Gas Concentration Measurements in Underground Waste Storage Tanks

Currently over 100 underground tanks at the Hanford facility in eastern Washington state are being used to store high-level radioactive waste. With plans for a long-term nuclear-waste repository in Nevada in place (though not yet approved), one promising use for these underground storage tanks is as a temporary waystation for waste destined for the Nevada repository. However, without a reasonable understanding of the chemical reactions going on within the tanks, transporting waste in and out of the tanks has been deemed to be unsafe. One hazard associated with such storage mechanisms is explosion of flammable gases produced within the tank. Within many of the storage tanks is a sludge layer. This layer, which is a mixture of liquid and solids, contains most of the radioactive material. Radioactive decay and its associated heat can produce several flammable materials within this layer. Two components of particular concern are hydrogen (H2) and nitrous oxide (N2O), since they are highly volatile in the gaseous phase. Though the tanks have either forced or natural convection systems to vent these gases, the possibility of an explosion still exists. Measurements of these gases are taken in several ways. Continuous measurements are taken in the headspace, which is the layer between the tank ceiling and the liquid (supernatant) or sludge layer below. In tanks where a supernatant layer sits atop the sludge layer, there are often rollovers or gas release events (GREs), where a large chunk of sludge, after attaining a certain void fraction, becomes buoyant, rising through the supernatant and releasing its associated gas composition to the headspace. Such changes trigger a sensor, and thus measurements are also taken at that time. Lastly, a retained gas sample (RGS) can be taken from either the supernatant or sludge layer. Such a core sample is quite expensive, but can yield crucial data about the way gases are being produced in the sludge and convected through the supernatant. Unfortunately, the measurements from these three populations do not seem to match. In particular, the ratio r = [N2O]/[H2] varies from population to population. r also varies from tank to tank, but this can more readily be explained in terms of the waste composition of each tank. Since H2 is more volatile than N2O (and since there are more sources of oxygen in the headspace), lower values of r correspond to more hazardous situations. This variance in r is troubling, since we need to be able to explain why certain values of r are lower (and hence more dangerous) in certain areas of the tank. In this report we examine the data from three tanks. We first verify that the differences in r among populations is significant. We then postulate several mechanisms which could explain such a difference

Study of contamination sensors. Volume I - Executive summary report

Design criteria for automatic remotely indicating fluid contamination sensors, monitors, counters, and recorders and for sampling equipment and technique

Precipitation Monitoring at Yucca Mountain

This work will be conducted under Task ORD-FY04-007, “Precipitation Monitoring at Yucca Mountain”. The objective of this task is to measure, with known accuracy, the accumulation and timing of precipitation around Yucca Mountain using tipping bucket rain gauges. The data are used as part of the overall work supporting the net infiltration modeling Analysis Model Report, Simulation of Net Infiltration for Modern and Potential Future Climates, and the Performance Confirmation Plan. This work is subject to UCCSN QA program requirements. This SIP presents an independent confirmatory study supporting previously gathered information

Comparative analysis of solar power satellite systems to support a moon base

This paper compares different concepts for a space-based power system to support a lunar base: a solar power satellite (SPS) with a microwave wireless power transmission system (WPT), a hybrid configuration where two solar reflector satellites (SRS) fly in formation with the SPS and concentrate sunlight onto the SPS, and the CASSIOPeiA SPS system. Sizing of the transmitting and receiving antennae is conducted for a WPT concept utilising high frequency microwaves. Design of the microwave generator is based on gyrotron technology, with parabolic reflectors, and an array of rectifying patch antennae. The WPT solution consists of a number of satellites with solar arrays and transmission capabilities to provide continuous power to the receiving array. Solar reflectors alleviate the issue of day-night cycles, for ground-based solar arrays, by providing constant sunlight. This concept could be extended by increasing the irradiance provided by the reflecting satellite, thus decreasing the size of the ground solar array required. However, reflective satellites struggle with efficiency stemming from the size of the footprint they create, which is dependent on the angular subtense of the Sun. This paper demonstrates that a hybrid design, utilizing both the reflector satellites and the WPT, would provide the greatest power to weight ratio - decreasing the size of the solar array required. An important aspect in the effectiveness of solar powered satellites are their distance from the ground receiver, determined directly by their orbit. Smaller orbits allow for reduced distances between the satellite and ground; reducing receiver sizes. However, larger orbits increase transmission windows, reducing the required energy transfer rate. Another important consideration is the stability of the orbit. Stability is affected by the Solar Radiation Pressure, the gravitational pull of the Earth, and the effects of the non-spherical gravity field of the Moon. Thus, when designing the orbit, these effects have been considered alongside the trade-off between larger and smaller orbits. The solutions have been scaled and compared to the CASSIOPeiA concept architecture of a similar nature which has been investigated to demonstrate the effectiveness of the concept provided

Telephone-Based versus In-Person Delivery of Cognitive Behavioral Treatment for Veterans with Chronic Multisymptom Illness: A Controlled, Randomized Trial

