One of the most challenging tasks faced by environmental engineers is cost effective hydraulic and hydrochemical characterization of a fractured bedrock aquifer by means of exploratory wellbores. To address this problem, a new borehole fluid logging method for rapidly and efficiently determining the vertical distribution of hydraulic conductivity in fractured bedrock aquifers has been developed. This new technique was recently applied near two active landfills in southern New England. The technique involves replacing the standing column of water in a borehole with a uniformly deionized fluid, and then profiling the changes in fluid electrical conductivity in the borehole. These changes occur when the contrasting formation water is drawn back into the borehole by continuous low flow rate pumping or by slug testing. A downhole wireline water-quality tool, which simultaneously measures fluid electrical conducivity, temperature, pH and oxidation-reduction potential (Eh), was employed to profile the physical/chemical changes of the ``emplaced`` fluid. The numerical code BORE, was employed to determine the inflow parameters and fracture-specific fluid electrical conducivity for the hydraulically conductive fractures. Straddle packer testing at 10-foot intervals was conducted to confirm the slug testing results. Some discrepancies were encountered which can be explained by accounting for the volume of formation …

A computer model for simulating the explosive dispersal of a fuel agent in the far-field regime is described and is applied to a wide variety of initial conditions to judge their effect upon the resulting fuel/air cloud. This work was directed toward modeling the dispersal process associated with Fuel-Air-Explosives devices. The far-field dispersal regime is taken to be that time after the initial burster charge detonation in which the shock forces no longer dominate the flow field and initial canister and fuel mass breakup has occurred. The model was applied to a low vapor pressure fuel, a high vapor pressure fuel and a solid fuel. A strong dependence of the final cloud characteristics upon the initial droplet size distribution was demonstrated. The predicted fuel-air clouds were highly non-uniform in concentration. 18 refs., 86 figs., 4 tabs.

This report summarizes progress on OHER human health, biological, general life sciences, and medical applications research programs conducted at PNL in FY 1989. The research develops the knowledge and scientific principles necessary to identify, understand, and anticipate the long-term health consequences of energy-related radiation and chemicals. Our continuing emphasis is to decrease the uncertainty of health risk estimates from existing and developing energy-related technologies through an increased understanding of how radiation and chemicals cause biological damage. The sequence of this report of PNL research reflects the OHER programmatic structure. The first section, on human health research, concerns statistical and epidemiological studies for assessing health risks. The next section contains reports of biological research in laboratory animals and in vitro cell systems, including research with radionuclides and chemicals. The general life sciences research section reports research conducted for the OHER human genome research program, and the medical applications section summarizes commercial radioisotope production and distribution activities at DOE facilities. 6 refs., 50 figs., 35 tabs.

This report is a summary of the environmental status of the Hanford Site in 1989. It includes descriptions of the Site and its mission, the status of compliance with environmental regulations, planning and activities to accomplish compliance, environmental protection and restoration activities, and environmental monitoring. 97 refs., 67 figs., 14 tabs.

One of the most challenging tasks faced by environmental engineers is cost effective hydraulic and hydrochemical characterization of a fractured bedrock aquifer by means of exploratory wellbores. To address this problem, a new borehole fluid logging method for rapidly and efficiently determining the vertical distribution of hydraulic conductivity in fractured bedrock aquifers has been developed. This new technique was recently applied near two active landfills in southern New England. The technique involves replacing the standing column of water in a borehole with a uniformly deionized fluid, and then profiling the changes in fluid electrical conductivity in the borehole. These changes occur when the contrasting formation water is drawn back into the borehole by continuous low flow rate pumping or by slug testing. A downhole wireline water-quality tool, which simultaneously measures fluid electrical conducivity, temperature, pH and oxidation-reduction potential (Eh), was employed to profile the physical/chemical changes of the emplaced'' fluid. The numerical code BORE, was employed to determine the inflow parameters and fracture-specific fluid electrical conducivity for the hydraulically conductive fractures. Straddle packer testing at 10-foot intervals was conducted to confirm the slug testing results. Some discrepancies were encountered which can be explained by accounting for the volume of formation …

It has been demonstrated that the H{sup -} output current from a small multicusp source can be substantially enhanced if the hydrogen plasma is seeded with barium. Operating with a barium washer insert at the extraction aperture, it is found that the extractable H{sup -} current is increased by a factor of three if the insert bias potential is optimized. By use of a mixture of xenon and hydrogen gas, it is further demonstrated that the positive hydrogen ions are responsible for the observed H{sup -} enhancement.

A system for the detection and measurement of indoor radon progeny activity-weighted size distributions (particle size, d{sub p} > 0.5 nm) and concentration levels has been developed. The system is microcomputer-controlled and involves a combination of multiple wire screen (Graded Screen Array) sampler-detector units operated in parallel. The radioactivity sampled in these units permits the estimation of the radon progeny activity-weighted size distributions and concentration levels on a semi-continuous basis. This paper presents details of the system and describes various stages in the development of the system. Results of field measurements in a residential environment are presented to illustrate the resolution, sensitivity and capabilities of the measurement system. 16 refs., 4 figs., 1 tab.

This report describes the Offsite Radiation Safety Program conducted during 1989 by the Environmental Protection Agency's (EPA's) Environmental Monitoring Systems Laboratory-Las Vegas (EMSL-LV). This laboratory operates an environmental radiation monitoring program in the region surrounding the Nevada Test Site (NTS) and at former test sites in Alaska, Colorado, Mississippi, Nevada, and New Mexico. The surveillance program is designed to measure levels, and trends of radioactivity, if present, in the environment surrounding testing areas to ascertain whether the testing is in compliance with existing radiation protection standards, and to take action to protect the health and well being of the public in the event of any accidental release of radioactive contaminants. Offsite levels of radiation and radioactivity are assessed by sampling milk, water, and air; by deploying thermoluminescent dosimeters (TLDs) and using pressurized ion chambers (PICs); and by biological monitoring of both animals and humans. To implement protective actions, provide immediate radiation monitoring, and obtain environmental samples rapidly after any release of radioactivity, personnel with mobile monitoring equipment are placed in areas downwind from the test site prior to each test. Comparison of the measurements and sample analysis results with background levels and with appropriate standards and regulations indicated that there …