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Regulatory document RD/GD-210, Maintenance Programs for Nuclear Power Plants sets out the requirements of the Canadian Nuclear Safety Commission (CNSC) with regard to maintenance programs for nuclear power plants (NPPs). An NPP maintenance program consists of policies, processes and procedures that provide direction for maintaining structures, systems or components (SSCs) of the plant.
Effective maintenance is essential for the safe operation of a nuclear power plant. The range of maintenance activities includes monitoring, inspection, testing, assessment, calibration, service, overhaul, repair and replacement of parts. The scope of the maintenance program covers all structures, systems or components (SSCs) within the bounds of the nuclear power plant. The type and frequency of maintenance activity applied to each SSC are understood to be commensurate with the SSC’s importance to safety, design function and required performance.
This document also provides information and guidance on how the requirements may be met.
The majority of maintenance activities are traditionally allocated to the concept of preventive maintenance. These maintenance activities can be derived, for example, from design or reliability requirements, codes and standards, and operating experience and are performed on the basis of service time, actual condition or predicted condition. Where the performance or condition of an SSC does not allow it to function as per design, corrective action must be taken.
The results of all maintenance activities are fed back through an optimization process that enables continuous improvement of the program.
The requirements outlined in this regulatory document are consistent with international guidelines, including Safety Related Maintenance in the Framework of the Reliability Centered Maintenance Concept, TECDOC-658, and Maintenance, Surveillance and In-service Inspection in Nuclear Power Plants, Safety Standards Series, No. NS-G-2.6, both from the International Atomic Energy Agency (IAEA).
It is not the intent of this regulatory document to override requirements provided by other codes and standards but rather to provide the framework within which such codes and standards are applied to ensure that SSCs function as per design.
When incorporated into a licence or other legally enforceable instrument, this regulatory document becomes a legal requirement.
In this document, “shall” is used to express a requirement, i.e., a provision that a licensee or licence applicant is obliged to satisfy in order to comply with this regulatory document. “Should” is used to express guidance, or that which is advised but not required. “May” is used to express an option or that which is permissible within the limits of this regulatory document. “Can” is used to express possibility or capability.
1.0 Introduction
1.1 Purpose
1.2 Scope
1.3 Relevant regulations
1.4 National and international standards
2.0 Background
3.0 Elements in the Maintenance Program
3.1 Element One: Program Basis
3.1.1 Requirements for Program Basis
3.1.2 Guidance for Program Basis
3.2 Element Two: Maintenance Organization
3.2.1 General requirements for maintenance organization
3.2.2 Organizational structure
3.2.3 Policies, processes and procedures
3.2.4 Training and qualification of workers
3.2.5 Maintenance facilities
3.2.6 Contract workers
3.3 Element Three: Maintenance Activities
3.3.1 General requirements for maintenance activities
3.3.2 General guidance for maintenance activities
3.3.3 Preventive maintenance
3.3.4 Corrective maintenance
3.3.5 Aging management
3.3.6 Activity optimization
3.4 Element Four: SSC Monitoring
3.4.1 General requirements for SSC monitoring
3.4.2 General guidance for SSC monitoring
3.4.3 Condition monitoring
3.4.4 Surveillance
3.4.5 Testing
3.5 Element Five: Maintenance Work
3.5.1 General requirements for maintenance work
3.5.2 General guidance for maintenance work
3.5.3 Work assessment
3.5.4 Work planning and scheduling
3.5.5 Outage management
3.5.6 Maintenance procedures
3.5.7 Post-maintenance verification and testing
3.6 Element Six: Spare Parts and Procurement
3.6.1 Requirements for spare parts and procurement
3.6.2 Guidance for spare parts and procurement
3.7 Element Seven: Management Assessment and Program Review
3.7.1 Requirements for management assessment and program review
3.7.2 Guidance for management assessment and program review
3.8 Element Eight: Record Keeping
3.8.1 Requirements for record keeping
3.8.2 Guidance for record keeping
Glossary
References
Additional Information
This regulatory document sets out the requirements of the Canadian Nuclear Safety Commission (CNSC) with regard to maintenance programs for nuclear power plants (NPPs). This document also provides information and guidance on how the requirements may be met.
