Portsmouth Gaseous Diffusion Plant expansion, Piketon, Ohio. Volume 2. Draft environmental statement

International Nuclear Information System (INIS)

1976-06-01

The need for additional uranium enrichment facilities and the environmental impacts of the add-on gaseous diffusion plant proposed for the Portsmouth Gaseous Diffusion Plant are discussed. A detailed description of the proposed facilities is included and unavoidable adverse environmental effects, possible alternatives, and anticipated benefits from the proposed facilities are considered. The flora and fauna of the area are tabulated and possible effects of air and water pollution on aquatic and terrestrial ecosystems are postulated. The extent of anticipated noise impact on the vicinity and the anticipated extent of civic envolvement are discussed

Uranium enrichment export control guide: Gaseous diffusion

Energy Technology Data Exchange (ETDEWEB)

1989-09-01

This document was prepared to serve as a guide for export control officials in their interpretation, understanding, and implementation of export laws that relate to the Zangger International Trigger List for gaseous diffusion uranium enrichment process components, equipment, and materials. Particular emphasis is focused on items that are especially designed or prepared since export controls are required for these by States that are party to the International Nuclear Nonproliferation Treaty.

Vibration signature analysis of compressors in the gaseous diffusion process for uranium enrichment

International Nuclear Information System (INIS)

Harbarger, W.B.

1975-01-01

Continuous operation of several thousand axial-flow and centrifugal compressors is vital to the gaseous diffusion process for uranium enrichment. Vibration signature analysis using a minicomputer-based Fast Fourier Transform Analyzer is being applied to the evaluation and surveillance of compressor performance at the Portsmouth Gaseous Diffusion Plant. Three areas of application include: (1) new blade design and prototype compressor evaluation; (2) corrective and preventive maintenance of machinery components; and (3) evaluation of machinery health. The present system is being used to monitor signals from accelerometers mounted on the load-bearing housings of 16 on-line compressors. These signals are transmitted by hard-wire to the analyzer for daily monitoring. A program for expansion of this system to monitor more than a thousand compressors and automation of the signature comparison process is planned for all three gaseous diffusion plants operated for the United States Energy Research and Development Administration. (auth)

First report on the Oak Ridge K-25 Site Biological Monitoring and Abatement Program for Mitchell Branch

Energy Technology Data Exchange (ETDEWEB)

Smith, J.G. [ed.; Adams, S.M.; Kszos, L.A.; Ryon, M.G.; Southworth, G.R.; Loar, J.M.

1993-08-01

A modified National Pollutant Discharge Elimination System permit was issued to the Oak Ridge Gaseous Diffusion Plant (now referred to as the Oak Ridge K-25 Site) on September 11, 1986. The Oak Ridge K-25 Site is a former uranium-enrichment production facility, which is currently managed by Martin Marietta Energy Systems, Inc. for the US Department of Energy. As required in Part III (L) of that permit, a plan for the biological monitoring of Mitchell Branch (K-1700 stream) was prepared and submitted for approval to the US Environmental Protection Agency and the Tennessee Department of Environment and Conservation [formerly the Tennessee Department of Health and Environment (Loar et al. 1992b)]. The K-25 Site Biological Monitoring and Abatement Program (BMAP) described biomonitoring activities that would be conducted over the duration of the permit. Because it was anticipated that the composition of existing effluent streams entering Mitchell Branch would be altered shortly after the modified permit was issued, sampling of the benthic invertebrate and fish communities (Task 4 of BMAP) was initiated in August and September 1986 respectively.

First report on the Oak Ridge K-25 Site Biological Monitoring and Abatement Program for Mitchell Branch

International Nuclear Information System (INIS)

Smith, J.G.; Adams, S.M.; Kszos, L.A.; Ryon, M.G.; Southworth, G.R.; Loar, J.M.

1993-08-01

A modified National Pollutant Discharge Elimination System permit was issued to the Oak Ridge Gaseous Diffusion Plant (now referred to as the Oak Ridge K-25 Site) on September 11, 1986. The Oak Ridge K-25 Site is a former uranium-enrichment production facility, which is currently managed by Martin Marietta Energy Systems, Inc. for the US Department of Energy. As required in Part III (L) of that permit, a plan for the biological monitoring of Mitchell Branch (K-1700 stream) was prepared and submitted for approval to the US Environmental Protection Agency and the Tennessee Department of Environment and Conservation [formerly the Tennessee Department of Health and Environment (Loar et al. 1992b)]. The K-25 Site Biological Monitoring and Abatement Program (BMAP) described biomonitoring activities that would be conducted over the duration of the permit. Because it was anticipated that the composition of existing effluent streams entering Mitchell Branch would be altered shortly after the modified permit was issued, sampling of the benthic invertebrate and fish communities (Task 4 of BMAP) was initiated in August and September 1986 respectively

Lung Cancer Mortality among Uranium Gaseous Diffusion Plant Workers: A Cohort Study 1952–2004

Directory of Open Access Journals (Sweden)

LW Figgs

2013-07-01

Full Text Available Background: 9%–15% of all lung cancers are attributable to occupational exposures. Reports are disparate regarding elevated lung cancer mortality risk among workers employed at uranium gaseous diffusion plants. Objective: To investigate whether external radiation exposure is associated with lung cancer mortality risk among uranium gaseous diffusion workers. Methods: A cohort of 6820 nuclear industry workers employed from 1952 to 2003 at the Paducah uranium gaseous diffusion plant (PGDP was assembled. A job-specific exposure matrix (JEM was used to determine likely toxic metal exposure categories. In addition, radiation film badge dosimeters were used to monitor cumulative external ionizing radiation exposure. International Classification for Disease (ICD codes 9 and 10 were used to identify 147 lung cancer deaths. Logistic and proportional hazards regression were used to estimate lung cancer mortality risk. Results: Lung cancer mortality risk was elevated among workers who experienced external radiation >3.5 mrem and employment duration >12 years. Conclusion: Employees of uranium gaseous diffusion plants carry a higher risk of lung cancer mortality; the mortality is associated with increased radiation exposure and duration of employment.

Radioactive effluents, Portsmouth Gaseous Diffusion Plant, calendar year 1982

International Nuclear Information System (INIS)

Acox, T.A.; Hary, L.F.; Klein, L.S.

1983-03-01

Radioactive discharges from the Portsmouth Gaseous Diffusion Plant are discussed and tabulated. Tables indicate both the location of the discharge and the nuclides discharged. All discharges for 1982 are well below the Radioactive Concentration Guide limits specified in DOE Order 5480.1, Chapter XI. 1 figure

Plant air systems safety study: Portsmouth Gaseous Diffusion Plant

International Nuclear Information System (INIS)

1982-05-01

The Portsmouth Gaseous Diffusion Plant Air System facilities and operations are reviewed for potential safety problems not covered by standard industrial safety procedures. Information is presented under the following section headings: facility and process description (general); air plant equipment; air distribution system; safety systems; accident analysis; plant air system safety overview; and conclusion

EURODIF: the uranium enrichment by gaseous diffusion

International Nuclear Information System (INIS)

Rougeau, J.P.

1981-01-01

During the seventies the nuclear power programme had an extremely rapid growth rate which entailed to increase the world uranium enrichment capacity. EURODIF is the largest undertaking in this field. This multinational joint venture built and now operates and enrichment plant using the gaseous diffusion process at Tricastin (France). This plant is delivering low enriched uranium since two years and has contracted about 110 million SWU's till 1990. Description, current activity and prospects are given in the paper. (Author) [pt

Methodology for assessment of safety risk due to potential accidents in US gaseous diffusion plants

International Nuclear Information System (INIS)

Turner, J.H.; O'Kain, D.U.

1991-01-01

Gaseous diffusion plants that operate in the United States represent a unique combination of nuclear and chemical hazards. Assessing and controlling the health, safety, and environmental risks that can result from natural phenomena events, process upset conditions, and operator errors require a unique methodology. Such a methodology has been developed for the diffusion plants and is being utilized to assess and control the risk of operating the plants. A summary of the methodology developed to assess the unique safety risks at the US gaseous diffusion plants is presented in this paper

On-line vibration and analysis system at the Paducah Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Herricks, D.M.; Strunk, W.D.

1987-11-01

The enrichment facility in Paducah, KY uses a unique hard-wired vibration monitoring and analysis system for gaseous diffusion equipment. The axial flow and centrifugal flow compressors used in uranium enrichment range in size from 6 feet in diameter to less than one foot in diameter. These compressors must operate smoothly and safely, without breech of containment, since the working fluid of gaseous diffusion is gaseous UF 6 . The condition of 1925 compressors is monitored by use of the 2500 point vibration analysis system. Since the failure mechanisms of the compressors are well known and documented, only one accelerometer per machine is needed for most machines. The system is completely automated and can generate spectra or broadband levels in either acceleration or velocity units. Levels are stored for historical review. The analyst can, via a custom telecommunications link, view and analyze data from all monitored points with an office PC. 4 figs

Aerial radiological survey of the area surrounding the Portsmouth Gaseous Diffusion Plant, Portsmouth, Ohio

International Nuclear Information System (INIS)

1979-09-01

An airborne radiological survey was conducted in July 1976. It was centered on the Portsmouth Gaseous Diffusion Plant. Two areas were surveyed: one 35 km 2 and the other 16 km 2 . Using Nal(Tl) scintillation detectors, measurements were made of the terrestrial gamma radiation over the areas with a series of north-south flight lines. The processed data indicated that on-site radioactivity was due to nuclear matterials currently or previously handled, processed, or stored. Off-site activities were found to be due wholly to the naturally occurring 40 K, the 238 U chain, and thorium chain gamma emitters

Site Characterization Report ORGDP Diffusion Facilities Permanent Shutdown K-700 Power House and K-27 Switch Yard/Switch House

Energy Technology Data Exchange (ETDEWEB)

Thomas R.J., Blanchard R.D.

1988-06-13

The K-700 Power House area, initially built to supply power to the K-25 gaseous diffusion plant was shutdown and disassembled in the 1960s. This shutdown was initiated by TVA supplying economical power to the diffusion plant complex. As a result of world wide over production of enriched, reactor grade U{sup 235}, the K-27 switch yard and switch house area was placed in standby in 1985. Subsequently, as the future production requirements decreased, the cost of production increased and the separation technologies for other processes improved, the facility was permanently shutdown in December, 1987. This Site Characterization Report is a part of the FY-88 engineering Feasibility Study for placing ORGDP Gaseous Diffusion Process facilities in 'Permanent Shutdown'. It is sponsored by the Department of Energy through Virgil Lowery of Headquarters--Enrichment and through Don Cox of ORO--Enrichment Operations. The primary purpose of these building or site characterization reports is to document, quantify, and map the following potential problems: Asbestos; PCB containing fluids; Oils, coolants, and chemicals; and External contamination. With the documented quantification of the concerns (problems) the Engineering Feasibility Study will then proceed with examining the potential solutions. For this study, permanent shutdown is defined as the securing and/or conditioning of each facility to provide 20 years of safe service with minimal expenditures and, where feasible, also serving DOE's needs for long-term warehousing or other such low-risk use. The K-700 power house series of buildings were either masonry construction or a mix of masonry and wood. The power generating equipment was removed and sold as salvage in the mid 1960s but the buildings and auxiliary equipment were left intact. The nine ancillary buildings in the power house area use early in the Manhattan Project for special research projects, were left intact minus the original special equipment

Direct measurement of gaseous activities by diffusion-in long proportional counter method

International Nuclear Information System (INIS)

Yoshida, M.; Yamamoto, T.; Wu, Y.; Aratani, T.; Uritani, A.; Mori, C.

1993-01-01

Direct measurement of gaseous activities by the diffusion-in long proportional counter method (DLPC method) was studied. The measuring time without end effect was estimated by observing the behavior of 37 Ar in the counter and was long enough to carry out the accurate activity measurement. The correction for wall effect was also examined on the basis of the measured and calculated correction factors. Among the tested gases of methane, P10 gas and propane, P10 gas was made clear to be a suitable counting gas for the DLPC method because of good diffusion properties and small wall effect. This method is quite effective for standardization of gaseous activities used for tracer experiments and calibration works of radioactive gas monitoring instruments. (orig.)

Portsmouth gaseous diffusion plant environmental monitoring report for calendar year 1975

International Nuclear Information System (INIS)

Martin, W.E.; Netzer, W.D.

1976-01-01

At the Portsmouth Gaseous Diffusion Plant the ambient atmosphere and all effluent streams are sampled and analyzed regularly for conformance to applicable environmental standards. Although neither the State of Ohio nor the federal government has established standards for fluorides in the ambient atmosphere or in vegetation, these parameters also are monitored because fluoride compounds are used extensively in the gaseous diffusion process. Radioactivity is measured in air, water, food, soil, and sediments; and radiation doses are calculated for the public. All public radiation doses are well within federal standards. Non-radioactive effluent parameters either comply with federal standards, or there are projects planned to allow compliance. A disposal facility to remove chromium from recirculating cooling water blowdown will begin operation in June 1976. Also, pH adjustment facilities for liquid effluents and electrostatic precipitators for a coal-fired steam plant are planned for the near future

Gaseous diffusion flames: simple structures and their interaction

Energy Technology Data Exchange (ETDEWEB)

Cavaliere, A. [Universita degli Studi Federico II, Naples (Italy). Dip. di Ingegneria Chimica; Ragucci, R. [Istituto di Ricerche sulla Combustione C,N.R., Naples (Italy)

2001-07-01

This is a synoptic overview of a selection of works dealing with single diffusive structures, with their mutual interaction in simple flows and their statistical modeling in complex flows. The focus is on reacting conditions pertaining to gaseous diffusion flames, but isothermal structures are also described when they are of some conceptual interest. This paper considers only few representative works for each subject, which are functional in explaining the key characteristics of the diffusive structures. The extension, given to single subjects, is not weighed according to the number of related publications but on the relevance to the basic understanding of the general framework concerning diffusion flames. One-dimensional structures are first discussed. They are ordered according to the number of balance equation terms needed for their description. Two-dimensional (2D) structures are then introduced following an order based on their convolution level. Some pioneering work on three-dimensional structures is further quoted. The temporal evolution of simple structures in quiescent or simple flowing 2D systems is considered. The latter case is exploited to present classification of diffusion-controlled mixing regimes. Modeling characterization approach of turbulent diffusion flames is also described in order to yield a self-sufficient didactic presentation. The approach based on the flame surface density model is specifically discussed because of its potential use in the determination of qualitative and quantitative features of simple diffusion flames. (author)

Tc-99 Decontamination From Heat Treated Gaseous Diffusion Membrane -Phase I

Energy Technology Data Exchange (ETDEWEB)

Oji, L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Wilmarth, B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Restivo, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Duignan, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-03-13

Uranium gaseous diffusion cascades represent a significant environmental challenge to dismantle, containerize and dispose as low-level radioactive waste. Baseline technologies rely on manual manipulations involving direct access to technetium-contaminated piping and materials. There is a potential to utilize novel thermal decontamination technologies to remove the technetium and allow for on-site disposal of the very large uranium converters. Technetium entered these gaseous diffusion cascades as a hexafluoride complex in the same fashion as uranium. Technetium, as the isotope Tc-99, is an impurity that follows uranium in the first cycle of the Plutonium and Uranium Extraction (PUREX) process. The technetium speciation or exact form in the gas diffusion cascades is not well defined. Several forms of Tc-99 compounds, mostly the fluorinated technetium compounds with varying degrees of volatility have been speculated by the scientific community to be present in these cascades. Therefore, there may be a possibility of using thermal desorption, which is independent of the technetium oxidation states, to perform an in situ removal of the technetium as a volatile species and trap the radionuclide on sorbent traps which could be disposed as low-level waste.

Preduction of the vibratory behaviour of a multistage gaseous diffusion plant

International Nuclear Information System (INIS)

Descleve, P.; Bertaut, C.; Briot, P.

1979-01-01

A study has been made to predict the vibratory behaviour of the rotating machinery of a gaseous diffusion plant starting from the results obtained for a single machine. TRICASTIN gaseous diffusion plant uses several hundred of enrichment stages but only three different sizes of machine are used. Each individual machine is a vertical assembly of a compressor heat exchanger and diffusion barriers, this column is supported on four lugs on a concrete slab. This slab must accomodate thermal expansion and is placed on neoprene pads. Due to the compactness of the system the mass of concrete is relatively small. Typically the mass of a machine of the intermediate size is 84 T, the mass of associated concrete is 55 T. Furthermore this supporting slab is flexible, meaning that a dynamic analysis of the slab shows several frequencies below the compressor rotational speed. Extensive dynamic tests have been conducted on a machine supported on a rigid foundation. These tests have shown that the main source of mechanical excitation was caused at 50 Hz by the unbalance of the electrical motor rotor. Then the problem remained to predict the behaviour of a group of twenty machines in the plant itself. (orig.)

Nuclear criticality safety aspects of gaseous uranium hexafluoride (UF6) in the diffusion cascade

International Nuclear Information System (INIS)

Huffer, J.E.

1997-04-01

This paper determines the nuclear safety of gaseous UF 6 in the current Gaseous Diffusion Cascade and auxiliary systems. The actual plant safety system settings for pressure trip points are used to determine the maximum amount of HF moderation in the process gas, as well as the corresponding atomic number densities. These inputs are used in KENO V.a criticality safety models which are sized to the actual plant equipment. The ENO V.a calculation results confirm nuclear safety of gaseous UF 6 in plant operations

An aerial radiological survey of the Portsmouth Gaseous Diffusion Plant and surrounding area, Portsmouth, Ohio

International Nuclear Information System (INIS)

1992-09-01

An aerial radiological survey was conducted from July 11--20, 1990, over an 83-square-kilometer (32-square-mile) area surrounding the Portsmouth Gaseous Diffusion Plant located near Portsmouth, Ohio. The survey was conducted at a nominal altitude of 91 meters (300 feet) with line spacings of 122 meters (400 feet). A contour map of the terrestrial gamma exposure rate extrapolated to 1 meter above ground level (AGL) was prepared and overlaid on an aerial photograph and a set of United States Geological Survey (USGS) topographic maps of the area. The terrestrial exposure rates varied from about 7 to 14 microroentgens per hour (μR/h) at 1 meter above the ground. Analysis of the data for man-made sources and for the uranium decay product, protactinium-234m ( 234m Pa), showed five sites within the boundaries of the Portsmouth Gaseous Diffusion Plant with elevated readings. Spectra obtained in the vicinity of the buildings at the Portsmouth Gaseous Diffusion Plant showed the presence of 234m Pa, a uranium-238 ( 238 U) decay product. In addition, spectral analysis of the data obtained over the processing plant facility showed gamma activity indicative of uranium-235 ( 234 U). No other man-made gamma ray emitting radioactive material was detected, either on or off the Portsmouth Gaseous Diffusion Plant property. Soil samples and pressurized ion chamber measurements were obtained at five different locations within the survey boundlaries to support the aerial data

Portsmouth Gaseous Diffusion Plant expansion: final environmental statement. Volume 1

Energy Technology Data Exchange (ETDEWEB)

1977-09-01

Volume 1 is comprised of chapters on: background and description; environmental impacts of add-on gaseous diffusion plant; unavoidable adverse environmental effects; alternatives; relationship between short-term uses and long-term productivity; relationship of program to land-use plans, policies, and controls; irreversible and irretrievable commitments of resources; cost-benefit analysis; and response to comment letters. (LK)

Portsmouth Gaseous Diffusion Plant expansion: final environmental statement. Volume 1

International Nuclear Information System (INIS)

1977-09-01

Volume 1 is comprised of chapters on: background and description; environmental impacts of add-on gaseous diffusion plant; unavoidable adverse environmental effects; alternatives; relationship between short-term uses and long-term productivity; relationship of program to land-use plans, policies, and controls; irreversible and irretrievable commitments of resources; cost-benefit analysis; and response to comment letters

A novel enhanced diffusion sampler for collecting gaseous pollutants without air agitation.

Science.gov (United States)

Pan, Xuelian; Zhuo, Shaojie; Zhong, Qirui; Chen, Yuanchen; Du, Wei; Cheng, Hefa; Wang, Xilong; Zeng, Eddy Y; Xing, Baoshan; Tao, Shu

2018-03-06

A novel enhanced diffusion sampler for collecting gaseous phase polycyclic aromatic hydrocarbons (PAHs) without air agitation is proposed. The diffusion of target compounds into a sampling chamber is facilitated by continuously purging through a closed-loop flow to create a large concentration difference between the ambient air and the air in the sampling chamber. A glass-fiber filter-based prototype was developed. It was demonstrated that the device could collect gaseous PAHs at a much higher rate (1.6 ± 1.4 L/min) than regular passive samplers, while the ambient air is not agitated. The prototype was also tested in both the laboratory and field for characterizing the concentration gradients over a short distance from the soil surface. The sampler has potential to be applied in other similar situations to characterize the concentration profiles of other chemicals.

Decommissioning of the gaseous diffusion plant at BNF plc Capenhurst in the UK

International Nuclear Information System (INIS)

Clements, D.W.; Cross, J.R.

1993-01-01

Since 1982, a gaseous diffusion plant located at the British Nuclear Fuels plc (BNFL) site at Capenhurst in the United Kingdom, has been undergoing decontamination, decommissioning, and dismantling. By March 1994, the decontamination and decommissioning activities will be complete with 99% of the materials used to construct the plant recycled to the environment as clean material. This paper describes the history of the decontamination, decommissioning, dismantling, and disposal program. Reference is made to the scale of the project and to the special techniques developed, particularly in the areas of size reduction, decontamination, and protection of personnel and the environment. The quantities of material involved that require decontamination and release levels for recycling materials in the U.K. metals market are discussed

Third report on the Oak Ridge K-25 Site Biological Monitoring and Abatement Program for Mitchell Branch

Energy Technology Data Exchange (ETDEWEB)

Hinzman, R.L. [ed.; Adams, S.M.; Ashwood, T.L. [Oak Ridge National Lab., TN (United States)] [and others

1995-08-01

As a condition of the modified National Pollutant Discharge Elimination System (NPDES) permit issued to the Oak Ridge Gaseous Diffusion Plant (ORGDP; now referred to as the Oak Ridge K-25 Site) on September 11, 1986, a Biological Monitoring and Abatement Program (BMAP) was developed for the receiving stream (Mitchell Branch or K-1700 stream). On October 1, 1992, a renewed NPDES permit was issued for the K-25 Site. A biological monitoring plan was submitted for Mitchell Branch, Poplar Creek, Poplar Creek Embayment of the Clinch River and any unnamed tributaries of these streams. The objectives of BMAP are to (1) demonstrate that the effluent limitations established for the Oak Ridge K-25 Site protect and maintain the use of Mitchell Branch for growth and propagation of fish and other aquatic life and (2) document the effects on stream biota resulting from operation of major new pollution abatement facilities, including the Central Neutralization Facility (CNF) and the Toxic Substances Control Act (TSCA) incinerator. The BMAP consists of four tasks: (1) toxicity monitoring; (2) bioaccumulation monitoring; (3) assessment of fish health; and (4) instream monitoring of biological communities, including benthic macroinvertebrates and fish. This document, the third in a series, reports on the results of the Oak Ridge K-25 Site BMAP; it describes studies that were conducted over various periods of time between June 1990 and December 1993, although monitoring conducted outside this time period is included, as appropriate.

Third report on the Oak Ridge K-25 Site Biological Monitoring and Abatement Program for Mitchell Branch

International Nuclear Information System (INIS)

Hinzman, R.L.

1995-08-01

As a condition of the modified National Pollutant Discharge Elimination System (NPDES) permit issued to the Oak Ridge Gaseous Diffusion Plant (ORGDP; now referred to as the Oak Ridge K-25 Site) on September 11, 1986, a Biological Monitoring and Abatement Program (BMAP) was developed for the receiving stream (Mitchell Branch or K-1700 stream). On October 1, 1992, a renewed NPDES permit was issued for the K-25 Site. A biological monitoring plan was submitted for Mitchell Branch, Poplar Creek, Poplar Creek Embayment of the Clinch River and any unnamed tributaries of these streams. The objectives of BMAP are to (1) demonstrate that the effluent limitations established for the Oak Ridge K-25 Site protect and maintain the use of Mitchell Branch for growth and propagation of fish and other aquatic life and (2) document the effects on stream biota resulting from operation of major new pollution abatement facilities, including the Central Neutralization Facility (CNF) and the Toxic Substances Control Act (TSCA) incinerator. The BMAP consists of four tasks: (1) toxicity monitoring; (2) bioaccumulation monitoring; (3) assessment of fish health; and (4) instream monitoring of biological communities, including benthic macroinvertebrates and fish. This document, the third in a series, reports on the results of the Oak Ridge K-25 Site BMAP; it describes studies that were conducted over various periods of time between June 1990 and December 1993, although monitoring conducted outside this time period is included, as appropriate

Method and apparatus for rapid adjustment of process gas inventory in gaseous diffusion cascades

International Nuclear Information System (INIS)

1980-01-01

A method is specified for the operation of a gaseous diffusion cascade wherein electrically driven compressors circulate a process gas through a plurality of serially connected gaseous diffusion stages to establish first and second countercurrently flowing cascade streams of process gas, one of the streams being at a relatively low pressure and enriched in a component of the process gas and the other being at a higher pressure and depleted in the same, and wherein automatic control systems maintain the stage process gas pressures by positioning process gas flow control valve openings at values which are functions of the difference between reference-signal inputs to the systems, and signal inputs proportional to the process gas pressures in the gaseous diffusion stages associated with the systems, the cascade process gas inventory being altered, while the cascade is operating, by simultaneously directing into separate process-gas freezing zones a plurality of substreams derived from one of the first and second streams at different points along the lengths thereof to solidify approximately equal weights of process gas in the zone while reducing the reference-signal inputs to maintain the positions of the control valves substantially unchanged despite the removal of process gas inventory via the substreams. (author)

Nuclear criticality safety aspects of gaseous uranium hexafluoride (UF{sub 6}) in the diffusion cascade

Energy Technology Data Exchange (ETDEWEB)

Huffer, J.E. [Parallax, Inc., Atlanta, GA (United States)

1997-04-01

This paper determines the nuclear safety of gaseous UF{sub 6} in the current Gaseous Diffusion Cascade and auxiliary systems. The actual plant safety system settings for pressure trip points are used to determine the maximum amount of HF moderation in the process gas, as well as the corresponding atomic number densities. These inputs are used in KENO V.a criticality safety models which are sized to the actual plant equipment. The ENO V.a calculation results confirm nuclear safety of gaseous UF{sub 6} in plant operations..

Scheduling the maintenance of gaseous diffusion and electric power distribution plants

International Nuclear Information System (INIS)

Chauvet, D.

1990-01-01

A computer aided scheduling applied to the maintenance of a uranium enrichment plant is presented. The plant exploits gaseous diffusion and electric power distribution plants, for which the operating conditions must be satisfied. The management and the execution of the maintenance actions are computer aided. Concerning the techniques, the cost, the safety and the scheduling actions were optimized [fr

Paducah Gaseous Diffusion Plant Annual Site Environmental Report for 1993

International Nuclear Information System (INIS)

1994-10-01

The purpose of this document is to summarize effluent monitoring and environmental surveillance results and compliance with environmental laws, regulations, and orders at the Paducah Gaseous Diffusion Plant (PGDP). Environmental monitoring at PGDP consists of two major activities: effluent monitoring and environmental surveillance. Effluent monitoring is direct measurement or the collection and analysis of samples of liquid and gaseous discharges to the environment. Environmental surveillance is direct measurement or the collection and analysis of samples of air, water, soil, foodstuff, biota, and other media. Environmental monitoring is performed to characterize and quantify contaminants, assess radiation exposures of members of the public, demonstrate compliance with applicable standards and permit requirements, and detect and assess the effects (if any) on the local environment. Multiple samples are collected throughout the year and are analyzed for radioactivity, chemical content, and various physical attributes

Determination of the separation factor of uranium isotopes by gaseous diffusion

International Nuclear Information System (INIS)

Bilous, O.; Counas, G.

1958-01-01

A 12-stage pilot separation cascade with a low output has been constructed to measure the separation factor of uranium isotopes by gaseous diffusion. The report describes some of the separation results obtained, and also provides information on the time necessary for equilibrium to be established and on the influence of various perturbations on the pressure profile in the cascade. (author) [fr

Control of technetium at the Portsmouth Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Saraceno, A.J.

1981-01-01

Technetium-99 entered the gaseous diffusion complex as a volatile impurity in recycled uranium that was fed to the Paducah Gaseous Diffusion Plant. Subsequently, it entered the Oak Ridge and Portsmouth cascades as an impurity in Paducah product feed. Most of the technetium was adsorbed on cascade equipment in increasingly high concentrations as it moved up the cascade. Since the low energy beta radiation produced by technetium cannot penetrate cascade equipment, it presents no significant hazard to workers as long as it remains inside of equipment. However, when equipment that contains high concentrations of technetium is opened for maintenance or change-out, precautions are taken to ensure worker safety. Traps containing activated alumina are used at the plant vent streams to limit radioactive emissions as far as possible. Annual vent stream emissions have been well below DOE limits. To allow continued compliance, other potential trapping agents have been tested. Several that limit emissions more effectively than activated alumina have been found. Other traps containing magnesium fluoride are used in the upper cascade to reduce the technetium concentration. Waste solutions from decontamination can also contain technetium. These solutions must either be stored for controlled discharge or treated to remove the technetium. To allow the latter, an ion exchange facility is being installed for operation by the end of FY-1982. Liquid discharges at Portsmouth have usually been less than 5% of the DOE imposed limits

Portsmouth Gaseous Diffusion Plant environmental monitoring report for calendar year 1981

International Nuclear Information System (INIS)

Acox, T.A.; Anderson, R.E.; Hary, L.F.; Klein, L.S.; Vausher, A.L.

1982-04-01

At the Portsmouth Gaseous Diffusion Plant all effluent streams are sampled regularly and analyzed to assess compliance with applicable environmental standards. Radioactivity is measured in air, water, food, soil, and sediments; and radiation doses to the public are calculated. All public radiation doses from process effluents are well within Department of Energy and US EPA standards. Non-radioactive effluents either presently comply with federal standards or will comply upon completion of planned projects. The environmental impact of effluents from cleaning and decontamination operations has been reduced through flow reduction and improved chemical treatment. CY-1981 was the first full year under a new National Pollutant Discharge. Elimination System (NPDES) permit for liquid effluents; compliance with the permit's discharge limits did not present any significant problems. Engineering is proceeding on projects to be constructed through 1985 to further reduce the impact of liquid effluents. A new licensed sanitary landfill utilizing the area fill method went into operation in July 1981. Although neither the State of Ohio nor the federal government has established standards for fluoride in the atmosphere or in vegetation, fluorides are monitored because they are used extensively in the gaseous diffusion process

Hierarchical optimization in isotope separation-gaseous diffusion: plant, cascade, stage, principles, and applications

Energy Technology Data Exchange (ETDEWEB)

Guais, J. C.

1975-09-01

The large scale system represented by a gaseous diffusion plant model, and its hierarchical mathematical structure are the reasons for a decomposition method, minimizing the total cost of enrichment. This procedure has been used for years in the optimization problems of the french projects.

Hierarchical optimization in isotope separation. Gaseous diffusion: plant, cascade, stage. Principles and applications

International Nuclear Information System (INIS)

Guais, J.C.

1975-01-01

The large scale system represented by a gaseous diffusion plant model, and its hierarchical mathematical structure are the reasons for a decomposition method, minimizing the total cost of enrichment. This procedure has been used for years in the optimization problems of the french projects [fr

Analysis of radiation fields in tomography on diffusion gaseous sound

International Nuclear Information System (INIS)

Bekman, I.N.

1999-01-01

Perspectives of application of equilibrium and stationary variants of diffusion tomography with radioactive gaseous sounds for spatial reconstruction of heterogeneous media in materials technology were considered. The basic attention were allocated to creation of simple algorithms of detection of sound accumulation on the background of monotonically varying concentration field. Algorithms of transformation of two-dimensional radiation field in three-dimensional distribution of radiation sources were suggested. The methods of analytical elongation of concentration field permitting separation of regional anomalies on the background of local ones and vice verse were discussed. It was shown that both equilibrium and stationary variants of diffusion tomography detect the heterogeneity of testing material, provide reduction of spatial distribution of elements of its structure and give an estimation of relative degree of defectiveness

Environmental Restoration Site-Specific Plan for the Portsmouth Gaseous Diffusion Plant, FY 93

International Nuclear Information System (INIS)

1993-01-01

The purpose of this Site-Specific Plan (SSP) is to describe past, present, and future activities undertaken to implement Environmental Restoration and Waste Management goals at the Portsmouth Gaseous Diffusion Plant (PORTS). The SSP is presented in sections emphasizing Environmental Restoration description of activities, resources, and milestones

Second report on the Oak Ridge K-25 Site Biological Monitoring and Abatement Program for Mitchell Branch

Energy Technology Data Exchange (ETDEWEB)

Smith, J.G. [ed.; Adams, S.M.; Hinzman, R.L.; Kszos, L.A.; Loar, J.M.; Peterson, M.J.; Ryon, M.G.; Southworth, G.R. [Oak Ridge National Lab., TN (United States); Crumby, W.D. [Automated Sciences Group, Inc., Oak Ridge, TN (United States)

1994-03-01

On September 11, 1986, a modified National Pollutant Discharge Elimination System permit was issued for the Oak Ridge Gaseous Diffusion Plant (ORGDP; now referred to as the Oak Ridge K-25 Site), a former uranium-enrichment production facility. As required in Part III of the permit, a Biological Monitoring and Abatement Program (BMAP) was developed for the biological monitoring of Mitchell Branch (K-1700 stream) and submitted for approval to the US EPA and the Tennessee Department of Environment and Conservation. The plan described biomonitoring activities that would be conducted over the duration of the permit. The objectives of the BMAP are to demonstrate that the effluent limitations established for the Oak Ridge K-25 Site protect and maintain the use of Mitchell Branch for growth and propagation of fish and other aquatic life, and to document the effects on stream biota resulting from operation of major new pollution abatement facilities. The BMAP consists of four tasks: ambient toxicity testing; bioaccumulation studies; biological indicator studies; and ecological surveys of stream communities, including benthic macroinvertebrates and fish. This document is the second in a series of reports presenting the results of the studies that were conducted over various periods of time between August 1987 and June 1990.

Natural phenomena evaluations of the K-25 site UF6 cylinder storage yards

International Nuclear Information System (INIS)

Fricke, K.E.

1996-01-01

The K-25 Site UF 6 cylinder storage yards are used for the temporary storage of UF 6 normal assay cylinders and long-term storage of other UF 6 cylinders. The K-25 Site UF 6 cylinder storage yards consist of six on-site areas: K-1066-B, K-1066-E, K-1066-F, K-1066-J, K-1066-K and K-1066-L. There are no permanent structures erected on the cylinder yards, except for five portable buildings. The operating contractor for the K-25 Site is preparing a Safety Analysis Report (SAR) to examine the safety related aspects of the K-25 Site UF 6 cylinder storage yards. The SAR preparation encompasses many tasks terminating in consequence analysis for the release of gaseous and liquid UF 6 , one of which is the evaluation of natural phenomena threats, such as earthquakes, floods, and winds. In support of the SAR, the six active cylinder storage yards were evaluated for vulnerabilities to natural phenomena, earthquakes, high winds and tornados, tornado-generated missiles, floods (local and regional), and lightning. This report summarizes those studies. 30 refs

Simulating Isotope Enrichment by Gaseous Diffusion

Science.gov (United States)

Reed, Cameron

2015-04-01

A desktop-computer simulation of isotope enrichment by gaseous diffusion has been developed. The simulation incorporates two non-interacting point-mass species whose members pass through a cascade of cells containing porous membranes and retain constant speeds as they reflect off the walls of the cells and the spaces between holes in the membranes. A particular feature is periodic forward recycling of enriched material to cells further along the cascade along with simultaneous return of depleted material to preceding cells. The number of particles, the mass ratio, the initial fractional abundance of the lighter species, and the time between recycling operations can be chosen by the user. The simulation is simple enough to be understood on the basis of two-dimensional kinematics, and demonstrates that the fractional abundance of the lighter-isotope species increases along the cascade. The logic of the simulation will be described and results of some typical runs will be presented and discussed.

Portsmouth Gaseous Diffusion Plant environmental report for 1992

International Nuclear Information System (INIS)

Horak, C.M.

1993-09-01

This calendar year (CY) 1992 annual report on environmental surveillance of the US Department of Energy's (DOE's) Portsmouth Gaseous Diffusion Plant (PORTS) and its environs consists of two parts: narrative, summaries, and conclusions (Part 1) and data presentation (Part 2). The objectives of this report are to: (1) report 1992 monitoring data for the installation and its environs that may have been affected by operations on the plant site, (2) provide reasonably detailed information about the plant site and plant operations, (3) provide detailed information on input and assumptions used in all calculations, (4) provide trend analyses (where appropriate) to indicate increases and decreases in environmental impact, and (5) provide general information on plant quality assurance

Reliability study: maintenance facilities Portsmouth Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Post, B.E.; Sikorski, P.A.; Fankell, R.; Johnson, O.; Ferryman, D.S.; Miller, R.L.; Gearhart, E.C.; Rafferty, M.J.

1981-08-01

A reliability study of the maintenance facilities at the Portsmouth Gaseous Diffusion Plant has been completed. The reliability study team analyzed test data and made visual inspections of each component contributing to the overall operation of the facilities. The impacts of facilities and equipment failures were given consideration with regard to personnel safety, protection of government property, health physics, and environmental control. This study revealed that the maintenance facilities are generally in good condition. After evaluating the physical condition and technology status of the major components, the study team made several basic recommendations. Implementation of the recommendations proposed in this report will help assure reliable maintenance of the plant through the year 2000

Portsmouth Gaseous Diffusion Plant Environmental report for 1990

Energy Technology Data Exchange (ETDEWEB)

Counce-Brown, D. (ed.)

1991-09-01

This calendar year 1990 annual report on environmental surveillance of the US Department of Energy's (DOE's) Portsmouth Gaseous Diffusion Plant (PORTS) and its environs consists of two parts: the summary, discussion, and conclusions (Part 1) and the data presentation (Part 2). The objectives of this report are as follows: report 1990 monitoring data for the installation and its environs that may have been affected by operations on the plant site, provide reasonably detailed information about the plant site and plant operations, provide detailed information on input and assumptions used in all calculations, provide trend analyses (when appropriate) to indicate increases and decreases in environmental impact, and provide general information on plant quality assurance.

Fundamental laws of separation by the gaseous diffusion process

International Nuclear Information System (INIS)

Bouligand, G.M.

1964-01-01

Using the Knudsen's law for the flow of each component of a gaseous mixture through a porous membrane, we derive the overall separation laws and the separation power for one stage of diffusion: Various types of stages differing by the geometrical configuration and the flow nature are considered. For the sake of simplicity physical phenomena causing a loss of separation efficiency are neglected. Computation show the advantages of counter-current type stage with one entering and two leaving flows. A more refined theory of separation can be derived with the same basis of this work. (author) [fr

Preliminary study of PCBs in raccoons living on or near the Paducah Gaseous Diffusion Plant, Kentucky

Energy Technology Data Exchange (ETDEWEB)

Halbrook, Richard S. [Southern Illinois Univ., Carbondale, IL (United States). Dept. of Zoology. Cooperative Wildlife Research Lab. Kentucky Research Consortium for Energy and Environment

2016-01-15

The “Ecological Monitoring at the Paducah Gaseous Diffusion Plant: Historical Evaluation and Guidelines for Future Monitoring” report (Halbrook, et al. 2007) recommended the raccoon as a species for study at the Paducah Gaseous Diffusion Plant (PGDP). This species was selected to fill data gaps in ecological resources and provide resource managers with knowledge that will be valuable in making decisions and implementing specific actions to safeguard ecological resources and reduce human exposure. The current paper reports results of a preliminary evaluation to establish protocols for collection of tissues and initial screening of polychlorinated biphenyls (PCBs) in raccoons collected near the PGDP. These data are useful in developing future more comprehensive studies.

A random walk approach to the diffusion of positrons in gaseous media

International Nuclear Information System (INIS)

Girardi-Schappo, M.; Tenfen, W.; Arretche, F.

2013-01-01

In this work, we present a random walk model to study the positron diffusion in gaseous media. The positron-atom interaction is described through positron-target cross sections. The main idea is to obtain how much energy a positron transfer to the environment atoms, through ionizations and electronic excitations until its annihilation, taking the ratio between each energetically available collision channel to the total one as the probability for each process to occur. As a first application, we studied how the positron diffuse in gases of helium, neon, argon and their mixtures. To characterize the positron dynamics in each system, we calculated the radiation profile generated from the annihilation, their diffusion profiles and the most probable distances for excitation and ionization. (authors)

Delisting efforts for mixed radioactive and chemically hazardous waste at the Oak Ridge Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Goodpasture, S.T.

1987-01-01

Presently, there are four hazardous wastes at the Oak Ridge Gaseous Diffusion Plant that are candidates for the delisting from the Resource Conservation and Recovery Act (RCRA) hazardous waste regulations. These candidates are the sludges from K-1407-B and C ponds, Central Neutralization Facility sludges, mixed sludges from Y-12 and the ash generated by the RCRA/Toxic Substances Control Act (TSCA) Incinerator. All of these hazardous wastes contain radioactive constituents as well as hazardous constituents. The delisting will be based upon the nonradioactive constituents. Whether the delisting petition is granted or not, the wastes will be handled according to the Department of Energy guidelines for radioactive wastes. The presentation discusses the methodologies for delisting these wastes and the rationale behind the processes

Reassessment of liquefaction potential and estimation of earthquake- induced settlements at Paducah Gaseous Diffusion Plant, Paducah, Kentucky. Final report

International Nuclear Information System (INIS)

Sykora, D.W.; Yule, D.E.

1996-04-01

This report documents a reassessment of liquefaction potential and estimation of earthquake-induced settlements for the U.S. Department of Energy (DOE), Paducah Gaseous Diffusion Plant (PGDP), located southwest of Paducah, KY. The U.S. Army Engineer Waterways Experiment Station (WES) was authorized to conduct this study from FY91 to FY94 by the DOE, Oak Ridge Operations (ORO), Oak Ridge, TN, through Inter- Agency Agreement (IAG) No. DE-AI05-91OR21971. The study was conducted under the Gaseous Diffusion Plant Safety Analysis Report (GDP SAR) Program

Technical and economic aspects of new gaseous diffusion uranium enrichment capacity

International Nuclear Information System (INIS)

Langley, R.A. Jr.; O'Donnell, A.J.

1977-01-01

Work is well advanced on design and construction of the next major increment of U.S. uranium enrichment capacity. The plant will use the gaseous diffusion process to provide the required capacity and reliability at a competitive enrichment services cost. Gaseous diffusion technology is the base against which other processes are compared in order to assess their commercial viability. While it has generally been described as a mature technology with limited future development potential, work on design of the new U.S. plant has resulted in major improvement in plant design with corresponding decreases in plant capacity and operating costs. The paper describes major technological advances incorporated into the new plant design and their impact on enrichment costs. These include the effects of: - advanced barrier technology; - tandem compressor drive systems; - optimization of number of equipment sizes; - single level plant design; - development of rapid power level change capability; - electrical system simplification; - plant arrangement and layout. Resulting capital costs and projected enrichment costs are summarized. Enrichment costs are placed in the context of total nuclear fuel cycle costs. Trade-offs between uranium feed material quantities and enrichment plant tails assays are described, and optimization of this aspect of the nuclear fuel cycle is discussed. The effect on enrichment plant characteristics is described. Flexibility and capability of the new U.S. enrichment plant to meet these changing optimization conditions are described

The Blend Down Monitoring System Demonstration at the Padijcah Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Benton, J.; Close, D.; Johnson, W. Jr.; Kerr, P.; March-Leuba, J.; Mastal, E.; Moss, C.; Powell, D.; Sumner, J.; Uckan, T.; Vines, R.; Wright, P.D.

1999-01-01

Agreements between the governments of the US and the Russian Federation for the US purchase of low enriched uranium (LEU) derived from highly enriched uranium (HEU) from dismantled Russian nuclear weapons calls for the establishment of transparency measures to provide confidence that nuclear nonproliferation goals are being met. To meet these transparency goals, the agreements call for the installation of nonintrusive US instruments to monitor the down blending of HEU to LEU. The Blend Down Monitoring System (BDMS) has been jointly developed by the Los Alamos National Laboratory (LANL) and the Oak Ridge National Laboratory (ORNL) to continuously monitor 235 U enrichments and mass flow rates at Russian blending facilities. Prior to its installation in Russian facilities, the BDMS was installed and operated in a UF 6 flow loop in the Paducah Gaseous Diffusion Plant simulating flow and enrichment conditions expected in a typical down-blending facility. A Russian delegation to the US witnessed the equipment demonstration in June, 1998. To conduct the demonstration in the Paducah Gaseous Diffusion Plant (PGDP), the BDMS was required to meet stringent Nuclear Regulatory Commission licensing, safety and operational requirements. The Paducah demonstration was an important milestone in achieving the operational certification for the BDMS use in Russian facilities

Investigation of gas-phase decontamination of internally radioactively contaminated gaseous diffusion process equipment and piping

International Nuclear Information System (INIS)

Bundy, R.D.; Munday, E.B.

1991-01-01

Construction of the gaseous diffusion plants (GDPs) was begun during World War 2 to produce enriched uranium for defense purposes. These plants, which utilized UF 6 gas, were used primarily for this purpose through 1964. From 1959 through 1968, production shifted primarily to uranium enrichment to supply the nuclear power industry. Additional UF 6 -handling facilities were built in feed and fuel-processing plants associated with the uranium enrichment process. Two of the five process buildings at Oak ridge were shut down in 1964. Uranium enrichment activities at Oak Ridge were discontinued altogether in 1985. In 1987, the Department of Energy (DOE) decided to proceed with a permanent shutdown of the Oak Ridge Gaseous Diffusion Plant (ORGDP). DOE intends to begin decommissioning and decontamination (D ampersand D) of ORGDP early in the next century. The remaining two GDPs are expected to be shut down during the next 10 to 40 years and will also require D ampersand D, as will the other UF 6 -handling facilities. This paper presents an investigation of gas- phase decontamination of internally radioactively contaminated gaseous diffusion process equipment and piping using powerful fluorinating reagents that convert nonvolatile uranium compounds to volatile UF 6 . These reagents include ClF 3 , F 2 , and other compounds. The scope of D ampersand D at the GDPs, previous work of gas-phase decontamination, four concepts for using gas-phase decontamination, plans for further study of gas-phase decontamination, and the current status of this work are discussed. 13 refs., 15 figs

Buildup of 236U in the gaseous diffusion plant product

International Nuclear Information System (INIS)

Ford, J.S.

