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INL has shown that a Marinelli beaker geometry can be used for the measurement of radioactive xenon in air using an aluminum Marinelli. A carbon fiber Marinelli was designed and constructed to improve overall performance. This composite Marinelli can withstand sample pressures of 276bar and achieve approximately a 4x performance improvement in the minimum detectable concentrations (MDCs) and concentration uncertainties. The MDCs obtained during a 24h assay for 133Xe, 131mXe, and 135Xe are: 1.4, 13, and 0.35Bq/m3.

Idaho National Laboratory (INL) produces 135Xe, 133mXe, 133Xe, and 131mXe standards for the calibration and testing of the collection equipment and analytical techniques used to monitor radioactive xenon emissions. At INL, xenon is produced and collected as one of several spontaneous fission products from a 252Cf source in a stagnant volume of pressurized helium. Solids are separated from gases by sintered steel filtration. Further chromatographic purification of the fission gases separates the xenon fraction for selective collection. An explanation of gas system, separation, and purification is presented. 135Xe and 133Xe activity ratio adjustments are explained.

Four of the radioactive xenon isotopes ((131m)Xe, (133m)Xe, (133)Xe and (135)Xe) with half-lives ranging from 9 h to 12 days are produced from nuclear fission and can be detected from days to weeks following their production and release. Being inert gases, they are readily transported through the atmosphere. Sources for release of radioactive xenon isotopes include operating nuclear reactors via leaks in fuel rods, medical isotope production facilities, and nuclear weapons' detonations. They are not normally released from fuel reprocessing due to the short half-lives. The Comprehensive Nuclear-Test-Ban Treaty has led to creation of the International Monitoring System. The International Monitoring System, when fully implemented, will consist of one component with 40 stations monitoring radioactive xenon around the globe. Monitoring these radioactive xenon isotopes is important to the Comprehensive Nuclear-Test-Ban Treaty in determining whether a seismically detected event is or is not a nuclear detonation. A variety of radioactive xenon quality control check standards, quantitatively spiked into various gas matrices, could be used to demonstrate that these stations are operating on the same basis in order to bolster defensibility of data across the International Monitoring System. This paper focuses on Idaho National Laboratory's capability to produce three of the xenon isotopes in pure form and the use of the four xenon isotopes in various combinations to produce radioactive xenon spiked air samples that could be subsequently distributed to participating facilities.

Common methods of building linear calibration models are principal component regression (PCR), partial least squares (PLS), and least squares (LS). Recently, the method of cyclic subspace regression (CSR) has been presented and shown to provide PCR, PLS, LS and other related intermediate regressions with one algorithm. When forming a linear model with spectral data for quantitative analysis, prediction results can be adversely affected by responses that do not conform well to the linear model proposed. Wavelength selection can be used to eliminate wavelengths where such problem responses occur. It has recently been reported that CSR regression vectors can be formed by summing weighted eigenvectors where weights are determined from the hat matrix, singular values, and eigenvectors characterizing the sample space. Investigation of these weights shows that wavelength selection based on loading vectors can be misleading. Specifically, by using CSR it is shown that a small weight for an eigenvector can annihilate a large peak in a loading vector. In this study, correlograms are used with CSR regression vectors and eigenvector weights as wavelength-selection criteria. It is demonstrated that even though a model generated by LS for a wavelength subset produces substantially reduced prediction errors relative to PCR and PLS, CSR weight plots show that the LS model overfits and should not be used. Simulated situations containing spectral regions with excess noise or nonlinear responses are examined to study the effectiveness of wavelength selection based on the previously listed criteria. Near infrared spectra of gasoline samples with several known properties are also studied.