An NPP maintenance program consists of policies, processes and procedures that provide direction for maintaining structures, systems or components (SSCs) of the plant.
Effective maintenance is essential for the safe operation of a nuclear power plant. The range of maintenance activities includes monitoring, inspection, testing, assessment, calibration, service, overhaul, repair and replacement of parts. The scope of the maintenance program covers all structures, systems or components (SSCs) within the bounds of the nuclear power plant.
The following provisions of the Nuclear Safety and Control Act (NSCA, the Act) and regulations made under the NSCA are relevant to this regulatory document:
This regulatory document is consistent with modern national and international guides and standards for maintenance programs for NPPs. In particular, this regulatory document is based in part on the following national and international publications:
Effective maintenance is essential for the safe operation of a nuclear power plant. The facility must be monitored, inspected, tested, assessed and maintained to ensure that SSCs function as per design. Various maintenance concepts can be used to form a maintenance strategy.
Figure 1 illustrates an example of the relationship of maintenance concepts and associated maintenance activities that provide the basis of a good maintenance strategy. This strategy would be supported by the maintenance program.
The majority of maintenance activities are traditionally allocated to the concept of preventive maintenance. These maintenance activities can be derived, for example, from the safety analysis assumptions, design or reliability requirements, codes and standards, and operating experience and are performed on the basis of service time, actual condition or predicted condition. Where the performance or condition of an SSC does not allow it to function as per design, corrective action must be taken.
The results of all maintenance activities are fed back through an optimization process which enables the continuous improvement of the program.
Figure 1: Relationship of maintenance concepts and activities
To ensure that the overall maintenance strategy is effective, the maintenance program must include mutually supporting elements. These elements cover program basis, maintenance organization, maintenance activities, system health monitoring, maintenance work, spare parts and procurement, management assessment and program review, and record keeping.
Each program element requires sufficient resources governed by the licensee’s approved policies, processes and procedures. These elements, when integrated, will form a comprehensive maintenance program.
Each program element is divided into objectives, where each objective is directly related to the requirements. For each objective a number of criteria have been established. The elements, objectives and associated criteria are described in sections 3.1 to 3.8, below.
The licensee shall define and follow a systematic approach to identify which maintenance activities are to be performed, on which SSCs, and at what intervals. The type and frequency of maintenance activity applied to each SSC is understood to be commensurate with the SSC’s importance to safety, design function and required performance.
The identification, selection and frequency of maintenance activities shall take the following into account:
Since the purpose of the maintenance program is to ensure that SSCs can function as per design, it follows that a maintenance strategy must have its basis in the approved plant design and safety analysis. Strategy development, therefore, requires a close liaison between the operating and design organizations to ensure that the strategy is based on a clear understanding of design philosophy and plant details.
The results of maintenance activities shall be used to provide feedback for program changes or design modifications. Program changes and design modifications shall be controlled in accordance with the licensee’s approved procedures and the maintenance program updated accordingly.
To ensure that a systematic approach is taken to identify which maintenance activities are to be performed, on which SSCs, and at what intervals, licensees should demonstrate that the following have been taken into account:
To demonstrate that the maintenance strategy has its basis in the approved plant design and safety analysis, and that all SSCs function as per design, licensees should demonstrate that the following criteria have been taken into account:
When using the results of maintenance activities to provide feedback for program changes or design modifications, licensees should demonstrate that the following criteria have been taken into account:
The licensee shall establish a maintenance organization to effectively implement the maintenance program.
Senior plant management shall be responsible for establishing and implementing the maintenance program. They shall establish clear lines of authority and define the responsibilities of the various managerial and supervisory positions.
Functions necessary to meet program element requirements may not traditionally be performed by groups within the maintenance department. In such cases, the interfaces between such groups shall be identified.
Engineering and technical support, with competence in all disciplines important for safety, shall be available throughout the lifetime of the plant.
Interfaces between trades groups and other work groups such as operations or radiation protection who interact with the maintenance organization shall be described.
