design-basis requirements. The frequency of inspection is specified in IWL-2400. Concrete inspections are performed in accordance with Examination Category L-A. Under Subsection IWL, inservice inspections of concrete and un bonded post-tensioning systems are required at 1, 3, and 5 years following the initial structural integrity test. Thereafter, inspections are performed at 5-year intervals. For sites with multiple plants, the schedule for inservice inspection is provided in IWL-2421. In the case of tendons, only a sample of the tendons of each tendon type requires examination during each inspection.
The tendons to be examined during an inspection are selected on a random basis.
Regarding detection methods for aging effects, all accessible concrete surfaces receive General Visual examination (as defined by the ASME Code). Selected areas, such as those that indicate suspect conditions and concrete surface areas surrounding tendon anchorages (Category L-B), receive a more rigorous Detailed Visual examination (as defined by the ASME Code). Prestressing forces in sample tendons are measured. In addition, one sample tendon of each type is detensioned. A single wire or strand is removed from each detensioned tendon for examination and testing. These visual examination methods and testing would identify the aging effects of accessible concrete components and prestressing systems in concrete containments. Examination of corrosion protection medium and free water are tested for each examined tendon as specified in Table IWL-2525-1.
- 5. Monitoring and Trending: Except in inaccessible areas, all concrete surfaces are monitored on a regular basis by virtue of the examination requirements. For prestressed containments, trending of prestressing forces in tendons is required in accordance with paragraph (b)(2)(viii) of 10 CFR 50.55a. In addition to the random sampling used for tendon examination, one tendon of each type is selected from the first-year inspection sample and designated as a common tendon. Each common tendon is then examined during each inspection. Corrosion protection medium chemistry and free water pH are monitored for each examined tendon. This procedure provides monitoring and trending information over the life of the plant. 10 CFR 50.55a and Subsection IWL also require that prestressing forces in all inspection sample tendons be measured by lift-off tests and compared with acceptance standards based on the predicted force for that type of tendon over its life.
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- 6. Acceptance Criteria: IWL-3000 provides acceptance criteria for concrete containments. For concrete surfaces, the acceptance criteria rely on the determination of the "Responsible Engineer" (as defined by the ASME Code) regarding whether there is any evidence of damage or degradation sufficient to warrant further evaluation or repair. The acceptance criteria are qualitative; guidance is provided in IWL-2510, which references ACI 201.1 Rand ACI 349.3R for identification of concrete degradation. IWL-2320 requires that the Responsible Engineer be a registered professional engineer experienced in evaluating the inservice condition of structural concrete and knowledgeable of the design and construction codes and other criteria used in design and construction of concrete containments.
Quantitative acceptance criteria based on the "Evaluation Criteria" provided in Chapter 5 of ACI 349.3R also may be used to augment the qualitative assessment of the Responsible Engineer.
The acceptance standards for the un bonded post-tensioning system are quantitative in nature. For the post-tensioning system, quantitative acceptance criteria are given for tendon force and elongation, tendon wire or strand samples, and corrosion protection medium. Free water in the tendon anchorage areas is not acceptable, as specified in IWL-3221.3. If free water is found, the recommendations in Table IWL-2525-1 are followed. 10 CFR 50.55a and Subsection IWL do not define the method for calculating predicted tendon prestressing forces for comparison to the measured tendon lift-off forces. The predicted tendon forces are calculated in accordance with Regulatory Guide 1.35.1, which provides an acceptable methodology for use through the period of extended operation.
- 7. Corrective Actions: Subsection IWL specifies that items for which examination results do not meet the acceptance standards are to be evaluated in accordance with IWL-3300, "Evaluation," and described in an engineering evaluation report. The report is to include an evaluation of whether the concrete containment is acceptable without repair of the item and, if repair is required, the extent, method, and completion date of the repair or replacement.
The report also identifies the cause of the condition and the extent, nature, and frequency of additional examinations. Subsection IWL also provides repair procedures to follow in IWL-4000. This includes requirements for the concrete repair, repair of reinforcing steel, and repair of the post-tensioning system. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the corrective actions.
- 8. Confirmation Process: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the confirmation process.
- 9. Administrative Controls: IWA-1400 specifies the preparation of plans, schedules, and inservice inspection summary reports. In addition, written examination instructions and procedures, verification of qualification level of personnel who perform the examinations, and documentation of a quality assurance program are specified. IWA-6000 specifically covers the preparation, submittal, and retention of records and reports. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the administrative controls.
- 10. Operating Experience: ASME Section XI, Subsection IWL was incorporated into 10 CFR 50.55a in 1996. Prior to this time, the prestressing tendon inspections were performed in accordance with the guidance provided in Regulatory Guide 1.35. Operating experience pertaining to degradation of reinforced concrete in concrete containments was December 201 0 XI S2-3 NUREG-1801, Rev. 2 OAG10001390_00702
gained through the inspections required by 10 CFR Part 50, Appendix J, and ad hoc inspections conducted by licensees and the Nuclear Regulatory Commission (NRC).
NUREG-1522 described instances of cracked, spalled, and degraded concrete for reinforced and prestressed concrete containments. The NUREG also described cracked anchor heads for the prestressing tendons at three prestressed concrete containments.
NRC Information Notice 99-10 described occurrences of degradation in prestressing systems. The program is to consider the degradation concerns described in these generic communications. Implementation of Subsection IWL, in accordance with 10 CFR 50.55a, is a necessary element of aging management for concrete containments through the period of extended operation.
References 10 CFR Part 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
10 CFR Part 50, Appendix J, Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors, Office of the Federal Register, National Archives and Records Administration, 2009.
10 CFR 50.55a, Codes and Standards, Office of the Federal Register, National Archives and Records Administration, 2009.
ACI Standard 201.1 R, Guide for Making a Condition Survey of Concrete in Service, American Concrete Institute.
ACI Standard 349.3R, Evaluation of Existing Nuclear Safety-Related Concrete Structures, American Concrete Institute, 2002.
ASME Section XI, Rules for In service Inspection of Nuclear Power Plant Components, Subsection IWA, General Requirements, The ASME Boiler and Pressure Vessel Code, 2004 edition as approved in 10 CFR 50.55a, The American Society of Mechanical Engineers, New York, NY.
ASME Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, Subsection IWE, Requirements for Class MC and Metallic Liners of Class CC Components of Light-Water Cooled Power Plants, The ASME Boiler and Pressure Vessel Code, 2004 edition as approved in 10 CFR 50.55a, The American Society of Mechanical Engineers, New York, NY.
ASME Section XI, Rules for In service Inspection of Nuclear Power Plant Components, Subsection IWL, Requirements for Class CC Concrete Components of Light-Water Cooled Power Plants, The ASME Boiler and Pressure Vessel Code, 2004 edition as approved in 10 CFR 50.55a, The American Society of Mechanical Engineers, New York, NY.
NRC Information Notice 99-10, Revision 1, Degradation of Prestressing Tendon Systems in Prestressed Concrete Containment, U.S. Nuclear Regulatory Commission, October 7, 1999.
NRC Regulatory Guide 1.35.1, Determining Prestressing Forces for Inspection of Prestressed Concrete Containments, U.S. Nuclear Regulatory Commission, July 1990.
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NRC Regulatory Guide 1.35, Inservice Inspection of Ungrouted Tendons in Prestressed Concrete Containments, U.S. Nuclear Regulatory Commission, July 1990 NUREG-1522, Assessment of Inservice Condition of Safety-Related Nuclear Power Plant Structures, June 1995.
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NUREG-1801, Rev. 2 XI S2-6 December 201 0 OAGI0001390_00705
XI.S3 ASME SECTION XI, SUBSECTION IWF Program Description 10 CFR 50.55a imposes the inservice inspection requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI, for Class 1,2,3, and metal containment (MC) piping and components and their associated supports. Inservice inspection of supports for ASME piping and components is addressed in Section XI, Subsection IWF. This evaluation covers the 2004 edition22 of the ASME Code as approved in 10 CFR 50.55a. ASME Code,Section XI, Subsection IWF, constitutes an existing mandated program applicable to managing aging of ASME Class 1,2, 3, and MC component supports for license renewal.
The IWF scope of inspection for supports is based on sampling of the total support population.
The sample size varies depending on the ASME Class. The largest sample size is specified for the most critical supports (ASME Class 1). The sample size decreases for the less critical supports (ASME Class 2 and 3). Discovery of support deficiencies during regularly scheduled inspections triggers an increase of the inspection scope in order to ensure that the full extent of deficiencies is identified. The primary inspection method employed is visual examination.
Degradation that potentially compromises support function or load capacity is identified for evaluation. IWF specifies acceptance criteria and corrective actions. Supports requiring corrective actions are re-examined during the next inspection period.
The requirements of subsection IWF are augmented to include monitoring of high-strength structural bolting (actual measured yield strength greater than or equal to 150 ksi or 1,034 MPa) for cracking. The program is augmented to incorporate recommendations delineated in NUREG-1339 and industry recommendations delineated in the Electric Power Research Institute (EPRI)
NP-5769, NP-5067, and TR-104213 for high-strength structural bolting, if applicable. These recommendations emphasize proper selection of bolting material, lubricants, and installation torque or tension to prevent or minimize loss of bolting preload and cracking of high-strength bolting.
Evaluation and Technical Basis
- 1. Scope of Program: This program addresses supports for ASME Class 1, 2, and 3 piping and components supports that are not exempt from examination in accordance with IWF -
1230 and MC supports. The scope of the program includes support members, structural bolting, high strength structural bolting, support anchorage to the building structure, accessible sliding surfaces, constant and variable load spring hangers, guides, stops, and vibration isolation elements.
- 2. Preventive Action: Selection of bolting material and the use of lubricants and sealants is in accordance with the guidelines of EPRI NP-5769, EPRI TR-104213, and the additional recommendations of NUREG-1339 to prevent or mitigate degradation and failure of safety-related bolting. Operating experience and laboratory examinations show that the use of molybdenum disulfide (MoS2) as a lubricant is a potential contributor to stress corrosion cracking (SCC), especially when applied to high strength bolting. Thus, molybdenum disulfide and other lubricants containing sulfur should not be used. Preventive measures also include using bolting material that has an actual measured yield strength less than 22 Refer to the GALL Report, Chapter I, for applicability of other editions of the ASME Code,Section XI.
December 201 0 XI S3-1 NUREG-1801, Rev. 2 OAG10001390_00706
150 ksi or 1,034 MPa. Structural bolting replacement and maintenance activities include appropriate preload and proper tightening (torque or tension) as recommended in EPRI documents, American Society for Testing of Materials (ASTM) standards, American Institute of Steel Construction (AISC) Specifications, as applicable. If the structural bolting consists of ASTM A325, ASTM F1852, and/or ASTM A490 bolts, the preventive actions for storage, lubricants, and stress corrosion cracking potential discussed in Section 2 of RCSC (Research Council for Structural Connections) publication "Specification for Structural Joints Using ASTM A325 or A490 Bolts" need to be used.
- 3. Parameters Monitored or Inspected: The parameters monitored or inspected include corrosion; deformation; misalignment of supports; missing, detached, or loosened support items; improper clearances of guides and stops; and improper hot or cold settings of spring supports and constant load supports. Accessible areas of sliding surfaces are monitored for debris, dirt, or indications of excessive loss of material due to wear that could prevent or restrict sliding as intended in the design basis of the support. Elastomeric vibration isolation elements are monitored for cracking, loss of material, and hardening. Structural bolts are monitored for corrosion and loss of integrity of bolted connections due to self loosening and material conditions that can affect structural integrity. High-strength structural bolting (actual measured yield strength greater than or equal to 150 ksi or 1,034 MPa) susceptible to SCC should be monitored for SCC.
- 4. Detection of Aging Effects: The program requires that a sample of ASME Class 1,2, and 3 component supports that are not exempt from examination and 100% of MC component supports be examined as specified in Table IWF-2500-1. The sample size examined for ASME Class 1, 2, and 3 component supports is as specified in Table IWF-2500-1. The extent, frequency, and examination methods are designed to detect, evaluate, or repair age-related degradation before there is a loss of component support intended function. The VT-3 examination method specified by the program can reveal loss of material due to corrosion and wear, verification of clearances, settings, physical displacements, loose or missing parts, debris or dirt in accessible areas of the sliding surfaces, or loss of integrity at bolted connections. The VT-3 examination can also detect loss of material and cracking of elastomeric vibration isolation elements. VT-3 examination of elastomeric vibration isolation elements should be supplemented by feel to detect hardening if the vibration isolation function is suspect. IWF-3200 specifies that visual examinations that detect surface flaws which exceed acceptance criteria may be supplemented by either surface or volumetric examinations to determine the character of the flaw.
For high strength structural bolting (actual measured yield strength greater than or equal to 150 ksi or 1,034 MPa) in sizes greater than 1 inch nominal diameter, volumetric examination comparable to that of ASME Code Section XI, Table IWB-2500-1, Examination Category B-G-1 should be performed to detect cracking in addition to the VT-3 examination. This volumetric examination may be waived with adequate plant-specific justification. Other structural bolting (ASTM A-325, ASTM F1852, and ASTM A490 bolts) and anchor bolts are monitored for loss of material, loose or missing nuts, and cracking of concrete around the anchor bolts.
- 5. Monitoring and Trending: The ASME Class 1,2,3, and MC component supports are examined periodically, as specified in Table IWF-2500-1. As required by IWF-2420(a), the sequence of component support examinations established during the first inspection interval is repeated during each successive inspection interval, to the extent practical. Component supports whose examinations do not reveal unacceptable degradations are accepted for NUREG-1801, Rev. 2 XI S3-2 December 201 0 OAG10001390_00707
continued service. Verified changes of conditions from prior examination are recorded in accordance with IWA-6230. Component supports whose examinations reveal unacceptable conditions and are accepted for continued service by corrective measures or repair/
replacement activity are reexamined during the next inspection period. When the reexamined component support no longer requires additional corrective measures during the next inspection period, the inspection schedule may revert to its regularly scheduled inspection. Examinations that reveal indications which exceed the acceptance standards and require corrective measures are extended to include additional examinations in accordance with IWF-2430.
- 6. Acceptance Criteria: The acceptance standards for visual examination are specified in IWF-3400. IWF-3410(a) identifies the following conditions as unacceptable:
(a) Deformations or structural degradations of fasteners, springs, clamps, or other support items; (b) Missing, detached, or loosened support items, including bolts and nuts; (c) Arc strikes, weld spatter, paint, scoring, roughness, or general corrosion on close tolerance machined or sliding surfaces; (d) Improper hot or cold positions of spring supports and constant load supports; (e) Misalignment of supports; and (f) Improper clearances of guides and stops.
Other unacceptable conditions include:
(a) Loss of material due to corrosion or wear, which reduces the load bearing capacity of the component support; (b) Debris, dirt, or excessive wear that could prevent or restrict sliding of the sliding surfaces as intended in the design basis of the support; (c) Cracked or sheared bolts, including high strength bolts, and anchors; and (d) Loss of material, cracking, and hardening of elastomeric vibration isolation elements that could reduce the vibration isolation function.
The above conditions may be accepted provided the technical basis for their acceptance is documented.
- 7. Corrective Actions: Identification of unacceptable conditions triggers an expansion of the inspection scope, in accordance with IWF-2430, and reexamination of the supports requiring corrective actions during the next inspection period, in accordance with IWF-2420(b). In accordance with IWF-3122, supports containing unacceptable conditions are evaluated or tested or corrected before returning to service. Corrective actions are delineated in IWF-3122.2. IWF-3122.3 provides an alternative for evaluation or testing to substantiate structural integrity and/or functionality. As discussed in the Appendix for GALL, the staff December 201 0 XI S3-3 NUREG-1801, Rev. 2 OAGI0001390_00708
finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions.
