ContentsTable of contents
3.0 Health monitoring 13
6.0 Aov references 21
Scope and purpose
3.0 Health monitoring
4.0 Effective program assessment
6.0 Aov references
Joint Owners Group Air-Operated Valve Program
Review of Air-Operated Valve Related Event
Analysis of Events That Involved Active Air-Operated Valves (AOVs) (issued April 2010)
Failure of Air Operated Valve to Operate
Air-Operated Valve Performance
Conducting Preventive Maintenance on Air Operated Valves
Experiences and Attributes of Successful Valve Teams, Dec. 2000
Guidelines for the Selection and Application of Power Plant Control Valves
Air Operated Valve Evaluation Guide
A Study of Air-Operated Valves in U.S. Nuclear Power Plants
Resolution of Generic Safety Issue 158: Performance of Safety-Related Power-Operated Valves Under Design Basis Conditions
AOV Program Interview Questions
ENGINEERING PROGRAM GUIDE
June 2011 Update
Institute of Nuclear Power Operations
This good practice was originally developed in 2007 to consolidate industry experience pertaining to successful oversight and implementation of key engineering activities. Representatives of utilities participating in engineering program working group meetings sponsored by INPO provided significant input for this good practice.
It is recognized that other methods for achieving excellence in the implementation of an Air-Operated Valve (AOV) Program exist and may be equally effective. Accordingly, this good practice is offered as a guide to assist member utilities desiring to improve their programs or methods. Member utilities are not obligated to adopt all parts of this good practice. Rather, utilities should consider the information contained herein and selectively use appropriate information for developing or improving their programs or methods.
This document describes the attributes associated with AOVs as if they are managed as an engineering program. It is recognized that activities controlled as an engineering program at one site may be managed as a process at another. The approach chosen at a plant site should be based on the particular organization structure, the oversight methods, and the perceived need for programmatic controls to improve or sustain good performance. This document provides a framework to guide development, assessment, and improvement of program implementation and should be applied with careful consideration of the respective station’s expectations, limitations, and situation.
2011 Update: This document has been updated to incorporate new references since 2007, user feedback, improved layout, recent industry lessons learned, and better grouping of sample assessment questions. Any examples in this report are provided for illustrative purposes only, and variation among the utilities with regard to the information is expected.
For additional information or to provide feedback to improve the usefulness of this good practice, contact the INPO manager, Engineering and Configuration Management, at (770) 644 8000 or via the INPO member Web site.
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Section Title Page
1.0SCOPE AND PURPOSE 1
2.0 ATTRIBUTES 1
2.1 Program Structure 2
2.2 Program Staffing and Experience 7
2.3 Program Implementation 9
3.1 Health Criteria 13
3.2 Health Rating 15
3.3 Leading Indicators of Effectiveness 15
4.0 EFFECTIVE PROGRAM ASSESSMENT 16
4.1 Conduct of Program Assessment 17
4.2 Program Assessment Techniques 19
5.0 OVERSIGHT 19
Appendix A AOV Program Interview Questions
Appendix B Precursors to Declining AOV Program Performance
Appendix C Operating Experience
Appendix D Assessment Planning Checklist
Appendix E Suggested Balance-of-Plant (BOP) AOV Focus Areas
Appendix F Example AOV Program Health Report
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This guide was developed to consolidate industry experience pertaining to successful oversight and implementation of activities that specify, monitor, and maintain the performance of air-operated valves. An Air-Operated Valve (AOV) Program encompasses activities associated with design verification, evaluation, testing, preventive maintenance, and surveillance of air-operated valves. The intent of an AOV Program is to provide assurance that AOVs with safety significance or importance to plant reliability and/or thermal performance are capable of performing their intended functions. See Appendix E for a discussion of Balance-of-Plant (BOP) AOVs focus areas.
