It was John Graham (1933-2017). As Paul says, "for most of my childhood he worked for Westinghouse, modelling nuclear reactors", and he remained in the nuclear industry for the rest of his life. His B.S. in mathematics was from the University of Wales, and he did graduate work at the University of Illinois and the University of London. Here is his short bio from the obituary:
"He was been engaged in nuclear safety for 60 years, including ongoing work with the Pacific Nuclear Council on promotion of peaceful uses of nuclear technologies, since 1997. Graham began a career with Westinghouse in 1969 as Manager of Nuclear Safety at Westinghouse Advanced Reactors Division, Madison, Wisc., with responsibility for safety of the Clinch River Breeder Reactor in Tennessee, among other projects. In 1985, he became the Licensing Manager for the Basalt Waster Isolation Project.
After he left Westinghouse, he was named the Director of Nuclear Safety for Atomic Energy of Canada Limited (AECL) until 1992, when he became vice-president of British Nuclear Fuels (BNFL). He also worked for the U.K. Atomic Energy Agency as a senior scientist and for the Atomic Energy of Canada Research for British Nuclear Fuels as a Director of Safety. He was a recognized Fellow at Westinghouse... He wrote Fast Reactor Safety in 1971 and authored 25 other books."
Nuclear News ran his extended profile when he was the American Nuclear Society president in 1995-96. He was born in Wales, went to college in the US, then returned to England to work in Harwell labs until 1968, when he got a job at Westinghouse ("Claire had good reason to be upset, Graham concedes. They had two small children at that time - Paul, aged four, and Jennifer, who was less than a year old"). They settled at the US and eventually became American citizens. There is a bit on his engagement with mathematics:
"Mathematics was something I've always liked- I love numbers; they're fascinating. I liked algebra. and I love calculus. I truly believe the whole of life is based on calculus and any aberrations in life are simply aberrations in the calculus... I applied to various places and was accepted at the universities
of Ohio and Illinois, and went to the University
of Illinois in 1954-55. I studied quantum
mechanics and mathematics. I didn't stay to
get the master's degree because I didn't think
the master's was at all significant, and besides,
I wanted to take some time to travel around the
States.
I found out
that everybody in that graduate department
was working on similar problems with
slightly different force fields. So I was doing
neutron-deuteron impact problems with a given
force field. Someone next to me was working
with a different force field, and someone
else was doing deuteron-deuteron problems
with my force field. We were all contributing
to the professor's thesis, but we were each only
a very small brick in his edifice. That's not
very satisfying. So I didn't finish that degree..."
However, it does not seem like he did much mathematical work after the early years, aside from nuclear modeling (MathSciNet lists no publications by him). His profile also has a childhood picture of Paul and Jennifer, his kids, and a picture of him, his wife Claire and Paul, age 30, with a short blurb:
"Today, John and Claire live in Golden,
Colo. Claire works in the controller's office
for the American Animal Hospital Association
(you are not allowed to call it Aaha!).
Their son Paul, now age 30, has a doctorate in
computer science, but is currently working as
an artist and as CEO of ARTIX, a World Wide
Web company.
