Abstract. Many of the soils in the south-eastern US are characterized by an argillic, or clay horizon, that largely parallels the soil surface at depths ranging from a few centimeters to 100 cen-timeters. The degree to which these argillic horizons alter subsurface movement of infiltrated water is not well known. Interflow, or throughflow, is shallow lateral subsurface flow that moves over a horizon that restricts percolation. This research investigates how often and under what conditions a relatively deep (20-150+cm) argillic horizon on low slope (2-6%) hillsides causes interflow to oc-cur. Research is being conducted at the Savannah River Site, Aiken, South Carolina, on a small zero-order watershed. In the first phase of this research, a high resolution topographic map of the clay layer was developed. This map will be used to instrument designated “low” spots with max rise piezo-meters in order to determine if there is channelized subsurface flow. In situ conductivities of the clay layer and the surface horizons were measured using an Amoozegar meter, and bulk density samples were taken and measured. Along with soil topographic measurements, data-logging piezometers have been installed to measure the piezometric head above, in, and below the argillic horizon to further investigate interflow …

We report on a search for the supersymmetric partner of the bottom quark produced from gluino decays in data from 2.5 fb{sup -1} of integrated luminosity collected by the Collider Detector at Fermilab at {radical}s = 1.96 TeV. Candidate events are selected requiring two or more jets and large missing transverse energy. At least two of the jets are required to be tagged as originating from a b quark to enhance the sensitivity. The results are in good agreement with the prediction of the standard model processes, giving no evidence for gluino decay to sbottom quarks. This result constrains the gluino-pair-production cross section to be less than 40 fb at 95% credibility level for a gluino mass of 350 GeV/c{sup 2}.

As energy prices skyrocket and interest in alternative, clean energy sources builds, interest in nuclear energy has increased. This increased interest in nuclear energy has been termed the “Nuclear Renaissance”. The performance of nuclear fuels, fuels and reactor materials and waste products are becoming a more important issue as the potential for designing new nuclear reactors is more immediate. The Idaho National Laboratory (INL) Materials and Fuels Complex (MFC) Analytical Laboratory Hot Cells (ALHC) are rising to the challenge of characterizing new reactor materials, byproducts and performance. The ALHC is a facility located near Idaho Falls, Idaho at the INL Site. It was built in 1958 as part of the former Argonne National Laboratory West Complex to support the operation of the second Experimental Breeder Reactor (EBR-II). It is part of a larger analytical laboratory structure that includes wet chemistry, instrumentation and radiochemistry laboratories. The purpose of the ALHC is to perform analytical chemistry work on highly radioactive materials. The primary work in the ALHC has traditionally been dissolution of nuclear materials so that less radioactive subsamples (aliquots) could be transferred to other sections of the laboratory for analysis. Over the last 50 years though, the capabilities within the ALHC …

We present a measurement of the t{bar t} differential cross section with respect to the t{bar t} invariant mass, d{sigma}/dM{sub t{bar t}}, in p{bar p} collisions at {radical}s = 1.96 TeV using an integrated luminosity of 2.7 fb{sup -1} collected by the CDF II experiment. The t{bar t} invariant mass spectrum is sensitive to a variety of exotic particles decaying into t{bar t} pairs. The result is consistent with the standard model expectation, as modeled by PYTHIA with CTEQ5L parton distribution functions.

Annihilation of cosmologically distributed dark matter is predicted to produce a potentially observable flux of high energy photons. Neglecting the contribution from local structure, this signal is predicted to be virtually uniform on the sky and, in order to be identified, must compete with various extragalactic backgrounds. We focus here on unresolved blazars and discuss several techniques for separating the dark matter signal from this background. First, the spectral shapes of the signal and background are expected to differ, a feature which can be exploited with the Fisher Matrix formalism. Second, in any given angular pixel, the number of photons from blazars is drawn from a distribution which is far from Poisson. A knowledge of this distribution enhances one's ability to extract the dark matter signal, while ignorance of it can lead to the introduction of a large systematic error.

