SSG-80 Commissioning of Research Reactors

IAEA Safety Standards Series No. SSG‑81, Maintenance, Periodic Testing and Inspection of Research Reactors [2];

IAEA Safety Standards Series No. SSG‑82, Core Management and Fuel Handling for Research Reactors [3];

IAEA Safety Standards Series No. SSG‑83, Operational Limits and Conditions and Operating Procedures for Research Reactors [4];

IAEA Safety Standards Series No. SSG‑84, The Operating Organization and the Recruitment, Training and Qualification of Personnel for Research Reactors [5];

IAEA Safety Standards Series No. SSG‑85, Radiation Protection and Radioactive Waste Management in the Design and Operation of Research Reactors [6];

IAEA Safety Standards Series No. SSG‑10 (Rev. 1), Ageing Management for Research Reactors [7];

IAEA Safety Standards Series No. SSG‑37 (Rev. 1), Instrumentation and Control Systems and Software Important to Safety for Research Reactors [8].

Management responsibility: includes providing the means and management support needed to achieve the organization’s objectives (see para. 2.14 of this Safety Guide).

Resource management: includes the measures needed to ensure that resources essential to the implementation of strategy and the achievement of the organization’s objectives are identified and made available (see paras 2.15–2.18 of this Safety Guide).

Process implementation: includes those actions and tasks needed to achieve the goals of the organization (see paras 2.19–2.24 of this Safety Guide).

Measurement, assessment and improvement of the management system: includes activities conducted to evaluate the effectiveness of management processes and work performance (see paras 2.25–2.31 of this Safety Guide).

Regulatory requirements;

Design requirements and assumptions;

The safety analysis report (see Requirement 1 of SSR‑3 [1]);

The operational limits and conditions (OLCs) for the research reactor (see Requirement 71 of SSR‑3 [1]);

Administrative requirements associated with the management of the research reactor.

Planning and prioritizing work;

Addressing regulatory requirements;

Ensuring compliance with the OLCs;

Ensuring the availability of sufficient qualified personnel with suitable skills;

Implementing appropriate procedures and instructions, including those for assessing and correcting non‑conforming items;

Ensuring the availability of special instruments and equipment;

Ensuring a satisfactory working environment, including suitable preparation of the workplace and suitable protection of workers;

Performing and documenting the necessary inspections and tests.

Design documents, and any changes and revisions;

Commissioning procedures, instructions and drawings, and any changes and revisions;

Documents on equipment control and maintenance;

Documentation pertaining to calibration and control of measuring and test equipment;

Commissioning records and results; (f) Other records essential to the performance and verification of commissioning activities.

Having frequent contact with organizations and groups involved in the commissioning, including overseeing of work in progress;

Establishing and implementing a set of performance indicators for commissioning;

Participating in evaluations of the commissioning programme;

Providing feedback derived from commissioning performance indicators for use in the operation of the research reactor.

Review of commissioning procedures;

Verification of commissioning activities by means of inspection, witnessing and surveillance;

Functional testing following maintenance, repair or modification;

Review and verification of commissioning records, results and reports, including those on the status of commissioning, non‑conformance control and corrective actions.

General description of the commissioning programme;

Organization and responsibilities;

Commissioning stages, with tests and prerequisites, and their scheduling;

Commissioning procedures and reports;

Documentation generated by the commissioning programme;

The parts of the management system that address the verification, review, audit and treatment of non‑conformance (see paras 2.26–2.31).

Stage A: Tests prior to fuel loading.

Stage B: Fuel loading tests, initial criticality tests and low power tests.

Stage C: Power ascension tests and power tests up to rated full power.

The sequence of tests for individual SSCs;

The time periods scheduled for the detailed development of procedures, reviews, special training of technical personnel, conduct of testing, development of documentation and reporting of results, as appropriate;

Applicable regulatory requirements, such as the witnessing of tests and inspections by personnel from the regulatory body;

The plan for evaluation of results and, if necessary, for the revision of the safety analysis report.

Organizational structure;

Responsibilities and lines of communication;

Levels of authority;

The approval process;

Interfaces between participating groups.

Activities connected with the final stage of construction and installation of the facility;

Activities fulfilling specific needs of commissioning, including safety reviews;

Activities connected with the operation of the facility.

A management group;

A construction group;

A commissioning group;

An operations group;

Other groups (e.g. the reactor safety committee) as necessary.

