XI.M8 (NUREG-2191 R0)
XI.M8 BWR PENETRATIONS
Program Description
The program for boiling water reactor (BWR) vessel instrumentation penetrations, control rod drive (CRD) housing and incore-monitoring housing (ICMH) penetrations and standby liquid control (SLC) nozzles/Core ΔP nozzles includes inspection and flaw evaluation in conformance with the guidelines of staff-approved Boiling Water Reactor Vessel and Internals Project (BWRVIP) Topical Reports BWRVIP-49-A, BWRVIP-47-A and BWRVIP-27-A. The program manages cracking due to cyclic loading, stress corrosion cracking (SCC) and intergranular stress corrosion cracking (IGSCC) for these BWR vessel penetrations and nozzles. The inspection and evaluation guidelines of BWRVIP-49-A, BWRVIP-47-A and BWRVIP-27-A contain generic guidelines intended to present appropriate inspection recommendations to assure safety function integrity. The guidelines of BWRVIP-49-A provide information on the type of instrument penetration, evaluate their susceptibility and consequences of failure, and define the inspection strategy to assure safe operation. The guidelines of BWRVIP-47-A provide information on components located in the lower plenum region of BWRs, evaluate their susceptibility and consequences of failure, and define the inspection strategy to assure safe operation. The guidelines of BWRVIP-27-A are applicable to plants in which the SLC system injects sodium pentaborate into the bottom head region of the vessel (in most plants, as a pipe within a pipe of the core plate ΔP monitoring system). The BWRVIP-27-A guidelines address the region where the ΔP and SLC nozzle or housing penetrates the vessel bottom head and include the safe ends welded to the nozzle or housing. Guidelines for repair design criteria are provided in BWRVIP-57-A(Archived) for instrumentation penetrations, BWRVIP-55-A for CRD housing and ICMH penetrations and BWRVIP-53-A for SLC line.
Although this is a condition monitoring program, control of water chemistry helps prevent SCC and IGSCC. The water chemistry program for BWRs relies on monitoring and control of reactor water chemistry based on industry guidelines, such as BWRVIP-190 (EPRI 1016579)(Archived) or later revisions. BWRVIP-190(Archived) has three sets of guidelines: (i) one for primary water, (ii) one for condensate and feedwater, and (iii) one for CRD mechanism cooling water. Adequate aging management activities for these components provide reasonable assurance of the long-term integrity and safe operation of BWR vessel instrumentation nozzles, CRD housing and ICMH penetrations and SLC nozzles/Core ΔP nozzles.
Evaluation and Technical Basis
- 1. Scope of Program: The scope of this program is applicable to BWR instrumentation penetrations, CRD housing and ICMH penetrations and BWR SLC nozzles/Core ΔP nozzles. The program manages cracking due to cyclic loading or SCC and IGSCC using inspection and flaw evaluation in accordance with the guidelines of staff-approved BWRVIP-49-A, BWRVIP-47-A and BWRVIP-27-A.
- 2. Preventive Actions: This program is a condition monitoring program and has no preventive actions. However, maintaining high water purity reduces susceptibility to SCC or IGSCC. The program description, evaluation, and technical basis of water chemistry are presented in the Generic Aging Lessons Learned for Subsequent License Renewal (GALL-SLR) Report aging management program (AMP) XI.M2, “Water Chemistry.”
- 3. Parameters Monitored or Inspected: The program manages the effects of cracking due to SCC/IGSCC on the intended function of the BWR instrumentation nozzles, CRD housing and ICMH penetrations, and BWR SLC nozzles/Core ΔP nozzles. The program monitors for evidence of surface-breaking linear discontinuities if a visual inspection technique is used or for relevant flaw signals if a volumetric ultrasonic testing (UT) method is used. In addition, the program includes visual examination to confirm the absence of leakage.
- 4. Detection of Aging Effects: The inspection guidelines of BWRVIP-49-A, BWRVIP-47-A and BWRVIP-27-A, along with the existing inspection requirements in American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code), Section XI, Table IWB-2500-1, are sufficient to monitor for indications of cracking in BWR instrumentation nozzles, CRD housing and ICMH penetrations and BWR SLC nozzles/Core ΔP nozzles, and should continue to be followed for the subsequent period of extended operation. The extent and schedule of the inspection and test techniques prescribed by the staff-approved BWRVIP inspection guidelines and the ASME Code, Section XI program are designed to maintain structural integrity, to detect aging effects, and to perform repair or replacement before the loss of intended function of the component.
- Instrument penetrations, CRD housing and ICMH penetrations and SLC system nozzles or housings are inspected in accordance with the staff-approved BWRVIP inspection guidelines and the requirements in the ASME Code, Section XI. These examination categories include volumetric examination methods (UT or radiography testing), surface examination methods (liquid penetrant testing or magnetic particle testing), and VT-2 visual examination methods.
- 5. Monitoring and Trending: Inspections scheduled in accordance with ASME Code, Section XI, IWB-2400 and approved BWRVIP-49-A, BWRVIP-47-A and BWRVIP-27-A provides timely detection of cracks. The scope of examination and reinspection is expanded beyond the baseline inspection if flaws are detected. Any indication detected is evaluated in accordance with ASME Code, Section XI or other acceptable flaw evaluation criteria, such as the staff-approved BWRVIP-49-A, BWRVIP-47-A or BWRVIP-27-A guidelines. Applicable and approved BWRVIP-14-A, BWRVIP-59-A, and BWRVIP-60-A documents provide additional guidelines for the evaluation of crack growth in stainless steels (SSs), nickel alloys, and low-alloy steels, respectively.