When establishing and implementing the structure of the maintenance program, licensees should demonstrate that the following criteria have been taken into account:
When establishing interfacing statements, licensees should demonstrate that the following criteria have been taken into account:
When managing engineering and technical support, licensees should demonstrate that the following criteria have been taken into account:
When establishing interfaces between trades groups and other work groups who interact with the maintenance organization, licensees should demonstrate that the following criteria have been taken into account:
The licensee shall set out policies, processes and procedures that govern how the maintenance program is to be implemented.
The licensee shall ensure that the maintenance policies, processes and procedures are controlled, adhered to, and revised as necessary to reflect the current plant configuration.
The licensee shall have a process for ensuring that program documents are up-to-date.
When setting out policies, processes and procedures that govern how the maintenance program is to be implemented, licensees should demonstrate that the following criteria have been taken into account:
To ensure that the maintenance policies, processes and procedures are controlled, adhered to, and revised as necessary to reflect the current plant configuration, licensees should demonstrate that the following criteria have been taken into account:
When developing the process to ensure that program documents are up-to-date, licensees should demonstrate that the following criteria have been taken into account:
The maintenance program shall be supported by sufficient numbers of trained and qualified personnel. The adequacy of these resources shall be determined based on maintenance program objectives.
The details and results of the training program and personnel qualifications shall be documented. Personnel training and qualifications shall be kept up-to-date.
All maintenance personnel shall be given facility specific training in plant systems, work control, radiation protection, safety rules, access control, security and emergency procedures commensurate with their responsibilities.
Where applicable to their duties, maintenance personnel shall be trained and qualified with respect to other plant programs such as configuration management and quality assurance.
Prior to performing special jobs with higher risk to plant and personnel safety, maintenance personnel shall receive additional training commensurate with the activity ranging from a special job briefing up to full scale mock-up.
When determining the sufficient numbers of trained and qualified personnel to support the maintenance program, licensees should demonstrate that the following criteria have been taken into account:
When documenting training and qualifications for personnel (including contractors), licensees should demonstrate that the following criteria have been taken into account:
For facility-specific training of maintenance personnel, licensees should demonstrate that the following criteria have been taken into account:
For training of maintenance personnel on other plant programs, licensees should demonstrate that the following criteria have been taken into account:
For training of maintenance personnel on special jobs, licensees should demonstrate that the following criteria have been taken into account:
Maintenance facilities and work areas shall be provided including housing for the shipping, receiving, handling and storing of spare parts, tools and equipment. Where necessary, the facilities shall be access controlled and operated in a manner that preserves the correct environmental conditions and guards against hazards such as fire and chemical spills.
When preparing maintenance facilities and work areas, licensees should demonstrate that the following criteria have been taken into account:
The licensee shall ensure that contractors comply with work procedures and standards that are higher than or equal to those applicable to plant staff, particularly in the areas of professional competence, adherence to procedures and evaluation of performance. Suitable steps shall be taken to ensure that contract workers conform to equivalent technical standards of the operating organization.
The licensee shall be responsible for assuring the quality of contractor work. Processes shall be in place to control and verify activities performed by contract workers.
For contractor work, licensees should demonstrate that the following criteria have been taken into account:
For assuring the quality of contractor work, licensees should demonstrate that the following criteria have been taken into account:
The licensee shall include activities aimed at avoiding, detecting and repairing failures of SSCs.
As illustrated in Figure 1, maintenance activities aimed at avoiding and detecting incipient failures are considered preventive maintenance activities. Activities aimed at repairing failed SSCs are considered corrective maintenance activities. These activities can be combined at various levels to form a maintenance strategy to meet the program objectives.
Preventive maintenance activities are categorized as periodic (time-based), planned or predictive. Results from periodic or predictive activities may result in additional planned activities. These activities shall include accepted industry standards.
Time-based preventive maintenance should not be scheduled just prior to performance or functional testing as this may mask equipment degradation. However, if the conditions dictate, other preventive maintenance activities should be performed as appropriate.
For preventive maintenance activities, licensees should demonstrate that the following criteria have been taken into account:
When scheduling preventive maintenance activities, licensees should demonstrate that the following criteria have been taken into account:
The licensee shall have processes in place for initiating corrective maintenance and performing failure diagnosis of equipment. The processes shall include evaluating the impact of failed equipment and prioritizing the repair work with respect to ongoing maintenance activities.