- 8. Confirmation Process: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the confirmation process.
- 9. Administrative Controls: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the administrative controls.
- 10. Operating Experience: To date, IWF sampling inspections have been effective in managing aging effects for ASME Class 1,2, 3, and MC supports. There is reasonable assurance that the Subsection IWF inspection program will be effective in managing the aging of the in-scope component supports through the period of extended operation.
Degradation of threaded bolting and fasteners has occurred from boric acid corrosion, SCC, and fatigue loading (NRC IE Bulletin 82-02, NRC Generic Letter 91-17). SCC has occurred in high strength bolts used for NSSS component supports (EPRI NP-5769).
References 10 CFR Part 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
10 CFR 50.55a, Codes and Standards, Office of the Federal Register, National Archives and Records Administration, 2009.
ASME Section XI, Rules for In service Inspection of Nuclear Power Plant Components, Subsection IWB, Requirements for Class 1 Components of Light-Water Cooled Power Plants, The ASME Boiler and Pressure Vessel Code, 2004 edition as approved in 10 CFR 50.55a, The American Society of Mechanical Engineers, New York, NY.
ASME Section XI, Rules for In service Inspection of Nuclear Power Plant Components, Subsection IWC, Requirements for Class 2 Components of Light-Water Cooled Power Plants, The ASME Boiler and Pressure Vessel Code, 2004 edition as approved in 10 CFR 50.55a, The American Society of Mechanical Engineers, New York, NY.
ASME Section XI, Rules for In service Inspection of Nuclear Power Plant Components, Subsection IWD, Requirements for Class 3 Components of Light-Water Cooled Power Plants, The ASME Boiler and Pressure Vessel Code, 2004 edition as approved in 10 CFR 50.55a, The American Society of Mechanical Engineers, New York, NY.
ASME Section XI, Rules for In service Inspection of Nuclear Power Plant Components, Subsection IWE, Requirements for Class MC and Metallic Liners of Class CC Components of Light-Water Cooled Power Plants, The ASME Boiler and Pressure Vessel Code, 2004 edition as approved in 10 CFR 50.55a, The American Society of Mechanical Engineers, New York, NY.
ASME Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, Subsection IWF, Requirements for Class 1, 2, 3, and MC Component Supports of Light-NUREG-1801, Rev. 2 XI S3-4 December 201 0 OAG10001390_00709
Water Cooled Power Plants, The ASME Boiler and Pressure Vessel Code, 2004 edition as approved in 10 CFR 50.55a, The American Society of Mechanical Engineers, New York, NY.
EPRI NP-5067, Good Bolting Practices, A Reference Manual for Nuclear Power Plant Maintenance Personnel, Volume 1: Large Bolt Manual, 1987; Volume 2: Small Bolts and Threaded Fasteners, Electric Power Research Institute, 1990.
EPRI NP-5769, Degradation and Failure of Bolting in Nuclear Power Plants, Volumes 1 and 2, Electric Power Research Institute, April 1988.
EPRI TR-104213, Bolted Joint Maintenance & Application Guide, Electric Power Research Institute, December 1995.
NRC Generic Letter 91-17, Generic Safety Issue 79, Bolting Degradation or Failure in Nuclear Power Plants, U.S. Nuclear Regulatory Commission, October 17, 1991.
NRC Morning Report, Failure of Safety/Relief Valve Tee-Quencher Support Bolts, March 14, 2005. (ADAMS Accession Number ML050730347)
N U REG-1339, Resolution of Generic Safety Issue 29: Bolting Degradation or Failure in Nuclear Power Plants, U.S. Nuclear Regulatory Commission, June 1990.
RCSC (Research Council on Structural Connections): Specification for Structural Joints Using ASTM A325 or A490 Bolts, Chicago, 2004.
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XI.S4 10 CFR PART 50, APPENDIX J Program Description As described in 10 CFR Part 50, Appendix J, containment leak rate tests are required to "assure that (a) leakage through these containments or systems and components penetrating these containments does not exceed allowable leakage rates specified in the technical specifications and (b) integrity of the containment structure is maintained during its service life."
Appendix J provides two options, Option A and Option B, either of which can be chosen to meet the requirements of a containment leakage rate test (LRT) program. Option A is prescriptive with all testing performed on specified, uniform periodic intervals. Option B is a performance-based approach. Some of the differences between these options are discussed below. More detailed information for Option B is provided in the Nuclear Regulatory Commission (NRC)
Regulatory Guide (RG) 1.163 23 and NEI 94-01 as approved by the NRC Final Safety Evaluation for the Nuclear Energy Institute (NEI) Topical Report (TR) 94-01, Revision 2.Three types of tests are performed under either Option A or Option B. Type A tests are performed to determine the overall primary containment integrated leakage rate at the loss of coolant accident peak containment pressure. Type B tests are intended to detect local leaks and to measure leakage across each pressure-containing or leakage-limiting boundary of containment penetrations.
Type C tests are intended to detect local leaks and to measure leakage across containment isolation valves installed in containment penetrations or lines penetrating containment. If Type C tests are not performed under this program, they could be included under an ASME Code,Section XI, Inservice Test Program leakage testing for systems containing the isolation valves.
Appendix J requires a general inspection of the accessible interior and exterior surfaces of the containment structure and components be performed prior to any Type A test. General Visual examinations performed in accordance with the ASME Section XI, Subsection IWE (AMP XI.S1) or ASME Section XI, Subsection IWL (AMP XI.S2) program are an acceptable substitute. The purpose of the inspection is to uncover any evidence of structural deterioration that may affect the containment structural integrity or leak-tightness. If there is evidence of structural deterioration, the Type A test is not performed until corrective action is taken in accordance with the repair/replacement procedures.
Evaluation and Technical Basis
- 1. Scope of Program: The scope of the containment LRT program includes all containment boundary pressure-retaining components.
- 2. Preventive Action: The containment LRT program is a performance monitoring program that includes no preventive actions.
- 3. Parameters Monitored or Inspected: The parameters to be monitored are leakage rates through containment shells, containment liners, and associated welds, penetrations, fittings, and other access openings.
- 4. Detection of Aging Effects: A containment LRT program is effective in detecting leakage rate of the containment pressure boundary components, including seals and gaskets. While the calculation of leakage rates and satisfactory performance of containment leakage rate 23 RG 1.163 Rev. 0 or the latest Revision.
December 201 0 XI S4-1 NUREG-1801, Rev. 2 OAG10001390_00711
testing demonstrates the leak-tightness and structural integrity of the containment, it does not by itself provide information that would indicate that aging degradation has initiated or that the capacity of the containment may have been reduced for other types of loads, such as seismic loading. This would be achieved with the additional implementation of an acceptable containment inservice inspection program as described in ASME Section XI, Subsection IWE (AMP XI.S1) and ASME Section XI, Subsection IWL (AMP XI.S2).
- 5. Monitoring and Trending: Because the LRT program is repeated throughout the operating license period, the entire pressure boundary is monitored over time. The frequency of these tests depends on which option (A or B) is selected. With Option A, testing is performed on a regular fixed time interval as defined in 10 CFR Part 50, Appendix J. In the case of Option B, the interval for testing may be adjusted on the basis of acceptable performance in meeting leakage limits in prior tests. Additional details for implementing Option B are provided in NRC RG 1.163 and NEI 94-01.
- 6. Acceptance Criteria: Acceptance criteria for leakage rates are defined in plant technical specifications. These acceptance criteria meet the requirements in 10 CFR Part 50, Appendix J, and are part of each plant's current licensing basis.
- 7. Corrective Actions: Corrective actions are taken in accordance with 10 CFR Part 50, Appendix J, and NEI 94-01. When leakage rates do not meet the acceptance criteria, an evaluation is performed to identify the cause of the unacceptable performance and appropriate corrective actions are taken. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions.
- 8. Confirmation Process: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the confirmation process.
- 9. Administrative Controls: Results of the LRT program are documented as described in 10 CFR Part 50, Appendix J, to demonstrate that the acceptance criteria for leakage have been satisfied. The test results that exceed the performance criteria are assessed under 10 CFR 50.72 and 10 CFR 50.73. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the administrative controls.
- 10. Operating Experience: To date, the 10 CFR Part 50, Appendix J, LRT program, in conjunction with the containment inservice inspection program, has been effective in preventing unacceptable leakage through the containment pressure boundary.
Implementation of Option B for testing frequency must be consistent with plant-specific operating experience.
References 10 CFR Part 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
10 CFR Part 50, Appendix J, Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors, Office of the Federal Register, National Archives and Records Administration, 2009.
NUREG-1801, Rev. 2 XI S4-2 December 201 0 OAG10001390_00712
10 CFR 50.72, Immediate Notification Requirements for Operating Nuclear Power Reactors, Office of the Federal Register, National Archives and Records Administration, 2009.
10 CFR 50.73, Licensee Event Report System, Office of the Federal Register, National Archives and Records Administration, 2009.
Final Safety Evaluation for 'Nuclear Energy Institute (NEI) Topical Report (TR) 94-01, Revision 2, Industry Guideline for Implementing Performance-Based Option of 10 CFR, Part 50, Appendix J,' and 'Electric Power Research Institute (EPRI) Report No. 1009325, Revision 2, Risk Impact Assessment of Extended Integrated Leak Rate Testing Intervals, August 2007,'
June 25,2008.
NEI 94-01, Rev. 2-A, Industry Guideline for Implementing Performance-Based Option of 10 CFR Part 50 Appendix J, Nuclear Energy Institute, August 2007.
NRC Regulatory Guide 1.163, Rev. 0, Performance-Based Containment Leak- Test Program, U.S. Nuclear Regulatory Commission, September 1995.
December 201 0 XI S4-3 NUREG-1801, Rev. 2 OAG10001390_00713
XI.S5 MASONRY WALLS Program Description Nuclear Regulatory Commission (NRC) IE Bulletin (lEB) 80-11, "Masonry Wall Design," and NRC Information Notice (IN) 87-67, "Lessons Learned from Regional Inspections of Licensee Actions in Response to IE Bulletin 80-11," constitute an acceptable basis for a masonry wall aging management program (AMP). IEB 80-11 required (a) the identification of masonry walls in close proximity to or having attachments from safety-related systems or components and (b) the evaluation of design adequacy and construction practice. NRC IN 87-67 recommended plant-specific condition monitoring of masonry walls and administrative controls to ensure that the evaluation basis developed in response to NRC IEB 80-11 is not invalidated by (a) deterioration of the masonry walls (e.g., new cracks not considered in the reevaluation), (b) physical plant changes such as installation of new safety-related systems or components in close proximity to masonry walls, or (c) reclassification of systems or components from non-safety-related to safety-related, provided appropriate evaluation is performed to account for such occurrences.
Important elements in the evaluation of many masonry walls during the NRC IEB 80-11 program included (a) installation of steel edge supports to provide a sound technical basis for boundary conditions used in seismic analysis and (b) installation of steel bracing to ensure stability or containment of unreinforced masonry walls during a seismic event. Consequently, in addition to the development of cracks in the masonry walls, loss of function of the structural steel supports and bracing would also invalidate the evaluation basis. The steel edge supports and steel bracings are considered component supports and aging effects are managed by the Structures Monitoring program (AMP XI.S6).
The program requires periodic visual inspection of masonry walls in the scope of license renewal to detect loss of material and cracking of masonry units and mortar. The aging effects that could impact masonry wall intended function or potentially invalidate its evaluation basis are entered in the corrective action process for further analysis, repair, or replacement.
Since the issuance of NRC IEB 80-11 and NRC IN 87-67, the NRC promulgated 10 CFR 50.65, the Maintenance Rule. For license renewal, masonry walls may be inspected as part of the "Structures Monitoring Program" (AMP XI.S6) conducted for the Maintenance Rule, provided the 10 attributes described below are incorporated in AMP XI.S6. The aging effects on masonry walls that are considered fire barriers also are managed by AMP XI.M26, Fire Protection.
Evaluation and Technical Basis
- 1. Scope of Program: The scope includes all masonry walls identified as performing intended functions in accordance with 10 CFR 54.4. The aging effects on masonry walls that are considered fire barriers also are managed by AMP XI.M26, Fire Protection, as well as being managed by this program.
- 2. Preventive Action: This is a condition monitoring program and no specific preventive actions are required.
- 3. Parameters Monitored or Inspected: The primary parameters monitored are potential shrinkage and/or separation and cracking of masonry walls and gaps between the supports and masonry walls that could impact the intended function or potentially invalidate its evaluation basis.
December 201 0 XI S5-1 NUREG-1801, Rev. 2 OAG10001390_00714
- 4. Detection of Aging Effects: Visual examination of the masonry walls by qualified inspection personnel is sufficient. In general, masonry walls should be inspected every 5 years, with provisions for more frequent inspections in areas where significant loss of material or cracking is observed to ensure there is no loss of intended function between inspections. However, masonry walls that are fire barriers are visually inspected in accordance with AMP XI.M26.
- 5. Monitoring and Trending: Trending is not required. Condition monitoring for evidence of shrinkage and/or separation and cracking is achieved by periodic examination. Degradation detected from monitoring is evaluated.
- 6. Acceptance Criteria: For each masonry wall, the extent of observed shrinkage and/or separation and cracking of masonry may not invalidate the evaluation basis or impact the wall's intended function. However, further evaluation is conducted if the extent of cracking and loss of material is sufficient to impact the intended function of the wall or invalidate its evaluation basis.
- 7. Corrective Actions: A corrective action option is to develop a new analysis or evaluation basis that accounts for the degraded condition of the wall (i.e., acceptance by further evaluation). Other alternatives include repair or replacing the degraded wall. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions.
- 8. Confirmation Process: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the confirmation process.
- 9. Administrative Controls: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the administrative controls.
- 10. Operating Experience: Since 1980, masonry walls that perform an intended function have been systematically identified through licensee programs in response to NRC IEB 80-11, NRC Generic Letter 87-02, and 10 CFR 50.48. NRC IN 87-67 documented lessons learned from the NRC IEB 80-11 program and provided recommendations for administrative controls and periodic inspection to ensure that the evaluation basis for each safety-significant masonry wall is maintained. NUREG-1522 documents instances of observed cracks and other deterioration of masonry-wall joints at nuclear power plants. Whether conducted as a stand-alone program or as a part of structures monitoring, a masonry wall AMP that incorporates the recommendations delineated in NRC IN 87-67 should ensure that the intended functions of all masonry walls within the scope of license renewal are maintained for the period of extended operation.
References 10 CFR Part 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
10 CFR 50.48, Fire Protection, Office of the Federal Register, National Archives and Records Administration, 2009.
NUREG-1801, Rev. 2 XI S5-2 December 201 0 OAG10001390_00715
10 CFR 50.65, Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
10 CFR 54.4, Scope, Office of the Federal Register, National Archives and Records Administration, 2009.
NRC Generic Letter 87-02, Verification of Seismic Adequacy of Mechanical and Electrical Equipment in Operating Reactors, Unresolved Safety Issue (USI) A-46, U.S. Nuclear Regulatory Commission, February 19, 1987.
NRC IE Bulletin 80-11, Masonry Wall Design, U.S. Nuclear Regulatory Commission, May 8,1980.
NRC Information Notice 87-67, Lessons Learned from Regional Inspections of Licensee Actions in Response to IE Bulletin 80-11, U.S. Nuclear Regulatory Commission, December 31, 1987.