This Engineering Program Guide (EPG) describes the main features of an AOV Program and the respective roles and responsibilities in typical nuclear power plant organizations. The AOV Program described in this document is based on the recommendations contained in the following documents:
In addition to these source documents, utilities should consider information and recommendations provided by operating experience, recognized industry forums such as the Air-Operated Valve Users Group (AUG), EPRI technical guidance documents, and NRC Information Notices when developing or assessing their AOV Program.
This document is intended to be applied as a reference for self-assessments, program improvement initiatives, and plant evaluation preparations. It should not be considered as a prescriptive standard. Utilities should selectively use the most appropriate information to improve performance. This document outlines organizational and programmatic attributes and does not contain guidance on the technical methods used to establish program scope, design verification, or testing.
Effective engineering programs share many common attributes. This program guide discusses attributes associated with program infrastructure, including roles and responsibilities; staffing and experience levels necessary to conduct program activities; and steps associated with effective implementation.
Without sufficient infrastructure, the program will lack the integration, organization, and support necessary to be effective. A systematic approach to managing AOV activities is more likely to ensure success. However, even a well-developed process will fail if those responsible for program implementation lack the necessary skills and knowledge, do not understand the program basis and objectives, or do not follow program requirements rigorously. Industry experience with AOV programs indicates that the majority of program implementation problems can be traced to one or more of the following causes: turnover of key personnel, poor communication between stakeholders, insufficient review of operating experience, and lack of experience or knowledge of program requirements. Program implementation is best assessed by teams that include external peers or AOV experts with knowledge of program implementation problems in the industry.
The infrastructure of an effective Air-Operated Valve (AOV) Program ensures an organizational framework that facilitates proper integration of program activities. The structure is detailed in a program description, program plan, policy, procedure, or process description. The following basic elements should be present in any program addressing AOVs:
Roles and responsibilities and handoffs between organizations are clearly defined. They include the following:
220.127.116.11 The following summarizes responsibilities of organizations/personnel involved with the implementation of the AOV Program. Because of the different sizes and structures of utility organizations, the responsibilities listed below may be combined or further divided to fit the particular organization structure. However, experience has shown that it is important that the utility/plant designates responsibility for the overall ownership of the program. The duties of the program owner are listed below:
18.104.22.168 In addition to the primary stakeholders identified above, members of other groups provide inputs and perform activities essential to program implementation. These support functions are as follows:
2.1.3 Configuration Management
22.214.171.124 AOV Program Documents – Documentation (specifications, calculations, setpoints, and so forth) should comply with applicable industry guidance documents and with station and company standards. Documentation should be sufficient to ensure that the program is process-driven and not overly dependent on the knowledge of any one individual. The program documentation should enable efficient turnover of program personnel and training of backup personnel. The documentation typically consists of the following:
2.2 Program Staffing and Experience
Because of the different functional responsibilities, organizational structures and sizes, and staffing, the experience levels of individuals involved in the AOV Program may vary. However, it is important for program responsibilities to be assigned to individuals with qualifications generally in line with the following implementation.
2.2.1 Typical Qualifications
The development and maintenance of a strong AOV Program is directly dependent on the expertise, knowledge, and background of those personnel assigned program responsibilities. In some of the positions, the skill sets and knowledge requirements are highly specialized. The following descriptions outline the recommended training and experience for the key positions in the AOV Program.
126.96.36.199 AOV Program Manager/AOV Engineer
188.8.131.52 AOV Coordinator/Maintenance Lead
2.2.2 Typical Site-Specific Training
184.108.40.206 Typical Engineering AOV-Specific Training
220.127.116.11 Typical Maintenance & Planning AOV-Specific Training
Maintenance personnel involved in AOV maintenance and diagnostic testing are trained or retrained, as applicable to their duties, before beginning field work. Training includes, but is not limited to, the following:
2.2.4 Industry Involvement
Understanding of current industry experience and timely, effective incorporation of lessons learned are essential for maintaining excellence in AOV Program performance. Consider participation in the following industry wide events/organizations:
2.3 Program Implementation
The activities highlighted below are instrumental in AOV Program implementation. They encompass all essential Joint Owners Group (JOG) program elements and how they can be sequenced effectively for program implementation.