The licensee shall have a process in place for controlling and performing temporary repairs including proper approvals, equivalency assessments and time period until the permanent repair can be implemented or an approved modification made.
For corrective maintenance activities, while keeping in mind that the processes include evaluating the impact of failed equipment and prioritizing the repair work with respect to ongoing maintenance activities, licensees should demonstrate that the following criteria have been taken into account:
When controlling and performing temporary repairs, licensees should demonstrate that the following criteria have been taken into account:
The licensee shall have a process to detect, assess, and manage deterioration of SSCs as a result of aging effects such as irradiation, corrosion, erosion, fatigue, and other material degradation. The type and frequency of maintenance activities shall be modified to accommodate such effects.
For more information on aging management programs (AMPs), refer to RD-334, Aging Management for Nuclear Power Plants [3].
A process shall be in place to optimize the maintenance activities based on results from items such as (but not limited to) the following:
When optimizing maintenance activities, licensees should demonstrate that the following criteria have been taken into account:
The licensee shall establish baseline criteria against which the function and performance of SSCs can be measured. These criteria shall include reliability, availability, function and performance requirements and assumptions used in the plant design and safety analysis.
The licensee shall include processes and procedures for evaluating whether or not SSCs continue to perform within the baseline criteria and for initiating corrective actions. These processes and procedures shall include condition monitoring, surveillance and testing.
When establishing baseline criteria for measuring the function and performance of SSCs (such as flow, pressure, temperature, amperage, etc.), licensees should demonstrate that the following factors have been taken into account:
As part of the processes and procedures for evaluating whether or not SSCs continue to perform within the baseline criteria and for initiating corrective actions, licensees should demonstrate that the following criteria have been taken into account:
The licensee shall have processes and procedures for carrying out condition monitoring. These consist of such things as periodic and in-service inspections, measurements or trending of SSC performance or physical characteristics to indicate current condition and future potential for failure. This monitoring is usually conducted on a non-intrusive basis and includes the use of specialized equipment. Vibration analysis, tribology and thermography are all examples of condition monitoring techniques.
SSCs performing standby functions shall have condition monitoring requirements that indicate operational readiness.
A process shall be in place to ensure that equipment qualification is maintained. Note that equipment qualification includes both environmental qualification and seismic qualification.
A process shall be implemented to ensure that all instrumentation remains within the calibration tolerances as required for it to perform as per design.
As part of the processes and procedures for carrying out condition monitoring, licensees should demonstrate that the following criteria have been taken into account:
When establishing SSC condition monitoring requirements, licensees should demonstrate that the following criteria have been taken into account:
As part of the process to ensure that equipment qualification (which includes environmental qualification and seismic qualification) is maintained, licensees should demonstrate that the following criteria have been taken into account:
As part of the process to ensure that instrumentation calibration is maintained, licensees should demonstrate that the following criteria have been taken into account:
The licensee shall have processes and procedures for carrying out SSC surveillance. Results shall be documented.
Examples of surveillance are process system configuration checks, system walkdowns, trending, sampling, operator rounds and routine readings.
As part of the processes and procedures for carrying out SSC surveillance, licensees should demonstrate that the following criteria have been taken into account:
The licensee shall have processes and procedures for performance and function testing to verify that SSCs are in good working order and are in a state of readiness to perform their functions. The licensee shall prepare test plans and such plans shall include the test frequency and acceptance criteria.
Instrumentation and test equipment used in performing the test program shall have the range and accuracy required to demonstrate that acceptance criteria have been met. All such test equipment shall be properly calibrated in accordance with a recognized national standard.
Where appropriate, the test program results shall be provided to the reliability program [1].
As part of the processes and procedures for performance and function testing, licensees should demonstrate that the following criteria have been taken into account:
The testing program should include a description of scope and responsibilities, scheduling mechanisms, test procedures, and methods for program updates.
For instrumentation and test equipment, licensees should demonstrate that the following criteria have been taken into account:
For test program results, licensees should demonstrate that the following criteria have been taken into account:
The licensee shall have processes and procedures for initiating, managing, assessing, prioritizing, planning and scheduling maintenance work. The resulting maintenance activity schedules shall be reviewed routinely and revised to account for changing conditions, operating experiences, and modifications.
