SSG-74 Maintenance, Testing, Surveillance and Inspection in Nuclear Power Plants

IAEA Safety Standards Series No. SSG‑70, Operational Limits and Conditions and Operating Procedures for Nuclear Power Plants [3];

IAEA Safety Standards Series No. SSG‑71, Modifications to Nuclear Power Plants [4];

IAEA Safety Standards Series No. SSG‑72, The Operating Organization for Nuclear Power Plants [5];

IAEA Safety Standards Series No. SSG‑73, Core Management and Fuel Handling for Nuclear Power Plants [6];

IAEA Safety Standards Series No. SSG‑75, Recruitment, Qualification and Training of Personnel for Nuclear Power Plants [7];

IAEA Safety Standards Series No. SSG‑76, Conduct of Operations at Nuclear Power Plants [8].

Periodic maintenance activities should be performed on a routine basis and should include a combination of external inspections, alignments or calibrations, internal inspections, overhauls, and replacements of components or equipment, as appropriate.

Predictive (condition based) maintenance should involve continuous or periodic monitoring and diagnosis in order to predict equipment failure. Not all equipment conditions and failure modes can be monitored; therefore, predictive maintenance activities should be selectively applied, where appropriate. Such activities include condition monitoring, reliability centred maintenance and similar techniques.

Planned maintenance activities should be performed before unacceptable degradation or equipment failure occurs and should be initiated on the basis of results of predictive or periodic maintenance, vendor recommendations or operating experience.

A systematic evaluation of the purpose and functions of each SSC, to determine the relevant safety requirements and the necessary maintenance activities;

A focus on long term maintenance objectives, and the establishment of a proactive (as opposed to a reactive) maintenance programme;

A reliability centred approach to maintenance;

Planning and scheduling of maintenance on the basis of the objectives of the overall maintenance programme.

The monitored parameters are appropriate indicators of the condition of the SSCs;

Acceptance criteria are clearly defined;

All potential failure modes are addressed;

The behaviour of the potential failure is traceable and predictable.

SSCs that ensure operation of the plant within the established operational limits and conditions, or whose failure could challenge a safety function.

SSCs that are relied on to remain functional following a design basis accident to ensure the continued performance of safety functions, or whose failure could prevent safety related SSCs from performing their functions.

SSCs that are used in emergency operating procedures or are relied on to mitigate the consequences of transients or accidents. Further recommendations are provided in IAEA Safety Standards Series No. SSG‑54, Accident Management Programmes for Nuclear Power Plants [10].

Vibration monitoring;

The shock pulse method;

Oil analysis;

Wear debris analysis and ferrography;

Acoustic leakage monitoring;

Thermography;

Computer modelling for analysis of erosion and corrosion;

Motor analysis techniques;

Motor operated valve testing;

Cable condition monitoring;

Fault detection;

Noise analysis;

Visual inspection;

Performance monitoring;

Specific non‑destructive testing methods (e.g. radiography, ultrasound, ground penetrating radar);

Chemical analysis;

Petrography (for civil engineering structures).

Monitoring plant parameters and system status;

Functional testing;

Checking and calibrating instrumentation;

Testing and inspecting SSCs important to safety;

Evaluating the results of these activities and identifying trends.

The operating organization’s policy and practices for the conduct of operations (see SSG‑76 [8]);

The type of reactor;

The refuelling mode;

The frequency of periodic outages.

The generation of adequate written procedures (see Requirement 26 of SSR‑2/2 (Rev. 1) [1]);

The use of work order³ approvals;

The use of work permits in connection with equipment isolation;

Radiation protection (see Requirement 20 of SSR‑2/2 (Rev. 1) [1]);

Control of the plant configuration (see Requirement 10 of SSR‑2/2 (Rev. 1) [1]);

Calibration of tools and equipment;

Controls for non‑radiation‑related safety (see Requirement 23 of SSR‑2/2 (Rev. 1) [1]);

Controls for internal hazards and external hazards;

Risk assessment (see para. 4.25 of SSR‑2/2 (Rev. 1) [1]);

The use of interlocks and keys;

Qualification and training of personnel (see Requirement 7 of SSR‑2/2 (Rev. 1) [1]);

Control of materials, products and spare parts;

A control plan and programme for lubrication;

Housekeeping and cleanliness (see Requirement 28 of SSR‑2/2 (Rev. 1) [1]);

Management of radioactive waste (see Requirement 21 of SSR‑2/2 (Rev. 1) [1]);

Identification, location and labelling of equipment (see para. 7.12 of SSR‑2/2 (Rev. 1) [1]);

Generation and retention of records (see Requirement 15 of SSR‑2/2 (Rev. 1) [1]);

Planning for work during outages (see Requirement 32 of SSR‑2/2 (Rev. 1) [1]);

Ensuring the safe suspension of work during breaks; (t) Arrangements for shift turnovers.