Ensuring implementation of the management system with regard to the commissioning programme;

Reviewing and approving the commissioning programme;

Ensuring that commissioning procedures are prepared, reviewed and made subject to approval by personnel with appropriate technical backgrounds and by appropriate committees;

Defining the authorities and responsibilities of groups participating in the commissioning programme;

Establishing lines of communication;

Determining qualification and training needs for personnel;

Periodically reviewing the commissioning programme;

Ensuring the participation of designers in formulating commissioning test objectives and acceptance criteria;

Controlling, reviewing and coordinating activities that involve the participation of more than one group and resolving any problems between the participating groups;

Monitoring the implementation of the commissioning programme;

Ensuring the availability of sufficient properly trained, experienced, qualified and, where required, authorized personnel to perform the commissioning activities;

Ensuring that appropriate action is taken to correct any deficiencies identified during commissioning;

Preparing the comprehensive commissioning report, with input and support from other involved groups.

Ensuring that the installation of SSCs has been completed in accordance with design requirements and specifications and that SSCs are maintained to prevent deterioration before the responsibility for these SSCs is transferred to the commissioning group;

Providing documentation of the as‑built installation and providing test certificates highlighting design changes and deviations that have been approved during the construction stage, for subsequent use as baseline data;

Transferring responsibility for the installed systems to the commissioning group using a documented system;

Assisting the management group in formulating commissioning test objectives and acceptance criteria, in evaluating test results, in correcting deviations and in revising documentation as necessary.

Planning the commissioning programme, including detailed commissioning tests, and preparing schedules and procedures, including sequencing of commissioning activities, prerequisites for tests, review points, and human resources and equipment needs;

Ensuring that personnel engaged in commissioning activities are qualified for the level of responsibility and importance to safety of their work;

Providing training, as necessary, for personnel engaged in commissioning activities;

Interacting with the appropriate groups to establish commissioning test objectives and acceptance criteria;

Establishing a procedure for the systematic recording of data on the facility for future use and a procedure for updating these data;

Establishing a procedure for configuration control to manage modifications (deliberate and unintentional) of the facility;

Establishing and implementing procedures to ensure the orderly transfer of responsibility for SSCs from the construction group to the commissioning group, including the identification of any special precautions necessary for partially installed systems or systems found to be deficient during testing;

Performing necessary maintenance to prevent deterioration of SSCs for which responsibility has been transferred from the construction group to the commissioning group;

Updating the commissioning programme on the basis of experience during commissioning and as a result of design modifications;

Ensuring that the prerequisites for the commissioning tests are satisfied and confirming that the written procedures are adequate and are subjected to a review and approval process;

Ensuring that the commissioning procedures comply with regulatory requirements, including requirements for protection and safety;

Conducting the commissioning tests, including repeat testing of systems that were initially commissioned when partially installed;

Reporting to the operating organization any deficiency detected in commissioning in order that corrective actions can be taken;

Ensuring that when design criteria are not met, design changes are requested, reviewed and implemented;

Certifying that the commissioning programme has been satisfactorily completed;

Issuing reports, certificates and completion assurance documentation and maintaining the necessary records until both the records and the responsibility have been transferred;

Transferring responsibility for commissioned SSCs to the operations group using a documented system;

Confirming that the written operating procedures to be used during routine operation are adequate;

Withdrawing procedures and equipment used in commissioning that are not appropriate to normal operation;

Ensuring that an opportunity is provided for operating personnel to gain experience by utilizing such personnel in commissioning activities as much as possible;

Ensuring proper housekeeping in the facility during commissioning activities.

Participating in commissioning activities and gaining practical training and experience in the operation and maintenance of the facility;

Ensuring that the systems to be transferred to the operations group comply with the requirements for design, performance and safety, and accepting responsibility for the transferred systems;

Operating and maintaining the reactor in accordance with approved operating, maintenance and surveillance procedures during the commissioning;

Updating and validating these procedures and other operational documentation, including the safety analysis report and OLCs.

The safety analysis report (see paras 3.9–3.11 of SSR‑3 [1]);

The OLCs (see para. 7.33 of SSR‑3 [1]), including the specific OLCs for the commissioning of the research reactor;

The management system (see para. 4.12 of SSR‑3 [1]);

The arrangements for handling fuel;

The emergency plan and procedures for on‑site emergency preparedness and response, as well as the arrangements for coordination with off‑site response organizations, as appropriate (see para. 7.90 of SSR‑3 [1]);

Other documents, as required by the regulatory body.

Special precautions necessary for the commissioning of partially installed systems;

Return of systems to the construction group for rectification of defects discovered during commissioning tests;

Retesting of equipment following intervention by the construction group;

Certification by the construction group before systems are first energized;

Handover of the research reactor from construction to commissioning.

Baseline data derived from commissioning;

The existing radiological conditions;

Changes in responsibility for safety, including the nomination of responsible persons;

Conditions for access of personnel;

Control of temporary procedures;

Provision of and procedures for radiation monitoring and radiation protection;

Development of an emergency plan and procedures;

Retention of commissioning records that might have implications for decommissioning.