The licensee shall undertake and accomplish maintenance activities in a manner that is commensurate with the safety significance of the SSC and with effective allocation of resources.
Unit and equipment identification shall be clear in work procedures and in the field to ensure that the proper equipment is isolated, maintained, and returned to service. Appropriate personal protection procedures shall be implemented before carrying out maintenance activities.
For the work management process, licensees should demonstrate that the following criteria have been taken into account:
To prioritize the maintenance activities, licensees should demonstrate that the following criteria have been taken into account:
To protect the safety of personnel, licensees should demonstrate that the following criteria have been taken into account:
The licensee shall implement a process for assessing maintenance activities. In addition to job tasks, the process shall assess the impact of maintenance activities on safety including such things as regulatory requirements, operating policies and principles, potential industrial and radiological hazards to site personnel, the public and the environment.
The assessment shall also take into account the cumulative effect of all plant equipment that is out of service on performance of safety functions.
(Note that “operating policies and principles” is standard Canadian terminology that is equivalent to the IAEA’s terminology of “operating limits and conditions”.)
As part of the process for assessing maintenance activities, licensees should demonstrate that the following criteria have been taken into account:
As part of the process for assessing the cumulative effect of out-of-service plant equipment on the performance of safety functions, licensees should demonstrate that the following criteria have been taken into account:
The licensee shall implement processes and procedures for planning and scheduling all maintenance activities. Work planning shall take place at the overall plant level and at the individual job level. Procedures to deal with any deferral or omission of a scheduled maintenance activity shall be included.
All maintenance personnel shall be made aware of the importance to safety of the tasks they are performing and of the potential safety consequences of technical or procedural errors. Clear equipment identification procedures shall be used.
Coordination of work groups shall be incorporated into work planning and scheduling. Where appropriate, pre- and post-job briefings shall be included.
A process for foreign material exclusion shall be implemented as appropriate for all maintenance work. This is particularly important when opening up closed systems such as process piping and mechanical equipment.
As part of the processes and procedures for planning and scheduling maintenance activities, licensees should demonstrate that the following criteria have been taken into account:
To address the potential safety consequences of technical or procedural errors, licensees should demonstrate that the following human performance tools have been taken into account:
When coordinating work groups, licensees should demonstrate that the following criteria have been taken into account:
The licensee should take into account the need to implement procedures for foreign material exclusion during maintenance activities.
The licensee shall have a process in place to appropriately manage the increased maintenance activities during plant outages. Effective work group coordination shall be established.
The plan to take equipment out of service for maintenance during an outage shall include measures to deal with all possible consequences of an event occurring while the equipment is out of service. This is particularly important when the equipment in question has a specific safety function or heat sink implication.
When planning and scheduling outage work, an assessment of the cumulative effect of all plant equipment that is out of service shall be undertaken to ensure no adverse effects on the performance of safety functions.
When managing outage activities, licensees should demonstrate that the following criteria have been taken into account, in addition to those in section 3.5.2:
When planning and performing maintenance on out-of-service equipment during plant outages, licensees should demonstrate that the following criteria have been taken into account:
When planning and scheduling outage work, licensees should demonstrate that the following criteria have been taken into account:
Maintenance shall be performed in accordance with approved written procedures, instructions or drawings as appropriate to the situation.
The licensee shall have a process in place for controlling procedure preparation, review, validation, issue, modification and revision. Where appropriate, acceptance criteria shall be defined and actions clearly specified in case acceptance criteria cannot be met.
When a procedure for carrying out a maintenance activity is found to be inadequate, there shall be measures to ensure that the activity is halted or safely managed until such time as the inadequacy in the procedure is corrected. If the inadequacy is not unique to the situation, a means of permanently correcting the procedure shall be provided.
Procedures shall include specific provisions when particular hazards are envisaged.
Temporary changes to procedures shall be properly controlled, be subject to review and licensee approval and specify the period over which the change is to apply.
Procedures shall be in place for the turnover of maintenance activities to relieving work crews.
