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Miscellaneous Applications
Published in Vlado Valković, Low Energy Particle Accelerator-Based Technologies and Their Applications, 2022
Several techniques have been used for the measurement of trace amounts of plutonium. Among them, the most commonly used method is alpha-spectrometry. With alpha-spectrometry, the isotope ratio of 239Pu/240Pu cannot be measured because the alpha-particles from both isotopes have nearly identical energies. The 239Pu/240Pu ratio often carries the most important information in a case study, as it reveals the original source (nuclear bombs or reactors of certain types) of plutonium. Among all the analytical methods available today, mass spectrometry seems to be the most promising one to fulfill this need. Both thermal ionization and inductively coupled plasma mass spectrometry (ICP-MS) have reasonable ionization efficiency for plutonium, but they cannot eliminate the hydride and other molecular interferences to yield reliable results. AMS, on the other hand, is capable of counting and identifying an individual atom without any molecular interference. However, the ionization and transmission efficiencies of plutonium in a Tandetron-based AMS system are expected to be low. But the unique feature of AMS, which is necessary for trace-amount plutonium detection, warrants an effect to determine these efficiencies experimentally so that the usefulness of AMS for measuring the plutonium ratio in environmental samples can be established (Litherland 1995).
Radiation Hormesis in Cancer
Published in T. D. Luckey, Radiation Hormesis, 2020
Cancer mortality from plutonium plants with 620 workers who had pulmonary exposure to >150 Bq of plutonium showed hormesis.914 Among the 386 exposed workers at the Rocky Flats Plant, the 67 total deaths and 14 total cancer mortalities were only 70% of expected deaths for the general population. The one lung cancer death was only one fifth of the rate for unexposed workers within the same plant, or one seventh of that expected in the general population. This was statistically significant, p <0.05. This confirmed a similar study of 5413 white male workers at Rocky Flats.992,993 Their follow up was 98.9% complete for all white males who worked at least 2 years between 1952 and 1979. Workers with an average of ≥74 Bq of plutonium in their body had 38% fewer deaths and 29% less cancer mortality than the general population. When compared with workers who received <74 Bq, no significant differences were noted. “The analysis showed no elevated risks for cancer of the tissues that show the highest concentration of plutonium in human autopsy cases and experimental animals, for example, lung, bone, and liver.”57
Physics of Radiation Biology
Published in Kedar N. Prasad, Handbook of RADIOBIOLOGY, 2020
Neptunium has a half-life of 2.33 days, whereas plutonium has a half-life of 24,400 years and is a fissionable element. Natural uranium contains 99.3% 238U and only 0.7% 235U. The natural uranium cannot sustain a chain reaction for two reasons: (1) neutrons from the first fission might escape from the sample, and (2) neutrons might get captured by nonfissionable elements such as 238U. In 1942, many physicists believed that a chain reaction would occur in pure 235U and possibly in an ordinary uranium sample in a properly moderated reactor. The criteria for the moderator were that the elements must be of low atomic material to provide an inelastic collision and at the same time have a very low cross section for neutron capture. Deuterium and carbon are commonly used for this purpose.
Radiological risk assessment of the Hunters Point Naval Shipyard (HPNS)
Published in Critical Reviews in Toxicology, 2022
Dennis J. Paustenbach, Robert D. Gibbons
Pu-239 has a radioactive half-life of 24,110 years and is produced when uranium absorbs a neutron. Small amounts of plutonium occur naturally, but large quantities have been produced in nuclear reactions or released from atmospheric nuclear weapons tests. Pu-239 transitions by alpha decay. Its decay products emit alpha, beta, and gamma radiation depending upon which radionuclide is being evaluated and can pose both an internal and external radiation hazard. Pu-239 is present in most soils in the United States at various concentrations (ICRP 2008; Johnson et al. 2012). The potential for Pu-239 to be present on ships returning from nuclear weapons tests in the Pacific and Pu-239 use in calibrating radiation detection equipment were primary reasons it was identified as an ROC at HPNS (USN 2004).
A review of the impact on the ecosystem after ionizing irradiation: wildlife population
Published in International Journal of Radiation Biology, 2022
Georgetta Cannon, Juliann G. Kiang
Twenty-one years later after the Chernobyl power plant explosion, various isotopes of plutonium, strontium-90, americium-241, and cesium-137 were still detected at high levels causing adverse biological effects across the nearby areas (Voitsekhovych et al. 2007). Wildlife continued to be exposed to substantial radiation doses after humans were evacuated from these areas. The half-life of cesium-137 is approximately 30 years and it decays by β emission to a metastable isomer of barium-137. The half-life of barium-137 isomer is 2 minutes. Subsequently, the metastable isomer emits γ radiation and becomes ground state barium (Baum et al. 2002). Food or water contaminated with cesium-137 that are ingested lead to internal β and γ radiation doses in addition to external radiation doses. The half-life of cesium-134 is about 2 years. Cesium-134 emits β particles. The half-life of strontium-90 is approximately 29 years. Strontium-90 emits pure β radiation. Most of the plutonium isotopes emit α particles, which are ionizing and harmful, but have a short penetration distance. The half-life of plutonium-241 is approximately 14 years. It emits β radiation to become americium-241. The half-life of americium-241 is 432 years, and it emits α particles to become neptunium-237, with a by-product of γ emissions (Baum et al. 2002). This is the composition of radiation released and retained in the soil, water and air across the Chernobyl landscape. In addition to external radiation exposure, ingestion of contaminated food and water by wildlife occurred from the beginning of the disaster and continues to the present.
Mortality among workers at the Los Alamos National Laboratory, 1943–2017
Published in International Journal of Radiation Biology, 2022
John D. Boice, Sarah S. Cohen, Michael T. Mumma, Ashley P. Golden, Sara C. Howard, David J. Girardi, Elizabeth Dupree Ellis, Michael B. Bellamy, Lawrence T. Dauer, Caleigh Samuels, Keith F. Eckerman, Richard W. Leggett
Studies of plutonium workers in Russia have reported increased cancers of the lung, liver and bone for relatively high levels of plutonium intakes, (Koshurnikova et al. 2000; Gilbert et al. 2000, 2013; United Nations Scientific Committee on the Effects of Atomic Radiation 2008; ATSDR 2010; International Agency for Research on Cancer 2012; Sokolnikov et al 2008, 2015; Gillies, Kuznetsova, et al. 2017; Grellier et al. 2017). In some instances, intakes of plutonium were sufficiently large as to cause pulmonary sclerosis of the lung, a deterministic effect (Claycamp et al. 2000). There was little statistical evidence for radiation risks for other organs with lower levels of plutonium deposition (Shilnikova et al. 2003; Hunter et al. 2013; Sokolnikov et al. 2015; Kuznetsova et al. 2016). Studies of plutonium workers in the US and the UK involved much lower levels of plutonium, and radiation-related increases in cancer are not consistent (Wilkinson et al. 1987; Gilbert, Cragle, et al. 1993; Gilbert, Omohundro, et al. 1993; Wiggs et al. 1994; Voelz et al 1997; Omar et al. 1999; Brown et al. 2004; Wing et al. 2004; Wing and Richardson 2005; Agency for Toxic Substances and Disease Registry 2010; Boice et al. 2014).