1975-01-01

A generalized projection of the average annual 236 U concentration that can be expected in future enriched uranium product from the US-ERDA gaseous diffusion plants when reprocessed fuels become available for cascade feeding is given. It is concluded that the buildup of 236 U is not an ever-increasing function, but approaches a limiting value. Projected concentrations result in only slight separative work losses and present no operational problem to ERDA in supplying light water reactor requirements. The use of recycle uranium from power reactor spent fuels will result in significant savings in natural uranium feed

78 FR 66779 - United States Enrichment Corporation, Paducah Gaseous Diffusion Plant, Including On-Site Leased...

Science.gov (United States)

2013-11-06

... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-82,862] United States Enrichment..., applicable to workers of United States Enrichment Corporation, Paducah Gaseous Diffusion Plant, including on... were engaged in the production of low enrichment uranium. The company reports that workers leased from...

Determination of 1-octanol-air partition coefficient using gaseous diffusion in the air boundary layer.

Science.gov (United States)

Ha, Yeonjeong; Kwon, Jung-Hwan

2010-04-15

Exact determination of the partition coefficient between 1-octanol and air (K(OA)) is very important because it is a key descriptor for describing the thermodynamic partitioning between the air and organic phases. In spite of its importance, the number and quality of experimental K(OA) values for hydrophobic organic chemicals are limited because of experimental difficulties. Thus, to measure K(OA) values, a high-throughput method was developed that used liquid-phase extraction with 1-octanol drop at the tip of a microsyringe needle. The concentration in the headspace surrounding the 1 muL octanol drop was equilibrated with liquid octanol containing polycyclic aromatic hydrocarbons (PAHs). The change in concentrations of PAHs in the octanol drop was measured to obtain mass transfer rate constants, and these rate constants were then converted into K(OA) values using a film diffusion model. Thirteen polycyclic aromatic hydrocarbons with log K(OA) between 5 and 12 were chosen for the proof of the principle. Experimental determination of log K(OA) was accomplished in 30 h for PAHs with their log K(OA) less than 11. The measured log K(OA) values were very close to those obtained by various experimental and estimation methods in the literature, suggesting that this new method can provide a fast and easy determination of log K(OA) values for many chemicals of environmental interests. In addition, the applicability of the method can be extended to determine Henry's law constant for compounds with low vapor pressure and to estimate gaseous transfer rate of semivolatile compounds for environmental fate modeling.

Dispersion of UO2F2 aerosol and HF vapor in the operating floor during winter ventilation at the Paducah Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Kim, S.H.; Chen, N.C.J.; Taleyarkhan, R.P.; Keith, K.D.; Schmidt, R.W.; Carter, J.C.

1996-01-01

The gaseous diffusion process is currently employed at two plants in the US: the Paducah Gaseous Diffusion Plant and the Portsmouth Gaseous Diffusion Plant. As part of a facility-wide safety evaluation, a postulated design basis accident involving large line-rupture induced releases of uranium hexafluoride (UF 6 ) into the process building of a gaseous diffusion plant (GDP) is evaluated. When UF 6 is released into the atmosphere, it undergoes an exothermic chemical reaction with moisture (H 2 O) in the air to form vaporized hydrogen fluoride (HF) and aerosolized uranyl fluoride (UO 2 F 2 ). These reactants disperse in the process building and transport through the building ventilation system. The ventilation system draws outside air into the process building, distributes it evenly throughout the building, and discharges it to the atmosphere at an elevated temperature. Since air is recirculated from the cell floor area to the operating floor, issues concerning in-building worker safety and evacuation need to be addressed. Therefore, the objective of this study is to evaluate the transport of HF vapor and UO 2 F 2 aerosols throughout the operating floor area following B-line break accident in the cell floor area

Separation of a multicomponent mixture by gaseous diffusion: modelization of the enrichment in a capillary - application to a pilot cascade

International Nuclear Information System (INIS)

Doneddu, F.

1982-01-01

Starting from the modelization of gaseous flow in a porous medium (flow in a capillary), we generalize the law of enrichment in an infinite cylindrical capillary, established for an isotropic linear mixture, to a multicomponent mixture. A generalization is given of the notion of separation yields and characteristic pressure classically used for separations of isotropic linear mixtures. We present formulas for diagonalizing the diffusion operator, modelization of a multistage, gaseous diffusion cascade and comparison with the experimental results of a drain cascade (N 2 -SF 6 -UF 6 mixture). [fr

Oak Ridge Reservation Volume 2. Records relating to cesium at the K-25 Plant: A guide to record series of the Department of Energy and its contractors

International Nuclear Information System (INIS)

1995-01-01

The purpose of this guide is to describe the documents and record series at the K-25 plant that pertain to the handling of waste containing cesium-137 produced as a result of processes to enrich uranium and separate plutonium at the Department of Energy's (DOE) Oak Ridge National Laboratory (ORNL) and Oak Ride Gaseous Diffusion Plant (ORGDP, called K-25) in Oak Ridge, Tennessee. History Associates Incorporated (HAI) prepared this guide as part of DOE's Epidemiologic Records Inventory Project, the purpose of which is to verify and conduct inventories of epidemiologic and health-related records at various DOE and DOE contractor sites. This introduction briefly describes the Epidemiologic Records Inventory Project and HAI's role in it. Specific attention is given to the history of the DOE-Oak Ridge Reservation, the history and development of the K-25 plant, the creation and handling of cesium-contaminated waste, and environmental monitoring efforts at ORNL and K-25 from the late 1940s to the present. This introduction also presents the methodology used to identify the documents and series pertaining to cesium, a discussion of the inventory of these documents, information concerning access to the site and the records, and a description of the arrangement of the chapters

Oak Ridge Reservation Volume 2. Records relating to cesium at the K-25 Plant: A guide to record series of the Department of Energy and its contractors

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-02-21

The purpose of this guide is to describe the documents and record series at the K-25 plant that pertain to the handling of waste containing cesium-137 produced as a result of processes to enrich uranium and separate plutonium at the Department of Energy`s (DOE) Oak Ridge National Laboratory (ORNL) and Oak Ride Gaseous Diffusion Plant (ORGDP, called K-25) in Oak Ridge, Tennessee. History Associates Incorporated (HAI) prepared this guide as part of DOE`s Epidemiologic Records Inventory Project, the purpose of which is to verify and conduct inventories of epidemiologic and health-related records at various DOE and DOE contractor sites. This introduction briefly describes the Epidemiologic Records Inventory Project and HAI`s role in it. Specific attention is given to the history of the DOE-Oak Ridge Reservation, the history and development of the K-25 plant, the creation and handling of cesium-contaminated waste, and environmental monitoring efforts at ORNL and K-25 from the late 1940s to the present. This introduction also presents the methodology used to identify the documents and series pertaining to cesium, a discussion of the inventory of these documents, information concerning access to the site and the records, and a description of the arrangement of the chapters.

Natural phenomena hazards evaluation of equipment and piping of Gaseous Diffusion Plant Uranium Enrichment Facility

International Nuclear Information System (INIS)

Singhal, M.K.; Kincaid, J.H.; Hammond, C.R.; Stockdale, B.I.; Walls, J.C.

1995-01-01

In support of the Gaseous Diffusion Plant Safety Analysis Report Upgrade program (GDP SARUP), a natural phenomena hazards evaluation was performed for the main process equipment and piping in the uranium enrichment buildings at Paducah and Portsmouth gaseous diffusion plants. In order to reduce the cost of rigorous analyses, the evaluation methodology utilized a graded approach based on an experience data base collected by SQUG/EPRI that contains information on the performance of industrial equipment and piping during past earthquakes. This method consisted of a screening walkthrough of the facility in combination with the use of engineering judgment and simple calculations. By using these screenings combined with evaluations that contain decreasing conservatism, reductions in the time and cost of the analyses were significant. A team of experienced seismic engineers who were trained in the use of the DOE SQUG/EPRI Walkdown Screening Material was essential to the success of this natural phenomena hazards evaluation

Natural phenomena hazards evaluation of equipment and piping of Gaseous Diffusion Plant Uranium Enrichment Facility

Energy Technology Data Exchange (ETDEWEB)

Singhal, M.K.; Kincaid, J.H.; Hammond, C.R.; Stockdale, B.I.; Walls, J.C. [Oak Ridge National Lab., TN (United States). Technical Programs and Services; Brock, W.R.; Denton, D.R. [Lockheed Martin Energy Systems, Inc., Oak Ridge, TN (United States)

1995-12-31

In support of the Gaseous Diffusion Plant Safety Analysis Report Upgrade program (GDP SARUP), a natural phenomena hazards evaluation was performed for the main process equipment and piping in the uranium enrichment buildings at Paducah and Portsmouth gaseous diffusion plants. In order to reduce the cost of rigorous analyses, the evaluation methodology utilized a graded approach based on an experience data base collected by SQUG/EPRI that contains information on the performance of industrial equipment and piping during past earthquakes. This method consisted of a screening walkthrough of the facility in combination with the use of engineering judgment and simple calculations. By using these screenings combined with evaluations that contain decreasing conservatism, reductions in the time and cost of the analyses were significant. A team of experienced seismic engineers who were trained in the use of the DOE SQUG/EPRI Walkdown Screening Material was essential to the success of this natural phenomena hazards evaluation.

The new local control systems for operating gaseous diffusion plant units at Pierrelatte

International Nuclear Information System (INIS)

Delacroix, C.

1990-01-01

The development of a local control network for operating gaseous diffusion plant units is presented. The objective of the control system up date was to replace all the information network hardware. The new generation HP1000 calculators and a network architecture were chosen. The validation tests performed in laboratory and in situ, and the management policies towards the personnel during the technical changes are summarized [fr

TC-99 Decontaminant from heat treated gaseous diffusion membrane -Phase I, Part B

Energy Technology Data Exchange (ETDEWEB)

Oji, L. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Restivo, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Duignan, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Wilmarth, B. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2017-11-01

Uranium gaseous diffusion cascades represent a significant environmental challenge to dismantle, containerize and dispose as low-level radioactive waste. Baseline technologies rely on manual manipulations involving direct access to technetium-contaminated piping and materials. There is a potential to utilize novel decontamination technologies to remove the technetium and allow for on-site disposal of the very large uranium converters. Technetium entered these gaseous diffusion cascades as a hexafluoride complex in the same fashion as uranium. Technetium, as the isotope Tc-99, is an impurity that follows uranium in the first cycle of the Plutonium and Uranium Extraction (PUREX) process. The technetium speciation or exact form in the gaseous diffusion cascades is not well defined. Several forms of Tc-99 compounds, mostly the fluorinated technetium compounds with varying degrees of volatility have been speculated by the scientific community to be present in these cascades. Therefore, there may be a possibility of using thermal or leaching desorption, which is independent of the technetium oxidation states, to perform an insitu removal of the technetium as a volatile species and trap the radionuclide on sorbent traps which could be disposed as low-level waste. Based on the positive results of the first part of this work1 the use of steam as a thermal decontamination agent was further explored with a second piece of used barrier material from a different location. This new series of tests included exposing more of the material surface to the flow of high temperature steam through the change in the reactor design, subjecting it to alternating periods of stream and vacuum, as well as determining if a lower temperature steam, i.e., 121°C (250°F) would be effective, too. Along with these methods, one other simpler method involving the leaching of the Tc-99 contaminated barrier material with a 1.0 M aqueous solution of ammonium carbonate, with and without sonication, was

Paducah Gaseous Diffusion Plant environmental report for 1989

Energy Technology Data Exchange (ETDEWEB)

Turner, J.W. (ed.) (Martin Marietta Energy Systems, Inc., Oak Ridge, TN (USA))

1990-10-01

This two-part environmental report is published annually. It reflects the results of a comprehensive, year-round program to monitor the impact of operations at Paducah Gaseous Diffusion Plant (PGDP) on the area's groundwater and surface waters, soil, air quality, vegetation, and wildlife. In addition, an assessment of the effect of PGDP effluents on the resident human population is made. PGDP's overall goal for environmental management is to protect the environment and PGDP's neighbors and to maintain full compliance with all current regulations. The current environmental strategy is to identify any deficiencies and to develop a system to resolve them. The long-range goal of environmental management is to minimize the source of pollutants, to reduce the formation of waste, and to minimize hazardous waste by substitution of materials. 36 refs.

Radioactive diffusion gaseous probe technique for study adsorbent structure inhomogeneity

International Nuclear Information System (INIS)

Zyuzin, A.Yu.; Korobkov, V.I.; Bekman, I.N.

1990-01-01

One of the versions of the method of diffusion gaseous probe - method of longitudinal shear in combination with autoradiography (ARG) - was used for characterising sorbents and catalysts, which are considered to be promising for reprocessing of sulfur-containing natural gases. Hydrogen sulfide, labelled with 35 S was used as diffusion radioactive probe. Zeolite granules of 4A type and granulated adsorbents on the basis of CR and AM aluminium oxides, which are industrial catalysts of Clauss reaction developed at SNEA company, were used as objects under investigation. It is shown that technique for fabrication of 4A zeolite granules leads to asymmetrical pore distribution over the granule diameter. Technique for AM granule fabrication leads to occuRrence of local inhomogeneities of the structure in the form of narrow coaxial rings with decreased or increased local adsorption ability. Granules of adsorbent of CR type are characterized by rather homogeneous structure. It is recommended to use the mentioned method for industrial adsorbent diagnosis

Non-destructive measurement methods for large scale gaseous diffusion process equipment

International Nuclear Information System (INIS)

Mayer, R.L.; Hagenauer, R.C.; McGinnis, B.R.

1994-01-01

Two measurement methods have been developed to measure non-destructively uranium hold-up in gaseous diffusion plants. These methods include passive neutron and passive γ ray measurements. An additional method, high resolution γ ray spectroscopy, provides supplementary information about additional γ ray emitting isotopes, γ ray correction factors, 235 U/ 234 U ratios and 235 U enrichment. Many of these methods can be used as a general purpose measurement technique for large containers of uranium. Measurement applications for these methods include uranium hold-up, waste measurements, criticality safety and nuclear accountability

Re-enrichment of depleted uranium by passage through a gaseous diffusion installation; Reenrichissement de l'uranium appauvri par passage dans une installation de diffusion gazeuse

Energy Technology Data Exchange (ETDEWEB)

Lagrange, P; Billous, O [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1958-07-01

The reader will find in this paper an economic study of the re-utilization of depleted uranium from nuclear reactors, whether its content be above or under natural proportions. Re-utilization is possible either through bringing the depleted product up to its initial content of {sup 235}U by mixture with a richer concentrate, or else by passing it through a gaseous diffusion plant. The economic area of such re-utilization depends on a number of considerations. We give a general study of it, with reference to some typical gaseous diffusion facilities. (author)Fren. [French] Ce rapport examine au point de vue economique la reutilisation de l'uranium appauvri provenant des reacteurs nucleaires, qu'il soit indifferemment en dessus ou en dessous de la teneur naturelle. Cette reutilisation peut se faire soit en ramenant le produit a sa teneur initiale en isotope 235 par un melange convenable avec un concentre plus riche, soit en le faisant passer dans une usine de Diffusion Gazeuse. La zone de rentabilite de cette reutilisation depend de diverses conditions economiques. Elle est etudiee ci-dessous d'une maniere generale, puis en se referant a des installations-type de diffusion gazeuse. (auteur)

Physics of Fresh Produce Safety: Role of Diffusion and Tissue Reaction in Sanitization of Leafy Green Vegetables with Liquid and Gaseous Ozone-Based Sanitizers.

Science.gov (United States)

Shynkaryk, Mykola V; Pyatkovskyy, Taras; Mohamed, Hussein M; Yousef, Ahmed E; Sastry, Sudhir K

2015-12-01

Produce safety has received much recent attention, with the emphasis being largely on discovery of how microbes invade produce. However, the sanitization operation deserves more attention than it has received. The ability of a sanitizer to reach the site of pathogens is a fundamental prerequisite for efficacy. This work addresses the transport processes of ozone (gaseous and liquid) sanitizer for decontamination of leafy greens. The liquid sanitizer was ineffective against Escherichia coli K-12 in situations where air bubbles may be trapped within cavities. A model was developed for diffusion of sanitizer into the interior of produce. The reaction rate of ozone with the surface of a lettuce leaf was determined experimentally and was used in a numerical simulation to evaluate ozone concentrations within the produce and to determine the time required to reach different locations. For aqueous ozone, the penetration depth was limited to several millimeters by ozone self-decomposition due to the significant time required for diffusion. In contrast, gaseous sanitizer was able to reach a depth of 100 mm in several minutes without depletion in the absence of reaction with surfaces. However, when the ozone gas reacted with the produce surface, gas concentration was significantly affected. Simulation data were validated experimentally by measuring ozone concentrations at the bottom of a cylinder made of lettuce leaf. The microbiological test confirmed the relationship between ozone transport, its self-decomposition, reaction with surrounding materials, and the degree of inactivation of E. coli K-12. Our study shows that decontamination of fresh produce, through direct contact with the sanitizer, is more feasible with gaseous than with aqueous sanitizers. Therefore, sanitization during a high-speed washing process is effective only for decontaminating the wash water.

Diffusion in the Muscovite 40K Decay System (Invited)

Science.gov (United States)

Harrison, T. M.

2010-12-01

The considerable potential of muscovite for thermochronological applications is beginning to be fully exploited following the belated publication of Ar kinetic data. Muscovite’s high potassium content, low solubility for excess 40Ar*, and ubiquitous presence in regionally metamorphosed terranes make it an important phase for 40Ar/39Ar thermochronometry, particularly in light of recognition that both age spectra and vacuum-step-heating-derived 39Ar Arrhenius plots reflect Ar release via the same volume diffusion mechanism. Thus instead of assuming a nominal closure temperature to estimate a single T-t datum, continuous and accurate thermal histories can be inferred in a similar fashion to that well-documented for K-feldspar using the multi-diffusion domain (MDD) model. The Arrhenius parameters for Ar diffusion in muscovite (E=64 kcal/mol, Do=4 cm2/s) correspond to an effective intragrain closure temperature range of ~500 to 300oC for ca. 100 μm grains cooling at ~10oC/Ma at 5 kbar. However, even greater exploitation of the 40K decay system remains possible as only one of every ten 40K atoms decay to 40Ar. The other 90% decay to 40Ca giving the 40K-40Ca branch, in principle, greater sensitivity for dating high K/Ca minerals such as muscovite. The advent of the ‘double-plus’ SIMS 40K++-40Ca++ dating method, which permits analysis of Ca isotopes at an MRP of ~4k rather than the ~25k required for full separation of 40K+ from 40Ca+, opens up the prospect of directly revealing 40K-40Ca closure profiles in muscovite (as opposed to their indirect inference from inversion of 40Ar/39Ar data through the MDD model) at a gain of enhanced precision and accuracy in thermal history reconstruction. We have used SIMS to observe K-Ca age variations in natural muscovites pressed into In. Translating this data into thermal history information, however, requires knowledge of the Arrhenius parameters for Ca tracer diffusion in muscovite. We are undertaking hydrothermal piston

Analysis and evalaution in the production process and equipment area of the low-cost solar array project. [including modifying gaseous diffusion and using ion implantation

Science.gov (United States)

Goldman, H.; Wolf, M.

1979-01-01

The manufacturing methods for photovoltaic solar energy utilization are assessed. Economic and technical data on the current front junction formation processes of gaseous diffusion and ion implantation are presented. Future proposals, including modifying gaseous diffusion and using ion implantation, to decrease the cost of junction formation are studied. Technology developments in current processes and an economic evaluation of the processes are included.

Acoustic pressure amplitude thresholds for rectified diffusion in gaseous microbubbles in biological tissue

DEFF Research Database (Denmark)

Lewin, Peter A.; Jensen, Leif Bjørnø

1981-01-01

One of the mechanisms often suggested for the biological action of ultrasonic beams irradiating human tissues is concerned with the presence in the tissues of minute gaseous bubbles which may, under the influence of the ultrasonic field be stimulated to grow to a size at which resonance or collap...... of calculations for typical (transient) exposure conditions from pulse-echo equipment are presented, indicating that rectified diffusion and stable cavitation are improbable phenomena in these circumstances....

Real Time Demonstration Project XRF Performance Evaluation Report for Paducah Gaseous Diffusion Plant AOC 492

Energy Technology Data Exchange (ETDEWEB)

Johnson, Robert L [Argonne National Laboratory

2008-04-03

This activity was undertaken to demonstrate the applicability of market-available XRF instruments to quantify metal concentrations relative to background and risk-based action and no action levels in Paducah Gaseous Diffusion Plant (PGDP) soils. As such, the analysis below demonstrates the capabilities of the instruments relative to soil characterization applications at the PGDP.

Environmental Survey preliminary report, Oak Ridge Gaseous Diffusion Plant, Oak Ridge, Tennessee

International Nuclear Information System (INIS)

1989-02-01

This report presents the preliminary findings from the first phase of the Environmental Survey of the US Department of Energy's (DOE) Oak Ridge Gaseous Diffusion Plant (ORGDP) conducted March 14 through 25, 1988. The Survey is being conducted by an interdisciplinary team of environmental specialists, led and managed by the Office of Environment, Safety and Health's Office of Environmental Audit. Individual team components are being supplied by a private contractor. The objective of the Survey is to identify environmental risk associated with ORGDP. The Survey covers all environmental media and all areas of environmental regulation. It is being performed in accordance with the DOE Environmental Survey Manual. This phase of the Survey involves the review of existing site environmental data, observations of the operations carried on at ORGDP, and interviews with site personnel. The Survey team developed a Sampling and Analysis Plan to assist in further assessing certain of the environmental problems identified during is on-site activities. The Sampling and Analysis Plan will be executed by Idaho National Engineering Laboratory (INEL). When completed, the results will be incorporated into the ORGDP Survey findings for in inclusion into the Environmental Survey Summary Report. 120 refs., 41 figs., 74 tabs

Cleanup operations at the Oak Ridge Gaseous Diffusion Plant contaminated metal scrapyard

International Nuclear Information System (INIS)

Williams, L.C.

1987-01-01

Cleanup operations at the contaminated metal storage yard located at the Oak Ridge, Tennessee, Gaseous Diffusion Plant have been completed. The storage yard, in existence since the early 1970s, contained an estimated 35,000 tons of mixed-type metals spread over an area of roughly 30 acres. The overall cleanup program required removing the metal from the storage yard, sorting by specific metal types, and size reduction of specific types for future processing. This paper explains the methods and procedures used to accomplish this task

Separation of tritium from gaseous and aqueous effluent systems

International Nuclear Information System (INIS)

Kobisk, E.H.

1977-01-01

Three processes are discussed for separating tritium from gaseous and aqueous effluent systems: separation in the gas phase using Pd-25 wt percent Ag alloy diffusion membranes; electrolytic separation in the aqueous phase using ''bipolar'' electrodes; and the countercurrent exchange of tritium-containing hydrogen gas with water on catalytic surfaces combined with separation by direct electrolysis

The Final Demise Of East Tennessee Technology Park Building K-33

International Nuclear Information System (INIS)

King, David A.

2011-01-01

Building K-33 was constructed in 1954 as the final section of the five-stage uranium enrichment cascade at the Oak Ridge Gaseous Diffusion Plant (ORGDP). The two original building (K-25 and K-27) were used to produce weapons grade highly enriched uranium (HEU). Building K-29, K-31, and K-33 were added to produce low enriched uranium (LEU) for nuclear power plant fuel. During ORGDP operations K-33 produced a peak enrichment of 2.5%. Thousands of tons of reactor tails fed into gaseous diffusion plants in the 1950s and early 1960s introducing some fission products and transuranics. Building K-33 was a two-story, 25-meters (82-feet) tall structure with approximately 30 hectare (64 acres) of floor space. The Operations (first) Floor contained offices, change houses, feed vaporization rooms, and auxiliary equipment to support enrichment operations. The Cell (second) Floor contained the enrichment process equipment and was divided into eight process units (designated K-902-1 through K-902-8). Each unit contained ten cells, and each cell contained eight process stages (diffusers) for a total of 640 enrichment stages. 1985: LEU buildings were taken off-line after the anticipated demand for uranium enrichment failed to materialize. 1987: LEU buildings were placed in permanent shutdown. Process equipment were maintained in a shutdown state. 1997: DOE signed an Action Memorandum for equipment removal and decontamination of Buildings K-29, K-31, K-33; BNFL awarded contract to reindustrialize the buildings under the Three Buildings D and D and Recycle Project. 2002: Equipment removal complete and effort shifts to vacuuming, chemical cleaning, scabbling, etc. 2005: Decontamination efforts in K-33 cease. Building left with significant 99 Tc contamination on metal structures and PCB contamination in concrete. Uranium, transuranics, and fission products also present on building shell. 2009: DOE targets Building K-33 for demolition. 2010: ORAU contracted to characterize Building K-33

Environmental Restoration Site-Specific Plan for the Paducah Gaseous Diffusion Plant, FY 93

International Nuclear Information System (INIS)

1993-01-01

This report provides an overview of the major Environmental Restoration (ER) concerns at Paducah Gaseous Diffusion Plant (PGDP). The identified solid waste management units at PGDP are listed. In the Department of Energy (DOE) Five Year Plan development process, one or more waste management units are addressed in a series of activity data sheets (ADSs) which identify planned scope, schedule, and cost objectives that are representative of the current state of planned technical development for individual or multiple sites

Portsmouth Gaseous Diffusion Plant expansion, Piketon, Ohio. Volume 1. Draft environmental statement

Energy Technology Data Exchange (ETDEWEB)

1976-06-01

Subject to authorizing legislation and funding, ERDA will proceed with steps for additional uranium enrichment capacity at the Portsmouth Gaseous Diffusion Plant near Piketon, Ohio. This environmental statement was prepared by ERDA to cover this action. The statement was prepared in accordance with the National Environmental Policy Act of 1969, and ERDA's implementing regulations, 10 CFR Chapter III, Part 711. The statement describes the reasonably foreseeable environmental, social, economic and technological costs and benefits of the construction and operation of the expanded enrichment plant and its reasonably available alternatives and their anticipated effects.

Portsmouth Gaseous Diffusion Plant expansion, Piketon, Ohio. Volume 1. Draft environmental statement

International Nuclear Information System (INIS)

1976-06-01

Subject to authorizing legislation and funding, ERDA will proceed with steps for additional uranium enrichment capacity at the Portsmouth Gaseous Diffusion Plant near Piketon, Ohio. This environmental statement was prepared by ERDA to cover this action. The statement was prepared in accordance with the National Environmental Policy Act of 1969, and ERDA's implementing regulations, 10 CFR Chapter III, Part 711. The statement describes the reasonably foreseeable environmental, social, economic and technological costs and benefits of the construction and operation of the expanded enrichment plant and its reasonably available alternatives and their anticipated effects

General productivity code: productivity optimization of gaseous diffusion cascades. The programmer's guide

International Nuclear Information System (INIS)

Tunstall, J.N.

1975-05-01

The General Productivity Code is a FORTRAN IV computer program for the IBM System 360. With its model of the productivity of gaseous diffusion cascades, the program is used to determine optimum cascade performance based on specified operating conditions and to aid in the calculation of optimum operating conditions for a complex of diffusion cascades. This documentation of the program is directed primarily to programmers who will be responsible for updating the code as requested by the users. It is also intended to be an aid in training new Productivity Code users and to serve as a general reference manual. Elements of the mathematical model, the input data requirements, the definitions of the various tasks (Instructions) that can be performed, and a detailed description of most FORTRAN variables and program subroutines are presented. A sample problem is also included. (auth)

Gaseous diffusion plant transition from DOE to external regulation

International Nuclear Information System (INIS)

Dann, R.K.; Crites, T.R.; Rahm-Crites, L.K.

1997-01-01

After many years of operation as government-owned/contractor-operated facilities, large portions of the gaseous diffusion plants (GDPs) at Portsmouth, Ohio, and Paducah, Kentucky, were leased to the United States Enrichment Corporation (USEC). These facilities are now certified by the U.S. Nuclear Regulatory Commission (NRC) and subject to oversight by the Occupational Safety and Health Administration (OSHA). The transition from DOE to NRC regulation was more difficult than expected. The original commitment was to achieve NRC certification in October 1995; however, considerably more time was required and transition-related costs escalated. The Oak Ridge Operations Office originally estimated the cost of transition at $60 million; $240 million has been spent to date. The DOE's experience in transitioning the GDPs to USEC operation with NRC oversight provides valuable lessons (both positive and negative) that could be applied to future transitions

Project plan for the background soils project for the Paducah Gaseous Diffusion Plant, Paducah, Kentucky

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-09-01

The Background Soils Project for the Paducah Gaseous Diffusion Plant (BSPP) will determine the background concentration levels of selected naturally occurring metals, other inorganics, and radionuclides in soils from uncontaminated areas in proximity to the Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky. The data will be used for comparison with characterization and compliance data for soils, with significant differences being indicative of contamination. All data collected as part of this project will be in addition to other background databases established for the PGDP. The BSPP will address the variability of surface and near-surface concentration levels with respect to (1) soil taxonomical types (series) and (2) soil sampling depths within a specific soil profile. The BSPP will also address the variability of concentration levels in deeper geologic formations by collecting samples of geologic materials. The BSPP will establish a database, with recommendations on how to use the data for contaminated site assessment, and provide data to estimate the potential human and health and ecological risk associated with background level concentrations of potentially hazardous constituents. BSPP data will be used or applied as follows.

Project plan for the background soils project for the Paducah Gaseous Diffusion Plant, Paducah, Kentucky

International Nuclear Information System (INIS)

1995-09-01

The Background Soils Project for the Paducah Gaseous Diffusion Plant (BSPP) will determine the background concentration levels of selected naturally occurring metals, other inorganics, and radionuclides in soils from uncontaminated areas in proximity to the Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky. The data will be used for comparison with characterization and compliance data for soils, with significant differences being indicative of contamination. All data collected as part of this project will be in addition to other background databases established for the PGDP. The BSPP will address the variability of surface and near-surface concentration levels with respect to (1) soil taxonomical types (series) and (2) soil sampling depths within a specific soil profile. The BSPP will also address the variability of concentration levels in deeper geologic formations by collecting samples of geologic materials. The BSPP will establish a database, with recommendations on how to use the data for contaminated site assessment, and provide data to estimate the potential human and health and ecological risk associated with background level concentrations of potentially hazardous constituents. BSPP data will be used or applied as follows

Diffusion coefficients of D2 and HT in the medium of gaseous protium and in crystals of NaX zeolite

International Nuclear Information System (INIS)

Polevoj, A.S.

1993-01-01

Coefficients of HT diffusion (absent in literature) in gaseous protium medium and in crystals of the NaX zeolite compared with similar values of these coefficients for deuterium are determined on the basis of analysis of experimental data on effect NaX zeolite grain size and of H 2 -HT gaseous mixture consumption in the sorption column at separation of hydrogen atoms on the value of transfer unit. 15 refs., 1 fig., 1 tab

Environmental Survey preliminary report, Oak Ridge Gaseous Diffusion Plant, Oak Ridge, Tennessee

Energy Technology Data Exchange (ETDEWEB)

1989-02-01

This report presents the preliminary findings from the first phase of the Environmental Survey of the US Department of Energy's (DOE) Oak Ridge Gaseous Diffusion Plant (ORGDP) conducted March 14 through 25, 1988. The Survey is being conducted by an interdisciplinary team of environmental specialists, led and managed by the Office of Environment, Safety and Health's Office of Environmental Audit. Individual team components are being supplied by a private contractor. The objective of the Survey is to identify environmental risk associated with ORGDP. The Survey covers all environmental media and all areas of environmental regulation. It is being performed in accordance with the DOE Environmental Survey Manual. This phase of the Survey involves the review of existing site environmental data, observations of the operations carried on at ORGDP, and interviews with site personnel. The Survey team developed a Sampling and Analysis Plan to assist in further assessing certain of the environmental problems identified during is on-site activities. The Sampling and Analysis Plan will be executed by Idaho National Engineering Laboratory (INEL). When completed, the results will be incorporated into the ORGDP Survey findings for in inclusion into the Environmental Survey Summary Report. 120 refs., 41 figs., 74 tabs.

Characterization of process holdup material at the Portsmouth Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Boyd, D.E.; Miller, R.R.

1986-01-01

The cascade material balance area at the Portsmouth Gaseous Diffusion Plant is characterized by continuous, large, in-process inventories of gaseous uranium hexafluoride (UF 6 ) and very large inputs and outputs of UF 6 over a complete range of 235 U enrichments. Monthly inventories are conducted to quantify the in-place material, but the inventory techniques are blind to material not in the gas phase. Material is removed from the gas phase by any one of four mechanisms: (1) freeze-outs which are the solidification of UF 6 , (2) inleakage of wet air which produces solid uranium oxyfluorides, (3) consumption of uranium through UF 6 reaction with internal metal surfaces, and (4) adsorption of UF 6 on internal surfaces. This presentation describes efforts to better characterize and, where possible, to eliminate or reduce the effects of these mechanisms on material accountability. Freeze-outs and wet air deposits occur under absormal operating conditions, and techniques are available to prevent, detect and reverse them. Consumption and adsorption occur under normal operating conditions and are more complex to manage, however, computer models have been developed to quantify monthly the net effects due to consumption and adsorption. These models have shown that consumption and adsorption effects on inventory differences are significant

Nuclear criticality safety controls for uranium deposits during D and D at the Oak Ridge Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Haire, M.J.; Jordan, W.C.; Jollay, L.J. III; Dahl, T.L.

1997-01-01

The US Department of Energy (DOE) Deputy Assistant Secretary of Energy for Environmental Management has issued a challenge to complete DOE environmental cleanup within a decade. The response for Oak Ridge facilities is in accordance with the DOE ten-year plan which calls for completion of > 95% of environmental management work by the year 2006. This will result in a 99% risk reduction and in a significant savings in base line costs in waste management (legacy waste); remedial action (groundwater, soil, etc.); and decontamination and decommissioning (D and D). It is assumed that there will be long-term institutional control of cascade equipment, i.e., there will be no walk away from sites, and that there will be firm radioactivity release limits by 1999 for recycle metals. An integral part of these plants is the removal of uranium deposits which pose nuclear criticality safety concerns in the shut down of the Oak Ridge Gaseous Diffusion Plant. DOE has initiated the Nuclear Criticality Stabilization Program to improve nuclear criticality safety by removing the larger uranium deposits from unfavorable geometry equipment. Nondestructive assay (NDA) measurements have identified the location of these deposits. The objective of the K-25 Site Nuclear Criticality Stabilization Program is to remove and place uranium deposits into safe geometry storage containers to meet the double contingency principle. Each step of the removal process results in safer conditions where multiple controls are present. Upon completion of the Program, nuclear criticality risks will be greatly reduced

Introduction to the nuclear criticality safety evaluation of facility X-705, Portsmouth Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Sheaffer, M.K.; Keeton, S.C.

1993-01-01

This report is the first in a series of documents that will evaluate nuclear criticality safety in the Decontamination and Recovery Facility, X-705, Portsmouth Gaseous Diffusion Plant. It provides an overview of the facility, categorizes its functions for future analysis, reviews existing NCS documentation, and explains the follow-on effort planned for X-705. A detailed breakdown of systems, subsystems, and operational areas is presented and cross-referenced to existing NCS documentation

Portsmouth Gaseous Diffusion Plant annual site environmental report for 1993

Energy Technology Data Exchange (ETDEWEB)

Horak, C.M. [ed.

1994-11-01

This calendar year (CY) 1993 annual report on environmental monitoring of the US Department of Energy`s (DOE`s) Portsmouth Gaseous Diffusion Plant (Portsmouth) and its environs consists of three separate documents: a summary pamphlet for the general public; a more detail discussion and of compliance status, data, and environmental impacts (this document); and a volume of detailed data that is available on request. The objectives of this report are to report compliance status during 1993; provide information about the plant site and plant operations; report 1993 monitoring data for the installation and its environs that may have been affected by operations on the plant site; document information on input and assumptions used in calculations; provide trend analyses (where appropriate) to indicate increases and decreases in environmental impact, and provide general information on quality assurance for the environmental monitoring program.

Portsmouth Gaseous Diffusion Plant annual site environmental report for 1993

International Nuclear Information System (INIS)

Horak, C.M.

1994-11-01

This calendar year (CY) 1993 annual report on environmental monitoring of the US Department of Energy's (DOE's) Portsmouth Gaseous Diffusion Plant (Portsmouth) and its environs consists of three separate documents: a summary pamphlet for the general public; a more detail discussion and of compliance status, data, and environmental impacts (this document); and a volume of detailed data that is available on request. The objectives of this report are to report compliance status during 1993; provide information about the plant site and plant operations; report 1993 monitoring data for the installation and its environs that may have been affected by operations on the plant site; document information on input and assumptions used in calculations; provide trend analyses (where appropriate) to indicate increases and decreases in environmental impact, and provide general information on quality assurance for the environmental monitoring program

Fundamental laws of separation by the gaseous diffusion process; Lois de separation elementaires en diffusion gazeuse

Energy Technology Data Exchange (ETDEWEB)

Bouligand, G M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-07-01

Using the Knudsen's law for the flow of each component of a gaseous mixture through a porous membrane, we derive the overall separation laws and the separation power for one stage of diffusion: Various types of stages differing by the geometrical configuration and the flow nature are considered. For the sake of simplicity physical phenomena causing a loss of separation efficiency are neglected. Computation show the advantages of counter-current type stage with one entering and two leaving flows. A more refined theory of separation can be derived with the same basis of this work. (author) [French] A partir de la loi de Knudsen exprimant les debits elementaires des constituants d'un melange gazeux a travers une membrane poreuse on determine les lois et la puissance de separation de differents modeles de diffuseurs definie par leurs configurations et la nature des ecoulements gazeux. Four simplifier il n'a pas ete tenu compte des divers phenomenes physiques inherents a la diffusion et qui reduisent generalement le facteur de separation. Ces calculs font prevoir les avantages des diffuseurs du type contrecourant a trois ouvertures et peuvent servir de guide dans une theorie plus complete de la separation. (auteur)

Bioavailability study for the Paducah Gaseous Diffusion Plant

Energy Technology Data Exchange (ETDEWEB)

Phipps, T.L.; Kszos, L.A.

1996-08-01

The overall purpose of this plan is to assess the bioavailability of metals in the continuous and intermittent outfalls. The results may be used to determine alternative metal limits that more appropriately measure the portion of metal present necessary for toxicity to aquatic life. These limits must remain protective of in-stream aquatic life; thus, the highest concentration of metal in the water will be determined concurrently with an assessment of acute or chronic toxicity on laboratory tests. Using the method developed by the Kentucky Division of Water (KDOW), biomonitoring results and chemical data will be used to recommend alternative metal limits for the outfalls of concern. The data will be used to meet the objectives of the study: (1) evaluate the toxicity of continuous outfalls and intermittent outfalls at Paducah Gaseous Diffusion Plant; (2) determine the mean ratio of dissolved to Total Recoverable metal for Cd, Cr, Cu, Pb, Ni, and Zn in the continuous and intermittent outfalls; (3) determine whether the concentration of total recoverable metal discharged causes toxicity to fathead minnows and /or Ceriodaphnia; and (4) determine alternative metal limits for each metal of concern (Cd, Cr, Cu, Pb, Ni, and Zn).

Raffinate treatment at the Portsmouth Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Acox, T.A.

1983-01-01

Raffinate solutions, which contain uranium, technetium, nitrates, and lesser amounts of heavy metals, are produced in the decontamination and uranium recovery operations at the Portsmouth Gaseous Diffusion Plant. These solutions are presently being placed in temporary storage until three treatment facilities are constructed which will produce an environmentally acceptable effluent from the raffinate. These facilities are: (1) The Heavy Metals Precipitation Facility; (2) The Technetium Ion Exchange Facility; and (3) The Biodenitrification Pilot Plant. When the facilities are completed, the raffinate will be treated in 500 gallon batches. The first treatment is the heavy metals precipitation by caustic addition and filtering. The effluent proceeds to the ion exchange columns where the technetium is removed by adsorption onto a strongly basic, anion exchange resin which has been converted to the hydroxyl form. Following ion exchange, the solution is transported to the biodenitrification pilot plant. The biodenitrification column is a fluidized-bed using bacteria-laden coal particles as the denitrifying media. The resulting effluent should meet the limits established by the US EPA for all metals and nitrate. Technetium will be 98+% removed and the uranium concentration will be less than one milligram per liter. 13 references

Nuclear criticality safety evaluation of Spray Booth Operations in X-705, Portsmouth Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Sheaffer, M.K.; Keeton, S.C.

1993-01-01

This report evaluates nuclear criticality safety for Spray Booth Operations in the Decontamination and Recovery Facility, X-705, at the Portsmouth Gaseous Diffusion Plant. A general description of current procedures and related hardware/equipment is presented. Control parameters relevant to nuclear criticality safety are explained, and a consolidated listing of administrative controls and safety systems is developed. Based on compliance with DOE Orders and MMES practices, the overall operation is evaluated, and recommendations for enhanced safety are suggested

Size Effect on Transport Properties of Gaseous Argon: A Molecular Dynamics Simulation Study

International Nuclear Information System (INIS)

Lee, Songhi

2014-01-01

We have carried out a series of equilibrium molecular dynamics (EMD) simulations of gaseous argon at 273.15 K and 1.00 atm for the calculation of transport properties as a function of the number of argon molecules (N). While the diffusion coefficients (D) of gaseous argon approach to the experimental measure with increasing N, the viscosities (η) and thermal conductivities (λ) obtained for N = 432 are unreliable due to the high fluctuation of the time correlation functions and those for N = 1728 are rather acceptable. Increasing further to N = 6912 has improved the MD results a little closer to the experimental measures for η and λ. Both the EMD results for η and λ for N = 6912 underestimate the experimental measures and it is not expected that the more increasing N makes the closer results to the experimental measures. One possible explanation for the large disagreement between MD results and the experimental measures for η and λ may be due to the use of LJ parameters which were used for liquid argon. In a recent study, we have examined the Green-Kubo formula for the calculation of transport properties (diffusion coefficient, viscosity, and thermal conductivity) of noble gases (He, Ne, Ar, Kr, and Xe) by carrying out a series of equilibrium molecular dynamics (EMD) simulations for the system of N=1728 at 273.15 K and 1.00 atm.1 While the diffusion coefficients (D) of noble gases were obtained through the original Green-Kubo formula, the viscosities (η) and thermal conductivities (λ) were obtained by utilizing the revised Green-Kubo formulas. The structural and dynamic properties of gaseous argon are completely different from those of liquid argon at 94.4 K and 1.374 g/cm 3 . The results for transport properties (D, η, and λ) at 273.15 K and 1.00 atm obtained from our EMD simulations are in general agreement with the experimental data and superior to the rigorous results of the kinetic theory

Measurement of the Portsmouth Gaseous Diffusion Plant criticality accident alarm

International Nuclear Information System (INIS)

Tayloe, R.W. Jr.; McGinnis, B.

1990-01-01

Measurements of the Portsmouth Gaseous Diffusion Plant's nuclear criticality accident radiation alarm signal response time, sound wave frequency, and sound volume levels were made to demonstrate compliance with ANSI/ANS-8.3-1986. A steady-state alarm signal is produced within one-half second of obtaining a two-out-of-three detector trip. The fundamental alarm sound wave frequency is 440 hertz. The sound volume levels are greater than 10 decibels above background and ranged from 100 to 125 A-weighted decibels. The requirements of the standard were met; however the recommended maximum sound volume level of 115 dBA was exceeded. Emergency procedures require immediate evacuation upon initiation of a facility's radiation alarm. Comparison with standards for allowable time of exposure at different noise levels indicate that the elevated noise level at this location does not represent an occupational injury hazard. 8 refs., 5 figs

Analog simulation of concentration transients in a gaseous diffusion plant (1961); Etude sur simulateur des regimes transitoires des concentrations dans une installation de diffusion gazeuse (1961)

Energy Technology Data Exchange (ETDEWEB)

Delarousse, P; Trouve, C; Jacques, R [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1962-07-01

A finite difference system is used to describe concentration transients in a gaseous diffusion plant for uranium isotope separation. The equipment used in this study is described and examples are given to illustrate the problems which have been solved with it. (authors) [French] Le comportement transitoire d'une cascade de diffusion gazeuse est represente de facon approchee par un systeme differentiel aux differences. On decrit le materiel analogique original qui a permis de simuler ce systeme. Une serie d'exemples illustre les differents problemes qui ont ete resolus au moyen de cet appareil. (auteurs)

PGDP [Paducah Gaseous Diffusion Plant]-UF6 handling, sampling, analysis and associated QC/QA and safety related procedures

International Nuclear Information System (INIS)

Harris, R.L.

1987-01-01

This document is a compilation of Paducah Gaseous Diffusion Plant procedures on UF 6 handling, sampling, and analysis, along with associated QC/QA and safety related procedures. It was assembled for transmission by the US Department of Energy to the Korean Advanced Energy Institute as a part of the US-Korea technical exchange program

Direct estimation of diffuse gaseous emissions from coal fires: current methods and future directions

Science.gov (United States)

Engle, Mark A.; Olea, Ricardo A.; O'Keefe, Jennifer M. K.; Hower, James C.; Geboy, Nicholas J.

2013-01-01

Coal fires occur in nature spontaneously, contribute to increases in greenhouse gases, and emit atmospheric toxicants. Increasing interest in quantifying coal fire emissions has resulted in the adaptation and development of specialized approaches and adoption of numerical modeling techniques. Overview of these methods for direct estimation of diffuse gas emissions from coal fires is presented in this paper. Here we take advantage of stochastic Gaussian simulation to interpolate CO2 fluxes measured using a dynamic closed chamber at the Ruth Mullins coal fire in Perry County, Kentucky. This approach allows for preparing a map of diffuse gas emissions, one of the two primary ways that gases emanate from coal fires, and establishing the reliability of the study both locally and for the entire fire. Future research directions include continuous and automated sampling to improve quantification of gaseous coal fire emissions.

French Regulatory Framework for the Recycling/Reuse of Nuclear Waste and the Dismantling of George Besse Gaseous Diffusion Plant

Energy Technology Data Exchange (ETDEWEB)

Themines, R., E-mail: robert.themines@areva.com [AREVA (France)

2011-07-15

The regulatory framework in France governing the management of materials containing low levels of radionuclides is described. The plans for the management of the materials arising from the dismantling of the Georges Besse Gaseous Diffusion Plant are described as an example of the application of the regulations. (author)

IAEA verification experiment at the Portsmouth Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Gordon, D.M.; Subudhi, M.; Calvert, O.L.; Bonner, T.N.; Cherry, R.C.; Whiting, N.E.