General correspondence, system records and logbooks;

Acceptance records from the construction stage;

Results of tests;

As‑built diagrams, including electrical, instrumentation, control and flow diagrams;

Records of maintenance and surveillance;

Vendor’s manuals;

Records of initial criticality tests, low power tests and power ascension tests;

Radiation monitoring survey results for full power operation;

An inventory of spare parts and special tools.

Conducting prior testing of systems that are needed for testing other systems;

Ensuring the interdependence of various systems;

Keeping certain systems operational during tests, for safety reasons;

Confirming certain characteristics of the reactor or of systems, for operational or safety reasons;

Grouping together those tests that should be completed before continuing to the next stage.

Commissioning procedures (see Section 6), including related management system requirements;

Commissioning documentation (see Section 7), including design information, preliminary operating manuals, maintenance manuals, OLCs, surveillance and test procedures, and emergency procedures;

Construction documentation (see Section 7), including evidence of pre‑construction environmental qualification testing of structures and equipment, construction test reports, construction deficiency lists and any accepted construction non‑conformances;

The safety analysis report.

B1: Fuel loading tests and initial criticality tests;

B2: Low power tests.

Reactivity measurements, including measurements of the reactivity worth of reactivity control mechanisms³;

Shutdown system tests;

Neutron flux mapping measurements;

Measurements of neutron and gamma radiation fields;

Tests of the primary coolant system;

Confirmation of the response to loss of the electric power supply.

Stage B commissioning tests should be completed, and their results should be evaluated and approved.

The regulatory body should review for approval the results of the stage B tests.

Full reactor systems, including the complete heat removal system, should be demonstrated to be fully functional and ready for full power operation.

C1: Power ascension tests;

C2: Power tests.

Verification that the radiation dose rates in the facility are as expected, and verification of the adequacy of the shielding;

Verification that gaseous, liquid and particulate effluents are at anticipated and acceptable levels;

Verification that reactor parameters and characteristics such as reactivity coefficients and the effects of xenon and other poisons are as anticipated and acceptable.

Determination of contractual acceptance;

Measurement of other effects of experimental equipment that were not previously addressed;

Measurement of fuel management parameters;

Final evaluation of radiation measurements for operational, environmental and experimental purposes;

Determination of the neutron flux and gamma field for beam tubes and irradiation facilities.

The objective of the procedure and, where appropriate, the reason for introducing the procedure (e.g. for validation of an assumption made in the safety analysis);

All the activities that are necessary to confirm the operational acceptability of the item undergoing testing;

Performance parameters that are to be measured under specified steady state and transient conditions;

The performance requirements, together with clearly stated acceptance criteria.

The title and version number of the procedure;

A statement that the most recent approved version of the procedure is to be used;

A summary of the purpose of the tests, the equipment to be tested and the relationship of the tests to the rest of the commissioning programme;

The relationship of the procedure to other procedures;

The expected results of the tests;

Acceptance criteria;

The test methods to be used;

Prerequisites and initial conditions for testing;

Safety measures that need to be implemented during the test;

Precautions to be taken, including, if necessary, stopping the test;

The test conditions and step by step instructions;

A list of equipment needed to perform the tests (including calibrated monitoring instruments);

The type and number of personnel needed, and their duties, responsibilities and qualifications;

Instructions for use of and adherence to procedures;

A list of data to be recorded and checklists to be used;

The methods for analysis of test data and results;

The methods for certification of completed tests;

A list of references.

The purpose of the tests and the expected results;

The safety provisions required to be in force during the tests;

Precautions and prerequisites;

The test procedures;

The test reports, including a summary of the data collected and their analysis, an evaluation of the results, the identification of deficiencies, if any, and any necessary corrective actions.”

The elements of the management system relevant to commissioning.

The commissioning programme.

The comprehensive commissioning report.

Working files and related documents, including the following:

Management records.

Supporting documents, including design reports, as‑built engineering drawings, the safety analysis report, operating procedures, OLCs, maintenance procedures, and vendor specifications and data.

Checklists and logs;

Certificates and approvals;

Reports on significant events;

Reports of deviations and their resolution;

Reports of changes implemented;

Walkdown and handover documentation from construction and commissioning (see para. 4.46).

They demonstrate a capability for safe operation of the research reactor.

They demonstrate the cause of an accident or the malfunction of an item.

They provide baseline data for subsequent use in periodic inspections.

They are necessary for the maintenance, modification or replacement of an item.

They will facilitate decommissioning.

The regulatory body or other relevant organizations require that the records be kept permanently.