Allocating responsibilities between personnel performing MTSI activities and personnel directly responsible for plant operation.

Ensuring that operating personnel have adequate information about the plant status at all times during MTSI activities.

Establishing a system controlling the issue and cancellation of documentation such as work order authorizations and work permits for equipment isolation, live testing and access to restricted areas. This includes the designation of persons who are authorized to issue such permits to personnel responsible for performing MTSI activities.

Providing a clear indication of any equipment that is not in service. This includes tagging, where appropriate, and any steps to be taken to prevent unintentional return to service. The tagging should not hide or obscure any displays or indicators on the equipment, nor the labelling of the equipment.

Ensuring that after MTSI activities, SSCs are inspected for their intended operation and, where necessary, are tested by authorized persons before being formally declared functional and returned to service (see para. 8.10 of SSR‑2/2 (Rev. 1) [1]).

The level of detail needed for procedures for MTSI activities;

The types of equipment requiring calibration, surveillance and maintenance;

The criteria and authorities for reporting non‑conformances and for taking corrective actions;

The need for formal logs, records and other documentation;

Equipment to be included in the control of plant configuration;

Controls applied to spare parts;

The need to analyse the history of SSCs in the plant;

The need to perform condition monitoring;

Feedback from operating experience, both internal and external.

Surveillance and inspection should be conducted in accordance with procedures that are sufficiently detailed. Maintenance of items that are faulty or need adjustment, however, will be less predictable. Therefore, the training for maintenance should include special training for specific tasks and/or equipment faults, as appropriate.

It may be necessary to conduct MTSI activities with the plant (or plant systems) out of service or off‑load (i.e. reactor shut down and disconnected from the grid). In such cases, the personnel involved might be under pressure to return the plant or plant systems back into service. The importance of a strong safety culture, in which safety has an overriding priority, should be emphasized in the training programmes, for example by placing the highest importance on reporting and investigating any indication of failure or any unexpected findings and then taking appropriate corrective actions.

MTSI activities, especially maintenance during shutdown, usually consist of a variety of activities with interacting effects, and frequently involve various organizations such as contractors, the regulatory body and the operating organization. The training programme should emphasize the importance of good coordination of organizations, personnel and maintenance activities. Training programmes by and for contractor personnel should be coordinated with training programmes for personnel of the operating organization.

A unique identification: a combination of numbers and letters that identify each procedure and its place in a series. This should be used to identify the procedure in all subsequent programmes, plans and records that refer to it.

Title: a concise description of the subject of the procedure.

Purpose: a brief statement of the purpose and scope of the activity controlled by the procedure.

Prerequisites: all special conditions for the plant, system and/or equipment necessary prior to the commencement of work covered by the procedure. Any necessary special training, simulation or mock‑up practice should also be described.

Limiting conditions: any conditions (e.g. load reduction, the operation of standby equipment or safety systems) that result from performing the work and that limit the plant’s operations. For example, when a system is undergoing repair, surveillance or testing, it should be considered unavailable for safety purposes unless it can be demonstrated that it is capable of performing its safety function to an acceptable degree.

Special precautions: any special safety procedures (e.g. special measures for radiation protection, the securing or removal of loose items) and any necessary control of materials (e.g. incompatible lubricants or chemicals) and environmental conditions.

Special tools and equipment: a list of all special tools, rigging and equipment necessary to perform the work.

References: a list of applicable sections of reference documents that may need to be consulted, such as documents containing baseline data, test and calibration charts, drawings, printouts, instruction books, manuals, applicable codes and standards, photographs and descriptions of mock‑ups.

Step by step instructions: which also are intended to identify any changes in radiological or other conditions as work progresses. At certain points in the procedure, personnel may need to provide a signature (or their initials) to indicate satisfactory completion of the preceding step or steps, either on a copy of the procedure or on an attached checklist.