1998-01-01

In April 1996, the United States (US) added the Portsmouth Gaseous Diffusion Plant to the list of facilities eligible for the application of International Atomic Energy Agency (IAEA) safeguards. At that time, the US proposed that the IAEA carry out a Verification Experiment at the plant with respect to the downblending of about 13 metric tons of highly enriched uranium (HEU) in the form of UF 6 . This material is part of the 226 metric tons of fissile material that President Clinton has declared to be excess to US national-security needs and which will be permanently withdrawn from the US nuclear stockpile. In September 1997, the IAEA agreed to carry out this experiment, and during the first three weeks of December 1997, the IAEA verified the design information concerning the downblending process. The plant has been subject to short-notice random inspections since December 17, 1997. This paper provides an overview of the Verification Experiment, the monitoring technologies used in the verification approach, and some of the experience gained to date

Development of NF3 Deposit Removal Technology for the Portsmouth Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Scheele, R.D.; McNamara, B.K.; Rapko, B.M.; Edwards, M.K.; Kozelisky, A.E.; Daniel, R.C.; McSweeney, T.I.; Maharas, S.J.; Weaver, P.J.; Iwamasa, K.J.; Kefgen, R.B.

2006-01-01

This paper summarizes the Battelle, Stoller, and WASTREN (BSW) team's efforts, to date, in support of the United States Department of Energy's plans to remove uranium and technetium deposits before decommissioning the Portsmouth Gaseous Diffusion Plant. The BSW team investigated nitrogen trifluoride (NF 3 ) as a safer yet effective alternative gaseous treatment to the chlorine trifluoride (ClF 3 )-elemental fluorine (F 2 ) treatment currently used to remove uranium and technetium deposits from the uranium enrichment cascade. Both ClF 3 and F 2 are highly reactive, toxic, and hazardous gases, while NF 3 , although toxic [1], is no more harmful than moth balls [2]. BSW's laboratory thermo-analytical and laboratory-scale prototype studies with NF 3 established that thermal NF 3 can effectively remove likely and potential uranium (UO 2 F 2 and UF 4 ) and technetium deposits (a surrogate deposit material, TcO 2 , and pertechnetates) by conversion to volatile compounds. Our engineering evaluations suggest that NF 3 's effectiveness could be enhanced by combining with a lesser concentration of ClF 3 . BSW's and other's studies indicate compatibility with Portsmouth materials of construction (aluminum, copper, and nickel). (authors)

Fundamental laws of separation by the gaseous diffusion process; Lois de separation elementaires en diffusion gazeuse

Energy Technology Data Exchange (ETDEWEB)

Bouligand, G.M. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1964-07-01

Using the Knudsen's law for the flow of each component of a gaseous mixture through a porous membrane, we derive the overall separation laws and the separation power for one stage of diffusion: Various types of stages differing by the geometrical configuration and the flow nature are considered. For the sake of simplicity physical phenomena causing a loss of separation efficiency are neglected. Computation show the advantages of counter-current type stage with one entering and two leaving flows. A more refined theory of separation can be derived with the same basis of this work. (author) [French] A partir de la loi de Knudsen exprimant les debits elementaires des constituants d'un melange gazeux a travers une membrane poreuse on determine les lois et la puissance de separation de differents modeles de diffuseurs definie par leurs configurations et la nature des ecoulements gazeux. Four simplifier il n'a pas ete tenu compte des divers phenomenes physiques inherents a la diffusion et qui reduisent generalement le facteur de separation. Ces calculs font prevoir les avantages des diffuseurs du type contrecourant a trois ouvertures et peuvent servir de guide dans une theorie plus complete de la separation. (auteur)

Freezer-sublimer for gaseous diffusion plant

International Nuclear Information System (INIS)

Reti, G.R.

1978-01-01

A method and apparatus is disclosed for freezing and subliming uranium hexafluoride (UF 6 ) as part of a gaseous diffusion plant from which a quantity of the UF 6 inventory is intermittently withdrawn and frozen to solidify it. A plurality of upright heat pipes holds a coolant and is arranged in a two compartment vessel, the lower compartment is exposed to UF 6 , the higher one serves for condensing the evaporated coolant by means of cooling water. In one embodiment, each pipe has a quantity of coolant such as freon, hermetically sealded therein. In the other embodiment, each pipe is sealed only at the lower end while the upper end communicates with a common vapor or cooling chamber which contains a water cooled condenser. The cooling water has a sufficiently low temperature to condense the evaporated coolant. The liquid coolant flows gravitationally downward to the lower end portion of the pipe. UF 6 gas is flowed into the tank where it contacts the finned outside surface of the heat pipes. Heat from the gas evaporates the coolant and the gas in turn is solidified on the exterior of the heat pipe sections in the tank. To recover UF 6 gas from the tank, the solidified UF 6 is sublimed by passing compressed UF 6 gas over the frozen UF 6 gas on the pipes or by externally heating the lower ends of the pipes sufficiently to evaporate the coolant therein above the subliming temperature of the UF 6 . The subliming UF 6 gas then condenses the coolant in the vertical heat pipes, so that it can gravitationally flow back to the lower end portions

Innovative Decontamination Technology for Use in Gaseous Diffusion Plant Decommissioning

International Nuclear Information System (INIS)

Peters, M.J.; Norton, C.J.; Fraikor, G.B.; Potter, G.L.; Chang, K.C.

2006-01-01

The results of bench scale tests demonstrated that TechXtract R RadPro TM technology (hereinafter referred to as RadPro R ) can provide 100% coverage of complex mockup gaseous diffusion plant (GDP) equipment and can decontaminate uranium (U) deposits with 98% to 99.99% efficiency. Deployment tests demonstrated RadPro R can be applied as foam, mist/fog, or steam, and fully cover the internal surfaces of complex mockup equipment, including large piping. Decontamination tests demonstrated that two formulations of RadPro R , one with neutron attenuators and one without neutron attenuators, could remove up to 99.99% of uranyl fluoride deposits, one of the most difficult to remove deposits in GDP equipment. These results were supplemented by results from previous tests conducted in 1994 that showed RadPro R could remove >97% of U and Tc-99 contamination from actual GDP components. Operational use of RadPro R at other DOE and commercial facilities also support these data. (authors)

Measurement of the Portsmouth Gaseous Diffusion Plant criticality accident alarm

International Nuclear Information System (INIS)

Tayloe, R.W. Jr.; D'Aquila, D.M.; McGinnis, R.B.

1991-01-01

The nuclear criticality accident radiation alarm system installed at the Portsmouth Gaseous Diffusion Plant was tested extensively at critical facilities located at the Los Alamos National Laboratory. The ability of the neutron scintillator radiation detection units to respond to a minimum accident of concern as defined in Standard ANSI/ANS-83.-1986 was demonstrated. Detector placement and the established trip point are based on shielding calculations performed by the Oak Ridge National Laboratory and criticality specialists at the Portsmouth plant. Based on these experiments and calculations, a detector trip point of 5 mrad/h in air is used. Any credible criticality accident is expected to produce neutron radiation fields >5 mrad/h in air at one or more radiation alarm locations. Each radiation alarm location has a cluster of three detectors that employs a two-out-of-three alarm logic. Earlier work focused on testing the alarm logic latching circuitry. This work was directed toward measurements involving the actual audible alarm signal delivered

An aerial radiological survey of the Paducah Gaseous Diffusion Plant and surrounding area, Paducah, Kentucky

International Nuclear Information System (INIS)

1992-11-01

An aerial radiological survey of the Paducah Gaseous Diffusion Plant (PGDP) and surrounding area in Paducah, Kentucky, was conducted during May 15--25, 1990. The purpose of the survey was to measure and document the terrestrial radiological environment at the PGDP and surrounding area for use in effective environmental management and emergency response planning. The aerial survey was flown at an altitude of 61 meters (200 feet) along a series of parallel lines 107 meters (350 feet) apart. The survey encompassed an area of 62 square kilometers (24 square miles), bordered on the north by the Ohio River. The results of the aerial survey are reported as inferred exposure rates at 1 meter above ground level in the form of a gamma radiation contour map. Typical background exposure rates were found to vary from 5 to 12 microroentgens per hour (μR/h). Protactinium-234m, a radioisotope indicative of uranium-238, was detected at several facilities at the PGDR. In support of the aerial survey, ground-based exposure rate and soil sample measurements were obtained at several sites within the survey perimeter. The results of the aerial and ground-based measurements were found to agree within ±15%

Partnering efforts at the Paducah Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Warren, C.B.

1995-01-01

Before individuals or agencies can effectively work together to solve common problems, they must first agree on exactly what those problems are and establish common goals and methods that will lead to mutually acceptable solutions. Then, they must make a conscientious effort to form a cohesive team that focuses on the established goals and deemphasize traditional roles, which may in some instances be considered adversarial. This kind of teamwork/partnering process can be more difficult, though not impossible, to achieve in cases where there are traditional (real or imagined) adversarial relationships between the parties, i.e. regulator vs. regulated. The US Department of Energy Site Office (DOE) at Paducah, Kentucky, the Kentucky Department of Environmental Protection (KDEP) and the US Environmental Protection Agency, Region IV (EPA) have made t strides toward teamwork and partnering at DOE's Paducah Gaseous Diffusion Plant. They have accomplished this in a number of ways, which will be discussed in greater detail but first and foremost, the agencies agreed up front that they had mutual goals and interests. These goals are to protect public health and the environment in a cost-effective and timely manner, taking care to make the wisest use of public resources (tax dollars); to evaluate and minimize risks, and to achieve ''Win-Win'' for all parties concerned

Portsmouth Gaseous Diffusion Plant environmental report for 1989

Energy Technology Data Exchange (ETDEWEB)

Turner, J.W. (ed.) (Martin Marietta Energy Systems, Inc., Oak Ridge, TN (USA))

1990-10-01

This calendar year 1989 annual report on environmental surveillance of the US Department of Energy's (DOE) Portsmouth Gaseous Diffusion Plant (PORTS) and its environs consists of two parts: the Summary, Discussion, and Conclusions (Part 1) and the Data Presentation (Part 2). The objectives of this report are the following: report 1989 monitoring data for the installation and its environs that may have been affected by operations on the plant site, provide reasonably detailed information about the plant site and plant operations, provide detailed information on input and assumptions used in all calculations, provide trend analyses (where appropriate) to indicate increases and decreases in environmental impact, and provide general information on plant quality assurance. Routine monitoring and sampling for radiation, radioactive materials, and chemical substances on and off the DOE site are used to document compliance with appropriate standards, to identify trends, to provide information for the public, and to contribute to general environmental knowledge. The surveillance program assists in fulfilling the DOE policy of protecting the public, employees, and environment from harm that could be caused by its activities and reducing negative environmental impacts to the greatest degree practicable. Environmental-monitoring information complements data on specific releases, trends, and summaries. 26 refs.

DIFFUSIVE EXCHANGE OF GASEOUS POLYCYCLIC AROMATIC HYDROCARBONS AND POLYCHLORINATED BIPHENYLS ACROSS THE AIR-WATER INTERFACE OF THE CHESAPEAKE BAY. (R825245)

Science.gov (United States)

Dissolved and gas-phase concentrations of nine polycyclic aromatic hydrocarbons and 46 polychlorinated biphenyl congeners were measured at eight sites on the Chesapeake Bay at four different times of the year to estimate net diffusive air-water gas exchange rates. Gaseous PAHs ar...

irradiation growth in annealed Zr2.5wt%Nb at 3530K

International Nuclear Information System (INIS)

Rogerson, A.; Murgatroyd, R.A.

1978-10-01

Zr 2.5wt%Nb growth specimens have been irradiated at 353 0 K to a fast neutron dose of approximately 4.0 x 10 25 n/m 2 . Specimens were taken from the longitudinal and transverse directions of a nominally annealed, seam-welded tube and irradiated in both the stress relieved and fully annealed conditions. Growth in these specimens is characterised by large positive and negative strains in the longitudinal and transverse directions respectively, with dimensional changes in weld material exhibiting intermediate growth behaviour. The results are compared with growth data on both annealed and cold worked Zircaloy-2 at 353 0 K and discussed in terms of the effect of texture, grain size, and cold work on irradiation growth. It is concluded that the continuation of growth to high doses in annealed Zr-2.5wt%Nb at 353 0 K results from interstitial induced dislocation climb with vacancies diffusing to grain boundaries. (author)

K-25 Structural Separation and Demolition

International Nuclear Information System (INIS)

Cater, Frank

2008-01-01

The K-25 building is a former gaseous diffusion plant, built in 1944-1945 as part of the United States Manhattan Project. The structure was the largest structure under one roof, surpassed only by the Pentagon. Together the three wings represent about 17.8 hectare (44 acres) under roof and are generally about 18.3 meters (60 ft.) high on the outside face and approximately 12.2 meters (40 ft.) high on the inside face. The entire structure was built in the shape of a 'U', with a lateral distance of approximately one mile. It was constructed in individual building units with each unit connected using expansion joint-type connection. A single unit is approximately 24.4 meters (80 ft.) across and 122 meters (400 ft.) deep. The northern structure is connected to the eastern and western structures at the upper level floors. The four-level, U-shaped building is a steel-frame structure with corrugated cement-asbestos siding. The cell level is an elevated concrete structure supported by reinforced concrete columns located in the basement, or vault area. The vault area can be accessed at grade level from the outside perimeter. Inside the courtyard, the grade level has been raised to provide entry to the second or cell floor level. An engineering evaluation of the structure was performed to determine the condition of the structure and possibility of unplanned collapse of any portion of the structure. The evaluation included physical inspections, calculations for wind, pre-demolition loads, and evaluation of failure modes. The results of the evaluation have provided guidance for the demolition plan and the development of criteria for protection of personnel performing pre-demolition activities. Challenges include degradation of the structure that necessitated repair, dealing with changes in the code revisions from both the American Concrete Institute (ACI) and the American Institute of Steel Construction (AISC), access to areas of the structure that were not necessarily designed

An in situ survey of the Paducah Gaseous Diffusion Plant and surrounding area

International Nuclear Information System (INIS)

Hoover, R.A.

1994-02-01

An in situ survey of the area surrounding the Paducah Gaseous Diffusion Plant was conducted between May 17 and 24, 1990. The survey consisted of in situ measurements and of ground sampling. A High Purity Germanium detector was used for the in situ measurements. The ground samples were taken to the, laboratory at EG ampersand G Energy Measurements, Inc., in Santa Barbara, California, for a radionuclide assay on a laboratory system. Results of the in situ measurements found evidence of naturally occurring radioisotopes, cesium-137 from international fallout, and some evidence of anomalous uranium-238. The soil sampling results show only the presence of naturally occurring radioisotopes, cesium-137, and also anomalous uranium-238

Air sampling program at the Portsmouth Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Hulett, S.H.

1975-01-01

An extensive air sampling program has been developed at the Portsmouth Gaseous Diffusion Plant for monitoring the concentrations of radioactive aerosols present in the atmosphere on plantsite as well as in the environs. The program is designed to minimize exposures of employees and the environment to airborne radioactive particulates. Five different air sampling systems, utilizing either filtration or impaction, are employed for measuring airborne alpha and beta-gamma activity produced from 235 U and 234 Th, respectively. Two of the systems have particle selection capabilities: a personal sampler with a 10-mm nylon cyclone eliminates most particles larger than about 10 microns in diameter; and an Annular Kinetic Impactor collects particulates greater than 0.4 microns in diameter which have a density greater than 12-15 gm/cm 3 . A Hi-Volume Air Sampler and an Eberline Model AIM-3 Scintillation Air Monitor are used in collecting short-term samples for assessing compliance with ''ceiling'' standards or peak concentration limits. A film-sort aperture IBM card system is utilized for continuous 8-hour samples. This sampling program has proven to be both practical and effective for assuring accurate monitoring of the airborne activity associated with plant operations

Validation of KENO V.a for the Portsmouth Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Felsher, H.D.; Fentiman, A.W.; Tayloe, R.W.; D'Aquila, D.

1992-01-01

At the Portsmouth Gaseous Diffusion Plant, KENO V.a is used to make criticality calculations for complex configurations and a wide range of 235 U enrichments. It is essential that the calculated critical conditions either accurately reflect the true critical state or that the bias from the true critical conditions are well known. Accordingly, a study has been initiated to validate KENO V.a over the ranges of parameters expected to be used when modeling equipment and processes at Portsmouth. Preliminary results of that study are reported in this paper. The ultimate goal of this study is to identify a set of data from existing critical experiments that will exercise all KENO V.a parameters commonly used by Portsmouth's criticality safety personnel. A second goal is to identify a relatively small subset of those experiments that may be run frequently to ensure that KENO V.a provides consistent results

Seismically-induced soil amplification at the DOE Paducah Gaseous Diffusion Plant site

International Nuclear Information System (INIS)

Sykora, D.W.; Haynes, M.E.

1991-01-01

A site-specific earthquake site response (soil amplification) study is being conducted for the Department of Energy (DOE), Paducah Gaseous Diffusion Plant (PGDP). This study is pursuant to an upgraded Final Safety Analysis Report in accordance with requirements specified by DOE. The seismic hazard at PGDP is dominated by the New Madrid Seismic Zone. Site-specific synthetic earthquake records developed by others were applied independently to four soil columns with heights above baserock of about 325 ft. The results for the 1000-year earthquake event indicate that the site period is between 1.0 and 1.5 sec. Incident shear waves are amplified at periods of motion greater than 0.15 sec. The peak free-field horizontal acceleration, occurring at very low periods, is 0.28 g. 13 refs., 13 figs

Seismically-induced soil amplification at the DOE Paducah Gaseous Diffusion Plant Site

International Nuclear Information System (INIS)

Sykora, D.W.; Hynes, M.E.; Brock, W.R.; Hunt, R.J.; Shaffer, K.E.

1991-01-01

A site-specific earthquake site response (soil amplification) study is being conducted for the Department of Energy (DOE), Paducah Gaseous Diffusion Plant (PGDP). This study is pursuant to an upgraded Final Safety Analysis Report in accordance with requirements specified by DOE. The seismic hazard at PGDP is dominated by the New Madrid Seismic Zone. Site-specific synthetic earthquake records developed by others were applied independently to four soil columns with heights above baserock of about 325 ft. The results for the 1000-year earthquake event indicate that the site period is between 1.0 and 1.5 sec. Incident shear waves are strongly amplified at periods of motion greater than 0.3 sec. The peak free-field horizontal acceleration, occurring at very low periods, is 0.28 g

Determination of the separation factor of uranium isotopes by gaseous diffusion; Determination des facteurs de separation des isotopes de l'uranium par diffusion gazeuse

Energy Technology Data Exchange (ETDEWEB)

Bilous, O; Counas, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1958-07-01

A 12-stage pilot separation cascade with a low output has been constructed to measure the separation factor of uranium isotopes by gaseous diffusion. The report describes some of the separation results obtained, and also provides information on the time necessary for equilibrium to be established and on the influence of various perturbations on the pressure profile in the cascade. (author) [French] Une cascade pilote de 12 etages de separation a faible debit a ete construite pour mesurer le facteur de separation des isotopes de l'uranium par diffusion gazeuse. Le rapport decrit certains des resultats de separation obtenus et fournit egalement des donnees sur les temps de mise en equilibre et l'influence de diverses perturbations sur le profil des pressions dans la cascade. (auteur)

Potential Hazards Relating to Pyrolysis of c-C4F8O, n-C4F10 and c-C4F8 in selected gaseous diffusion plant operations

International Nuclear Information System (INIS)

Trowbridge, L.D.

2000-01-01

As part of a program intended to replace the present evaporative coolant at the gaseous diffusion plants (GDPs) with a non-ozone-depleting alternate, a series of investigations of the suitability of candidate substitutes is under way. This report summarizes studies directed at estimating the chemical and thermal stability of three candidate coolants, c-C 4 F 8 O, n-C 4 F 10 and c-C 4 4F 8 , in a few specific environments to be found in gaseous diffusion plant operations

Method for estimate the economic characteristics of an uranium enrichment plant by gaseous diffusion

International Nuclear Information System (INIS)

Berault, J.C.

1975-01-01

To estimate the economic characteristics of an uranium enrichment plant by gaseous diffusion is to determine the prospective price of the separative work unit to which leads the concerned technology, and to collect the data allowing to ascertain that this price remains in the area of development of the prices forecasted by the other projects. The prospective price estimated by the promoter is the synthesis of the components of the go decision and which are a potential market and a comprehensive industrially proven plant design, including the basic economic and technical data of the project. Procedures for estimating these components and their synthesis, exclusive of financing problems are reviewed [fr

Environmental site description for a Uranium Atomic Vapor Laser Isotope Separation (U-AVLIS) production plant at the Portsmouth Gaseous Diffusion Plant site

International Nuclear Information System (INIS)

Marmer, G.J.; Dunn, C.P.; Filley, T.H.; Moeller, K.L.; Pfingston, J.M.; Policastro, A.J.; Cleland, J.H.

1991-09-01

Uranium enrichment in the United States has utilized a diffusion process to preferentially enrich the U-235 isotope in the uranium product. In the 1970s, the US Department of Energy (DOE) began investigating more efficient and cost-effective enrichment technologies. In January 1990, the Secretary of Energy approved a plan for the demonstration and deployment of the Uranium Atomic Vapor Laser isotope Separation (U-AVLIS) technology with the near-term goal to provide the necessary information to make a deployment decision by November 1992. Initial facility operation is anticipated for 1999. A programmatic document for use in screening DOE sites to locate a U-AVLIS production plant was developed and implemented in two parts. The first part consisted of a series of screening analyses, based on exclusionary and other criteria, that identified a reasonable number of candidate sites. The final evaluation, which included sensitivity studies, identified the Oak Ridge Gaseous Diffusion Plant (ORGDP) site, the Paducah Gaseous Diffusion Plant (PGDP) site, and the Portsmouth Gaseous Diffusion Plant (PORTS) site as having significant advantages over the other sites considered. This environmental site description (ESD) provides a detailed description of the PORTS site and vicinity suitable for use in an environmental impact statement (EIS). This report is based on existing literature, data collected at the site, and information collected by Argonne National Laboratory (ANL) staff during site visits. The organization of the ESD is as follows. Topics addressed in Sec. 2 include a general site description and the disciplines of geology, water resources, biotic resources, air resources, noise, cultural resources, land use. Socioeconomics, and waste management. Identification of any additional data that would be required for an EIS is presented in Sec. 3

Environmental site description for a Uranium Atomic Vapor Laser Isotope Separation (U-AVLIS) production plant at the Portsmouth Gaseous Diffusion Plant site

Energy Technology Data Exchange (ETDEWEB)

Marmer, G.J.; Dunn, C.P.; Filley, T.H.; Moeller, K.L.; Pfingston, J.M.; Policastro, A.J.; Cleland, J.H.

1991-09-01

Uranium enrichment in the United States has utilized a diffusion process to preferentially enrich the U-235 isotope in the uranium product. In the 1970s, the US Department of Energy (DOE) began investigating more efficient and cost-effective enrichment technologies. In January 1990, the Secretary of Energy approved a plan for the demonstration and deployment of the Uranium Atomic Vapor Laser isotope Separation (U-AVLIS) technology with the near-term goal to provide the necessary information to make a deployment decision by November 1992. Initial facility operation is anticipated for 1999. A programmatic document for use in screening DOE sites to locate a U-AVLIS production plant was developed and implemented in two parts. The first part consisted of a series of screening analyses, based on exclusionary and other criteria, that identified a reasonable number of candidate sites. The final evaluation, which included sensitivity studies, identified the Oak Ridge Gaseous Diffusion Plant (ORGDP) site, the Paducah Gaseous Diffusion Plant (PGDP) site, and the Portsmouth Gaseous Diffusion Plant (PORTS) site as having significant advantages over the other sites considered. This environmental site description (ESD) provides a detailed description of the PORTS site and vicinity suitable for use in an environmental impact statement (EIS). This report is based on existing literature, data collected at the site, and information collected by Argonne National Laboratory (ANL) staff during site visits. The organization of the ESD is as follows. Topics addressed in Sec. 2 include a general site description and the disciplines of geology, water resources, biotic resources, air resources, noise, cultural resources, land use. Socioeconomics, and waste management. Identification of any additional data that would be required for an EIS is presented in Sec. 3.

K25/K27 Characterization for Demonstrating Criticality Incredibility K-25 / K-27 D and D Project

International Nuclear Information System (INIS)

Haghighi, Mahmoud H.; Howe, Kathleen E.; Chandler, John R.

2008-01-01

The K-25 and K-27 Buildings are currently undergoing decontamination and decommissioning (D and D) as part of a non-time critical removal action. When the enrichment process was shut-down, the process gas equipment and piping was purged to remove UF 6 , but the process gas system was not generally chemically treated to remove solid holdup. Generally, chemical treatment was completed it was not very effective in removing the larger deposits. Because of this, uranium deposits continue to reside throughout the process gas system. There is the potential for unreacted UF 6 to be present, as well. A key part of this project is to locate the remaining significant uranium deposits and manage them appropriately. Since some process gas components in the K-25 and K-27 Buildings contain enriched uranium holdup, it is important to ensure nuclear criticality safety during demolition or subsequent loading and transport of waste. Therefore, a major task in preparation for demolition is to demonstrate that 'criticality is incredible (CI)' in each building area. The U.S. Department of Energy (DOE) and Bechtel Jacobs Company LLC (BJC) are in agreement that proper and thorough characterization of fissile holdup material in the K-25 and K-27 process gas components is a key element in achieving and demonstrating that criticality is incredible, as well as in management of demolition wastes and collection of holdup material. While the classic project scheduling wisdom may indicate that performing all of the data quality objectives (DQO) and planning before the field work starts, the size of the K-25 / K-27 D and D Project combined with the evolving decommissioning plans and re-plans have indicated that a fresh look at what further characterization data are needed to meet the current project requirements. Performing a DQO in the middle of the project allowed a much greater degree of accuracy of the real project data needs than was possible even 22 months ago. The outcome of the DQO work

Paducah Gaseous Diffusion Plant Annual Site Environmental Report summary for 1993

International Nuclear Information System (INIS)

1994-11-01

This report contains summaries of the environmental programs at Paducah Gaseous Diffusion Plant, environmental monitoring and the results, and the impact of operations on the environment and the public for 1993. The environmental monitoring program at Paducah includes effluent monitoring and environmental surveillance. Effluent monitoring is measurement of releases as they occur. Contaminants are released through either airborne emissions or liquids discharged from the plant. These releases occur as part of normal site operations, such as cooling water discharged from the uranium enrichment cascade operations or airborne releases from ventilation systems. In the event of system failure, this monitoring provides timely warning so that corrective action can be taken before releases reach an unsafe level. Environmental surveillance tracks the dispersion of materials into the environment after they have been released. This involves the collection of samples from various media, such as water, soil, vegetation, and food crops, and the analysis of these samples for certain radionuclides, chemicals, and metals

Portsmouth Gaseous Diffusion Plant Annual Site Environmental Report summary for 1993

International Nuclear Information System (INIS)

1994-11-01

This report contains summaries of the environmental programs at Paducah Gaseous Diffusion Plant, environmental monitoring and the results, and the impact of operations on the environment and the public for 1993. The environmental monitoring program at Paducah includes effluent monitoring and environmental surveillance. Effluent monitoring is measurement of releases as they occur. Contaminants are released through either airborne emissions or liquids discharged from the plant. These releases occur as part of normal site operations, such as cooling water discharged from the uranium enrichment cascade operations or airborne releases from ventilation systems. In the event of system failure, this monitoring provides timely warning so that corrective action can be taken before releases reach an unsafe level. Environmental surveillance tracks the dispersion of materials into the environment after they have been released. This involves the collection of samples from various media, such as water, soil, vegetation, and food crops, and the analysis of these samples for certain radionuclides, chemicals, and metals

Nuclear criticality safety evaluation of large cylinder cleaning operations in X-705, Portsmouth Gaseous diffusion Plant

International Nuclear Information System (INIS)

Sheaffer, M.K.; Keeton, S.C.; Lutz, H.F.

1995-06-01

This report evaluates nuclear criticality safety for large cylinder cleaning operations in the Decontamination and Recovery Facility, X-705, at the Portsmouth Gaseous Diffusion Plant. A general description of current cleaning procedures and required hardware/equipment is presented, and documentation for large cylinder cleaning operations is identified and described. Control parameters, design features, administrative controls, and safety systems relevant to nuclear criticality are discussed individually, followed by an overall assessment based on the Double Contingency Principle. Recommendations for enhanced safety are suggested, and issues for increased efficiency are presented

Paducah Gaseous Diffusion Plant Northwest Plume interceptor system evaluation

International Nuclear Information System (INIS)

Laase, A.D.; Clausen, J.L.

1998-01-01

The Paducah Gaseous Diffusion Plant (PGDP) recently installed an interceptor system consisting of four wells, evenly divided between two well fields, to contain the Northwest Plume. As stated in the Northwest Plume Record of Decision (ROD), groundwater will be pumped at a rate to reduce further contamination and initiate control of the northwest contaminant plume. The objective of this evaluation was to determine the optimum (minimal) well field pumping rates required for plume hotspot containment. Plume hotspot, as defined in the Northwest Plume ROD and throughout this report, is that portion of the plume with trichloroethene (TCE) concentrations greater than 1,000 microg/L. An existing 3-dimensional groundwater model was modified and used to perform capture zone analyses of the north and south interceptor system well fields. Model results suggest that the plume hotspot is not contained at the system design pumping rate of 100 gallons per minute (gal/min) per well field. Rather, the modeling determined that north and south well field pumping rates of 400 and 150 gal/min, respectively, are necessary for plume hotspot containment. The difference between the design and optimal pumping rates required for containment can be attributed to the discovery of a highly transmissive zone in the vicinity of the two well fields

Exposure to recycled uranium contaminants in gaseous diffusion plants

International Nuclear Information System (INIS)

Anderson, Jeri L.; Yiin, James H.; Tseng, Chih-Yu; Apostoaei, A. Iulian

2017-01-01

As part of an ongoing study of health effects in a pooled cohort of gaseous diffusion plant workers, organ dose from internal exposure to uranium was evaluated. Due to the introduction of recycled uranium into the plants, there was also potential for exposure to radiologically significant levels of "9"9Tc, "2"3"7Np and "2"3"8","2"3"9Pu. In the evaluation of dose response, these radionuclide exposures could confound the effect of internal uranium. Using urine bioassay data for study subjects reported in facility records, intakes and absorbed dose to bone surface, red bone marrow and kidneys were estimated as these organs were associated with a priori outcomes of interest. Additionally, "9"9Tc intakes and doses were calculated using a new systemic model for technetium and compared to intakes and doses calculated using the current model recommended by the International Commission on Radiological Protection. Organ absorbed doses for the transuranics were significant compared to uranium doses; however, "9"9Tc doses calculated using the new systemic model were significant as well. Use of the new model resulted in an increase in "9"9Tc-related absorbed organ dose of a factor of 8 (red bone marrow) to 30 (bone surface). (authors)

Gaseous poison injection device

International Nuclear Information System (INIS)

Kubota, Ryuji; Sugisaki, Toshihiko; Inada, Ikuo.

1983-01-01

Purpose: To rapidly control the chain reaction due to thermal neutrons in a reactor core by using gaseous poisons as back-up means for control rod drives. Constitution: Gaseous poisons having a large neutron absorption cross section are used as back-up means for control rod drives. Upon failure of control rod insertion, the gaseous poisons are injected into the lower portion of the reactor core to control the reactor power. As the gaseous poisons, vapors at a high temperature and a higher pressure than that of the coolants in the reactor core are injected to control the reactor power due to the void effects. Since the gaseous poisons thus employed rapidly reach the reactor core and form gas bubbles therein, the deccelerating effect of the thermal neutrons is decreased to reduce the chain reaction. (Moriyama, K.)

Contamination of liquid oxygen by pressurized gaseous nitrogen

Science.gov (United States)

Zuckerwar, Allan J.; King, Tracy K.; Ngo, Kim Chi

1989-01-01

The penetration of pressurized gaseous nitrogen (GN2) into liquid oxygen (LOX) was investigated experimentally in the 7-inch High Temperature Tunnel, the pilot tunnel for the 8-foot High Temperature Tunnel (8'HTT) at Langley Research Center. A preliminary test using a nuclear monitor revealed the extent of the liquid nitrogen (LN2) build-up at the LOX interface as a function of GN2 pressure. Then an adaptation of the differential flash vaporization technique was used to determine the binary diffusivity of the LOX-LN2 system at a temperature of 90.2 K. The measured value D equals 0.000086 sq cm/s + or - 25 percent together with two prior measurements at lower temperatures revealed an excellent fit to the Arrhenius equation, yielding a pre-exponential factor D sub 0 equals 0.0452 sq cm/s and an activation enthalpy H equals 1.08 kcal/mol. At a pressure of 1700 psi and holding time of 15 min, the penetration of LN2 into LOX (to a 1 percent contamination level) was found to be 0.9 cm, indicating but minimal impact upon 8'HTT operations.

Kinetics of tritium isotope exchange between liquid pyrrole and gaseous hydrogen

International Nuclear Information System (INIS)

Stolarz, A.

1994-01-01

The kinetics of tritium isotope exchange between liquid pyrrole and gaseous hydrogen has been studied over the temperature range of 290-303 K. The reaction was carried out in the presence of platinum black but in spite of that, it appeared to be relatively slow. The kinetics of the exchange reaction studied could be described by the simple McKay equation. The results obtained suggest that diffusion is the rate-determining step. A mechanism of exchange is proposed. (author) 10 refs.; 2 figs.; 1 tab

OCCUPATIONAL EXPOSURE TO TRICHLOROETHYLENE AND CANCER RISK FOR WORKERS AT THE PADUCAH GASEOUS DIFFUSION PLANT

Science.gov (United States)

BAHR, DEBRA E.; ALDRICH, TIMOTHY E.; SEIDU, DAZAR; BRION, GAIL M.; TOLLERUD, DAVID J.; MULDOON, SUSAN; REINHART, NANCY; YOUSEEFAGHA, AHMED; MCKINNEY, PAUL; HUGHES, THERESE; CHAN, CAROLINE; RICE, CAROL; BREWER, DAVID E.; FREYBERG, RONALD W.; MOHLENKAMP, ADRIANE MOSER; HAHN, KRISTEN; HORNUNG, RICHARD; HO, MONA; DASTIDAR, ANIRUDDHA; FREITAS, SAMANTHA; SAMAN, DANIEL; RAVDAL, HEGE; SCUTCHFIELD, DOUGLAS; EGER, KENNETH J.; MINOR, STEVE

2016-01-01

Objective The Paducah Gaseous Diffusion Plant (PGDP) became operational in 1952; it is located in the western part of Kentucky. We conducted a mortality study for adverse health effects that workers may have suffered while working at the plant, including exposures to chemicals. Materials and Methods We studied a cohort of 6820 workers at the PGDP for the period 1953 to 2003; there were a total of 1672 deaths to cohort members. Trichloroethylene (TCE) is a specific concern for this workforce; exposure to TCE occurred primarily in departments that clean the process equipment. The Life Table Analysis System (LTAS) program developed by NIOSH was used to calculate the standardized mortality ratios for the worker cohort and standardized rate ratio relative to exposure to TCE (the U.S. population is the referent for age-adjustment). LTAS calculated a significantly low overall SMR for these workers of 0.76 (95% CI: 0.72–0.79). A further review of three major cancers of interest to Kentucky produced significantly low SMR for trachea, bronchus, lung cancer (0.75, 95% CI: 0.72–0.79) and high SMR for Non-Hodgkin's lymphoma (NHL) (1.49, 95% CI: 1.02–2.10). Results No significant SMR was observed for leukemia and no significant SRRs were observed for any disease. Both the leukemia and lung cancer results were examined and determined to reflect regional mortality patterns. However, the Non-Hodgkin's Lymphoma finding suggests a curious amplification when living cases are included with the mortality experience. Conclusions Further examination is recommended of this recurrent finding from all three U.S. Gaseous Diffusion plants. PMID:21468904

The diffusion and deposition of the gaseous and solid alpha radionuclides/aerosols in air

International Nuclear Information System (INIS)

Danis, A.; Ciubotariu, M.; Oncescu, M.; Mocsy, I.

1999-01-01

The diffusion and deposition of gaseous and solids alpha radionuclides and aerosols in air are processes which implicate low element amounts and therefore their studies require the using of very accurate and sensitive analysis methods. The alpha track method meets these requirements. The used alpha radionuclides were: Rn-222, as gaseous radionuclide and its solid descendants genetically related as solid radionuclides and the descendants attached to different particles from air as alpha aerosols. All these radionuclides were obtained from a calibrated Ra-226 source. The source was included into an air tight device with a well known volume and used after 40 days when the Ra-226 and its alpha descendants were under radioactive equilibrium. The relative amount and activity of each decay product, at any duration, for any initial mass of Ra-226 parent radionuclide, were calculated using a programme for computation of the U-238 radioactive series gamma accumulation, UURASE, adapted for alpha accumulation as ALFAURASE programme. The radon, Rn-222, as well as the solid alpha radionuclides and aerosols were measured using a new alpha monitoring device with or without paper filter for solid radionuclides and aerosols stopping. The track detectors of CR-39 type were incorporated with these monitoring devices. In order to calibrate the CR-39 detectors, a radon intercomparison programme was established with the participation of the SSNTD group from the Institute of Nuclear Research ATOMKI, Debrecen, Hungary, Institute of Public Health, Cluj-Napoca and SSNTD research group from IFIN-HH. We have used for radon calibration a special experimental device and a Ra-226 source. Using an air tight diffusion and deposition device, coupled with the source device, the concentration of radon and solid alpha radionuclides and aerosols were determined using the alpha track method. The alpha monitoring devices were fixed vertically at different distances from the place of radon penetration into

Study of technetium uptake in vegetation in the vicinity of the Portsmouth Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Acox, T.A.

1982-01-01

Technetium-99 was measured in vegetation and soil collected on and near the Portsmouth Gaseous Diffusion Plant to obtain an estimate of the soil-to-vegetation concentration factors. The concentration factors appear to be lognormally distributed with a geometric mean of 3.4 (Bq/kg dry wt. tissue per Bq/kg dry wt. soil) and a geometric standard deviation of 4.7. A dose commitment was calculated using a hypothetical 3.7 x 10 10 Bq Tc-99/year release and the actual CY-1981 concentration release of Tc-99. The radiological significance of Tc-99 in the terrestial food chain is substantially less than previously believed

Group additivity values for enthalpies of formation (298 K), entropies (298 K), and molar heat capacities (300 K < T < 1500 K) of gaseous fluorocarbons

International Nuclear Information System (INIS)

Van Otterloo, Maren K.; Girshick, Steven L.; Roberts, Jeffrey T.

2007-01-01

A group additivity method was developed to estimate standard enthalpies of formation and standard entropies at 298 K of linear radical and closed-shell, gaseous fluorocarbon neutrals containing four or more carbon atoms. The method can also be used to estimate constant pressure molar heat capacities of the same compounds over the temperature range 300 K to 1500 K. Seventeen groups and seven fluorine-fluorine interaction terms were defined from 12 fluorocarbon molecules. Interaction term values from Yamada and Bozzelli [T. Yamada, J.W. Bozzelli, J. Phys. Chem. A 103 (1999) 7373-7379] were utilized. The enthalpy of formation group values were derived from G3MP2 calculations by Bauschlicher and Ricca [C.W. Bauschlicher, A. Ricca, J. Phys. Chem. A 104 (2000) 4581-4585]. Standard entropy and molar heat capacity group values were estimated from ab initio geometry optimization and frequency calculations at the Hartree-Fock level using the 6-31G(d) basis set. Enthalpies of formation for larger fluorocarbons estimated from the group additivity method compare well to enthalpies of formation found in the literature

Martin Marietta Paducah Gaseous Diffusion Plant comprehensive earthquake emergency management program

International Nuclear Information System (INIS)

1990-01-01

Recognizing the value of a proactive, integrated approach to earthquake preparedness planning, Martin Marietta Energy Systems, Inc. initiated a contract in June 1989 with Murray State University, Murray, Kentucky, to develop a comprehensive earthquake management program for their Gaseous Diffusion Plant in Paducah, Kentucky. The overall purpose of the program is to mitigate the loss of life and property in the event of a major destructive earthquake. The program includes four distinct (yet integrated) components: an emergency management plan, with emphasis on the catastrophic earthquake; an Emergency Operations Center Duty Roster Manual; an Integrated Automated Emergency Management Information System (IAEMIS); and a series of five training program modules. The PLAN itself is comprised of four separate volumes: Volume I -- Chapters 1--3; Volume II -- Chapters 4--6, Volume III -- Chapter 7, and Volume IV -- 23 Appendices. The EOC Manual (which includes 15 mutual aid agreements) is designated as Chapter 7 in the PLAN and is a ''stand alone'' document numbered as Volume III. This document, Volume I, provides an introduction, summary and recommendations, and the emergency operations center direction and control

Martin Marietta Paducah Gaseous Diffusion Plant comprehensive earthquake emergency management program

International Nuclear Information System (INIS)

1990-01-01

Recognizing the value of a proactive, integrated approach to earthquake preparedness planning, Martin Marietta Energy Systems, Inc. initiated a contract in June 1989 with Murray State University, Murray, Kentucky, to develop a comprehensive earthquake management program for their Gaseous Diffusion Plant in Paducah, Kentucky (PGDP -- Subcontract No. 19P-JV649V). The overall purpose of the program is to mitigate the loss of life and property in the event of a major destructive earthquake. The program includes four distinct (yet integrated) components: (1) an emergency management plan with emphasis on the catas trophic earthquake; (2) an Emergency Operations Center Duty Roster Manual; (3) an Integrated Automated Emergency Management Information System (IAEMIS); and (4) a series of five training program modules. The PLAN itself is comprised of four separate volumes: Volume I -- Chapters 1--3; Volume II -- Chapters 4--6; Volume III -- Chapter 7; and Volume IV -- 23 Appendices. The EOC Manual (which includes 15 mutual aid agreements) is designated as Chapter 7 in the PLAN and is this document numbered as Volume III

Influence of fructose on the diffusion of potassium hydrogen phosphate in aqueous solutions at 25 °C

International Nuclear Information System (INIS)

Verissimo, Luis M.P.; Teigão, Joana M.M.; Ramos, M. Luísa; Burrows, Hugh D.; Esteso, Miguel A.; Ribeiro, Ana C.F.

2016-01-01

Highlights: • Diffusion coefficients of aqueous systems of fructose and potassium hydrogen phosphate measured with Lobo’s cell. • Influence of the fructose on the diffusion of potassium hydrogen phosphate. • Interactions between of hydrogen phosphate anion and fructose. - Abstract: Diffusion coefficients have been measured at 25 °C for potassium hydrogen phosphate (K_2HPO_4, 0.101 mol kg"−"1) in aqueous solutions containing various concentrations of fructose from (0.001 to 0.101) mol kg"−"1, using a conductimetric cell (the Lobo cell) coupled to an automatic data acquisition system. Significant effects of fructose were observed on the diffusion of K_2HPO_4 in these mixtures, which are attributed to the interaction between HPO_4"2"− anion (or other protonated forms) and fructose. Support for this comes from "1H and "1"3C NMR spectroscopy, which are compatible with binding between the anomeric forms of D-fructose and the HPO_4"2"− anion.

Local drainage analyses of the Paducah and Portsmouth Gaseous Diffusion Plants during an extreme storm

International Nuclear Information System (INIS)

Johnson, R.O.; Wang, J.C.; Lee, D.W.

1993-01-01

Local drainage analyses have been performed for the Paducah and Portsmouth Gaseous Diffusion Plants during an extreme storm having an approximate 10,000-yr recurrence interval. This review discusses the methods utilized to accomplish the analyses in accordance with US Department of Energy (DOE) design and evaluation guidelines, and summarizes trends, results, generalizations, and uncertainties applicable to other DOE facilities. Results indicate that some culverts may be undersized, and that the storm sewer system cannot drain the influx of precipitation from the base of buildings. Roofs have not been designed to sustain ponding when the primary drainage system is clogged. Some underground tunnels, building entrances, and ground level air intakes may require waterproofing

Meteorological effects of the mechanical-draft cooling towers of the Oak Ridge Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Hanna, S.R.

1975-01-01

The mechanical-draft cooling towers at the Oak Ridge Gaseous Diffusion Plant dissipate about 2000 MW of heat. Downwash occurs about 40 percent of the time, when wind speeds exceed about 3 m/sec. An elevated cloud forms about 10 percent of the time. The length of the visible plume, which is typically 100 or 200 m, is satisfactorily modeled if it is assumed that the plumes from all the cells in a cooling-tower bank combine. The calculation of fog concentration is complicated by the fact that the moisture is not inert but is taking part in the energy exchanges of a thermodynamic system. Calculations of drift deposition agree fairly well with observations

Construction and operation of an industrial solid waste landfill at Portsmouth Gaseous Diffusion Plant, Piketon, Ohio

Energy Technology Data Exchange (ETDEWEB)

NONE

1995-10-01

The US Department of Energy (DOE), Office of Waste Management, proposes to construct and operate a solid waste landfill within the boundary of the Portsmouth Gaseous Diffusion Plant (PORTS), Piketon, Ohio. The purpose of the proposed action is to provide PORTS with additional landfill capacity for non-hazardous and asbestos wastes. The proposed action is needed to support continued operation of PORTS, which generates non-hazardous wastes on a daily basis and asbestos wastes intermittently. Three alternatives are evaluated in this environmental assessment (EA): the proposed action (construction and operation of the X-737 landfill), no-action, and offsite shipment of industrial solid wastes for disposal.

Construction and operation of an industrial solid waste landfill at Portsmouth Gaseous Diffusion Plant, Piketon, Ohio

International Nuclear Information System (INIS)

1995-10-01

The US Department of Energy (DOE), Office of Waste Management, proposes to construct and operate a solid waste landfill within the boundary of the Portsmouth Gaseous Diffusion Plant (PORTS), Piketon, Ohio. The purpose of the proposed action is to provide PORTS with additional landfill capacity for non-hazardous and asbestos wastes. The proposed action is needed to support continued operation of PORTS, which generates non-hazardous wastes on a daily basis and asbestos wastes intermittently. Three alternatives are evaluated in this environmental assessment (EA): the proposed action (construction and operation of the X-737 landfill), no-action, and offsite shipment of industrial solid wastes for disposal

Gamma radiological surveys of the Oak Ridge Reservation, Paducah Gaseous Diffusion Plant, and Portsmouth Gaseous Diffusion Plant, 1990-1993, and overview of data processing and analysis by the Environmental Restoration Remote Sensing Program, Fiscal Year 1995

International Nuclear Information System (INIS)

Smyre, J.L.; Moll, B.W.; King, A.L.

