PLANT LIFE EXTENSION AND AGEING MANAGEMENT

THIAGAN PATHER

MANAGER: NUCLEAR TECHNOLOGY AND WASTE PROJECTS

REGULATORY PHILOSOPHY

• primary responsibility for ensuring protection of the health and safety of the workers and members of the public, as well as protection of the environment, rests with the holder of, or applicant for a nuclear authorisation,

• extends in an unbroken chain through the line management to the workers in the facility.

• As an external “action-forcing” agency, the Regulator influences the actions of the holder/applicant to the extent necessary to ensure protection of the public and worker health and safety.

REGULATORY PHILOSOPHY

• While the Regulator may identify current and potential safety problems and offer alternative strategies for addressing each issue, resolving these safety problems remains the sole responsibility of the holder/applicant.

• It is recognised that regulation can bolster but never replace the commitment of line management and the workers to integrating proper health and safety practices into work planning and performance.

• Regulatory activities are prioritised predominantly on the basis of radiological hazards to the environment, public and the workers; the types and quantities of nuclear and hazardous material; and the process and setting of the operations involved.

REGULATORY PHILOSOPHY

• The NNR ensures that the nuclear authorisation holder meets its primary responsibility with regard to safety, essentially by

– the establishment of safety standards;

– Undertaking review and assessment of applicant/holder safety submissions;

– Performing independent analytical verification;

– the issuance of a nuclear authorisations and regulatory letters; and

– by a compliance assurance programme.

• inspections, surveillance and audits, as well as various forums for interaction with the authorisation holders.

REGULATORY PHILOSOPHY

• The NNR’s approach to the regulation of nuclear safety and security – the potential hazards associated with the facility or activity, – the need for the authorisation holder to establish safety related

programmes commensurate with radiation risks, and – the requirement to exercise regulatory control over technical aspects

such as the design and operation of a nuclear facility.

• The NNR sets safety standards in the form of regulations and

guidance documents.

• The safety standards defines the scope of regulatory control and elaborates the nuclear and security safety principles, requirements, standards, radiation dose and risk limits, criteria and rules.

AGEING MANAGEMENT

• Required that ageing management is considered throughout the life cycle of the nuclear installation

– Design and Preconstruction

– Operation

– Decommissioning

DESIGN AND PRECONSTRUCTION

• Prior to construction approval

– prior safety assessment for a nuclear facility shall include the following design and operation aspects:

• The design of the facility;

• The management of ageing and wear mechanisms, or limiting factors such as cumulative fatigue, embrittlement, corrosion, chemical deposition and radiation induced damage;

DESIGN AND PRECONSTRUCTION

– The design of structures, systems and components important to nuclear safety shall consider the effects of ageing and wear on structures, systems and components both in the provision of design margins and the provision for monitoring, testing, sampling, and inspecting structures, systems and components to assess ageing mechanisms, verify predictions, and identify unanticipated behaviours or degradation that may occur during operation.

– The design should facilitate inspection and testing aimed at detecting ageing mechanisms and their degradation effects.

DESIGN AND PRECONSTRUCTION

• Use of compatible materials and materials with greater ageing resistant properties;

• Considerations should be given to the maintenance requirements and need for material testing programmes.

• This applies also to the modification projects and experimental facilities;

FABRICATION AND CONSTRUCTION

• Service conditions and information on possible ageing mechanisms should be taken into account;

• Records of manufacturing, inspection records, shipment and storage of SSCs should be kept as a baseline data;

• During construction, necessary surveillance specimens for specific monitoring programme should be installed in accordance with the design specifications;

• Commissioning tests should cover identification of hot spots in terms of temperature and dose rates, and measurement of vibration levels, electrical insulation, etc.

OPERATION

• An authorisation holder shall prepare and implement documented programmes for the regular and systematic maintenance, testing, surveillance, and inspection of systems, structures or components which are important to nuclear safety to ensure that their availability, reliability, and required functionality remain in accordance with the assumptions and intent of the design over the service lifetime of the nuclear facility.

• The maintenance and inspection programme shall ensure the reliability and integrity of equipment and plant having an impact on nuclear safety and shall be commensurate with the radiation hazard associated with the nuclear facility.

OPERATION

• Minimization of human errors that may lead to premature degradation, through continuing training, and enhancement of the safety culture;

• Optimal operation of the SSCs to slow down the rate of ageing degradation;

• Proper implementation of maintenance and periodic testing activities in accordance with the OLCs, design requirements and manufacturer’s recommendations;

• Follow-up of possible degradation trends in SSCs between successive periodic testing;

OPERATION

• Use of adequate and qualified methods of nondestructive testing and ageing monitoring for early detection of flaws possibly resulting from intensive use of equipment;

• Appropriate storage of spare parts and consumables susceptible to ageing to minimize degradation while in storage and to control their shelf life properly;

• Feedback of operating experience (both plant specific and generic, including similar RRs, NPP, and industrial plants).

DECOMMISSIONING

• Recognising that some SSC’s will be relied upon during the decommissioning phase of a plant and decommissioning may extend over several years

• it is important that all SSC’s that are relied upon are adequately maintained and can continue to deliver their safety functions for the duration of the decommissioning period.

KEY ELEMENTS IN AN AGEING MANAGEMENT PROGRAMME

• Screening of SSCs for ageing management review: – Based on importance to safety; – Takes into consideration the SSCs replacement ease.

• Minimization of expected ageing degradation:

– Prevention actions should have been defined at the design stage; – Periodic review of the effectiveness of these actions.

• Detection, monitoring and trending of ageing degradation:

– Inspections; – Monitoring; – Performance tests; – Periodic testing.

KEY ELEMENTS IN AN AGEING MANAGEMENT PROGRAMME

• Mitigation of ageing degradation: – Periodic replacement of components; – Refurbishment and modification; – Altering of operating conditions and practices.

• Continuous improvement of the ageing management

programme: – Feedback experience; – Review of programme effectiveness.

• Safety Management System including record keeping.

INTERFACES OF AGEING MANAGEMENT WITH OTHER TECHNICAL AREAS

• Ageing management could be achieved by integration of the following technical areas: – Maintenance, periodic testing and inspection;

– Periodic safety review;

– Equipment qualification;

– Reconstitution of the design basis and maintaining;

– Configuration management;

– Continued safe operation.

MANAGEMENT OF OBSOLESCENCE

CONCLUDING REMARKS

• Ageing management of SSCs should be implemented proactively through out the lifetime of a nuclear installation. – This also applies to refurbishment and modernization

projects.

• In practice, ageing management programme is

accomplished by: – Coordinating existing programmes, including maintenance,

periodic testing and inspection and periodic safety reviews; – Applying good operational and engineering practices; – Incorporating lessons learned from operating experience.

CONCLUDING REMARKS

• Modification projects of major safety significance should be subjected to – review and assessment by safety authorities,

– and to procedures for design, fabrication and construction, commissioning, and safety analysis, as applied to the installation itself.

• Refurbishment and modernization projects should not be limited to a pure replacement of SSCs. – They should also seek for safety improvements to comply

with the up-to-date safety requirements and criteria

THANK YOU Thiagan Pather Manager: Nuclear Technology and Waste Projects National Nuclear Regulator Phone: +27 (12) 674 7192 Facsimile: +27 (86) 589 0294 Mobile: +27 (82) 8825646 Eco Glade Office Park I Eco Glades Office 2 Block GI 420 Witch Hazel Avenue I Centurion P. O. Box 7106 I Centurion I 0046