Inspection witness points: selected points in the work sequence at which an inspection (e.g. for quality control purposes) is to be made. Work should not proceed past this point until the inspection has been performed satisfactorily and documented.

Return to service: the actions and checks necessary for returning the equipment or system to an operational condition after the person responsible has certified that the task has been completed. Where appropriate, independent checking and acceptance criteria should be specified. These criteria should include correct reinstatement and correct compliance with procedures as well as confirmation of system operability (e.g. confirmation of valve line‑up).

Operational testing: any operational testing subsequent to the MTSI activity that is necessary to prove that the equipment is functioning in the intended manner.

Work order authorizations;

Work permits and tagging for equipment isolation;

Radiation work permits;

Non‑radiation‑related safety;

Foreign material exclusion (see paras 5.38–5.44);

Drainage facilities;

Ventilation;

Protection against internal and external hazards;

Electrical and mechanical isolation devices;

Control of plant modifications.

A description of the plant item, the type and scope of work to be performed and the boundaries of the work area in which the activities are authorized;

A confirmation that the plant item either is in a safe condition to work on or meets the prerequisites specified in the procedures applying to the work (such procedures should specify any precautions that need to be taken);

A confirmation of the radiological conditions in the work area, and a description of any precautions necessary for non‑radiation‑related safety and any other precautions to be taken in order that the work be performed safely;

A description of any permissions to be obtained before the work is commenced;

A confirmation that all personnel involved in the work have been withdrawn from the work area after completion of the work and that the plant item either can be returned to service or will remain in a known condition.

Task previews.

Job‑site reviews (i.e. walkdowns to assess physical aspects of the job).

Questioning attitude.

Self‑checking.

The ‘stop when unsure’ policy.

The ‘stop, think, act, review’ methodology.

Procedure use and adherence.

Effective communication, such as the following:

• Three‑way communication;

• Use of the phonetic alphabet.

Pre‑job briefing;

Verification practices, including concurrent verification (i.e. verification performed in parallel by the individuals who perform the task and by those who verify the task), independent verification and peer checking;

Flagging (i.e. highlighting the components that are to be worked on);

Keeping track in step by step procedures (place keeping);

Visualization (using, e.g., charts, specific displays, drawings);

Working through ‘what if’ scenarios during periods of low workload;

Post‑job review.

Thorough planning and scheduling of outage activities (see para. 8.18 of SSR‑2/2 (Rev. 1) [1]);

Assessment of the potential risks associated with planned outage activities (see para. 4.25 of SSR‑2/2 (Rev. 1) [1]);

High quality performance of outage tasks and activities;

Thorough control and monitoring of outage activities;

Review and analysis of outages (see para. 8.24 of SSR‑2/2 (Rev. 1) [1]), and development and implementation of measures to improve future outage performance.

Defining roles and responsibilities.

Addressing the exclusion of both foreign objects and foreign chemicals.

Addressing all components and systems that could be affected by material intrusion, including mechanical components and electric components, whether they are installed, in transport, in storage or in maintenance workshops.

Identifying when and where the nuclear power plant is most vulnerable to foreign material intrusion.

Defining foreign material exclusion areas on the basis of the potential consequences of foreign material intrusion and the difficulties in detecting and retrieving such material. The boundary of each area should be clearly indicated (see para. 5.40), and access controls and specific rules for foreign material exclusion should be applied.

Prescribing good housekeeping and cleanliness practices (see Requirement 28 of SSR‑2/2 (Rev. 1) [1]).

Defining rules for work practices that might increase risk of foreign material intrusion, including the following:

The need to assess the risk of foreign material intrusion for each task.

Rules for the placement of tools and materials, and use of proper logging and accounting practices. A list of tools, materials and instruments needed in each maintenance activity with a risk of foreign material intrusion should be established and this list should be checked before and after the maintenance work.

Rules for securing tools, materials and personal items.

Rules for controlling the use of transparent materials.

Rules for controlling foreign material that is generated as part of work activities.

Rules for protecting open systems and components during work and transportation and for protecting open components during storage, using temporary covers or other temporary blocking systems to limit the spread of foreign material.

Rules and expectations for the reporting of material loss.