Background:The goal of this randomized clinical trial was to examine the efficacy of a cognitive behavioral stress reduction treatment for reducing disability among veterans with chronic multisymptom illness (CMI).Method: Veterans (N=128) who endorsed symptoms of CMI were randomized to: usual care (n=43), in-person (n=42) or telephone-delivered cognitive behavioral stress management (n=43). Assessments were conducted at baseline, three months, and twelve months. The primary outcome was limitation in roles at work and home (i.e., ‘role physical’). Reductions in catastrophizing cognitions were evaluated as a mechanism of action. Results: Intent-to-treat analyses showed no statistically significant main effect (F(2, 164)=.58, p=.56) or interaction effect (F(4,164)=.94, p=.45) for role physical. Over time, veterans improved in their physical function (F(2,170)=5.34, p2partial=.06), PTSD symptoms (F(2,170)=9.39, p2partial=.10), depressive symptoms (F(2,170)=10.81, p2partial=.11), and physical symptoms (F(2, 172)=12.65, p2partial=.13), but these improvements did not differ across study arms over time. Completer analyses yielded similar results. There were no differences in catastrophizing between arms. Conclusion: Findings suggest stress reduction may not be the right target for improving disability among veterans with CMI. Veterans with CMI may need intervention that directly impacts medical self-management to improve disability

A Two-way Coupled Polydispersed Simulation of Bubbly Flow Beneath a Plunging Liquid Jet

ABSTRACT Plunging liquid jets are commonly encountered in nature and are widely used in industrial applications (e.g., in waterfalls, waste-water treatment, the oxygenation of chemical liquids, etc.). Despite numerous experimental studies that have been devoted to this interesting problem, there have been very few two-phase flow simulations. The main difficulty is the lack of a quantitative model to simulate the air entrainment process, which plays a critical role in this problem. In this paper, we present a computational multiphase fluid dynamics (CMFD) approach for solving this problem. The main ingredients of this approach are a comprehensive subgrid air entrainment model that predicts the rate and location of the air entrainment and a two-fluid transport model in which bubbles of different sizes are modeled as a continuum fluid. Using this approach, a Reynolds-averaged Navier Stokes (RaNS) two-way coupled two-phase flow simulation of a plunging liquid jet with a diameter of 24mm and a liquid jet velocity around 3.5m/s was performed. We analyzed the simulated void fraction and bubble count rate profiles at three different depths beneath the average free surface, and compared them with experimental data. We observed good agreement at all locations

The Effects of Nicotine in the Neonatal Quinpirole Rodent Model of Psychosis: Neural Plasticity Mechanisms and Nicotinic Receptor Changes

Neonatal quinpirole (NQ) treatment to rats increases dopamine D2 receptor sensitivity persistent throughout the animal’s lifetime. In Experiment 1, we analyzed the role of α7 and α4β2 nicotinic receptors (nAChRs) in nicotine behavioral sensitization and on the brain-derived neurotrophic factor (BDNF) response to nicotine in NQ- and neonatally saline (NS)-treated rats. In Experiment 2, we analyzed changes in α7 and α4β2 nAChR density in the nucleus accumbens (NAcc) and dorsal striatum in NQ and NS animals sensitized to nicotine. Male and female Sprague-Dawley rats were neonatally treated with quinpirole (1 mg/kg) or saline from postnatal days (P)1–21. Animals were given ip injections of either saline or nicotine (0.5 mg/kg free base) every second day from P33 to P49 and tested on behavioral sensitization. Before each injection, animals were ip administered the α7 nAChR antagonist methyllycaconitine (MLA; 2 or 4 mg/kg) or the α4β2 nAChR antagonist dihydro beta erythroidine (DhβE; 1 or 3 mg/kg). Results revealed NQ enhanced nicotine sensitization that was blocked by DhβE. MLA blocked the enhanced nicotine sensitization in NQ animals, but did not block nicotine sensitization. NQ enhanced the NAcc BDNF response to nicotine which was blocked by both antagonists. In Experiment 2, NQ enhanced nicotine sensitization and enhanced α4β2, but not 7, nAChR upregulation in the NAcc. These results suggest a relationship between accumbal BDNF and α4β2 nAChRs and their role in the behavioral response to nicotine in the NQ model which has relevance to schizophrenia, a behavioral disorder with high rates of tobacco smoking

High-resolution, H band Spectroscopy of Be Stars with SDSS-III/APOGEE: I. New Be Stars, Line Identifications, and Line Profiles

APOGEE has amassed the largest ever collection of multi-epoch, high-resolution (R~22,500), H-band spectra for B-type emission line (Be) stars. The 128/238 APOGEE Be stars for which emission had never previously been reported serve to increase the total number of known Be stars by ~6%. We focus on identification of the H-band lines and analysis of the emission peak velocity separations (v_p) and emission peak intensity ratios (V/R) of the usually double-peaked H I and non-hydrogen emission lines. H I Br11 emission is found to preferentially form in the circumstellar disks at an average distance of ~2.2 stellar radii. Increasing v_p toward the weaker Br12--Br20 lines suggests these lines are formed interior to Br11. By contrast, the observed IR Fe II emission lines present evidence of having significantly larger formation radii; distinctive phase lags between IR Fe II and H I Brackett emission lines further supports that these species arise from different radii in Be disks. Several emission lines have been identified for the first time including ~16895, a prominent feature in the spectra for almost a fifth of the sample and, as inferred from relatively large v_p compared to the Br11-Br20, a tracer of the inner regions of Be disks. Unlike the typical metallic lines observed for Be stars in the optical, the H-band metallic lines, such as Fe II 16878, never exhibit any evidence of shell absorption, even when the H I lines are clearly shell-dominated. The first known example of a quasi-triple-peaked Br11 line profile is reported for HD 253659, one of several stars exhibiting intra- and/or extra-species V/R and radial velocity variation within individual spectra. Br11 profiles are presented for all discussed stars, as are full APOGEE spectra for a portion of the sample.Comment: accepted in A