6 Matching Results

Search Results

Advanced search parameters have been applied.

plutonium isotopic analysis in the 30 KeV to 210 KeV range

Description: Low-Energy Gamma-ray Spectroscopy (LEGS) is a nondestructive assay (NDA) technique developed in the 1980s. In 1999, it was modified to include a physical-based model for the energy dependent efficiency. It uses the gamma rays in the energy range from approximately 30 keV to 210 keV, except the 100-keV region. This energy region provides intense, well-separated gamma rays from the principal isotopes of plutonium. For applications involving small quantities (mg to g) of freshly separated plutonium in various chemical forms, it is ideally suited for accurate real-time or near real-time isotopic analysis. Since the last modification, LEGS has been incorporated into the FRAM code (Fixed-energy Response-function Analysis with Multiple efficiency), version 4. FRAM v4 is capable of analyzing the peaks in the whole energy range from 30 keV to 1 MeV, including the X-ray region. The new capability of analyzing the peaks in the 100-keV region greatly enhances the plutonium analysis in the 30 keV to 2 10 keV ranges of the traditional LEGS. We now can analyze both the freshly separated and aged plutonium with greater accuracy.
Date: January 1, 2001
Creator: Vo, Duc T. & Li, T. K. (Tien K.)
Partner: UNT Libraries Government Documents Department

PLUTONIUM ISOTOPIC ANALYSIS WITH FRAM V4 IN THE LOW ENERGY REGION.

Description: Low-Energy Gamma-ray Spectroscopy (LEGS) is a nondestructive assay (NDA) technique developed in the 1980s. In 1999, it was modified to include a physical-based model for the energy dependent efficiency. It uses the gamma rays in the energy range from approximately 30 keV to 210 keV, except the 100-keV region. This energy region provides intense, well-separated gamma rays from the principal isotopes of plutonium. For applications involving small quantities (mg to g) of freshly separated plutonium in various chemical forms, it is ideally suited for accurate real-time or near real-time isotopic analysis. Since the last modification, LEGS has been incorporated into the FRAM code (Fixed-energy Response-function Analysis with Multiple efficiency), version 4. FRAM v4 is capable of analyzing the peaks in the whole energy range from 30 keV to 1 MeV, including the X-ray region. The new capability of analyzing the peaks in the 100-keV region greatly enhances the plutonium analysis in the 30 keV to 210 keV ranges of the traditional LEGS. We now can analyze both the freshly separated and aged plutonium with greater accuracy.
Date: January 1, 2001
Creator: Vo, Duc T. & Li, T. K. (Tien K.)
Partner: UNT Libraries Government Documents Department

Testing the Ortec's Isotopic and Eberlines Snap software for Uranium waste measurements

Description: Uranium enrichment plants normally generate lots of wastes. The wastes are in various matrices such as clothing, glass, concrete, aluminum, and steel, etc. They are in the quantity of a few grams to many kilograms and generally stored in 55-gallon drums. For accountability, it is important to determine the amount of uranium in the waste drums to a certain level of accuracy. There are several commercially available systems that can accurately determine the uranium mass in the waste drums, such as Tomographic-Gamma-Scanner1 (TGS) or Segmented Gamma-Ray Scanner2 (SGS). However, those systems are too cumbersome and expensive. Cheap and simple single detector systems are also available commercially from several companies. The workhorse of these systems is the software, which would work with any germanium detector system. We mocked up waste drums containing several hundred grams to several kilograms of uranium with different isotopic compositions in various matrices. We acquired data using a coaxial germanium detector. We tested two different software codes from two companies, the Ortec's Isotopic software and the Eberline's Snap software. The results with the germanium detector were very encouraging, which led us to test with the NaI detectors. The NaI detectors have much worse resolution than the germanium detectors. However, they are very cheap, can be very large in detector size and, thus, efficient for a given counting time, and are simpler because of not requiring liquid nitrogen for cooling. The results, advantages, and disadvantages of the two software codes and the two detector systems will be discussed.
Date: January 1, 2003
Creator: Vo, Duc T.; Seo, P. N. (Pil-Neyo) & Li, T. K. (Tien K.)
Partner: UNT Libraries Government Documents Department