Appropriate post‑maintenance testing has been performed (see also para. 8.64);

The configuration of affected systems has been verified;

All relevant records have been reviewed for completeness and accuracy;

Every effort has been made to complete all aspects of the MTSI activity, and any unexpected findings have been reviewed.

The adequacy of the schedule of MTSI activities and its implementation;

The adequacy of MTSI activities in relation to regulatory requirements;

The adequacy of radiation protection controls;

The availability of resources and the effective use of these resources;

The levels of training, experience and competence;

Compliance with the quality management programme;

The adequacy of procedures and instructions;

The effectiveness of reviews undertaken after MTSI activities;

The type and frequency of equipment failures and their impact on plant operations;

The repeated corrective work on the same or similar equipment;

The number and types of deferred and missed maintenance actions;

The adequacy of human resources;

The adequacy and consumption of spare parts;

The adequacy of tools, equipment and facilities;

The accessibility of plant equipment and problems with plant layout;

The type and frequency of human errors and their impact on plant operation.

Adjustments to the frequency of MTSI activities;

Addition or removal of MTSI activities;

Proposals for design changes;

Adjustments to the levels of stocks of spare parts and materials;

Adjustments to human resources and/or training;

Modifications to tools, equipment and facilities, or improvements to plant equipment to facilitate MTSI activities (see also SSG‑71 [4]).

Actions by operating personnel to compensate for the deviation and to maintain the plant within the limits for normal operation. For multichannel systems, this may involve placing the failed component or channel in a fail‑safe state until repairs and testing have been completed.

Notification of managers at the appropriate level of the operating organization.

Corrective maintenance or a modification, to be performed by operating personnel in collaboration with specialist contractors, as necessary.

Assessment of any safety implications of the deviation with regard to future operation, corrective maintenance and the surveillance programme.

Consultation, if necessary, with design personnel and other specialists.

Assessment of the implications of the deviation with regard to the following, as appropriate:

Modifications to the appropriate documents, procedures, plans and drawings.

The design of the system or component;

The computer modelling of the system;

The training of operating personnel;

Operating procedures;

Emergency arrangements;

Regulatory requirements.

Collecting, evaluating, classifying and recording details of abnormal events or findings to detect precursors, common mode failure mechanisms and deficiencies in equipment, procedures, personnel or the operating organization;

Sharing experience gained from MTSI activities with designers to improve the design of future plant features that have a bearing on such activities, such as ease of access, ease of disassembly and reassembly, and implementation of arrangements for the protection and safety of operating personnel;

Utilizing experience from MTSI activities in the training of personnel;

Validating accumulated reliability data to be used for probabilistic evaluations and for the technical specification of new components;

Ensuring the retrievability of data and the proper transfer of relevant information to appropriate organizations (see paras 5.27 and 5.32 of SSR‑2/2 (Rev. 1) [1]).

The scope and frequency of MTSI activities should be adequately identified to maintain the status of qualified equipment throughout the lifetime of the plant under normal operation, anticipated operational occurrences and accident conditions.

Equipment within the qualification programme should be adequately identified when the work request for MTSI activities is issued.

After maintenance activities, qualified equipment should be reinstalled in accordance with applicable installation procedures.

The status of qualified equipment should be preserved after maintenance activities (e.g. mounting bolts should be torqued to the proper values, and parts with limited life expectancy should be replaced as necessary).

Maintenance activities should involve the replacement of components as necessary to preserve the qualified configuration.

Spare parts and components used for qualified equipment should be identical or equivalent to the original parts and components.

Preparations should be made to investigate unforeseen mechanisms that might be causing equipment degradation, deviations and anomalies in a timely manner after they have been detected.

Deviations and anomalies should be properly evaluated in a timely manner after they have been detected.

Periodic inspections and maintenance activities for mechanisms that are not amenable to simulation during equipment qualification should be identified.

Identification of SSCs important to safety that are susceptible to ageing mechanisms;

Identification of ageing effects that could adversely affect the fulfilment of safety functions by SSCs;

Adequate and up to date methods for detecting and monitoring ageing effects;

The keeping of appropriate records to enable trends in ageing effects to be analysed;

Corrective actions to prevent and/or mitigate the effects of ageing mechanisms;

Any necessary changes to the programmes of MTSI activities indicated by the results of the ageing management programme.