NRC Regulatory Guide 1.160, Rev. 2, Monitoring the Effectiveness of Maintenance at Nuclear Power Plants, U.S. Nuclear Regulatory Commission, March 1997.
NUMARC 93-01, Rev. 2, Industry Guideline for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants (Line-lnILine-Out Version), Nuclear Energy Institute, April 1996.
NUREG-1522, Assessment of Inservice Condition of Safety-Related Nuclear Power Plant Structures, June 1995.
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XI.S6 STRUCTURES MONITORING Program Description Implementation of structures monitoring under 10 CFR 50.65 (the Maintenance Rule) is addressed in Nuclear Regulatory Commission (NRC) Regulatory Guide (RG) 1.160, Rev. 2, and NUMARC 93-01, Rev. 2. These two documents provide guidance for development of licensee-specific programs to monitor the condition of structures and structural components within the scope of the Maintenance Rule, such that there is no loss of structure or structural component intended function.
The structures monitoring program consists of periodic visual inspections by personnel qualified to monitor structures and components for applicable aging effects, such as those described in the American Concrete Institute Standards (ACI) 349.3R, ACI 201.1 R, and American National Standards Institute/American Society of Civil Engineers Standard (ANSI/ASCE) 11. Visual inspections should be supplemented with volumetric or surface examinations to detect stress corrosion cracking (SCC) in high strength (actual measured yield strength greater than or equal to 150 kilo-pound per square inch [ksi] or greater than or equal to 1,034 MPa) structural bolts greater than 1 inch (25 mm) in diameter. Identified aging effects are evaluated by qualified personnel using criteria derived from industry codes and standards contained in the plant current licensing bases, including ACI 349.3R, ACI 318, ANSI/ASCE 11, and the American Institute of Steel Construction (AISC) specifications, as applicable.
The program includes preventive actions delineated in NUREG-1339 and in Electric Power Research Institute (EPRI) NP-5769, NP-5067, and TR-104213 to ensure structural bolting integrity, if applicable.
The program also includes periodic sampling and testing of ground water and the need to assess the impact of any changes in its chemistry on below grade concrete structures.
If protective coatings are relied upon to manage the effects of aging for any structures included in the scope of this aging management program (AMP), the structures monitoring program is to address protective coating monitoring and maintenance.
Evaluation and Technical Basis
- 1. Scope of Program: The scope of the program includes all structures, structural components, component supports, and structural commodities in the scope of license renewal that are not covered by other structural AMPs (i.e., "ASME Section XI, Subsection IWE" (AMP XI.S1); "ASME Section XI, Subsection IWL" (AMP XI.S2); "ASME Section XI, Subsection IWF" (AMP XI.S3); "Masonry Walls" (AMP XI.S5); and NRC RG 1.127, "Inspection of Water-Control Structures Associated with Nuclear Power Plants" (AMP XI.S7).
Examples of structures, structural components, and commodities in the scope of the program are concrete and steel structures, structural bolting, anchor bolts and embedments, component support members, pipe whip restraints and jet impingement shields, transmission towers, panels and other enclosures, racks, sliding surfaces, sump and pool liners, electrical cable trays and conduits, trash racks associated with water control structures, electrical duct banks, manholes, doors, penetration seals, and tube tracks. The applicant is to specify other structures or components that are in the scope of its structures monitoring program. The scope of this program includes periodic sampling and testing of ground water and may include inspection of masonry walls and water-control structures December 201 0 XI S6-1 NUREG-1801, Rev. 2 OAG10001390_00717
provided all the attributes of "Masonry Walls" (AMP XI.S5) and NRC RG 1.127, "Inspection of Water-Control Structures Associated with Nuclear Power Plants" (AMP XI.S7) are incorporated in the attributes of this program.
- 2. Preventive Action: The structures monitoring program is a condition monitoring program.
The program should include preventive actions delineated in NUREG-1339 and in EPRI NP-5769, NP-5067, and TR-104213 to ensure structural bolting integrity, if applicable. These actions emphasize proper selection of bolting material, lubricants, and installation torque or tension to prevent or minimize loss of bolting preload and cracking of high strength bolting. If the structural bolting consists of ASTM A325, ASTM F1852, and/or ASTM A490 bolts, the preventive actions for storage, lubricants, and stress corrosion cracking potential discussed in Section 2 of RCSC (Research Council for Structural Connections) publication "Specification for Structural Joints Using ASTM A325 or A490 Bolts," need to be used.
- 3. Parameters Monitored or Inspected: For each structure/aging effect combination, the specific parameters monitored or inspected depend on the particular structure, structural component, or commodity. Parameters monitored or inspected are commensurate with industry codes, standards, and guidelines and also consider industry and plant-specific operating experience. ACI 349.3R and ANSI/ASCE 11 provide an acceptable basis for selection of parameters to be monitored or inspected for concrete and steel structural elements and for steel liners, joints, coatings, and waterproofing membranes (if applicable).
For concrete structures, parameters monitored include loss of material, cracking, increase in porosity and permeability, loss of foundation strength, and reduction in concrete anchor capacity due to local concrete degradation. Steel structures and components are monitored for loss of material due to corrosion. Structural bolting is monitored for loose bolts, missing or loose nuts, and other conditions indicative of loss of preload. High strength (actual measured yield strength 2:: 150 ksi or 1,034 MPa) structural bolts greater than 1 inch (25 mm) in diameter are monitored for SCC. Other structural bolting (ASTM A-325, ASTM F1852, and ASTM A490 bolts), and anchor bolts are monitored for loss of material, loose or missing nuts, and cracking of concrete around the anchor bolts. Accessible sliding surfaces are monitored for indication of significant loss of material due to wear or corrosion, debris, or dirt. Elastomeric vibration isolators and structural sealants are monitored for cracking, loss of material, and hardening. These parameters and other monitored parameters are selected to ensure that aging degradation leading to loss of intended functions will be detected and the extent of degradation can be determined. Ground water chemistry (pH, chlorides, and sulfates) are monitored periodically to assess its impact, if any, on below grade concrete structures. If necessary for managing settlement and erosion of porous concrete sub-foundations, the continued functionality of a site de-watering system is monitored. The plant-specific structures monitoring program should contain sufficient detail on parameters monitored or inspected to conclude that this program attribute is satisfied.
- 4. Detection of Aging Effects: Structures are monitored under this program using periodic visual inspection of each structure/aging effect combination by a qualified inspector to ensure that aging degradation will be detected and quantified before there is loss of intended function. Visual inspection of high strength (actual measured yield strength 2:: 150 ksi or 1,034 MPa) structural bolting greater than 1 inch (25 mm) in diameter is supplemented with volumetric or surface examinations to detect cracking. Other structural bolting (ASTM A-325, ASTM F1852, and ASTM A490 bolts) and anchor bolts are monitored for loss of material, loose or missing nuts, and cracking of concrete around the anchor bolts.
Accessible sliding surfaces are monitored for indication of significant loss of material due to NUREG-1801, Rev. 2 XI S6-2 December 201 0 OAG10001390_00718
wear or corrosion, debris, or dirt. Visual inspection of elastomeric vibration isolation elements should be supplemented by feel to detect hardening if the vibration isolation function is suspect. The inspection frequency depends on safety significance and the condition of the structure as specified in NRC RG 1.160, Rev. 2. In general, all structures and ground water quality are monitored on a frequency not to exceed 5 years. Some structures of lower safety significance, and subjected to benign environmental conditions, may be monitored at an interval exceeding five years; however, they should be identified and listed, together with their operating experience. The program includes provisions for more frequent inspections of structures and components categorized as (a)(1) in accordance with 10 CFR 50.65. Inspector qualifications should be consistent with industry guidelines and standards and guidelines for implementing the requirements of 10 CFR 50.65. Qualifications of inspection and evaluation personnel specified in ACI 349.3R are acceptable for license renewal.
The structures monitoring program addresses detection of aging affects for inaccessible, below-grade concrete structural elements. For plants with non-aggressive ground water/soil (pH> 5.5, chlorides < 500 ppm, or sulfates <1500 ppm), the program recommends:
(a) evaluating the acceptability of inaccessible areas when conditions exist in accessible areas that could indicate the presence of, or result in, degradation to such inaccessible areas and (b) examining representative samples of the exposed portions of the below grade concrete, when excavated for any reason.
For plants with aggressive ground water/soil (pH < 5.5, chlorides> 500 ppm, or sulfates
> 1500 ppm) and/or where the concrete structural elements have experienced degradation, a plant-specific AMP accounting for the extent of the degradation experienced should be implemented to manage the concrete aging during the period of extended operation.
- 5. Monitoring and Trending: Regulatory Position 1.5, "Monitoring of Structures," in NRC RG 1.160, Rev. 2, provides an acceptable basis for meeting the attribute. A structure is monitored in accordance with 10 CFR 50.65(a)(2) provided there is no significant degradation of the structure. A structure is monitored in accordance with 10 CFR 50.65(a)(1) if the extent of degradation is such that the structure may not meet its design basis or, if allowed to continue uncorrected until the next normally scheduled assessment, may not meet its design basis.
- 6. Acceptance Criteria: The structures monitoring program calls for inspection results to be evaluated by qualified engineering personnel based on acceptance criteria selected for each structure/aging effect to ensure that the need for corrective actions is identified before loss of intended functions. The criteria are derived from design bases codes and standards that include ACI 349.3R, ACI 318, ANSI/ASCE 11, or the relevant AISC specifications, as applicable, and consider industry and plant operating experience. The criteria are directed at the identification and evaluation of degradation that may affect the ability of the structure or component to perform its intended function. Applicants who are not committed to ACI 349.3R and elect to use plant-specific criteria for concrete structures should describe the criteria and provide a technical basis for deviations from those in ACI 349.3R. Loose bolts and nuts and cracked high strength bolts are not acceptable unless accepted by engineering evaluation. Structural sealants are acceptable if the observed loss of material, cracking, and hardening will not result is loss of sealing. Elastomeric vibration isolation elements are acceptable if there is no loss of material, cracking, or hardening that could lead to the reduction or loss of isolation function. Acceptance criteria for sliding surfaces are (a) no indications of excessive loss of material due to corrosion or wear and (b) no debris or dirt December 201 0 XI S6-3 NUREG-1801, Rev. 2 OAG10001390_00719
that could restrict or prevent sliding of the surfaces as required by design. The structures monitoring program is to contain sufficient detail on acceptance criteria to conclude that this program attribute is satisfied.
- 7. Corrective Actions: Evaluations are performed for any inspection results that do not satisfy established criteria. Corrective actions are initiated in accordance with the corrective action process if the evaluation results indicate there is a need for a repair or replacement. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the corrective actions.
- 8. Confirmation Process: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the confirmation process.
- 9. Administrative Controls: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the administrative controls.
- 10. Operating Experience: Although in many plants, structures monitoring programs have only recently been implemented, plant maintenance has been ongoing since initial plant operations. N U REG-1522 documents the results of a survey sponsored in 1992 by the Office of Nuclear Regulatory Regulation to obtain information on the types of distress in the concrete and steel structures and components, the type of repairs performed, and the durability of the repairs. Licensees who responded to the survey reported cracking, scaling, and leaching of concrete structures. The degradation was attributed to drying shrinkage, freeze-thaw, and abrasion. The NUREG also describes the results of NRC staff inspections at six plants. The staff observed concrete degradation, corrosion of component support members and anchor bolts, cracks and other deterioration of masonry walls, and ground water leakage and seepage into underground structures. The observed and reported degradations were more severe at coastal plants than those observed in inland plants as a result of brackish and sea water. Previous license renewal applicants reported similar degradation and corrective actions taken through their structures monitoring program. Many license renewal applicants have found it necessary to enhance their structures monitoring program to ensure that the aging effects of structures and components in the scope of 10 CFR Part 54.4 are adequately managed during the period of extended operation. There is reasonable assurance that implementation of the structures monitoring program described above will be effective in managing the aging of the in-scope structures and component supports through the period of extended operation.
References 10 CFR Part 50, Appendix 8, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
10 CFR 50.65, Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
10 CFR 54.4, Scope, Office of the Federal Register, National Archives and Records Administration, 2009.
NUREG-1801, Rev. 2 XI S6-4 December 201 0 OAG10001390_00720
ACI Standard 201.1 R, Guide for Making a Condition Survey of Concrete in Service, American Concrete Institute, 1992.
ACI Standard 318, Building Code Requirements for Reinforced Concrete and Commentary, American Concrete Institute.
ACI Standard 349.3R, Evaluation of Existing Nuclear Safety-Related Concrete Structures, American Concrete Institute, 2002.
AISC, AISC Specification for Steel Buildings, American Institute of Steel Construction, Inc.,
Chicago, IL.
ANSI/ASCE 11-90, 99, Guideline for Structural Condition Assessment of Existing Buildings, American Society of Civil Engineers.
EPRI NP-5067, Good Bolting Practices, A Reference Manual for Nuclear Power Plant Maintenance Personnel, Volume 1: Large Bolt Manual, 1987; Volume 2: Small Bolts and Threaded Fasteners, Electric Power Research Institute, 1990.
EPRI NP-5769, Oegradation and Failure of Bolting in Nuclear Power Plants, Volumes 1 and 2, Electric Power Research Institute, April 1988.
EPRI TR-104213, Bolted Joint Maintenance & Application Guide, Electric Power Research Institute, December 1995.
RCSC (Research Council on Structural Connections), Specification for Structural Joints Using ASTM A325 or A490 Bolts, Chicago, 2004.
NRC Regulatory Guide 1.127, Rev. 1, Inspection of Water-Control Structures Associated with Nuclear Power Plants, U.S. Nuclear Regulatory Commission, March 1978.
NRC Regulatory Guide 1.142, Rev. 2, Safety-related Concrete Structures for Nuclear Power Plants (Other than Reactor Vessels and Containments), U.S. Nuclear Regulatory Commission, November 2001.
NRC Regulatory Guide 1.160, Rev. 2, Monitoring the Effectiveness of Maintenance at Nuclear Power Plants, U.S. Nuclear Regulatory Commission, March 1997.
NUMARC 93-01, Rev. 2, Industry Guideline for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants (Line-lnILine-Out Version), Nuclear Energy Institute, April 1996.
N U REG-1339, Resolution of Generic Safety Issue 29: Bolting Oegradation or Failure in Nuclear Power Plants, U.S. Nuclear Regulatory Commission, June 1990.
NUREG-1522, Assessment of Inservice Condition of Safety-Related Nuclear Power Plant Structures, June 1995.
December 201 0 XI S6-5 NUREG-1801, Rev. 2 OAG10001390_00721
XI.S7 RG 1.127, INSPECTION OF WATER-CONTROL STRUCTURES ASSOCIATED WITH NUCLEAR POWER PLANTS Program Description Nuclear Regulatory Commission (NRC) Regulatory Guide (RG) 1.127, Revision 1, "Inspection of Water-Control Structures Associated with Nuclear Power Plants," describes an acceptable basis for developing an inservice inspection and surveillance program for dams, slopes, canals, and other raw water-control structures associated with emergency cooling water systems or flood protection of nuclear power plants. The NRC RG 1.127 program addresses age-related deterioration, degradation due to extreme environmental conditions, and the effects of natural phenomena that may affect water-control structures. The NRC RG 1.127 program recognizes the importance of periodic monitoring and maintenance of water-control structures so that the consequences of age-related deterioration and degradation can be prevented or mitigated in a timely manner.
