Speaker: Dr.R. N. Singh
BARC, Mumbai
Date: 23rd, 2024 (04:00–5.15 p.m. IST)
Venue: Online
Link: https://tinyurl.com/Insis-Seminar-22
Abstract:
Hydrogen generation using renewable energy like solar and wind is one of the clean energy options being considered to mitigate the effect of global warming and climate change. The overall life cycle cost of the technologies for hydrogen generation, storage, transportation and consumption will depend on the endurance of the material of construction used and can be significantly reduced if the operating parameters are so chosen to avoid susceptibility to hydrogen/hydride embrittlement or use materials, which are resistant to hydrogen/hydride embrittlement.
Hydrogen is present in general in all metallurgical processes and under certain conditions causes hydrogen embrittlementresulting in loss of tensile ductility, impact and fracture toughness. Hydrogen is known to cause embrittlement in steels and in hydride forming metals and alloys, which can lead to early failure of the components. Three major forms of hydrogen have been recognized. These are hydride embrittlement(HE), dissolved hydrogen embrittlement(DHE) and hydrogen attack. Hydride embrittlement is caused by formation of brittle hydrides and its fracture.
Two forms of hydride embrittlement have been recognized. These are gross and localized. Gross hydride embrittlement is caused in hydride forming metals and alloys containing hydride volume fraction more than a critical value. For plate shaped hydrides it is significantly influenced by hydride plate orientation with respect to tensile loading direction. In localized form of hydride embrittlementhydrogen migration takes place towards a localized spot where hydride precipitation takes place and results in stable crack growth before final failure of the components.
In this talk various facets of hydrogen/hydride embrittlement of aZr-alloy – a hydride forming alloy, will be discussed at different length scales. A simple method of calculating the stress-free transformation strain of hydride and its use for prediction of shape and orientation of hydride, effect of dissolved hydrogen on tensile and creep properties, delayed hydride cracking, fracture toughness and use of these properties in arriving at the operating pressure of the pressure tube (PT) in pressurized heavy water reactor and leak before break design concept for PT will be discussed.
Bio-data of the speaker:
Dr. R. N. Singh graduated from BIT Sindri in 1988, obtained Ph.D. from IIT Bombay in 2003, joined Metallurgy Division of BARC, Mumbai in 1990 and had carried out extensive work on development of fabrication route for Zr-alloy pressure tubes and various aspects of hydride-induced degradation of mechanical and physical properties of zirconium alloys. He has used both experimental and computational approaches in his studies. He had contributed to the safety assessment and life extension of the pressure tubes of Indian PHWRs.
Dr. Singh was awarded with AvHumboldt fellowship 2004-05, Marie Curie Incoming International fellowship 2005-08 and DAE Scientific & Technical Excellence Award 2007, DAE- Scientific Research Council Award 2010, Metallurgist of the year 2017 and Homi Bhabha Science and Technology Award 2017. He is life member of Indian Institute of Metals, Indian Nuclear Society and Materials Research Society of India.
He has published over 150 articles in peer reviewed Journals / reports / technical papers in conference proceedings.
Presently, he is serving as Head, Mechanical Metallurgy Division, Materials Group of Bhabha Atomic Research Centre, Mumbai.
Organized by:
InSIS and Center for Structural Integrity of Safety Critical Systems, IIT Madras