Tests of all safety functions;

Tests to detect failures that cannot be revealed by self‑checking of the system or by alarms or anomaly indicators;

Tests of the main non‑safety‑related functions to detect any degradation of their performance.

The importance to safety of the structures, systems and components, with insights from probabilistic safety assessment taken into account;

Their reliability in, and availability for, operation;

Their assessed potential for degradation in operation and their ageing characteristics;

Operating experience;

Recommendations of vendors.”

The recommendations of designers and vendors;

The results of condition monitoring;

The opportunities for on‑line maintenance based on deterministic and risk analysis considerations;

The need to keep radiation doses as low as reasonably achievable.

An office area (if not provided elsewhere), including facilities for the processing and storage of records and procedures;

A fitting and overhaul area with suitable workbenches for the disassembly, repair and reassembly of those plant items that are intended to be dealt with in the workshop;

Secure storage facilities for special tools and testing equipment needed for maintenance activities;

Material handling facilities;

Sufficient illumination.

Mechanical workshops:

Electrical workshops:

Control and instrumentation workshops:

Other items:

Space and equipment for welding, sheet metal and plate fabrication, pipe fitting, and handling of heavy equipment and materials;

Machine tools such as lathes, milling machines, shapers, pedestal drills, grinders and presses;

A room with equipment for lapping, polishing and surface checking.

Test benches with appropriate power supplies connected;

A motor overhaul and test facility;

A high voltage test area with controlled access;

Instrument and relay testing and calibration facilities;

A small coil rewind facility.

Test benches with the necessary electrical, electronic, pneumatic and hydraulic supplies and test equipment;

Calibration and testing facilities for instruments, controls and portable calibration equipment;

A facility for safe fault finding on energized equipment.

Facilities for acceptance testing of overhauled and/or replacement equipment, as necessary;

Preventive maintenance tools such as vibration analysers, bearing monitoring tools and non‑destructive testing facilities.

Access control and changing rooms;

Personal protective equipment;

Ventilation with discharge filters;

The handling and temporary storage of solid and liquid radioactive waste;

Equipment for radiation monitoring and radiation protection;

Equipment for shielding and remote handling;

The storage of radioactive items in compliance with regulatory requirements;

The segregation of non‑conforming items from conforming items⁴;

Decontamination facilities (see paras 8.14–8.16);

Access structures and platforms, if necessary.

Access control and changing rooms;

Ventilation with discharge filters;

Handling and temporary storage of solid and liquid radioactive waste;

Treatment, conditioning (as applicable) and dispatch of solid and liquid radioactive waste for subsequent processing for disposal;

Equipment for radiation monitoring and radiation protection;

Decontamination tanks and special equipment capable of accommodating the largest items that might need decontaminating;

An adequate electric power supply and adequate supplies of steam, hot water, compressed air and appropriate chemical decontaminating agents;

Other decontamination systems, such as those that use glass blasting or ultrasonic techniques.

Rehearsing work to be performed in areas with high radiation levels or on highly contaminated plant items, particularly for personnel not familiar with the plant or for an unusual or specialized task;

Preparing and validating maintenance procedures to avoid errors and reduce occupational exposure;

Gaining experience in the use of tools and protective equipment;

Developing and improving tools and equipment;

Training personnel for specific work, and confirming estimates for work durations to manage occupational exposure.

Remote handling manipulators and remotely operated special purpose tools;

Automatic welding and cutting equipment;

Remotely operated non‑destructive testing equipment;

Automatic in situ valve seat lapping machines;

Remote viewing equipment such as shielded windows, mirrors, binoculars, telescopes, periscopes, boroscopes, fibrescopes and closed circuit television with remotely operated cameras;

Communication systems such as telephones and radios, and communications equipment for use when protective respiratory equipment is being worn;

Special containers for contaminated items;

Shielded containers and portable shielding;

Personal protective equipment;

Active dosimeters for increasing awareness of occupational exposure and improving its management;

Materials and equipment for controlling and containing radioactive contamination (e.g. plastic sheeting and tents, paper floor covering, suction cleaners, floor cleaning equipment);

Fixed or rapidly assembled equipment for access in order to reduce occupational exposure (e.g. permanent ladders or telescopic cradles).

