Abstract: Prototype Fast Breeder Reactor (PFBR) is a 500MWe pool type, sodium-cooled nuclear reactor, which is presently in an advanced stage of construction. The boundaries of sodium systems of Prototype Fast Breeder Reactor is designed so as to have an extremely low probability of leakage, rapidly propagating failure and rupture under the static & dynamic loads expected during various operating conditions. The degradation of material properties (e.g. effect of sodium, temperature and irradiation), transients, residual stresses, flaw size etc. are the important considerations, which were taken into account. Austenitic stainless steels of grade 316LN were used as major structural materials for the primary and secondary sodium systems of PFBR. Versatile types of systems and varieties of components with complex constructional features require diversities in welding and fabrication processes for the PFBR components. The quantum of welding and fabrication too are fairly large for the large reactor equipment of PFBR. High operating temperature of various systems causing high stresses are minimized by designing thin walled structure. Most of the Nuclear Steam Supply System (NSSS) components are thin walled and require manufacturing in separate nuclear clean halls to achieve high levels of quality. High distortion in stainless steels due to high thermal expansion and low thermal conductivity offers challenge to the fabricators to achieve stringent tolerance in large size PFBR components. The welding standards and acceptance criteria of PFBR equipment are more stringent compared to ASME/other International standards. Various control measures and quality assurance are instituted for reactor equipment during each and every stage of raw material procurement, welding, fabrication, non-destructive examinations, testing, handling, erection and post erection preservation to ensure high degree of reliability against failure for the design service life of 40 years. This paper highlights the challenges involved in welding and fabrication of few of critical nuclear reactor equipment/systems of 500MWe Prototype Fast Breeder Reactor.
Keywords: Quality Management, Welding, Non-destructive examination, Sodium systems.
Title: Quality Management during Manufacture of Block Pile Components for 500MWe Prototype Fast Breeder Reactor
Author: R.G. Rangasamy, Prabhat Kumar
International Journal of Engineering Research and Reviews
ISSN 2348-697X (Online)
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