NRC RG 1.127 provides detailed guidance for the licensee's inspection program for water-control structures, including guidance on engineering data compilation, inspection activities, technical evaluation, inspection frequency, and the content of inspection reports. NRC RG 1.127 delineates current NRC practice in evaluating inservice inspection programs for water-control structures.
For plants not committed to NRC RG 1.127, Revision 1, aging management of water-control structures may be included in the "Structures Monitoring" (AMP XI.S6). Even if a plant is committed to NRC RG 1.127, Revision 1, aging management of certain structures and components may be included in the "Structures Monitoring" (AMP XI.S6). However, details pertaining to water-control structures, as described herein, are incorporated in AMP XI.S6 program attributes.
NRC RG 1.127 attributes evaluated below do not include inspection of dams. For dam inspection and maintenance, programs under the regulatory jurisdiction of the Federal Energy Regulatory Commission (FERC) or the U.S. Army Corps of Engineers, continued through the period of extended operation, are adequate for the purpose of aging management. For programs not falling under the regulatory jurisdiction of FERC or the U.S. Army Corps of Engineers, the staff evaluates the effectiveness of the aging management program (AMP) based on compatibility to the common practices of the FERC and Corps programs.
Evaluation and Technical Basis
- 1. Scope of Program: NRC RG 1.127 applies to raw water-control structures associated with emergency cooling water systems or flood protection of nuclear power plants. The water-control structures included in the RG 1.127 program are concrete structures, embankment structures, spillway structures and outlet works, reservoirs, cooling water channels and canals, and intake and discharge structures. The scope of the program also includes structural steel and structural bolting associated with water-control structures, steel or wood piles and sheeting required for the stability of embankments and channel slopes, and miscellaneous steel, such as sluice gates and trash racks.
- 2. Preventive Action: NRC RG 1.127 is a condition monitoring program. This program is augmented to incorporate preventive measures recommended in NUREG-1339, Electric Power Research Institute (EPRI) TR-104213, EPRI NP-5067, and EPRI NP-5769 to ensure December 201 0 XI S7-1 NUREG-1801, Rev. 2 OAGI0001390_00722
structural bolting integrity, if applicable. The documents provide guidelines for selection of replacement bolting material, approved thread lubricants, and appropriate torque and preload to be used for installation of bolting. If the structural bolting consists of ASTM A325, ASTM F1852, and/or ASTM A490 bolts, the preventive actions for storage, lubricants, and stress corrosion cracking potential discussed in Section 2 of RCSC (Research Council for Structural Connections) publication "Specification for Structural Joints Using ASTM A325 or A490 Bolts" need to be used.
- 3. Parameters Monitored or Inspected: NRC RG 1.127 identifies the parameters to be monitored and inspected for water-control structures. The parameters vary depending on the particular structure.
Parameters to be monitored and inspected for concrete structures are those described in American Concrete Institute (ACI) 201.1 and ACI-349-3R. These include cracking, movements (e.g., settlement, heaving, deflection), conditions at junctions with abutments and embankments, loss of material, increase in porosity and permeability, seepage, and leakage.
Parameters to be monitored and inspected for earthen embankment structures include settlement, depressions, sink holes, slope stability (e.g., irregularities in alignment and variances from originally constructed slopes), seepage, proper functioning of drainage systems, and degradation of slope protection features.
Steel components are monitored for loss of material due to corrosion.
Parameters monitored for channels and canals include erosion or degradations that may impose constraints on the function of the cooling system and present a potential hazard to the safety of the plant. Submerged emergency canals (e.g., artificially dredged canals at the river bed or the bottom of the reservoir) should be monitored for sedimentation, debris, or instability of slopes that may impair the function of the canals under extreme low flow conditions.
Further details of parameters to be monitored and inspected for these and other water-control structures are specified in Section C.2 of NRC RG 1.127. The program is augmented to require monitoring of bolted connections for loss of material and loose bolts and nuts and other conditions indicative of loss of preload. High strength (actual measured yield strength 2:: 150 ksi or 1,034 MPa) structural bolts greater than 1 inch (25 mm) in diameter are monitored for stress corrosion cracking, if applicable. Other structural bolting (ASTM A-325, ASTM F1852, and ASTM A490 bolts) and anchor bolts are monitored for loss of material, loose or missing nuts, and cracking of concrete around the anchor bolts. Accessible sliding surfaces are monitored for indication of significant loss of material due to wear or corrosion, debris, or dirt. The program also is augmented to require monitoring of wooden components for loss of material and change in material properties.
- 4. Detection of Aging Effects: NRC RG 1.127 specifies that inspection of water-control structures should be conducted under the direction of qualified engineers experienced in the investigation, design, construction, and operation of these types of facilities. Visual inspections are primarily used to detect degradation of water-control structures. In some cases, instruments have been installed to measure the behavior of water-control structures.
NRC RG 1.127 indicates that the available records and readings of installed instruments are to be reviewed to detect any unusual performance or distress that may be indicative of NUREG-1801, Rev. 2 XI S7-2 December 2010 OAG10001390_00723
degradation. NRC RG 1.127 describes periodic inspections to be performed at least once every 5 years. This interval has been shown to be adequate to detect degradation of water-control structures before a loss of an intended function. The program should include provisions for increased inspection frequency if the extent of the degradation is such that the structure or component may not meet its design basis if allowed to continue uncorrected until the next normally scheduled inspection. NRC RG 1.127 also describes special inspections immediately following the occurrence of significant natural phenomena, such as large floods, earthquakes, hurricanes, tornadoes, and intense local rainfalls.
The program should address detection of aging affects for inaccessible, below-grade, and submerged concrete structural elements. For plants with non-aggressive raw water and groundwater/soil (pH> 5.5, chlorides < 500 parts per million [ppm], or sulfates < 1500 ppm),
the program should require (a) evaluation of the acceptability of inaccessible areas when conditions exist in accessible areas that could indicate the presence of, or result in, degradation to such inaccessible areas and (b) examination of representative samples of the exposed portions of the below-grade concrete when excavated for any reason.
Submerged concrete structures should be inspected during periods of low tide or when dewatered and accessible.
For plants with aggressive environment raw water (pH < 5.5, chlorides> 500 ppm, or sulfates> 1500 ppm) or ground water/soil and/or where the concrete structural elements have experienced degradation, a plant-specific AMP accounting for the extent of the degradation experienced should be implemented to manage the concrete aging during the period of extended operation.
- 5. Monitoring and Trending: Water-control structures are monitored by periodic inspection, as described in NRC RG 1.127. Changes of degraded conditions from prior inspection, such as growth of an active crack or extent of corrosion, should be trended until it is evident that the change is no longer occurring or until corrective actions are implemented in accordance with 10 CFR 50.65 and RG 1.160, Rev. 2.
- 6. Acceptance Criteria: Quantitative acceptance criteria to evaluate the need for corrective actions are not specified in NRC RG 1.127. However, the "Evaluation Criteria" provided in Chapter 5 of ACI 349.3R provide acceptance criteria (including quantitative criteria) for determining the adequacy of observed aging effects and specifies criteria for further evaluation. Although not required, plant-specific acceptance criteria based on Chapter 5 of ACI 349.3R are acceptable. Acceptance criteria for earthen structures, such as canals and embankments, are consistent with programs falling within the regulatory jurisdiction of the FERC or the U.S. Army Corps of Engineers. Loose bolts and nuts, cracked high strength bolts, and degradation of piles and sheeting are accepted by engineering evaluation or subject to corrective actions. Engineering evaluation should be documented and based on codes, specifications, and standards such as AISC specifications, SEI/ASCE 11, and those referenced in the plant's current licensing basis.
- 7. Corrective Actions: NRC RG 1.127 recommends that when inspection findings indicate that significant changes have occurred, the conditions are to be evaluated. This includes a technical assessment of the causes of distress or abnormal conditions, an evaluation of the behavior or movement of the structure, and recommendations for remedial or mitigating measures. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the corrective actions.
December 201 0 XI S7-3 NUREG-1801, Rev. 2 OAG10001390_00724
- 8. Confirmation Process: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the confirmation process.
- 9. Administrative Controls: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the administrative controls.
- 10. Operating Experience: Degradation of water-control structures has been detected, through NRC RG 1.127 programs, at a number of nuclear power plants, and, in some cases, it has required remedial action. NRC NUREG-1522 described instances and corrective actions of severely degraded steel and concrete components at the intake structure and pumphouse of coastal plants. Other degradation described in the NUREG include appreciable leakage from the spillway gates, concrete cracking, corrosion of spillway bridge beam seats of a plant dam and cooling canal, and appreciable differential settlement of the outfall structure of another. No loss of intended functions has resulted from these occurrences. Therefore, it can be concluded that the inspections implemented in accordance with the guidance in NRC RG 1.127 have been successful in detecting significant degradation before loss of intended function occurs.
References 10 CFR Part 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
ACI Standard 201.1 R, Guide for Making a Condition Survey of Concrete in Service, American Concrete Institute, 1992.
ACI Standard 349.3R, Evaluation of Existing Nuclear Safety-Related Concrete Structures, American Concrete Institute, 2002.
EPRI NP-5067, Good Bolting Practices, A Reference Manual for Nuclear Power Plant Maintenance Personnel, Volume 1: Large Bolt Manual, 1987; Volume 2: Small Bolts and Threaded Fasteners, Electric Power Research Institute, 1990.
EPRI NP-5769, Oegradation and Failure of Bolting in Nuclear Power Plants, Volumes 1 and 2, Electric Power Research Institute, April 1988.
EPRI TR-104213, Bolted Joint Maintenance & Application Guide, Electric Power Research Institute, December 1995.
NRC Regulatory Guide 1.127, Inspection of Water-Control Structures Associated with Nuclear Power Plants, Revision 1, U.S. Nuclear Regulatory Commission, March 1978.
NRC Regulatory Guide 1.160, Rev. 2, Monitoring the Effectiveness of Maintenance at Nuclear Power Plants, U.S. Nuclear Regulatory Commission, March 1997.
N U REG-1339, Resolution of Generic Safety Issue 29: Bolting Oegradation or Failure in Nuclear Power Plants, U.S. Nuclear Regulatory Commission, June 1990.
NUREG-1801, Rev. 2 XI S7-4 December 2010 OAG10001390_00725
NUREG-1522, Assessment of Inservice Conditions of Safety-Related Nuclear Plant Structures, U.S. Nuclear Regulatory Commission, June 1995.
RCSC (Research Council on Structural Connections), Specification for Structural Joints Using ASTM A325 or A490 Bolts, 2004.
December 201 0 XI S7-5 NUREG-1801, Rev. 2 OAG10001390_00726
XI.S8 PROTECTIVE COATING MONITORING AND MAINTENANCE PROGRAM Program Description Proper maintenance of protective coatings inside containment (defined as Service Level I in Nuclear Regulatory Commission (NRC) Regulatory Guide (RG) 1.54, Rev. 1, or latest version) is essential to ensure operability of post-accident safety systems that rely on water recycled through the containment sump/drain system. Degradation of coatings can lead to clogging of Emergency Core Cooling Systems (ECCS) suction strainers, which reduces flow through the system and could cause unacceptable head loss for the pumps.
Maintenance of Service Level I coatings applied to carbon steel and concrete surfaces inside containment (e.g., steel liner, steel containment shell, structural steel, supports, penetrations, and concrete walls and floors) also serve to prevent or minimize loss of material due to corrosion of carbon steel components and aids in decontamination. Regulatory Position C4 in NRC RG 1.54, Rev. 2, describes an acceptable technical basis for a Service Levell coatings monitoring and maintenance program that can be credited for managing the effects of corrosion for carbon steel elements inside containment. American Society for Testing of Materials (ASTM)
D 5163-0S and endorsed years of the standard in NRC RG 1.54 are acceptable and considered consistent with NUREG-1S01. In addition, Electric Power Research Institute (EPRI) Report 1019157, Guidelines for Inspection and Maintenance of Safety-related Protective Coatings, provides additional information on the ASTM standard guidelines.
A comparable program for monitoring and maintaining protective coatings inside containment, developed in accordance with NRC RG 1.54, Rev. 2, is acceptable as an aging management program for license renewal.
Service Level I coatings credited for preventing corrosion of steel containments and steel liners for concrete containments are subject to requirements specified by the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code,Section XI, Subsection IWE (AMP XI.S1). However, this program (AMP XI.SS) reviews Service Levell coatings to ensure that the protective coating monitoring and maintenance program are adequate for license renewal.
Evaluation and Technical Basis
- 1. Scope of Program: The minimum scope of the program is Service Level I coatings applied to steel and concrete surfaces inside containment (e.g., steel liner, steel containment shell, structural steel, supports, penetrations, and concrete walls and floors), defined in NRC RG 1.54, Rev. 2, as follows: "Service Level I coatings are used in areas inside the reactor containment where the coating failure could adversely affect the operation of post-accident fluid systems and thereby impair safe shutdown." The scope of the program also should include any Service Level I coatings that are credited by the licensee for preventing loss of material due to corrosion in accordance with AMP XI.S1.
- 2. Preventive Action: The program is a condition monitoring program and does not recommend any preventive actions. However, for plants that credit coatings to minimize loss of material, this program is a preventive action.
- 3. Parameters Monitored or Inspected: Regulatory Position C4 in NRC RG 1.54, Rev 1, states that "ASTM D 5163-96 provides guidelines that are acceptable to the NRC staff for December 201 0 XI S8-1 NUREG-1801, Rev. 2 OAG10001390_00727
establishing an in-service coatings monitoring program for Service Level I coating systems in operating nuclear power plants ... " ASTM 05163-96 has been superseded by ASTM 0 5163-08. ASTM 05163-08 identifies the parameters monitored or inspected to be "any visible defects, such as blistering, cracking, flaking, peeling, rusting, and physical damage."
- 4. Detection of Aging Effects: ASTM 05163-08, paragraph 6, defines the inspection frequency to be each refueling outage or during other major maintenance outages, as needed. ASTM 05163-08, paragraph 9, discusses the qualifications for inspection personnel, the inspection coordinator, and the inspection results evaluator.
ASTM 05163-08, subparagraph 10.1, discusses development of the inspection plan and the inspection methods to be used. It states that a general visual inspection shall be conducted on all readily accessible coated surfaces during a walk-through. After a walk-through, or during the general visual inspection, thorough visual inspections shall be carried out on previously designated areas and on areas noted as deficient during the walk-through.
A thorough visual inspection shall also be carried out on all coatings near sumps or screens associated with the Emergency Core Cooling System (ECCS). This subparagraph also addresses field documentation of inspection results. ASTM 05163-08, subparagraph 10.5, identifies instruments and equipment needed for inspection.
- 5. Monitoring and Trending: ASTM 05163-08 identifies monitoring and trending activities in subparagraph 7.2, which specifies a pre-inspection review of the previous two monitoring reports, and in subparagraph 11.1.2, which specifies that the inspection report should prioritize repair areas as either needing repair during the same outage or as postponed to future outages, but under surveillance in the interim period.
- 6. Acceptance Criteria: ASTM 05163-08, subparagraphs 10.2.1 through 10.2.6, 10.3, and 10.4, contains one acceptable method for the characterization, documentation, and testing of defective or deficient coating surfaces. Additional ASTM and other recognized test methods are available for use in characterizing the severity of observed defects and deficiencies. The evaluation covers blistering, cracking, flaking, peeling, delamination, and rusting. ASTM 0 5163-08, paragraph 11, addresses evaluation. It specifies that the inspection report is to be evaluated by the responsible evaluation personnel, who prepare a summary of findings and recommendations for future surveillance or repair, and prioritization of repairs.