The number and importance of plant items that could be subject to failure;

Any special features of a manufacturing process that would preclude the subsequent manufacture of a plant item;

Any uncertainties in the future supply of spare parts and components that are currently available, especially with regard to the risk of technological obsolescence;

Anticipated delivery times;

The estimated duration of repairs to a plant item in comparison with the time that the item is permitted to be unavailable by the operational limits and conditions;

The shelf life of spare parts, components and consumables.

It should be confirmed that the original design, fabrication and inspection requirements will not be compromised.

Mechanical interfaces, fits and tolerances affecting performance should not be adversely affected by the application of revised or new industrial codes or standards.

The materials used should be compatible with and suitable for the installation and the operating requirements of the system.

The objectives of the maintenance have been achieved.

The SSC is capable of performing its functions.

The operational limits and conditions of any related system are being complied with.

Safe operation of the plant has been verified.

The integrity of the barriers between radioactive material and the environment (e.g. fuel cladding, the primary pressure boundary, the containment);

The availability of safety systems such as the protection system, the safety system actuation systems and the safety system support features (see SSG‑39 [19]);

The availability of items whose failure could adversely affect safety;

Evaluation of the structural properties (e.g. strength, humidity) and ageing assessment of safety related concrete containment structures, using test specimens created during the construction stage and stored in corresponding environmental conditions.

To describe in sufficient detail the aims of the surveillance programme in terms of ensuring compliance with operating limits and conditions and with other criteria that are applicable to SSCs important to safety;

To specify the frequency of surveillance activities and provide for the scheduling of surveillance activities;

To specify the surveillance requirements (see para. 4.10(d) of SSR‑2/2 (Rev. 1) [1]) for each operational limit and condition and provide appropriate procedures to be followed in the conduct and assessment of each surveillance activity; (d) To verify that SSCs important to safety remain within the operational limits and conditions;

To specify the authorities and responsibilities assigned to individuals and groups and to off‑site organizations involved in surveillance activities;

To specify the necessary qualifications and training of personnel performing surveillance activities;

To indicate the points at which tests are necessary and deficiencies, if any, are to be rectified;

To specify the arrangements for record keeping and for the retention and retrievability of such records;

To provide cross‑references to other documents relevant to the surveillance programme;

To ensure that periodic reviews of the surveillance programme are performed (see paras 5.57–5.63).

The safety analysis report, the operational limits and conditions, and regulatory requirements;

The results of the commissioning programme, with particular attention paid to baseline data, the as‑built state of the plant and the acceptance criteria;

The availability of items important to safety, and the detection of deficiencies and incipient failures that might occur during operation or prior to returning items to service after maintenance, repair or modification.

Supporting procedures are developed, reviewed and approved in a timely manner.

Surveillance procedures are tested, to the extent practicable, during commissioning.

Certain parameters are recorded during and after construction (but prior to the commencement of operation) for use as reference points in surveillance monitoring. Certain benchmarks and alignment points should be permanently marked, measured and recorded to provide as‑built reference points for subsequent comparison.

Inspection of new fuel, core components and associated items such as flow restricting devices and locating devices, in accordance with an agreed schedule before loading into the core. This inspection should include visual and metrological methods as well as more sophisticated methods such as helium tests.

Monitoring of thermal and hydraulic conditions such as flow, temperature, pressure and gross and local power, in order to ensure compliance with operational limits and conditions.

Monitoring of the activity and chemical composition of the reactor coolant (e.g. by sample analysis).

Inspection of irradiated fuel before reuse, storage or transport (e.g. by visual inspection or leakage tests).

Monitoring of the activity and chemical composition of water or gas in the irradiated fuel storage facilities.

Monitoring of radioactive discharges to the environment.

Leak rate measurements, for example by measuring the flow of make‑up water to the primary coolant system or the flow to the leakage collection sump (a steady state condition is generally necessary for such measurements in order to eliminate transient effects);

Inspection of and hydrostatic pressure tests on the primary pressure boundary;

Recording of system transients and their comparison with the assumptions made in the safety analysis report, where appropriate;

Testing of the operability and tightness of closure devices that are part of the pressure boundaries;

Monitoring of leakage detection systems (e.g. instruments for process and area monitoring, temperature detectors, acoustic detection equipment);

Monitoring to ensure that transition temperature criteria (e.g. reference nil‑ductility) are satisfied;

Monitoring of the chemical composition of the primary and secondary reactor coolants, as appropriate;

Monitoring of samples of reactor pressure vessel components that are subject to irradiation.

