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ASME Section XI (Rules for In-Service Inspection of Nuclear Powers Plant Components)


ASME Section XI comprises three divisions, each covering rules for inspection and testing of components of different types of nuclear power plants. These three divisions are as follows:

  • ASME Section XI, Division 1: Rules for Inspection and Testing of Components of Light-Water-Cooled Plants

  • ASME Section XI, Division 2: Rules for Inspection and Testing of Components of Gas-Cooled Plants

  • ASME Section XI, Division 3: Rules for Inspection and Testing of Components of Liquid-Metal-Cooled Plants.

Since the publication of the first edition of ASME Section XI in 1971, significant changes and additions have been incorporated, and as such, the organization of the later versions of ASME Section XI, Division 1, is considerably different from that of the first edition.

ASME Section XI, Division 1, provides the rules and requirements for in-service inspection and testing of light-water-cooled nuclear power plants. The rules and requirements identify, as a minimum, the areas subject to inspection, responsibilities, provisions for accessibility and inspectability, examination methods and procedures, personnel qualifications, frequency of inspection, record-keeping and report re- quirements, procedures for evaluating inspection results, subsequent disposition of results of evaluations, and repair requirements.

Division 1 also provides for the design, fabrication, installation, and inspection of replacements. The jurisdiction of Division 1 of ASME Section XI covers individual components and complete power plants that have met all the requirements of the construction code, commencing at that time when the construction code require- ments have been met, irrespective of physical location.

When portions of systems or plants are completed at different times, the jurisdic- tion of Division 1 shall cover only those portions on which all of the construction code requirements have been met. Rules of ASME Section XI apply to ASME Classes 1, 2, 3, and MC components and their supports, core support structures, pumps, and valves.

Rules of ASME Section XI, Division 1, apply to modifications made to ASME III components and their supports after all of the original construction code require- ments have been met.

Rules of ASME Section XI, Division 1, apply to systems, portions of systems, components, and their supports not originally constructed to ASME Section III requirements but based on their importance to safety if they were classified as ASME Classes 1, 2, 3, and MC.

Effective Edition, Addenda, and Code Cases

Section 10 CFR 50.55a, Codes and Standards, of the Code of Federal Regulations requires compliance with ASME Section XI for operating nuclear power plants. In addition, 10 CFR 50.55a, Paragraph (b)(2) delineates the editions and addenda of ASME Section XI that are approved for use. Only the approved editions and addenda of ASME Section XI are to be used. The latest published edition and addenda may not be approved by the U.S. NRC; therefore, they can only be used after seeking special permission from the U.S. NRC.

It is recommended that one refer to 10 CFR 50.55a from time to time to determine which edition and addenda of ASME Section XI have been approved by the U.S. NRC and which edition and addenda may be applicable to a nuclear power plant at a particular time.

The requirements of 10 CFR 50.55a are based on the construction permit (CP) docket date and the operating license (OL) date of the nuclear plant.

Code editions and addenda later than those established for a particular application in conformance with the requirements of 10 CFR 50.55a may be used provided they are approved and all related requirements of respective editions or addenda are met.

While establishing a particular edition and addenda of ASME Section XI, consider the limitations and modifications to the specific editions and addenda delineated in Paragraph (b)(2) of 10 CFR 50.55a, and ensure compliance to those limitations and modifications, as applicable.

For repairs and replacements, the applicable edition and addenda shall be the one in effect for that in-service inspection (ISI) interval during which the repairs and replacements are to be made. Refer to articles IWA-4000 and IWA-7000 of ASME Section XI.

Applicable Code Cases

Like the code edition and addenda, code cases are regularly reviewed by the U.S. NRC. The U.S. NRC–approved code cases with or without limitations or additional requirements are published in the Regulatory Guide 1.147, In-Service Inspection Code Case Acceptability of ASME Section XI, Division 1.4

Acceptance or endorsement by the U.S. NRC staff applies only to those code cases or code case revisions with the date of ASME Council approval, as shown in the Regulatory Guide 1.147. #Little_PEng

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