**ASME CODE CLASSIFICATIONS FOR COMPONENTS

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1 Introduction **ASME CODE CLASSIFICATIONS FOR COMPONENTS The current scope of the IST requirements of 10CFR50.55a includes ASME Code Class 1, 2, and 3 components. Therefore, ASME Section XI Code classification of systems and components determine the examinations and tests required for the purposes of inservice inspection, inservice testing and repair/replacement activities. Many of the problems regarding improper program scope originate from improper classification of components. The process of classifying components is rather straightforward for newer plants that were designed and constructed to ASME Section III. Federal regulations required that components in plants whose application for a construction permit was docketed after May 14, 1984 meet the requirements of ASME Section III. However, the older plants were designed and constructed to the United States of America Standards (USAS) B31.1, Code of Power Piping, and B31.7, Code for Nuclear Power Piping. ASME Section XI requirements for inservice inspection and testing were imposed after the design and/or construction of these plants were completed. Additionally, the early editions of Section XI did not include the categorizations of Class 1, 2, and 3. These component classifications were added in subsequent editions between 1971 and For these older plants, safety-related components are classified based on the function of the components; hence the wording from 10CFR50.55a(f): "(1) For a boiling or pressurized water-cooled nuclear power facility whose construction permit was issued prior to January 1, 1971, pumps and valves must meet the test requirement of paragraphs (f)(4) and (5) of this section to the extent practical. Pumps and valves that are part of the reactor coolant pressure boundary must meet the requirements applicable to components that are classified as ASME Code Class 1. Other safetyrelated pumps and valves must meet the requirements applicable to components that are classified as ASME Code Class 2 or Class 3." "(2) For a boiling or pressurized water-cooled nuclear power facility whose construction permit was issued on or after January 1, 1971, but before July 1, 1974, pumps and valves which are classified as ASME Code Class 1 and Class 2 must be designed and be provided with access to enable the performance of inservice tests for operational readiness set forth in editions of Section XI of the ASME Boiler and Pressure Vessel Code and Addenda in effect 6 months prior to the date of issuance of the construction permit."

2 "(3) For a boiling or pressurized water-cooled nuclear power facility whose construction permit was issued on or after January 1, 1974: (iii) Pumps and valves which are classified as ASME Code Class 1 must be designed and be provided with access to enable the performance of inservice tests for assessing operational readiness set forth in Section XI... (iv) Pumps and valves which are classified as ASME Code Class 2 and Class 3 must be designed and be provided with access to enable the performance of inservice testing of pump and valves for assessing operational readiness set forth in Section XI..." Because early vintage nuclear plants were designed and constructed before Section III of the ASME Boiler and Pressure Vessel Code was incorporated into 10CFR50.55a, the ASME Section XI Code classifications for ISI may differ from the original design classifications. However, while the ASME Code classifications determine the rules for repairs and replacements and the component inspection requirements, all repairs and replacements are performed to meet, at a minimum, the specifications of the original design code. Historically. the safety-related classification process and criteria have not been clearly defined. Various documents used in this process have alluded to such phrases as "safety-related" or "important to safety" but no complete, consistent guideline existed as to why some equipment is more important to nuclear safety than other equipment or what documents are applicable. As a result, various interpretations/inconsistencies have evolved in the use of the term "safetyrelated", often times confusing regulatory and other non-functional requirements into its applicability. Other phrases widely used in codes, standards, and other documents have also been correctly and incorrectly interpreted to be synonymous to "safety-related". "Basic component" defined in 10CFR21 is equivalent to "safety-related." "Important to Safety," which was previously used as a synonym to "safetyrelated," is currently an unresolved NRC generic issue and officially undefined. The facility Final Safety Analysis Report (FSAR) frequently uses the term "safety" in a broader context than "safety-related". FSARs use phrases such as "safety functions", "nuclear safety systems", "instruments required for safety" and others. The relationship of the term "safety-related" to those other commonly referred to terms such as "safety", "protection systems" etc. are not necessarily synonymous with the term "safety-related".

3 There also exists further confusion regarding the term "safety-related". This confusion results from the different uses and interpretations applied to this term. The term safety-related is typically used in the following ways: a. From a design engineering standpoint, the term "safety-related" is used to identify items which are (1) part of the reactor coolant pressure boundary, (2) required to shut down the reactor and maintain it in a safe shutdown condition, or (3) required to prevent or mitigate the consequences of accidents which could result in potential off-site exposures comparable to 10CFR guidelines. b. Typically, three methods of procurement are utilized, commonly referred to as: safety-related, commercial grade, and non-safety-related. A safetyrelated procurement refers to the purchase of an item under the provisions of 10CFR21 from a vendor with a quality assurance program that meets the requirements of 10CFR50 Appendix B. A commercial grade procurement refers to an item which will be dedicated for safety-related use, but is not purchased to an approved 10CFR50 Appendix B Quality Assurance program nor are 10CFR21 requirements imposed on the vendor. Once a commercial grade item is dedicated it becomes a basic component. A non-safety-related procurement refers to an item that does not have a safety-related function. c. Also, selected items may be classified as safety-related even though their function is non-safety-related. This is done to institute greater controls over procurement, maintenance, or replacement of such items. As a result, it is important to understand the context in which the term "safetyrelated" is used and what is meant. For component classification for the purposes of ISI and IST, the term "safety-related" pertains to the function a system or component performs. The "General Design Criteria for Nuclear Power Plant Construction Permits" was published for comment in the Federal Register in July The final version of these design criteria was not incorporated into the Code of Federal Regulations (10CFR50, Appendix A) until February 1971; therefore, many plants were designed prior to these requirements being finalized. These plants were typically designed and constructed based on the licensee's "interpretation of the intent of the Draft General Design Criteria published in July 1967". The design accepted by the NRC, any rules or requirements imposed by the NRC, commitments made by the licensee, and any exceptions to rules or requirements allowed when granting the facility license was granted from the design basis and licensing basis for that facility. The combination of the design basis, licensing basis and the system and component functions determine the requirements for inservice

