A METHOD FOR ESTIMATING GAS PRESSURE IN 3013 CONTAINERS USING AN ISP DATABASE QUERY

The U.S. Department of Energy's Integrated Surveillance Program (ISP) is responsible for the storage and surveillance of plutonium-bearing material. During storage, plutonium-bearing material has the potential to generate hydrogen gas from the radiolysis of adsorbed water. The generation of hydrogen gas is a safety concern, especially when a container is breached within a glove box during destructive evaluation. To address this issue, the DOE established a standard (DOE, 2004) that sets the criteria for the stabilization and packaging of material for up to 50 years. The DOE has now packaged most of its excess plutonium for long-term storage in compliance with this standard. As part of this process, it is desirable to know within reasonable certainty the total maximum pressure of hydrogen and other gases within the 3013 container if safety issues and compliance with the DOE standards are to be attained. The principal goal of this investigation is to document the method and query used to estimate total (i.e. hydrogen and other gases) gas pressure within a 3013 container based on the material properties and estimated moisture content contained in the ISP database. Initial attempts to estimate hydrogen gas pressure in 3013 containers was based on G-values (hydrogen gas generation per energy input) derived from small scale samples. These maximum G-values were used to calculate worst case pressures based on container material weight, assay, wattage, moisture content, container age, and container volume. This paper documents a revised hydrogen pressure calculation that incorporates new surveillance results and includes a component for gases other than hydrogen. The calculation is produced by executing a query of the ISP database. An example of manual mathematical computations from the pressure equation is compared and evaluated with results from the query. Based on the destructive evaluation of 17 containers, the estimated mean absolute pressure was significantly higher (P<.01) than the mean GEST pressure. There was no significant difference (P>.10) between the mean pressures from DR and the calculation. The mean predicted absolute pressure was consistently higher than GEST by an average difference of 57 kPa (8 psi). The mean difference between the estimated pressure and digital radiography was 11 kPa (2 psi). Based on the initial results of destructive evaluation, the pressure query was found to provide a reasonably conservative estimate of the total pressure in 3013 containers whose material contained minimal moisture content

Measuring Gas Composition and Pressure Within Sealed Containers Using Acoustic Resonance Spectroscopy

Interim and long-term storage of carefully prepared plutonium material within hermetically sealed containers may generate dangerous gas pressures and compositions. The authors have been investigating the application of acoustic resonance spectroscopy to non-intrusively monitor changes in these parameters within sealed containers. In this approach a drum-like gas cavity is formed within the storage container which is excited using a piezoelectric transducer mounted on the outside of the container. The frequency response spectrum contains a series of peaks whose positions and widths are determined by the composition of the gas and the geometry of the cylindrical resonator; the intensities are related to the gas pressure. Comparing observed gas frequencies with theory gives excellent agreement. Small changes in gas composition, better than 1:1000, are readily measurable

Water sorption mechanisms for MIS materials.

The fundamental processes that control the amount of water sorbed by impure plutonium-containing materials after calcination are reviewed. Of particular interest is the amount of and rate of moisture sorption at 1000 PPMv (parts-per-million vapor; -3% RH at 25 'C) and 10,000 PPMv (32% RH at 25 'C). Pure plutonium oxide powders will remain below the 0.5 wt% criterion for packaging in the DOE 3013 Standard at both water vapor concentrations [I]. Deliquescent salts that have been observed in calcined materials by DOES Materials Identification and Surveillance (MIS) program will exceed the 0.5 wt% criterion at 10,000 PPMv and will meet that standard at 1,000 PPMv. Hydrated salts will exceed the 0.5 wt% criterion at all technologically achievable water vapor concentrations if allowed to reach equilibrium. Controlling the moisture availability by controlling the atmospheric content at 1000 PPM' and limiting the access to atmospheric moisture after stabilization through the use of a properly configured stabilization boat will minimize moisture uptake by these materials

Transuranic actinide reactions with simple gas-phase molecules.