- 7. Corrective Actions: A recommended corrective action plan is required for major defective areas so that these areas can be repaired during the same outage, if appropriate. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions.
- 8. Confirmation Process: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the confirmation process.
- 9. Administrative Controls: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the administrative controls.
- 10. Operating Experience: NRC Information Notice 88-82, NRC Bulletin 96-03, NRC Generic Letter (GL) 04-02, and NRC GL 98-04 describe industry experience pertaining to coatings degradation inside containment and the consequential clogging of sump strainers. NRC NUREG-1801, Rev. 2 XI S8-2 December 201 0 OAG10001390_00728
RG 1.54, Rev. 1, was issued in July 2000. Monitoring and maintenance of Service Level I coatings conducted in accordance with Regulatory Position C4 is expected to be an effective program for managing degradation of Service Level I coatings and, consequently, an effective means to manage loss of material due to corrosion of carbon steel structural elements inside containment.
References 10 CFR Part 50, Appendix B, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
ASTM D 5163-05, Guide for Establishing Procedures to Monitor the Performance of Coating Service Levell Coating Systems in an Operating Nuclear Power Plant, American Society for Testing and Materials, 2005.
ASTM D 5163-08, Standard Guide for Establishing a Program for Condition Assessment of Coating Service Levell Coating Systems in Nuclear Power Plants, American Society for Testing and Materials, 2008.
ASTM D 5163-96, Standard Guide for Establishing Procedures to Monitor the Performance of Safety Related Coatings in an Operating Nuclear Power Plant, American Society for Testing and Materials, 1996.
EPRI Report 1003102, Guideline on Nuclear Safety-Related Coatings, Revision 1, (Formerly TR-109937), Electric Power Research Institute, November 2001.
EPRI Report 1019157, Guideline on Nuclear Safety-Related Coatings, Revision 2, (Formerly TR-109937and 1003102), Electric Power Research Institute, December 2009.
NRC Bulletin 96-03, Potential Plugging of Emergency Core Cooling Suction Strainers by Debris in Boiling-Water Reactors, U.S. Nuclear Regulatory Commission, May 6, 1996.
NRC Generic Letter 98-04, Potential for Degradation of the Emergency Core Cooling System and the Containment Spray System After a Loss-Of-Coo/ant Accident Because of Construction and Protective Coating Deficiencies and Foreign Material in Containment, U.S. Nuclear Regulatory Commission, July 14, 1998.
NRC Generic Letter 04-02, Potential Impact of Debris Blockage on Emergency Recirculation during Design Basis Accidents at Pressurized-Water Reactors, U.S. Nuclear Regulatory Commission, September 13, 2004.
NRC Information Notice 88-82, Torus Shells with Corrosion and Degraded Coatings in BWR Containments, U.S. Nuclear Regulatory Commission, November 14, 1988.
NRC Information Notice 97-13, Deficient Conditions Associated With Protective Coatings at Nuclear Power Plants, U.S. Nuclear Regulatory Commission, March 24, 1997.
NRC Regulatory Guide 1.54, Rev. 0, Quality Assurance Requirements for Protective Coatings Applied to Water-Cooled Nuclear Power Plants, U.S. Nuclear Regulatory Commission, June 1973.
December 201 0 XI S8-3 NUREG-1801, Rev. 2 OAG10001390_00729
NRC Regulatory Guide 1.54, Rev. 1, Service Levell, II, and 11/ Protective Coatings Applied to Nuclear Power Plants, U.S. Nuclear Regulatory Commission, July 2000.
NRC Regulatory Guide 1.54, Rev. 2, Service Levell, II, and 11/ Protective Coatings Applied to Nuclear Power Plants, U.S. Nuclear Regulatory Commission, October 2010.
NUREG-1801, Rev. 2 XI S8-4 December 201 0 OAG10001390_00730
XI.E1 INSULATION MATERIAL FOR ELECTRICAL CABLES AND CONNECTIONS NOT SUBJECT TO 10 CFR 50.49 ENVIRONMENTAL QUALIFICATION REQUIREMENTS Program Description The purpose of the aging management program (AMP) described herein is to provide reasonable assurance that the intended functions of electrical cables and connections that are not subject to the environmental qualification requirements of 10 CFR 50.49 and are exposed to adverse localized environments caused by temperature, radiation, or moisture are maintained consistent with the current licensing basis through the period of extended operation.
In most areas within a nuclear power plant, the actual ambient environments (e.g., temperature, radiation, or moisture) are less severe than the plant design environment. However, in a limited number of localized areas, the actual environments may be more severe than the plant design environment.
Insulation materials used in electrical cables and connections may degrade more rapidly than expected in these adverse localized environments. An adverse localized environment is a condition in a limited plant area that is significantly more severe than the plant design environment for the cable or connection insulation material that could increase the rate of aging of a component or have an adverse effect on operability. An adverse localized environment exists based on the most limiting condition for temperature, radiation, or moisture for the insulation material of cables or connections. Adverse localized environments can be identified through the use of an integrated approach. This approach may include, but is not limited to, (a) the review of Environmental Qualification (EQ) zone maps that show radiation levels and temperatures for various plant areas, (b) consultations with plant staff who are cognizant of plant conditions, (c) utilization of infrared thermography to identify hot spots on a real-time basis, and (d) the review of relevant plant-specific and industry operating experience.
The program described herein was written specifically to address cables and connections at plants whose configuration is such that most (if not all) cables and connections installed in adverse localized environments are accessible. Cables and connections from accessible areas are inspected and represent, with reasonable assurance, all cables and connections in the adverse localized environments. If an unacceptable condition or situation is identified for a cable or connection in the inspection, a determination is made as to whether the same condition or situation is applicable to inaccessible cables or connections. As such, this program does not apply to plants in which most cables are inaccessible.
As stated in NUREG/CR-5643, "the major concern is that failures of deteriorated cable systems (cables, connections, and penetrations) might be induced during accident conditions." Since the cables and connections are not subject to the environmental qualification requirements of 10 CFR 50.49, an AMP is required to manage the aging effects. This AMP provides reasonable assurance the insulation material for electrical cables and connections will perform its intended function for the period of extended operation.
Evaluation and Technical Basis
- 1. Scope of Program: This AMP applies to accessible electrical cables and connections within the scope of license renewal that are located in adverse localized environments caused by temperature, radiation, or moisture.
December 201 0 XI E1-1 NUREG-1801, Rev. 2 OAG10001390_00731
- 2. Preventive Actions: This is a condition monitoring program and no actions are taken as part of this program to prevent or mitigate aging degradation.
- 3. Parameters Monitored/Inspected: Accessible electrical cables and connections installed in adverse localized environments are visually inspected for cable jacket and connection insulation surface anomalies indicating signs of reduced insulation resistance due to thermal/thermoxidative degradation of organics, radiolysis and photolysis (UV sensitive materials only) of organics; radiation-induced oxidation, and moisture intrusion as indicated by signs of embrittlement, discoloration, cracking, melting, swelling or surface contamination. An adverse localized environment is a plant-specific condition; therefore, the applicant should clearly define how this condition is determined. The applicant should determine and inspect the adverse localized conditions for each of the most limiting temperature, radiation, or moisture conditions for the accessible cables and connections that are within the scope of license renewal.
- 4. Detection of Aging Effects: Insulation aging degradation from temperature, radiation, or moisture causes cable jacket and connection insulation surface anomalies. Accessible electrical cables and connections installed in adverse localized environments are visually inspected for cable jacket and connection insulation surface anomalies, such as embrittlement, discoloration, cracking, melting, swelling or surface contamination. The inspection of cable jacket and connection insulation surfaces is used to infer the adequacy of the cables and connections. Accessible electrical cables and connections installed in adverse localized environments are visually inspected at least once every 10 years. This is an adequate period to preclude failures of the cables and connection insulation since experience has shown that aging degradation is a slow process. A 1O-year inspection interval provides two data points during a 20-year period, which can be used to characterize the degradation rate. The first inspection for license renewal is to be completed prior to the period of extended operation.
- 5. Monitoring and Trending: Trending actions are not included as part of this AMP, because the ability to trend visual inspection results is limited. However, inspection results that are trendable provide additional information on the rate of cable or connection degradation.
- 6. Acceptance Criteria: The accessible cables and connections are to be free from unacceptable visual indications of surface anomalies that suggest that cable jacket or connection insulation degradation exists. An unacceptable indication is defined as a noted condition or situation that, if left unmanaged, could lead to a loss of the intended function.
- 7. Corrective Actions: All unacceptable visual indications of cable jacket and connection insulation surface anomalies are subject to an engineering evaluation. Such an evaluation is to consider the age and operating environment of the component as well as the severity of the anomaly and whether such an anomaly has previously been correlated to degradation of cables or connections. Corrective actions may include, but are not limited to, testing, shielding, or otherwise changing the environment or relocation or replacement of the affected cables or connections. When an unacceptable condition or situation is identified, a determination is made as to whether the same condition or situation is applicable to inaccessible cables or connections. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the corrective actions.
NUREG-1801, Rev. 2 XI E1-2 December 201 0 OAG10001390_00732
- 8. Confirmation Process: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the confirmation process.
- 9. Administrative Controls: The administrative controls for this AMP provide for a formal review and approval process. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the administrative controls.
- 10. Operating Experience: Operating experience has shown that adverse localized environments caused by elevated temperature, radiation, or moisture for electrical cables and connections may exist. For example next to or above (within 3 feet of) steam generators, pressurizers, or hot process pipes, such as feedwater lines. These adverse localized environments have been found to cause degradation of the insulating materials on electrical cables and connections that are visually observable, such as color changes or surface cracking. These visual indications can be used as indicators of degradation.
This AMP considers the technical information and guidance provided in NUREG/CR-5643, IEEE Std. 1205-2000, SAND96-0344, and EPRI TR-109619.
References 10 CFR Part 50, Appendix 8, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
EPRI TR-109619, Guideline for the Management of Adverse Localized Equipment Environments, Electric Power Research Institute, Palo Alto, CA, June 1999.
IEEE Std. 1205-2000, IEEE Guide for Assessing, Monitoring and Mitigating Aging Effects on Class 1E Equipment Used in Nuclear Power Generating Stations.
NUREG/CR-5643, Insights Gained From Aging Research, U. S. Nuclear Regulatory Commission, March 1992.
SAND96-0344, Aging Management Guideline for Commercial Nuclear Power Plants - Electrical Cable and Terminations, prepared by Sandia National Laboratories for the U.S. Department of Energy, September 1996.
December 201 0 XI E1-3 NUREG-1801, Rev. 2 OAG10001390_00733
XI.E2 INSULATION MATERIAL FOR ELECTRICAL CABLES AND CONNECTIONS NOT SUBJECT TO 10 CFR 50.49 ENVIRONMENTAL QUALIFICATION REQUIREMENTS USED IN INSTRUMENTATION CIRCUITS Program Description The purpose of this aging management program (AMP) is to provide reasonable assurance that the intended functions of electrical cables and connections (that are not subject to the environmental qualification requirements of 10 CFR 50.49 and are used in instrumentation circuits with sensitive, high-voltage, low-level current signals exposed to adverse localized environments caused by temperature, radiation, or moisture) are maintained consistent with the current licensing basis through the period of extended operation.
In most areas within a nuclear power plant, the actual ambient environments (e.g., temperature, radiation, or moisture) are less severe than the plant design environment. However, in a limited number of localized areas, the actual environments may be more severe than the design environment.
Insulation materials used in electrical cables or connections may degrade more rapidly in adverse localized environments. An adverse localized environment is a condition in a limited plant area that is significantly more severe than the plant design environment for the cable or connection insulation material that could increase the rate of aging of a component or have an adverse effect on operability. Exposure of electrical cable and connection insulation material to adverse localized environments caused by temperature, radiation, or moisture can result in reduced insulation resistance (lR). Reduced IR causes an increase in leakage currents between conductors and from individual conductors to ground. A reduction in IR is a concern for all circuits, but especially those with sensitive, high voltage, low-level current signals, such as radiation monitoring and nuclear instrumentation circuits, because a reduced IR may contribute to signal inaccuracies.
In this AMP, either of two methods can be used to identify the existence of aging degradation. In the first method, calibration results or findings of surveillance testing programs are evaluated to identify the existence of cable and connection insulation material aging degradation. In the second method, direct testing of the cable system is performed.
This AMP applies to high-range-radiation and neutron flux monitoring instrumentation cables in addition to other cables used in high voltage, low-level current signal applications that are sensitive to reduction in IR. For these cables, AMP XI.E1 does not apply.
As stated in NUREG/CR-5643, "the major concern is that failures of deteriorated cable systems (cables, connections, and penetrations) might be induced during accident conditions." Since the instrumentation cables and connections are not subject to the environmental qualification requirements of 10 CFR 50.49, an AMP is required to manage the aging effects. This AMP provides reasonable assurance the insulation material for electrical cables and connections will perform its intended function for the period of extended operation.
Evaluation and Technical Basis
- 1. Scope of Program: This AMP applies to electrical cables and connections (cable system) used in circuits with sensitive, high voltage, low-level current signals, such as radiation December 201 0 XI E2-1 NUREG-1801, Rev. 2 OAG10001390_00734
monitoring and nuclear instrumentation, that are subject to aging management review and installed in adverse localized environments caused by temperature, radiation, or moisture.
- 2. Preventive Actions: This is a performance monitoring program and no actions are taken as part of this program to prevent or mitigate aging degradation.
- 3. Parameters Monitored/Inspected: The parameters monitored are determined from the specific calibration, surveillances, or testing performed and are based on the specific instrumentation circuit under surveillance or being calibrated, as documented in plant procedures.
- 4. Detection of Aging Effects: Review of calibration results or findings of surveillance programs can provide an indication of the existence of aging effects based on acceptance criteria related to instrumentation circuit performance. By reviewing the results obtained during normal calibration or surveillance, an applicant may detect severe aging degradation prior to the loss of the cable and connection intended function. The first reviews are completed prior to the period of extended operation and at least every 10 years thereafter.
All calibration or surveillance results that do not meet acceptance criteria are reviewed for aging effects when the results are available.
Cable system testing is conducted when the calibration or surveillance program does not include the cabling system in the testing circuit, or as an alternative to the review of calibration results described above. A proven cable system test for detecting deterioration of the insulation system (such as insulation resistance tests, time domain reflectometry tests, or other testing judged to be effective in determining cable system insulation condition as justified in the application) is performed. The test frequency of the cable system is determined by the applicant based on engineering evaluation, but the test frequency is at least once every 10 years. The first test is to be completed prior to the period of extended operation.
- 5. Monitoring and Trending: Trending actions are not included as part of this AMP because the ability to trend test results is dependent on the specific type of test chosen. However, test results that are trendable provide additional information on the rate of cable or connection degradation.
- 6. Acceptance Criteria: Calibration results or findings of surveillance and cable system testing are to be within the acceptance criteria, as set out in the applicant's procedures.
- 7. Corrective Actions: Corrective actions, such as recalibration and circuit trouble-shooting, are implemented when calibration, surveillance, or cable system test results do not meet the acceptance criteria. An engineering evaluation is performed when the acceptance criteria are not met in order to ensure that the intended functions of the electrical cable system can be maintained consistent with the current licensing basis. Such an evaluation is to consider the significance of the calibration, surveillance, or cable system test results; the operability of the component; the reportability of the event; the extent of the concern; the potential root causes for not meeting the acceptance criteria; the corrective actions required; and likelihood of recurrence. When an unacceptable condition or situation is identified, a determination also is made as to whether the review of calibration and surveillance results or the cable system testing frequency needs to be increased. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions.