The INL has established the capability to process and analyze swipe samples to determine if the amount of U and Pu present on equipment and facilities are at the level typical for natural background, to quantify their isotopic composition and to determine if any off-normal isotopic ratio present in the sample is statistically relevant. A previous report detailed this capability for Pu and preliminarily for U; this report describes the measurements and analysis that were performed to demonstrate the INL capability for U. To establish that a piece of equipment is not contaminated with the element to be sampled, a fabric swipe is used to collect a sample of the materials present on the surface. The swipes are then processed and analyzed to determine if Pu and U are present on the sample at levels above what is accepted as natural background and, for the case of U, whether the isotope ratios deviate from the accepted natural background levels. Both the method applied for chemical processing of the swipes to remove and isolate the U and Pu and the method used to analyze the extracts influences the sensitivity and specificity. Over the years various methods have been developed for processingmore » and analyzing these types of samples; the gold standard for these measurements involves a lengthy and complex separation process followed by analysis using thermal ionization mass spectrometry (TIMS). However, this method is expensive and time consuming, thus driving a need for a less complicated and more efficient method that provides the necessary level of sensitivity and specificity. Advances in Inductively Coupled Plasma Mass Spectrometry (ICPMS) over the last decade have enabled analyses of U and Pu that rival that of TIMS. This, coupled with the potential for simplifying the extraction and separation process required for an ICPMS analysis, prompted the INL’s development of methods that provide the analysis of swipes in a timely and efficient manner. U is present in the blank swipe material at nanogram (~2 x 10-9 g) levels for a typical sample, a level easily detected with ICPMS. The abundance of the isotopes ranges over 4 orders of magnitude for the naturally occurring 234U, 235U and 238U and a goal was set to be able to detect the presence of 236U at 6 orders of magnitude lower than the 238U. The 236U measurement is particularly important because the presence of 236U is a strong indicator that the uranium as been in a nuclear reactor. To demonstrate these capabilities the following sample types were used: blank swipe material, blank process reagents, swipe material spiked with a natural abundance U isotope standard, swipe material spiked with an environmental standard (Columbia River sediment), and swipes taken at various locations within the processing laboratories and the INL environment. This report summarizes the method used to extract the U from the swipe material, the ICPMS analyses that demonstrate the limit of detection (LOD) and the limit of quantification (LOQ) for the U isotopes of interest, the precision of the measured isotope ratios and the dependence of precision on the quantity of U present, and the method proposed to determine if an off-normal ratio is statistically relevant.« less

In October 2012 scientists from both Idaho National Laboratory (INL) and the CTBTO contact laboratory at Seibersdorf, Austria designed a system and capability test to determine if the INL could produce and deliver a short lived radio xenon standard in time for the standard to be measured at the CTBTO contact laboratory at Seibersdorf, Austria. The test included sample standard transportation duration and potential country entrance delays at customs. On October 23, 2012 scientists at the Idaho National Laboratory (INL) prepared and shipped a Seibersdorf contract laboratory supplied cylinder. The canister contained 1.0 scc of gas that consisted of 70% xenon and 30% nitrogen by volume. The t0 was October 24, 2012, 1200 ZULU. The xenon content was 0.70 +/ 0.01 scc at 0 degrees C. The 133mXe content was 4200 +/ 155 dpm per scc of stable xenon on t0 (1 sigma uncertainty). The 133Xe content was 19000 +/ 800 dpm per scc of stable xenon on t0 (1 sigma uncertainty).

The INL made an assessment of the commercially available inductively coupled plasma mass spectrometers (ICPMS) for actinide analysis; emphasizing low detection limits for plutonium. INL scientists subsequently determined if plutonium was present on a swipe, at a 10 million atom decision level. This report describes the evaluation of ICPMS instruments and the operational testing of a new process for the dissolution, separation and analysis via ICPMS of swipes for plutonium and uranium. The swipe dissolution, plutonium and uranium isolation, separation and purification are wet chemistry methods following established procedures. The ICPMS is a commercially available multi-collector magnetic sector mass spectrometer that utilizes five ion counting detectors operating simultaneously. The instrument includes a sample introduction system allowing for sample volumes of < 1 mL to be reproducibly injected into the instrument with minimal waste of the sample solution, while maximizing the useable signal. The performance of the instrument was measured using SRM 996 (244Pu spike) at concentrations of 12 parts per quadrillion (ppq, fg/mL) and with SRM 4350B Columbia River Sediment samples spiked onto swipes at the 10 million atom level. The measured limit of detection (LOD, defined as 3s) for 239Pu is 310,000 atoms based upon the instrument blank data. The limit of quantification (LOQ defined as 10 s) for 239Pu is 105,000 atoms. The measured limit of detection for 239Pu from the SRM 4350B spiked onto a swipe was 2.7 million atoms with the limit of quantification being 9.0 million atoms.

The INL has prepared four standards representing krypton concentrations of 1.1X, 1.54X, 10X and 100X the reported atmospheric value of 70 dpm 85Kr per cubic centimeter of Kr gas at 25 degrees C (ie. 1.1X is 1.1 x 70, or 77 dpm 85Kr per cubic centimeter of Kr gas at 25 degrees C). A t-zero date and time of January 1, 2012 at 1200 Zulu was used for all standards. The Alternative Bench Standards (ABS) of 1.1X, 1.54X, 10X and 100X, are designated by titles of ABS-A, ABS-B, ABS C and ABS-D, respectively. The concentration of Kr in air is 1.14 ppm.