1996-06-01

Three gamma radiological surveys have been conducted under auspices of the ER Remote Sensing Program: (1) Oak Ridge Reservation (ORR) (1992), (2) Clinch River (1992), and (3) Portsmouth Gaseous Diffusion Plant (PORTS) (1993). In addition, the Remote Sensing Program has acquired the results of earlier surveys at Paducah Gaseous Diffusion Plant (PGDP) (1990) and PORTS (1990). These radiological surveys provide data for characterization and long-term monitoring of U.S. Department of Energy (DOE) contamination areas since many of the radioactive materials processed or handled on the ORR, PGDP, and PORTS are direct gamma radiation emitters or have gamma emitting daughter radionuclides. High resolution airborne gamma radiation surveys require a helicopter outfitted with one or two detector pods, a computer-based data acquisition system, and an accurate navigational positioning system for relating collected data to ground location. Sensors measure the ground-level gamma energy spectrum in the 38 to 3,026 KeV range. Analysis can provide gamma emission strength in counts per second for either gross or total man-made gamma emissions. Gross count gamma radiation includes natural background radiation from terrestrial sources (radionuclides present in small amounts in the earth's soil and bedrock), from radon gas, and from cosmic rays from outer space as well as radiation from man-made radionuclides. Man-made count gamma data include only the portion of the gross count that can be directly attributed to gamma rays from man-made radionuclides. Interpretation of the gamma energy spectra can make possible the determination of which specific radioisotopes contribute to the observed man-made gamma radiation, either as direct or as indirect (i.e., daughter) gamma energy from specific radionuclides (e.g., cesium-137, cobalt-60, uranium-238)

Concentration transients in a gaseous diffusion plant (1961); Cinetique des concentrations dans une usine de separation isotopique (1961)

Energy Technology Data Exchange (ETDEWEB)

Jacques, R; Bilous, O [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1961-07-01

Concentration transients are examined in the case of a gaseous diffusion plant for uranium isotope separation. An application is made for a plant built with two rectifying cascades of different sizes and a stripping cascade. Transients are calculated for a change in the feed concentration, the transport and also for shutdown of a group of separating stages in one of the cascades. (authors) [French] On examine l'evolution des concentrations dans une usine de separation isotopique de l'uranium basee sur le procede de diffusion gazeuse et formee de cascades carrees. Une application est faite pour une installation formee de deux cascades enrichissantes de tailles differentes et d'une cascade appauvrissante. On calcule en particulier les regimes transitoires apres variation de la concentration d'alimentation, du transport et apres mise hors circuit d'un groupe d'etages dans l'une des cascades. (auteurs)

Operating experience with aluminum bearings at the Portsmouth Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Langebrake, C.O.

1975-01-01

Considerable operating experience has been gained at the Portsmouth Gaseous Diffusion Plant over the last 15 years in the use of aluminum bearings in process related and auxiliary equipment. All of this experience has been excellent and, in several cases, the use of this type of bearing material has solved significant operating problems. Aluminum 850-T101 alloy was first used as a bearing material in purge cascade (PC-9) centrifugal compressors where a fatigue problem was being experienced with babbitt-type bearings. Good experience in this application led to the extended use of this bearing material in other equipment including process related as well as auxiliary equipment. Since 1961 aluminum bearings have been installed in approximately 21 Type PC-9 (centrifugal), 97 Type 9 (centrifugal), 262 Type X-29 (axial), and 101 Type 31 (axial) compressors, and 3 speed increasers in the X-330 Evacuation Booster Station. Based on successful operation of these bearings, continued and expanded use of aluminum bearings is recommended as a means of obtaining a high fatigue resistant bearing at a cost lower than that for babbitt-type bearings. (U.S.)

Martin Marietta Paducah Gaseous Diffusion Plant comprehensive earthquake emergency management program

International Nuclear Information System (INIS)

1990-01-01

Recognizing the value of a proactive, integrated approach to earthquake preparedness planning, Martin Marietta Energy Systems, Inc. initiated a contract in June 1989 with Murray State University, Murray, Kentucky, to develop a comprehensive earthquake management program for their Gaseous Diffusion Plant in Paducah, Kentucky (PGDP -- Subcontract No. 19P-JV649V). The overall purpose of the program is to mitigate the loss of life and property in the event of a major destructive earthquake. The program includes four distinct (yet integrated) components: an emergency management plan, with emphasis on the catastrophic earthquake; an Emergency Operations Center Duty Roster Manual; an Integrated Automated Emergency Management Information System (IAEMIS); and a series of five training program modules. The PLAN itself is comprised of four separate volumes: Volume I -- Chapters 1--3; Volume II -- Chapters 4--6, Volume III -- Chapter 7, and Volume IV -- 23 Appendices. The EOC Manual (which includes 15 mutual aid agreements) is designated as Chapter 7 in the PLAN and is a ''stand alone'' document numbered as Volume III. This document, Volume II, discusses methodology, engineering and environmental analyses, and operational procedures

Martin Marietta Paducah Gaseous Diffusion Plant comprehensive earthquake emergency management program

International Nuclear Information System (INIS)

1990-01-01

Recognizing the value of a proactive, integrated approach to earthquake preparedness planning, Martin Marietta Energy Systems, Inc, initiated a contract in June 1989 with Murray State University, Murray, Kentucky, to develop a comprehensive earthquake management program for their Gaseous Diffusion Plant in Paducah, Kentucky (PGDP--Subcontract No. 19P-JV649V). The overall purpose of the program is to mitigate the loss of life and property in the event of a major destructive earthquake. The program includes four distinct (yet integrated) components: (1) an emergency management plan, with emphasis on the catas trophic earthquake, (2) an Emergency Operations Center Duty Roster Manual, (3) an Integrated Automated Emergency Management Information System (IAEMIS), and (4) a series of five training program modules. The PLAN itself is comprised of four separate volumes: Volume I--Chapters 1--3; Volume II--Chapters 4--6, Volume III--Chapter 7, and Volume IV--23 Appendices. The EOC Manual (which includes 15 mutual aid agreements) is designated as Chapter 7 in the PLAN and is a ''stand alone'' document numbered as Volume III. This document, Volume IV contains the appendices to this report

Embrittlement of the alloy U 7.5 Nb 2.5 Zr by gaseous oxygen and hydrogen

International Nuclear Information System (INIS)

Lepoutre, D.; Nomine, A.M.; Miannay, D.

1981-04-01

Embrittlement of the alloy uranium 7.5 niobium 2.5 zirconium in gaseous oxygen and hydrogen versus stress intensity, temperature and pressure is studied using rupture mechanics. Cracking speed is determined. In oxygen, only cracks are produced and embrittlement is due to oxidation. In hydrogen at high pressure an hydride is formed and at low pressure cracks are produced but the mechanism is not identified [fr

Stable isotope enrichment by thermal diffusion

International Nuclear Information System (INIS)

Vasaru, Gheorghe

2003-01-01

Thermal diffusion (TD) in both gaseous and liquid phase has been the subject of extensive experimental and theoretical investigations, especially after the invention by K. Clusius and G. Dickel of the thermal diffusion column, sixty years ago. This paper gives a brief overview of the most important applications and developments of this transport phenomenon for enrichment of 13 C and of some noble gases isotopes in our institute. The results of calculations of the transport coefficients H and K for a concentric tube type TD column, operated with methane as process gas, are presented. Static separation factor at equilibrium vs gas pressure has been calculated for various molecular models. The experimental separation factors for different gas pressure were found to be consistent with those calculated for the inverse power repulsion model and the Lennard-Jones model. The most important characteristics of a seven-stage cascade consisting of 19 TD columns of concentric tube type are given. This system has been constructed and successfully operated at a temperature of 673 K and produces an enrichment of methane of natural isotopic 13 C abundance, up to the concentration of 25% 13 CH 4 . Enrichment of the noble gases isotopes implies: - a . Enrichment of 20 Ne and 22 Ne in a eight-stage cascade consisting of 8 TD columns; - b. enrichment of 46 Ar in a seven-stage cascade consisting of TD columns and finally; - c. enrichment of 78 Kr and 86 Kr in a fifteen-stage cascade, consisting of 35 TD columns. For all these installations we have adopted TD columns of hot wire type (4 m in length), operated at a temperature of 1073 K. (author)

Regional flood hazard assessment of the Paducah and Portsmouth Gaseous Diffusion Plants

International Nuclear Information System (INIS)

Johnson, R.O.; Wang, J.C.; Lee, D.W.

1991-01-01

Regional flood-hazard assessments performed for the Paducah and Portsmouth Gaseous Diffusion Plants are reviewed, compared, and contrasted to determine the relationship of probable maximum flood methodology with respect to US Department of Energy design and evaluation guidelines. The Paducah assessment was carried out using probable minimum flood methodology, while the Portsmouth assessment utilized probabilistic techniques. Results indicated that regional flooding along nearby rivers would not inundate either plant, and that the guidelines were satisfied. A comparison of results indicated that the probable minimum flood recurrence interval associated with the Paducah assessment exceeded the 10,000-year requirement of the guidelines, while recurrence intervals obtained in the Portsmouth assessment could be above or below 10,000 years depending on the choice of the probabilistic model used to perform the assessment. It was concluded, based on an analysis of two data points, that smaller watersheds driven by single event storms could be assessed using probabilistic techniques, while probable maximum flood methodology could be applied to larger drainage basins flooded by storm sequences

Modification and expansion of X-7725A Waste Accountability Facility for storage of polychlorinated biphenyl wastes at Portsmouth Gaseous Diffusion Plant, Piketon, Ohio

International Nuclear Information System (INIS)

1995-11-01

The US Department of Energy (DOE) must manage wastes containing polychlorinated biphenyls (PCBs) in accordance with Toxic Substances Control Act (TSCA) requirements and as prescribed in a Federal Facilities Compliance Agreement (FFCA) between DOE and the U.S. Environmental Protection Agency (EPA). PCB-containing wastes are currently stored in the PORTS process buildings where they are generated. DOE proposes to modify and expand the Waste Accountability facility (X-7725A) at the Portsmouth Gaseous Diffusion Plant (PORTS), Piketon, Ohio, to provide a central storage location for these wastes. The proposed action is needed to eliminate the fire and safety hazards presented by the wastes. In this EA, DOE considers four alternatives: (1) no action, which requires storing wastes in limited storage areas in existing facilities; (2) modifying and expanding the X-7725A waste accountability facility; (3) constructing a new PCB waste storage building; and (4) shipping PCB wastes to the K-25 TSCA incinerator. If no action is taken, PCB-contaminated would continue to be stored in Bldgs X-326, X-330, and X-333. As TSCA cleanup activities continue, the quantity of stored waste would increase, which would subsequently cause congestion in the three process buildings and increase fire and safety hazards. The preferred alternative is to modify and expand Bldg. X-7725A to store wastes generated by TSCA compliance activities. Construction, which could begin as early as April 1996, would last approximately five to seven months, with a total peak work force of 70

Potassium self-diffusion in a K-rich single-crystal alkali feldspar

CERN Document Server

Hergemöller, Fabian; Deicher, Manfred; Wolf, Herbert; Brenner, Florian; Hutter, Herbert; Abart, Rainer; Stolwijk, Nicolaas A.

The paper reports potassium diffusion measurements performed on gem-quality single-crystal alkali feldspar in the temperature range from 1169 to 1021 K. Natural sanidine from Volkesfeld, Germany was implanted with {}^{43}K at the ISOLDE/CERN radioactive ion-beam facility normal to the (001) crystallographic plane. Diffusion coefficients are well described by the Arrhenius equation with an activation energy of 2.4 eV and a pre-exponential factor of 5×10^{-6}m^{2}/s, which is more than three orders of magnitude lower than the {}^{22}Na diffusivity in the same feldspar and the same crystallographic direction. State-of-the-art considerations including ionic conductivity data on the same crystal and Monte Carlo simulations of diffusion in random binary alloy structures point to a correlated motion of K and Na through the interstitialcy mechanism.

Separation of tritium from gaseous and aqueous effluent systems

International Nuclear Information System (INIS)

Kobisk, E.H.

1977-01-01

Removal or reduction of tritium content in a wide variety of effluent streams has been extensively studied in the United States. This paper specifically reviews three processes involving tritium separation in the gaseous phase and the aqueous phase. Diffusion through a selective Pd-25Ag alloy membrane at temperatures up to 600 0 C and at pressures up to 700 kg/cm 2 has resulted in successful separation of hydrogen-deuterium mixtures with an associated separation factor of 1.65 (and gives a calculated separation factor for hydrogen-tritium mixtures of 2.0). Use of a single palladium bipolar membrane in an electrolysis system has been found to yield a hydrogen-deuterium separation factor of 4 and a hydrogen-tritium factor of 6 to 11 without the production of gaseous hydrogen. Finally, countercurrent catalytic exchange between tritium-containing hydrogen gas and water has yielded a separation factor of 6.3. The specific advantages of each of these systems will be discussed in terms of their potential applications. In all cases, further investigations are necessary to scale the systems to handle large quantities of feed material in a continuous mode and to minimize energy requirements. Such separative systems must necessarily be cascaded to yield gaseous or aqueous product streams suitable for recycling to the tritium producing systems, for storage or for discharge to the environment. (orig./HP) [de

A probabilistic safety analysis of UF{sub 6} handling at the Portsmouth Gaseous Diffusion Plant

Energy Technology Data Exchange (ETDEWEB)

Boyd, G.J.; Lewis, S.R.; Summitt, R.L. [Safety and Reliability Optimization Services (SAROS), Inc., Knoxville, TN (United States)

1991-12-31

A probabilistic safety study of UF{sub 6} handling activities at the Portsmouth Gaseous Diffusion Plant has recently been completed. The analysis provides a unique perspective on the safety of UF{sub 6} handling activities. The estimated release frequencies provide an understanding of current risks, and the examination of individual contributors yields a ranking of important plant features and operations. Aside from the probabilistic results, however, there is an even more important benefit derived from a systematic modeling of all operations. The integrated approach employed in the analysis allows the interrelationships among the equipment and the required operations to be explored in depth. This paper summarizes the methods used in the study and provides an overview of some of the technical insights that were obtained. Specific areas of possible improvement in operations are described.

Prioritizing and scheduling Portsmouth Gaseous Diffusion Plant safeguards upgrades

International Nuclear Information System (INIS)

Edmunds, T.; Saleh, R.; Zevanove, S.

1992-02-01

As part of the Site Safeguards and Security Plan (SSSP), facilities are required to develop a Resource Plan (RP). The Resource Plan provides documentation and justification for the facility's planned upgrades, including the schedule, priority, and cost estimates for the safeguards and security upgrades. Portsmouth Gaseous Diffusion Plant (PORTS) management has identified and obtained funding approval for a number of safeguards and security upgrades, including line-item construction projects. These upgrade projects were selected to address a variety of concerns identified in the PORTS vulnerability assessments and other reviews performed in support of the SSSP process. However, budgeting and scheduling constraints do not make it possible to simultaneously begin implementation of all of the upgrade projects. A formal methodology and analysis are needed to explicitly address the trade-offs between competing safeguards objectives, and to prioritize and schedule the upgrade projects to ensure that the maximum benefit can be realized in the shortest possible time frame. The purpose of this report is to describe the methodology developed to support these upgrade project scheduling decisions. The report also presents the results obtained from applying the methodology to a set of the upgrade projects selected by PORTS S ampersand S management. Data for the analysis are based on discussions with personnel familiar with the PORTS safeguards and security needs, the requirements for implementing these upgrades, and upgrade funding limitations. The analysis results presented here assume continued highly enriched uranium (HEU) operations at PORTS. However, the methodology developed is readily adaptable for the evaluation of other operational scenarios and other resource allocation issues relevant to PORTS

Relationship between timed 25-foot walk and diffusion tensor imaging in multiple sclerosis.

Science.gov (United States)

Klineova, Sylvia; Farber, Rebecca; Saiote, Catarina; Farrell, Colleen; Delman, Bradley N; Tanenbaum, Lawrence N; Friedman, Joshua; Inglese, Matilde; Lublin, Fred D; Krieger, Stephen

2016-01-01

The majority of multiple sclerosis patients experience impaired walking ability, which impacts quality of life. Timed 25-foot walk is commonly used to gauge gait impairment but results can be broadly variable. Objective biological markers that correlate closely with patients' disability are needed. Diffusion tensor imaging, quantifying fiber tract integrity, might provide such information. In this project we analyzed relationships between timed 25-foot walk, conventional and diffusion tensor imaging magnetic resonance imaging markers. A cohort of gait impaired multiple sclerosis patients underwent brain and cervical spinal cord magnetic resonance imaging. Diffusion tensor imaging mean diffusivity and fractional anisotropy were measured on the brain corticospinal tracts and spinal restricted field of vision at C2/3. We analyzed relationships between baseline timed 25-foot walk, conventional and diffusion tensor imaging magnetic resonance imaging markers. Multivariate linear regression analysis showed a statistically significant association between several magnetic resonance imaging and diffusion tensor imaging metrics and timed 25-foot walk: brain mean diffusivity corticospinal tracts (p = 0.004), brain corticospinal tracts axial and radial diffusivity (P = 0.004 and 0.02), grey matter volume (p = 0.05), white matter volume (p = 0.03) and normalized brain volume (P = 0.01). The linear regression model containing mean diffusivity corticospinal tracts and controlled for gait assistance was the best fit model (p = 0.004). Our results suggest an association between diffusion tensor imaging metrics and gait impairment, evidenced by brain mean diffusivity corticospinal tracts and timed 25-foot walk.

Some aspects of numerical analysis of turbulent gaseous and spray combustion

International Nuclear Information System (INIS)

Takagi, T.

1991-01-01

In this paper numerical calculations and analysis on turbulent non-premixed gaseous and spray combustion are reviewed. Attentions were paid to the turbulent flow and combustion modeling applicable to predicting the flow, mixing and combustion of gaseous fuels and sprays. Some of the computed results of turbulent gaseous non-premixed (diffusion) flames with and without swirl and transient spray combustion were compared with experimental ones to understand the processes in the flame and to assure how the computations predict the experiments

PM2.5 and gaseous pollutants in New York State during 2005-2016: Spatial variability, temporal trends, and economic influences

Science.gov (United States)

Squizzato, Stefania; Masiol, Mauro; Rich, David Q.; Hopke, Philip K.

2018-06-01

Over the past decades, mitigation strategies have been adopted both by federal and state agencies in the United States (US) to improve air quality. Between 2007 and 2009, the US faced a financial/economic crisis that lowered activity and reduced emissions. At the same time, changes in the prices of coal and natural gas drove a shift in fuels used for electricity generation. Seasonal patterns, diel cycles, spatial gradients, and trends in PM2.5 and gaseous pollutants concentrations (NOx, SO2, CO and O3) monitored in New York State (NYS) from 2005 to 2016 were examined. Relationships between ambient concentrations, changes in NYS emissions retrieved from the US EPA trends inventory, and economic indicators were studied. PM2.5 and primary gaseous pollutants concentrations decreased across NYS. By 2016, PM2.5 and SO2 attained relatively homogeneous concentrations across the state. PM2.5 concentrations decreased significantly at all sites. Similarly, SO2 concentrations declined at all sites within this period, with the highest slopes observed at the urban sites. Reductions in NOx emissions likely contributed to summertime average ozone reductions. NOx and VOCs controls reduced O3 peak concentrations as seen in significant relationships between the annual O3 4th-highest daily maximum 8-h concentrations and estimated NOx emissions at rural and suburban sites (r2 ∼ 0.7). Spring maxima were not reduced with most sites showing insignificant slopes or significant positive slopes (e.g., +2.6% y-1 and +2% y-1, at CCNY and PFI, respectively). Increases in autumn and winter ozone concentrations were found (e,g., 6.6 ± 0.4% y-1 on average in New York City). Significant relationships were observed between PM2.5, primary pollutants, and economic indicators. Overall, a decrease in electricity generation with coal, and the simultaneous increase in natural gas consumption for power generation, led to a decrease in PM2.5 and gaseous pollutants concentrations.

Economic study of an installation for uranium isotope separation by gaseous diffusion; Etude economique d'une installation de separation des isotopes de l'uranium par diffusion gazeuse

Energy Technology Data Exchange (ETDEWEB)

Bilous, O [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1958-07-01

This report describes the major problems which arise in the choice of characteristics required in a gaseous diffusion installation for the separation of uranium isotopes. This choice depends largely on economic evaluations, and also on considerations of simplicity. The choice of working pressures and of the characteristics of the membrane are described, as are the possible alternatives regarding the structure of the stages and the problems of control. (author) [French] Ce rapport decrit les problemes majeurs qui se posent dans le choix des caracteristiques d'une installation de diffusion gazeuse destinee a la separation des isotopes de l'uranium. Ce choix depend en grande partie d'evaluations economiques et repose egalement sur des considerations de simplicite. On decrit ainsi le choix des pressions d'operation, celui des caracteristiques de la barriere, les alternatives possibles concernant la structure des etages et les problemes de regulation. (auteur)

Biodenitrification of gaseous diffusion plant aqueous wastes: stirred bed reactor

International Nuclear Information System (INIS)

Holland, M.E.

1980-01-01

Approximately 30 kilograms of nitrates per day are discarded in the raffinates (acid wastes) of the Portsmouth Gaseous Diffusion Plant's X-705 Uranium Recovery and Decontamination Facility. A biodenitrification process employing continuous-flow, stirred-bed reactors has been successfully used to remove nitrates from similar acid wastes at the Oak Ridge Y-12 Plant. Laboratory studies have been made at Portsmouth to characterize the X-705 raffinates and to test the stirred-bed biodenitrification process on such raffinates. Raffinates which had been previously characterized were pumped through continuous-flow, stirred-bed, laboratory-scale reactors. Tests were conducted over a period of 146 days and involved variations in composition, mixing requirements, and the fate of several metal ions in the raffinates. Tests results show that 20 weight percent nitrates were reduced to a target nitrate effluent concentration of 100 μg/ml with a 99.64 percent efficiency. However, the average denitrification rate achieved was only 33% of that demonstrated with the Y-12 stirred-bed system. These low rates were probably due to the toxic effects of heavy metal ions on the denitrifying bacteria. Also, most of the uranium in the raffinate feed remained in the biomass and calcite, which collected in the reactor. This could cause criticality problems. For these reasons, it was decided not to make use of the stirred-bed bioreactor at Portsmouth. Instead, the biodenitrification installation now planned will use fluidized bed columns whose performance will be the subject of a subsequent report

In-Situ Measurements of Low Enrichment Uranium Holdup Process Gas Piping at K-25 - Paper for Waste Management Symposia 2010 East Tennessee Technology Park Oak Ridge, Tennessee

International Nuclear Information System (INIS)

Rasmussen, B.

2010-01-01

This document is the final version of a paper submitted to the Waste Management Symposia, Phoenix, 2010, abstract BJC/OR-3280. The primary document from which this paper was condensed is In-Situ Measurement of Low Enrichment Uranium Holdup in Process Gas Piping at K-25 Using NaI/HMS4 Gamma Detection Systems, BJC/OR-3355. This work explores the sufficiency and limitations of the Holdup Measurement System 4 (HJVIS4) software algorithms applied to measurements of low enriched uranium holdup in gaseous diffusion process gas piping. HMS4 has been used extensively during the decommissioning and demolition project of the K-25 building for U-235 holdup quantification. The HMS4 software is an integral part of one of the primary nondestructive assay (NDA) systems which was successfully tested and qualified for holdup deposit quantification in the process gas piping of the K-25 building. The initial qualification focused on the measurement of highly enriched UO 2 F 2 deposits. The purpose of this work was to determine if that qualification could be extended to include the quantification of holdup in UO 2 F 2 deposits of lower enrichment. Sample field data are presented to provide evidence in support of the theoretical foundation. The HMS4 algorithms were investigated in detail and found to sufficiently compensate for UO 2 F 2 source self-attenuation effects, over the range of expected enrichment (4-40%), in the North and East Wings of the K-25 building. The limitations of the HMS4 algorithms were explored for a described set of conditions with respect to area source measurements of low enriched UO 2 F 2 deposits when used in conjunction with a 1 inch by 1/2 inch sodium iodide (NaI) scintillation detector. The theoretical limitations of HMS4, based on the expected conditions in the process gas system of the K-25 building, are related back to the required data quality objectives (DQO) for the NBA measurement system established for the K-25 demolition project. The combined

7th International Symposium on Gaseous Dielectrics

CERN Document Server

James, David

1994-01-01

The Seventh International Symposium on Gaseous Dielectrics was held in Knoxville, Tennessee, U. S. A. , on April 24-28, 1994. The symposium continued the interdisciplinary character and comprehensive approach of the preceding six symposia. Gaseous DielecIries VII is a detailed record of the symposium proceedings. It covers recent advances and developments in a wide range of basic, applied and industrial areas of gaseous dielectrics. It is hoped that Gaseous DielecIries VII will aid future research and development in, and encourage wider industrial use of, gaseous dielectrics. The Organizing Committee of the Seventh International Symposium on Gaseous Dielectrics consisted of G. Addis (U. S. A. ), L. G. Christophorou (U. S. A. ), F. Y. Chu (Canada), A. H. Cookson (U. S. A. ), O. Farish (U. K. ), I. Gallimberti (Italy) , A. Garscadden (U. S. A. ), D. R. James (U. S. A. ), E. Marode (France), T. Nitta (Japan), W. Pfeiffer (Germany), Y. Qiu (China), I. Sauers (U. S. A. ), R. J. Van Brunt (U. S. A. ), and W. Zaengl...

Environmental program audit: Oak Ridge Gaseous Diffusion Plant, Roane County, Tennessee. Final report

International Nuclear Information System (INIS)

Smith, W.M.; Waller, R.

1985-01-01

An environmental audit of the Oak Ridge Gaseous Diffusion Plant (ORGDP) was conducted by a team of NUS scientists and engineers during the week of June 3 through June 7, 1985. ORGDP is owned by the Department of Energy and operated by Martin-Marietta Energy Systems, Inc. To enrich uranium feedstocks for nuclear fuels. The team evaluated ORGDP in terms of compliance with environmental regulations and DOE Orders, the adequacy of pollution control equipment, the effectiveness of environmental monitoring, and the application of quality control procedures to environmental programs. The audit was conducted by observing operations, inspecting facilities, evaluating analysis and monitoring techniques, reviewing reports and data, and interviewing personnel. Overall, the ORGDP environmental program appears to be well structured and has attempted to address all areas of air, water, and land media likely to be affected by the operations of the facility. The plant management is knowledgeable about environmental concerns and has established clear, well-defined goals to address these areas. An adequate professional staff is available to manage the environmental program

Replacement of chlorofluorocarbons at the DOE gaseous diffusion plants: An assessment of global impacts

International Nuclear Information System (INIS)

Socolof, M.L.; McCold, L.N.; Saylor, R.E.

1997-01-01

Three gaseous diffusion plants (GDPs) for enriching uranium maintain a large inventory of chlorofluorocarbon-114 (CFC-114) as a coolant. To address the continued use of CFC-114, an ozone-depleting substance, the US Department of Energy (DOE) considered introducing perfluorocarbons (PFCs) by the end of 1995. These PFCs would not contribute to stratospheric ozone depletion but would be larger contributors to global warming than would CFC-114. The paper reports the results of an assessment of the global impacts of four alternatives for modifying GDP coolant system operations over a three-year period beginning in 1996. The overall contribution of GDP coolant releases to impacts on ozone depletion and global warming were quantified by parameters referred to as ozone-depletion impact and global-warming impact. The analysis showed that these parameters could be used as surrogates for predicting global impacts to all resources and could provide a framework for assessing environmental impacts of a permanent coolant replacement, eliminating the need for subsequent resource-specific analyses

A study on the diffusion of gaseous radioactive effluents based on the statistical method

International Nuclear Information System (INIS)

Na, Man Gyun; Lee, Goung Jin

1998-01-01

A diffusion model of radioactive gaseous effluents is improved to apply for domestic nuclear power plants. Up to now, XOQDOQ computer code package developed by U. S NRC has been used for the assessment of radioactive plume dispersion by normal operation of domestic nuclear power plants. XOQDOQ adopts the straight-line Gaussian plume model which was basically derived for the plane terrain. However, since there are so many mountains in Korea, the several shortcomings of XOQDOQ are improved to consider the complex terrain effects. In this work, wind direction change is considered by modifying the wind rose frequency using meteorological data of the local weather stations. In addition, an effective height correction model, a plume reduction model due to plume penetration into mountain, and a wet deposition model are adopted for more realistic assessments. The proposed methodology is implemented in Yonggwang nuclear power plants, and can be used for other domestic nuclear power plants

Determination of activation energy of hydrogen diffusion in Zr-2.5%Nb alloy

International Nuclear Information System (INIS)

Chandra, Komal; Kulkarni, A.S.; Ramanjaneyulu, P.S.; Yadav, C.S.; Saxena, M.K.; Tomar, B.S.; Ramakumar, K.L.; Sunil, Sourav; Singh, R.N.

2013-01-01

The present paper describes the study on the determination of diffusion coefficient of hydrogen in Zr-2.5%Nb alloy. Hydrogen was charged on Zr-2.5% Nb alloy electrolytically. After annealing at required temperature, hydrogen concentration at various depths from the charged end was determined employing hot vacuum extraction-quadrupole mass spectrometer (HVE-QMS). The depth profile was used to obtain the diffusion coefficient employing Fick's second law of diffusion. From the Arrhenius relation between diffusion coefficient and temperature, activation energy of hydrogen diffusion was calculated. (author)

Kinetic Monte Carlo Simulation of Cation Diffusion in Low-K Ceramics

Science.gov (United States)

Good, Brian

2013-01-01

Low thermal conductivity (low-K) ceramic materials are of interest to the aerospace community for use as the thermal barrier component of coating systems for turbine engine components. In particular, zirconia-based materials exhibit both low thermal conductivity and structural stability at high temperature, making them suitable for such applications. Because creep is one of the potential failure modes, and because diffusion is a mechanism by which creep takes place, we have performed computer simulations of cation diffusion in a variety of zirconia-based low-K materials. The kinetic Monte Carlo simulation method is an alternative to the more widely known molecular dynamics (MD) method. It is designed to study "infrequent-event" processes, such as diffusion, for which MD simulation can be highly inefficient. We describe the results of kinetic Monte Carlo computer simulations of cation diffusion in several zirconia-based materials, specifically, zirconia doped with Y, Gd, Nb and Yb. Diffusion paths are identified, and migration energy barriers are obtained from density functional calculations and from the literature. We present results on the temperature dependence of the diffusivity, and on the effects of the presence of oxygen vacancies in cation diffusion barrier complexes as well.

Report on the Biological Monitoring Program at Paducah Gaseous Diffusion Plant December 1992--December 1993

Energy Technology Data Exchange (ETDEWEB)

Kszos, L.A.; Hinzman, R.L.; Peterson, M.J.; Ryon, M.G.; Smith, J.G.; Southworth, G.R.

1995-06-01

On September 24, 1987, the Commonwealth of Kentucky Natural Resources and Environmental Protection Cabinet issued an Agreed Order that required the development of a Biological Monitoring Program (BMP) for the Paducah Gaseous Diffusion Plant (PGDP). The goals of BMP are to demonstrate that the effluent limitations established for PGDP protect and maintain the use of Little Bayou and Big Bayou creeks for growth and propagation of fish and other aquatic life, characterize potential health and environmental impacts, document the effects of pollution abatement facilities on stream biota, and recommend any program improvements that would increase effluent treatability. The BMP for PGDP consists of three major tasks: effluent and ambient toxicity monitoring, bioaccumulation studies, and ecological surveys of stream communities (i.e., benthic macroinvertebrates and fish). This report includes ESD activities occurring from December 1992 to December 1993, although activities conducted outside this time period are included as appropriate.

Glutathionylation-Dependence of Na+-K+-Pump Currents Can Mimic Reduced Subsarcolemmal Na+ Diffusion

Science.gov (United States)

Garcia, Alvaro; Liu, Chia-Chi; Cornelius, Flemming; Clarke, Ronald J.; Rasmussen, Helge H.

2016-01-01

The existence of a subsarcolemmal space with restricted diffusion for Na+ in cardiac myocytes has been inferred from a transient peak electrogenic Na+-K+ pump current beyond steady state on reexposure of myocytes to K+ after a period of exposure to K+-free extracellular solution. The transient peak current is attributed to enhanced electrogenic pumping of Na+ that accumulated in the diffusion-restricted space during pump inhibition in K+-free extracellular solution. However, there are no known physical barriers that account for such restricted Na+ diffusion, and we examined if changes of activity of the Na+-K+ pump itself cause the transient peak current. Reexposure to K+ reproduced a transient current beyond steady state in voltage-clamped ventricular myocytes as reported by others. Persistence of it when the Na+ concentration in patch pipette solutions perfusing the intracellular compartment was high and elimination of it with K+-free pipette solution could not be reconciled with restricted subsarcolemmal Na+ diffusion. The pattern of the transient current early after pump activation was dependent on transmembrane Na+- and K+ concentration gradients suggesting the currents were related to the conformational poise imposed on the pump. We examined if the currents might be accounted for by changes in glutathionylation of the β1 Na+-K+ pump subunit, a reversible oxidative modification that inhibits the pump. Susceptibility of the β1 subunit to glutathionylation depends on the conformational poise of the Na+-K+ pump, and glutathionylation with the pump stabilized in conformations equivalent to those expected to be imposed on voltage-clamped myocytes supported this hypothesis. So did elimination of the transient K+-induced peak Na+-K+ pump current when we included glutaredoxin 1 in patch pipette solutions to reverse glutathionylation. We conclude that transient K+-induced peak Na+-K+ pump current reflects the effect of conformation-dependent β1 pump subunit

Glutathionylation-Dependence of Na(+)-K(+)-Pump Currents Can Mimic Reduced Subsarcolemmal Na(+) Diffusion.

Science.gov (United States)

Garcia, Alvaro; Liu, Chia-Chi; Cornelius, Flemming; Clarke, Ronald J; Rasmussen, Helge H

2016-03-08

The existence of a subsarcolemmal space with restricted diffusion for Na(+) in cardiac myocytes has been inferred from a transient peak electrogenic Na(+)-K(+) pump current beyond steady state on reexposure of myocytes to K(+) after a period of exposure to K(+)-free extracellular solution. The transient peak current is attributed to enhanced electrogenic pumping of Na(+) that accumulated in the diffusion-restricted space during pump inhibition in K(+)-free extracellular solution. However, there are no known physical barriers that account for such restricted Na(+) diffusion, and we examined if changes of activity of the Na(+)-K(+) pump itself cause the transient peak current. Reexposure to K(+) reproduced a transient current beyond steady state in voltage-clamped ventricular myocytes as reported by others. Persistence of it when the Na(+) concentration in patch pipette solutions perfusing the intracellular compartment was high and elimination of it with K(+)-free pipette solution could not be reconciled with restricted subsarcolemmal Na(+) diffusion. The pattern of the transient current early after pump activation was dependent on transmembrane Na(+)- and K(+) concentration gradients suggesting the currents were related to the conformational poise imposed on the pump. We examined if the currents might be accounted for by changes in glutathionylation of the β1 Na(+)-K(+) pump subunit, a reversible oxidative modification that inhibits the pump. Susceptibility of the β1 subunit to glutathionylation depends on the conformational poise of the Na(+)-K(+) pump, and glutathionylation with the pump stabilized in conformations equivalent to those expected to be imposed on voltage-clamped myocytes supported this hypothesis. So did elimination of the transient K(+)-induced peak Na(+)-K(+) pump current when we included glutaredoxin 1 in patch pipette solutions to reverse glutathionylation. We conclude that transient K(+)-induced peak Na(+)-K(+) pump current reflects the effect

Glutathionylation-Dependence of Na+-K+-Pump Currents Can Mimic Reduced Subsarcolemmal Na+ Diffusion

OpenAIRE

Garcia, Alvaro; Liu, Chia-Chi; Cornelius, Flemming; Clarke, Ronald?J.; Rasmussen, Helge?H.

2016-01-01

The existence of a subsarcolemmal space with restricted diffusion for Na+ in cardiac myocytes has been inferred from a transient peak electrogenic Na+-K+ pump current beyond steady state on reexposure of myocytes to K+ after a period of exposure to K+-free extracellular solution. The transient peak current is attributed to enhanced electrogenic pumping of Na+ that accumulated in the diffusion-restricted space during pump inhibition in K+-free extracellular solution. However, there are no know...

Application of the electromagnetic borehole flowmeter and evaluation of previous pumping tests at Paducah Gaseous Diffusion Plant. Final report, June 15, 1992--August 31, 1992

Energy Technology Data Exchange (ETDEWEB)

Young, S.C.; Julian, S.C.; Neton, M.J.

1993-01-01

Multi-well pumping tests have been concluded at wells MW79, MW108, and PW1 at the Paducah Gaseous Diffusion Plant (PGDP) to determine the hydraulic properties of the Regional Gravel Aquifer (RGA). Soil cores suggest that the RGA consists of a thin sandy facies (2 to 6 feet) at the top of a thicker (> 10 feet) gravelly facies. Previous analyses have not considered any permeability contrast between the two facies. To assess the accuracy of this assumption, TVA personnel conducted borehole flowmeter tests at wells MW108 and PW1. Well MW79 could not be tested. The high K sand unit is probably 10 times more permeable than comparable zone in the gravelly portion of the RGA. Previous analyses of the three multi-well aquifer tests do not use the same conceptual aquifer model. Data analysis for one pumping test assumed that leakance was significant. Data analysis for another pumping test assumed that a geologic boundary was significant. By collectively analyzing all three tests with the borehole flowmeter results, the inconsistency among the three pumping tests can be explained. Disparity exists because each pumping test had a different placement of observation wells relative to the high K zone delineating by flowmeter testing.

Back from the Brink with Something for Everyone - The Final Executed Memorandum of Agreement for Interpretation of the East Tennessee Technology Park and the K-25 Building - 13370

International Nuclear Information System (INIS)

Cusick, Lesley T.

2013-01-01

When the Environmental Management (EM) Program at the Oak Ridge Office of the Department of Energy (DOE) began its major decontamination and decommissioning (D and D) program activities in the mid-1990's, it was understood that the work to demolish the gaseous diffusion process buildings at the K-25 Site, as it was then known, would be challenging. Nothing of that size and breadth had ever been done within the DOE complex and the job brought about a full menu of unique attributes: radiological contamination with enriched materials entrained in certain areas of the system, a facility that was never designed not to operate but had been shut down since 1964, and a loyal following of individuals and organizations who were committed to the physical preservation of at least some portion of the historic Manhattan Project property. DOE was able to solve and resolve the issues related to nuclear materials management, contamination control, and determining the best way to safely and efficiently deconstruct the massive building. However, for a variety of reasons, resolution of the historic preservation questions - what and how much to preserve, how to preserve it, where to preserve it, how to interpret it, how much to spend on preservation, and by and for whom preservation should occur - remained open to debate for over a decade. After a dozen years, countless meetings, phone calls, discussions and other exchanges, and four National Historic Preservation Act (NHPA) [1] Memoranda of Agreement (MOA), a final MOA [2] has been executed. The final executed MOA's measures are robust, creative, substantive, and will be effective. They include a multi-story replica of a portion of the K-25 Building, the dedication of the K-25 Building footprint for preservation purposes, an equipment building to house authentic Manhattan Project and Cold War equipment, a virtual museum, an on-site history center, a grant to preserve a historically-significant Manhattan Project-era hotel in Oak Ridge

Back from the Brink with Something for Everyone - The Final Executed Memorandum of Agreement for Interpretation of the East Tennessee Technology Park and the K-25 Building - 13370

Energy Technology Data Exchange (ETDEWEB)

Cusick, Lesley T. [Restoration Services, Inc. (United States)

2013-07-01

When the Environmental Management (EM) Program at the Oak Ridge Office of the Department of Energy (DOE) began its major decontamination and decommissioning (D and D) program activities in the mid-1990's, it was understood that the work to demolish the gaseous diffusion process buildings at the K-25 Site, as it was then known, would be challenging. Nothing of that size and breadth had ever been done within the DOE complex and the job brought about a full menu of unique attributes: radiological contamination with enriched materials entrained in certain areas of the system, a facility that was never designed not to operate but had been shut down since 1964, and a loyal following of individuals and organizations who were committed to the physical preservation of at least some portion of the historic Manhattan Project property. DOE was able to solve and resolve the issues related to nuclear materials management, contamination control, and determining the best way to safely and efficiently deconstruct the massive building. However, for a variety of reasons, resolution of the historic preservation questions - what and how much to preserve, how to preserve it, where to preserve it, how to interpret it, how much to spend on preservation, and by and for whom preservation should occur - remained open to debate for over a decade. After a dozen years, countless meetings, phone calls, discussions and other exchanges, and four National Historic Preservation Act (NHPA) [1] Memoranda of Agreement (MOA), a final MOA [2] has been executed. The final executed MOA's measures are robust, creative, substantive, and will be effective. They include a multi-story replica of a portion of the K-25 Building, the dedication of the K-25 Building footprint for preservation purposes, an equipment building to house authentic Manhattan Project and Cold War equipment, a virtual museum, an on-site history center, a grant to preserve a historically-significant Manhattan Project-era hotel in

LANMAS alpha configured for Sandia National Laboratories and Paducah Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Woychick, M.R.; Bracey, J.T.; Kern, E.A.; Alvarado, A.

1993-07-01

Los Alamos National Laboratory and the Westinghouse Hanford Company have been working jointly for the past 2 years to develop LANMAS (Local Area Network Material Accountability System), the next generation of a US Department of Energy nuclear material accountability system. LANMAS is being designed to reflect the broad-based needs of the US Department of Energy's Material Control ampersand Accountability and Nuclear Materials Management communities, and its developers believe that significant cost savings can be achieved by implementing LANMAS complex-wide, where feasible. LANMAS is being designed so that it is transportable to appropriate US Department of Energy sites. To accomplish this, LANMAS will be configurable to local site work culture. Many US Department of Energy sites are interested in the LANMAS project, and several have participated in its development; some have committed resources. The original LANMAS project team included representatives from the Hanford Site and Los Alamos. As of June 1993, the following sites have also supported the project: Sandia National Laboratory Albuquerque; Sandia National Laboratory Livermore; Paducah Gaseous Diffusion Plant; Lawrence Livermore National Laboratory; Bettis Atomic Power Laboratory; and Knolls Atomic Power Laboratory. In addition, LANMAS is being targeted as a candidate for the US Department of Energy Complex 21, a project designed to restructure the nation's nuclear weapons complex

In situ gaseous tracer diffusion experiments and predictive modeling at the Greater Confinement Disposal Test

International Nuclear Information System (INIS)

Olson, M.C.

1985-07-01

The Greater Confinement Disposal Test (GCDT) at the Nevada Test Site is a research project investigating the feasibility of augered shaft disposal of low-level radioactive waste considered unsuitable for shallow land burial. The GCDT contains environmentally mobile and high-specific-activity sources. Research is focused on providing a set of analytically derived hydrogeologic parameters and an empirical database for application in a multiphase, two-dimensional, transient, predictive performance model. Potential contaminant transport processes at the GCDT are identified and their level of significance is detailed. Nonisothermal gaseous diffusion through alluvial sediments is considered the primary waste migration process. Volatile organic tracers are released in the subsurface and their migration is monitored in situ to determine media effective diffusion coefficients, tortuosity, and sorption-corrected porosity terms. The theoretical basis for volatile tracer experiments is presented. Treatment of thermal and liquid flow components is discussed, as is the basis for eliminating several negligible transport processes. Interpretive techniques include correlation, power spectra, and least squares analysis, a graphical analytical solution, and inverse numerical modeling. Model design and application to the GCDT are discussed. GCDT structural, analytical, and computer facilities are detailed. The status of the current research program is reviewed, and temperature and soil moisture profiles are presented along with results of operational tests on the analytical system. 72 refs., 39 figs., 2 tabs

Experimental thermochemical study of 2,5- and 2,6-dichloro-4-nitroanilines

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Ribeiro da Silva, Maria D.M.C.; Lobo Ferreira, Ana I.M.C.; Santos, Ana Filipa L.O.M.; Galvao, Tiago L.P.

2009-01-01

The standard (p o = 0.1 MPa) molar enthalpies of formation of 2,5- and 2,6-dichloro-4-nitroanilines, in the gaseous phase, at T = 298.15 K, were derived from the combination of the values of the standard molar enthalpies of formation in the crystalline phase, at T = 298.15 K, and the standard molar enthalpies of sublimation, of each compound, at the same temperature. The standard molar enthalpies of formation, in the crystalline phase, at T = 298.15 K, were derived from the standard massic energies of combustion of the two isomers, in oxygen, at T = 298.15 K, measured by rotating-bomb combustion calorimetry. The standard molar enthalpies of sublimation were calculated, by application of the Clausius-Clapeyron equation, to the vapour pressures at several temperatures measured by Knudsen effusion technique. The values of the standard (p = 0.1 MPa) molar enthalpies of formation of 2,5- and 2,6-dichloro-4-nitroanilines, in the gaseous phase, at T = 298.15 K, were compared with those estimated by the Cox scheme.

Determination of diffusion coefficients of hydrogen and deuterium in Zr–2.5%Nb pressure tube material using hot vacuum extraction-quadrupole mass spectrometry

Energy Technology Data Exchange (ETDEWEB)

Shrivastava, Komal Chandra, E-mail: komal@barc.gov.in [Radioanalytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Kulkarni, A.S.; Ramanjaneyulu, P.S. [Radioanalytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Sunil, Saurav [Mechanical Metallurgy Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Saxena, M.K. [Radioanalytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Singh, R.N. [Mechanical Metallurgy Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India); Tomar, B.S.; Ramakumar, K.L. [Radioanalytical Chemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

2015-06-15

The diffusion coefficients of hydrogen and deuterium in Zr–2.5%Nb alloy were measured in the temperature range 523 to 673 K, employing hot vacuum extraction-quadrupole mass spectrometry (HVE-QMS). One end of the Zr–2.5%Nb alloy specimens was charged electrolytically with the desired hydrogen isotope. After annealing at different temperatures for a predetermined time, the specimens were cut into thin slices, which were analyzed for their H{sub 2}/D{sub 2} content using the HVE-QMS technique. The depth profile data were fitted into the equation representing the solution of Fick’s second law of diffusion. The activation energy of hydrogen/deuterium diffusion was obtained from the Arrhenius relation between the diffusion coefficient and temperature. The temperature dependent diffusion coefficient can be represented as D{sub H} = 1.41 × 10{sup −7} exp(−36,000/RT) and D{sub D} = 6.16 × 10{sup −8} exp(−35,262/RT) for hydrogen and deuterium, respectively.