NUREG-1801, Rev. 2 XI E2-2 December 201 0 OAG10001390_00735
- 8. Confirmation Process: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address confirmation process.
- 9. Administrative Controls: The administrative controls for this AMP provide for a formal review and approval process. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the administrative controls.
- 10. Operating Experience: Operating experience has identified a case where a change in temperature across a high range radiation monitor cable in containment resulted in a substantial change in the reading of the monitor. Changes in instrument calibration can be caused by degradation of the circuit cable and are a possible indication of electrical cable degradation.
The vast majority of site-specific and industry wide operating experience regarding neutron flux instrumentation circuits is related to cable/connector issues inside containment near the reactor vessel.
This AMP considers the technical information and guidance provided in NUREG/CR-5643, IEEE Std. 1205-2000, SAND96-0344, EPRI TR-109619, NRC IN 97-45, and NRC IN 97-45, Supplement 1.
References 10 CFR Part 50, Appendix 8, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
EPRI TR-109619, Guideline for the Management of Adverse Localized Equipment Environments, Electric Power Research Institute, Palo Alto, CA, June 1999.
IEEE Std. 1205-2000, IEEE Guide for Assessing, Monitoring and Mitigating Aging Effects on Class 1E Equipment Used in Nuclear Power Generating Stations.
NRC Information Notice 97-45, Environmental Qualification Deficiency for Cables and Containment Penetration Pigtails, U. S, Nuclear Regulatory Commission, July 2, 1997.
NRC Information Notice 97-45, Supplement 1, Environmental Qualification Deficiency for Cables and Containment Penetration Pigtails, U. S, Nuclear Regulatory Commission, February 17, 1998.
NUREG/CR-5643, Insights Gained From Aging Research, U. S. Nuclear Regulatory Commission, March 1992.
SAND96-0344, Aging Management Guideline for Commercial Nuclear Power Plants - Electrical Cable and Terminations, prepared by Sandia National Laboratories for the U.S. Department of Energy, September 1996.
December 201 0 XI E2-3 NUREG-1801, Rev. 2 OAG10001390_00736
XI.E3 INACCESSIBLE POWER CABLES NOT SUBJECT TO 10 CFR 50.49 ENVIRONMENTAL QUALIFICATION REQUIREMENTS Program Description The purpose of the aging management program (AMP) described herein is to provide reasonable assurance that the intended functions of inaccessible or underground power cables that are not subject to the environmental qualification requirements of 10 CFR 50.49 and are exposed to wetting or submergence are maintained consistent with the current licensing basis through the period of extended operation.
Most electrical cables in nuclear power plants are located in dry environments. However, some cables may be exposed to wetting or submergence, and are inaccessible or underground, such as cables in conduits, cable trenches, cable troughs, duct banks, underground vaults, or directly buried in soil installations. When a power cable (greater than or equal to 400 volts) is exposed to wet, submerged, or other adverse environmental conditions for which it was not designed, an aging effect of reduced insulation resistance may result, causing a decrease in the dielectric strength of the conductor insulation. This insulation degradation can be caused by wetting or submergence. This can potentially lead to failure of the cable's insulation system.
In this AMP, periodic actions are taken to prevent cables from being exposed to significant moisture, defined as periodic exposures to moisture that last more than a few days (e.g., cable wetting or submergence in water. Examples of periodic actions are inspecting for water collection in cable manholes and conduits and draining water, as needed. However, the above actions are not sufficient to ensure that water is not trapped elsewhere in the raceways. For example, (a) if a duct bank conduit has low points in the routing, there could be potential for long-term submergence at these low points; (b) concrete raceways may crack due to soil settling over a long period of time; (c) manhole covers may not be watertight; (d) in certain areas, the water table is high in seasonal cycles, so the raceways may get refilled soon after purging; and (e) potential uncertainties exist with water trees even when duct banks are sloped with the intention to minimize water accumulation.
Experience has shown that insulation degradation may occur if the cables are exposed to 100 percent relative humidity. The above periodic actions are necessary to minimize the potential for insulation degradation. In addition to above periodic actions, in-scope power cables exposed to significant moisture are tested to indicate the condition of the conductor insulation. The specific type of test performed is determined prior to the initial test, and is to be a proven test for detecting deterioration of the insulation system due to wetting or submergence, such as Dielectric Loss (Dissipation Factor/Power Factor), AC Voltage Withstand, Partial Discharge, Step Voltage, Time Domain Reflectometry, Insulation Resistance and Polarization Index, Line Resonance Analysis, or other testing that is state-of-the-art at the time the tests are performed.
One or more tests are used to determine the condition of the cables so they will continue to meet their intended function during the period of extended operation.
As stated in NUREG/CR-5643, "the major concern is that failures of deteriorated cable systems (cables, connections, and penetrations) might be induced during accident conditions." Because the cables are not subject to the environmental qualification requirements of 10 CFR 50.49, an AMP is required to manage the aging effects. This AMP provides reasonable assurance the insulation material for electrical cables will perform its intended function for the period of extended operation.
December 201 0 XI E3-1 NUREG-1801, Rev. 2 OAG10001390_00737
Evaluation and Technical Basis
- 1. Scope of Program: This AMP applies to all inaccessible or underground (e.g., in conduit, duct bank, or direct buried) power cables (greater than or equal to 400 volts) within the scope of license renewal exposed to adverse environments, primarily significant moisture.
Significant moisture is defined as periodic exposures to moisture that last more than a few days (e.g., cable wetting or submergence in water). Submarine or other cables designed for continuous wetting or submergence are not included in this AMP.
- 2. Preventive Actions: This is a condition monitoring program. However, periodic actions are taken to prevent inaccessible cables from being exposed to significant moisture, such as identifying and inspecting in-scope accessible cable conduit ends and cable manholes for water collection, and draining the water, as needed.
The inspection frequency for water collection is established and performed based on plant-specific operating experience with cable wetting or submergence in manholes (i.e., the inspection is performed periodically based on water accumulation over time and event driven occurrences, such as heavy rain or flooding). The periodic inspection should occur at least annually. The inspection should include direct observation that cables are not wetted or submerged, that cables/splices and cable support structures are intact, and that dewatering/drainage systems (i.e., sump pumps) and associated alarms operate properly. In addition, operation of dewatering devices should be inspected and operation verified prior to any known or predicted heavy rain or flooding events. If water is found during inspection (i.e., cable exposed to significant moisture), corrective actions are taken to keep the cable dry and to assess cable degradation. The first inspection for license renewal is completed prior to the period of extended operation.
- 3. Parameters Monitored/Inspected: Inspection for water collection is performed based on plant-specific operating experience with water accumulation in the manhole. Inaccessible or underground power (greater than or equal to 400 volts) cables within the scope of license renewal exposed to significant moisture are tested to provide an indication of the condition of the conductor insulation. The specific type of test to be used should be capable of detecting reduced insulation resistance of the cable's insulation system due to wetting or submergence.
- 4. Detection of Aging Effects: For power cables exposed to significant moisture, test frequencies are adjusted based on test results (including trending of degradation where applicable) and operating experience. Cable testing should occur at least once every 6 years. A 6-year interval provides multiple data points during a 20-year period, which can be used to characterize the degradation rate. This is an adequate period to monitor performance of the cable and take appropriate corrective actions since experience has shown that although a slow process, aging degradation could be significant.. The first tests for license renewal are to be completed prior to the period of extended operation with subsequent tests performed at least every 6 years thereafter. The applicant can assess the condition of the cable insulation with reasonable confidence using one or more of the following techniques: Dielectric Loss (Dissipation Factor/Power Factor), AC Voltage Withstand, Partial Discharge, Step Voltage, Time Domain Reflectometry, Insulation Resistance and Polarization Index, Line Resonance Analysis, or other testing that is state-of-the-art at the time the tests are performed. One or more tests are used to determine the condition of the cables so they will continue to meet their intended function during the period of extended operation.
NUREG-1801, Rev. 2 XI E3-2 December 201 0 OAG10001390_00738
- 5. Monitoring and Trending: Trending actions are included as part of this AMP, although the ability to trend results is dependent on the specific type of test(s) or inspection chosen.
Results that are trendable provide additional information on the rate of cable insulation degradation.
- 6. Acceptance Criteria: The acceptance criteria for each test are defined by the specific type of test performed and the specific cable tested. Acceptance criteria for inspections of manholes are defined by the observation that the cables and support structures are not submerged or immersed in standing water at the time of the inspection.
- 7. Corrective Actions: Corrective actions are taken and an engineering evaluation is performed when the test or inspection acceptance criteria are not met. Such an evaluation considers the significance of the test or inspection results, the operability of the component, the reportability of the event, the extent of the concern, the potential root causes for not meeting the test or inspection acceptance criteria, the corrective actions required, and the likelihood of recurrence. When an unacceptable condition or situation is identified, a determination is made as to whether the same condition or situation is applicable to other accessible or inaccessible, in-scope power cables. Corrective actions may include, but are not limited to, installation of permanent drainage systems, installation of sump pumps and alarms, more frequent cable testing or manhole inspections, or replacement of the affected cable. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions.
- 8. Confirmation Process: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the confirmation process.
- 9. Administrative Controls: The administrative controls for this AMP provide for a formal review and approval process. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the administrative controls.
- 10. Operating Experience: Operating experience has shown that insulation materials are susceptible to water tree formation. The formation and growth of water trees varies directly with operating voltage. Aging effects of reduced insulation resistance due to other mechanisms may also result in a decrease in the dielectric strength of the conductor insulation. Minimizing exposure to moisture mitigates the potential for the development of reduced insulation resistance.
Recent incidents involving early failures of electric cables and cable failures leading to multiple equipment failures, are cited in NRC IN 2002-12, "Submerged Safety-Related Cables," and NRC GL 2007-01, "Inaccessible or Underground Power Cable Failures That Disable Accident Mitigation Systems or Cause Plant Transients."
The NRC issued GL 2007-001 on inaccessible or underground cables to (a) inform licensees that the failure of certain power cables can affect the functionality of multiple accident mitigation systems or cause plant transients and (b) gather information from licensees on the monitoring of inaccessible or underground power cable failures for all cables that are within the scope of the Maintenance Rule. Based on the review of licensees' responses, the NRC staff has identified 269 cable failures for 104 reactor units. The data obtained from the GL responses show an increasing trend of cable failures. The NRC staff December 201 0 XI E3-3 NUREG-1801, Rev. 2 OAG10001390_00739
has noted that the predominant factor contributing to cable failures at nuclear power plants was due to moisture/submergence. The staff also noted that the GL failure data show that the majority of the reported failures occurred at the 4160-volt, 480 volt, and 600-volt service voltage levels for both energized and de-energized cables. These cables are failing within the plants' 40-year licensing period.
The NRC inspectors also have continued to identify safety-related cables which are submerged. The staff noted that licensees had not demonstrated that the subject safety-related cables were designed for wetted or submerged service for the current license period.
This AMP considers the technical information and generic communication guidance provided in NUREG/CR-5643; IEEE Std. 1205-2000; SAN 096-0344; EPRI 109619; EPRI 103834-P1-2; NRC IN 2002-12; NRC GL 2007-01; NRC GL 2007-01 Summary Report; NRC Inspection Procedure, Attachment 71111.06, Flood Protection Measures; NRC Inspection Procedure, Attachment 71111.01, Adverse Weather Protection; RG 1.211 Rev 0; OG-1240; and NUREG/CR-7000.
References 10 CFR Part 50, Appendix 8, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
OG-1240, Condition Monitoring Program for Electric Cables Used In Nuclear Power Plants, June 2010.
EPRI TR-103834-P1-2, Effects of Moisture on the Life of Power Plant Cables, Electric Power Research Institute, Palo Alto, CA, August 1994.
EPRI TR-109619, Guideline for the Management of Adverse Localized Equipment Environments, Electric Power Research Institute, Palo Alto, CA, June 1999.
IEEE Std. 1205-2000, IEEE Guide for Assessing, Monitoring and Mitigating Aging Effects on Class 1E Equipment Used in Nuclear Power Generating Stations.
NRC Inspection Procedure, Attachment 71111.06, Flood Protection Measures, June 25, 2009.
NRC Inspection Procedure, Attachment 71111.01, Adverse Weather Protection, April 8, 2009.
NRC Information Notice 2002-12, Submerged Safety-Related Electrical Cables, March 21, 2002.
NRC Generic Letter 2007-01, Summary Report, Inaccessible or Underground Power Cable Failures that Disable Accident Mitigation Systems or Cause Plant Transients, November 12, 2008.
NUREG/CR-5643, Insights Gained From Aging Research, U. S. Nuclear Regulatory Commission, March 1992.
SAN 096-0344, Aging Management Guideline for Commercial Nuclear Power Plants - Electrical Cable and Terminations, prepared by Sandia National Laboratories for the U.S. Department of Energy, September 1996.
NUREG-1801, Rev. 2 XI E3-4 December 201 0 OAG10001390_00740
RG 1.211 Rev 0, Qualification of Safety-Related Cables and Field Splices for Nuclear Power Plants, April 2009.
NUREG/CR-7000, Essential Elements of an Electric Cable Condition Monitoring Program, January 2010.
December 201 0 XI E3-S NUREG-1801, Rev. 2 OAG10001390_00741
XI.E4 METAL ENCLOSED BUS Program Description The purpose of this aging management program (AMP) is to provide an internal and external inspection of Metal Enclosed Buses (MEBs) to identify age-related degradation of insulating material (i.e., porcelain, xenoy, thermoplastic organic polymers), and metallic and elastomer components (e.g., gaskets, boots, and sealants).
MEBs are electrical buses installed on electrically insulated supports that are constructed with each phase conductor enclosed in a separate metal enclosure (isolated phase bus), all conductors enclosed in a common metal enclosure (non-segregated bus), or all phase conductors in a common metal enclosure, but separated by metal barriers between phases (segregated bus). The conductors are adequately separated and insulated from ground by insulating supports or bus insulation. The MEBs are used in power systems to connect various elements in electric power circuits, such as switchgear, transformers, main generators, and diesel generators.
Industry operating experience indicates that failures of MEBs have been caused by cracked insulation and moisture, debris, or excessive dust buildup internal to the bus duct housing.
Cracked insulation has resulted from high ambient temperature and contamination from bus bar joint compounds. Cracked insulation in the presence of moisture or debris has provided phase-to-phase or phase-to-ground electrical tracking paths, which has resulted in catastrophic failure of the buses. Bus failure has led to loss of power to electrical loads connected to the buses, causing subsequent reactor trips and initiating unnecessary challenges to plant systems and operators.
MEBs may experience increased resistance of connection due to loosening of bolted bus duct connections caused by repeated thermal cycling of connected loads. This phenomenon can occur in heavily loaded circuits (i.e., those exposed to appreciable ohmic heating). For example, SAND 96-0344 identified instances of termination loosening at several plants due to thermal cycling and NRC IN 2000-14 identified torque relaxation of splice plate connecting bolts as one potential cause of a MEB fault.
This AMP includes the inspection of all bus ducts within the scope of license renewal and a sample of accessible MEB bolted connections for increased resistance of connection. The technical basis for the sample selections should be documented. If an unacceptable condition or situation is identified in the selected sample, a determination is made as to whether the same condition or situation is applicable to other connections not tested.