4 testing and inspection. These determinations may be quite difficult and subject to opinion, which is precisely why they should be documented in a classification basis document. The basis document should define the test and examination boundaries and, in general, the examinations and tests required by the Section XI Code and federal regulations. Once established with a sound technical basis, these boundaries change only when systems and components are modified or replaced. A basis document provides the guidance needed for: The rational used for a defensible basis for safety classification; Assuring compliance with the law and the plant license basis such that all items required by the regulatory definition or by licensing commitment to be safetyrelated are identified as such; and Maintaining consistency with the current licensed plant design, with other plant equipment, and with past and current industry and NRC practice. Once the safety classification has been identified, the design and quality assurance requirements consistent with NRC regulations, industry standards and licensing basis can be identified. Some examples of classification basis documentation are included in Appendix C of these course notes. Classification Documents The following documents are used as guidance for the functional classification of systems, components, and component supports: NUREG-0800, Standard Review Plan, Section 3.2.2, Revision 1 (SRP 3.2.2) - This review plan is used by the NRC Office of Nuclear Reactor Regulation staff to review applications for construction and operation of nuclear power plants. SRP explains the staff policies and approach to system quality group classification. This document references Regulatory Guide 1.26, Revision 3, (RG 1.26) and "the corresponding ANS classification system of Safety Classes" (which refers to ANSI/ANS-52.1 or -51.1) as specific implementation documents for system classification. 10CFR50.55a, Codes and Standards - Sections 50.55a(c), (d), and (e) reference 10CFR50.2 and RG 1.26 for the classification of Quality Group A and Quality Group B and C components, respectively. Footnote 9 of 10CFR50.55a references RG 1.26 and SRP for guidance for quality group classification of components. 10CFR50.2, Reactor Coolant Pressure Boundary Definition - This section of the 1993 Edition of the Code of Federal Regulations provides criteria for the

5 classification of Quality Group A components. In previous issues of 10CFR, these criteria were provided in section 50.2(v). 10CFR50.55a(c)(2) - This paragraph provides exclusions from the criteria of Section 50.2, thus allowing components connected to the reactor coolant system to be Quality Group B (Section XI Code Class 2) or non-code Class. Regulatory Guide 1.26, Revision 3, (RG 1.26), Quality Group Classifications and Standards for Water-, Steam-, and Radioactive Waste Containing Components of Nuclear Power Plants - This document provides criteria for the classification of Quality Group B, C, and D (Typically non-code Class) components. ANSI/ANS , American National Standard, Nuclear Safety Criteria for the Design of Stationary Pressurized Water Reactor Plants - This document may be used as the basis for the examination and test boundaries or may be employed for guidance in cases where the requirements of RG 1.26 are vague or incomplete. It provides classification and design criteria for all safety-related components and is much more detailed and comprehensive than RG The classification and boundary criteria of Section are particularly useful in evaluating systems and components which were not designed to meet the valving criteria of RG 1.26, Footnote 4 or are not specifically covered by RG ANSI/ANS , American National Standard, Nuclear Safety Criteria for the Design of Stationary Boiling Water Reactor Plants - This document is essentially identical to ANSI/ANS , except that it specifically covers classification and design criteria for boiling water reactors. Per IWA-1400(a) of the Section XI, it is the owner's responsibility to determine the appropriate Code Classes for each component and to identify the system boundaries subject to inspection. IWA-1300 states that components identified for inspection and testing shall be included in the inservice inspection plan, and that the selection of components for the inservice inspection plan is subject to review by the regulatory and enforcement authorities having jurisdiction at the plant site. IWA-1320(a) states that the system group classification criteria of the regulatory authorities having jurisdiction at the power plant site governs the application of the rules of Section XI. IWA-1400(a), footnote 2, states that classification criteria are specified in 10CFRS0. This reference is to Footnote 9 of 10CFR50.55a which specifies that Regulatory Guide 1.26 and Section of NUREG-0800 may be used for this purpose. Section of NUREG-0800 allows the use of either the NRC Group Classification system of Regulatory' Guide 1.26 or the ANS Safety Classification system (referring to the method described in ANSI/ANS-51.1 and ) which can be cross-referenced to Regulatory Guide The Section XI Boundary Classification Process