Recycle of radioactive scrap metal from the Oak Ridge Gaseous Diffusion Plant (K-25 Site)

Energy Technology Data Exchange (ETDEWEB)

Meehan, R.W. [DOE-Oak Ridge Operations Office, TN (United States)

1997-02-01

The scale of the metal available for reuse at the plant includes 22 million pounds of Ni, 17 million pounds of Al, 47 million pounds of copper, and 835 million pounds of steels. In addition there is a wide range of industrial equipment and other items of value. The author describes small bench scale and pilot plant scale efforts made at treating metal for decontamination and fabrication into cast stock or specialized containers for reuse within the DOE complex or release. These projects show that much of the material can be cleaned or chemically decontaminated to a level where it can be free released to various markets. Of the remaining metals, much of it can be cast into products which can be absorbed within the DOE complex.

Creeping gaseous flows through elastic tube and annulus micro-configurations

Science.gov (United States)

Elbaz, Shai; Jacob, Hila; Gat, Amir

2016-11-01

Gaseous flows in elastic micro-configurations is relevant to biological systems (e.g. alveolar ducts in the lungs) as well as to applications such as gas actuated soft micro-robots. We here examine the effect of low-Mach-number compressibility on creeping gaseous axial flows through linearly elastic tube and annulus micro-configurations. For steady flows, the leading-order effects of elasticity on the pressure distribution and mass-flux are obtained. For transient flow in a tube with small deformations, elastic effects are shown to be negligible in leading order due to compressibility. We then examine transient flows in annular configurations where the deformation is significant compared with the gap between the inner and outer cylinders defining the annulus. Both compressibility and elasticity are obtained as dominant terms interacting with viscosity. For a sudden flux impulse, the governing non-linear leading order diffusion equation is initially approximated by a porous-medium-equation of order 2.5 for the pressure square. However, as the fluid expand and the pressure decreases, the governing equation degenerates to a porous-medium-equation of order 2 for the pressure.

An aerial radiological survey of the Portsmouth Gaseous Diffusion Plant and surrounding area

International Nuclear Information System (INIS)

Sampoll-Ramirez, G.

1994-09-01

An aerial radiological survey was conducted from August 10-16, 1993, over a 78-square-kilometer (30-square-mile) area of the Portsmouth Gaseous Diffusion Plant and surrounding area located near Portsmouth, Ohio. The survey was performed at a nominal altitude of 46 meters (150 feet) with a line spacing of 76 meters (250 feet). A contour map of the terrestrial gamma exposure rate extrapolated to 1 meter above ground level was prepared and overlaid on a set of United States Geological Survey topographic maps of the area and an aerial photograph of the plant. The terrestrial gamma exposure rates varied from about 7 to 14 microroentgens per hour at 1 meter above the ground. Protactinium-234m was observed at six sites within the boundaries of the plant. At a seventh site, only uranium-235 was observed. No other man-made, gamma ray-emitting radioactive material was present in a detectable quantity, either on or off the plant property. Soil sample and pressurized ion chamber measurements were obtained at four locations within the survey boundaries to support the aerial data. The results of the aerial and ground-based measurements were found to agree within ± 7.5%

Report on the biological monitoring program at Paducah Gaseous Diffusion Plant, January--December 1996

Energy Technology Data Exchange (ETDEWEB)

Kszos, L.A. [ed.; Konetsky, B.K.; Peterson, M.J.; Petrie, R.B.; Ryon, M.G.; Smith, J.G.; Southworth, G.R.

1997-06-01

On September 24, 1987, the Commonwealth of Kentucky Natural Resources and Environmental Protection Cabinet issued an Agreed Order that required the development of a Biological Monitoring Program (BMP) for the Paducah Gaseous diffusion Plant (PGDP). The PGDP BMP was conducted by the University of Kentucky Between 1987 and 1992 and by staff of the Environmental Sciences Division (ESD) at Oak Ridge National Laboratory (ORNL) from 1991 to present. The goals of BMP are to (1) demonstrate that the effluent limitations established for PGDP protect and maintain the use of Little Bayou and Big Bayou creeks for growth and propagation of fish and other aquatic life, (2) characterize potential environmental impacts, and (3) document the effects of pollution abatement facilities on stream. The BMP for PGDP consists of three major tasks: (1) effluent toxicity monitoring, (2) bioaccumulation studies, and (3) ecological surveys of stream communities (i.e., benthic macroinvertebrates and fish). This report focuses on ESD activities occurring from January 1996 to December 1996, although activities conducted outside this time period are included as appropriate.

Report on the biological monitoring program at Paducah Gaseous Diffusion Plant, January - December 1996

International Nuclear Information System (INIS)

Kszos, L.A.; Konetsky, B.K.; Peterson, M.J.; Petrie, R.B.; Ryon, M.G.; Smith, J.G.; Southworth, G.R.

1997-06-01

On September 24, 1987, the Commonwealth of Kentucky Natural Resources and Environmental Protection Cabinet issued an Agreed Order that required the development of a Biological Monitoring Program (BMP) for the Paducah Gaseous diffusion Plant (PGDP). The PGDP BMP was conducted by the University of Kentucky Between 1987 and 1992 and by staff of the Environmental Sciences Division (ESD) at Oak Ridge National Laboratory (ORNL) from 1991 to present. The goals of BMP are to (1) demonstrate that the effluent limitations established for PGDP protect and maintain the use of Little Bayou and Big Bayou creeks for growth and propagation of fish and other aquatic life, (2) characterize potential environmental impacts, and (3) document the effects of pollution abatement facilities on stream. The BMP for PGDP consists of three major tasks: (1) effluent toxicity monitoring, (2) bioaccumulation studies, and (3) ecological surveys of stream communities (i.e., benthic macroinvertebrates and fish). This report focuses on ESD activities occurring from January 1996 to December 1996, although activities conducted outside this time period are included as appropriate

Operational readiness review for the TSCA incinerator start-up at the Oak Ridge K-25 site

International Nuclear Information System (INIS)

Jordan, Elizabeth A.; Murray, Alexander P.; Kiang, Peter M.

1992-01-01

The Department of Energy (DOE) Toxic Substances Control Act (TSCA) incinerator at Oak Ridge K-25 Site was designed in the early 1980's as a treatment alternative for the increasing quantities of radioactive mixed waste accumulating from gaseous diffusion plant (GDP) operations. The waste feed principally contains low assay uranium and PCBs, although listed solvents and heavy metal containing sludges have also be incinerated. Construction was completed in 1986 and the unit underwent an extensive series of tests and trial burns, because of the following unique characteristics: the incinerator treats radioactive mixed wastes; increased size of the incinerator for greater waste throughout and treatment capacity; expansion of the waste acceptance criteria to include materials and radionuclides from non-GDP operations, such as ORNL and Y-12; modifications and improvement to the Air Pollution Control (APC) system; treatment of large quantities and concentrations of PCB containing materials; projected longevity of operation (40 years); humid, Eastern location with a high, annual precipitation. The incinerator was initially fired in July, 1986. The full performance testing (with the APC) and DOE acceptance of the facility occurred a year later. The trial burn period lasted from 1988 through 1990. Numerous equipment problems were initially encountered, including excessive draft fan wear and failure. These problems have been overcome, the facility is fully permitted, DOE provided authorization for full operations in 1991, and, to date, over two million pounds of mixed waste have been incinerated, with an average volume reduction factor of approximately nine. This paper discusses the Office of Environmental Restoration and Waste Management Readiness Review for the incinerator. (author)

Carbon isotope exchange between gaseous CO2 and thin solution films: Artificial cave experiments and a complete diffusion-reaction model

Science.gov (United States)

Hansen, Maximilian; Scholz, Denis; Froeschmann, Marie-Louise; Schöne, Bernd R.; Spötl, Christoph

2017-08-01

Speleothem stable carbon isotope (δ13C) records provide important paleoclimate and paleo-environmental information. However, the interpretation of these records in terms of past climate or environmental change remains challenging because of various processes affecting the δ13C signals. A process that has only been sparsely discussed so far is carbon isotope exchange between the gaseous CO2 of the cave atmosphere and the dissolved inorganic carbon (DIC) contained in the thin solution film on the speleothem, which may be particularly important for strongly ventilated caves. Here we present a novel, complete reaction diffusion model describing carbon isotope exchange between gaseous CO2 and the DIC in thin solution films. The model considers all parameters affecting carbon isotope exchange, such as diffusion into, out of and within the film, the chemical reactions occurring within the film as well as the dependence of diffusion and the reaction rates on isotopic mass and temperature. To verify the model, we conducted laboratory experiments under completely controlled, cave-analogue conditions at three different temperatures (10, 20, 30 °C). We exposed thin (≈0.1 mm) films of a NaHCO3 solution with four different concentrations (1, 2, 5 and 10 mmol/l, respectively) to a nitrogen atmosphere containing a specific amount of CO2 (1000 and 3000 ppmV). The experimentally observed temporal evolution of the pH and δ13C values of the DIC is in good agreement with the model predictions. The carbon isotope exchange times in our experiments range from ca. 200 to ca. 16,000 s and strongly depend on temperature, film thickness, atmospheric pCO2 and the concentration of DIC. For low pCO2 (between 500 and 1000 ppmV, as for strongly ventilated caves), our time constants are substantially lower than those derived in a previous study, suggesting a potentially stronger influence of carbon isotope exchange on speleothem δ13C values. However, this process should only have an

The use of diffusive samplers for collecting organic gaseous constituents in waste gases. Diffusionssammler zur Probenahme von organischen gas- und dampffoermigen Substanzen in Abgasen

Energy Technology Data Exchange (ETDEWEB)

Canela, A.; Gruntz, U.; Muehleisen, H.; Tanner, S. (Sandoz AG, Basel (Switzerland). Umweltschutzlaboratorien)

1990-01-01

A relatively simple procedure for sample collection of multicomponent organic emissions is presented. A representative part of the waste gas is taken by means of a sampling probe and flows to the coupled sampling device. The gaseous constituents are collected in several diffusive samplers at the bottom of the device. Influencing parameters such as pressure, temperature, gas velocity etc., which may affect the collection rate and therefore the measured values, were investigated in the laboratory. Depending on the analytical detection limit, the sampling time and the diffusion parameters, the method can be applied for the determination of integrated emission concentrations between 0.1 mg/m{sup 3} and 1 g/m{sup 3}. (orig.).

Thermal diffusion (1963); Diffusion thermique (1963)

Energy Technology Data Exchange (ETDEWEB)

Lemarechal, A [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1963-07-01

This report brings together the essential principles of thermal diffusion in the liquid and gaseous phases. The macroscopic and molecular aspects of the thermal diffusion constant are reviewed, as well as the various measurement method; the most important developments however concern the operation of the CLUSIUS and DICKEL thermo-gravitational column and its applications. (author) [French] Ce rapport rassemble les principes essentiels de la diffusion thermique en phase liquide et en phase gazeuse. Les aspects macroscopique et moleculaire de la constante de diffusion thermique sont passes en revue ainsi que ses differentes methodes de mesure; mais les developpements les plus importants concernent le fonctionnement de ls colonne thermogravitationnelle de CLUSIUS et DICKEL et ses applications. (auteur)

The Mailbox Computer System for the IAEA verification experiment on HEU downblending at the Portsmouth Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Aronson, A.L.; Gordon, D.M.

2000-01-01

IN APRIL 1996, THE UNITED STATES (US) ADDED THE PORTSMOUTH GASEOUS DIFFUSION PLANT TO THE LIST OF FACILITIES ELIGIBLE FOR THE APPLICATION OF INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA) SAFEGUARDS. AT THAT TIME, THE US PROPOSED THAT THE IAEA CARRY OUT A ''VERIFICATION EXPERIMENT'' AT THE PLANT WITH RESPECT TO DOOWNBLENDING OF ABOUT 13 METRIC TONS OF HIGHLY ENRICHED URANIUM (HEU) IN THE FORM OF URANIUM HEXAFLUROIDE (UF6). DURING THE PERIOD DECEMBER 1997 THROUGH JULY 1998, THE IAEA CARRIED OUT THE REQUESTED VERIFICATION EXPERIMENT. THE VERIFICATION APPROACH USED FOR THIS EXPERIMENT INCLUDED, AMONG OTHER MEASURES, THE ENTRY OF PROCESS-OPERATIONAL DATA BY THE FACILITY OPERATOR ON A NEAR-REAL-TIME BASIS INTO A ''MAILBOX'' COMPUTER LOCATED WITHIN A TAMPER-INDICATING ENCLOSURE SEALED BY THE IAEA

The Martin Marietta Energy Systems personnel neutron dosimetry program

International Nuclear Information System (INIS)

McMahan, K.L.

1991-01-01

Martin Marietta Energy Systems, Inc. (Energy Systems), manages five sites for the US Department of Energy. Personnel dosimetry for four of the five sites is coordinated through a Centralized External Dosimetry System (CEDS). These four sites are the Oak Ridge National Laboratory (ORNL), the Oak Ridge Y-12 Plant (Y-12), the Oak Ridge K-25 Site (K-25), and the Paducah Gaseous Diffusion Plant (PGDP). The fifth Energy Systems site, Portsmouth Gaseous Diffusion Plant, has an independent personnel dosimetry program. The current CEDS personnel neutron dosimeter was first issued in January 1989, after an evaluation and characterization of the dosimeters' response in the workplaces was performed. For the workplace characterization, Energy Systems contracted with Pacific Northwest Laboratory (PNL) to perform neutron measurements at selected locations at ORNL and Y-12. K-25 and PGDP were not included because their neutron radiation fields were similar to others already planned for characterization at ORNL and Y-12. Since the initial characterization, PNL has returned to Oak Ridge twice to perform follow up measurements, and another visit is planned in the near future

Method of separating tritium contained in gaseous wastes

International Nuclear Information System (INIS)

Hashimoto, Yasuo; Oozono, Hideaki.

1981-01-01

Purpose: To decrease tritium concentration in gaseous wastes to less than the allowable level by removing tritium in gaseous wastes generated upon combustion of radioactive wastes by using a plurality of heat exchangers. Method: Gaseous wastes at high temperature generated upon combustion of radioactive wastes in an incinerator are removed with radioactive solid substances through filters, cooled down to a temperature below 10 0 C by the passage through first and second heat exchangers and decreased with tritium content to less than the allowable concentration by the gaseous wastes at low temperature from the second heat exhcanger. The gaseous wastes at low temperature are used as the cooling medium for the first heat exchanger. They are heat exchanged at the upstream of the second heat exchanger with the cooling water from the third heat exchanger and cooled at the downstream by the cooling water cooled by the cooling medium. The gaseous wastes at low temperature thus cooled below 10 0 C are heated to about 350 0 C in the first heat exchanger and discharged. (Moriyama, K.)

Thermal diffusion (1963)

International Nuclear Information System (INIS)

Lemarechal, A.

1963-01-01

This report brings together the essential principles of thermal diffusion in the liquid and gaseous phases. The macroscopic and molecular aspects of the thermal diffusion constant are reviewed, as well as the various measurement method; the most important developments however concern the operation of the CLUSIUS and DICKEL thermo-gravitational column and its applications. (author) [fr

Oxygen diffusion through soil covers on sulphidic mine tailings

International Nuclear Information System (INIS)

Yanful, E.K.

1993-01-01

Engineered soil covers are being evaluated under Canada's Mine Environment Neutral Drainage (MEND) program for their effectiveness in preventing and controlling acid generation in sulfidic mill tailings. A critical parameter for predicting the performance of these covers is the diffusion coefficient of gaseous oxygen in the cover materials. Laboratory experiments conducted to determine the effective diffusion coefficient of a candidate cover material, a glacial till from an active mine site, are described. The diffusion coefficient is determined by fitting a semianalytic solution of the one-dimensional, transient diffusion equation to experimental gaseous oxygen concentration versus time graphs. Effective diffusion coefficients determined at high water saturations (85%--95%) were of the order of 8 x 10 -8 m 2 /s. The diffusion coefficients decreased with increase in water saturation as a result of the low diffusivity of gaseous oxygen in water relative to that in air and the low solubility of oxygen in water. Placement of soil covers in high saturation conditions would ensure that the flux of oxygen into tailings underneath such covers is low, resulting in low acid flux. This is confirmed by combined laboratory, field, and modeling studies

Process control of a gaseous diffusion cascade for isotopic separation of uranium

International Nuclear Information System (INIS)

Bilous, Olegh; Doneddu, F.

1986-01-01

Various aspects of dynamics and process control of a gaseous diffusion cascade are described. The cascade enriches uranium hexafluoride gas (HEX) in the light isotope of uranium in a countercurrent flow. The linearized equations describing the equipment models are derived. One can then write the mass balances on the high and low pressure sides of a stage and the overall heat balance of a stage. These heat and mass balances are linear difference equations on the stage number with time derivatives which are then replaced by jω factors to examine the effects of cyclic perturbations. The mass balances are first treated for a cascade section of 12 stages with temperatures assumed constant. The effect of a perturbation of pressure on one of the stages is described first for ω=0 (that is for steady state). Then Nyquist diagrams are obtained. The effect of transport change is also studied. Then temperature is introduced, assuming pressures to be constant. The cases of a section of 12 stages and a cascade of 120 stages are examined. Again Nyquist diagrams of temperature frequency response to a perturbation on one stage are calculated. Process control of the heat exchangers is introduced. The method used to solve the difference equations may be applied to other types of perturbations and to the complete scheme of process control. (author)

Deuterium diffusion along the three principal directions in anisotropic Zr–2.5Nb

Energy Technology Data Exchange (ETDEWEB)

Khatamian, D., E-mail: khatamiand@aecl.ca

2013-12-15

Highlights: •Diffusivity of deuterium in a Zr–2.5Nb plate was measured. •The plate had similar microstructure to that of a CANDU pressure tube. •Diffusion coefficients in the radial direction were 24% less than in the longitudinal direction. •These findings are in close agreement with the theoretical estimates made in the literature. -- Abstract: Pressure tubes of cold-worked Zr–2.5Nb material are used in the CANDU (CANada Deuterium Uranium is a registered trademark of Atomic Energy of Canada Ltd.) reactors to contain the fuel bundles and the heavy water coolant. The pressure tube microstructure consists of α-Zr platelets, with an aspect ratio of 1:5:50 in the radial, transverse and longitudinal directions, surrounded by a thin layer of β-Zr. The diffusivity of hydrogen in β-Zr is higher than in α-Zr. As a result, the diffusivity of hydrogen in the pressure tube material is enhanced compared to unalloyed α-Zr. Due to the anisotropic microstructure of the pressure tube with respect to the β-Zr network, the diffusivity of hydrogen is thought to be different in the three principal pressure tube directions. Measurements made using specimens machined from an 8 mm thick Zr–2.5Nb plate, with a microstructure similar to that of a CANDU pressure tube, suggest the difference between the diffusion constants for deuterium in different directions of an as-installed pressure tube may be as high as 25%.

Study of the $K^{+}K^{-} \\pi^{+}\\pi^{-}\\pi^{0}$ final state in antiproton annihilation at rest in gaseous hydrogen at NTP with the OBELIX spectrometer

CERN Document Server

Nichitiu, F; Balestra, F; Bertin, A; Bonomi, G; Botta, E; Bressani, Tullio; Bruschi, M; Bussa, M P; Busso, L; Calvo, D; Capponi, M; Cerello, P G; Cicalò, C; Costa, S; D'Isep, D; De Castro, S; De Galco, A; Denisov, O; Donzella, A; Feliciello, A; Filippi, A; Filippini, V; Fontana, A; Galli, D; Garfagnini, R; Giacobbe, B; Gianotti, P; Gorchakov, O E; Grasso, A; Guaraldo, C; Iazzi, F; Lanaro, A; Lodi-Rizzini, E; Lucherini, V; Maggiora, A; Marcello, S; Marconi, U; Masoni, A; Massa, I; Mauro, S; Minetti, B; Mirfakhraee, N; Montagna, P; Panzarasa, A; Panzieri, D; Petrascu, C; Piccinini, M; Poli, M; Prakhov, S N; Puddu, G; Rosca, A; Rotondi, A; Rozhdestvensky, A M; Salvini, P; Semprini-Cesari, N; Spighi, R; Tessaro, S; Tosello, F; Tretyak, V I; Usai, G L; Vagnoni, V M; Vecchi, S; Venturelli, L; Villa, M; Vitale, A; Zenoni, A; Zoccoli, A

2002-01-01

A spin-parity analysis of a sample of pp to K/sup +/K/sup -/ pi /sup +/ pi /sup -/ pi /sup 0/ annihilation events taken at rest in gaseous H/sub 2/ at NTP is reported. The invariant mass spectrum of the K/sup +/K/sup -/ pi /sup 0/ system shows the presence of the E/t resonance pattern at 1.42 GeV. The analysis of this signal confirms the results obtained by the OBELIX Collaboration in previous works, namely: the existence of two pseudoscalar states at 1.413+or-0.002 and 1.460+or-0.012 GeV with widths 0.051+or-0.004 and 0.120+or-0.015 GeV, respectively. The pp system in the /sup 3/P/sub 1/ wave shows also a signal corresponding to the axial vector f/sub 1/ (1420) decaying to K*K with mass 1.420+or-0.003 GeV and width 0.061+or-0.005 GeV. A study of the incoherent phase space background shows that its origin is mostly due to the reflection of a resonant state in the K/sup +/K /sup -/ pi /sup +/ pi /sup -/ system. The isobar decomposition of this resonant state is mainly f/sub 0/(1370)( pi pi )/sub S/, its parame...

Review of microfluidic cell culture devices for the control of gaseous microenvironments in vitro

Science.gov (United States)

Wu, H.-M.; Lee, T.-A.; Ko, P.-L.; Chiang, H.-J.; Peng, C.-C.; Tung, Y.-C.

2018-04-01

Gaseous microenvironments play important roles in various biological activities in vivo. However, it is challenging to precisely control gaseous microenvironments in vitro for cell culture due to the high diffusivity nature of gases. In recent years, microfluidics has paved the way for the development of new types of cell culture devices capable of manipulating cellular microenvironments, and provides a powerful tool for in vitro cell studies. This paper reviews recent developments of microfluidic cell culture devices for the control of gaseous microenvironments, and discusses the advantages and limitations of current devices. We conclude with suggestions for the future development of microfluidic cell culture devices for the control of gaseous microenvironments.

20 kHz, 25 kVA node power transformer

Science.gov (United States)

Hussey, S.

1989-01-01

The electrical and mechanical design information and the electrical and thermal testing performed on the 440-208-V rms, 20-kHz, 25-kVa prototype node transformer are summarized. The calculated efficiency of the node transformer is 99.3 percent based on core loss and copper loss test data, and its maximum calculated load regulation is 0.7 percent. The node transformer has a weight of 19.7 lb and has a power density of 0.8 lb/kW. The hot-spot temperature rise is estimated to be 33 C above the cold plate mounting base. This proof-of-concept transformer design is a viable candidate for the space station Freedom application.

Environmental Management Waste Management Facility Proxy Waste Lot Profile 6.999 for Building K-25 West Wing, East Tennessee Technology Park, Oak Ridge, Tennessee

Energy Technology Data Exchange (ETDEWEB)

Rigsby V.P.

2009-02-12

In 1989, the Oak Ridge Reservation (ORR), which includes the East Tennessee Technology Park (ETTP), was placed on the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA) National Priorities List. The Federal Facility Agreement (FFA) (DOE 1992), effective January 1, 1992, now governs environmental restoration activities conducted under CERCLA at the ORR. Following signing of the FFA, U.S. Department of Energy (DOE), U.S. Environmental Protection Agency (EPA), and the state of Tennessee signed the Oak Ridge Accelerated Cleanup Plan Agreement on June 18, 2002. The purpose of this agreement is to define a streamlined decision-making process to facilitate the accelerated implementation of cleanup, resolve ORR milestone issues, and establish future actions necessary to complete the accelerated cleanup plan by the end of fiscal year 2008. While the FFA continues to serve as the overall regulatory framework for remediation, the Accelerated Cleanup Plan Agreement supplements existing requirements to streamline the decision-making process. Decontamination and decommissioning (D&D) activities of Bldg. K-25, the original gaseous diffusion facility, is being conducted by Bechtel Jacobs Company LLC (BJC) on behalf of the DOE. The planned CERCLA action covering disposal of building structure and remaining components from the K-25 building is scheduled as a non-time-critical CERCLA action as part of DOE's continuous risk reduction strategy for ETTP. The K-25 building is proposed for D&D because of its poor physical condition and the expense of surveillance and maintenance activities. The K-25/K-27 D&D Project proposes to dispose of the commingled waste listed below from the K-25 west side building structure and remaining components and process gas equipment and piping at the Environmental Management Waste Management Facility (EMWMF) under waste disposal proxy lot (WPXL) 6.999: (1) Building structure (e.g. concrete floors [excluding basement

Report on the biological monitoring program at Paducah Gaseous Diffusion Plant December 1990 to November 1992

Energy Technology Data Exchange (ETDEWEB)

Kszos, L.A. [ed.

1994-03-01

On September 23, 1987, the Commonwealth of Kentucky Natural Resources and Environmental Protection Cabinet issued an Agreed Order that required the development of a Biological Monitoring Program (BMP) for the Paducah Gaseous Diffusion Plant (PGDP). Beginning in fall 1991, the Environmental Sciences Division (ESD) at Oak Ridge National Lab (ORNL) added data collection and report preparation to its responsibilities for the PGDP BMP. The BMP has been continued because it has proven to be extremely valuable in identifying those effluents with the potential for adversely affecting instream fauna, assessing the ecological health of receiving streams, guiding plans for remediation, and protecting human health. In September 1992, a renewed permit was issued which requires toxicity monitoring of continuous and intermittent outfalls on a quarterly basis. The BMP for PGDP consists of three major tasks: (1) effluent and ambient toxicity monitoring, (2) bioaccumulation studies, and (3) ecological surveys of stream communities. This report includes ESD/ORNL activities occurring from December 1990 to November 1992.

Report on the biological monitoring program at Paducah Gaseous Diffusion Plant December 1990 to November 1992

International Nuclear Information System (INIS)

Kszos, L.A.

1994-03-01

On September 23, 1987, the Commonwealth of Kentucky Natural Resources and Environmental Protection Cabinet issued an Agreed Order that required the development of a Biological Monitoring Program (BMP) for the Paducah Gaseous Diffusion Plant (PGDP). Beginning in fall 1991, the Environmental Sciences Division (ESD) at Oak Ridge National Lab (ORNL) added data collection and report preparation to its responsibilities for the PGDP BMP. The BMP has been continued because it has proven to be extremely valuable in identifying those effluents with the potential for adversely affecting instream fauna, assessing the ecological health of receiving streams, guiding plans for remediation, and protecting human health. In September 1992, a renewed permit was issued which requires toxicity monitoring of continuous and intermittent outfalls on a quarterly basis. The BMP for PGDP consists of three major tasks: (1) effluent and ambient toxicity monitoring, (2) bioaccumulation studies, and (3) ecological surveys of stream communities. This report includes ESD/ORNL activities occurring from December 1990 to November 1992

Thermochemical study of 2,5-dimethyl-3-furancarboxylic acid, 4,5-dimethyl-2-furaldehyde, and 3-acetyl-2,5-dimethylfuran

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Amaral, Luisa M.P.F.

2011-01-01

The standard (p o = 0.1 MPa) molar enthalpies of formation, in the gaseous state, at T = 298.15 K, for 2,5-dimethyl-3-furancarboxylic acid, 3-acetyl-2,5-dimethylfuran, and 4,5-dimethyl-2-furaldehyde were derived from the values of the standard molar enthalpies of formation, in the condensed phase, and the standard molar enthalpies of phase transition from the condensed to the gaseous state. The values of the standard molar enthalpies of formation of the compounds in the condensed phases were calculated from the measurements of the standard massic energies of combustion obtained by static bomb combustion calorimetry. The enthalpies of vaporization/sublimation were measured by Calvet high temperature microcalorimetry. For 2,5-dimethyl-3-furancarboxylic acid the standard enthalpy of sublimation was also calculated, by the application of the Clausius-Clapeyron equation, to the temperature dependence of the vapor pressures measured by the Knudsen effusion technique. (table)

78 FR 65389 - United States Enrichment Corporation, Paducah Gaseous Diffusion Plant

Science.gov (United States)

2013-10-31

..., USEC notified the NRC of its decision to permanently cease uranium enrichment activities at the PGDP... Accession Nos. ML13105A010 and ML13176A151, respectively. NRC's PDR: You may examine and purchase copies of... in Paducah, Kentucky, using the gaseous [[Page 65390

Oak Ridge K-25 Site Technology Logic Diagram

Energy Technology Data Exchange (ETDEWEB)

Fellows, R.L. (ed.)

1993-02-26

The Oak Ridge K-25 Technology Logic Diagram (TLD), a decision support tool for the K-25 Site, was developed to provide a planning document that relates envirorunental restoration and waste management problems at the Oak Ridge K-25 Site to potential technologies that can remediate these problems. The TLD technique identifies the research necessary to develop these technologies to a state that allows for technology transfer and application to waste management, remedial action, and decontamination and decommissioning activities. The TLD consists of four separate volumes-Vol. 1, Vol. 2, Vol. 3A, and Vol. 3B. Volume 1 provides introductory and overview information about the TLD. This volume, Volume 2, contains logic diagrams with an index. Volume 3 has been divided into two separate volumes to facilitate handling and use.

Graphic displays on PCs of gaseous diffusion models of radionuclide releases to the atmosphere

International Nuclear Information System (INIS)

Campo Ortega, E. del

1993-01-01

The well-known MESOI program has been modified and improved to adapt it to a PC/AT with VGA colour monitor. Far from losing any of its powerful characteristics to calculate the transport, diffusion, deposition and decay of gaseous radioactive effluents discharged to the atmosphere, it has been enhanced to allow graphic viewing of concentrations, wind speed and direction and puff locations in colour, all on a background map of the site. The background covers a 75 x 75 km square and has a graphic grid density of 421 x 421 pixels. This means that effluent concentration is represented approximately every 170 metres in the 'clouded-area'. Among the modifications and enhancements made, the following are of particular interest: 1. A new subroutine called NUBE has been added, which calculates the distribution of effluent concentration of activity in a grid of 421 x 421 pixels. 2. Several subroutines have been added to obtain graphic displays and printouts of the cloud, wind field and puff locations. 3. Graphic display of the geographic plane of the area surrounding the effluent release point. 4. Off-line preparation of meteorological and topographical data files necessary for program execution. (author)

Report on the biological monitoring program at Paducah Gaseous Diffusion Plant, January--December 1997

Energy Technology Data Exchange (ETDEWEB)

Kszos, L.A.; Peterson, M.J.; Ryon, M.G.; Smith, J.G.; Southworth, G.R.

1998-03-01

On September 24, 1987, the Commonwealth of Kentucky Natural Resources and Environmental Protection Cabinet issued an Agreed Order that required the development of a Biological Monitoring Program (BMP) for the Paducah Gaseous Diffusion Plant (PGDP). A plan for the biological monitoring of the receiving streams was implemented in 1987 and consisted of ecological surveys, toxicity monitoring of effluents and receiving streams, evaluation of bioaccumulation of trace contaminants in biota, and supplemental chemical characterization of effluents. Beginning in fall 1991, the Environmental Sciences Division (ESD) at Oak Ridge National Laboratory added data collection and report preparation to its responsibilities for the PGDP BMP. The BMP has been continued because it has proven to be extremely valuable in (1) identifying those effluents with the potential for adversely affecting instream fauna, (2) assessing the ecological health of receiving streams, and (3) guiding plans for remediation and protecting human health. The BMP for PGDP consists of three major tasks: (1) effluent toxicity monitoring, (2) bioaccumulation studies, and (3) ecological surveys of benthic macroinvertebrate communities and fish. With the exception of the benthic macroinvertebrate community surveys, this report focuses on activities from January to December 1997.

Operating limit study for the proposed solid waste landfill at Paducah Gaseous Diffusion Plant

Energy Technology Data Exchange (ETDEWEB)

Lee, D.W.; Wang, J.C.; Kocher, D.C.

1995-06-01

A proposed solid waste landfill at Paducah Gaseous Diffusion Plant (PGDP) would accept wastes generated during normal operations that are identified as non-radioactive. These wastes may include small amounts of radioactive material from incidental contamination during plant operations. A site-specific analysis of the new solid waste landfill is presented to determine a proposed operating limit that will allow for waste disposal operations to occur such that protection of public health and the environment from the presence of incidentally contaminated waste materials can be assured. Performance objectives for disposal were defined from existing regulatory guidance to establish reasonable dose limits for protection of public health and the environment. Waste concentration limits were determined consistent with these performance objectives for the protection of off-site individuals and inadvertent intruders who might be directly exposed to disposed wastes. Exposures of off-site individuals were estimated using a conservative, site-specific model of the groundwater transport of contamination from the wastes. Direct intrusion was analyzed using an agricultural homesteader scenario. The most limiting concentrations from direct intrusion or groundwater transport were used to establish the concentration limits for radionuclides likely to be present in PGDP wastes.

Report on the biological monitoring program at Paducah Gaseous Diffusion Plant, January-December 1997

International Nuclear Information System (INIS)

Kszos, L.A.; Peterson, M.J.; Ryon, M.G.; Smith, J.G.; Southworth, G.R.

1998-03-01

On September 24, 1987, the Commonwealth of Kentucky Natural Resources and Environmental Protection Cabinet issued an Agreed Order that required the development of a Biological Monitoring Program (BMP) for the Paducah Gaseous Diffusion Plant (PGDP). A plan for the biological monitoring of the receiving streams was implemented in 1987 and consisted of ecological surveys, toxicity monitoring of effluents and receiving streams, evaluation of bioaccumulation of trace contaminants in biota, and supplemental chemical characterization of effluents. Beginning in fall 1991, the Environmental Sciences Division (ESD) at Oak Ridge National Laboratory added data collection and report preparation to its responsibilities for the PGDP BMP. The BMP has been continued because it has proven to be extremely valuable in (1) identifying those effluents with the potential for adversely affecting instream fauna, (2) assessing the ecological health of receiving streams, and (3) guiding plans for remediation and protecting human health. The BMP for PGDP consists of three major tasks: (1) effluent toxicity monitoring, (2) bioaccumulation studies, and (3) ecological surveys of benthic macroinvertebrate communities and fish. With the exception of the benthic macroinvertebrate community surveys, this report focuses on activities from January to December 1997

Operating limit study for the proposed solid waste landfill at Paducah Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Lee, D.W.; Wang, J.C.; Kocher, D.C.

1995-06-01

A proposed solid waste landfill at Paducah Gaseous Diffusion Plant (PGDP) would accept wastes generated during normal operations that are identified as non-radioactive. These wastes may include small amounts of radioactive material from incidental contamination during plant operations. A site-specific analysis of the new solid waste landfill is presented to determine a proposed operating limit that will allow for waste disposal operations to occur such that protection of public health and the environment from the presence of incidentally contaminated waste materials can be assured. Performance objectives for disposal were defined from existing regulatory guidance to establish reasonable dose limits for protection of public health and the environment. Waste concentration limits were determined consistent with these performance objectives for the protection of off-site individuals and inadvertent intruders who might be directly exposed to disposed wastes. Exposures of off-site individuals were estimated using a conservative, site-specific model of the groundwater transport of contamination from the wastes. Direct intrusion was analyzed using an agricultural homesteader scenario. The most limiting concentrations from direct intrusion or groundwater transport were used to establish the concentration limits for radionuclides likely to be present in PGDP wastes

Application of a Kalman filter to UF6 gaseous diffusion plant freezer/sublimer systems

International Nuclear Information System (INIS)

Ruppel, F.R.

1992-03-01

A signal is required to control the flow of UF 6 in gaseous diffusion plant freezer/sublimer systems. The original strategy envisioned for deriving a flow signal was to take the derivative of the freezer/sublimer weigh cell signal. However, the derivative of the digitized weight signal is noisy, preventing good control. In addition, a bias is introduced into the weight derivative signal because a refrigerant is circulated through a shell-and-tube heat exchanger inside the freezer/sublimer. The weight of the refrigerant is included in the weight measured by the weigh cell. If the circulation rate of the refrigerent is not steady state, a bias exists. Measurements of upstream pressure, vessel pressure, and output to the system control valve are available to the control system. Thus, if the flow through the control valve is characterized properly by the measurements, a Kalman filter can be used in conjunction with these auxiliary inputs and the weigh cell input to overcome the noise and bias problem and provide an improve estimate of flow rate. A discussion of the development and the current status of a Kalman filter used for this application is given. 5 refs

Apparatus for diffusion separation

International Nuclear Information System (INIS)

Nierenberg, W.A.; Pontius, R.B.

1976-01-01

The method of testing the separation efficiency of porous permeable membranes is described which comprises causing a stream of a gaseous mixture to flow into contact with one face of a finely porous permeable membrane under such conditions that a major fraction of the mixture diffuses through the membrane, maintaining a rectangular cross section of the gaseous stream so flowing past said membrane, continuously recirculating the gas that diffuses through said membrane and continuously withdrawing the gas that does not diffuse through said membrane and maintaining the volume of said recirculating gas constant by continuously introducing into said continuously recirculating gas stream a mass of gas equivalent to that which is continuously withdrawn from said gas stream and comparing the concentrations of the light component in the entering gas, the withdrawn gas and the recirculated gas in order to determine the efficiency of said membrane

A cryostatic setup for the low-temperature measurement of thermal diffusivity with the photothermal method

International Nuclear Information System (INIS)

Bertolotti, M.; Liakhou, G.; Li Voti, R.; Paoloni, S.; Sibilia, C.; Sparvieri, N.

1995-01-01

A cryostatic setup is described to perform photothermal deflection measurements from room temperature to 77 K. The setup uses gaseous nitrogen as a medium where the photodeflection is produced. The ability of the system to work is demonstrated presenting some measurements of thermal diffusivity of high-temperature superconductor samples and of yttrium-iron garnets with variable aluminum content. copyright 1995 American Institute of Physics

Oak Ridge K-25 Site Technology Logic Diagram

Energy Technology Data Exchange (ETDEWEB)

Fellows, R.L. (ed.)

1993-02-26

The Oak Ridge K-25 Technology Logic Diagram (TLD), a decision support tool for the K-25 Site, was developed to provide a planning document that relates environmental restoration and waste management problems at the Oak Ridge K-25 Site to potential technologies that can remediate these problems. The TLD technique identifies the research necessary to develop these technologies to a state that allows for technology transfer and application to waste management, remedial action, and decontamination and decommissioning activities. The TLD consists of four separate volumes-Vol. 1, Vol. 2, Vol. 3A, and Vol. 3B. This Volume, Volume 1 provides introductory and overview information about the TLD. Volume 2 contains logic diagrams. Volume 3 has been divided into two separate volumes to facilitate handling and use. This volume is divided into ten chapters. The first chapter is a brief introduction, and the second chapter details the technical approach of the TLD. These categories are the work activities necessary for successful decontamination and decommissioning, waste management, and remedial action of the K-25 Site. The categories are characterization, decontamination, dismantlement, robotics and automation, remedial action, and waste management. Materials disposition is addressed in Chap. 9. The final chapter contains regulatory compliance information concerning waste management, remedial action, and decontamination and decommissioning.

Oak Ridge K-25 Site Technology Logic Diagram

Energy Technology Data Exchange (ETDEWEB)

Fellows, R.L. (ed.)

1993-02-26

The Oak Ridge K-25 Technology Logic Diagram (TLD), a decision support tool for the K-25 Site, was developed to provide a planning document that relates environmental restoration and waste management problems at the Oak Ridge K-25 Site to potential technologies that can remediate these problems. The TLD technique identifies the research necessary to develop these technologies to a state that allows for technology transfer and application to waste management, remedial action, and decontamination and decommissioning activities. The TLD consists of four separate volumes-Vol. 1, Vol. 2, Vol. 3A, and Vol. 3B. Volume 1 provides introductory and overview information about the TLD. Volume 2 contains logic diagrams. Volume 3 has been divided into two separate volumes to facilitate handling and use. This report is part A of Volume 3 concerning characterization, decontamination, and dismantlement.

Effect of potassium chloride on diffusion of theophylline at T = 298.15 K

Energy Technology Data Exchange (ETDEWEB)

Santos, Cecilia I.A.V., E-mail: cecilia.alves@uah.e [Departamento de Quimica Fisica, Facultad de Farmacia, Universidad de Alcala, 28871 Alcala de Henares, Madrid (Spain); Lobo, Victor M.M., E-mail: vlobo@ci.uc.p [Department of Chemistry, University of Coimbra, 3004-535 Coimbra (Portugal); Esteso, Miguel A., E-mail: miguel.esteso@uah.e [Departamento de Quimica Fisica, Facultad de Farmacia, Universidad de Alcala, 28871 Alcala de Henares, Madrid (Spain); Ribeiro, Ana C.F., E-mail: anacfrib@ci.uc.p [Department of Chemistry, University of Coimbra, 3004-535 Coimbra (Portugal)

2011-06-15

Research highlights: {yields} Mutual diffusion coefficients of theophylline in aqueous dilute solutions. {yields} Influence of the presence of potassium chloride in the aqueous media. {yields} Estimation of the association constant, K, between THP and KCl. - Abstract: Ternary mutual diffusion coefficients measured by Taylor dispersion method (D{sub 11}, D{sub 22}, D{sub 12}, and D{sub 21}) are reported for aqueous solutions of KCl + theophylline (THP) at T = 298.15 K at carrier concentrations from (0.000 to 0.010) mol {center_dot} dm{sup -3}, for each solute. These diffusion coefficients have been measured having in mind a better understanding of the structure of these systems and the thermodynamic behavior of potassium chloride and theophylline in solution. For example, from these data it will be possible to make conclusions about the influence of this electrolyte in diffusion of THP and to estimate some parameters, such as the diffusion coefficient of the aggregate between KCl and THP.

Long-term mortality study of workers occupationally exposed to metallic nickel at the Oak Ridge Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Godbold, J.H. Jr.; Tompkins, E.A.

1979-01-01

This study was undertaken to determine whether mortality from respiratory cancer among workers occupationally exposed to metallic nickel at the Oak Ridge Gaseous Diffusion Plant (ORGDP) differed from that of workers at the same plant with no record of occupational exposure to metallic nickel or any nickel compound. A cohort of 814 nickel-exposed workers and one of 1600' controls were identified. The members of both cohorts had a minimum follow-up period of 19 years. Mortality from respiratory cancer and from other causes was examined in both groups. The data showed no evidence of an increased risk of mortality due to respiratory cancer among the nickel-exposed workers. The exposed cohort experienced lower mortality than the controls, both in deaths due to respiratory cancer and in deaths due to all causes, although neither of these differences was statistically significant

X-ray and neutron diffuse scattering in LiNbO3 from 38 to 1200 K

International Nuclear Information System (INIS)

Zotov, N.; Mayer, H.M.; Guethoff, F.; Hohlwein, D.

1995-01-01

A semi-quantitative description of X-ray and neutron diffuse scattering from congruent lithium niobate, LiNbO 3 , is given. The diffuse scattering is concentrated in three sets of diffuse planes perpendicular to the pseudo-cubic symmetry-related [221], [241] and [ anti 4 anti 21] directions and can be attributed to one-dimensional displacive and chemical disorder along these directions. The variation of the X-ray and neutron diffuse intensities with the scattering vector, as well as the comparison between X-ray and neutron data, indicate that more than one type of atom is involved. Temperature variations are followed from 38 to 1200 K. Different disorder models are discussed. The increase of the integrated intensities of the diffuse lines along the [0 1k 2l] * and [0 anti 1k 4l] * directions (i.e. sections of the diffuse planes) up to 800 K followed by a slight decrease at higher temperatures may be interpreted either by static disorder related to temperature-dependent variation of disorder/defect clusters or by dynamic disorder. Inelastic neutron scattering experiments do not show any anomaly of the transversal acoustic (TA) modes. (orig.)

Cooling tower drift studies at the Paducah, Kentucky Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Taylor, F.G.; Hanna, S.R.; Parr, P.D.

1979-01-01

The transfer and fate of chromium from cooling tower drift to terrestrial ecosystems were quantified at the Department of Energy's uranium enrichment facility at Paducah, Kentucky. Chromium concentrations in plant materials (fescue grass) decreased with increasing distance from the cooing tower, ranging from 251 +- 19 ppM at 15 meters to 0.52 +- 0.07 ppM at 1500 meters. The site of drift contamination, size characteristics, and elemental content of drift particles were determined using a scanning electron microscope with energy dispersive x-ray analysis capabilities. Results indicate that elemental content in drift water (mineral residue) may not be equivalent to the content in the recirculating cooling water of the tower. This hypothesis is contrary to basic assumptions in calculating drift emissions. A laboratory study simulating throughfall from 1 to 6 inches of rain suggested that there are more exchange sites associated with litter than live foliage. Leachate from each one inch throughfall simulant removed 3% of the drift mass from litter compared to 7 to 9% from live foliage. Results suggest that differences in retention are related to chemical properties of the drift rather than physical lodging of the particle residue. To determine the potential for movement of drift-derived chromium to surface streams, soil--water samplers (wells) were placed along a distance gradient to Little Bayou Creek. Samples from two depths following rainstorms revealed the absence of vertical or horizontal movement with maximum concentrations of 0.13 ppb at 50 meters from the tower. Preliminary model estimates of drift deposition are compared to depositionmeasurements. Isopleths of the predicted deposition are useful to identify areas of maximum drift transport in the environs of the gaseous diffusion plant

Diffusion coefficients of nickel chloride in aqueous solutions of lactose at T = 298.15 K and T = 310.15 K

International Nuclear Information System (INIS)

Ribeiro, Ana C.F.; Gomes, Joselaine C.S.; Barros, Marisa C.F.; Lobo, Victor M.M.; Esteso, Miguel A.

2011-01-01

Binary mutual diffusion coefficients (interdiffusion coefficients) of nickel chloride in water at T = 298.15 K and T = 310.15 K, and at concentrations between (0.000 and 0.100) mol · dm -3 , using a Taylor dispersion method have been measured. These data are discussed on the basis of the Onsager-Fuoss and Pikal models. The equivalent conductance at infinitesimal concentration of the nickel ion in these solutions at T = 310.15 K has been estimated using these results. Through the same technique, ternary mutual diffusion coefficients (D 11 , D 22 , D 12 , and D 21 ) for aqueous solutions containing NiCl 2 and lactose, at T = 298.15 K and T = 310.15 K, and at different carrier concentrations were also measured. These data permit us to have a better understanding of the structure of these systems and the thermodynamic behaviour of NiCl 2 in different media.

Computational fluid dynamics tracking of UF6 reaction products release into a gaseous diffusion plant cell housing

International Nuclear Information System (INIS)

Wendel, M.W.; Chen, N.C.J.; Kim, S.H.; Taleyarkhan, R.P.; Keith, K.D.; Schmidt, R.W.