Fulfilment of the main safety functions described in Requirement 7 of SSR‑3 [1] (i.e. control of reactivity, removal of heat from the reactor and from the fuel storage, confinement of radioactive material, shielding against radiation and control of planned radioactive releases, as well as limitation of accidental radioactive releases);

Conformance with OLCs.

Implementation of the management system with regard to the commissioning programme.

Completion and documentation of the construction of equipment to be tested during stage A (e.g. records and certificates of installation and calibration, as well as operating and maintenance procedures or manuals for the equipment to be tested).

Performance of preliminary tests and inspections to provide assurance that the equipment is ready for testing (e.g. verification that construction conforms to facility drawings; checks and verifications of records and status of equipment after installation; checks of continuity and separation of wiring, interlocks and protective devices; initial operation and calibration of instruments; adjustment and setting of controllers and limit switches; tagging for handover purposes).

Confirmation that test equipment is operable and calibrated.

Performance of functional tests of individual components or subsystems, for example as follows:

Completion of the writing and review of detailed procedures for stage A tests.

Tanks, valves, pumps and pipes;

Motors and generators;

Fans and ventilation ducts;

Instruments and controls.

Auxiliary systems¹³:

Electrical systems:

Reactor structures:

Instrumentation and control systems¹⁴:

Reactivity control, reactor shutdown and protection systems:

Reactor vessel (or tank) and internals:

Reactor primary and secondary coolant systems¹⁵:

Moderator systems:

Emergency core cooling systems¹⁶:

Reactor building containment¹⁷:

Fuel storage and handling¹⁸:

Radiation protection systems and waste disposal systems¹⁹:

Reactor component handling systems:

Experiments and experimental devices²⁰:

Demonstration of the operability and, where appropriate, the electrical independence of systems;

Verification that communication and alarm devices are loud enough to be heard in the appropriate parts of the facility, but also that alarms are not so loud as to interfere with communications.

Ensuring that all electrical systems are checked and energized;

Adjustment of voltage and frequency, testing of the starting load and full load, and verification of electrical independence;

Checking of the functioning of interlocks, instrumentation and control systems, emergency devices and lighting, indicating and alarm devices, protection devices, relays, circuit logic, transformers, and breakers;

Checking of operation under simulated accident conditions and full loss of off‑site power;

Checking of operation of emergency power initiating devices and the performance of emergency power systems;

Battery discharge tests and verification of the capability of battery chargers, transfer devices and inverters.

Checking of dimensions, alignments, supports, position and fit of flow directing devices, dummy fuel assemblies, reflector elements and other relevant items.

Testing of the operation of functions for normal operation, including regulation, control, monitoring, logging and operation of computer systems (i.e. hardware and software);

Testing of the performance of the protection system, announcements and alarms for anticipated operational occurrences and for remote monitoring and shutdown.

Checking of dimensions, supports, fit and clearances for reactivity control mechanisms;

Demonstration of normal operation and scram, including verification of the response of computer programmes and drive mechanisms, and verification of the performance of sequencing, inhibits, interlocks, alarms, control room indications, rod position instrumentation, run‑in timing and drop times;

Verification of the proper operation of safety system logic and of trip and alarm settings, the response time of measurement channels, and the implementation of satisfactory provisions for redundancy, electrical independence and equipment qualification;

Verification of the proper response to failure modes and loss of electrical power supplies.

Checking for secure installation of removable internals and, where appropriate, retainers such as seal wires, lock nuts or tack welds;

Checking that the beam tube ports are aligned and that plugs are fitted and sealed, and verifying leak tests;

Verification of cleaning, fill and leak tests for the pool and/or tank;

Checking of recirculation, filtration, evaporation rate, purification and make‑up systems, and the level and leakage indication.

Checking of clearances and mechanical supports, and verifying leak tests;

System and component tests, including calibration of flow and pressure measuring instruments, simultaneous operation of auxiliary systems, tests required by applicable codes and standards, and pressure boundary tests;

Verification of correct operation at design flow and pressure, and testing (where possible) for excessive vibration and recording baseline data;

Checking of the provisions for cooling by natural convection.

Checking and testing of the system and components;

Verification of moderator systems flow and functional performance, using dummy reflector elements for loading, withdrawing and locking elements in core locations;

Verification of the operation of the water (heavy water) purification and recombination system.

Testing of the performance of the system in all expected operating modes (under the normal power supply and the emergency power supply) and the proper operation of initiating devices, logic and set points.

Checking of the normal operation of the containment and the heating and/or ventilation systems;

Checking of isolation (i.e. operation, initiation and logic), leak tests (for the full system and components), verification of redundancy and electrical independence as well as compliance with requirements for equipment qualification and with requirements for integrity under accident conditions;

When taking credit for containment, a leak rate test;

When taking credit for exhaust filtration, verification of filter efficiency;

Measurement of exhaust rate and differential pressure across building walls.