Leakage tests performed on the containment;

Tests of penetration seals and closure devices such as air locks and valves that are part of the boundaries, to demonstrate their leaktightness and, where appropriate, their operability;

Inspections for structural integrity (such as those performed on liner and prestressing tendons);

Monitoring of conditions within the containment such as temperature, pressure and atmospheric composition;

Monitoring of the mechanical behaviour of the containment in operation and during tests by means of an instrumentation system (measuring overall deformation and displacement).

Residual heat removal systems;

Safety injection systems;

Containment spray systems;

Chemical and volume control systems;

Treatment systems for radioactive liquid waste;

Core spray systems (for boiling water reactors).

A system leakage and hydrostatic pressure test as part of the pre‑service inspection;

A system leakage test before resuming operation after a reactor outage in which the leaktightness of the reactor coolant pressure boundary might have been affected.

Protection of the primary systems against unacceptable pressure surges (e.g. by steam dumping or by actuation of safety valves and relief valves);

Actuation of protection systems as intended.

Emergency core cooling and heat transport to the ultimate heat sink;

Isolation of the containment;

Cooling of the containment and limiting of the pressure;

Control of radioactive discharges arising as a result of accidents;

Control of combustible gases within the containment;

The correct functioning of the standby shutdown system.

Emergency power;

Cooling water;

Air;

Component cooling and lubrication;

Control and instrumentation.

Systems that are relied on for shutting down and cooling the reactor under normal operation, including control systems such as those provided to control and monitor reactivity, primary water chemistry, feedwater supply, reactor pressure and temperature;

Instrumentation for operational states and for accident conditions;

The control room (i.e. with regard to habitability and access);

High energy piping and associated piping restraints;

Structural supports (e.g. stack stay wires, pipe supports);

Systems for the prevention, detection and suppression of fire and other hazards;

Emergency response facilities and equipment;

Protection systems for internal events and for external events;

Communication systems;

Storage facilities for irradiated fuel, including cleanup systems;

Fuel handling equipment and facilities;

Facilities for the treatment and storage of radioactive waste;

Speed control systems for turbines and for generators and their protection systems, where appropriate;

Monitoring systems for radiation and for contamination;

Measures for physical protection.

To ensure that plant parameters, including the availability of SSCs important to safety, continue to remain in compliance with operational limits and conditions;

To detect incipient failures or the need for more frequent maintenance, in order to ensure the satisfactory functioning and availability of SSCs important to safety;

To ensure that a defect does not develop and/or grow between two successive surveillance activities to such an extent as to become unacceptable or to lead to accident conditions;

To provide information that allows an assessment of the possible effects of excessive fatigue and/or premature ageing;

To meet regulatory requirements and to comply with applicable industrial codes and standards.

The need to meet reliability objectives;

The expected mechanisms of failure and the results of reliability analyses;

The type of component, the conditions of service and the age of the item or system;

Internal or external operating experience of failure rates gained from maintenance or from experience in the plant or in similar plants;

The extent of automation of the surveillance.

The extent of redundancy of the respective system in relation to the need to remove SSCs from service for surveillance;

Operational restrictions that have a bearing on the implementation of surveillance activities;

The scheduling of surveillance activities in conjunction with other activities such as planned maintenance and shutdowns or other operating cycles;

Facilitating the performance of a number of surveillance activities during a shutdown;

Flexibility to allow reasonable safety margins without impairing the effectiveness of surveillance;

Flexibility to allow surveillance activities to be performed during unplanned shutdowns;

Flexibility to allow the performance of tests at a time when plant conditions are most suitable with regard to both the validity of the surveillance and the safety of the plant;

The need to conduct surveillance without placing an undue burden on the operation of the plant and while still ensuring safety;

The need to perform surveillance in conditions that are as close as possible to the normal operating conditions of the systems and components involved;

The need to avoid spurious reactor trips or adverse effects on operation;

The need to avoid any unnecessary shortening of the service life of a component or the introduction of errors by an excessive series of tests and operations;

The need to keep occupational exposure as low as reasonably achievable.

The difficulty in obtaining statistically meaningful data on fault events of low frequency.

