Implementation of ASME Code, Section XI, Code Case N-770, on Alternative Examination Requirements for Class 1 Butt Welds Fabricated with Alloy 82/182

Conference · Mon Sep 17 00:00:00 EDT 2012

OSTI ID:1053385

Sullivan, Edmund J; Anderson, Michael T

In May 2010, the NRC issued a proposed notice of rulemaking that includes a provision to add a new section to its rules to require licensees to implement 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 W86182 Weld Filler Material With or Without the Application of Listed Mitigation Activities, Section XI, Division 1,’’ with 15 conditions. Code Case N-770 contains baseline and inservice inspection (ISI) requirements for unmitigated butt welds fabricated with Alloy 82/182 material and preservice and ISI requirements for mitigated butt welds. The NRC stated that application of ASME Code Case N-770 is necessary because the inspections currently required by the ASME Code, Section XI, were not written to address stress corrosion cracking Alloy 82/182 butt welds, and the safety consequences of inadequate inspections can be significant. The NRC expects to issue the final rule incorporating this code case into its regulations in the spring 2011 time frame. This paper discusses the new examination requirements, the conditions that NRC is imposing , and the major concerns with implementation of the new Code Case.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1053385
• Report Number(s): PNNL-SA-78592; 401001060
• Resource Relation: Conference: Proceedings of the ASME Pressure Vessels and Piping Conference (PVP2011), July 17-21, 2011, Baltimore, Maryland, Paper No. PVP2011-58041
• Country of Publication: United States
• Language: English

Related Subjects

Inservice inspection
ultrasonic inspection
alloy 82/182
butt weld