The intent of this research is to conduct an experimental study of f-element chemistry fo r the purpose of identifying reaction trends and mechanisms of the early actinide metals with simple gas phase molecules . Previous research has elucidated some of the fundamenta l chemistry of the 4f elements,1-5 however, more complex chemistry is expected for the 5f serie s due to the inclusion of the 5f electrons in the valence shell . The matrix isolation approach, which is well-suited to the experimental study of transient species, will be used for sample collection, and IR/NIR/VIS spectroscopy will be employed to interrogate deposited matrices . The strength of this method lies in the use of isotopes of reactants, which permits the identification of guest molecules in a noble gas matrix by observation of vibrational frequenc y shifts and patterns upon isotopic substitution . Using this technique at the University of Virginia, the first noble gas-actinide bond has recently been identified, a weak U-Ar bond on the CUO molecule.6 Uranium has similarly been observed to bond to krypton and xenon, whereas thoriu m and the lanthanides have not exhibited this activity . It is expected that plutonium will be even more reactive in this respect . We will extend the body of actinide experimental evidence t o include the transuranic elements neptunium, plutonium, and americium reacted with isotopes o f oxygen, nitrogen, hydrogen, carbon monoxide, and carbon dioxide

Analysis of gas constituents from sealed containers of plutonium oxide materials.

The safe storage of pure and impure plutonium oxide materials in sealed containers is a current Department of Energy (DOE) concern. Plutonium oxides sorb moisture from the atmosphere, and the subsequent radiolytic and/or chemical decomposition of the water has been thought to generate excessive hydrogen pressures inside sealed containers. Eleven sealed containers with ten grams each of plutonium oxide materials have been studied for up to four years. The sealed materials were representative materials from the DOE complex and contain less than 0.5 weight percent water. The samples were kept at ambient conditions. We report the final gas analysis of the headspace gas of these containers using gas chromatography, mass spectrometry and Raman spectroscopy. The results show that none of the containers have pressurized significantly, and that hydrogen was not generated in significant quantities

Gas generation over plutonium oxides in the 94-1 shelf-life surveillance program.

The Department of Energy (DOE) is embarking upon a program to store large quantities of plutonium-bearing materials for up to fifty years. The Los Alamos National Laboratory Shelf Life Project was established to bound the behavior of plutonium-bearing material meeting the DOE 3013 Standard. The shelf life study monitors temperature, pressure and gas composition over oxide materials in a limited number of large-scale 3013 inner containers and in many small-scale containers. For the large-scale study, baseline plutonium oxides, oxides exposed to high-humidity atmospheres, and oxides containing chloride salt impurities are planned. The first large-scale container represents a baseline and contains dry plutonium oxide prepared according to the 3013 Standard. This container has been observed for pressure, temperature and gas compositional changes for less than a year. Results indicate that no detectable changes in pressure and gas composition are observed

Gallium Content in PuO{sub 2} Using Laser Induced Breakdown Spectroscopy (LIBS)

Laser Induced Breakdown Spectroscopy (LIBS) has been applied to the semi-quantitative analysis of gallium in plutonium oxide at the Los Alamos Plutonium Facility. The oxide samples were generated by the Thermally Induced Gallium Removal (TIGR) process, a pretreatment step prior to MOX fuel processing. The TIGR process uses PuO{sub 2} containing 1 wt% gallium (nominal) as feed material. Following the TIGR process, gallium content was analyzed by LIBS and also by conventional wet chemical analysis (ICP-MS). Although the data range was insufficient to obtain an adequate calibration, general agreement between the two techniques was good. LIBS was found to have a useful analytical range of 34-400 ppm for Ga in PuO{sub 2}

TECHNICAL BASIS FOR DOE STANDARD 3013 EQUIVALENCY SUPPORTING REDUCED TEMPERATURE STABILIZATION OF OXALATE-DERIVED PLUTONIUM DIOXIDE PRODUCED BY THE HB-LINE FACILITY AT SAVANNAH RIVER SITE

This report documents the technical basis for determining that stabilizing highpurity PuO{sub 2} derived from oxalate precipitation at the SRS HB-Line facility at a minimum of 625 {degree}C for at least four hours in an oxidizing atmosphere is equivalent to stabilizing at a minimum of 950 {degree}C for at least two hours as regards meeting the objectives of stabilization defined by DOE-STD-3013 if the material is handled in a way to prevent excessive absorption of water

TECHNICAL BASIS FOR DOE STANDARD 3013 EQUIVALENCY SUPPORTING REDUCED TEMPERATURE STABILIZATION OF OXALATE-DERIVED PLUTONIUM DIOXIDE PRODUCED BY THE HB-LINE FACILITY AT SAVANNAH RIVER SITE

This report documents the technical basis for determining that stabilizing highpurity PuO{sub 2} derived from oxalate precipitation at the SRS HB-Line facility at a minimum of 625 {degree}C for at least four hours in an oxidizing atmosphere is equivalent to stabilizing at a minimum of 950 {degree}C for at least two hours as regards meeting the objectives of stabilization defined by DOE-STD-3013 if the material is handled in a way to prevent excessive absorption of water