The compositional quality of different lignocellulosic feedstocks influences their performance and potential demand at a biorefinery. Many analytical protocols for determining the composition or performance characteristics of biomass involve a drying step, where the drying temperature can vary depending on the specific protocol. To get reliable data, it is important to determine the correct drying temperature to vaporize the water without negatively impacting the compositional quality of the biomass. A comparison of drying temperatures between 45 degrees C and 100 degrees C was performed using wheat straw and corn stover. Near-infrared (NIR) spectra were taken of the dried samples and compared using principal component analysis (PCA). Carbohydrates were analyzed using quantitative saccharification to determine sugar degradation. Analysis of variance was used to determine if there was a significant difference between drying at different temperatures. PCA showed an obvious separation in samples dried at different temperatures due to sample water content. However, quantitative saccharification data shows, within a 95% confidence interval, that there is no significant difference in sugar content for drying temperatures up to 100 degrees C for wheat straw and corn stover.

Crop residues collected during or after grain harvest are available once per year and must be stored for extended periods. The combination of air, high moisture, and high microbial loads leads to shrinkage during storage and risk of spontaneous ignition. Ensiling is a wet preservation method that could be used to store these residues stably. To economically adapt ensiling to biomass that is harvested after it has senesced, the need for nutrient, moisture, and microbial additions must be determined. We tested the ensiling of senesced wheat straw in sealed columns for 83 d. The straw was inoculated with Lactobacillus plantarum and amended with several levels of water and free sugars. The ability to stabilize the straw polysaccharides was strongly influenced by both moisture and free sugars. Without the addition of sugar, the pH increased from 5.2 to as much as 9.1, depending on moisture level, and losses of 22% of the cellulose and 21% of the hemicellulose were observed. By contrast, when sufficient sugars were added and interstitial water was maintained, a final pH of 4.0 was attainable, with correspondingly low (

Combining biologic pretreatment with storage is an innovative approach for improving feedstock characteristics and cost, but the magnitude of responses of such systems to upsets is unknown. Unsterile wheat straw stems were upgraded for 12 wk with Pleurotus ostreatus at constant temperature to estimate the variation in final compositions with variations in initial moisture and inoculum. Degradation rates and conversions increased with both moisture and inoculum. A regression analysis indicated that system performance was quite stable with respect to inoculum and moisture content after 6 wk of treatment. Scale-up by 150x indicated that system stability and final straw composition are sensitive to inoculum source, history, and inoculation method. Comparative testing of straw-thermoplastic composites produced from upgraded stems is under way.

Straw utilization for composites is limited by poor resin and polymer penetration, and excessive resin consumption owing to the straw cuticle, fines, and lignin-hemicellulose matrix. White-rot fungi degrade these components of straw and could, therefore, potentially be used to improve resin penetration and resin binding without the use of physical or chemical pretreatments. Although long treatment times and large footprints the limit use of fungal treatments on a large scale, distributed fungal pretreatments could alleviate land requirements. In this article, we present progress toward the development of a passive fungal straw upgrading system utilizing white-rot fungi.

Each year, millions of tons of agricultural residues such as wheat straw are produced worldwide. In this paper, we describe ongoing efforts to solve technological, infrastructural, and economic challenges to using this straw for bioenergy and bioproducts. Among these challenges, silica in straw forms a low-melting point eutectic with potassium oxide, causing excessive slagging deposits in boilers. The presence of chlorides causes corrosion beneath the slag deposits on boiler tubes. Silica fouls kilns and fines slow paper machines, limiting the usefulness of straw in linerboard production. Poor resin bonding to the waxy outer cuticle of the straw, poor resin penetration, and high resin consumption due to fines limit the use of straw for straw-thermoplastic composites and for straw particleboard. Poor cellulase penetration limits the use of straw for production of fuels (ethanol) and chemicals. Straw consists of stems, leaves, sheaths, nodes, awns, and chaff. Not all parts of straw are equally valuable. The stems are of higher relative value because they contain much less silica and fines. In contrast, the other plant parts are of relatively lesser value because they are the principle sources of silica and fines. Our approach to reducing silica content is to selectively harvest the straw stems using an in-field physical separation, leaving the remaining components in the field to build soil organic matter and contribute soil nutrients. To address resin issues and cellulase penetration, we are developing distributed windrow system designs employing white rot fungi to upgrade the straw by selectively removing hemicellulose and lignin.

It is important for a modern quantitative analysis laboratory course to contain gravimetric and volumetric analysis exercises implemented with standard unknowns. By analyzing unknowns, students learn crucial laboratory skills. It is also advantageous to introduce real-world samples and cooperative learning structure into the lab course. A one-semester sophomore course at Idaho State University is divided into two parts: students individually perform traditional unknown analyses, and as groups, they study an aquatic ecosystem simulated by a trout aquarium. Ecosystem analyses include the important chemical components of the nitrogen cycle, dissolved oxygen, and alkalinity. In addition to examining the aquatic system, trout are removed temporarily from the aquarium for analysis of lipid and moisture content using near infrared (NIR) spectroscopy. For the ecosystem investigation, students also determine costs of analyses and conduct quality-control studies. At the completion of the course, students are well v...