Allan F. Henry/Paul A. Greebler Scholarship

After World War II, Henry, who held a Ph.D. in physics from Yale University, joined Bettis Atomic Power Laboratory as a senior scientist, working on the design of the Nautilus core. He served as manager of the reactor theory and methods group at Bettis from 1954 to 1969. Dr. Henry was a professor at the Massachusetts Institute of Technology from 1969 to 2001.

Paul Greebler received his BS in Physics from the U of Colorado in 1944 and then joined the US Army Signal Corp during WWII. He was discharged in 1946 and worked for Johns-Manville Corp as a senior research physicist from 1946 to 1955, primarily in the area of heat transfer technology. During this period, in 1954, he received his Ph.D. in Physics from Rutgers University. Paul joined General Electric in 1955, and from that point until his death in 1983 Paul worked in the nuclear reactor engineering area with an emphasis on reactor core design, critical experiment design and analysis, and reactor plant safety.

Although Paul was a major contributor to the overall technology of reactor design during the start of the peaceful nuclear power era, a significant technical achievement was his1960 discovery that the Doppler Effect could be a major safety element for the Fast Breeder Reactor. Prior to Paul's work, the Doppler Effect was thought to be too small to affect reactor operation, and fast reactors of the time were designed on the basis of a zero Doppler coefficient, with dependence entirely on core expansion for a negative power coefficient. This led to limitations on the design of fast reactors, and to concerns about their commercial practicality.

Paul's work led to the building of the Southwest Experimental Fast Oxide Reactor, SEFOR, in the late sixties; a project sponsored by the then Atomic Energy Commission, 17 utilities in the southwest, the Karlsruhe Laboratory of West Germany, and Euratom. Paul played a key part in designing the reactor and the experimental program, and in carefully pre-calculating the results of the tests. The final tests had SEFOR go prompt critical, with the Doppler Effect turning the power excursion around. Had one not seen Paul's predictions beforehand, one would have thought his curves were copied from the experimental data.

Today, Breeder Reactor work throughout the world is formulated on the basis of the negative Doppler coefficient. Since it appears that the Breeder reactor may be vital to world welfare in the next century, Paul's contributions in this area should not be forgotten.

Paul was selected for membership in the Sigma Xi and Tau Beta Pi honor societies. He was elected as a Fellow of the American Nuclear Society in 1970 and received the ANS Distinguished Service Award in 1980. He has served the ANS as a member of its Board of Directors (1970-3); Technical Program Chairman (1969); Chairman of Reactor Physics Division (1971-2); Chairman, ANS-19 Standards Subcommittee (1972-7); member Reactor Safety Div. Executive Comm. (1980-3).

Paul was on a number of National Advisory and Planning Committees; he was co-editor of Advances in Nuclear Science and Technology (1965-8); became a Professional Engineer in California in 1976, and was the author of over 100 technical papers on reactor physics, heat transfer and nuclear safety. He has been a major asset to the development of nuclear power.