The sensitivity of two specific types of radionuclide detectors for conducting an on-board search in the maritime environment was evaluated using Monte Carlo simulation implemented in AVERT{reg_sign}. AVERT{reg_sign}, short for the Automated Vulnerability Evaluation for Risk of Terrorism, is personal computer based vulnerability assessment software developed by the ARES Corporation. The sensitivity of two specific types of radionuclide detectors for conducting an on-board search in the maritime environment was evaluated using Monte Carlo simulation. The detectors, a RadPack and also a Personal Radiation Detector (PRD), were chosen from the class of Human Portable Radiation Detection Systems (HPRDS). Human Portable Radiation Detection Systems (HPRDS) serve multiple purposes. In the maritime environment, there is a need to detect, localize, characterize, and identify radiological/nuclear (RN) material or weapons. The RadPack is a commercially available broad-area search device used for gamma and also for neutron detection. The PRD is chiefly used as a personal radiation protection device. It is also used to detect contraband radionuclides and to localize radionuclide sources. Neither device has the capacity to characterize or identify radionuclides. The principal aim of this study was to investigate the sensitivity of both the RadPack and the PRD while being used under controlled conditions …

In order to demonstrate the feasibility of geological disposal of spent CANDU fuel in Canada, a safety assessment was performed for a hypothetical repository in the Canadian Shield. The assessment shows that such repository would meet international criteria for dose rate; however, uncertainties in the assumed evolution of the repository were identified. Such uncertainties could be resolved by the consideration of coupled Thermal-Hydro-Mechanical-Chemical (THMC) processes. In Task A of the DECOVALEX-THMC project, THM models were developed within the framework of the theory of poroelasticity. Such model development was performed in an iterative manner, using experimental data from laboratory and field tests. The models were used to perform near-field simulations of the evolution of the repository in order to address the above uncertainties. This paper presents the definition and rationale of task A and the results of the simulations. From a repository safety point of view, the simulations predict that the maximum temperature would be well below the design target of 100 C, however the load on the container can marginally exceed the design value of 15 MPa. However, the most important finding from the simulations is that a rock damage zone could form around the emplacement borehole. Such damage zone …

The Idaho National Laboratory (INL) currently does not have the necessary capabilities to process all remote-handled wastes resulting from the Laboratory’s nuclear-related missions. Over the years, various U.S. Department of Energy (DOE)-sponsored programs undertaken at the INL have produced radioactive wastes and other materials that are categorized as remote-handled (contact radiological dose rate > 200 mR/hr). These materials include Spent Nuclear Fuel (SNF), transuranic (TRU) waste, waste requiring geological disposal, low-level waste (LLW), mixed waste (both radioactive and hazardous per the Resource Conservation and Recovery Act [RCRA]), and activated and/or radioactively-contaminated reactor components. The waste consists primarily of uranium, plutonium, other TRU isotopes, and shorter-lived isotopes such as cesium and cobalt with radiological dose rates up to 20,000 R/hr. The hazardous constituents in the waste consist primarily of reactive metals (i.e., sodium and sodium-potassium alloy [NaK]), which are reactive and ignitable per RCRA, making the waste difficult to handle and treat. A smaller portion of the waste is contaminated with other hazardous components (i.e., RCRA toxicity characteristic metals). Several analyses of alternatives to provide the required remote-handling and treatment capability to manage INL’s remote-handled waste have been conducted over the years and have included various options ranging from modification of …

The U.S. Department of Energy (DOE), National Nuclear Security Administration Nevada Site Office Environmental Management Program is responsible for carrying out the disposal of on-site and off-site generated low-level radioactive waste (LLW) and low-level radioactive mixed waste (MW) at the Nevada Test Site (NTS). Core elements of this mission are ensuring safe and cost-effective disposal while protecting workers, the public, and the environment. This paper focuses on the impacts of new policies, processes, and opportunities at the NTS related to LLW and MW. Covered topics include: the first year of direct funding for NTS waste disposal operations; zero tolerance policy for non-compliant packages; the suspension of mixed waste disposal; waste acceptance changes; DOE Consolidated Audit Program (DOECAP) auditing; the 92-Acre Area closure plan; new eligibility requirements for generators; and operational successes with unusual waste streams.