PRex: An Experiment to Investigate Detection of Near-field Particulate Deposition from a Simulated Underground Nuclear Weapons Test Vent
AbstractA radioactive particulate release experiment to produce a near-field ground deposition representative of small-scale venting from an underground nuclear test was conducted to gather data in support of treaty capability development activities. For this experiment, a CO2‐driven “air cannon” was used to inject 140La, a radioisotope of lanthanum with 1.7‐d half-life and strong gamma-ray emissions, into the lowest levels of the atmosphere at ambient temperatures. Witness plates and air samplers were laid out in an irregular grid covering the area where the plume was anticipated to deposit based on climatological wind records. This experiment was performed at the Nevada National Security Site, where existing infrastructure, radiological procedures, and support personnel facilitated planning and execution of the work. A vehicle-mounted NaI(Tl) spectrometer and a polyvinyl toluene-based backpack instrument were used to survey the deposited plume. Hand-held instruments, including NaI(Tl) and lanthanum bromide scintillators and high purity germanium spectrometers, were used to take in situ measurements. Additionally, three soil sampling techniques were investigated and compared. The relative sensitivity and utility of sampling and survey methods are discussed in the context of on-site inspection.
Radionuclide Selection for Emergency Response Exercise at Disaster City® Using Unsealed Radioactive Contamination
Abstract The Department of Nuclear Engineering at Texas A&M University currently supports exercises at Disaster City®, a mock community used for emergency response training that features full-scale, collapsible structures designed to simulate various levels of disaster and wreckage. Emergency response exercises can be enhanced by using unsealed radioactive sources to simulate a more realistic response environment following an incident involving the dispersion of radioactive material. Limited exercises are performed worldwide using unsealed radioactive sources, and most of that information is not publicly available. This research compiles the publicly available information along with additional information acquired through discussion with experts and presents the process for selection of a short-lived radionuclide for use at Disaster City®. The historically-used radionuclides were 18F, 99mTc, 82Br, and 140La. These radionuclides were considered for the Disaster City® exercise, as well as other short-lived radionuclides commonly used or capable of being produced at Texas A&M. The selection process described in this paper identified seven radionuclides that could be used in an unsealed contamination exercise at Disaster City®. Radiopharmaceuticals 99mTc and 18F are suitable and available for purchase from nearby vendors. In addition, the Texas A&M Nuclear Science Center TRIGA reactor could be used to produce 24Na, 56Mn, 64Cu, 82Br, and 140La via thermal neutron activation.
Improved culture method for the isolation of Histoplasma capsulatum and Blastomyces dermatitidis form contaminated specimens.
Studies were performed to evaluate a method for selective isolation of Histoplasma capsulatum and Blastomyces dermatitidis from contaminated specimens. Ammonium hydroxide placed on an agar medium surface was found to inhibit the growth of many bacteria, yeasts, and saphrophytic fungi normally found in specimens such as animal tissues and sputum. In one study involving the culture of B. dermatitidis from canine tissues, 24% more isolations were obtained on a medium using NH4OH compared with a similar medium. Increases in the isolation of H. capusulatum from sputum specimens were also obtained, ranging from 20 to 32% compared with four other media without NH4OH.