Functional tests of all equipment, and leak tests where necessary, and checking of on‑site equipment and training of personnel using a dummy fuel assembly.

Functional tests of all equipment, response tests and calibrations;

Leak tests of liquid waste disposal systems.

Load tests and functional tests of handling equipment and cranes.

Verification of installation and removal of devices, fit tests and, where possible, the proper operation of equipment;

Leak tests.

Access control, in particular for access to the research reactor control room. Guidance on access control for nuclear security purposes is provided in the IAEA Nuclear Security Series [17–19].

Establishment of responsibilities of personnel in emergencies and of criteria for the evacuation of buildings.

Establishment of precautions for fuel handling to prevent damage or inadvertent criticality and to distinguish between differences in fuel types, enrichment levels and poison elements.

Evaluation and approval of the results of the tests referred to in para. A.10.

Preparation of detailed procedures for commissioning substage B1.

The management system, updated as necessary following commissioning stage A.

Completed reviews of the results of the commissioning tests in stage A (see para. A.10).

An updated safety analysis report, as required by the regulatory body. Special attention should be given to non‑conformances, deficiencies and modifications discovered during stage A and their resolution.

Revisions of OLCs on the basis of the results of tests in commissioning stage A, with justification for these revisions.

Reviewed and approved operating procedures for the establishment of initial criticality. These operating procedures should include the following:

Logbooks to sequentially record all relevant operating actions and the location, status and transfers of fresh fuel assemblies.

Checklists and work permits.

Maintenance records, updated to take into account the results of testing and maintenance activities already performed.

Objectives of the substage B1 tests and the expected results.

OLCs for the startup instrumentation and other measuring channels.

Checklists and verification procedures for the startup instrumentation.

The core geometry, including source and detector positions, and the fuel loading plan in accordance with previous analyses.

Fuel loading procedures; administrative criteria and measures regarding results derived from the subcritical multiplication measurements; and estimated reactivity worth for the reactivity control mechanisms in subcritical cores. These criteria may include hold points in the fuel loading process to allow re‑evaluations.

Procedures for measurements of subcritical multiplication and, for subcritical assemblies, the procedure for measuring the subcriticality margin.

Organization and responsibilities of personnel participating in substage B1.

Potential release of radioactive material to the environment during the commissioning process;

Occupational exposure of persons participating in the commissioning programme;

Arrangements for emergency preparedness and response;

Radiation protection equipment relating to the commissioning process, including installed monitoring system, portable monitors and contamination monitors;

Inventory and transfer of radioactive sources;

Training in radiation protection.

Potential non‑radiation‑related risks associated with the commissioning programme;

The management of on‑site emergencies and cooperation with appropriate authorities for potential off‑site emergencies during the commissioning process, if these are considered in the safety analysis;

Training of personnel in emergency procedures;

Provision of drills and exercises.

Tests on protection and reactivity control systems:

Tests on moderator and primary coolant system:

Tests on neutron flux measuring equipment and alarms:

Tests relating to fuel loading:

Subcritical reactivity measurements:

Reactor close to criticality tests:

*Reactor critical tests (not applicable to subcritical assemblies):

Testing of control functions, alarms, rod withdrawal and/or insertion speeds, sequences and indications;

Checking of safety system trip settings, logic, operation and manual scram;

Checks for friction problems in the movement or positioning of reactivity control mechanisms and guides;

*Performance of rod drop time measurements (with and without primary coolant flow) and verification of the operation of shock absorbers.

*Flow tests for vibration during primary coolant flow, tests for differential pressures across the core and major components and for loss of flow and piping leakage;

Water quality tests;

Checks for friction or sticking problems when positioning solid moderator elements.

Final test of alarm and trip settings and actions, using the neutron source.

Satisfactory performance of fuel loading, in accordance with written procedures (i.e. performing a criticality experiment, except in the case of a subcritical assembly);

Independent verification that fuel assemblies and reactivity control mechanisms have been properly placed in their correct positions, in accordance with an approved plan;

Monitoring of the neutron count rates during fuel additions and during the movement of the reactivity control mechanisms for each of the planned individual fuel loads or subcritical cores;

Establishment of criteria for reducing the incremental fuel additions because of the proximity of criticality.

Satisfactory increase of the core reactivity, step by step;

Verification that the neutron flux is continuously monitored, that the reciprocal count rate is plotted against fuel loading, and that results are evaluated to predict criticality or, in the case of subcritical assemblies, the subcriticality margin;

Estimation of the critical mass and reduction of the fuel loading increment as criticality is approached;

Preliminary estimates of the reactivity worth of the reactivity control mechanisms by means of subcritical multiplication measurements.

