Subsection ISTD of ASME’s Operation and Maintenance of Nuclear Power Plants (OM Code) is the required code for preservice and inservice examination and testing of dynamic restraints (snubbers). This code replaced the inspection requirements of Article IWF-5000, “Inservice Inspection Requirements for Snubbers,” in Section XI, “Inservice Inspection of Nuclear Power Plant Components,” of the ASME Boiler and Pressure Vessel Code after the publication of the 2006 addenda to Section XI, which deleted Article IWF-5000. When the requirements of IWF-5000 were deleted, the requirements for examination and testing of snubbers, as required by Section 50.55a, “Codes and Standards,” of Title 10, “Energy,” of the Code of Federal Regulations (10 CFR 50.55a) became those specified by Subsection ISTD of the ASME OM Code. Therefore, when nuclear power plant owners prepare their ten-year inservice testing (IST)/inservice inspection (ISI) program updates that incorporate the 2006 (or later) addenda to Section XI, the snubber requirements will be required to be in accordance with those of Subsection ISTD of the latest approved edition and addenda of the ASME OM Code (2004 Edition with Addenda through 2006). This edition of the ASME OM Code is cited in the NRC Rulemaking which was published on June 21, 2011.

Because this is a change in requirements, owners should be asking some of the following questions: What is the difference between our existing program requirements and those included in Subsection ISTD of the ASME OM Code? How will this change our existing program or the way the current snubber examination and testing program is implemented? How much effort will be required to implement this program change? This paper will provide some specific guidance for the implementation of the ISTD Code and will identify typical areas where changes may be required to existing snubber examination and testing programs. It will also describe some approaches to satisfy the requirements of ISTD-6000, “Service Life Monitoring,” which might not have been included in the previous requirements under Section XI.

Paper published with permission.

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