Memorial Tributes: Volume 26
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  • BAL RAJ SEHGAL (1933-2018)



    Professor BAL RAJ SEHGAL, popularly known as the King of Nuclear Power Safety, passed away at the age of 84 on February 26, 2018, surrounded by his family. Earlier, he was diagnosed with idiopathic pulmonary fibrosis and died due to complications resulting from influenza.

    Bal Raj was born in Peshawar in former British India on September 2, 1933. He and his family migrated to India after the partition in 1947. He obtained his BS in mechanical engineering from the University of Delhi in 1955. After working for a year at the Indian Atomic Energy Commission Bombay, he moved to the United States to pursue his graduate studies at the University of California, Berkeley. He obtained his MS and PhD degrees in 1957 and 1961, respectively. While doing his graduate studies at Berkeley he taught courses on nuclear engineering, neutron transport theory, and reactor experiments. After working as a nuclear engineer for a year at Aerojet General Nucleonics, in 1961 he joined the Reactor Engineering Division of Argonne National Laboratory. He remained there until 1974, when he moved to the newly formed Electric Power Research Institute (EPRI) in Palo Alto, California. He was appointed chair professor of nuclear power safety at the KTH Royal Institute of Technology in Stockholm, Sweden, in 1991. Prior to joining KTH, he held several faculty positions: visiting professor of nuclear engineering at Purdue University from 1973–74, visiting professor in the Department of Nuclear Engineering at the Massachusetts Institute of Technology from 1980–81, and, in the Department of Nuclear Engineering at the University of California, Berkeley, visiting professor from 1982–83 and from 1988–91 and professor in residence from 1991–93.

    Professor Bal Raj Sehgal was an excellent scientist, an outstanding teacher and mentor, and a prolific writer who served the international community with dedication.

    Dr. Sehgal was a world-recognized authority in the area of nuclear reactor thermal hydraulics and safety. This includes both thermal and fast reactors. He was a uniquely gifted researcher who was comfortable carrying out research in many distinct areas of nucleonics and thermal hydraulics. Over his professional and academic career his research work has included experiments, models, analyses, and simulation codes for the prediction of the behavior of nuclear reactor systems under steady-state, transient, and accident conditions.

    At the Argonne National Laboratory he was engaged in the investigation of coupled neutronics and thermal hydraulics in support of the design and operation of light-water and fast reactors. This work saw a significant expansion after he joined EPRI. He was probably the first person in the United States to publish a paper on low-sodium void coefficients in the heterogeneous core design of liquid metal fast breeder reactors (LMFBR). This led to the consideration of such a core for the Clinch River Breeder Reactor. However, the reactor never got built because of a number of issues. He worked on the design of a high-conversion-ratio light-water reactor (LWR) as well. One of the major activities Dr. Sehgal engaged in while at EPRI was the development, enhancement, and validation of system- and component-level computer codes used for modeling LWR system behavior under transient and accident conditions. These included the RETRAN code for modeling the thermal hydraulics of an LWR system under transients, the VIPRE code for the thermal hydraulics of a reactor core, the ATHOS code for steam generators, and the RASP code for core reload design.

    The second major area of his personal research and leadership was the investigation of the source term of severe accidents in LWRs. On behalf of the US nuclear industry, he oversaw the IDCOR Program for degraded cores, which included core heat up, fission product release, and transport and loading of containment. He managed internationally sponsored ACE and MACE programs for source term and coolability during corium-concrete interactions, as well as the development of core meltdown code to determine load on containment and transport and release of fission products.

    As a chair professor of nuclear power safety at KTH, Dr. Bal Raj Sehgal developed one of Europe’s outstanding research programs on reactor safety. This program was supported by Sweden, Finland, Switzerland, the European Union, and the United States. Under this program, a laboratory was set up to conduct large-scale experiments on severe accidents. In addition to severe accident research, the laboratory was engaged in upgrading the safety of Russian RBMK designs (like Chernobyl), boron dilution in pressurized water reactors (PWR), and boiling water reactor (BWR) reliability issues. This laboratory is considered one of the best in the world doing high-impact research in the area of nuclear safety.

    Professor Sehgal served the technical community as North American executive editor of Progress in Nuclear Energy from 1986–93. Subsequently, he remained on the editorial board of the journal. He served for several years as chairman of the governing board for the project on the Severe Accident Research Network of Excellence (SARNET). This board included 54 research and educational organizations from 25 European countries. In addition, he provided leadership on the project on transmutation of nuclear waste (EUROTRANS) and has written and edited chapters for a book on LWR severe accidents.This book brought together knowledge generated worldwide in the area of severe accidents.

    Professor Sehgal received several honors and awards in recognition of his professional contributions. He was elected as a foreign member of the Royal Swedish Academy of Engineering Sciences. He received the Glenn Seaborg Medal, the Tommy Thompson Award for Nuclear Installation Safety, and the Technical Achievement Award of the Thermal Hydraulics Division, all from the American Nuclear Society. He won two best paper awards, one each from the American Nuclear Society and the American Society of Mechanical Engineers. He was a fellow of both societies. Dr. Sehgal was recognized by EPRI with a Technical Excellence Award and by the Japan Atomic Energy Research Institute with a Distinguished Scientist Award. He was elected to the US National Academy of Engineering.

    Professor Sehgal was loved by his students and those who worked with him. He cared for them and helped them in their pursuit of knowledge. His students are now following in his footsteps while developing their own successful careers.

    Bal Raj enjoyed travel, classical music, visiting museums during his travels, and cooking Indian food for his family, friends, and students. He loved his family, was a devoted husband to his wife Aldona, and was a dedicated father to his daughters, Vija (Herb Yee) and Sarita (Patrick Benoit), and his son, Ravinder. He is gone, but his legacy lives on.


    1Sehgal BR, ed. 2012. Nuclear Safety in Light Water Reactors: Severe Accident Phenomenology. 1st ed. Cambridge, MA: Academic Press.