Evaluation and Technical Basis
- 1. Scope of Program: This AMP manages the age-related degradation effects for electrical bus bar bolted connections, bus bar insulation, bus bar insulating supports, bus enclosure assemblies (internal and external), and elastomers. This program does not manage the aging effects on external bus structural supports, which are managed under AMP XI.S6, "Structures Monitoring." Alternatively, the aging effects on elastomers can be managed under AMP XI.M38, "Inspection of Internal Surfaces in Miscellaneous Piping and Ducting Components," and the external surfaces of MEB enclosure assemblies can be managed under AMP XI.S6, "Structures Monitoring."
December 201 0 XI E4-1 NUREG-1801, Rev. 2 OAG10001390_00742
- 2. Preventive Actions: This is a condition monitoring program and no actions are taken as part of this program to prevent or mitigate aging degradation.
- 3. Parameters Monitored/Inspected: This AMP provides for the inspection of the internal and external portions of the MEB. Internal portions (bus enclosure assemblies) of the MEB are inspected for cracks, corrosion, foreign debris, excessive dust buildup, and evidence of water intrusion. The bus insulation is inspected for signs of reduced insulation resistance due to thermal/thermoxidative degradation of organics/thermoplastics, radiation-induced oxidation, moisture/debris intrusion, or ohmic heating, as indicated by embrittlement, cracking, chipping, melting, discoloration, or swelling, which may indicate overheating or aging degradation. The internal bus insulating supports are inspected for structural integrity and signs of cracks. A sample of accessible bolted connections is inspected for increased resistance of connection. Alternatively, for accessible bolted connections covered with heat shrink tape, sleeving, insulating boots, etc., the sample may be visually inspected for insulation material surface anomalies. The external portions of the MEB, including accessible gaskets, boots, and sealants, are inspected for hardening and loss of strength due to elastomer degradation that could permit water or foreign debris to enter the bus. MEB external surfaces are inspected for loss of material due to general, pitting, and crevice corrosion.
- 4. Detection of Aging Effects: MEB internal surfaces are visually inspected for aging degradation including cracks, corrosion, foreign debris, excessive dust buildup, and evidence of moisture intrusion. MEB insulating material is visually inspected for signs of embrittlement, cracking, chipping, melting, discoloration, swelling, or surface contamination.
Internal bus insulating supports are visually inspected for structural integrity and signs of cracks. MEB external surfaces are visually inspected for loss of material due to general, pitting, and crevice corrosion. Accessible elastomers (e.g., gaskets, boots, and sealants) are inspected for degradation including surface cracking, crazing, scuffing, dimensional change (e.g. "ballooning" and "necking"), shrinkage, discoloration, hardening and loss of strength.
A sample of accessible bolted connections is inspected for increased resistance of connection by using thermography or by measuring connection resistance using a micro-ohmmeter. Twenty percent of the population with a maximum sample of 25 constitutes a representative sample size. Otherwise, a technical justification of the methodology and sample size used for selecting components should be included as part of the AMP's site documentation. If an unacceptable condition or situation is identified in the selected sample, a determination is made as to whether the same condition or situation is applicable to other connections not tested.
The first inspection using thermography or measuring connection resistance is completed prior to the period of extended operation and every 10 years thereafter provided visual inspection is not used to inspect bolted connections. This is an adequate period to preclude failures of the MEBs since experience has shown that MEB aging degradation is a slow process.
As an alternative to thermography or measuring connection resistance of bolted connections, for accessible bolted connections that are covered with heat shrink tape, sleeving, insulating boots, etc., the applicant may use visual inspection of insulation material to detect surface anomalies, such as embrittlement, cracking, chipping, melting, discoloration, swelling, or surface contamination. When this alternative visual inspection is NUREG-1801, Rev. 2 XI E4-2 December 201 0 OAGI0001390_00743
used to check the bolted connection sample, the first inspection is completed prior to the period of extended operation and every 5 years thereafter.
- 5. Monitoring and Trending: Trending actions are not included as part of this AMP because the ability to trend inspection results is limited. However, results that are trendable provide additional information on the rate of degradation.
- 6. Acceptance Criteria: MEB insulation materials are free from regional indications of surface anomalies such as embrittlement, cracking, chipping, melting, discoloration, and swelling, or surface contamination. MEB internal surfaces show no indications of corrosion, cracks, foreign debris, excessive dust buildup, or evidence of moisture intrusion. Accessible elastomers (e.g., gaskets, boots, and sealants) show no indications of surface cracking, crazing, scuffing, dimensional change (e.g. "ballooning" and "necking"), shrinkage, discoloration, hardening, and loss of strength. MEB external surfaces are free from loss of material due to general, pitting, and crevice corrosion.
Bolted connections need to be below the maximum allowed temperature for the application when thermography is used or a low resistance value appropriate for the application when resistance measurement is used. When the visual inspection alternative for bolted connections is used, the absence of embrittlement, cracking, chipping, melting, discoloration, swelling, or surface contamination of the insulation material provides positive indication that the bolted connections are not loose.
- 7. Corrective Actions: Corrective actions are taken and an engineering evaluation is performed when the acceptance criteria are not met. Corrective actions may include, but are not limited, to cleaning, drying, increased inspection frequency, replacement, or repair of the affected MEB components. If an unacceptable condition or situation is identified, a determination is made as to whether the same condition or situation is applicable to other accessible or inaccessible MEBs. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the corrective actions.
- 8. Confirmation Process: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the confirmation process.
- 9. Administrative Controls: The administrative controls for this AMP provide for a formal review and approval process. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix B, acceptable to address the administrative controls.
- 10. Operating Experience: Industry experience has shown that failures have occurred on MEBs caused by cracked insulation and moisture or debris buildup internal to the MEB.
Experience also has shown that bus connections in the MEBs exposed to appreciable ohmic heating during operation may experience loosening due to repeated cycling of connected loads.
This AMP considers the technical information and guidance provided in SAND 96-0344, IEEE Std. 1205-2000, NRC IN 89-64, NRC IN 98-36, NRC IN 2000-14, and NRC IN 2007-01.
December 201 0 XI E4-3 NUREG-1801, Rev. 2 OAG10001390_00744
References 10 CFR Part 50, Appendix 8, Quality Assurance criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
IEEE Std. 1205-2000, IEEE Guide for Assessing, Monitoring and Mitigating Aging Effects on Class 1E Equipment Used in Nuclear Power Generating Stations.
NRC Information Notice 89-64, Electrical Bus Bar Failures, September 7, 1989.
NRC Information Notice 98-36, Inadequate or Poorly Controlled, Non-Safety-Re/ated Maintenance Activities Unnecessary Challenged Safety Systems, September 18, 1998.
NRC Information Notice 2000-14, Non-Vital Bus Fault Leads to Fire and Loss of Offsite Power, September 27,2000.
NRC Information Notice 2007-01, Recent Operating Experience Concerning Hydrostatic Barriers, January 31, 2007.
SAND 96-0344, Aging Management Guideline for Commercial Nuclear Power Plants-Electrical Cable and Terminations, prepared by Sandia National Laboratories for the U.S.
Department of Energy, September 1996.
NUREG-1801, Rev. 2 XI E4-4 December 201 0 OAG10001390_00745
XI.E5 FUSE HOLDERS Program Description The purpose of the aging management program (AMP) described herein is to provide reasonable assurance that the intended functions of the metallic clamps of fuse holders are maintained consistent with the current licensing basis through the period of extended operation.
Fuse holders (fuse blocks) are classified as a specialized type of terminal block because of the similarity in fuse holder design and construction to that of a terminal block. Fuse holders are typically constructed of blocks of rigid insulating material, such as phenolic resins. Metallic clamps (clips) are attached to the blocks to hold each end of the fuse. The clamps, which are typically made of copper, can be spring-loaded clips that allow the fuse ferrules or blades to slip in, or they can be bolt lugs, to which the fuse ends are bolted.
AMP XI.E1, "Insulation for Electrical Cables and Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements," manages the aging of insulating material but not the metallic clamps of the fuse holders. The AMP for fuse holders (metallic clamps) needs to account for the following aging stressors if applicable: increased resistance of connection due to chemical contamination, corrosion, and oxidation or fatigue caused by ohmic heating, thermal cycling, electrical transients, frequent manipulation, or vibration. AMP XI.E1 is based on only a visual inspection of accessible cables and connections. Visual inspection is not sufficient to detect the aging effects from chemical contamination, corrosion, oxidation, fatigue, or vibration on the metallic clamps of the fuse holder.
Fuse holders that are within the scope of license renewal should be tested to provide an indication of the condition of the metallic clamps of the fuse holders. The specific type of test performed is determined prior to the initial test and is to be a proven test for detecting deterioration of metallic clamps of the fuse holders, such as thermography, contact resistance testing, or other appropriate testing justified in the application.
As stated in NUREG-1760, "Aging Assessment of Safety-Related Fuses Used in Low and Medium-Voltage Applications in Nuclear Power Plants," fuse holders experience a number of age-related failures. The major concern is that failures of a deteriorated cable system (cables, connections including fuse holders, and penetrations) might be induced during accident conditions. Since they are not subject to the environmental qualification requirements of 10 CFR 50.49, an AMP is required to manage the aging effects. This AMP ensures that fuse holders will perform their intended function for the period of extended operation.
Evaluation and Technical Basis
- 1. Scope of Program: This AMP manages fuse holders (metallic clamps) located outside of active devices that are considered susceptible to the following aging effects: increased resistance of connection due to chemical contamination, corrosion, and oxidation or fatigue caused by ohmic heating, thermal cycling, electrical transients, frequent manipulation, or vibration. Fuse holders inside an active device (e.g., switchgear, power supplies, power inverters, battery chargers, and circuit boards) are not within the scope of this AMP.
- 2. Preventive Actions: This is a condition monitoring program and no actions are taken as part of this program to prevent or mitigate aging degradation.
December 201 0 XI ES-1 NUREG-1801, Rev. 2 OAG10001390_00746
- 3. Parameters Monitored/Inspected: The metallic clamp portion of the fuse holder is tested to provide an indication of increased resistance of the connection due to chemical contamination, corrosion, and oxidation or fatigue caused by ohmic heating, thermal cycling, electrical transients, frequent manipulation or vibration.
- 4. Detection of Aging Effects: Fuse holders within the scope of license renewal are tested at least once every 10 years to provide an indication of the condition of the metallic clamp of the fuse holder. Testing may include thermography, contact resistance testing, or other appropriate testing methods. This is an adequate period to preclude failures of the fuse holders since experience has shown that aging degradation is a slow process. A 10-year testing interval provides two data points during a 20-year period, which can be used to characterize the degradation rate. The first tests for license renewal are to be completed prior to the period of extended operation.
- 5. Monitoring and Trending: Trending actions are not included as part of this AMP because the ability to trend test results is dependent on the specific type of test chosen. However, results that are trendable provide additional information on the rate of degradation.
- 6. Acceptance Criteria: The acceptance criteria for each test are defined by the specific type of test performed and the specific type of fuse holder tested. The metallic clamp of the fuse holder needs to be below the maximum allowed temperature for the application when thermography is used; otherwise, a low resistance value appropriate for the application when resistance measurement is used.
- 7. Corrective Action: Corrective actions are taken and an engineering evaluation is performed when the test acceptance criteria are not met in order to ensure that the intended functions of the fuse holders can be maintained consistent with the current licensing basis.
Such an evaluation is to consider the significance of the test results, the operability of the component, the reportability of the event, the extent of the concern, the potential root causes for not meeting the test acceptance criteria, the corrective action necessary, and the likelihood of recurrence. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the corrective actions.
- 8. Confirmation Process: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the confirmation process.
- 9. Administrative Controls: The administrative controls for this AMP provide for a formal review and approval process. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the administrative controls.
- 10. Operating Experience: Operating experience has shown that loosening of fuse holders and corrosion of fuse clips are aging mechanisms that, if left unmanaged, can lead to a loss of electrical continuity function. Operating experience in NUREG-1760 documented fuse holder failures due to fatigue and recommends maintenance procedures be reviewed to minimize removal and reinsertion of fuses to de-energize components (as this can lead to degradation of the fuse holders).
This AMP considers the technical information and guidance provided in NUREG-1760, IEEE Std. 1205-2000, NRC IN 86-87, NRC IN 87-42, and NRC IN 91-78.
NUREG-1801, Rev. 2 XI ES-2 December 201 0 OAG10001390_00747
References 10 CFR Part 50, Appendix 8, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
IEEE standard 1205-2000, IEEE Guide for Assessing, Monitoring, and Mitigating Aging Effects on Class 1E Equipment Used in Nuclear Power Generating Stations.
NRC Information Notice 86-87, Loss of Offsite Power Upon an Automatic Bus Transfer, October 10, 1986.
NRC Information Notice 87-42, Diesel Generator Fuse Contacts, September 4, 1987.
NRC Information Notice 91-78, Status Indication of Control Power for Circuit Breakers Used in Safety-Related Application, November 28, 1991.
NUREG-1760, Aging Assessment of Safety-Related Fuses Used in Low- and Medium-Voltage Applications in Nuclear Power Plants, May 31, 2002.
December 201 0 XI ES-3 NUREG-1801, Rev. 2 OAG10001390_00748
XI.E6 ELECTRICAL CABLE CONNECTIONS NOT SUBJECT TO 10 CFR 50.49 ENVIRONMENTAL QUALIFICATION REQUIREMENTS Program Description The purpose of the aging management program (AMP) described herein is to provide reasonable assurance that the intended functions of the metallic parts of electrical cable connections that are not subject to the environmental qualification requirements of 10 CFR 50.49 and susceptible to age-related degradation resulting in increased resistance of connection due to thermal cycling, ohmic heating, electrical transients, vibration, chemical contamination, corrosion, or oxidation are maintained consistent with the current licensing basis through the period of extended operation.
Cable connections are used to connect cable conductors to other cable conductors or electrical devices. Connections associated with cables within the scope of license renewal are part of this AMP. The most common types of connections used in nuclear power plants are splices (butt or bolted), crimp-type ring lugs, connectors, and terminal blocks. Most connections involve insulating material and metallic parts. This AMP focuses on the metallic parts of the electrical cable connections. This AMP provides a one-time test, on a sampling basis, to ensure that either aging of metallic cable connections is not occurring and/or that the existing preventive maintenance program is effective such that a periodic inspection program is not required. The one-time test confirms the absence of age-related degradation of cable connections resulting in increased resistance of connection due to thermal cycling, ohmic heating, electrical transients, vibration, chemical contamination, corrosion, or oxidation.
AM P XI. E 1, "I nsulation Material for Electrical Cables and Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements," manages the aging of insulating material but not the metallic parts of the electrical connections. AMP XI.E1 is based on a visual inspection of accessible cables and connections. Visual inspection may not be sufficient to detect the aging effects from thermal cycling, ohmic heating, electrical transients, vibration, chemical contamination, corrosion, or oxidation on the metallic parts of cable connections.
Electrical cable connections exposed to appreciable ohmic or ambient heating during operation may experience increased resistance of connection caused by repeated cycling of connected loads or of the ambient temperature environment. Different materials used in various cable system components can produce situations where stresses between these components change with repeated thermal cycling. For example, under loaded conditions, ohmic heating may raise the temperature of a compression terminal and cable conductor well above the ambient temperature, thereby causing thermal expansion of both components. Thermal expansion coefficients of different materials may alter mechanical stresses between the components and may adversely impact the termination. When the current is reduced, the affected components cool and contract. Repeated cycling in this fashion can cause loosening of the termination and may lead to increased resistance of connection or eventual separation of compression-type terminations. Threaded connectors may loosen if subjected to significant thermally-induced stress and cycling.