Assurance that adequate precautions are taken when moving the reactivity control mechanisms (e.g. reducing the amount of reactivity in each movement and waiting longer for the neutron count rate to stabilize);

If necessary, taking of subcritical measurements at regular intervals during the movement of reactivity control mechanisms;

For a subcritical assembly, confirmation of the specified subcriticality margin.

Satisfactory withdrawal of the neutron source, if possible, and readjustment of the position of the reactivity control mechanisms to maintain criticality;

Satisfactory raising of the power to bring the neutron count rate into a responsive range on the instrumentation for subsequent measurements;

Where possible, measurements of reactivity coefficients and the reactivity worth of reactivity control mechanisms (safety, compensating or regulating devices);

Scramming of the reactor and estimation of the reactivity worth of all the reactivity control devices, if possible.

Tests on control and shutdown system:

Flux mapping measurements:

Initial measurements of neutron and gamma radiation levels:

Tests on electrical systems:

Verification of the sensitivity and ranges of neutron instrumentation for indications, alarms, control and protection functions.

Global measurements in the core and the reflector, noting the effects of absorbers and different fuel types and/or enrichment;

Establishment of neutron flux distributions, radial and axial power peaking factors, and critical power ratio;

Local neutron flux mapping near fuel and near absorbers;

Calibration of neutron flux measurement channels and determination of the effect of experimental devices and reactivity control mechanisms on the sensors that cause reactor trips.

Radiation surveys and verification of responses of radiation monitors.

Confirmation of correct responses to loss of electrical power supplies.

Reactivity measurements:

Tests on control and shutdown system:

Flux mapping measurements:

Measurements of neutron and gamma radiation levels:

Tests on primary coolant system:

Tests of electrical systems:

Establishment and verification of excess reactivity and the reactor shutdown margin;

Determination of the reactivity worth of regulating, compensating and safety reactivity control devices and other absorbers;

Determination of reactivity coefficients (e.g. initial isothermal temperature coefficients of coolant, moderator and reflector coefficients, void coefficients);

Determination of the reactivity worth of in‑core and reflector experimental devices, such as loops, rigs, capsules and irradiation sites, that have been installed.

Verification of the sensitivity and ranges of neutron instrumentation for indications, alarms, and control and protection functions;

Verification of operation of reactivity control functions and equipment, such as reactivity insertion and/or removal sequencing, automatic power control, interlocks and computers;

Verification of protection functions, such as trip set points, alarms, timings and shutdown.

Global measurements in the core and the reflector, noting the effects of absorbers and different fuel types and/or enrichment;

Determination of neutron flux distributions, radial and axial power peaking factors, and the critical power ratio;

Local neutron flux mapping near fuel and near absorbers;

Calibration of neutron flux measurement channels and determination of the effect of experimental devices and reactivity control mechanisms on the sensors that cause reactor trips.

Radiation surveys and verification of responses of radiation monitors.

Determination of in‑core coolant flow distribution (if necessary), leakage, vibration, pressure drop and the effect of experimental devices and facilities;

Verification of response to trips and loss of flow tests.

Confirmation of correct responses to loss of electrical power supplies;

If possible, checks to ensure that full loading has no undesirable effects on the performance of instrumentation and control systems.

The stage B commissioning tests should be completed, and the results should be evaluated and approved.

The reviews of the stage B commissioning tests should be completed.

Detailed operating and commissioning procedures for stage C should be prepared.

Reactivity measurements:

Shutdown tests:

Channel calibrations (some of the following calibrations may have been initiated in stage B; however, they should be completed before reaching full power):

Tests on instrumentation and control systems:

Tests on coolant and moderator systems:

Evaluation of steady state core performance:

Measurements of neutron and gamma radiation levels:

Tests on radioactive effluent system and waste monitoring system:

Checks on reactor building:

Tests on other auxiliary systems:

Tests relating to experiments and experimental devices. The following tests, measurements or verifications should be performed either during stage C or during the commissioning of an individual experimental device (some tests may necessitate critical experiments or the use of mock‑ups):

Preparation for routine operation. Before commencing routine operation, the following should be confirmed:

Measurement of temperature, power coefficients and xenon poisoning.

Scram tests to verify trips, including timing following simulated transients.

Calibration of the power measuring channels;

Calibration of safety system measurement channels and readjustment of the safety system settings accordingly;

Evaluation of perturbations, asymmetry and flux tilts.

Checking of the performance of control systems, reactivity insertion and/or removal sequencing and interlocks;

Checking of the operation of other process control systems;

Calibration and verification of instrumentation for flow, pressure, temperature and power;

Checking of control computers and the automatic reactor control system, validation of process variable inputs and performance outputs, and checking of the effects of failures;

Determination of xenon override characteristics during power reduction and shutdown.