Program implementation activities can be categorized into two distinct phases: initial program development (one-time activities) and program maintenance.
Activities in the program implementation phase are as follows:
Activities in the program maintenance phase are as follows:
2.3.1 Program Implementation Phase
Several of the program implementation activities are interrelated; as such, they are implemented most effectively if performed in sequence.
The following sequencing is recommended for the program implementation phase:
Training is provided to support the implementation sequence. Early engineering training would be most desired prior to development of scoping and categorization. Training for diagnostic testing should closely follow with actual field testing experience so that knowledge is retained and proficiency is developed. Acquiring field experience on balance-of-plant AOVs, then moving into baseline testing of category 1 or 2 valves, is an effective approach.
Based on the population of valves and the number of activities, a detailed implementation schedule is warranted. The schedule should contain the following level of detail:
The program implementation phase may require supplemental resources to implement several milestones. It may not be reasonable to expect existing staffing to be able to support program implementation within a reasonable time frame. Many facilities have used supplemental personnel to perform one-time tasks such as calculations, setpoint establishment, and PM development.
An integrated, staged approach is most efficient for timely program implementation. Categorization, DBRs, setpoint determination, and then baseline testing is performed sequentially for valve groups of a manageable size. For example, attempting to complete all DBRs prior to moving forward with setpoint determination is not recommended as it prolongs overall program implementation.
2.3.2 Program Maintenance Phase
After the program is established, there is a transition to the program maintenance phase. The intent is for program activities to be automatically scheduled or completed as a result of normal station processes.
Periodic testing and time-based preventive maintenance activities are scheduled automatically via the station PM program.
When conducting periodic testing to determine AOV condition, it is prudent to plan contingency work packages to repair any degraded components identified during testing. This enables proper resolution of degraded conditions encountered during the testing. By having work packages, parts, and resources on hand when diagnostic testing is performed, the station can respond quickly to any emergent issues noted from the testing.
Engineering procedures, configuration management procedures, PM procedures, and administrative procedures are in place to ensure required changes are accomplished as a normal station practice. Changes affecting program AOVs should be process-driven and should not require the specific knowledge or direct intervention of the program owners. However, there should be established feedback mechanisms to ensure that AOV program requirements are maintained. Some sources of feedback are as follows:
Processes to Maintain Configuration – Plant procedures should be in place to maintain configuration of associated AOVs and documentation.
3.1 Health Criteria
Quantitative performance measures are used to gauge the health of the AOV Program, identify degrading trends and programmatic gaps, encourage continuous improvement, and monitor effectiveness of support processes. The performance measures provide evidence of the material condition and health of AOVs within the AOV Program scope. Examples of performance measures that should be included are preventive maintenance, valve failures, training qualifications, thermal performance, and regulatory issues. In addition, compliance to program schedule commitments and use of self-assessments to improve program effectiveness should be monitored. Periodic program health reports or other methods may be used to communicate performance measures. For an example of a good AOV Program Health Report, see Appendix F.
Sources for quantitative performance measures may include the following:
3.2 Health Rating
3.2.1 Target Values
Numeric target values and ranges should be established to provide objective and consistent bases for rating AOV program effectiveness. The indicators should encompass regulatory issues, equipment reliability, personnel training, operating experience, and continual improvement initiatives.
Ranges conventionally correspond to colors from green to red, depicting excellent to unacceptable performance. When setting target values, (a) include a provision for periodic review of the target values, so as to encourage continuous improvement; and (b) consider benchmarking when possible to ensure utility-specific criteria are consistent with accepted industry norms for standards of performance.
3.2.2 Overall Health Rating
Once individual performance criteria and targets are established, a method should be established to determine an overall health rating for the program. Weighting factors based on relative importance of each individual performance measure (or attribute) may be used, in a computational method, to determine the overall health rating. This approach lends both objectivity and consistency to ratings, which are particularly important for larger utilities when rolling up the results across a number of plants.