6 The classification of systems and components is a two-phase process: first, classification is performed based on system/component function. After this initial "bounding" process, the included components are evaluated for the application of ASME Section XI requirements and exemptions. A review is performed to identify systems, or portions or systems, which may be considered safety-related. The conclusions of this review, and their bases, should be documented. This documentation should include discussion of systems and components that are outside the scope of Section XI. However, augmented examinations and tests should be performed for systems and components outside the scope of Section XI commensurate with the safety functions of these systems and their components. For the systems that were identified to be safety-related and within the scope of Section XI, the components of these systems are then evaluated, based on the system safety function(s) identified, per the classification documents listed previously. These components are then identified accordingly as ASME Class 1, ASME Class 2, ASME Class 3, or non-class. When a particular group of components has been identified as performing an ASME Class 1, 2, or 3 function, the components should be further reviewed to assure that the boundary interfaces (boundary valves and barriers) meet the criteria of 10CFR50.2, 10CFR50.55a(c)(2), RG 1.26, SRP 3.2.2, or ANSI/ANS or Technical positions should be written to detail any deviations from the boundary classification criteria of these classification documents. These technical positions should be included in an appendix of the classification basis document. When the safety function(s) and boundary interfaces are determined for a system, the Section XI boundaries are marked on the applicable flow diagrams or P&IDs, typically with "flags" containing characters designating Section XI Code Class 1, 2, 3 or non-class (NC). Classification Notes Section XI boundaries for Class I systems are typically established per 10CFR50.2 which requires that the reactor coolant (Class 1) pressure boundary extend to include: (l) the outermost containment isolation valve in system piping which penetrates the primary reactor containment, (2) the second of two valves normally closed during normal reactor operation in system piping which does not penetrate primary reactor containment, (3) the reactor coolant system safety and relief valves and, for boiling water reactors, (4) the outermost containment isolation valve in the main steam and feedwater piping. Exception may be taken to these boundary, criteria for Class 1 components, per 10CFR50.55a(c)(2), provided: (1) in the event of postulated failure of the component during normal reactor operation, the reactor can be shut down and cooled down in an orderly

7 manner assuming makeup is provided by the reactor coolant makeup system or, (2) the component is or can be isolated from the reactor coolant system by two valves in series (both closed, both open, or one closed and the other open). However, each open valve must be capable of automatic actuation and, assuming the other valve is open, its closure time must be such that, in the event of postulated failure of the component during normal reactor operation, each valve remains operable and the reactor can be shutdown and cooled down in an orderly manner, assuming makeup is provided by the reactor coolant makeup system only. Section XI boundaries for Class 2 and 3 systems are typically established per RG 1.26, footnote 4, which stipulates that the boundary include those portions of the system required to accomplish the specified safety function and the connecting piping up to and including the first valve that is either normally closed or capable of automatic closure when the safety function is required. In the event that a system performs more than one function, each of which is a different class, the higher class would apply to all components. Note that for the purposes of this classification process, in most cases, Quality Group A (RG 1.26) and Safety Class 1 (ANSI/ANS-52.1) are considered equivalent to Section XI Class 1; Quality Group B (RG 1.26) and Safety Class 2 (ANSI/ANS-52.1) are considered equivalent to Section XI Class 2; and Quality Group C (RG 1.26) and Safety Class 3 (ANSI/ANS-52.1) are considered equivalent to Section XI Class 3. Any exceptions to this convention should be documented. Optional construction of a system, or a component within a system boundary, to a classification higher than the minimum class established in the component design specification (either upgrading from Class 2 to Class 1 or from Class 3 to Class 2) does not affect the overall system classification by which the rules for examination and testing are determined. Application of ASME Classifications The second phase of the ASME boundary classification process is the application of the examination requirements of ASME Section XI, detailed in paragraphs IWB-1210, IWC-1210, IWD-1210, and IWF-1210; the application of the exemptions of ASME Section XI, detailed in paragraphs IWB-1220, IWC- 1220, IWD-1220, and IWF-1230; and the testing requirements identified in ASME Section XI, Subsections IWV and IWP, or the O&M Code, as applicable. The basic rule for application of ASME Section XI examination requirements to components included in the Section XI boundaries per Section 3.2 is given in paragraph IWA-1320: For ASME Class 1 components (Quality Group A), the requirements of Subsection IWB apply; for ASME Class 2 components (Quality Group B)

8 the requirements of Subsection IWC apply; and for ASME Class 3 (Quality Group C) components the rules of Subsection IWD apply. For IST, the testing requirements for all Code Class components are determined by component type and safety function, with the exception that closure testing of certain valves may be required due to their location as Code Class pressure boundary isolation valves. **The above information was extracted from the training classes given by True North (BCP) in recent years. In addition, further guidance is provided in NUREG-1482 and the NRC Workshop Summary, regarding the classification of components/systems for ISI and IST. Care must be taken to ensure that components which are not tested under the IST Program are tested "commensurate with the safety significance of the components." This is to satisfy 10 CFR 50 Appendix B requirements.