1801 R0 XI.S5

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Xl.S5 MASONRY WALL PROGRAM

Program Description

U.S. Nuclear Regulatory Commission (NRC) IE Bulletin (IEB) 80-11, "Masonry Wall Design," and US 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 the identification of masonry walls in close proximity to, or having attachments from, safety-related systems or components, and the evaluation of design adequacy and construction practice. US 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 US NRC IEB 80-11 is not invalidated by (1) deterioration of the masonry walls (e.g., new cracks not considered in the reevaluation), (2) physical plant changes such as installation of new safety-related systems or components in close proximity to masonry walls, or (3) reclassification of systems or components from non-safety-related to safety-related.

Important elements in the evaluation of many masonry walls during the US NRC IEB 80-11 program included (1) installation of steel edge supports to provide a sound technical basis for boundary conditions used in seismic analysis and (2) installation of steel bracing to ensure 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 objective of the masonry wall program is to manage aging effects so that the evaluation basis established for each masonry wall within the scope of license renewal remains valid through the period of extended operation. Since the issuance of US NRC IEB 80-11 and US NRC IN 87-67, the US NRC promulgated 10 CFR 50.65, the Maintenance Rule. Masonry walls may be inspected as part of the Structures Monitoring Program ( XI.S6) conducted for the Maintenance Rule], provided the ten attributes described below are incorporated.

The attributes of an acceptable Masonry Wall Program are described below.

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.

2. Preventive Action: No specific preventive actions are required.

3. Parameters Monitored or Inspected: The primary parameter monitored is wall cracking that could potentially invalidate the evaluation basis.

4. Detection of Aging Effects: Visual examination of the masonry walls by qualified inspection personnel is sufficient. The frequency of inspection is selected to ensure there is no loss of intended function between inspections. The inspection frequency may vary from wall to wall, depending on the significance of cracking in the evaluation basis. Unreinforced masonry walls that have not been contained by bracing warrant the most frequent inspection, because the development of cracks may invalidate the existing evaluation basis.

5. Monitoring and Trending: Trending is not required. Monitoring is achieved by periodic examination for cracking.

6. Acceptance Criteria: For each masonry wall, the extent of observed cracking of masonry and degradation of steel edge supports and bracing is not to invalidate the evaluation basis. Corrective actions are taken if the extent of cracking and steel degradation is sufficient to invalidate the evaluation basis. An option is to develop a new evaluation basis that accounts for the degraded condition of the wall (i.e., acceptance by further evaluation).

7. Corrective Actions: As discussed in the appendix to this report, the staff finds the requirements of 10 CFR 50, Appendix B, acceptable to address corrective actions.

8. Confirmation Process: As discussed in the appendix to this report, the staff finds the requirements of 10 CFR 50, Appendix B, acceptable to address the confirmation process.

9. Administrative Controls: As discussed in the appendix to this report, the staff finds the requirements of 10 CFR 50, Appendix B, acceptable to address administrative controls.

10. Operating Experience: Since 1980, masonry walls that perform an intended function have been systematically identified through licensee programs in response to US NRC IEB 80-11, USI A-46, and 10 CFR 50.48. US NRC IN 87-67 documented lessons learned from the US 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. Whether conducted as a stand-alone program or as part of structures monitoring for MR, a masonry wall AMP that incorporates the recommendations delineated in US 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 50.48, Fire Protection, Office of the Federal Register, National Archives and Records Administration, 2000.

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, 2000.

US 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.

US NRC IE Bulletin 80-11, Masonry Wall Design, U.S. Nuclear Regulatory Commission, May 8, 1980.

US 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.

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

United States of America

Aging Management Program