1996-01-01

A three-dimensional (3-D) computational fluid dynamics (CFD) model has been developed using CFDS-FLOW3D Version 3.3 to model the transport of aerosol products formed during a release of uranium hexafluoride (UF 6 ) into a gaseous diffusion plant (GDP) process building. As part of a facility-wide safety evaluation, a one-dimensional (1-D) analysis of aerosol/vapor transport following such an hypothesized severe accident is being performed. The objective of this study is to supplement the 1-D analysis with more detailed 3-D results. Specifically, the goal is to quantify the distribution of aerosol passing out of the process building during the hypothetical accident. This work demonstrates a useful role for CFD in large 3-D problems, where some experimental data are available for calibrating key parameters and the desired results are global (total time-integrated aerosol flow rates across a few boundary surfaces) as opposed to local velocities, temperatures, or heat transfer coefficients

Spatial distribution of radiation damage to crystalline proteins at 25–300 K

Energy Technology Data Exchange (ETDEWEB)

Warkentin, Matthew; Badeau, Ryan; Hopkins, Jesse B.; Thorne, Robert E., E-mail: ret6@cornell.edu [Cornell University, Ithaca, NY 14853 (United States)

2012-09-01

Dose-dependent atomic B factors are used to determine the average spatial distribution of radiation damage to crystalline thaumatin and urease. The spatial distribution of radiation damage (assayed by increases in atomic B factors) to thaumatin and urease crystals at temperatures ranging from 25 to 300 K is reported. The nature of the damage changes dramatically at approximately 180 K. Above this temperature the role of solvent diffusion is apparent in thaumatin crystals, as solvent-exposed turns and loops are especially sensitive. In urease, a flap covering the active site is the most sensitive part of the molecule and nearby loops show enhanced sensitivity. Below 180 K sensitivity is correlated with poor local packing, especially in thaumatin. At all temperatures, the component of the damage that is spatially uniform within the unit cell accounts for more than half of the total increase in the atomic B factors and correlates with changes in mosaicity. This component may arise from lattice-level, rather than local, disorder. The effects of primary structure on radiation sensitivity are small compared with those of tertiary structure, local packing, solvent accessibility and crystal contacts.

Determination of operating limits for radionuclides for a proposed landfill at Paducah Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Wang, J.C.; Lee, D.W.; Ketelle, R.H.; Lee, R.R.; Kocher, D.C.

1994-01-01

The operating limits for radionuclides in sanitary and industrial wastes were determined for a proposed landfill at the Paducah Gaseous Diffusion Plant (PGDP), Kentucky. These limits, which may be very small but nonzero, are not mandated by law or regulation but are needed for rational operation. The approach was based on analyses of the potential contamination of groundwater at the plant boundary and the potential exposure to radioactivity of an intruder at the landfill after closure. The groundwater analysis includes (1) a source model describing the disposal of waste and the release of radionuclides from waste to the groundwater, (2) site-specific groundwater flow and contaminant transport calculations, and (3) calculations of operating limits from the dose limit and conversion factors. The intruder analysis includes pathways through ingestion of contaminated vegetables and soil, external exposure to contaminated soil, and inhalation of suspended activity from contaminated soil particles. In both analyses, a limit on annual effective dose equivalent of 4 mrem (0.04 mSv) was adopted. The intended application of the results is to refine the radiological monitoring standards employed by the PGDP Health Physics personnel to determine what constitutes radioactive wastes, with concurrence of the Commonwealth of Kentucky

Stable isotope separation by thermal diffusion

International Nuclear Information System (INIS)

Vasaru, Gheorghe

2001-01-01

Thermal diffusion in both gaseous and liquid phase has been subject of extensive experimental and theoretical investigations, especially after the invention of K. Clusius and G. Dickel of the thermal diffusion column, sixty three years ago. This paper gives a brief overview of the most important research and developments performed during the time at the National Institute for Research and Development for Isotopic and Molecular Technology (ITIM) at Cluj - Napoca, Romania in the field of separation of stable isotopes by thermal diffusion. An retrospective analysis of the research and results concerning isotope separation by thermal diffusion entails the following conclusions: - thermal diffusion is an adequate method for hydrogen isotope separation (deuterium and tritium) and for noble gas isotope separation (He, Ne, Ar, Kr, Xe); - thermal diffusion is attractive also for 13 C enrichment using methane as raw material for separation, when annual yields of up to 100 g are envisaged; - lately, the thermal diffusion appears to be chosen as a final enrichment step for 17 O. An obvious advantage of this method is its non-specificity, i.e. the implied equipment can be utilized for isotope separation of other chemical elements too. Having in view the low investment costs for thermal diffusion cascades the method appears economically attractive for obtaining low-scale, laboratory isotope production. The paper has the following content: 1. The principle of method; 2. The method's application; 3. Research in the field of thermal diffusion at ITIM; 4. Thermal diffusion cascades for N, C, Ne, Ar and Kr isotope separation; 5. Conclusion

Inorganic soil and groundwater chemistry near Paducah Gaseous Diffusion Plant, Paducah, Kentucky

Energy Technology Data Exchange (ETDEWEB)

Moore, G.K. [Tennessee Univ., Knoxville, TN (United States)

1995-03-01

Near-surface soils, boreholes, and sediments near the Paducah Gaseous Diffusion Plant (PGDP) were sampled in 1989-91 as were monitoring wells, TVA wells, and privately-owned wells. Most wells were sampled two or three times. The resulting chemical analyses have been published in previous reports and have been previously described (CH2M HILL 1991, 1992; Clausen et al. 1992). The two reports by CH2M HILL are controversial, however, because, the concentrations of some constituents were reported to exceed background levels or drinking water standards and because both on-site (within the perimeter fence at PGDP) and off-site pollution was reported to have occurred. The groundwater samples upon which these interpretations were based may not be representative, however. The CH2M HILL findings are discussed in the report. The purpose of this report is to characterize the inorganic chemistry of groundwater and soils near PGDP, using data from the CH2M HILL reports (1991, 1992), and to determine whether or not any contamination has occurred. The scope is limited to analysis and interpretation of data in the CH2M HILL reports because previous interpretations of these data may not be valid, because samples were collected in a relatively short period of time at several hundred locations, and because the chemical analyses are nearly complete. Recent water samples from the same wells were not considered because the characterization of inorganic chemistry for groundwater and soil requirements only one representative sample and an accurate analysis from each location.

Inorganic soil and groundwater chemistry near Paducah Gaseous Diffusion Plant, Paducah, Kentucky

International Nuclear Information System (INIS)

Moore, G.K.

1995-03-01

Near-surface soils, boreholes, and sediments near the Paducah Gaseous Diffusion Plant (PGDP) were sampled in 1989-91 as were monitoring wells, TVA wells, and privately-owned wells. Most wells were sampled two or three times. The resulting chemical analyses have been published in previous reports and have been previously described (CH2M HILL 1991, 1992; Clausen et al. 1992). The two reports by CH2M HILL are controversial, however, because, the concentrations of some constituents were reported to exceed background levels or drinking water standards and because both on-site (within the perimeter fence at PGDP) and off-site pollution was reported to have occurred. The groundwater samples upon which these interpretations were based may not be representative, however. The CH2M HILL findings are discussed in the report. The purpose of this report is to characterize the inorganic chemistry of groundwater and soils near PGDP, using data from the CH2M HILL reports (1991, 1992), and to determine whether or not any contamination has occurred. The scope is limited to analysis and interpretation of data in the CH2M HILL reports because previous interpretations of these data may not be valid, because samples were collected in a relatively short period of time at several hundred locations, and because the chemical analyses are nearly complete. Recent water samples from the same wells were not considered because the characterization of inorganic chemistry for groundwater and soil requirements only one representative sample and an accurate analysis from each location

An interim report to the manager of the Paducah Gaseous Diffusion Plant from the Paducah Environmental Advisory Committee

International Nuclear Information System (INIS)

Jackson, G.D.

1987-01-01

The Paducah Environmental Advisory Committee was formed as: (1) an outgrowth of other Environmental Advisory Committees already in existence at Oak Ridge and other Martin Marietta Energy Systems plants; (2) a result of public concern following significant nuclear incidents at Bhopal and Chernobyl; (3) a result of the new direction and commitment of the management of the Paducah Gaseous Diffusion Plant following contract acquisition by Martin Marietta Energy Systems; and (4) a means of reducing and/or preventing local and/or public concern regarding the activities of and potential risks created by PGDP. This report discusses the following issues and concerns of the Committee arrived at through a series of meetings: (1) groundwater monitoring; (2) long-range tails storage; C-404, scrap yrads, and PCB and TCE cleanup; nuclear criticality plan and alarm systems; documentation of historical data regarding hazardous waste burial grounds; dosimeter badges; and asbestos handling and removal

An interim report to the manager of the Paducah Gaseous Diffusion Plant from the Paducah Environmental Advisory Committee

International Nuclear Information System (INIS)

Jackson, G.D.

1987-10-01

The Paducah Environmental Advisory Committee was formed as: (1) an outgrowth of other Environmental Advisory Committees already in existence at Oak Ridge and other Martin Marietta Energy Systems plants; (2) a result of public concern following significant nuclear incidents at Bhopal and Chernobyl; (3) a result of the new direction and commitment of the management of the Paducah Gaseous Diffusion Plant following contract acquisition by Martin Marietta Energy Systems; and (4) a means of reducing and/or preventing local and/or public concern regarding the activities of and potential risks created by PGDP. This report discusses the following issues and concerns of the Committee arrived at through a series of meetings: (1) groundwater monitoring; (2) long-range tails storage; C-404, scrap yrads, and PCB and TCE cleanup; nuclear criticality plan and alarm systems; documentation of historical data regarding hazardous waste burial grounds; dosimeter badges; and asbestos handling and removal

Diffusion coefficients of nickel chloride in aqueous solutions of lactose at T = 298.15 K and T = 310.15 K

Energy Technology Data Exchange (ETDEWEB)

Ribeiro, Ana C.F., E-mail: anacfrib@ci.uc.p [Department of Chemistry, University of Coimbra, 3004-535 Coimbra (Portugal); Gomes, Joselaine C.S., E-mail: leidygomes18@hotmail.co [Department of Chemistry, University of Coimbra, 3004-535 Coimbra (Portugal); Barros, Marisa C.F., E-mail: marisa.barros@gmail.co [Department of Chemistry, University of Coimbra, 3004-535 Coimbra (Portugal); Lobo, Victor M.M., E-mail: vlobo@ci.uc.p [Department of Chemistry, University of Coimbra, 3004-535 Coimbra (Portugal); Esteso, Miguel A., E-mail: miguel.esteso@uah.e [Departamento de Quimica Fisica, Facultad de Farmacia, Universidad de Alcala, 28871, Alcala de Henares (Madrid) (Spain)

2011-03-15

Binary mutual diffusion coefficients (interdiffusion coefficients) of nickel chloride in water at T = 298.15 K and T = 310.15 K, and at concentrations between (0.000 and 0.100) mol {center_dot} dm{sup -3}, using a Taylor dispersion method have been measured. These data are discussed on the basis of the Onsager-Fuoss and Pikal models. The equivalent conductance at infinitesimal concentration of the nickel ion in these solutions at T = 310.15 K has been estimated using these results. Through the same technique, ternary mutual diffusion coefficients (D{sub 11}, D{sub 22}, D{sub 12}, and D{sub 21}) for aqueous solutions containing NiCl{sub 2} and lactose, at T = 298.15 K and T = 310.15 K, and at different carrier concentrations were also measured. These data permit us to have a better understanding of the structure of these systems and the thermodynamic behaviour of NiCl{sub 2} in different media.

Electron Drift Properties in High Pressure Gaseous Xenon

Energy Technology Data Exchange (ETDEWEB)

Simón, A.; et al.

2018-04-05

Gaseous time projection chambers (TPC) are a very attractive detector technology for particle tracking. Characterization of both drift velocity and diffusion is of great importance to correctly assess their tracking capabilities. NEXT-White is a High Pressure Xenon gas TPC with electroluminescent amplification, a 1:2 scale model of the future NEXT-100 detector, which will be dedicated to neutrinoless double beta decay searches. NEXT-White has been operating at Canfranc Underground Laboratory (LSC) since December 2016. The drift parameters have been measured using $^{83m}$Kr for a range of reduced drift fields at two different pressure regimes, namely 7.2 bar and 9.1 bar. The results have been compared with Magboltz simulations. Agreement at the 5% level or better has been found for drift velocity, longitudinal diffusion and transverse diffusion.

Handling and treatment of low-level radioactive wastes from gaseous diffusion plants in the United States of America

International Nuclear Information System (INIS)

Wing, J.F.; Behrend, J.E.

1984-01-01

Gaseous diffusion plants in the United States of America currently generate very small quantities of low-level radioactive wastes. These wastes consist primarily of airborne effluent solid trapping media and liquid scrubber solutions, liquid effluent treatment sludges, waste oils and solvents, scrap metals and conventional combustible wastes such as floor sweepings, cleaning rags and shoe covers. In addition to waste emanating from current operations, large quantities of scrap metal generated during the Cascade Improvement Program are stored above ground at each of the diffusion plants. The radionuclides of primary concern are uranium and 99 Tc. Current radioactive waste treatment consists of uranium dissolution in weak acids followed by chemical precipitation and/or solvent extraction for uranium recovery. Current disposal operations consist of above ground storage of scrap metals, shallow land burial of inorganic solids and incineration of combustible wastes. With increased emphasis on reducing the potential for off-site radiological dose, several new treatment and disposal options are being studied and new projects are being planned. One project of particular interest involves the installation of a high temperature incinerator to thermally degrade hazardous organic wastes contaminated with low-level radioactive wastes. Other technologies being studied include fixation of uranium-bearing sludges in concrete before burial, decontamination of scrap metals by smelting and use of specially engineered centralized burial grounds. (author)

Uranium hexafluoride packaging tiedown systems overview at Portsmouth Gaseous Diffusion Plant, Piketon, Ohio

International Nuclear Information System (INIS)

Becker, D.L.; Green, D.J.; Lindquist, M.R.

1993-07-01

The Portsmouth Gaseous Diffusion Plant (PORTS) in Piketon, Ohio, is operated by Martin Marietta Energy Systems, Inc., through the US Department of Energy-Oak Ridge Operations Office (DOE-ORO) for the US Department of Energy-Headquarters, Office of Nuclear Energy. The PORTS conducts those operations that are necessary for the production, packaging, and shipment of uranium hexafluoride (UF 6 ). Uranium hexafluoride enriched uranium than 1.0 wt percent 235 U shall be packaged in accordance with the US Department of Transportation (DOT) regulations of Title 49 CFR Parts 173 (Reference 1) and 178 (Reference 2), or in US Nuclear Regulatory Commission (NRC) or US Department of Energy (DOE) certified package designs. Concerns have been expressed regarding the various tiedown methods and condition of the trailers being used by some shippers/carriers for international transport of the UF 6 cylinders/overpacks. Because of the concerns about international shipments, the US Department of Energy-Headquarters (DOE-HQ) Office of Nuclear Energy, through DOE-HQ Transportation Management Division, requested Westinghouse Hanford Company (Westinghouse Hanford) to review UF 6 packaging tiedown and shipping practices used by PORTS, and where possible and appropriate, provide recommendations for enhancing these practices. Consequently, a team of two individuals from Westinghouse Hanford visited PORTS on March 5 and 6, 1990, for the purpose of conducting this review. The paper provides a brief discussion of the review activities and a summary of the resulting findings and recommendations. A detailed reporting of the is documented in Reference 4

Adsorption and diffusion of hydrogen in Zircaloy-4

International Nuclear Information System (INIS)

Torres, E.; Desquines, J.; Baietto, M.C.; Coret, M.; Wehling, F.; Blat-Yrieix, M.; Ambard, A.

2015-01-01

Hydrogen in zirconium alloys is considered in many nuclear safety issues. Below 500 Celsius degrees, rather limited knowledge is available on the combined hydrogen adsorption at the sample surface and diffusion in the metal. A modeling of hydrogen gaseous charging has been established starting with a set of relevant laws and parameters derived from open literature. Simulating the hydrogen charging process requires simultaneous analysis of gaseous surface adsorption, hydrogen solid-solution diffusion and precipitation, when exceeding the material solubility limit. The modeling has been extended to reproduce the solid-gas exchange. Gaseous charging experiments have been performed at 420 C. degrees on Stress Relieved Annealed (SRA) Zircaloy-4 cladding samples to validate the model. The sample hydrogen content has been systematically measured after charging and compared to the calculated value thus providing a validation of the adsorption modeling. Complementary tests have been carried out on Recrystallized Annealed (RXA) Zircaloy-4 rods to characterize the combined diffusion and adsorption process. The hydrogen concentration distribution has been characterized using an inverse technique based on destructive analyses of the samples. This additional set of data was relevant for the validation of the hydrogen combined adsorption/diffusion modeling up to 420 C. degrees. (authors)

Ternary diffusion in Cu-rich fcc Cu–Al–Si alloys at 1073 K

Energy Technology Data Exchange (ETDEWEB)

Liu, Dandan [School of Materials Science and Engineering, Central South University, Changsha, Hunan 410083 (China); State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Zhang, Lijun [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Du, Yong, E-mail: yongducalphad@gmail.com [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Xu, Honghui [State Key Laboratory of Powder Metallurgy, Central South University, Changsha, Hunan 410083 (China); Jin, Zhanpeng [School of Materials Science and Engineering, Central South University, Changsha, Hunan 410083 (China)

2013-07-25

Highlights: •Interdiffusivities in Cu-rich fcc Cu–Al–Si alloys at 1073 K were determined. •The present results were compared with experimental data in boundary binary systems. •The present results were validated by thermodynamic constraints and Fick’s law. •The sign of ternary cross diffusivities was predicted in terms of thermodynamics. -- Abstract: Utilizing six groups of bulk diffusion couples and with electron probe microanalysis technique, the composition dependence of ternary interdiffusion coefficients in Cu-rich fcc Cu–Al–Si alloys at 1073 K were determined by the Matano-Kirkaldy method. Using a three-dimensional representation, the obtained main ternary diffusion coefficients were found to be consistent with the experimental data in boundary binaries available in the literature. The reliability of the obtained interdiffusivities was further validated by thermodynamic constraints as well as by Fick’s second law applied to numerical simulation. The sign of the ternary cross diffusivities in fcc Cu–Al–Si alloys, which shows a noticeable effect on microstructure, was also successfully predicted in terms of thermodynamics.

Ternary diffusion in Cu-rich fcc Cu–Al–Si alloys at 1073 K

International Nuclear Information System (INIS)

Liu, Dandan; Zhang, Lijun; Du, Yong; Xu, Honghui; Jin, Zhanpeng

2013-01-01

Highlights: •Interdiffusivities in Cu-rich fcc Cu–Al–Si alloys at 1073 K were determined. •The present results were compared with experimental data in boundary binary systems. •The present results were validated by thermodynamic constraints and Fick’s law. •The sign of ternary cross diffusivities was predicted in terms of thermodynamics. -- Abstract: Utilizing six groups of bulk diffusion couples and with electron probe microanalysis technique, the composition dependence of ternary interdiffusion coefficients in Cu-rich fcc Cu–Al–Si alloys at 1073 K were determined by the Matano-Kirkaldy method. Using a three-dimensional representation, the obtained main ternary diffusion coefficients were found to be consistent with the experimental data in boundary binaries available in the literature. The reliability of the obtained interdiffusivities was further validated by thermodynamic constraints as well as by Fick’s second law applied to numerical simulation. The sign of the ternary cross diffusivities in fcc Cu–Al–Si alloys, which shows a noticeable effect on microstructure, was also successfully predicted in terms of thermodynamics

Method and apparatus for rapid adjustment of process gas inventory in gaseous diffusion cascades

International Nuclear Information System (INIS)

Dyer, R.H.; Fowler, A.H.; Vanstrum, P.R.

1977-01-01

The invention relates to an improved method and system for making relatively large and rapid adjustments in the process gas inventory of an electrically powered gaseous diffusion cascade in order to accommodate scheduled changes in the electrical power available for cascade operation. In the preferred form of the invention, the cascade is readied for a decrease in electrical input by simultaneously withdrawing substreams of the cascade B stream into respective process-gas-freezing and storage zones while decreasing the datum-pressure inputs to the positioning systems for the cascade control valves in proportion to the weight of process gas so removed. Consequently, the control valve positions are substantially unchanged by the reduction in invention, and there is minimal disturbance of the cascade isotopic gradient. The cascade is readied for restoration of the power cut by simultaneously evaporating the solids in the freezing zones to regenerate the process gas substreams and introducing them to the cascade A stream while increasing the aforementioned datum pressure inputs in proportion to the weight of process gas so returned. In the preferred form of the system for accomplishing these operations, heat exchangers are provided for freezing, storing, and evaporating the various substreams. Preferably, the heat exchangers are connected to use existing cascade auxiliary systems as a heat sink. A common control is employed to adjust and coordinate the necessary process gas transfers and datum pressure adjustments

Easy measurement of diffusion coefficients of EGFP-tagged plasma membrane proteins using k-space Image Correlation Spectroscopy

DEFF Research Database (Denmark)

Christensen, Eva Arnspang; Koffman, Jennifer Skaarup; Marlar, Saw

2014-01-01

Lateral diffusion and compartmentalization of plasma membrane proteins are tightly regulated in cells and thus, studying these processes will reveal new insights to plasma membrane protein function and regulation. Recently, k-Space Image Correlation Spectroscopy (kICS)1 was developed to enable...... routine measurements of diffusion coefficients directly from images of fluorescently tagged plasma membrane proteins, that avoided systematic biases introduced by probe photophysics. Although the theoretical basis for the analysis is complex, the method can be implemented by nonexperts using a freely...... to the correlation function yields the diffusion coefficient. This paper provides a step-by-step guide to the image analysis and measurement of diffusion coefficients via kICS. First, a high frame rate image sequence of a fluorescently labeled plasma membrane protein is acquired using a fluorescence microscope Then...

Portsmouth Gaseous Diffusion Plant Decontamination and Decommissioning Program surveillance and maintenance plan, FY 1993--2002

International Nuclear Information System (INIS)

Schloesslin, W.

1992-11-01

The Decontamination and Decommissioning (D ampersand D) Program at the Portsmouth Gaseous Diffusion Plant (PORTS) is part of the Environmental Restoration (ER) and Waste Management (WM) Programs (ERWM). The objective of the ER Program is to provide PORTS the capability to meet applicable environmental regulations through facility development activities and site remedial actions. The WM Program supports the ER Program. The D ampersand D Program provides collective management of the sites within the plant which require decontamination and decommissioning, prioritizes those areas in terms of health, safety and environmental concerns, and implements the appropriate level of remedial action. The D ampersand D Program provides support to facilities which formerly served one or more of the many Plant functions. Program activities include (1) surveillance and maintenance of facilities awaiting decommissioning; (2) planning safe and orderly facility decommissioning; and (3) implementing a program to accomplish facility disposition in a safe, cost effective, and timely manner. In order to achieve the first objective, a formal plan which documents the surveillance and maintenance needs for each inactive facility has been prepared. This report provides this documentation for the PORTS facilities currently included in the D ampersand D Program and includes projected resource requirements for the planning period of FY 1993 through FY 2002

Treatment of Plants with Gaseous Ethylene and Gaseous Inhibitors of Ethylene Action.

Science.gov (United States)

Tucker, Mark L; Kim, Joonyup; Wen, Chi-Kuang

2017-01-01

The gaseous nature of ethylene affects not only its role in plant biology but also how you treat plants with the hormone. In many ways, it simplifies the treatment problem. Other hormones have to be made up in solution and applied to some part of the plant hoping the hormone will be taken up into the plant and translocated throughout the plant at the desired concentration. Because all plant cells are connected by an intercellular gas space the ethylene concentration you treat with is relatively quickly reached throughout the plant. In some instances, like mature fruit, treatment with ethylene initiates autocatalytic synthesis of ethylene. However, in most experiments, the exogenous ethylene concentration is saturating, usually >1 μL L -1 , and the synthesis of additional ethylene is inconsequential. Also facilitating ethylene research compared with other hormones is that there are inhibitors of ethylene action 1-MCP (1-methylcyclopropene) and 2,5-NBD (2,5-norbornadiene) that are also gases wherein you can achieve nearly 100% inhibition of ethylene action quickly and with few side effects. Inhibitors for other plant hormones are applied as a solution and their transport and concentration at the desired site is not always known and difficult to measure. Here, our focus is on how to treat plants and plant parts with the ethylene gas and the gaseous inhibitors of ethylene action.

Issues and recommendations related to replacement of CFC-114 at the uranium enrichment gaseous diffusion plant

International Nuclear Information System (INIS)

Anderson, B.L.; Banaghan, E.

1993-01-01

The operating uranium enrichment gaseous diffusion plants (GDPs) in Portsmouth, Ohio and Paducah, Kentucky, which are operated for the United States Department for Energy by Martin Marietta Energy Systems (MMES), currently use a chlorofluorocarbon (CFC-114) as the primary process stream coolant. Due to recent legislation embodied in the Clean Air Act, the production of this and other related chlorofluorocarbons (CFCS) are to be phased out with no production occurring after 1995. Since the plants lose approximately 500,000 pounds per year of this process stream coolant through various leaks, the GDPs are faced with the challenge of identifying a replacement coolant that will allow continued operation of the plants. MMES formed the CFC Task Team to identify and solve the various problems associated with identifying and implementing a replacement coolant. This report includes a review of the work performed by the CFC Task Team, and recommendations that were formulated based on this review and upon original work. The topics covered include; identifying a replacement coolant, coolant leak detection and repair efforts, coolant safety concerns, coolant level sensors, regulatory issues, and an analytical decision analysis

EURODIF company - Tricastin gaseous diffusion plant. Requests following the safety re-evaluation of the facility after 20 years of operation

International Nuclear Information System (INIS)

2000-01-01

This decision from the French authority of nuclear safety (ASN) concerns the safety reevaluation of the EURODIF plant ('Georges Besse plant') of the Tricastin site at Pierrelatte (France) which uses the gaseous diffusion process to separate the uranium isotopes. Since the last safety reevaluation in 1988, several points have been improved: reduction of the frequency and importance of uranium hexafluoride leaks (control of the pitting corrosion in the exchangers), no incident linked with exo-thermal reactions or explosions, a mastery of the exposure to ionizing radiations etc.. On the other hand, several points need improvement: the prevention of criticality risks, the earthquake resistance of some structures, and the integration of some accident scenarios (aircraft crash, UF 6 leak) in the emergency plan to avoid the fast release of toxic materials in the environment. These points are detailed in the document. (J.S.)

Thermal conductivity and diffusivity of climax stock quartz monzonite at high pressure and temperature

International Nuclear Information System (INIS)

Durham, W.B.; Abey, A.E.

1981-11-01

Measurements of thermal conductivity and thermal diffusivity have been made on two samples of Climax Stock quartz monzonite at pressures between 3 and 50 MPa and temperatures between 300 and 523 0 K. Following those measurements the apparatus was calibrated with respect to the thermal conductivity measurement using a reference standard of fused silica. Corrected thermal conductivity of the rock indicates a value at room temperature of 2.60 +- 0.25 W/mK at 3 MPa increasing linearly to 2.75 +- 0.25 W/mK at 50 MPa. These values are unchanged (+- 0.07 W/mK) by heating under 50-MPa pressure to as high as 473 0 K. The conductivity under 50-MPa confining pressure falls smoothly from 2.75 +- 0.25 W/mK at 313 0 K to 2.15 +- 0.25 W/mK at 473 0 K. Thermal diffusivity at 300 0 K was found to be 1.2 +- 0.4 X 10 -6 m 2 /s and shows approximately the same pressure and temperature dependencies as the thermal conductivity

Determination of Concentration Dependent Diffusion Coefficients of Carbon in Expanded Austenite

DEFF Research Database (Denmark)

Hummelshøj, Thomas Strabo; Christiansen, Thomas; Somers, Marcel A. J.

2008-01-01

Abstract. In the present paper various experimental procedures to experimentally determine the concentration dependent diffusion coefficient of carbon in expanded austenite are evaluated. To this end thermogravimetric carburization was simulated for various experimental conditions and the evaluated...... composition dependent diffusivity of carbon derived from the simulated experiments was compared with the input data. The most promising procedure for an accurate determination is shown to be stepwise gaseous carburizing of thin foils in a gaseous atmosphere; the finer the stepsize, the more accurate...

Modeling and analyses of postulated UF6 release accidents in gaseous diffusion plant

International Nuclear Information System (INIS)

Kim, S.H.; Taleyarkhan, R.P.; Keith, K.D.; Schmidt, R.W.; Carter, J.C.; Dyer, R.H.

1995-10-01

Computer models have been developed to simulate the transient behavior of aerosols and vapors as a result of a postulated accident involving the release of uranium hexafluoride (UF 6 ) into the process building of a gaseous diffusion plant. UF 6 undergoes an exothermic chemical reaction with moisture (H 2 O) in the air to form hydrogen fluoride (HF) and radioactive uranyl fluoride (UO 2 F 2 ). As part of a facility-wide safety evaluation, this study evaluated source terms consisting of UO 2 F 2 as well as HF during a postulated UF 6 release accident in a process building. In the postulated accident scenario, ∼7900 kg (17,500 lb) of hot UF 6 vapor is released over a 5 min period from the process piping into the atmosphere of a large process building. UO 2 F 2 mainly remains as airborne-solid particles (aerosols), and HF is in a vapor form. Some UO 2 F 2 aerosols are removed from the air flow due to gravitational settling. The HF and the remaining UO 2 F 2 are mixed with air and exhausted through the building ventilation system. The MELCOR computer code was selected for simulating aerosols and vapor transport in the process building. MELCOR model was first used to develop a single volume representation of a process building and its results were compared with those from past lumped parameter models specifically developed for studying UF 6 release accidents. Preliminary results indicate that MELCOR predicted results (using a lumped formulation) are comparable with those from previously developed models

Research and economic evaluation on uranium enrichment by gaseous diffusion process in Japan

International Nuclear Information System (INIS)

Aochi, T.; Takahashi, S.

1977-01-01

Research and development works on uranium enrichment by gaseous diffusion process were carried out by JAERI, IPCR and industries since 1965. There are two important keys to reduce the uranium separation cost. One is the characteristics of the barrier and the other is financing and/or political planning. The technics to prepare the barrier with pore diameter of 40A have been developed with polytetrafluoroethylene, alumina and nickel. The experiment on corrosion behavior of PTFE barriers has shown better characteristics than the others. In the field of engineering research, the adiabatic efficiency of axial compressor for UF 6 was resulted to as high as 90% by long term operation tests. Based on these experimental data, techno-economic evaluation on a uranium enrichment plant was carried out with regard to the optimization of separation efficiency, numbers of step and operating conditions of the plant. Sensitivity in the separation cost were calculated as a function of pore diameter, uranium hexafluoride cost, plant capacity, electric power cost, and the plant annual expenditure. A financing plan must be such as to achieve 1. maximization of debt in a percentage of total capitalization 2. off-take contracts to utilities as security for financing 3. minimization of risks to equity and achievable cost of capital. Therefore the cash flow analysis and the schedule for construction and operation are very important for a economical feasibility of a uranium enrichment plant. To minimize the risk, not only economical but also political environment are important. The governmental supports and international agreements will be necessary

Uranium hexafluoride packaging tiedown systems overview at Portsmouth Gaseous Diffusion Plant, Piketon, Ohio

International Nuclear Information System (INIS)

Becker, D.L.; Lindquist, M.R.

1993-01-01

The Portsmouth Gaseous Diffusion Plant (PORTS) in Piketon, Ohio, is operated by Martin Marietta Energy Systems, Inc., through the US Department of Energy-Oak Ridge Operations Office (DOE-ORO) for the US Department of Energy-Headquarters, Office of Nuclear Energy. The PORTS conducts those operations that are necessary for the production, packaging, and shipment of enriched uranium hexafluoride (UF 6 ). Uranium hexafluoride enriched greater than 1.0 wt percent 235 U shall be packaged in accordance with the US Department of Transportation (DOT) regulations of Title 49 CFR Parts 173 and 178, or in US Nuclear Regulatory Commission (NRC) or US Department of Energy (DOE) certified package designs. Concerns have been expressed regarding the various tiedown methods and condition of the trailers being used by some shippers/carriers for international transport of the UF 6 cylinders/overpacks. International shipments typically are not made using dedicated trailers, and numerous trailers have been received at PORTS with improperly and potentially dangerously secured overpacks. Because of the concerns about international shipments, the US Department of Energy-Headquarters (DOE-HQ) Office of Nuclear Energy, through DOE-HQ Transportation Management Division, requested Westinghouse Hanford Company (Westinghouse Hanford) to review UF 6 packaging tiedown and shipping practices used by PORTS; and where possible and appropriate, provide recommendations for enhancing these practices. Consequently, a team of two individuals from Westinghouse Hanford visited PORTS on March 5 and 6, 1990, for the purpose of conducting this review. The paper provides a brief discussion of the review activities and a summary of the resulting findings and recommendations

Tiger Team Assessment of the Oak Ridge K-25 Site

International Nuclear Information System (INIS)

1991-12-01

The Office of Special Projects in the Office of the Assistant Secretary for Environment, Safety, and Health (EH) has the responsibility to conduct Tiger Team Assessments for the Secretary of Energy. This report documents the Tiger Team Assessment of the Oak Ridge K-25 Site (K-25 Site), Oak Ridge, Tennessee. The purpose of the Assessment is to provide the Secretary of Energy with concise information on the: current ES ampersand H compliance status of the Site and the vulnerabilities associated with that compliance status; root causes for noncompliance; adequacy of DOE and site contractor ES ampersand H management programs; adequacy of response actions developed to address identified problem areas; and adequacy of ES ampersand H self-assessments and the institutionalization of the self-assessment process at the K-25 Site

Temporal relationships between the variations of diffuse gaseous emanations and the explosive activity of some active volcanoes of Costa-Rica, examples at the Arenal, Irazu and at the Rincon de la Vieja

International Nuclear Information System (INIS)

Baubron, J.C.; Allard, P.; Hammouya, G.; Soto, G.J.

1996-01-01

The surveillance of the temporal evolution of radon and helium concentrations in the carbon dioxide of crater fumaroles and gaseous emanations is performed since 1992 on the Irazu, Arenal, Poas and Rincon de la Vieja volcanoes in Costa-Rica. The 3 He/ 4 He ratio is used as an indicator of the deep origin of the volcanic gas while radon is an indicator of the CO 2 flux. Radon measurements performed on the Irazu show a continuous decay of radon concentration in the intra-crater fumaroles with an important increase of the gaseous flux since 1992. On the contrary, the external fumaroles on the NW flank were characterized by an important increase in radon concentration in 1994 with a stable flux. The radon surveillance performed in soils around the volcano has shown an intense increase of the diffuse gaseous flows probably linked to the micro-seismic activity of the volcano. Similar observations are reported for the Rincon de la Vieja volcano and correlated with its eruptive history and its phreatic and phreato-magmatic activity. Short paper. (J.S.)

Gaseous nebulae

International Nuclear Information System (INIS)

Williams, R.E.

1976-01-01

Gaseous nebulae are large, tenuous clouds of ionized gas that are associated with hot stars and that emit visible light because of the energy that they receive from the ultraviolet radiation of the stars. Examples include H II regions, planetary nebulae, and nova/supernova remnants. The emphasis is on the physical processes that occur in gaseous nebulae as opposed to a study of the objects themselves. The introduction discusses thermodynamic vs. steady-state equilibrium and excitation conditions in a dilute radiation field. Subsequent sections take up important atomic processes in gaseous nebulae (particle--particle collision rates, radiative interaction rates, cross sections), the ionization equilibrium (sizes of H II regions, ionization of the heavier elements), kinetic temperature and energy balance (heating of the electrons, cooling of the electrons), and the spectra of gaseous nebulae (line fluxes in nebulae). 7 figures, 5 tables

Microgravity survey of the Oak Ridge K-25 Site, Oak Ridge, Tennessee

International Nuclear Information System (INIS)

Kaufmann, R.D.

1996-05-01

Karst features are known to exist within the carbonate bedrock of the Oak Ridge K-25 Site and may play an important role in groundwater flow and contaminant migration. This report discusses the results of a microgravity survey of the Oak Ridge K-25 Site. The main objective of the survey is to identify areas containing bedrock cavities. Secondary objectives included correlating the observed gravity to the geology and to variations in overburden thickness. The analysis includes 11 profile lines that are oriented perpendicular to the geologic strike and major structures throughout the K-25 Site. The profile lines are modeled in an effort to relate gravity anomalies to karst features such as concentrations of mud-filled cavities. Regolith thickness and density data provided by boreholes constrain the models. Areally distributed points are added to the profile lines to produce a gravity contour map of the site. In addition, data from the K-901 area are combined with data from previous surveys to produce a high resolution map of that site. The K-25 Site is located in an area of folded and faulted sedimentary rocks within the Appalachian Valley and Ridge physiographic province. Paleozoic age rocks of the Rome Formation, Knox Group, and Chickamauga Supergroup underlie the K-25 Site and contain structures that include the Whiteoak Mountain Fault, the K-25 Fault, a syncline, and an anticline. The mapped locations of the rock units and complex structures are currently derived from outcrop and well log analysis

Assessment and interpretation of cross- and down-hole seismograms at the Paducah Gaseous Diffusion Plant

Energy Technology Data Exchange (ETDEWEB)

Staub, W.P.; Wang, J.C. (Oak Ridge National Lab., TN (United States)); Selfridge, R.J. (Automated Sciences Group, (United States))

1991-09-01

This paper is an assessment and interpretation of cross-and down-hole seismograms recorded at four sites in the vicinity of the Paducah Gaseous Diffusion Plant (PGDP). Arrival times of shear (S-) and compressional (P-) waves are recorded on these seismograms in milliseconds. Together with known distances between energy sources and seismometers lowered into boreholes, these arrival times are used to calculate S- and P-wave velocities in unconsolidated soils and sediments that overlie bedrock approximately 320 ft beneath PGDP. The soil columns are modified after an earlier draft by ERC Environmental and Energy Services Company (ERCE), 1990. In addition to S- and P- wave velocity estimates from this paper, the soil columns contain ERCE's lithologic and other geotechnical data for unconsolidated soils and sediments from the surface to bedrock. Soil columns for Sites 1 through 4 and a site location map are in Plates 1 through 5 of Appendix 6. The velocities in the four columns are input parameters for the SHAKE computer program, a nationally recognized computer model that simulates ground response of unconsolidated materials to earthquake generated seismic waves. The results of the SHAKE simulation are combined with predicted ground responses on rock foundations (caused by a given design earthquake) to predict ground responses of facilities with foundations placed on unconsolidated materials. 3 refs.

ICP-MS measurement of silver diffusion coefficient in graphite IG-110 between 1048K and 1284K

Science.gov (United States)

Carter, L. M.; Seelig, J. D.; Brockman, J. D.; Robertson, J. D.; Loyalka, S. K.

2018-01-01

Silver-110m has been shown to permeate intact silicon carbide and pyrolytic carbon coating layers of the TRISO fuel particles during normal High Temperature Gas-Cooled Reactor (HTGR) operational conditions. The diffusion coefficients for silver in graphite IG-110 measured using a release method designed to simulate HTGR conditions of high temperature and flowing helium in the temperature range 1048-1253 K are reported. The measurements were made using spheres milled from IG-110 graphite that were infused with silver using a pressure vessel technique. The Ag diffusion was measured using a time release technique with an ICP-MS instrument for detection. The results of this work are:

Thermal conductivity and diffusivity of climax stock quartz monzonite at high pressure and temperature

Energy Technology Data Exchange (ETDEWEB)

Durham, W.B.; Abey, A.E.

1981-11-01

Measurements of thermal conductivity and thermal diffusivity have been made on two samples of Climax Stock quartz monzonite at pressures between 3 and 50 MPa and temperatures between 300 and 523{sup 0}K. Following those measurements the apparatus was calibrated with respect to the thermal conductivity measurement using a reference standard of fused silica. Corrected thermal conductivity of the rock indicates a value at room temperature of 2.60 +- 0.25 W/mK at 3 MPa increasing linearly to 2.75 +- 0.25 W/mK at 50 MPa. These values are unchanged (+- 0.07 W/mK) by heating under 50-MPa pressure to as high as 473{sup 0}K. The conductivity under 50-MPa confining pressure falls smoothly from 2.75 +- 0.25 W/mK at 313{sup 0}K to 2.15 +- 0.25 W/mK at 473{sup 0}K. Thermal diffusivity at 300{sup 0}K was found to be 1.2 +- 0.4 X 10{sup -6} m{sup 2}/s and shows approximately the same pressure and temperature dependencies as the thermal conductivity.

Research on and economic evaluation of uranium enrichment by gaseous diffusion in Japan

International Nuclear Information System (INIS)

Aochi, T.; Takahashi, S.

1977-01-01

Research and development on uranium enrichment by the gaseous diffusion process have been carried out by the Japan Atomic Energy Research Institute, the Institute of Physical and Chemical Research, and industries since 1965. The paper describes the two important keys to reducing the cost of uranium separation. One is the characteristics of barriers and the other is financing and/or political planning. The techniques of preparing a barrier with pore diameter 40A have been developed with polytetrafluoroethylene (PTFE), alumina and nickel. Experiments on corrosion behaviour have indicated that PTFE barriers are the most favourable. In the field of engineering research, the adiabatic efficiency of the axial compressor for UF 6 was raised to as high as 90% by long-term operation tests. Based on these experimental data, technico-economic evaluation of a uranium enrichment plant was carried out for optimization of separation efficiency, number of steps and plant operating conditions. Sensitivity in the separation cost was calculated as a function of pore diameter, cost of uranium hexafluoride, plant capacity, cost of electric power, and annual expenditure of the plant. A finance plan must be such as to achieve: (a) maximization of debt in a percentage of total capital; (b) off-take contracts to utilities as security for financing; (c) minimization of risks to equity and achievable cost of capital. Therefore, the cash flow analysis and the schedule for construction and operation are very important for the economic feasibility of a uranium enrichment plant. To minimize the risk, the economic as well as the political environment is important. Government support and international agreements are necessary. (author)

Assessment of the influences of groundwater colloids on the migration of technetium-99 at the Paducah Gaseous Diffusion Plant Site in Paducah, Kentucky

International Nuclear Information System (INIS)

Gu, B.; McDonald, J.A.; McCarthy, J.F.; Clausen, J.L.

1994-07-01

This short report summarizes the influences of groundwater colloids on the migration/transport of 99 Tc at the Paducah Gaseous Diffusion Plant (PGDP) site in Paducah, Kentucky. Limited data suggest that inorganic colloidal materials (e.g., aluminosilicate clay minerals) may not play a significant role in the retention and transport of Tc. Studies by size fractionation reveal that both Tc and natural organic matter (NOM) are largely present in the -8 mol/L or parts per billion), regardless of the redox conditions, Tc will stay in solution phase as TC(IV) or Tc(VII). The mechanisms of adsorption/association vs precipitation must be understood under reduced and low Tc conditions so that strategic plans for remediation of Tc contaminated soils and groundwaters can be developed

Enhanced Oxygen Diffusion Within the Internal Oxidation Zone of Alloy 617 in Controlled Impurity Helium Environments from 1023 K to 1123 K (750 °C to 850 °C)

Science.gov (United States)

Gulsoy, Gokce; Was, Gary S.

2015-04-01

Alloy 617 was exposed to He-CO-CO2 environments with of either 9 or 1320 at temperatures from 1023 K to 1123 K (750 °C to 850 °C) to determine the oxygen diffusion coefficients within the internal oxidation zone of the alloy. The oxygen diffusion coefficients determined based on both intergranular and transgranular oxidation rates were several orders of magnitude greater than those reported in pure nickel and in nickel-based binary alloys, indicating that the rapid internal aluminum oxidation of Alloy 617 was primarily due to enhanced oxygen diffusion along the incoherent Al2O3-alloy interfaces. The range of activation energy values determined for oxygen diffusion associated with the intergranular aluminum oxidation was from 149.6 to 154.7 kJ/mol, and that associated with the transgranular aluminum oxidation was from 244.7 to 283.5 kJ/mol.

Model for absorption and release of gaseous materials by forest canopies

International Nuclear Information System (INIS)

Murphy, C.E. Jr.

1976-01-01

A model of the physical processes defining the absorption and release of materials by a forest canopy has been developed. The model deals with the turbulent transport of gaseous materials in the surface boundary layer near the canopy, the turbulent transport in the canopy atmosphere, the transport through the boundary layer near the leaf and soil surface, and the solution of the gaseous materials in intracellular fluids and subsequent diffusion into the leaf cells. The model is used to simulate the uptake of molecular tritium by the forest canopy and the subsequent release of tritiated water. Results of dynamic simulations of tritium uptake and release are compared with data collected at the time of a release of molecular tritium to the atmosphere

Oak Ridge K-25 Site Technology Logic Diagram

Energy Technology Data Exchange (ETDEWEB)

Fellows, R.L. (ed.)

1993-02-26

The Oak Ridge K-25 Technology Logic Diagram (TLD), a decision support tool for the K-25 Site, was developed to provide a planning document that relates environmental restoration (ER) and waste management (WN) problems at the Oak Ridge K-25 Site. The TLD technique identifies the research necessary to develop these technologies to a state that allows for technology transfer and application to waste management, remediation, decontamination, and decommissioning activities. The TLD consists of four separate volumes-Vol. 1, Vol. 2, Vol. 3A, and Vol. 3B. Volume 1 provides introductory and overview information about the TLD. Volume 2 contains logic diagrams. Volume 3 has been divided into two separate volumes to facilitate handling and use. This volume 3 B provides the Technology Evaluation Data Sheets (TEDS) for ER/WM activities (Remedial Action Robotics and Automation, Waste Management) that are referenced by a TEDS code number in Vol. 2 of the TLD. Each of these sheets represents a single logic trace across the TLD. These sheets contain more detail than each technology in Vol. 2. The TEDS are arranged alphanumerically by the TEDS code number in the upper right corner of each data sheet. Volume 3 can be used in two ways: (1) technologies that are identified from Vol. 2 can be referenced directly in Vol. 3 by using the TEDS codes, and (2) technologies and general technology areas (alternatives) can be located in the index in the front of this volume.

A 25 kA, 2T, 78 kJ, 52 litre superconducting test coil. Strength calculations and construction

NARCIS (Netherlands)

ten Kate, Herman H.J.; Holtslag, A.H.M.; Knoben, J.; Steffens, H.A.; van de Klundert, L.J.M.

1983-01-01

Within the scope of our research program for a 25 kA superconducting rectifier, we have built a 25 kA s.c. coil being a single layer solenoid with a bore of 0.45 meter and a volume of 52 litre. The starting point for the design was to avoid any metallic structural material. This unique coil consists

In Situ Chemical Oxidation Through Lance Permeation at the Portsmouth Gaseous Diffusion Plant (PORTS)

International Nuclear Information System (INIS)

Martin, M.Z.