Verification of bulk flow rate, channel and/or core flow, pressure drops, leakage and detection, and vibration;

Chemical analysis of the coolant, and checking for radioactive contamination and of alarms for chemical and radiochemical control of the coolant;

Natural circulation tests and checking of the performance of systems for decay heat removal;

Checks of the performance of secondary and tertiary heat removal systems, including chemical and biological analysis where necessary;

Checks of the performance of auxiliary systems (coolant and/or moderator make‑up systems, purification and/or cleanup systems, failed fuel detection systems, auxiliary cooling systems, moderator and/or reflector cooling systems);

Verification of the reactor response to failures of the coolant system, including failures of pumps and valves.

Verification of reactor power measurements;

Verification of fuel and coolant temperatures and core thermohydraulic properties, where practical, by considering surface heat flux, linear heat rate and departure from nucleate boiling ratio, and by assessing the critical heat flux;

Verification that core limits are not exceeded for permitted modes and/ or patterns of reactivity control devices.

Verification of the results of gamma and neutron radiation surveys and of the effectiveness of shielding;

Review of access control;

Verification of responses and calibration of installed and portable radiation monitors.

Verification of calibration of the effluent monitoring system and the waste monitoring system;

Checks of operability of other systems for processing, storage and release of gaseous and liquid waste.

Confirmation of the performance of ventilation systems and air‑conditioning systems (minimum permitted equipment availability at full power), and verification of the performance of the confinement and/or cleanup emergency systems, if not previously demonstrated.

Verification of the performance margins of auxiliary systems necessary for the operation of safety systems and engineered safety features or for maintaining operating environments at minimum equipment design capability;

Confirmation of load carrying capability of equipment at full power;

If applicable, verification of shutdown and monitoring capability remote from the control room;

Confirmation of satisfactory performance following loss of electrical power supplies at full power operation.

Measurement of neutron flux, spectra and gradients for experiments;

Measurement of the reactivity effect of experimental devices (insertion, removal, failure, void);

Tests of effects of experimental devices on flux distributions and on the response of control and safety instrumentation;

Tests of the operation of instrumentation and control systems for experimental devices and auxiliary systems (e.g. emergency power system, cooling system);

Tests of safety devices associated with experimental devices (e.g. alarms, shutdown systems, power setback systems) and any containment features;

Functional tests of equipment for experimental devices (e.g. radioisotope production, heat supply, loop or rig tests, cold source devices, irradiators, beam tubes);

Tests simulating failure of equipment (e.g. loss of loop cooling).

The testing of major reactor experimental devices has been completed, baseline data have been obtained, demonstrations of operability have been performed, and any necessary modifications or adjustments have been made.

Operational documentation, including operating procedures and OLCs, has been revised where necessary.

Commissioning reports have been completed, the safety analysis report has been revised to include the significant results, and an application has been made to the regulatory body for an authorization for operation (including utilization and modification) of the research reactor, in accordance with para. 3.4 of SSR‑3 [1].

Accumulation of baseline data;

Further tests, adjustments, modifications and optimization of parameters to prepare the research reactor for routine operation;

Periodic re‑evaluation of reactivity values (e.g. shutdown margin, worth of reactivity control mechanisms);

Confirmation of predictions of fuel management and of burnup estimates;

Confirmation of adequacy of handling, storage and transport of spent fuel;

Determination of the effect of irradiation on core components and materials (e.g. creep);

Development and confirmation of methods and procedures for experiments and utilization facilities;

Confirmation of adequacy of radiation protection measures, including verification of remote monitoring instrumentation connected to the emergency centre;

Establishment of baseline environmental monitoring data;

Verification of unique operational modes (e.g. remote operation, pulsed modes);

Verification of contractual requirements (e.g. production objectives, long term operation, supply of local heat);

Verification of methods and equipment for utilization (e.g. for the production, handling, processing, storage and transport of radioisotopes);

Long term tests of prototypical features and equipment.

INTERNATIONAL ATOMIC ENERGY AGENCY, Safety of Research Reactors, IAEA Safety Standards Series No. SSR‑3, IAEA, Vienna (2016).

INTERNATIONAL ATOMIC ENERGY AGENCY, Maintenance, Periodic Testing and Inspection of Research Reactors, IAEA Safety Standards Series No. SSG‑81, IAEA, Vienna (2023).

INTERNATIONAL ATOMIC ENERGY AGENCY, Core Management and Fuel Handling for Research Reactors, IAEA Safety Standards Series No. SSG‑82, IAEA, Vienna (2023).