Cable connections within the scope of license renewal should be tested at least once prior to the period of extended operation to provide an indication of the integrity of the cable connections. The specific type of test to be performed is a proven test for detecting increased resistance of connection, such as thermography, contact resistance testing, or another appropriate test. As an alternative to thermography or resistance measurement of cable December 2010 XI E6-1 NUREG-1801, Rev. 2 OAG10001390_00749
connections, for the accessible cable connections that are covered with insulation materials such as tape, the applicant may perform visual inspection of insulation material to detect aging effects for covered cable connections. When this alternative visual inspection is used to check cable connections, the applicant must use periodic inspections and cannot use a one-time test to confirm the absence of age-related degradation of cable connections. The basis for performing only a periodic visual inspection is documented.
This AMP, as described, is a sampling program. The following factors are considered for sampling: voltage level (medium and low voltage), circuit loading (high loading), connection type and location (high temperature, high humidity, vibration, etc.). The technical basis for the sample selections should be documented. If an unacceptable condition or situation is identified in the selected sample, a determination is made as to whether the same condition or situation is applicable to other connections not tested. The corrective action program is used to evaluate the condition and determine appropriate corrective action.
SAN 096-0344, "Aging Management Guidelines for Electrical Cable and Terminations,"
indicated that loose terminations were identified by several plants. The major concern is failures of a deteriorated cable system (cables, connections including fuse holders, and penetrations) that could prevent it from performing its intended function. This AMP is not applicable to cable connections in harsh environments since they are already addressed by the requirements of 10 CFR 50.49. Even though cable connections may not be exposed to harsh environments, increased resistance of connection is a concern due to the aging mechanisms discussed above.
Evaluation and Technical Basis
- 1. Scope of Program: Cable connections associated with cables within the scope of license renewal that are external connections terminating at active or passive devices, are in the scope of this AMP. Wiring connections internal to an active assembly are considered part of the active assembly and, therefore, are not within the scope of this AMP. This AMP does not include high-voltage (>35 kilovolts) switchyard connections. The cable connections covered under the Environmental Qualification (EQ) program are not included in the scope of this program.
- 2. Preventive Actions: This is a condition monitoring program, and no actions are taken as part of this program to prevent or mitigate aging degradation.
- 3. Parameters Monitored/Inspected: This AMP focuses on the metallic parts of the connection. The one-time testing verifies that increased resistance of connection due to thermal cycling, ohmic heating, electrical transients, vibration, chemical contamination, corrosion, or oxidation is not an aging effect that requires periodic testing. A representative sample of electrical cable connections is tested. The following factors are considered for sampling: voltage level (medium and low voltage), circuit loading (high load), connection type, and location (high temperature, high humidity, vibration, etc.). The technical basis for the sample selection is documented.
- 4. Detection of Aging Effects: A representative sample of electrical connections within the scope of license renewal is tested at least once prior to the period of extended operation to confirm that there are no aging effects requiring management during the period of extended operation. Testing may include thermography, contact resistance testing, or other appropriate testing methods without removing the connection insulation, such as heat shrink tape, sleeving, insulating boots, etc. The one-time test provides additional confirmation to NUREG-1801, Rev. 2 XI E6-2 December 201 0 OAG10001390_00750
support industry operating experience that shows that electrical connections have not experienced a high degree of failures, and that existing installation and maintenance practices are effective. Twenty percent of the population with a maximum sample of 25 constitutes a representative sample size. Otherwise a technical justification of the methodology and sample size used for selecting components for one-time test should be included as part of the AMP's site documentation.
As an alternative to thermography or measuring connection resistance of the cable connection sample, for accessible cable connections that are covered with heat shrink tape, sleeving, insulating boots, etc., the applicant may use visual inspection of insulation materials to detect surface anomalies, such as embrittlement, cracking, chipping, melting, discoloration, swelling or surface contamination. When this alternative visual inspection is used to check cable connections, the first inspection is completed prior to the period of extended operation and every 5 years thereafter. The basis for performing only a periodic visual inspection to monitor age-related degradation of cable connections is documented.
- 5. Monitoring and Trending: Trending actions are not included as part of this AMP because it is a one-time testing or, alternatively, a periodic visual inspection program where the ability to trend inspection results is limited. However, results that are trendable provide additional information on the rate of degradation.
- 6. Acceptance Criteria: Cable connections should not indicate abnormal temperature for the application when thermography is used; otherwise a low resistance value appropriate for the application when resistance measurement is used. When the visual inspection alternative for covered cable connections is used, the absence of embrittlement, cracking, chipping, melting, discoloration, swelling or surface contamination indicates that the covered cable connection components are not loose.
- 7. Corrective Actions: If acceptance criteria are not met, the corrective action program is used to perform an evaluation that considers the extent of the condition, the indications of aging effect, and changes to the one-time testing program or alternative inspection program.
Corrective actions may include, but are not limited to, sample expansion, increased inspection frequency, and replacement or repair of the affected cable connection components. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the corrective actions.
- 8. Confirmation Process: As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the confirmation process.
- 9. Administrative Controls: The administrative controls for this AMP provide for a formal review and approval process. As discussed in the Appendix for GALL, the staff finds the requirements of 10 CFR Part 50, Appendix 8, acceptable to address the administrative controls.
- 10. Operating Experience: Electrical cable connections exposed to thermal cycling, ohmic heating, electrical transients, vibration, chemical contamination, corrosion, or oxidation during operation may experience increased resistance of connection. There have been limited numbers of age-related failures of cable connections reported. An applicant's operating experience with detection of aging effects should be adequate to demonstrate that the program is capable of detecting the presence or noting the absence of aging effects for December 2010 XI E6-3 NUREG-1801, Rev. 2 OAG10001390_00751
electrical cable connections where a one-time inspection is used to confirm the effectiveness of another preventive or mitigative AMP.
This AMP considers the technical information and guidance provided in NUREG/CR-5643, SAND96-0344, IEEE Std. 1205-2000, EPRI 109619, EPRI 104213, NEI White Paper on AMP XI.E6, Final License Renewal Interim Staff Guidance LR-ISG-2007-02, Staff Response to the NEI White Paper on AMP XI.E6, Licensee Event Report (LER) 361 2007005, LER 3612007006 and LER 3612008006.
References 10 CFR Part 50, Appendix 8, Quality Assurance Criteria for Nuclear Power Plants, Office of the Federal Register, National Archives and Records Administration, 2009.
EPRI 104213, Bolted Joint Maintenance & Application Guide, Electric Power Research Institute, Palo Alto, CA, December 1995.
EPRI 109619, Guideline for the Management of Adverse Localized Equipment Environments, Electric Power Research Institute, Palo Alto, CA, June 1999.
Final License Renewal Interim Staff Guidance LR-ISG-2007-02: Changes to Generic Aging Lesson Learned (GALL) Report Aging Management Program (AMP) XI.E6, Electrical Cable Connections Not Subject to 10 CFR 50.49 Environmental Qualification Requirements, 74 FR 68287, U.S. Nuclear Regulatory Commission, December 23,2009.
IEEE Std. 1205-2000, IEEE Guide for Assessing, Monitoring and Mitigating Aging Effects on Class 1E Equipment Used in Nuclear Power Generating Stations.
Licensee Event Report 361 2007005, San Onofre Unit 2, Loose Electrical Connection Results in Inoperable Pump Room Cooler, U.S. Nuclear Regulatory Commission.
Licensee Event Report 3612007006, San Onofre Units 2 and 3, Loose Electrical Connection Results in One Train of Emergency Chilled Water (ECIIV) System Inoperable, U.S. Nuclear Regulatory Commission.
Licensee Event Report 3612008006, San Onofre 2, Loose Connection Bolting Results in Inoperable Battery and TS Violation, U.S. Nuclear Regulatory Commission.
NEI White Paper, GALL AMP XI.E6 (Electrical Cables), Nuclear Energy Institute, September 5, 2006. (ADAMS Accession Number ML062770105)
NUREG/CR-5643, Insights Gained From Aging Research, U.S. Nuclear Regulatory Commission, March 1992.
SAND96-0344, Aging Management Guideline for Commercial Nuclear Power Plants - Electrical Cable and Terminations, prepared by Sandia National Laboratories for the U.S. Department of Energy, September 1996.
Staff's Response to the NEI White Paper on Generic Aging Lessons Learned (GALL) Report Aging Management Program (AMP) XI.E6, Electrical Cable Connections Not Subject to NUREG-1801, Rev. 2 XI E6-4 December 201 0 OAG10001390_00752
10 CFR 50.49 Environmental Qualification Requirements, U.S. Nuclear Regulatory Commission, March 16,2007. (ADAMS Accession Number ML070400349)
December 2010 XI E6-S NUREG-1801, Rev. 2 OAG10001390_00753
APPENDIX QUALITY ASSURANCE FOR AGING MANAGEMENT PROGRAMS December 201 0 A-i NUREG-1801, Rev. 2 OAGI0001390_00754
QUALITY ASSURANCE FOR AGING MANAGEMENT PROGRAMS The license renewal applicant must demonstrate that the effects of aging on structures and components (SC) subject to an aging management review (AMR) will be managed in a manner that is consistent with the CLB of the facility for the period of extended operation. Therefore, those aspects of the AMR process that affect the quality of safety-related SCs are subject to the quality assurance (QA) requirements of Appendix B to 10 CFR Part 50. For non-safety-related SCs subject to an AMR, the existing 10 CFR Part 50, Appendix B, QA program may be used to address the elements of corrective actions, confirmation process, and administrative controls on the following bases:
Criterion XVI of 10 CFR Part 50, Appendix B, requires that measures be established to ensure that conditions adverse to quality, such as failures, malfunctions, deviations, defective material and equipment, and non-conformances, are promptly identified and corrected. In the case of significant conditions adverse to quality, measures must be implemented to ensure that the cause of the condition is determined and that corrective action is taken to preclude repetition. In addition, the cause of the significant condition adverse to quality and the corrective action implemented must be documented and reported to appropriate levels of management.
To preclude repetition of significant conditions adverse to quality, the confirmation process element (Element 8) for license renewal AMPs consists of follow-up actions to verify that the corrective actions implemented are effective in preventing a recurrence. As an example, for the management of internal piping corrosion, the AMP XI.M2, "Water Chemistry," may be used to minimize the piping's susceptibility to corrosion. However, it also may be necessary to institute a condition monitoring program that uses ultrasonic inspection to verify that corrosion is indeed insignificant.
10 CFR 50.34(b)(6)(i) requires that the final safety analysis report submitted by a nuclear power plant license applicant includes information on the applicant's organizational structure, allocations of responsibilities and authorities, and personnel qualification requirements. 10 CFR 50.34(b)(6)(ii) also notes that Appendix B to 10 CFR Part 50 sets forth the requirements for managerial and administrative controls used for safe operation.
Pursuant to 10 CFR 50.36(c)(5), administrative controls related to organization and management, procedures, record keeping, review and audit, and reporting ensure the safe operation of the facility. Programs that are consistent with the requirements of 10 CFR Part 50, Appendix B, also satisfy the administrative controls element necessary for AMPs for license renewal.
Notwithstanding the suitability of its provisions to address quality-related aspects of the AMR process for license renewal, 10 CFR Part 50, Appendix B, covers only safety-related SCs.
Therefore, absent a commitment by the applicant to expand the scope of its 10 CFR Part 50, Appendix B, QA program to include non-safety-related structures and components subject to an AMR for license renewal, the AMPs applicable to non-safety-related SCs include alternative means to address corrective actions, confirmation processes, and administrative controls. Such alternate means are subject to review by the NRC on a case-by-case basis.
December 201 0 A-1 NUREG-1801, Rev. 2 OAG10001390_00755
NRC FORM 335 U.S. NUCLEAR HEGULATORY COMMISSION REPOF,' NUMB::'K (A,5si~n<?d by NRC, Add Vol.. SUP'::,) Rev.,
~RCMD 3.7 iJ:nd Add6'Mdum Numbers, if any.;
BiBLIOGRAPHiC DATA SHEET NUREG ',801. Revision 2 Generic Aging Lessons Leamed (GALL) Report December 2010
- 4. ;:IN OR GR.A.N~ NUMbS"
- 5. AU:HOR(S)
U.S. Nuciear Regulatory Commission j'(' Pf:'R10D COVERED I;nci.,.>;,," Da~~s) l
.8. PE:!:ZFORM~NG OR.GAN!Z,AT!ON ." NAr.;1:: AND ,ADDRESS {if NRC. p;\)v;*:/e O:v,sion Office Of Regj~>n. U,S Nucie;;;r .R.&dLdatoty Ct")mmission ana :nailing ac:ort:ss, :f contracto:
D(c:/lde ,"";ame ana' flw:img adumss.}
Di\{ision of License Renewal Omce of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission
\N,:lshington, DC 20555**00G1
~, SPONSOR;NG ORGANiZATiON* NAME AND ADDRESS (if l\iRe, iYPf5 "Sarne as above" if~ontrdcto;, prm!}de NF-?C DJ'I/S,Ion, Off.lce or i<f:g;[;{,' f) 5 r'li{"c/ea: F,'eyu!atoIY C'o;rnm,l$'.i:lX; e.nc: m8i!itJ9 ?ddres~* ;
Same as itern 8, above 10 SUPPLl'MENT.A$Y NOTES Revision 2 consolidates NUREG-18Q1. Vojume 1 and Volume 2 into one volume.
- he Generic .Aging U::ssons L.earned (GALL) Report contains the staft's generic ev aluatior: ot the exist:ng plant p:-(lg!amS and docurnents the iechnical basis Tor determining where existing pwgrams are adequ ate without modification and where 9xistmg p:'ograms should be augmented for the period of extended operation The evaiuatl or. results documented in the GALl.. Repo:1 indicate that many of tile existing programs are adequate to manage the aging effects for particular structures or components fo: license renewal without change. The GALL Report also contains recommendatio ns on specific areas lor wh:ch existing
>Jrograrns should be augmented for !icense renewal. An Applicant may reference th e GAl-L Report in a license renews:
appiication to demonstrate thai the programs at the applicant's facility corres pond to those review'ed and approved in the GilL...
Report However, if an app!icant takes credit for a program in the GAU_ Report, it is incumbent on t;;e appiicant to enS'Jre that tr,e conditions and operating experience at the plant are bounded by the conditi ons and operating experience for v.;h:ch the GALL Report program was evaluated. If these bounding conditions are not met, it is incumbent for the applicant to address the additional aging effects and augment the GALL Report programs as appropriate. T he staff will verify that the applicant's pcograrns are consistent with those described in the GALL Report and/Oi with pia nt conditions and cperating eKperience during t1",e performance of an aging management audit The focus of the balance of the staffs re'v'iew of a license renewal application is on those programs that an applicant has enhanced to be consistent with the G ALl.. Report. those prog,ams that an applicant has taken an exception io the program described in lhe GALL Report. and piant-s pecific programs not described in the GALl..
Report. The information in tfle GALL Repo!i has been incorporated into the NUREG -1800, "Standard review Pian for r~eview or license ~~enewai Appiications for Nuciear Power Plants" as directed by the Cornmi 55ion, to improve the efficiency of the license renewal process.
Aging NUclear Safety I';') }i;~;;;:::';~"':: ;c.,:,';; :;:",,()I:
Aging Mechanisms ~ unc~assif!ed l~,9ing Effects I*{ih i., e"p0rt' ........ .
.A.ging Management Programs
~ unc:asHit1ed ll:. NUMBER OF P."GE.S L,
l PRiCE OAGI0001390_00756