In addition to the health rating, an overall trend should be included to determine whether program health has an improving or degrading tendency over the last several reporting periods.
3.2.3 Action Plans
AOV health monitoring should drive action. Program health reports should include specific action plans for improvement when performance falls below acceptable levels. The program description should include documented guidance for when action plans are warranted based on objective determination of health and trend. For example, some stations require a documented improvement plan when program health is red or yellow and on a declining trend. The action plan should specify accountability for each action, expected completion dates, and a current status that addresses roadblocks and support needed by the action owner. For indicators that are at acceptable levels, some stations use action plans to achieve green.
3.3 Leading Indicators of Effectiveness
To the extent possible, system health reports should include leading indicators that identify precursors to declining program performance. A number of precursors to declining program performance are included in Appendix B. Some examples of leading indicators are:
The purpose of an assessment is to provide an objective critique of station program performance. Using constructive industry feedback, assessments can identify program deficiencies, strengths, and enhancement opportunities. Furthermore, an assessment offers a means of continual improvement and prioritization of upcoming program activities.
This section provides supplemental guidance for AOV Program assessments with the assumption that utility-specific procedures and processes for the general conduct of self assessments already exist. While the other sections of this document provide guidance on establishing program scope, attributes, health monitoring, and management oversight, this section focuses on how to verify whether those elements exist and if they are being implemented effectively.
Some aspects of the AOV Program require specific technical knowledge or expertise for proper evaluation. Therefore, it is essential to obtain outside expertise from other stations, industry organizations, INPO, vendors, or consulting firms to bring independent scrutiny to the self-assessment.
4.1 Conduct of Program Assessment
AOV Program assessments should be conducted in accordance with existing station processes or procedures. Typically, stations require an assessment at least once every three years. During the course of an overall program assessment, suggested functional areas to review are as follows:
4.1.1 Suggested Focus Areas for the Assessment:
4.1.2 Suggested Documents to Review:
4.1.3 Suggested Personnel to be Interviewed (listed by job function)
Sample interview questions are included in Appendix A.
4.2 Program Assessment Techniques
For assessment techniques, consult the station’s administrative procedure for self-assessments as well as other industry standards such as INPO Principles for Effective Self-Assessment and Corrective Action Programs, December 1999.
In addition to the station-specific guidance for conducting assessments, an assessment planning checklist is provided in Appendix D to facilitate logistical elements of the assessment.
Effective oversight requires management ownership and engagement in reviewing, sustaining, supporting, and improving the health of the AOV Program. To have appropriate oversight, station management must ensure the AOV Program has a clear owner and the program owner has the required technical and administrative skills necessary to manage the AOV Program. Management must require and provide periodic feedback in support of the AOV Program. In addition, managers must provide the resources necessary to affect programmatic and equipment reliability improvements.
Station management is responsible for maintaining the appropriate level of oversight for the AOV Program. The AOV Program owner is responsible for ensuring station management is informed about AOV issues and programmatic needs. Both aspects are necessary for maintaining an effective AOV Program.
The following are examples of management actions necessary to support and provide oversight of the AOV Program. The absence of any of these actions creates a potential gap in management oversight.
5.1 Program Review Committees
Program review committees provide a periodic forum for engineering program owners to status program effectiveness with station management. These forums can be presented as part of another station committee, such as a Plant Health Committee, and should be used by management to challenge program performance, develop program consistency, and ensure that improvement issues are sponsored with timely corrective actions.
For large utilities or regional information sharing groups, the AOV Program owners from the multiple stations may serve as the review committee members. For these cases, feedback and communication to station management on a periodic basis is an important element in overall program health monitoring.
Routine supervisor and management observations of program activities including testing, inspections, and disposition of operating experience and corrective actions can gauge program effectiveness and provide feedback to program owners.