Written procedures, instructions or drawings should demonstrate that the following criteria have been taken into account:
As part of the process for procedure control, licensees should demonstrate that the following criteria have been taken into account:
When a procedure is found to be inadequate, licensees should demonstrate that the following criteria have been taken into account:
When particular hazards are envisaged, licensees should demonstrate that the following criteria have been taken into account:
When applying temporary changes to procedures, licensees should demonstrate that the following criteria have been taken into account:
When turning over a procedure to another working group, licensees should demonstrate that the following criteria have been taken into account:
Before returning equipment to an operational state, the licensee shall ensure that post-maintenance verification has been completed, the affected configuration is verified, all relevant records are reviewed for completeness and any unexpected findings have been assessed and dispositioned. Where appropriate, post-maintenance testing shall be conducted and a fitness for service assessment shall be completed.
A process shall be in place to periodically assess that maintenance activities have been carried out within licensee expectations. This work shall be done by appropriately qualified individuals who do not have direct responsibility for performing the work. Assessment shall include direct observation of the specific maintenance activity as well as examination of the documentation.
Before returning equipment to an operational state, licensees should demonstrate that the following criteria have been taken into account:
As part of the process to periodically assess maintenance activities, licensees should demonstrate that the following criteria have been taken into account:
The licensee shall establish processes and procedures to procure, receive, store, secure and issue spare parts, tools and materials.
Authority for specifying technical and quality requirements shall be clearly defined when procuring spare parts. The spares shall meet the same technical standards and quality requirements as the installed plant items. The licensee shall have a change control process in place to deal with non-identical replacement parts and deviations from the original specifications.
Procurement processes shall include requirements for qualified suppliers. The receipt and acceptance procedures shall include a requirement to label, tag and quarantine items that are non-conforming.
Parts which have a limited lifetime shall be replaced accordingly. This is to ensure suitability for the expected service when needed. Defective parts which are not suitable for reuse shall be disposed of following a documented process to prevent reuse.
As part of the processes and procedures to procure, receive, store, secure and issue spare parts, tools and materials, licensees should demonstrate that the following criteria have been taken into account:
When procuring spare parts, licensees should demonstrate that the following criteria have been taken into account:
The licensee should ensure that qualified suppliers are identified according to applicable safety standards.
When replacing parts that have a limited lifetime, licensees should demonstrate that the following criteria have been taken into account:
The licensee shall establish a continuous process for assessment, review and improvement of the maintenance program to ensure that the maintenance strategy is effective, meets its objectives and has been implemented in accordance with applicable industry codes and standards.
Whenever a maintenance program deficiency is identified, its significance shall be assessed and where appropriate a cause determination shall be conducted and corrective actions taken. All reviews and assessments shall be properly documented and recorded.
Feedback from the improvement process shall be incorporated into the maintenance training program.
When establishing a continuous process for assessment, review and improvement of the maintenance program, licensees should demonstrate that the following criteria have been taken into account:
Licensees are required to have a process in place for dispositioning maintenance program deficiencies. Whenever a maintenance program deficiency is identified, licensees should demonstrate that the following criteria have been taken into account:
When incorporating feedback from the improvement process, licensees should demonstrate that the following criteria have been taken into account:
In addition to complying with the NSCA, regulations, and any other reporting and record-keeping requirements (such as CNSC regulatory document RD-99.1, Reporting Requirements for Operating Nuclear Power Plants [4]), the records and reports shall include sufficient information to provide objective evidence that the maintenance program is being fully implemented and in accordance with the quality assurance program.
The licensee shall document a description of repairs carried out, identifying the component that failed, the cause of failure, the remedial action taken, and the state of the system after repairs. The licensee shall periodically review the maintenance results for evidence of incipient or recurring failures.
To comply with reporting and record-keeping requirements, licensees should clearly define which records have to be kept, and these records should provide objective evidence that the maintenance program is being effectively implemented and the applicable CSA standards are met. The records should include the following:
For more information on reporting and record-keeping, refer to GD‑99.1, Guide to the Reporting Requirements for Operating Nuclear Power Plants [5].
To comply with reporting and record-keeping requirements for repairs, licensees should demonstrate that the following criteria have been taken into account:
The following documents contain additional information that may be of interest to persons involved in maintenance programs for nuclear power plants.
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