2003-01-01

In situ chemical oxidation through lance permeation (ISCO-LP) is an emerging remediation technology in which chemical oxidants (such as potassium or sodium permanganate) are delivered to the subsurface using vertical lance-like injectors. It is applicable to sites with oxidizable contaminants such as chlorinated solvents and fuel hydrocarbons. Because vertical lance injections can be deployed at relatively close spacing, ISCO-LP potentially can be used to clean-up contamination in low-permeability media. This document provides information that can help potential users determine whether ISCO-LP would apply to a particular environmental management problem. It contains a general description of the technology (Section 2), performance data from a field demonstration (Section 3), an assessment of technology applicability (Section 4), a summary of cost elements (Section 5), and a list of regulatory, environmental safety and health issues (Section 6). It is patterned after the Innovative Technology Summary Reports (ITSR) published by the Department of Energy's (DOE) Office of Science and Technology under the Subsurface Contaminants Focus Area (SCFA). As in the previously published ITSRs, the technology described in this report was developed through funding from SCFA. Most of the information contained in this report was obtained from a field demonstration of ISCO-LP conducted in July-August 2000 at DOE's Portsmouth Gaseous Diffusion Plant (PORTS). The field test was not completed due to an accident that caused a field worker serious injuries. Although performance assessment data are very limited, the field test highlighted important health and safety issues that must be considered by site managers and technology vendors interested in implementing ISCO-LP

Development of gaseous photomultiplier

International Nuclear Information System (INIS)

Tokanai, F.; Sumiyoshi, T.; Sugiyama, H.; Okada, T.

2014-01-01

We have been developing gaseous photomultiplier tubes (PMTs) with alkali photocathode combined with micropattern gas detectors (MPGDs). The potential advantage of the gaseous PMT is that it can achieve a very large effective area with adequate position and timing resolutions. In addition, it will be easily operated under a very high magnetic field, compared with the conventional vacuum-based PMT. To evaluate the gaseous PMTs filled with Ne and Ar based gas mixture, we have developed gaseous PMTs with an alkali photocathode combined with MPGDs such as a glass capillary plate, GEM, and Micromegas detector. We describe the recent development of the gaseous PMTs, particularly the production of the photocathode, gas gain, ion and photon feedbacks, quantum efficiency, and the characteristics in the magnetic field environment. (author)

Apparatus for diffusion separation

International Nuclear Information System (INIS)

Nierenberg, W.A.

1976-01-01

A diffuser separator apparatus is described which comprises a plurality of flow channels in a single stage. Each of said channels has an inlet port and an outlet port and a constant cross sectional area between said ports. At least a portion of the defining surface of each of said channels is a diffusion separation membrane, and each of said channels is a different cross sectional area. Means are provided for connecting said channels in series so that each successive channel of said series has a smaller cross sectional area than the previous channel of said series. Also provided are a source of gaseous mixture, individual means for flowing said gaseous mixture to the inlet port of each of said channels, gas receiving and analyzing means, individual means for flowing gas passing from each of said outlet ports and means for flowing gas passing through said membranes to said receiving and analyzing means, and individual means for connecting the outlet port of each channel with the inlet port of the channel having the next smaller cross sectional area

Nitrogen-system safety study: Portsmouth Gaseous Diffusion Plant

International Nuclear Information System (INIS)

1982-07-01

The Department of Energy has primary responsibility for the safety of operations at DOE-owned nuclear facilities. The guidelines for the analysis of credible accidents are outlined in DOE Order 5481.1. DOE has requested that existing plant facilities and operations be reviewed for potential safety problems not covered by standard industrial safety procedures. This review is being conducted by investigating individual facilities and documenting the results in Safety Study Reports which will be compiled to form the Existing Plant Final Safety Analysis Report which is scheduled for completion in September, 1984. This Safety Study documents the review of the Plant Nitrogen System facilities and operations and consists of Section 4.0, Facility and Process Description, and Section 5.0, Accident Analysis, of the Final Safety Analysis Report format. The existing nitrogen system consists of a Superior Air Products Company Type D Nitrogen Plant, nitrogen storage facilities, vaporization facilities and a distribution system. The system is designed to generate and distribute nitrogen gas used in the cascade for seal feed, buffer systems, and for servicing equipment when exceptionally low dew points are required. Gaseous nitrogen is also distributed to various process auxiliary buildings. The average usage is approximately 130,000 standard cubic feet per day

Report on the biological monitoring program at Paducah Gaseous Diffusion Plant December 1993 to December 1994

Energy Technology Data Exchange (ETDEWEB)

Kszos, L.A. [ed.

1996-05-01

On September 24, 1987, the Commonwealth of Kentucky Natural Resources and Environmental Protection Cabinet issued an Agreed Order that required the development of a Biological Monitoring Program (BMP) for the Paducah Gaseous Diffusion Plant (PGDP). The PGDP BMP was implemented in 1987 by the University of Kentucky. Research staff of the Environmental Sciences Division (ESD) at Oak Ridge National Laboratory (ORNL) served as reviewers and advisers to the University of Kentucky. Beginning in fall 1991, ESD added data collection and report preparation to its responsibilities for the PGDP BMP. The goals of BMP are to (1) demonstrate that the effluent limitations established for PGDP protect and maintain the use of Little Bayou and Big Bayou creeks for growth and propagation of fish and other aquatic life, (2) characterize potential environmental impacts, (3) document the effects of pollution abatement facilities on stream biota, and (4) recommend any program improvements that would increase effluent treatability. In September 1992, a renewed Kentucky Pollutant Discharge Elimination System (KPDES) permit was issued to PGDP. The BMP for PGDP consists of three major tasks: (1) effluent and ambient toxicity monitoring, (2) bioaccumulation studies, and (3) ecological surveys of stream communities (i.e., benthic macroinvertebrates and fish). This report includes ESD activities occurring from December 1993 to December 1994, although activities conducted outside this time period are included as appropriate.

Report on the biological monitoring program at Paducah Gaseous Diffusion Plant December 1993 to December 1994

International Nuclear Information System (INIS)

Kszos, L.A.

1996-05-01

On September 24, 1987, the Commonwealth of Kentucky Natural Resources and Environmental Protection Cabinet issued an Agreed Order that required the development of a Biological Monitoring Program (BMP) for the Paducah Gaseous Diffusion Plant (PGDP). The PGDP BMP was implemented in 1987 by the University of Kentucky. Research staff of the Environmental Sciences Division (ESD) at Oak Ridge National Laboratory (ORNL) served as reviewers and advisers to the University of Kentucky. Beginning in fall 1991, ESD added data collection and report preparation to its responsibilities for the PGDP BMP. The goals of BMP are to (1) demonstrate that the effluent limitations established for PGDP protect and maintain the use of Little Bayou and Big Bayou creeks for growth and propagation of fish and other aquatic life, (2) characterize potential environmental impacts, (3) document the effects of pollution abatement facilities on stream biota, and (4) recommend any program improvements that would increase effluent treatability. In September 1992, a renewed Kentucky Pollutant Discharge Elimination System (KPDES) permit was issued to PGDP. The BMP for PGDP consists of three major tasks: (1) effluent and ambient toxicity monitoring, (2) bioaccumulation studies, and (3) ecological surveys of stream communities (i.e., benthic macroinvertebrates and fish). This report includes ESD activities occurring from December 1993 to December 1994, although activities conducted outside this time period are included as appropriate

Depleted uranium hexafluoride management program : data compilation for the K-25 site

International Nuclear Information System (INIS)

Hartmann, H. M.

2001-01-01

This report is a compilation of data and analyses for the K-25 site on the Oak Ridge Reservation, Oak Ridge, Tennessee. The data were collected and the analyses were done in support of the U.S. Department of Energy (DOE) 1999 Programmatic Environmental Impact Statement for Alternative Strategies for the Long-Term Management and Use of Depleted Uranium Hexafluoride (DOE/EIS-0269). The report describes the affected environment at the K-25 site and summarizes the potential environmental impacts that could result from continued cylinder storage and preparation of cylinders for shipment at the site. It is probable that the cylinders at the K-25 site will be shipped to another site for conversion. Because conversion and long-term storage of the entire inventory at the K-25 site are highly unlikely, these data are not presented in this report. DOE's preferred alternative is to begin converting the depleted uranium hexafluoride inventory as soon as possible to either uranium oxide, uranium metal, or a combination of both, while allowing for use of as much of this inventory as possible

Main results obtained in France in the development of the gaseous diffusion process for uranium isotope separation

International Nuclear Information System (INIS)

Frejacques, C.; Bilous, O.; Dixmier, J.; Massignon, D.; Plurien, P.

1958-01-01

The main problems which occur in the study of uranium isotope separation by the gaseous diffusion process, concern the development of the porous barrier, the corrosive nature of uranium hexafluoride and also the chemical engineering problems related to process design and the choice of best plant and stage characteristics. Porous barriers may be obtained by chemical attack of non porous media or by agglomeration of very fine powders. Examples of these two types of barriers are given. A whole set of measurement techniques were developed for barrier structure studies, to provide control and guidance of barrier production methods. Uranium hexafluoride reactivity and corrosive properties are the source of many difficult technological problems. A high degree of plant leak tightness must be achieved. This necessity creates a special problem in compressor bearing design. Barrier lifetime is affected by the corrosive properties of the gas, which may lead to a change of barrier structure with time. Barrier hexafluoride permeability measurements have helped to make a systematic study of this point. Finally an example of a plant flowsheet, showing stage types and arrangements and based on a minimisation of enriched product costs is also given as an illustration of some of the chemical engineering problems present. (author) [fr

Status report of the three phase 25 kA, 1.5 kW thermally switched superconducting rectifier, transformer and switches

NARCIS (Netherlands)

ten Kate, Herman H.J.; Holtslag, A.H.M.; Knoben, J.; Steffens, H.A.; van de Klundert, L.J.M.

1983-01-01

A 25 kA, 1.5 kW superconducting rectifier system has been developed. This rectifier system working like an a.c.-d.c, converter with a primary current of 35 A at 0.1Hz, will energize a 25 kA coil with an average power of 5.4 MJ/hr and a proposed energy efficiency of at least 96%. Such a highly

Pilot-scale treatability testing -- Recycle, reuse, and disposal of materials from decontamination and decommissioning activities: Soda blasting demonstration

International Nuclear Information System (INIS)

1995-08-01

The US Department of Energy (DOE) is in the process of defining the nature and magnitude of decontamination and decommissioning (D and D) obligations at its sites. With disposal costs rising and available storage facilities decreasing, DOE is exploring and implementing new waste minimizing D and D techniques. Technology demonstrations are being conducted by LMES at a DOE gaseous diffusion processing plant, the K-25 Site, in Oak Ridge, Tennessee. The gaseous diffusion process employed at Oak Ridge separated uranium-235 from uranium ore for use in atomic weapons and commercial reactors. These activities contaminated concrete and other surfaces within the plant with uranium, technetium, and other constituents. The objective of current K-25 D and D research is to make available cost-effective and energy-efficient techniques to advance remediation and waste management methods at the K-25 Site and other DOE sites. To support this objective, O'Brien and Gere tested a decontamination system on K-25 Site concrete and steel surfaces contaminated with radioactive and hazardous waste. A scouring system has been developed that removes fixed hazardous and radioactive surface contamination and minimizes residual waste. This system utilizes an abrasive sodium bicarbonate medium that is projected at contaminated surfaces. It mechanically removes surface contamination while leaving the surface intact. Blasting residuals are captured and dissolved in water and treated using physical/chemical processes. Pilot-scale testing of this soda blasting system and bench and pilot-scale treatment of the generated residuals were conducted from December 1993 to September 1994

Intrinsic fatigue crack propagation in aluminum-lithium alloys - The effect of gaseous environments

Science.gov (United States)

Piascik, Robert S.; Gangloff, Richard P.

1989-01-01

Gaseous environmental effects on intrinsic fatigue crack growth are significant for the Al-Li-Cu alloy 2090, peak aged. For both moderate Delta K-low R and low Delta K-high R regimes, crack growth rates decrease according to the environment order: purified water vapor, moist air, helium and oxygen. Gaseous environmental effects are pronounced near threshold and are not closure dominated. Here, embrittlement by low levels of H2O (ppm) supports hydrogen embrittlement and suggests that molecular transport controlled cracking, established for high Delta K-low R, is modified near threshold. Localized crack tip reaction sites or high R crack opening shape may enable the strong, environmental effect at low levels of Delta K. Similar crack growth in He and O2 eliminates the contribution of surface films to fatigue damage in alloy 2090. While 2090 and 7075 exhibit similar environmental trends, the Al-Li-Cu alloy is more resistant to intrinsic corrosion fatigue crack growth.

Accelerating proton spin diffusion in perdeuterated proteins at 100 kHz MAS

Energy Technology Data Exchange (ETDEWEB)

Wittmann, Johannes J.; Agarwal, Vipin; Hellwagner, Johannes; Lends, Alons; Cadalbert, Riccardo; Meier, Beat H., E-mail: beme@ethz.ch; Ernst, Matthias, E-mail: maer@ethz.ch [ETH Zurich, Physical Chemistry (Switzerland)

2016-12-15

Fast magic-angle spinning (>60 kHz) has many advantages but makes spin-diffusion-type proton–proton long-range polarization transfer inefficient and highly dependent on chemical-shift offset. Using 100%-HN-[{sup 2}H,{sup 13}C,{sup 15}N]-ubiquitin as a model substance, we quantify the influence of the chemical-shift difference on the spin diffusion between proton spins and compare two experiments which lead to an improved chemical-shift compensation of the transfer: rotating-frame spin diffusion and a new experiment, reverse amplitude-modulated MIRROR. Both approaches enable broadband spin diffusion, but the application of the first variant is limited due to fast spin relaxation in the rotating frame. The reverse MIRROR experiment, in contrast, is a promising candidate for the determination of structurally relevant distance restraints. The applied tailored rf-irradiation schemes allow full control over the range of recoupled chemical shifts and efficiently drive spin diffusion. Here, the relevant relaxation time is the larger longitudinal relaxation time, which leads to a higher signal-to-noise ratio in the spectra.

Experimental study on the thermochemistry of 2,5-dimethylthiophene and its acetyl derivative

International Nuclear Information System (INIS)

Ribeiro da Silva, Manuel A.V.; Santos, Ana Filipa L.O.M.

2008-01-01

This paper reports the values of the standard (p 0 = 0.1 MPa) molar enthalpies of formation, in the gaseous phase, Δ f H m 0 (g), at T = 298.15 K, of 2,5-dimethylthiophene and 3-acetyl-2,5-dimethylthiophene as (50.6 ± 1.9) kJ . mol -1 and -(123.2 ± 2.7) kJ . mol -1 , respectively. These values were derived from experimental thermodynamic parameters, namely, the standard molar enthalpies of formation, in the liquid phase, Δ f H m 0 (l), at T = 298.15 K, obtained from the standard molar enthalpies of combustion, Δ c H m 0 , measured by rotating bomb combustion calorimetry, and from the standard molar enthalpies of vaporization, Δ l g H m 0 , at T = 298.15 K, measured by high temperature Calvet microcalorimetry. The results are interpreted in terms of enthalpic increments, molecular structure and compared with structurally similar compounds

Environmental investigations at the Paducah Gaseous Diffusion Plant and surrounding area, McCracken County, Kentucky. Volume 1 - Executive summary. Final report

International Nuclear Information System (INIS)

1994-05-01

This report details the results of four studies into environmental and cultural resources on and near the Department of Energy's (DOE) Paducah Gaseous Diffusion Plant (PGDP) located in Western Kentucky in McCracken County, approximately 10 miles west of Paducah, KY. The area investigated includes the PGDP facility proper, additional area owned by DOE under use permit to the Western Kentucky Wildlife Management Area (WKWMA), area owned by the Commonwealth of Kentucky that is administered by the WKWMA, area owned by the Tennessee Valley Authority (TVA), the Metropolis Lake State Nature preserve and some privately held land. DOE requested the assistance and support of the US Army Engineer District, Nashville (CEORN) in conducting various environmental investigations of the area. The US Army Engineer Waterways Experiment Station (WES) provided technical support to the CEORN for environmental investigations of (1) wetland resources, (2) threatened or endangered species and habitats, and (3) cultural resources. A floodplain investigation was conducted by CEORN

Aerodynamic effects in isotope separation by gaseous diffusion

International Nuclear Information System (INIS)

Bert, L.A.; Prosperetti, A.; Fiocchi, R.

1978-01-01

The turbulent flow of an isotopic mixture in a porous-walled pipe is considered in the presence of suction through the wall. A simple model is formulated for the evaluation of aerodynamic effects on the separation efficiency. The predictions of the model are found to compare very favourably with experiment. In the limit of small suction velocities, results obtained by other investigators for diffusion in a turbulent steam are recovered. (author)

Self-diffusion and heterodiffusion in Zr-2.5%Nb α/β interfaces comparison with grain boundary diffusion in α-Zr

International Nuclear Information System (INIS)

Iribarren, M.J.; Dyment, F.

1991-01-01

Conventional radioactive tracer section techniques were used to make an experimental determination of diffusion parameters for Zr, Nb and Ni along the α/β boundary interfaces of Zr-2.5%Nb and comparing them with those for Zr, Nb and Co in α-Zr grain boundaries. Both determinations were made for a wide range of temperatures, including reactor working temperatures. Different materials were used for this purpose, both specially prepared alloys for diffusion experiments and part of the material from the actual pressure tubes. Different stabilizing thermal treatments were performed and results were analyzed based on the different morphologies obtained. (Author) [es

Enrichment by diffusion

International Nuclear Information System (INIS)

Mezin, M.

1976-01-01

The report presents an introduction to general basic principles of the gaseous diffusion process for the separation of uranium isotopes. Dealt with are: a) theoretical background and basic considerations of separation work and production costs, b) construction of a single separation stage and a multistage plant, c) the components of a plant and the optimization factors, d) cost factors. The text is illustrated by instructive diagrammes and flow charts. (RB) [de

The Effect of Gaseous Ozone in Infected Root Canal

Science.gov (United States)

Ajeti, Nova Nexhmije; Pustina-Krasniqi, Teuta; Apostolska, Sonja

2018-01-01

OBJECTIVES: During the treatment of chronic apical periodontitis and pulp necrosis the main role is to irrigate the root canal. AIM: The aim of this in vivo study was to irrigate with 0.9% NaCl (Natrium Chloride), 2.5 % NaOCl (Sodium Hypochlorite Solution, Sigma Aldrich - Germany) and 2% CHX (Chlorhexidine Digluconate Solution, Sigma Aldrich - Spain) combined with Gaseous Ozone (Prozone WH, Austria). MATERIAL AND METHODS: This study was realised in the University Dentistry Clinical Centre of Kosovo (UDCCK), respectively in the Department of Endodontic and Dental Pathology, Dental Branch, Faculty of Medicine, Prishtina, Kosovo. The 40 subjects involved in this study belonged to both genders, in age between 15 -65 years. The sample selection was randomised. The retroalveolar radiography for each patient was taken in the suspected tooth. As a therapeutic plan the authors decided to disinfect the root canal with the irrigants, as follows: 2.5 % NaOCl, 2 % CHX and gaseous ozone. RESULTS: The statistical analyses were based on Kruskal - Vallis test, X - test, DF = 3, r irrigants 0.9%, 2.5 % NaOCl and 2% CHX, it was concluded that the number of colonies of aerobic and anaerobic bacteria was reduced. PMID:29531611

Diffusion model of solid particles in a gaseous atmosphere. Pt. 1

International Nuclear Information System (INIS)

Fernandez Ruiz, J.L.

1987-01-01

Starting from Voinov and Garipov's lagrangian statements on the problem of dynamic evolution of bubbles in liquids, this work is trying to determine some diffusion equations of solid particles in little dense matter like gases or liquids, aiming at applying it to the tracing of matter in atmospheric diffusion and the tracing of corpuscles in liquids. All the resulting equations lead to a solution given as a tensor θ ij related to the velocity states v i defined as v i = , and to the potential from which derive. One has had in mind the factor of mutual correlation between the diffusing particles. This increases the scope of application of these equations to Chemistry and to Biomedical Sciences. (author)

Edge profiles in K shell photoabsorption spectra of gaseous hydrides of 3p elements and homologues

Science.gov (United States)

Hauko, R.; Gomilšek, J. Padežnik; Kodre, A.; Arčon, I.; Aquilanti, G.

2017-10-01

Photoabsorption spectra of gaseous hydrides of 3p elements (PH3, H2S, HCl) are measured in the energy region of photoexcitations pertaining to K edge. The analysis of the edge profile is extended to hydrides of 4p series (GeH4, AsH3, H2Se, HBr) from an earlier experiment, and to published spectra of 2p hydrides (CH4, NH3, H2O, HF) and noble gases Ar, Kr and Ne and SiH4. The edge profiles are modelled with a linear combination of lorentzian components, describing excitations to individual bound states and to continuum. Transition energies and probabilities are also calculated in the non-relativistic molecular model of the ORCA code, in good agreement with the experiment. Edge profiles in the heavier homologues are closely similar, the symmetry of the molecule governs the transitions to the lowest unoccupied orbitals. In 2p series the effect of the strong nuclear potential prevails. Transitions to higher, atomic-like levels remain very much the same as in free atoms.

Proposed sale of radioactively contaminated nickel ingots located at the Paducah Gaseous Diffusion Plant, Paducah, Kentucky

International Nuclear Information System (INIS)

1995-10-01

The U.S. Department of Energy (DOE) proposes to sell 8,500 radioactively contaminated nickel ingots (9.350 short tons), currently in open storage at the Paducah Gaseous Diffusion Plant (PGDP), to Scientific Ecology Group, Inc. (SEG) for decontamination and resale on the international market. SEG would take ownership of the ingots when they are loaded for transport by truck to its facility in Oak Ridge, Tennessee. SEG would receive approximately 200 short tons per month over approximately 48 months (an average of 180 ingots per month). The nickel decontamination process specified in SEG's technical proposal is considered the best available technology and has been demonstrated in prototype at SEG. The resultant metal for resale would have contamination levels between 0.3 and 20 becquerel per gram (Bq/g). The health hazards associated with release of the decontaminated nickel are minimal. The activity concentration of the end product would be further reduced when the nickel is combined with other metals to make stainless steel. Low-level radioactive waste from the SEG decontamination process, estimated to be approximately 382 m 3 (12,730 ft), would be shipped to a licensed commercial or DOE disposal facility. If the waste were packaged in 0.23 m 3 -(7.5 ft 3 -) capacity drums, approximately 1,500 to 1,900 drums would be transported over the 48-month contract period. Impacts from the construction of decontamination facilities and the selected site are minimal

A Population Study of Gaseous Exoplanets

Science.gov (United States)

Tsiaras, A.; Waldmann, I. P.; Zingales, T.; Rocchetto, M.; Morello, G.; Damiano, M.; Karpouzas, K.; Tinetti, G.; McKemmish, L. K.; Tennyson, J.; Yurchenko, S. N.

2018-04-01

We present here the analysis of 30 gaseous extrasolar planets, with temperatures between 600 and 2400 K and radii between 0.35 and 1.9 R Jup. The quality of the HST/WFC3 spatially scanned data combined with our specialized analysis tools allow us to study the largest and most self-consistent sample of exoplanetary transmission spectra to date and examine the collective behavior of warm and hot gaseous planets rather than isolated case studies. We define a new metric, the Atmospheric Detectability Index (ADI) to evaluate the statistical significance of an atmospheric detection and find statistically significant atmospheres in around 16 planets out of the 30 analyzed. For most of the Jupiters in our sample, we find the detectability of their atmospheres to be dependent on the planetary radius but not on the planetary mass. This indicates that planetary gravity plays a secondary role in the state of gaseous planetary atmospheres. We detect the presence of water vapour in all of the statistically detectable atmospheres, and we cannot rule out its presence in the atmospheres of the others. In addition, TiO and/or VO signatures are detected with 4σ confidence in WASP-76 b, and they are most likely present in WASP-121 b. We find no correlation between expected signal-to-noise and atmospheric detectability for most targets. This has important implications for future large-scale surveys.

Oak Ridge K-25 Site Technology Logic Diagram. Volume 1, Technology evaluation

Energy Technology Data Exchange (ETDEWEB)

Fellows, R.L. [ed.

1993-02-26

The Oak Ridge K-25 Technology Logic Diagram (TLD), a decision support tool for the K-25 Site, was developed to provide a planning document that relates environmental restoration and waste management problems at the Oak Ridge K-25 Site to potential technologies that can remediate these problems. The TLD technique identifies the research necessary to develop these technologies to a state that allows for technology transfer and application to waste management, remedial action, and decontamination and decommissioning activities. The TLD consists of four separate volumes-Vol. 1, Vol. 2, Vol. 3A, and Vol. 3B. This Volume, Volume 1 provides introductory and overview information about the TLD. Volume 2 contains logic diagrams. Volume 3 has been divided into two separate volumes to facilitate handling and use. This volume is divided into ten chapters. The first chapter is a brief introduction, and the second chapter details the technical approach of the TLD. These categories are the work activities necessary for successful decontamination and decommissioning, waste management, and remedial action of the K-25 Site. The categories are characterization, decontamination, dismantlement, robotics and automation, remedial action, and waste management. Materials disposition is addressed in Chap. 9. The final chapter contains regulatory compliance information concerning waste management, remedial action, and decontamination and decommissioning.

System Description for the K-25/K-27 D and D Project Polyurethane Foam Delivery System, East Tennessee Technology Park, Oak Ridge, Tennessee

International Nuclear Information System (INIS)

Boris, G.

2008-01-01

The Foam Delivery System used in the decontamination and decommissioning (D and D) project for the K-25/K-27 Buildings at the East Tennessee Technology Park (ETTP) is comprised of a trailer-mounted Gusmer(reg s ign) H20/35 Pro-TEC Proportioning Unit and the associated equipment to convey electrical power, air, and foam component material to the unit. This high-pressure, plural-component polyurethane foam pouring system will be used to fill process gas and non-process equipment/piping (PGE/P) within the K-25/K-27 Buildings with polyurethane foam to immobilize contaminants prior to removal. The system creates foam by mixing isocyanate and polyol resin (Resin) component materials. Currently, the project plans to utilize up to six foaming units simultaneously during peak foaming activities. Also included in this system description are the foam component material storage containers that will be used for storage of the component material drums in a staging area outside of the K-25/K-27 Buildings. The Foam Delivery System and foam component material storage enclosures (i.e., Foaming Component Protective Enclosures) used to store polymeric methylene diphenyl diisocyanate (PMDI) component material are identified as Safety Significant (SS) Structures, Systems and Components (SSC) in the Documented Safety Analysis (DSA) for the project, Documented Safety Analysis for the K-25 and K-27 Facilities at the East Tennessee Technology Park, Oak Ridge, Tennessee, DSA-ET-K-25/K-27-0001

Determination of the response function for the Portsmouth Gaseous Diffusion Plant criticality accident alarm system neutron detectors

International Nuclear Information System (INIS)

Tayloe, R.W. Jr.; Brown, A.S.; Dobelbower, M.C.; Woollard, J.E.

1997-03-01

Neutron-sensitive radiation detectors are used in the Portsmouth Gaseous Diffusion Plant's (PORTS) criticality accident alarm system (CAAS). The CAAS is composed of numerous detectors, electronics, and logic units. It uses a telemetry system to sound building evacuation horns and to provide remote alarm status in a central control facility. The ANSI Standard for a CAAS uses a free-in-air dose rate to define the detection criteria for a minimum accident-of-concern. Previously, the free-in-air absorbed dose rate from neutrons was used for determining the areal coverge of criticality detection within PORTS buildings handling fissile materials. However, the free-in-air dose rate does not accurately reflect the response of the neutron detectors in use at PORTS. Because the cost of placing additional CAAS detectors in areas of questionable coverage (based on a free-in-air absorbed dose rate) is high, the actual response function for the CAAS neutron detectors was determined. This report, which is organized into three major sections, discusses how the actual response function for the PORTS CAAS neutron detectors was determined. The CAAS neutron detectors are described in Section 2. The model of the detector system developed to facilitate calculation of the response function is discussed in Section 3. The results of the calculations, including confirmatory measurements with neutron sources, are given in Section 4

Microstructural and compositional Evolution of Compound Layers during Gaseous Nitrocarburizing

DEFF Research Database (Denmark)

Du, Hong; Somers, Marcel A.J.; Ågren, John

2000-01-01

Compound layers developed at 848 K during gaseous nitrocarburizing of iron and iron-carbon specimens were investigated for several combinations of N and C activities imposed at the specimen surface by gas mixtures of NH3, N2, CO2 and CO. The microstructural evolution of the compound layer was stu...

Detector for gaseous nuclear fission products

International Nuclear Information System (INIS)

Kobayashi, Yoshihiro; Kubo, Katsumi.

1979-01-01

Purpose: To facilitate the fabrication of a precipitator type detector, as well as improve the reliability. Constitution: Gas to be measured flown in an anode is stored in a gas processing system. By applying a voltage between the anode and the cathode, if positively charged Rb or Cs which is the daughter products of gaseous fission products are present in the gas to be measured, the daughter products are successively deposited electrostatically to the cathode. The daughter products issue beta-rays and gamma-rays to ionize the argon gas at the anode, whereby ionizing current flows between both of the electrodes. Pulses are generated from the ionizing current, and presence or absence, as well as the amount of the gaseous fission products are determined by the value recorded for the number of the pulses to thereby detect failures in the nuclear fuel elements. After the completion of the detection, the inside of the anode is evacuated and the cathode is heated to evaporate and discharge the daughter products externally. This eliminates the effects of the former detection to the succeeding detection. (Moriyama, K.)

Photosensitive Gaseous Detectors for Cryogenic Temperature Applications

CERN Document Server

Periale, L; Iacobaeus, C; Lund-Jensen, B; Picchi, P; Pietropaolo, F

2007-01-01

There are several proposals and projects today for building LXe Time Projection Chambers (TPCs) for dark matter search. An important element of these TPCs are the photomultipliers operating either inside LXe or in vapors above the liquid. We have recently demonstrated that photosensitive gaseous detectors (wire type and hole-type) can operate perfectly well until temperatures of LN2. In this paper results of systematic studies of operation of the photosensitive version of these detectors (combined with reflective or semi-transparent CsI photocathodes) in the temperature interval of 300-150 K are presented. In particular, it was demonstrated that both sealed and flushed by a gas detectors could operate at a quite stable fashion in a year/time scale. Obtained results, in particular the long-term stability of photosensitive gaseous detectors, strongly indicate that they can be cheap and simple alternatives to photomultipliers or avalanche solid-state detectors in LXe TPC applications.

Oak Ridge K-25 Site chlorinated solvent pollution prevention opportunity assessment

Energy Technology Data Exchange (ETDEWEB)

1994-08-01

A pollution prevention opportunity assessment (PPOA) was conducted at the Oak Ridge K-25 Site to identify opportunities to reduce and better manage the use of chlorinated solvents. At the K-25 Site, 67 control areas were examined for their potential use of chlorinated solvents. Of these areas, 27 were found to be using (1) chlorinated solvents for cleaning, degreasing, and lubricating; (2) laboratory standards and solvents; and (3) test medium. Current management practices encourage the identification and use of nonhazardous chemicals, including the use of chlorinated solvents. The main pollution prevention principles are source reduction and recycling, and a number of pollution prevention options based on these principles were identified and evaluated as part of this chlorinated solvent PPOA. Source reduction options evaluated for the K-25 Site include the substitution of chlorinated solvents with nonchlorinated solvents. Recycling was identified for those areas that would benefit most from the reuse of the chlorinated solvents in use. The pollution prevention options that offer the greatest opportunity for success at the K-25 Site are the implementation of substitutes at the 10 control areas using chlorinated solvents for cleaning, degreasing, and lubrication. A change in the process may be all that is needed to eliminate the use of a chlorinated solvent. Once a decision is made to implement a substitution, the information should be communicated to all shops and laboratories. Another option to consider is the installation of recycling units to recycle the large amounts of methylene chloride used in the analytical sampling procedure.

Oak Ridge K-25 Site chlorinated solvent pollution prevention opportunity assessment

International Nuclear Information System (INIS)

1994-08-01

A pollution prevention opportunity assessment (PPOA) was conducted at the Oak Ridge K-25 Site to identify opportunities to reduce and better manage the use of chlorinated solvents. At the K-25 Site, 67 control areas were examined for their potential use of chlorinated solvents. Of these areas, 27 were found to be using (1) chlorinated solvents for cleaning, degreasing, and lubricating; (2) laboratory standards and solvents; and (3) test medium. Current management practices encourage the identification and use of nonhazardous chemicals, including the use of chlorinated solvents. The main pollution prevention principles are source reduction and recycling, and a number of pollution prevention options based on these principles were identified and evaluated as part of this chlorinated solvent PPOA. Source reduction options evaluated for the K-25 Site include the substitution of chlorinated solvents with nonchlorinated solvents. Recycling was identified for those areas that would benefit most from the reuse of the chlorinated solvents in use. The pollution prevention options that offer the greatest opportunity for success at the K-25 Site are the implementation of substitutes at the 10 control areas using chlorinated solvents for cleaning, degreasing, and lubrication. A change in the process may be all that is needed to eliminate the use of a chlorinated solvent. Once a decision is made to implement a substitution, the information should be communicated to all shops and laboratories. Another option to consider is the installation of recycling units to recycle the large amounts of methylene chloride used in the analytical sampling procedure

Measuring the diffusion of Ti and Cu in low-k materials for microelectronic devices by EELS, EFTEM and EDX

International Nuclear Information System (INIS)

Barnes, J-P; Lafond, D; Guedj, C; Fayolle, M; Meininger, P; Maitrejean, S; David, T; Posseme, N; Bayle-Guillemaud, P; Chabli, Amal

2006-01-01

The need to reduce RC delay and cross talk in Cu interconnects means that ultra low-k dielectrics such as porous SiCOH are being integrated into microelectronic devices. Unfortunately porous materials lead to integration issues such as metal diffusion into the porosity of the dielectric, especially when chemical vapour deposition (CVD) methods are used for metal deposition. In our case, the copper anti-diffusion barrier used before Cu deposition is MOCVD TiN. Without an appropriate surface treatment (pore sealing) of the low-k the TiN may diffuse in the porosity. The presence of Ti or Cu in the low-k is deleterious as it can raise the dielectric constant and the leakage current. EFTEM EELS and EDX have been used to map Ti, Cu, O and C as a function of process conditions

A mathematical and numerical analysis of the Maxwell-Stefan diffusion equations

OpenAIRE

Boudin , Laurent; Grec , Bérénice; Salvarani , Francesco

2012-01-01

International audience; We consider the Maxwell-Stefan model of diffusion in a multicomponent gaseous mixture. After focusing on the main differences with the Fickian diffusion model, we study the equations governing a three-component gas mixture. We provide a qualitative and quantitative mathematical analysis of the model. The main properties of the standard explicit numerical scheme are also analyzed. We eventually include some numerical simulations pointing out the uphill diffusion phenome...

Significance of population centers as sources of gaseous and dissolved PAHs in the lower Great Lakes.

Science.gov (United States)

McDonough, Carrie A; Khairy, Mohammed A; Muir, Derek C G; Lohmann, Rainer

2014-07-15

Polyethylene passive samplers (PEs) were used to measure concentrations of gaseous and dissolved polycyclic aromatic hydrocarbons (PAHs) in the air and water throughout the lower Great Lakes during summer and fall of 2011. Atmospheric Σ15PAH concentrations ranged from 2.1 ng/m3 in Cape Vincent (NY) to 76.4 ng/m3 in downtown Cleveland (OH). Aqueous Σ18PAH concentrations ranged from 2.4 ng/L at an offshore Lake Erie site to 30.4 ng/L in Sheffield Lake (OH). Gaseous PAH concentrations correlated strongly with population within 3-40 km of the sampling site depending on the compound considered, suggesting that urban centers are a primary source of gaseous PAHs (except retene) in the lower Great Lakes region. The significance of distant population (within 20 km) versus local population (within 3 km) increased with subcooled liquid vapor pressure. Most dissolved aqueous PAHs did not correlate significantly with population, nor were they consistently related to river discharge, wastewater effluents, or precipitation. Air-water exchange calculations implied that diffusive exchange was a source of phenanthrene to surface waters, while acenaphthylene volatilized out of the lakes. Comparison of air-water fluxes with temperature suggested that the significance of urban centers as sources of dissolved PAHs via diffusive exchange may decrease in warmer months.

Method and device to measure the concentration of the various isotopes of radon in a gaseous atmosphere

Energy Technology Data Exchange (ETDEWEB)

Guelin, M; LeGac, J; Caruau, J

1990-11-30

Device to implement the method according to claim 1, wherein it is constituted of a vessel provided with an intake tube and an evacuation tube for the gaseous atmosphere and whose inside forms the closed sampling space, is subdivided into a large number of small elementary intercommunicating volumes so as to enable the taken gaseous sample to be homogenized, as well as to allow for the diffusion and the spatially homogeneous trapping of all the solid daughter products thus constituting a homogeneous emitting source for the spectrometry chain which examines this source from outside. (author). 4 figs.

Auto and hetero-diffusion along grain and interphase boundaries in α-Zr and Zr-2.5wt%Nb

International Nuclear Information System (INIS)

Dyment, F.; Iribarren, M.J.; Vieregge, K.; Herzig, C.

1993-01-01

Grain-boundary diffusion measurements made in α-Zr and interphase-boundary diffusion measurements made in the (α+β) region of Zr-2.5wt%Nb were considered together with the aim of gaining a better understanding of the behaviour of these boundaries in Zr-based materials which are relevant for the nuclear industry. When comparing the total set of data it turns out that, from the diffusion point of view, both types of boundaries provide similar short-circuit diffusion paths. (orig.)

Structural inspection and wind analysis of redwood cooling towers at the Portsmouth Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Chung, T.; Solack, T.; Hortel, J.

1991-01-01

As part of the plant upgrade program, structural analyses and field inspections were performed on four redwood cooling towers at the DOE Portsmouth gaseous diffusion plant located in Piketon, Ohio. The cooling towers are categorized as important hazard facilities. The loadings are derived from UCRL-15910 according to the pertinent hazard category. In addition to the seismic and wind loadings, the wood cooling towers are constantly subject to adverse environmental effects such as elevated temperature, chemical attack, icing and snow load, and motor vibrations. A thorough structural evaluation for all load combinations was performed for each of the cooling towers based on the structural code requirements of the Cooling Tower Institute and National Forest Products Association. Most stress criteria are unique for the redwood material. This evaluation was performed using finite element techniques on the global structural integrity and supplemented by hand calculations on the individual connection joints. Overloaded wood structural members and joints are identified by the analysis. The rectangular tower structure sits on a concrete basin that span across 60 ft by 200 ft. A major part of the cooling towers upgrading program involved field inspections of the individual cells of each tower. The primary purpose of these inspections was to identify any existing structural damage or deficiencies such as failed members, degraded wood, and deficiencies resulting from poor construction practice. Inspection of 40 cells identified some generic deficiencies that mostly are consistent with the analytical finding. Based on the analysis, some effective but inexpensive upgrading techniques were developed and recommended to bring the cooling towers into compliance with current DOE requirements

Routine environmental audit of the K-25 Site, Oak Ridge, Tennessee

Energy Technology Data Exchange (ETDEWEB)

1994-02-01

This report documents the results of the Routine Environmental Audit of the K-25 Site in Oak Ridge, Tennessee, conducted February 14 through February 25, 1994, by the US Department of Energy`s (DOE`s) Office of Environmental Audit (EH-24) located within the Office of Environment, Safety and Health (EH). The Routine Environmental Audit for the K-25 site was conducted as an environmental management assessment, supported through reviews of the Waste Management Program and the Decontamination and Decommissioning Program. The assessment was conducted jointly with, and built upon, the results provided by the ``DOE Oak Ridge Operations Office Environment, Safety, health and Quality Assurance Appraisal at the K-25 Site.`` DOE 5482.1B, ``Environment, Safety and Health Appraisal Program,`` established the mission of EH-24 to provide comprehensive, independent oversight of Department-wide environmental programs on behalf of the Secretary of Energy. The purpose of this assessment is to provide the Secretary of Energy and senior DOE managers with concise independent information as part of DOE`s continuing effort to improve environmental program performance. The ultimate goal of EH-24 is enhancement of environmental protection and the minimization of risk to public health and the environment. The routine environmental audit is one method by which EH-24 accomplishes its mission, utilizing systematic and periodic evaluations of the Department`s environmental programs within line organizations.

Routine environmental audit of the K-25 Site, Oak Ridge, Tennessee

International Nuclear Information System (INIS)

1994-02-01

This report documents the results of the Routine Environmental Audit of the K-25 Site in Oak Ridge, Tennessee, conducted February 14 through February 25, 1994, by the US Department of Energy's (DOE's) Office of Environmental Audit (EH-24) located within the Office of Environment, Safety and Health (EH). The Routine Environmental Audit for the K-25 site was conducted as an environmental management assessment, supported through reviews of the Waste Management Program and the Decontamination and Decommissioning Program. The assessment was conducted jointly with, and built upon, the results provided by the ''DOE Oak Ridge Operations Office Environment, Safety, health and Quality Assurance Appraisal at the K-25 Site.'' DOE 5482.1B, ''Environment, Safety and Health Appraisal Program,'' established the mission of EH-24 to provide comprehensive, independent oversight of Department-wide environmental programs on behalf of the Secretary of Energy. The purpose of this assessment is to provide the Secretary of Energy and senior DOE managers with concise independent information as part of DOE's continuing effort to improve environmental program performance. The ultimate goal of EH-24 is enhancement of environmental protection and the minimization of risk to public health and the environment. The routine environmental audit is one method by which EH-24 accomplishes its mission, utilizing systematic and periodic evaluations of the Department's environmental programs within line organizations

Gaseous Matter

CERN Document Server

Angelo, Joseph A

2011-01-01

aseous Matter focuses on the many important discoveries that led to the scientific interpretation of matter in the gaseous state. This new, full-color resource describes the basic characteristics and properties of several important gases, including air, hydrogen, helium, oxygen, and nitrogen. The nature and scope of the science of fluids is discussed in great detail, highlighting the most important scientific principles upon which the field is based. Chapters include:. Gaseous Matter An Initial Perspective. Physical Characteristics of Gases. The Rise of the Science of Gases. Kinetic Theory of

Rancho Seco building wake effects on atmospheric diffusion

International Nuclear Information System (INIS)

Start, G.E.; Cate, J.H.; Dickson, C.R.; Ricks, N.R.; Ackerman, G.R.; Sagendorf, J.F.

1977-11-01

A series of 23 paired gaseous tracer releases at the Rancho Seco Nuclear Power Station in 1975 was the third of several tests designed to investigate the diffusion characteristics of the atmosphere under conditions of low windspeed and temperature inversion. This test also evaluated the effects of flow around buildings upon dilution of pollutants. Gaseous tracers were laterally dispersed about six times more than the expected amounts from Pasquill--Gifford curves of sigma-y. Most of this increase could be related to observed variance of the horizontal wind direction (meandering). For ground-level releases the effective sigma-z values were 16 times greater than the corresponding values from the Pasquill--Gifford curves. Measured ground-level axial concentrations were about 75 times smaller than predicted by the Gaussian diffusion equation for a ground-level release when Pasquill--Gifford values of sigma-y and sigma-z were used

Probing Into the Atmosphere of the Young Exoplanet K2-25b

Science.gov (United States)

Chia Thao, Pa; Mann, Andrew

2018-01-01

Planets are most transformative during their early life, yet there remains little research on this developmental stage. In order to construct a more accurate picture of the diversity and evolution of planetary atmospheres, we present Spitzer infrared photometry of five transits both in 3.6 μm and 4.5 μm bands of the young exoplanet, K2-25b (650-800 Myr). To correct for the intra-pixel photometric response, we interpolated high-resolution sensitivity maps. Light curves were then created using a transit model and an MCMC framework to find the planet parameters in each wavelength. In comparison to atmospheric theoretical models, we find K2-25b unlikely to have a solar-metallicity atmosphere. However, observed through a full transmission spectrum, K2-25b is consistent with either a high-metallicity atmosphere or a cloudy/hazy layer. Further HST data would provide significantly more detail on the structure of the atmosphere. In a future project, we plan to apply this same method to a younger planet, K2-33b (11 Myr), to determine if cloudy/hazy atmospheres are primordial.

Technology needs for environmental restoration remedial action. Environmental Restoration Program

Energy Technology Data Exchange (ETDEWEB)

Watson, J.S.

1992-11-01

This report summarizes the current view of the most important technology needs for the US Department of Energy (DOE) facilities operated by Martin Marietta Energy Systems, Inc. These facilities are the Oak Ridge National Laboratory, the Oak Ridge K-25 Site, the Oak Ridge Y-12 Plant, the Paducah Gaseous Diffusion Plant, and the Portsmouth Gaseous Diffusion Plant. The sources of information used in this assessment were a survey of selected representatives of the Environmental Restoration (ER) programs at each facility, results from a questionnaire distributed by Geotech CWM, Inc., for DOE, and associated discussions with individuals from each facility. This is not a final assessment, but a brief look at an ongoing assessment; the needs will change as the plans for restoration change and, it is hoped, as some technical problems are solved through successful development programs.

Technology needs for environmental restoration remedial action

Energy Technology Data Exchange (ETDEWEB)

Watson, J.S.

1992-11-01

This report summarizes the current view of the most important technology needs for the US Department of Energy (DOE) facilities operated by Martin Marietta Energy Systems, Inc. These facilities are the Oak Ridge National Laboratory, the Oak Ridge K-25 Site, the Oak Ridge Y-12 Plant, the Paducah Gaseous Diffusion Plant, and the Portsmouth Gaseous Diffusion Plant. The sources of information used in this assessment were a survey of selected representatives of the Environmental Restoration (ER) programs at each facility, results from a questionnaire distributed by Geotech CWM, Inc., for DOE, and associated discussions with individuals from each facility. This is not a final assessment, but a brief look at an ongoing assessment; the needs will change as the plans for restoration change and, it is hoped, as some technical problems are solved through successful development programs.

Technology needs for environmental restoration remedial action

International Nuclear Information System (INIS)

Watson, J.S.

1992-11-01

This report summarizes the current view of the most important technology needs for the US Department of Energy (DOE) facilities operated by Martin Marietta Energy Systems, Inc. These facilities are the Oak Ridge National Laboratory, the Oak Ridge K-25 Site, the Oak Ridge Y-12 Plant, the Paducah Gaseous Diffusion Plant, and the Portsmouth Gaseous Diffusion Plant. The sources of information used in this assessment were a survey of selected representatives of the Environmental Restoration (ER) programs at each facility, results from a questionnaire distributed by Geotech CWM, Inc., for DOE, and associated discussions with individuals from each facility. This is not a final assessment, but a brief look at an ongoing assessment; the needs will change as the plans for restoration change and, it is hoped, as some technical problems are solved through successful development programs

Oak Ridge K-25 Site Technology Logic Diagram. Volume 2, Technology Logic Diagrams

Energy Technology Data Exchange (ETDEWEB)

Fellows, R.L. [ed.

