ASTM D7491-21

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Designation: D7491 − 08 (Reapproved 2015) D7491 − 21
Standard Guide for
Management of Non-Conforming Coatings in Coating
Service Level I Areas of Nuclear Power Plants
This standard is issued under the fixed designation D7491; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This guide provides the user with guidance on developing a program for managing non-conforming coatings in Coating
Service Level I areas of a nuclear power plant.
1.2 Non-conforming coatings include degraded previously DBA-qualified qualified or acceptable coatings, unqualified coatings,
unknown coatings, and unacceptable coatings.
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
D4538 Terminology Relating to Protective Coating and Lining Work for Power Generation Facilities
2.2 Other Documents:
Regulatory Guide 1.54 Revision 0, Quality Assurance Requirements for Protective Coatings Applied to Water-Cooled Nuclear
Power Plants
Regulatory Guide 1.54 Revision 1, Service Level I, II, and III protectiveProtective Coatings Applied to Nuclear Power Plants
Regulatory Guide 1.54 Revision 2, Service Level I, II, and III Protective Coatings Applied to Nuclear Power Plants
Regulatory Guide 1.54 Revision 3, Service Level I, II, and III and In-Scope License Renewal Protective Coatings Applied to
Nuclear Power Plants
EPRI Report 10031021019157 Plant Support Engineering: Guideline on Nuclear Safety-Related Coatings, Revision 1 (formerly
TR-109937)2 (formerly TR109937 and 1003102)
3. Terminology
3.1 Definitions—Definitions for use with this guide are shown in Terminology D4538 or other applicable standards.
This guide is under the jurisdiction of ASTM Committee D33 on Protective Coating and Lining Work for Power Generation Facilities and is the direct responsibility
of Subcommittee D33.10 on Protective Coatings Maintenance Work for Power Generation Facilities.
Current edition approved Dec. 1, 2015Feb. 1, 2021. Published January 2016February 2021. Originally approved in 2008. Last previous edition approved in 20082015 as
D7491D7491 – 08 (2015). – 08. DOI: 10.1520/D7491-08R15.10.1520/D7491-21.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from U. S. Nuclear Regulatory Commission, Distribution Services Section, Washington, DC 20555–0001, http://www.nrc.gov.
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D7491 − 21
3.2 Definitions of Terms Specific to This Standard:
3.2.1 non-conforming coatings, n—a coating or coating system in a Coating Service Level I application that lacks or has
insufficient documentation to support or verify DBA qualification.
3.2.1.1 Discussion—
This would include coatings referred to as unqualified, unacceptable, and degraded qualified coatings.
3.2.2 unacceptable coating system, n—A safety related coating system for which no suitability for application review which meets
the plant licensing requirements has been completed.
3.2.2.1 Discussion—
Therefore, no reasonable assurance exists that, when properly applied and maintained, the coating or lining will not detach under
normal or accident conditions. This is applicable to “pre-ANSI” plants.
4. Summary of Practice
4.1 The process and use of this guide is summarized in
Fig. 1.
5. Significance and Use
5.1 There are several methods for managing non-conforming coatings in an operating nuclear power plant. This guide outlines
methods that have been determined to be acceptable to the nuclear industry.
5.2 Managing the amount of non-conforming coatings is key to ensuring the amount assumed, in the licensing bases is not
exceeded.
5.3 EPRI Report 1003102 Revision 1 (formerly TR-109937) 1019157 provides additional information on the selection,
application, inspection and maintenance of nuclear plant safety-related protective coatings. This reference offers a detailed
discussion of important considerations related to protective coatings and can be used to supplement this guide as deemed necessary.
6. Establishing the Design Limit of Non-Conforming Coatings
6.1 Determine what coatings do not meet the licensing basis for the plant. For plants that have commitments to meet Regulatory
Guide 1.54 (applicable revision) and/oror related ANSI/ASTM standards standards, or both, typically require DBA testing of
coatings and extensive documentation associated with the application of the qualified coatings. This may be a more significant
requirement to satisfy than for an older plant which has not made commitments to these requirements.
6.2 The key to ensuring plant safety is to manage the amount of non-conforming coatings so that it does not exceed the amount
assumed in calculations that support plant operation, such as sump suction strainer head loss.
6.3 Managing non-conforming coatings, must consider the capacity of the Emergency Core Cooling System (ECCS) suction
strainer to accommodate debris expected to reach the ECCS suction strainer (including coating debris) without reducing the overall
ECCS pump net positive suction head (NPSH) margin below an acceptable value. Those plants with significant operational NPSH
margin for accommodating additional debris may require less precision when determining the amount of non-conforming coatings;
simplified bounding techniques may be sufficient.
6.4 The non-conforming condition may also affect other plant design and licensing limits, such as coating thickness affects on the
accident heat transfer and peak temperature calculations, and Fire Hazards Analysis.
7. Determining the Amount of Non-Conforming Coatings
7.1 Essentially every plant has some amount of non-conforming coatings inside of primary containment and this may be an
acceptable condition. There are two considerations when identifying non-conforming coatings.
7.1.1 Does the coating meet the licensing basis commitments?
7.1.2 Is there reasonable assurance the coating will not detach during normal operation or a Design Basis Accident (DBA)?
D7491 − 21
FIG. 1 Managing Non-Conforming Coatings
D7491 − 21
7.2 The amount of coating that was applied inconsistent with licensing commitments and design requirements needs to be
identified.
7.3 It may also be appropriate to review procurement documents (including records of work performed ) for equipment installed
in containment to determine if coating applications performed off site conforms to licensing bases and design requirements.
7.4 If records cannot be found that identify the types and quantities of coatings (for example, weight or volume) installed in
containment, then some area, thickness, and density estimations need to be performed.
7.5 The results of the investigation should be tabulated according to the various containment surfaces, indicating the type, quantity,
location, and qualification classification of the coating applied. Photographic documentation is also helpful for reference to the
findings.
7.6 The tabulation should also consider identification of the complete coating system as applied.
7.7 Periodic reassessment or establishing a new baseline should be considered.
8. Guidance on Managing Non-Conforming Coatings
8.1 Once an accounting of the amount of non-conforming coatings is determined, a decision will need to be made as to how to
manage the results. It is important to know the reason a particular area of coating
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