Graduation date: 1968

Thesis (MTech (Chemistry))--Cape Peninsula University of Technology, 2016. / Radiostrontium (90Sr and 89Sr) has been released to the environment by global fall-out following atmospheric nuclear explosions, by waste discharges and fall-out from the Chernobyl. 89Sr, with a half-life of 50.5 days, quickly decays to undetectable levels, while 90Sr is radiobiologically more important because of its longer half-life of 28.78 years, and because it behaves chemically similar to Ca, and accumulates in bones and teeth. Cost effective and relatively simple procedures for determination of radiostrontium are desirable. An accurate determination of radionuclides from various sources in the environment is essential for assessment of the potential hazards and suitable countermeasures both in case of accidents, authorised releases and routine surveillances. Reliable radiochemical separation and detection techniques are needed for accurate determination of alpha and beta emitters. Rapid analytical methods are needed in case of an accident for early decision-making. At the Koeberg Nuclear Power Station (KNPS), 90Sr analysis are performed on liquid effluent samples making use of the traditional fuming nitric acid method, and subsequent counting of particulate samples on an alpha/beta proportional counter. This method is often at times very time – consuming, and involves many precipitation steps. The use of fuming nitric acid is also very dangerous and could lead to severe personnel injuries in the event of an accident. This project focussed on the application of Sr-Spec resin in the analysis of 90Sr. This work presents the methods for 90Sr analysis for both effluent samples as well as environmental samples. This research also focussed on the calibration of the different radiometric instruments, which are the Liquid Scintillation Counter, the Alpha/Beta Counter as well as the Gamma Detector.

No description available.

Graduation date: 1963

No description available.

The public controversy over possible health hazards from radioactive fallout from atomic bomb testing began in 1954, shortly after a thermonuclear test by the United States spread fallout world wide. In the dissertation, I address two of the fundamental questions of the fallout controversy: Was there a threshold of radiation exposure below which there would be no significant injury? What was the role of a responsible scientist in a public scientific debate? Genetics and medicine were the scientific fields most directly involved in the debate over the biological effects of radiation. Geneticists' prewar experiences with radiation led them to believe that there was no safe level of radiation exposure and that any amount of radiation would cause a proportional amount of genetic injury. In contrast to geneticists, physicians and medical researchers generally believed that there was a threshold for somatic injury from radiation. One theme of the dissertation is an examination of how different scientific conceptual and methodological approaches affected how geneticists and medical researchers evaluated the possible health effects of fallout. Geneticists and physicians differed not only in their evaluations of radiation hazards, but also in their views of how the debate over fallout should be conducted. A central question of the fallout debate was how a responsible scientist should act in a public policy controversy involving scientific issues upon which the scientific community had not yet reached a consensus. Based on their assumption that any increase in radiation exposure was harmful, most geneticists believed that they had a responsibility to speak out publicly about the deleterious effects of radiation. Physicians, who believed in the likelihood of a threshold for significant radiation-induced injury, generally adopted the opposite view. They believed that public discussion of possible, but improbable, radiation hazards was irresponsible because it risked creating irrational public fear of radiation exposure. In my dissertation, I examine how the different positions of geneticists and physicians over what constituted responsible public scientific debate affected the rhetoric of the controversy, as well as the implications of the debate in matters of politics and policy. / Graduation date: 2004

published_or_final_version / abstract / Physics / Doctoral / Doctor of Philosophy

Thesis (Ph. D.)--University of Hong Kong, 2007. / Title proper from title frame. Also available in printed format.

Thesis (Ph. D.) - Oregon State University. / Bibliography: leaves 72-76.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Meteorology and Physical Oceanography, 1982. / Microfiche copy available in Archives and Science / Bibliography: leaves 194-196. / by Joshua Michael Aaron Ryder Wurman. / M.S.