AOV Program owners and/or key individuals are actively involved in industry users groups, working committees, assessments, and benchmarking. Experience gained from such industry involvement is incorporated into the AOV Program.
INPO references, AOV-related operating experience, and the AOV Forum can be obtained from the INPO Air-Operated Valve Web page, under Maintenance Focus Areas/Valves on the INPO home page at http://www.inpo.org.
Joint Owners Group AOV Program Document
INPO NX-1018, Revision 1, ^
INPO Topical Reports & Analysis Digests
TR4-41, Review of Main Feedwater (MFW) System Related Events (issued July 2004)
TR4-41, Addendum 1: Review of Main Feedwater (MFW) System Related Events (issued September 2006)
TR4-42, ^ s (issued December 2004)
TR4-42, Addendum 1: Review of Air-Operated Valve Related Events (2000 Through September 2006), (issued December 2006)
AD 2009-02, Analysis of Events That Involve Active Air-Operated Valves (AOVs) (issued March 2009)
AD 2010-01, ^
Email from David F. Garchow (INPO VP, Plant Technical Support): Lessons Learned & Recommendations from INPO AOV Assist Visits (issued October 21, 2010), posted on http://www.aovusersgroup.com in the Industry Documents section
Industry Action Plan: AOVs as an INPO Important Issues List Item, November 2009, posted on http://www.aovusersgroup.com in the Industry Documents section
INPO Significant Event Reports
SER 4-84, ^
SER 5-92, Power Operated Relief Valve Failures Caused by Improper Installation of Actuator Diaphragm
SER 4-93, Reactor Coolant Pressure Transients Caused by Failed Open Pressurizer Spray Valves
SER 3-95, Undetected Emergency Feedwater Valve Leakage
SER 1-99, ^
INPO Significant Operating Experience Reports
SOER 82-9, Turbine Generator Exciter Explosion
SOER 88-1, Instrument Air System Failures
SOER 90-1, Ground Faults on AC Electrical Distribution Systems
SOER 95-1, Reducing Events Resulting from Foreign Material Intrusion
SOER 99-1 and Addendum, Loss of Grid
INPO Operations & Maintenance Reminders
O&MR 394, Component Failures Associated with Main Feedwater Control Systems
O&MR 405, Air-Operated Valve Settings for Containment Isolation and Reactor Coolant Boundary Isolation Functions
O&MR 412, ^
O&MR 419, Improving the Reliability of Fisher Model 546 I/P Converters
NP-5697, Valve Stem Packing Improvements, May 1988
NP-7079, Instrument Air Systems – A Guide for Power Plant Maintenance Personnel, Dec. 1990
NP-7412-R1, Air Operated Valve Maintenance Guide
TR-1003091, Valve Positioner Principles and Maintenance Guide
TR-1003472, Level Control Guide for Feedwater Heaters, Moisture Separator/Reheaters and Other Equipment
TR-1007915, Solenoid Valve Maintenance Guide
TR-105852V1, Valve Application, Maintenance, and Repair Guide, February 1999
TR-106857-V1 & 2000 Addendum, Preventive Maintenance Basis Volume 1: Air Operated Valves
TR-107321, Application Guide for Evaluation of Actuator Output Capability for Air-Operated Valves in Nuclear Power Plants
INPO Letter dated April 18, 1997 to the industry on air-operated valve issues from Manager, Engineering Support Department
PPM Software Error Notice 2004-2, Potential Non-Conservatism in Butterfly Valve Model Predictions Under Compressible Flow Conditions
NUREG/CR-6654, ^ , February 2000
NUREG-1275, Evaluation of Air-Operated Valves at U.S. Light-Water Reactors
NRC Generic Letter 95-07, Pressure Locking and Thermal Binding of Safety-Related Power Operated Gate Valves
NRC Generic Letter 96-06, Assurance of Equipment Operability and Containment Integrity During Design
NRC RIS 2000-03, ^
NRC IN 2006-15, Vibration-Induced Degradation and Failure of Safety-Related Valves
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