- 6. Acceptance Criteria: Acceptance criteria are given in BWRVIP-49-A for instrumentation nozzles, BWRVIP-47-A for CRD housing and ICMH penetrations, and BWRVIP-27-A for BWR SLC nozzles/Core ΔP nozzles.
- 7. Corrective Actions: Results that do not meet the acceptance criteria are addressed in the applicant’s corrective action program under those specific portions of the quality assurance (QA) program that are used to meet Criterion XVI, “Corrective Action,” of 10 CFR Part 50, Appendix B. Appendix A of the GALL-SLR Report describes how an applicant may apply its 10 CFR Part 50, Appendix B, QA program to fulfill the corrective actions element of this AMP for both safety-related and nonsafety-related structures and components (SCs) within the scope of this program.
- Corrective actions include repair and replacement procedures in staff-approved BWRVIP-57-A(Archived), BWRVIP-55-A, BWRVIP-58-A and BWRVIP-53-A that are equivalent to those required in ASME Code, Section XI. Guidelines for repair design criteria are provided in BWRVIP-57-A(Archived) for instrumentation penetrations, BWRVIP-55-A for CRD housing and ICMH penetrations, and BWRVIP-53-A for SLC line. BWRVIP-58-A provides guidelines for internal access weld repair for CRD penetrations.
- 8. Confirmation Process: The confirmation process is addressed through those specific portions of the QA program that are used to meet Criterion XVI, “Corrective Action,” of 10 CFR Part 50, Appendix B. Appendix A of the GALL-SLR Report describes how an applicant may apply its 10 CFR Part 50, Appendix B, QA program to fulfill the confirmation process element of this AMP for both safety-related and nonsafety-related SCs within the scope of this program.
- The staff finds that licensee implementation of the guidelines in BWRVIP-49-A, BWRVIP-47-A and BWRVIP-27-A, as modified, provides 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: Administrative controls are addressed through the QA program that is used to meet the requirements of 10 CFR Part 50, Appendix B, associated with managing the effects of aging. Appendix A of the GALL-SLR Report describes how an applicant may apply its 10 CFR Part 50, Appendix B, QA program to fulfill the administrative controls element of this AMP for both safety-related and nonsafety-related SCs within the scope of this program.
- 10. Operating Experience: Cracking due to SCC or IGSCC has occurred in BWR components made of austenitic SSs and nickel alloys. The program guidelines are based on an evaluation of available information, including BWR inspection data and information about the elements that cause IGSCC, to determine which locations may be susceptible to cracking. Implementation of the program provides reasonable assurance that cracking will be adequately managed so the intended functions of the instrument penetrations and SLC system nozzles or housings will be maintained consistent with the CLB for the subsequent period of extended operation.
- The program is informed and enhanced when necessary through the systematic and ongoing review of both plant-specific and industry operating experience including research and development such that the effectiveness of the AMP is evaluated consistent with the discussion in Appendix B of the GALL-SLR Report.
References
10 CFR Part 50, Appendix B, “Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants.” Washington, DC: U.S. Nuclear Regulatory Commission. 2016.
10 CFR 50.55a, “Codes and Standards.” Washington, DC: U.S. Nuclear Regulatory Commission. 2016.
ASME. ASME Code Section XI, “Rules for Inservice Inspection of Nuclear Power Plant Components.” New York, New York: The American Society of Mechanical Engineers. 2008.
EPRI. BWRVIP-14-A (EPRI 1016569), “BWR Vessel and Internals Project, Evaluation of Crack Growth in BWR Stainless Steel RPV Internals.” Palo Alto, California: Electric Power Research Institute. September 2008.
_____. BWRVIP-27-A (EPRI 1007279), “BWR Vessel and Internals Project, BWR Standby Liquid Control System/Core Plate ΔP Inspection and Flaw Evaluation Guidelines.” Palo Alto, California: Electric Power Research Institute. August 2003.
_____. BWRVIP-47-A (EPRI 1009947), “BWR Vessel and Internals Project, BWR Lower Plenum Inspection and Flaw Evaluation Guidelines.” Palo Alto, California: Electric Power Research Institute. November 2004.
_____. BWRVIP-49-A (EPRI 1006602), “BWR Vessel and Internals Project, Instrument Penetration Inspection and Flaw Evaluation Guidelines.” Palo Alto, California: Electric Power Research Institute. 2002.
_____. BWRVIP-53-A (EPRI 1012120), “BWR Vessel and Internals Project, Standby Liquid Control Line Repair Design Criteria.” Palo Alto, California: Electric Power Research Institute. September 2005.
_____. BWRVIP-55-A (EPRI 1012117), “BWR Vessel and Internals Project, Lower Plenum Repair Design Criteria.” Palo Alto, California: Electric Power Research Institute. September 2005.
_____. BWRVIP-57-A (EPRI 1012111)(Archived), “BWR Vessel and Internals Project, Instrument Penetration Repair Design Criteria.” Palo Alto, California: Electric Power Research Institute. September 2005.
_____. BWRVIP-58-A (EPRI 1012618), “BWR Vessel and Internals Project, CRD Internal Access Weld Repair.” Palo Alto, California: Electric Power Research Institute. 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.” Palo Alto, California: Electric Power Research Institute. 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.” Palo Alto, California: Electric Power Research Institute. June 2003.
_____. BWRVIP-190 (EPRI 1016579)(Archived), “BWR Vessel and Internals Project, BWR Water Chemistry Guidelines-2008.” Palo Alto, California: Electric Power Research Institute. October 2008.