WASTE CRATE ASSAY SYSTEM (WCAS) : ASSAY SOLUTIONS FOR VERY LARGE REMOTE HANDLED CRATES

Description: An advanced passive neutron counter has been designed and fabricated to measure the plutonium content in large remote handled (RH) waste crates. The waste crate assay system (WCAS) was developed under an agreement between Los Alamos National Laboratory, Japan Nuclear Fuel Limited (JNFL), and BNFL Instruments Inc. (BII) to measure the plutonium content in the waste generated in the Rokkasho reprocessing facility. The primary goal of the design was to produce an assay system for large waste containers. The system also includes 200-L drum pallet assay capability. The measurements are based on neutron-time correlation counting of the passive neutron emissions from the 240Pu, and the plutonium isotopic ratios are used to calculate the total plutonium. The system is designed for both RH waste and low-activity plutonium waste. The system permits the measurement of the singles, doubles, and triples rates and the multiplicity mode analysis is used together with the 'add-a-source' method to correct for the matrix materials in the crates. In the multiplicity analysis, the efficiency for counting the neutrons emitted from the crate is directly calculated from the three measured rates. For improved detectability limits, advanced methods have been incorporated in the WCAS-A to reduce the cosmic-ray neutron backgrounds. These methods include statistical filters and truncation of high-multiplicity events. The paper describes the WCAS-A design, performance, and calibration.
Date: January 1, 2001
Creator: Menlove, Howard O.; Rinard, Phillip M.; Li, T. K. (Tien K.); Romero, M.; Hiruta, K. & Nasuno, S.
Partner: UNT Libraries Government Documents Department

Study of safeguards system on dry reprocessing for fast breeder reactor

Description: A 'Feasibility Study on the Commercialized Fast Breeder Reactor (FBR) Cycle System' is underway at Japan Nuclear Cycle Development Institute (JNC). Concepts to commercialize the FBR fuel cycle are being created together with their necessary research and development (R&D) tasks. 'Dry,' non-aqueous, processes are candidates for FBR fuel reprocessing. Dry reprocessing technology takes advantage of proliferation barriers, due to the lower decontamination factors achievable by the simple pyrochemical processes proposed. The concentration o f highly radioactive impurities and non-fissile materials in products from a dry reprocess is generally significantly larger than the normal aqueous (Purex) process. However, the safeguards of dry reprocesses have not been widely analyzed. In 2000, JNC and Los Alamos National Laboratoiy (LANL) initiated a joint research program to study the safeguards aspects of dry reprocessing. In this study, the safeguardability of the three options: metal electrorefining, oxide electrowinning, and fluoride volatility processes, are assessed. FBR spent fuels are decladded and powdered into mixed oxides (MOX) at the Head-End process either by oxidation-reduction reactions (metal electrorefining and fluoride volatility) or mechanically (oxide electrowinning). At the oxide electrowinning process, the spent MOX he1 powder is transferred to chloride in molten salt and nuclear materials are extracted onto cathode as oxides. For metal electrorefining process, on the other hand, the MOX fuel is converted to chloride in molten salt, and nuclear materials are extracted onto cathode as a metal fomi. At lhe fluoride volatility process, the MOX fuel powder is converted to U&/PuF6 (gaseous form) in a fluidized bed; plutonium and uranium fluorides are separated by volatilization properties and then are converted to oxides. Since the conceptual design of a dry reprocessing plant is incomplete, the operational mode, vessel capacities, residence times, and campaigns are not fully defined. Preliminary estimates of the longest acccptable campaign length while still meets ...
Date: January 1, 2002
Creator: Li, T. K. (Tien K.); Burr, Tom; Menlove, Howard O.; Thomas, K. E. (Kenneth E.); Fukushima, M. & Hori, M.
Partner: UNT Libraries Government Documents Department