LIFE EXTENSION AND SAFETY UPGRADING IN INDIAN NUCLEAR POWER PLANTS

摘要

The Indian nuclear power generation programme started with the commissioningrnof twin unit BWRs at Tarapur way back in 1969. Today 14 units, mostly PHWRs, withrntotal installed capacity of 2720 MW are in operation and eight units with installedrncapacity of 3880 MW are under various stages of construction. The new plants are builtrnto current standards and employ the present day technology and hence easily meet thernpresent day safety requirements. The old plants obviously cannot meet these requirementsrnto the same extent since they were built to the standards that existed at the timernof their construction. The Atomic Energy Regulatory Board (AERB) therefore hasrninstituted certain mechanisms and procedures to address the issue of relicensing vintagernplants. Licence renewal, periodic safety review (PSR) and life extension programmesrnare used as regulatory tools for authorizing continued operation of nuclear power plantsrnwith a high level of safety. The regulatory criteria evolve continuously, based onrnoperating experience, identified generic safety issues and new developments in technology.rnThe licensing as well as relicensing procedure in India is designed to respond tornthese evolving safety criteria.rnThe technical assessment of components with respect to ageing, review of thernoriginal design basis along with final safety analysis reports, life assessment of irreplaceablernequipment, structures and components, and plant specific PSAs and their relationshiprnto the traditional deterministic methods are identified as key issues in thernrelicensing or safety upgrading process. The paper deals with the present approach andrnregulatory mechanisms being followed for life extension and safety upgrading in Indianrnnuclear power plants. Also, the safety upgrading and licence renewal of older PHWRsrnand life extension studies carried out in vintage BWRs are described.