INTERNATIONAL ATOMIC ENERGY AGENCY, Operational Limits and Conditions and Operating Procedures for Research Reactors, IAEA Safety Standards Series No. SSG‑83, IAEA, Vienna (2023).

INTERNATIONAL ATOMIC ENERGY AGENCY, The Operating Organization and the Recruitment, Training and Qualification of Personnel for Research Reactors, IAEA Safety Standards Series No. SSG‑84, IAEA, Vienna (2023).

INTERNATIONAL ATOMIC ENERGY AGENCY, Radiation Protection and Radioactive Waste Management in the Design and Operation of Research Reactors, IAEA Safety Standards Series No. SSG‑85, IAEA, Vienna (2023).

INTERNATIONAL ATOMIC ENERGY AGENCY, Ageing Management for Research Reactors, IAEA Safety Standards Series No. SSG‑10 (Rev. 1), IAEA, Vienna (2023).

INTERNATIONAL ATOMIC ENERGY AGENCY, Instrumentation and Control Systems and Software Important to Safety for Research Reactors, IAEA Safety Standards Series No. SSG‑37 (Rev. 1), IAEA, Vienna (2023).

INTERNATIONAL ATOMIC ENERGY AGENCY, Safety Assessment for Research Reactors and Preparation of the Safety Analysis Report, IAEA Safety Standards Series No. SSG‑20 (Rev. 1), IAEA, Vienna (2022).

INTERNATIONAL ATOMIC ENERGY AGENCY, Safety in the Utilization and Modification of Research Reactors, IAEA Safety Standards Series No. SSG‑24 (Rev. 1), IAEA, Vienna (2022).

INTERNATIONAL ATOMIC ENERGY AGENCY, IAEA Nuclear Safety and Security Glossary: Terminology Used in Nuclear Safety, Nuclear Security, Radiation Protection and Emergency Preparedness and Response, 2022 (Interim) Edition, IAEA, Vienna (2022).

INTERNATIONAL ATOMIC ENERGY AGENCY, Commissioning for Nuclear Power Plants, IAEA Safety Standards Series No. SSG‑28, IAEA, Vienna (2014).

INTERNATIONAL ATOMIC ENERGY AGENCY, Use of a Graded Approach in the Application of the Safety Requirements for Research Reactors, IAEA Safety Standards Series No. SSG‑22 (Rev. 1), IAEA, Vienna (2023).

INTERNATIONAL ATOMIC ENERGY AGENCY, Leadership and Management for Safety, IAEA Safety Standards Series No. GSR Part 2, IAEA, Vienna (2016).

INTERNATIONAL ATOMIC ENERGY AGENCY, The Management System for Nuclear Installations, IAEA Safety Standards Series No. GS‑G‑3.5, IAEA, Vienna (2009).

FOOD AND AGRICULTURE ORGANIZATION OF THE UNITED NATIONS, INTERNATIONAL ATOMIC ENERGY AGENCY, INTERNATIONAL CIVIL AVIATION ORGANIZATION, INTERNATIONAL LABOUR ORGANIZATION, INTERNATIONAL MARITIME ORGANIZATION, INTERPOL, OECD NUCLEAR ENERGY AGENCY, PAN AMERICAN HEALTH ORGANIZATION, PREPARATORY COMMISSION FOR THE COMPREHENSIVE NUCLEAR‑TEST‑BAN TREATY ORGANIZATION, UNITED NATIONS ENVIRONMENT PROGRAMME, UNITED NATIONS OFFICE FOR THE COORDINATION OF HUMANITARIAN AFFAIRS, WORLD HEALTH ORGANIZATION, WORLD METEOROLOGICAL ORGANIZATION, Preparedness and Response for a Nuclear or Radiological Emergency, IAEA Safety Standards Series No. GSR Part 7, IAEA, Vienna (2015).

INTERNATIONAL ATOMIC ENERGY AGENCY, Nuclear Security Recommendations on Physical Protection of Nuclear Material and Nuclear Facilities (INFCIRC/225/ Revision 5), IAEA Nuclear Security Series No. 13, IAEA, Vienna (2011).

INTERNATIONAL ATOMIC ENERGY AGENCY, Physical Protection of Nuclear Material and Nuclear Facilities (Implementation of INFCIRC/225/Revision 5), IAEA Nuclear Security Series No. 27‑G, IAEA, Vienna (2018).

INTERNATIONAL ATOMIC ENERGY AGENCY, Security During the Lifetime of a Nuclear Facility, IAEA Nuclear Security Series No. 35‑G, IAEA, Vienna (2019).

INTERNATIONAL ATOMIC ENERGY AGENCY, INTERNATIONAL LABOUR OFFICE, Occupational Radiation Protection, IAEA Safety Standards Series No. GSG‑7, IAEA, Vienna (2018).