The difficulty in conducting sufficient testing to provide conclusive reliability figures. In such cases, the frequency of surveillance activities should be derived on the basis of the best estimates of future failure rates.

The difficulty in assessing the significance of common cause failures.

The performance of the SSCs, particularly their failure rate;

The corrective actions necessary after a failure;

The performance of similar SSCs in similar plants and environments;

Design changes associated with SSCs important to safety;

Information on failure modes that cause abnormal occurrences or accidents;

The effects of component ageing.

Comparing readings on instrument channels that monitor the same variable, with an allowance for differences in the process variable between sensor locations;

Comparing readings between instrument channels that monitor different variables with a known relationship to each other.

There is adequate evidence that ageing will not degrade the performance of the instrument beyond acceptable limits.

The manufacturer’s test results are not invalidated by the design of the system in which the sensor is installed.

The tests have been performed and the test results documented in accordance with the quality management requirements of the operating organization’s management system.

Manual startup of equipment. The test duration should be sufficient to achieve stable operating conditions. Where starting a specified component is not practicable, operation of the starting device in the ‘test’ position may be acceptable if the component is subsequently tested at the first opportunity provided by plant operations.

Manually controlled electric operation of valves, with timing of the stroke, if appropriate. In cases where a full stroke of the valve is not appropriate because of the operating conditions, a partial stroke test or a test of the valve control system may be acceptable; however, full stroke testing should be done routinely during plant shutdown, in conditions representative of operation where this is possible.

Activation of a test signal of an appropriate magnitude to give a suitable actuation of the output or a readout, as necessary.

Initiation of the actuating device and observation of the result.

Testing of automatically calculated set points to verify the responses to each input variable.

Checking of the manual initiation of the performance of safety functions.

Testing of the status and operability of interlocks, bypasses, bypass and test indications, and bypass and test annunciation circuits.

Monitoring of the appropriate parameters during the test.

Equipment identification: test equipment used as a calibration reference standard should be identified, to enable verification of its calibration status.

Equipment verification: before test equipment is used in a surveillance test, its calibration status and operability should be verified.

Calibration procedures: detailed procedures should be provided for the calibration of test equipment. The accuracy of calibration should be commensurate with the functional requirements and, where appropriate, reference standards should be used.

Calibration records: records should be maintained for each piece of equipment to be able to demonstrate that established schedules and procedures for calibrating test equipment and reference standards have been followed.

Logs and logbooks in which the readouts of safety system parameters are noted;

Data recorder charts and computer printouts;

Reports of tests, calibrations and inspections, including evaluation of results and corrective actions taken;

Surveillance procedures;

Records of completed surveillance activities;

Reports of relevant reviews and audits;

Checklists for the status of systems and components.

Pressure retaining parts of the reactor coolant system;

Components of the primary reactor coolant system (and components connected to this system) that are essential for ensuring shutdown of the reactor and cooling of the nuclear fuel in operational states and in accident conditions;

Other components, such as main steam lines or feedwater lines, whose dislodgement or failure might adversely affect the SSCs described in (a) and (b).

The objectives of the qualification programme;

The qualification level⁶, if this has been specified;

The method for assessing the technical justification;

The methods by which the non‑destructive testing system will be assessed;

Details of how the qualification testing will be conducted (e.g. blind, open⁷);

Details of the qualification test pieces (in the case of blind trials, some aspects may be confidential);

The method for evaluating the results of the qualification.

Specifications for SSCs and as‑built drawings. This should include component drawings, material specifications, heat treatment records, records of the manufacturing process, specifications and drawings for fabrication and installation, and records of any acceptance of deviations from the specifications.

Samples of materials used.

Records of personnel qualification.

Pre‑service inspection data and reports.

The inspection programme and detailed inspection and test procedures (including relevant codes and standards).

Calibration records.

Acceptance criteria.

Information on the identification of components, the location and size of the inspection area, work technique, type of equipment, type of sensor, calibration equipment and sensitivity standards, such that the inspection activity could be repeated and similar results obtained;

All relevant indications that exceeded the minimum recording level, and all pertinent information concerning these indications (e.g. location, magnitude, length);

Test reports, recordings and charts (if no such records are generated, this should be noted in the records);

Comparisons with previous results and evaluations;

Reports of the evaluations of the results of inspection activities;

Information on the radiation doses received, as appropriate.

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