Resolution of Generic Safety Issues: Issue 190: Fatigue Evaluation of Metal Components for 60-Year Plant Life (Rev. 2) ( NUREG-0933, Main Report with Supplements 1–35 )

DESCRIPTION

The risk of failure from fatigue of various reactor coolant system components was studied under Issue 78 and later integrated into the NRR Fatigue Action Plan which was completed and documented in SECY-95-245.⁵⁴⁷ The staff concluded that the risk from fatigue failure of the primary coolant pressure boundary components is very small; this conclusion was based on a plant life of 40 years. The impact of a license renewal period of 20 years on fatigue of metal components was to be considered in the resolution of Issue 166,¹⁵⁶⁴ but Issue 190 was established to address this subject separately.⁹²⁸

CONCLUSION

Based on the existence of an ongoing action plan⁹²⁸ to address the safety concern and the NRR decision¹⁵¹⁷ to pursue its resolution, the issue was considered nearly-resolved in August 1996. It was later given a high priority ranking in SECY-98-166.¹⁷¹⁸

In resolving the issue, the staff performed probabilistic analyses which showed low core damage frequencies resulting from fatigue failure of metal components. However, the nature of age-related degradation indicated the potential for an increase in the frequency of pipe leaks as plants continue to operate. Consistent with 10 CFR 54.21, "Requirements for Renewal of Operating Licenses for Nuclear Power Plants: Contents of Application - Technical Information," licensees will have to address the effects of the reactor coolant system environment on component fatigue life, as aging management programs are formulated in support of license renewal. Thus, the issue was RESOLVED with no new or revised requirements.¹⁷⁶⁴

REFERENCES

0547. SECY-95-245, "Completion of the Fatigue Action Plan," U.S. Nuclear Regulatory Commission, September 25, 1995. [9509290040] 0928. Memorandum for A. Thadani from T. Speis, "Generic Safety Issue (GSI)-166, 'Adequacy of Fatigue Life of Metal Components,'" August 26, 1996. [9808210022] 1517. Memorandum for J. Sniezek from T. Murley and E. Beckjord, "Resolution of Fatigue and Environmental Qualification Issues Related to License Renewal," April 1, 1993. [9304270324] 1564. Memorandum for W. Russell from E. Beckjord, "License Renewal Implications of Generic Safety Issues (GSIs) Prioritized and/or Resolved Between October 1990 and March 1994," May 5, 1994. [9406170365] 1718. SECY-98-166, "Summary of Activities Related to Generic Safety Issues," U.S. Nuclear Regulatory Commission, July 6, 1998. [9807220129, 9807170226] 1764. Memorandum for W. Travers from A. Thadani, "Closeout of Generic Safety Issue 190, 'Fatigue Evaluation of Metal Components for 60-Year Plant Life,'" December 26, 1999.