1993-02-26

The Oak Ridge K-25 Technology Logic Diagram (TLD), a decision support tool for the K-25 Site, was developed to provide a planning document that relates envirorunental restoration and waste management problems at the Oak Ridge K-25 Site to potential technologies that can remediate these problems. The TLD technique identifies the research necessary to develop these technologies to a state that allows for technology transfer and application to waste management, remedial action, and decontamination and decommissioning activities. The TLD consists of four separate volumes-Vol. 1, Vol. 2, Vol. 3A, and Vol. 3B. Volume 1 provides introductory and overview information about the TLD. This volume, Volume 2, contains logic diagrams with an index. Volume 3 has been divided into two separate volumes to facilitate handling and use.

Thermodynamic properties of cesium in the gaseous phase

International Nuclear Information System (INIS)

Vargaftik, N.B.; Voljak, L.D.; Stepanov, V.G.

1985-01-01

Tables of the thermodynamic properties of caesium in the gaseous phase are presented for a wide range of temperature and pressure. The thermodynamic properties include: enthalpy, entropy, specific heat, specific volume, sound velocity and compressibility factor. The values have been calculated from pressure-volume-temperature measurements by various authors. Experimental apparatus to determine these measurements is described, together with an outline of the method employed to process the results, and the error estimates. (U.K.)

Isotope exchange between gaseous hydrogen and uranium hydride powder

International Nuclear Information System (INIS)

Shugard, Andrew D.; Buffleben, George M.; Johnson, Terry A.; Robinson, David B.

2014-01-01

Highlights: • Isotope exchange between hydrogen gas and uranium hydride powder can be rapid and reversible. • Gas–solid exchange rate is controlled by transport within ∼0.7 μm hydride particles. • Gas chromatographic separation of hydrogen isotopes using uranium hydride is feasible. - Abstract: Isotope exchange between gaseous hydrogen and solid uranium hydride has been studied by flowing hydrogen (deuterium) gas through packed powder beds of uranium deuteride (hydride). We used a residual gas analyzer system to perform real-time analysis of the effluent gas composition. We also developed an exchange and transport model and, by fitting it to the experimental data, extracted kinetic parameters for the isotope exchange reaction. Our results suggest that, from approximately 70 to 700 kPa and 25 to 400 °C, the gas-to-solid exchange rate is controlled by hydrogen and deuterium transport within the ∼0.7 μm diameter uranium hydride particles. We use our kinetic parameters to show that gas chromatographic separation of hydrogen and deuterium using uranium hydride could be feasible

Biological Monitoring and Abatement Program for the Oak Ridge K-25 Site

International Nuclear Information System (INIS)

Kszos, L.A.; Adams, S.M.; Ashwood, T.L.; Blaylock, B.G.; Greeley, M.S.; Loar, J.M.; Peterson, M.J.; Ryon, M.G.; Smith, J.G.; Southworth, G.R.; Hinzman, R.L.; Shoemaker, B.A.

1993-04-01

A proposed Biological Monitoring and Abatement Program (BMAP) for the Oak Ridge K-25 Site was prepared in December 1992 as required by the renewed National Pollutant Discharge Elimination System permit that was issued on October 1, 1992. The proposed BMAP is based on results of biological monitoring conducted from 1986 to 1992 and discussions held on November 12, 1992, between staff of Martin Marietta Energy Systems, Inc. (Oak Ridge National Laboratory and the K-25 Site), and the Tennessee Department of Environment and Conservation, Department of Energy Oversight Division. The proposed BMAP consists of four tasks that reflect different but complementary approaches to evaluating the effects of K-25 Site effluents on the ecological integrity of Mitchell Branch, Poplar Creek, and the Poplar Creek embayment of the Clinch River. These tasks include (1) ambient toxicity monitoring, (2) bioaccumulation monitoring, (3) assessment of fish health, and (4) instream monitoring of biological communities. This overall BMAP plan combines established protocols with current biological monitoring techniques to assess environmental compliance and quantify ecological recovery. The BMAP will also determine whether the effluent limits established for the K-25 Site protect the designated use of the receiving streams (Mitchell Branch, Poplar Creek, and Clinch River) for growth and propagation of fish and other aquatic life. Results obtained from this biological monitoring program will also be used to document the ecological effects (and effectiveness) of remedial actions

Biological Monitoring and Abatement Program for the Oak Ridge K-25 Site

Energy Technology Data Exchange (ETDEWEB)

Kszos, L.A.; Adams, S.M.; Ashwood, T.L.; Blaylock, B.G.; Greeley, M.S.; Loar, J.M.; Peterson, M.J.; Ryon, M.G.; Smith, J.G.; Southworth, G.R. (Oak Ridge National Lab., TN (United States)); Hinzman, R.L. (Oak Ridge Research Inst., TN (United States)); Shoemaker, B.A. (Oak Ridge K-25 Site, TN (United States))

1993-04-01

A proposed Biological Monitoring and Abatement Program (BMAP) for the Oak Ridge K-25 Site was prepared in December 1992 as required by the renewed National Pollutant Discharge Elimination System permit that was issued on October 1, 1992. The proposed BMAP is based on results of biological monitoring conducted from 1986 to 1992 and discussions held on November 12, 1992, between staff of Martin Marietta Energy Systems, Inc. (Oak Ridge National Laboratory and the K-25 Site), and the Tennessee Department of Environment and Conservation, Department of Energy Oversight Division. The proposed BMAP consists of four tasks that reflect different but complementary approaches to evaluating the effects of K-25 Site effluents on the ecological integrity of Mitchell Branch, Poplar Creek, and the Poplar Creek embayment of the Clinch River. These tasks include (1) ambient toxicity monitoring, (2) bioaccumulation monitoring, (3) assessment of fish health, and (4) instream monitoring of biological communities. This overall BMAP plan combines established protocols with current biological monitoring techniques to assess environmental compliance and quantify ecological recovery. The BMAP will also determine whether the effluent limits established for the K-25 Site protect the designated use of the receiving streams (Mitchell Branch, Poplar Creek, and Clinch River) for growth and propagation of fish and other aquatic life. Results obtained from this biological monitoring program will also be used to document the ecological effects (and effectiveness) of remedial actions.

Field evaluation of a horizontal well recirculation system for groundwater treatment: Pilot test at the Clean Test Site Portsmouth Gaseous Diffusion Plant, Piketon, Ohio

International Nuclear Information System (INIS)

Muck, M.T.; Kearl, P.M.; Siegrist, R.L.

1998-01-01

This report presents the results of field testing a horizontal well recirculation system at the Portsmouth Gaseous Diffusion Plant (PORTS). The recirculation system uses a pair of horizontal wells, one for groundwater extraction and treatment and the other for reinjection of treated groundwater, to set up a recirculation flow field. The induced flow field from the injection well to the extraction well establishes a sweeping action for the removal and treatment of groundwater contaminants. The overall purpose of this project is to study treatment of mixed groundwater contaminants that occur in a thin water-bearing zone not easily targeted by traditional vertical wells. The project involves several research elements, including treatment-process evaluation, hydrodynamic flow and transport modeling, pilot testing at an uncontaminated site, and pilot testing at a contaminated site. The results of the pilot test at an uncontaminated site, the Clean Test Site (CTS), are presented in this report

First Measurements of Ambient Total Gaseous Mercury (TGM at the EvK2CNR Pyramid Observatory in Nepal

Directory of Open Access Journals (Sweden)

Gratz L. E.

2013-04-01

Full Text Available As part of the Global Mercury Observation System (GMOS project, a global-scale network of ground-based atmospheric monitoring sites is being developed with the objective of expanding the global coverage of atmospheric mercury (Hg measurements and improving our understanding of global atmospheric Hg transport. An important addition to the GMOS monitorng network has been the high altitude EvK2CNR Pyramid Observatory, located at an elevation of 5,050 meters a.s.l. in the eastern Himalaya Mountains of Nepal. Monitoring of total gaseous mercury (TGM using the Tekran 2537A Mercury Vapor Analyzer began at the EvK2CNR Pyramid Observatory in November 2011. From 17 November 2011 to 23 April 2012, the mean concentration of TGM at the Pyramid was 1.2 ng m−3. A range of concentrations from 0.7 to 2.6 ng m−3 has been observed. These are the first reported measurements of atmospheric Hg in Nepal, and currently this is the highest altitude monitoring station for atmospheric Hg in the world. It is anticipated that these high quality measurements, in combination with the other continuous atmospheric measurments being collected at the Pyramid station, will help to further our understanding of Hg concentrations in the free troposphere and the transport of atmospheric Hg on the global scale.

Prediction of external corrosion for steel cylinders

International Nuclear Information System (INIS)

Lyon, B.F.

1997-02-01

The US Department of Energy (DOE) currently manages the UF 6 Cylinder Program (the program). The program was formed to address the depleted-uranium hexafluoride (UF 6 ) stored in approximately 50,000 carbon steel cylinders. The cylinders are located at three DOE sites: the K-25 site (K-25) at Oak Ridge, Tennessee; the Paducah Gaseous Diffusion Plant (PGDP) in Paducah, Kentucky, and the Portsmouth Gaseous Diffusion Plant (PORTS) in Portsmouth, Ohio. The System Requirements Document (SRD) (LMES 1996a) delineates the requirements of the program. The appropriate actions needed to fulfill these requirements are then specified within the System Engineering Management Plan (SEMP) (LMES 1996b). The report presented herein documents activities that in whole or in part satisfy specific requirements and actions stated in the UF 6 Cylinder Program SRD and SEMP with respect to forecasting cylinder conditions. The wall thickness projections made in this report are based on the assumption that the corrosion trends noted will continue. Some activities planned may substantially reduce the rate of corrosion, in which case the results presented here are conservative. The results presented here are intended to supersede those presented previously, as the quality of several of the datasets has improved

Biological Monitoring and Abatement Program for the Oak Ridge K-25 Site

International Nuclear Information System (INIS)

Kszos, L.A.; Adams, S.M.; Ashwood, T.L.; Blaylock, B.G.; Greeley, M.S.; Loar, J.M.; Peterson, M.J.; Ryon, M.G.; Smith, J.G.; Southworth, G.R.; Shoemaker, B.A.; Hinzman, R.L.

1993-02-01

A proposed Biological Monitoring and Abatement Program (BMAP) for the Oak Ridge K-25 Site was prepared in December 1992 as required by the renewed National Pollutant Discharge Elimination System permit that was issued on October 1, 1992. The proposed BMAP consists of four tasks that reflect different but complementary approaches to evaluating the effects of K-25 Site effluents on the ecological integrity of Mitchell Branch, Poplar Creek, and the Poplar Creek embayment of the Clinch River. These tasks include (1) ambient toxicity monitoring, (2) bioaccumulation monitoring, (3) assessment of fish health, and (4) instream monitoring of biological communities. This overall BMAP plan combines established protocols with current biological monitoring techniques to assess environmental compliance and quantify ecological recovery. The BMAP will also determine whether the effluent limits established for the K-25 Site protect the designated use of the receiving streams (Mitchell Branch, Poplar Creek, and Clinch River) for growth and propagation of fish and other aquatic life. Results obtained from this biological monitoring program will also be used to document the ecological effects (and effectiveness) of remedial actions

Biological Monitoring and Abatement Program for the Oak Ridge K-25 Site

Energy Technology Data Exchange (ETDEWEB)

Kszos, L. A.; Adams, S. M.; Ashwood, T. L.; Blaylock, B. G.; Greeley, M. S.; Loar, J. M.; Peterson, M. J.; Ryon, M. G.; Smith, J. G.; Southworth, G. R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Environmental Sciences Div.; Shoemaker, B. A. [Oak Ridge K-25 Site, TN (United States); Hinzman, R. L. [Oak Ridge Research Inst., TN (United States)

1993-02-01

A proposed Biological Monitoring and Abatement Program (BMAP) for the Oak Ridge K-25 Site was prepared in December 1992 as required by the renewed National Pollutant Discharge Elimination System permit that was issued on October 1, 1992. The proposed BMAP consists of four tasks that reflect different but complementary approaches to evaluating the effects of K-25 Site effluents on the ecological integrity of Mitchell Branch, Poplar Creek, and the Poplar Creek embayment of the Clinch River. These tasks include (1) ambient toxicity monitoring, (2) bioaccumulation monitoring, (3) assessment of fish health, and (4) instream monitoring of biological communities. This overall BMAP plan combines established protocols with current biological monitoring techniques to assess environmental compliance and quantify ecological recovery. The BMAP will also determine whether the effluent limits established for the K-25 Site protect the designated use of the receiving streams (Mitchell Branch, Poplar Creek, and Clinch River) for growth and propagation of fish and other aquatic life. Results obtained from this biological monitoring program will also be used to document the ecological effects (and effectiveness) of remedial actions.

Inter- and intra-annular proton exchange in gaseous benzylbenzenium ions (protonated diphenylmethane)

OpenAIRE

Kuck, Dietmar; Bäther, Wolfgang

1986-01-01

Two distinct proton exchange reactions occur in metastable gaseous benzylbenzenium ions, generated by isobutane chemical ionization of diphenylmethane and four deuterium-labelled analogues. Whereas the proton ring-walk at the benzenium moiety is fast giving rise to a completely random intraannular proton exchange, the interannular proton exchange is surprisingly slow and competes with the elimination of benzene. A kinetic isotope effect of kH/kD= 5 has been determined for the interannular pro...

Removal ratio of gaseous toluene and xylene transported from air to root zone via the stem by indoor plants.

Science.gov (United States)

Kim, K J; Kim, H J; Khalekuzzaman, M; Yoo, E H; Jung, H H; Jang, H S

2016-04-01

This work was designed to investigate the removal efficiency as well as the ratios of toluene and xylene transported from air to root zone via the stem and by direct diffusion from the air into the medium. Indoor plants (Schefflera actinophylla and Ficus benghalensis) were placed in a sealed test chamber. Shoot or root zone were sealed with a Teflon bag, and gaseous toluene and xylene were exposed. Removal efficiency of toluene and total xylene (m, p, o) was 13.3 and 7.0 μg·m(-3)·m(-2) leaf area over a 24-h period in S. actinophylla, and was 13.0 and 7.3 μg·m(-3)·m(-2) leaf area in F. benghalensis. Gaseous toluene and xylene in a chamber were absorbed through leaf and transported via the stem, and finally reached to root zone, and also transported by direct diffusion from the air into the medium. Toluene and xylene transported via the stem was decreased with time after exposure. Xylene transported via the stem was higher than that by direct diffusion from the air into the medium over a 24-h period. The ratios of toluene transported via the stem versus direct diffusion from the air into the medium were 46.3 and 53.7% in S. actinophylla, and 46.9 and 53.1% in F. benghalensis, for an average of 47 and 53% for both species. The ratios of m,p-xylene transported over 3 to 9 h via the stem versus direct diffusion from the air into the medium was 58.5 and 41.5% in S. actinophylla, and 60.7 and 39.3% in F. benghalensis, for an average of 60 and 40% for both species, whereas the ratios of o-xylene transported via the stem versus direct diffusion from the air into the medium were 61 and 39%. Both S. actinophylla and F. benghalensis removed toluene and xylene from the air. The ratios of toluene and xylene transported from air to root zone via the stem were 47 and 60 %, respectively. This result suggests that root zone is a significant contributor to gaseous toluene and xylene removal, and transported via the stem plays an important role in this process.

Theory of the separation of a gaseous mixture by diffusion through a porous wall (1962); Theorie de la separation d'un melange gazeux par diffusion a travers une paroi poreuse (1962)

Energy Technology Data Exchange (ETDEWEB)

Breton, J P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1962-06-15

The present-day theories of separation by gaseous diffusion (Present and de BETHUNE, KYNCH, BOSANQUET) are all based on the same model in which the pores are cylindrical capillaries. In the theory presented here, we substitute for this model that of a disordered and isotropic bed of identical spheres, which describes more accurately most of the porous media. We take as our starting point DERIAGUINE and BAKANOV'S permeability theory, which expresses the flow of a simple gas in such a bed when the latter is of high porosity. We first generalise this theory in the case of medium and low porosities; then, we go on to a mixture of two gases, from which we deduce our separation theory. Finally we compare our results with those of Present and de BETHUNE. (author) [French] Les theories actuelles de la separation par diffusion gazeuse (PRESENT et de BETHUNE, KYNCH, BOSANQUET) reposent toutes sur le modele des pores capillaires cylindriques. Dans la theorie presentee ici, nous substituons a ce modele celui d'un empilement desordonne et isotropes de spheres identiques, qui decrit plus correctement la plupart des milieux poreux. Nous partons de la theorie de la permeabilite de DERIAGUINE et BAKANOV, qui exprime l'ecoulement d'un gaz simple dans un tel empilement dans le cas ou la porosite en est elevee. Nous generalisons d'abord cette theorie du cas des porosites moyennes ou faibles, puis, passant a un melange de deux gaz, nous en deduisons une theorie de la separation. Pour terminer, nous comparons nos resultats a ceux de PRESENT et de BETHUNE. (auteur)

Increased Suicide Risk among Workers following Toxic Metal Exposure at the Paducah Gaseous Diffusion Plant From 1952 to 2003: A Cohort Study

Directory of Open Access Journals (Sweden)

LW Figgs

2011-09-01

Full Text Available Background: Suicide is a problem worldwide and occupation is an important risk factor. In the last decade, 55 200 deaths in the US were attributed to occupational risk factors. Objective: To determine if toxic metal exposure was associated with suicide risk among Paducah gaseous diffusion plant (PGDP workers. Methods: We assembled a cohort of 6820 nuclear industry workers employed from 1952 to 2003. A job-specific exposure matrix (JEM was used to determine metal exposure likelihood. Uranium exposure was also assessed by urinalysis. All suicide/self-injury International Classification for Disease (ICD codes were used to identify suicides. Standardized mortality ratios (SMR, odds ratios (OR, and hazard ratios (HR were used to estimate suicide risk. Results: PGDP suicide victims typically were younger white men. Within exposure likelihood categories, several suicide SMRs were typically elevated for several metals. Only beryllium exposure likelihood was associated with an increased HR. Uranium urine concentration was associated with an elevated suicide risk after stratification by urinalysis frequency. Conclusion: Suicide risk is associated with uranium exposure.

Simulation of gas hydrogen diffusion through partially water saturated mono-modal materials

International Nuclear Information System (INIS)

Boher, C.; Lorente, S.; Frizon, F.; Bart, F.

2012-01-01

Concerning the disposal of nuclear wastes, it is important to design concrete envelopes with pore networks that allow the diffusion of hydrogen towards the outside. This work documents the relationship between geo-polymers, which are materials with a quasi mono-modal pore network, and their gaseous diffusivity capacities. Using a mono-modal material allows studying a specific pore size contribution to gaseous diffusion. The pore network is characterized by mercury porosimetry. These experimental results are used as data in a model named MOHYCAN. The modeling work consists of creating a virtual pore network. Then, water layers are deposited in this network to simulate variable water saturation levels. Finally hydrogen is transported through the virtual network using a combination of ordinary diffusion and Knudsen diffusion. MOHYCAN calculates the hydrogen diffusion coefficient for water saturation degree from 0% to 100%. The impacts of the pore network arrangement or the pore network discretization have been studied. The results are, for a quasi mono-modal material: -) the diffusion coefficient is not sensitive to different virtual pore network arrangement; -) the diffusion coefficient values have a sharp drop at specific water saturation (this is due to the water saturation of the main and unique pore family); -) a 2 pores family based model is sufficient to represent the pore network. Theses observations will not be valid if we consider a material with a large pore size distribution, like cementitious materials

The 25 kW resonant dc/dc power converter

Science.gov (United States)

Robson, R. R.

1983-01-01

The feasibility of processing 25-kW of power with a single, transistorized, series resonant converter stage was demonstrated by the successful design, development, fabrication, and testing of such a device which employs four Westinghouse D7ST transistors in a full-bridge configuration and operates from a 250-to-350 Vdc input bus. The unit has an overall worst-case efficiency of 93.5% at its full rated output of 1000 V and 25 A dc. A solid-state dc input circuit breaker and output-transient-current limiters are included in and integrated into the design. Full circuit details of the converter are presented along with the test data.

The thermodynamic functions of gaseous actinide elements

International Nuclear Information System (INIS)

Rand, M.H.

1979-01-01

The actinide gases have large number of unobserved energy states - up to 3 x 10 6 for Pu(g) - which could contribute to the partition function and its derivatives, from which the thermal functions of these gases are calculated. Existing compilations have simply ignored these levels. By making reasonable assumptions as to the distribution of these energy states, their effect on the functions can be calculated. It is concluded that the existing compilations will be inadequate above approximately 2000K. The effect is particularly marked on the heat capacity. For example, when unobserved levels for Pu(g) are included, the heat capacity of Pu(g) reaches a maximum value of more than 12R at 3200K. Similar considerations will apply to the gaseous actinide ions. (orig.) [de

Gaseous waste processing facility

International Nuclear Information System (INIS)

Konno, Masanobu; Uchiyama, Yoshio; Suzuki, Kunihiko; Kimura, Masahiro; Kawabe, Ken-ichi.

1992-01-01

Gaseous waste recombiners 'A' and 'B' are connected in series and three-way valves are disposed at the upstream and the downstream of the recombiners A and B, and bypass lines are disposed to the recombiners A and B, respectively. An opening/closing controller for the three-way valves is interlocked with a hydrogen densitometer disposed to a hydrogen injection line. Hydrogen gas and oxygen gas generated by radiolysis in the reactor are extracted from a main condenser and caused to flow into a gaseous waste processing system. Gaseous wastes are introduced together with overheated steams to the recombiner A upon injection of hydrogen. Both of the bypass lines of the recombiners A and B are closed, and recombining reaction for the increased hydrogen gas is processed by the recombiners A and B connected in series. In an operation mode not conducting hydrogen injection, it is passed through the bypass line of the recombiner A and processed by the recombiner B. With such procedures, the increase of gaseous wastes due to hydrogen injection can be coped with existent facilities. (I.N.)

Decommissioning of the gaseous diffusion plant at BNFL Capenhurst

International Nuclear Information System (INIS)

Baxter, S.G.; Bradbury, P.

1992-01-01

The history of the on-going dismantling and disposal program for the Capenhurst Diffusion Plant is described. Reference is made to the scale of the project and to the special techniques developed, particularly in the areas of size reduction, decontamination and protection of personnel and the environment. When the project is successfully concluded by the end of 1993 over 99% of the materials of construction of the plant will have been recycled to the environment as clean material. (author)

Detection of gaseous fission products in water - a method of monitoring fuel sheathing failures

Energy Technology Data Exchange (ETDEWEB)

Tunnicliffe, P. R.; Whittier, A. C.

1959-05-15

The gaseous activities stripped from samples of effluent coolant from the NRU fuel elements tested in the central thimble of the NRX reactor (NRU loop) and from the NRX main effluent have been investigated. The activities obtained from the NRU loop can be attributed to gaseous fission products only. Design data have been obtained for a 'Gaseous Fission Product Monitor' to be installed for use with the NRU reactor. It is expected that this monitor will have high sensitivity to activity indicative of an incipient fuel element sheath failure. No qualitative determination of the various gaseous activities obtained from the NRX effluent has been made. A strong component of 25 {+-}1 seconds half-life is not consistent with O-19. Limited information concerning sheath failures in NRX was obtained. Of six failures observed in parallel with the installed delayed neutron monitors, three of these gave pre-warnings and in each case the gaseous fission product monitor showed a substantially greater sensitivity. An experiment in which small samples of uranium, inserted into the NRX reactor, could be exposed at will to a stream of water showed the behaviour of the two types of monitors to be similar. However, a number of signals were detected only by the gaseous fission product monitor. These can be attributed to its sensitivity to relatively long lived fission products. (author)

Quantum chemical approach for condensed-phase thermochemistry (IV): Solubility of gaseous molecules

Science.gov (United States)

Ishikawa, Atsushi; Kamata, Masahiro; Nakai, Hiromi

2016-07-01

The harmonic solvation model (HSM) was applied to the solvation of gaseous molecules and compared to a procedure based on the ideal gas model (IGM). Examination of 25 molecules showed that (i) the accuracy of ΔGsolv was similar for both methods, but the HSM shows advantages for calculating ΔHsolv and TΔSsolv; (ii) TΔSsolv contributes more than ΔHsolv to ΔGsolv in the HSM, i.e. the solvation of gaseous molecules is entropy-driven, which agrees well with experimental understanding (the IGM does not show this); (iii) the temperature dependence of Henry's law coefficient was correctly reproduced with the HSM.

Gaseous products generated by radiation degradation of N,N-diethylhydroxylamine aqueous solution

International Nuclear Information System (INIS)

Wang Jinhua; Wang Shengxiu; Bao Borong; Li Zhen; Li Chun; Zheng Weifang; Zhang Shengdong

2008-01-01

In this paper, gaseous products generated by radiation degradation of N,N-diethylhydroxylamine (DEHA) in aqueous solution are studied. The results show that by 10-1000 kGy irradiation of the solution in DEHA concentration of 0.1-0.5 mol·L -1 , the gaseous products were mainly hydrogen, methane, ethane and ethene. The volume fraction of hydrogen did not change much with different concentrations of DEHA. The volume fraction of methane and ethane decreased, but that of ethene increased, with increasing DEHA concentration. The volume fraction of hydrogen, methane and ethane increased with the dose. The relationship of the volume fraction of ethene with the dose had something to do with the DEHA concentration. (authors)

Data evaluation technical memorandum on the K-1407C Retention Basin at the Oak Ridge K-25 Site, Oak Ridge, Tennessee

International Nuclear Information System (INIS)

Beal, D.; Bock, J.; Hatmaker, T.; Zolyniak, J.; Goddard, P.; Kucsmas, D.

1991-10-01

The K-1407-C Retention Basin was a surface impoundment at the Oak Ridge K-25 Site. The basin was used primarily for storing potassium hydroxide scrubber sludge generated at the K-25 Site. In addition, from 1960 to 1973, metal hydroxide sludges that were removed from the K-1407-B Holding Pond were discharged to the K-1407-C Retention Basin. The sludge in the K-1407-B Pond contained discharge from the K-1420 Decontamination and Uranium Recovery, the K-1501 Steam Plant, the K-1413 Laboratory, and the K-1401 Maintenance Building. Radioactive material is also present in the K-1407-C Retention Basin, probably the result of cleaning and decontamination activities at some of the aforementioned facilities. The discharge of waste materials to K-1407-C was discontinued before November of 1988, and all sludge was removed from the retention basin. Some of the sludge was stored, and the remainder was fixed in concrete. This report is specific to the K-1407-C Retention Basin and includes information pertinent to the evaluation of soil contamination. The focus of this evaluation is the effectiveness of the Phase 1 investigation of the K-1407-C Retention Basin to define site conditions adequately to support decisions regarding appropriate closure alternatives. This includes the physical characterization of the site area and the characterization of the nature and extent of contamination at the site in relation to risk characterization and statistical evaluation

Acid-base thermochemistry of gaseous aliphatic α-aminoacids.

Science.gov (United States)

Bouchoux, Guy; Huang, Sihua; Inda, Bhawani Singh

2011-01-14

Acid-base thermochemistry of isolated aliphatic amino acids (denoted AAA): glycine, alanine, valine, leucine, isoleucine and proline has been examined theoretically by quantum chemical computations at the G3MP2B3 level. Conformational analysis on neutral, protonated and deprotonated species has been used to identify the lowest energy conformers and to estimate the population of conformers expected to be present at thermal equilibrium at 298 K. Comparison of the G3MP2B3 theoretical proton affinities, PA, and ΔH(acid) with experimental results is shown to be correct if experimental thermochemistry is re-evaluated and adapted to the most recent acidity-basicity scales. From this point of view, a set of evaluated proton affinities of 887, 902, 915, 916, 919 and 941 kJ mol(-1), and a set of evaluated ΔH(acid) of 1433, 1430, 1423, 1423, 1422 and 1426 kJ mol(-1), is proposed for glycine, alanine, valine, leucine, isoleucine and proline, respectively. Correlations with structural parameters (Taft's σ(α) polarizability parameter and molecular size) suggest that polarizability of the side chain is the major origin of the increase in PA and decrease in ΔH(acid) along the homologous series glycine, alanine, valine and leucine/isoleucine. Heats of formation of gaseous species AAA, AAAH(+) and [AAA-H](-) were computed at the G3MP2B3 level. The present study provides previously unavailable Δ(f)H°(298) for the ionized species AAAH(+) and [AAA-H](-). Comparison with Benson's estimate, and correlation with molecular size, show that several experimental Δ(f)H°(298) values of neutral or gaseous AAA might be erroneous.

Diffuse high-grade gliomas with H3 K27M mutations carry a dismal prognosis independent of tumor location.

Science.gov (United States)

Karremann, Michael; Gielen, Gerrit H; Hoffmann, Marion; Wiese, Maria; Colditz, Niclas; Warmuth-Metz, Monika; Bison, Brigitte; Claviez, Alexander; van Vuurden, Dannis G; von Bueren, André O; Gessi, Marco; Kühnle, Ingrid; Hans, Volkmar H; Benesch, Martin; Sturm, Dominik; Kortmann, Rolf-Dieter; Waha, Andreas; Pietsch, Torsten; Kramm, Christof M

2018-01-10

The novel entity of "diffuse midline glioma, H3 K27M-mutant" has been defined in the 2016 revision of the World Health Organization (WHO) classification of tumors of the central nervous system (CNS). Tumors of this entity arise in CNS midline structures of predominantly pediatric patients and are associated with an overall dismal prognosis. They are defined by K27M mutations in H3F3A or HIST1H3B/C, encoding for histone 3 variants H3.3 and H3.1, respectively, which are considered hallmark events driving gliomagenesis. Here, we characterized 85 centrally reviewed diffuse gliomas on midline locations enrolled in the nationwide pediatric German HIT-HGG registry regarding tumor site, histone 3 mutational status, WHO grade, age, sex, and extent of tumor resection. We found 56 H3.3 K27M-mutant tumors (66%), 6 H3.1 K27M-mutant tumors (7%), and 23 H3-wildtype tumors (27%). H3 K27M-mutant gliomas shared an aggressive clinical course independent of their anatomic location. Multivariate regression analysis confirmed the significant impact of the H3 K27M mutation as the only independent parameter predictive of overall survival (P = 0.009). In H3 K27M-mutant tumors, neither anatomic midline location nor histopathological grading nor extent of tumor resection had an influence on survival. These results substantiate the clinical significance of considering diffuse midline glioma, H3 K27M-mutant, as a distinct entity corresponding to WHO grade IV, carrying a universally fatal prognosis. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Neuro-Oncology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Potential Hazards Relating to Pyrolysis of c-C{sub 4}F{sub 8} in Selected Gaseous Diffusion Plant Operations

Energy Technology Data Exchange (ETDEWEB)

Trowbridge, L.D.

1999-03-01

As part of a program intended to replace the present evaporative coolant at the gaseous diffusion plants (GDPs) with a non-ozone-depleting alternate, a series of investigations of the suitability of candidate substitutes in under way. One issue concerning a primary candidate, c-C4F8, is the possibility that it might produce the highly toxic perfluoroisobutylene (PFIB) in high temperature environments. This study was commissioned to determine the likelihood and severity of decomposition under two specific high temperature thermal environments, namely the use of a flame test for the presence of coolant vapors and welding in the presence of coolant vapors. The purpose of the study was to develop and evaluate available data to provide information that will allow the technical and industrial hygiene staff at the GDPs to perform appropriate safety evaluations and to determine the need for field testing or experimental work. The scope of this study included a literature search and an evaluation of the information developed therefrom. Part of that evaluation consists of chemical kinetics modeling of coolant decomposition in the two operational environments. The general conclusions are that PFIB formation is unlikely in either situation but that it cannot be ruled out completely under extreme conditions. The presence of oxygen, moisture, and combustion products will tend to lead to formation of oxidation products (COF2, CO, CO2, and HF) rather than PFIB.

A 25-kW Series-Resonant Power Converter

Science.gov (United States)

Frye, R. J.; Robson, R. R.

1986-01-01

Prototype exhibited efficiency of 93.9 percent. 25-kW resonant dc/dc power converter designed, developed, fabricated, and tested, using Westinghouse D7ST transistors as high-power switches. D7ST transistor characterized for use as switch in series-resonant converters, and refined base-drive circuit developed. Technical base includes advanced switching magnetic, and filter components, mathematical circuit models, control philosophies, and switch-drive strategies. Power-system benefits such as lower losses when used for high-voltage distribution, and reduced magnetics and filter mass realized.

Detection of Submillimeter-wave [C i] Emission in Gaseous Debris Disks of 49 Ceti and β Pictoris

Energy Technology Data Exchange (ETDEWEB)

Higuchi, Aya E.; Sakai, Nami [The Institute of Physical and Chemical Research (RIKEN), 2-1, Hirosawa, Wako-shi, Saitama 351-0198 (Japan); Sato, Aki; Tsukagoshi, Takashi; Momose, Munetake [College of Science, Ibaraki University, Bunkyo 2-1-1, Mito 310-8512 (Japan); Iwasaki, Kazunari [Department of Environmental Systems Science, Doshisha University, Tatara Miyakodani 1-3, Kyotanabe City, Kyoto 610-0394 (Japan); Kobayashi, Hiroshi; Ishihara, Daisuke; Watanabe, Sakae; Kaneda, Hidehiro [Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602 (Japan); Yamamoto, Satoshi, E-mail: aya.higuchi@riken.jp [Department of Physics, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033 (Japan)

2017-04-10

We have detected [C i] {sup 3} P {sub 1}–{sup 3} P {sub 0} emissions in the gaseous debris disks of 49 Ceti and β Pictoris with the 10 m telescope of the Atacama Submillimeter Telescope Experiment, which is the first detection of such emissions. The line profiles of [C i] are found to resemble those of CO( J = 3–2) observed with the same telescope and the Atacama Large Millimeter/submillimeter Array. This result suggests that atomic carbon (C) coexists with CO in the debris disks and is likely formed by the photodissociation of CO. Assuming an optically thin [C i] emission with the excitation temperature ranging from 30 to 100 K, the column density of C is evaluated to be (2.2 ± 0.2) × 10{sup 17} and (2.5 ± 0.7) × 10{sup 16} cm{sup −2} for 49 Ceti and β Pictoris, respectively. The C/CO column density ratio is thus derived to be 54 ± 19 and 69 ± 42 for 49 Ceti and β Pictoris, respectively. These ratios are higher than those of molecular clouds and diffuse clouds by an order of magnitude. The unusually high ratios of C to CO are likely attributed to a lack of H{sub 2} molecules needed to reproduce CO molecules efficiently from C. This result implies a small number of H{sub 2} molecules in the gas disk, i.e., there is an appreciable contribution of secondary gas from dust grains.

14 CFR Appendix K to Part 25 - Extended Operations (ETOPS)

Science.gov (United States)

2010-01-01

... comply with this appendix, the applicant must demonstrate that: (1) The reliability of the APU is... constraints, and ETOPS approval in a CMP document. K25.1.7Airplane flight manual. The airplane flight manual... cargo or baggage compartments. (e) This statement: “The type-design reliability and performance of this...

Revision of standard molar enthalpies of formation of glycine and L-alanine in the gaseous phase on the basis of theoretical calculations

International Nuclear Information System (INIS)

Dorofeeva, Olga V.; Ryzhova, Oxana N.

2009-01-01

The standard molar enthalpies of formation of urea, glycine, and L-alanine in the gaseous phase at 298.15 K were calculated by the high-level Gaussian-3X method. The agreement with the available experimental data is very good for urea and glycine and, thus, supports the high accuracy of calculated values. A significant discrepancy between theoretical and experimental enthalpy of formation values for L-alanine provides a reason to reconsider the experimental data previously used to derive the standard molar enthalpy of formation of L-alanine in the gaseous phase at 298.15 K. To obtain a more reliable value of enthalpy of sublimation at 298.15 K, the heat capacity values of gaseous L-alanine were calculated by standard statistical thermodynamics formulae using molecular parameters determined from B3LYP/cc-pVTZ calculations. With the obtained value of C p,m 0 (L-alanine, g, 298.15 K) = 112.6 ± 4.0 J . K -1 . mol -1 the original published experimental values of enthalpy of sublimation of L-alanine were readjusted to the reference temperature: Δ cr g H m (L-alanine, 298.15 K) = 135.2 ± 2.0 kJ . mol -1 . This value, together with the experimental enthalpy of formation of solid L-alanine, Δ f H m 0 (L-alanine, cr, 298.15 K) = -560.0 ± 1.0 kJ . mol -1 [S.N. Ngauv, R. Sabbah, M. Laffitte, Thermochim. Acta 20 (1977) 371-380; I. Contineanu, D.I. Marchidan, Rev. Roum. Chim. 29 (1984) 43-48], gives a new value for the enthalpy of formation of L-alanine in the gaseous phase, Δ f H m 0 (L-alanine, g, 298.15 K) = -424.8 ± 2.0 kJ . mol -1 , which is in good agreement with our theoretical G3X result, -427.6 ± 4.0 kJ . mol -1 . The same procedure for glycine allowed us to improve the literature value of the enthalpy of formation for this compound, Δ f H m 0 (glycine, g, 298.15 K) = -393.7 ± 1.5 kJ . mol -1 . As a result a set of self-consistent thermochemical data for glycine and L-alanine is proposed

Reuse of East Tennessee Technology Park (Former K-25 Site) on the Oak Ridge Reservation: Progress, Problems, and Prospects

International Nuclear Information System (INIS)

Gawarecki, S.L.

2009-01-01

facilities transition to private uses and the associated utilities are taken over by local governments to support redevelopment. ETTP is undergoing transformation from a gaseous diffusion plant - with all of the problems posed by aging and potentially contaminated facilities - to a modern private industrial park. A snapshot of progress to date offers a variety of successes and problems. A large D and D effort is ridding the site of dilapidated facilities with a variety of contamination problems. With an eye to the future, the City of Oak Ridge has begun to acquire the site utilities, roadways, and essential support services. A proven system of transferring uncontaminated facilities into the private sector through CROET is in place. These achievements have not been without problems and obstacles. DOE continues to struggle with how to transfer potentially contaminated facilities to companies that have substantial financial and business investments in their buildings. Heritage tourism proponents are dealing with the realities of whether it is possible to preserve a portion of the dilapidated K-25 building and how to address contaminated artifacts and equipment necessary to interpret the site's history. Perhaps the foremost challenge has proved to be DoE's changing priorities over time coupled with uncertain Environmental Management budgets. National priorities have de-emphasized D and D of facilities and remediation of soils and groundwater, which has led to Oak Ridge's cleanup budget being drastically cut in recent years, setting back the projected ETTP completion date to 2016 and similarly delaying subsequent private development. The experiences at ETTP can provide information useful to other nuclear facilities via the IAEA's IDN. The 'lessons learned' at ETTP enhance IAEA's understanding of the difficulties encountered as nuclear facilities transition to other uses, and the site's successes are models for reuse of nuclear facilities elsewhere in the world. Additionally

40-kV, 25-ms neutral-beam power supply for TMX

International Nuclear Information System (INIS)

Leavitt, G.A.

1977-01-01

Modifications are described to upgrade the neutral-beam power supply for the TMX from 40 kV, 10 ms to 40 kV, 25 ms. The redesign of the accel and suppressor power supplies to achieve separation of the high-voltage and control sections, operation of the arc pulse lines in series, operation of the arc pulse lines in a noisy environment with SCR trigger and crowbar, and modifications to the electrolytic storage banks are discussed

Gaseous radioactive waste processing system

International Nuclear Information System (INIS)

Onizawa, Hideo.

1976-01-01

Object: To prevent explosion of hydrogen gas within gaseous radioactive waste by removing the hydrogen gas by means of a hydrogen absorber. Structure: A coolant extracted from a reactor cooling system is sprayed by nozzle into a gaseous phase (hydrogen) portion within a tank, thus causing slipping of radioactive rare gas. The gaseous radioactive waste rich in hydrogen, which is purged in the tank, is forced by a waste gas compressor into a hydrogen occlusion device. The hydrogen occlusion device is filled with hydrogen occluding agents such as Mg, Mg-Ni alloy, V-Nb alloy, La-Ni alloy and so forth, and hydrogen in the waste gas is removed through reaction to produce hydrogen metal. The gaseous radioactive waste, which is deprived of hydrogen and reduced in volume, is stored in an attenuation tank. The hydrogen stored in the hydrogen absorber is released and used again as purge gas. (Horiuchi, T.)

A 2.5-kW industrial CO2 laser

Science.gov (United States)

Golov, V. K.; Ivanchenko, A. I.; Krasheninnikov, V. V.; Ponomarenko, A. G.; Shepelenko, A. A.

1986-06-01

A fast-flow laser is reported in which the active medium is excited by a self-sustained dc discharge produced by an electric-discharge device with nonsectioned electrodes. In the laser, two discharge gaps are formed by a flat anode and two cathodes, one on each side of the anode. A gas mixture is driven through the gasdynamic channel by a centrifugal fan rotating at 6000 rpm/min. With a mixture of CO2:N2:He = 2.5:7.5:5 mm Hg, the rated power is 2.5 kW; the maximum power is 4 kW with the mixture 2.5:7.5:10 mm Hg. The general design of the laser is described, and its principal performance characteristics are given.

Diffusion and evaporation of a liquid droplet

Science.gov (United States)

Shukla, K. N.

1980-06-01

The process of evaporation and diffusion of a spherical liquid droplet in an atmosphere of noncondensable gas is studied theoretically. An equation for the shrinkage of the radius of the droplet is derived on the basis of continuity and momentum equations. Further, a conjugate problem consisting of the energy and mass balance for the gaseous environment is formulated. An approximation of thin thermal and diffusion boundary-layers is introduced to simplify the analysis. Results are presented for methanol-nitrogen, ammonia-nitrogen, and sodium-argon systems. It has been observed that the droplet of highly viscous fluid exhibits rapid contraction.

Mass spectrometric study of thermodynamic properties of gaseous lead tellurates. Estimation of formation enthalpies of gaseous lead polonates

Energy Technology Data Exchange (ETDEWEB)

Shugurov, S.M., E-mail: s.shugurov@spbu.ru; Panin, A.I.; Lopatin, S.I.; Emelyanova, K.A.

2016-10-15

Gaseous reactions involving lead oxides, tellurium oxide and lead tellurates were studied by the Knudsen effusion mass spectrometry. Equilibrium constants and reaction enthalpies were evaluated. Structures, molecular parameters and thermodynamic functions of gaseous PbTeO{sub 3} and Pb{sub 2}TeO{sub 4} were calculated by quantum chemistry methods. The formation enthalpies Δ{sub f}H{sup 0} (298.15) = −294 ± 13 for gaseous PbTeO{sub 3} and Δ{sub f}H{sup 0} (298.15) = −499 ± 12 for gaseous Pb{sub 2}TeO{sub 4} were obtained. On the base of these results the formation enthalpies of gaseous PbPoO{sub 3} and Pb{sub 2}PoO{sub 4} were estimated as −249 ± 34 and −478 ± 38, respectively. - Highlights: • Gaseous lead tellurates PbTeO{sub 3}, Pb{sub 2}TeO{sub 4} were discovered. • Their thermodynamic properties were studied using both high temperature mass spectrometry and quantum chemistry computations. • The obtained data allows to predict the formation enthalpies of gaseous lead polonates PbPoO{sub 3}, Pb{sub 2}PoO{sub 4}.

Fuel clean-up: poisoning of palladium-silver membranes by gaseous impurities

International Nuclear Information System (INIS)

Chabot, J.; Lecomte, J.; Grumet, C.; Sannier, J.

1988-01-01

The feasibility of a permeation process using a palladium-silver alloy membrane, to separate deuterium and tritium from fusion reactor gaseous wastes needs demonstration owing to poisoning effects of impurities. A parametric investigation of the poisoning by the most important expected gaseous impurities (C0, C0 2 and CH 4 ) is carried out with the loop PALLAS, in function of membrane temperature (100 to 450 0 C), H 2 pressure (0.3 to 14 kPa) and impurity concentration (0.2 to 9.5 vol. %). The poisoning effect of C0 is a concern for the process while C0 2 and CH 4 appear to have no practical effect on the permeation rate. Depending on C0 concentration optimal operating temperatures of the membrane should lie between 250 and 375 0 C limits

Apparatus for diffusion-gap thermal desalination

Science.gov (United States)

Lowenstein, Andrew

2017-09-26

A thermal distillation apparatus including evaporation surfaces that are wetted with a solution, and from which at least some of the volatile solvent contained in the solution evaporates, condensers having an external surface in close proximity to, but not touching, a corresponding one of the one or more evaporation surfaces, and on which vapors of the solvent condense, releasing thermal energy that heats a flow of the solution moving upward within the condensers, spacers that prevent contact between the evaporating surfaces and the condensers, wherein spaces between the evaporating surfaces and the condensers are filled with a gaseous mixture composed of solvent vapor and one or more non-condensable gases, and except for diffusion of the solvent vapor relative to the non-condensable gases, the gaseous mixture is stationary.

Effects of gaseous ammonia direct injection on performance characteristics of a spark-ignition engine

International Nuclear Information System (INIS)

Ryu, Kyunghyun; Zacharakis-Jutz, George E.; Kong, Song-Charng

2014-01-01

Highlights: • This is the very first study in utilizing direct injection of gaseous ammonia in an SI engine. • Engine combustion using direct injection of gaseous ammonia is proven feasible. • Energy efficiency using ammonia is comparable to that using gasoline. • CO emissions are decreased but emissions of NOx and HC are increased when ammonia is used. - Abstract: The effects of direct injection of gaseous ammonia on the combustion characteristics and exhaust emissions of a spark-ignition engine were investigated. Port-injection gasoline was used to enhance the burning of ammonia that was directly injected into the engine cylinder. Appropriate direct injection strategies were developed to allow ammonia to be used in spark-ignition engines without sacrifice of volumetric efficiency. Experimental results show that with gasoline providing the baseline power of 0.6 kW, total engine power could increase to 2.7 kW when the injection timing of ammonia was advanced to 370 BTDC with injection duration of 22 ms. Engine performance with use of gasoline–ammonia was compared to that with gasoline alone. For operations using gasoline–ammonia, with baseline power from gasoline at 0.6 kW the appropriate ammonia injection timing was found to range from 320 to 370 BTDC for producing 1.5–2.7 kW. The peak pressures were slightly lower than those using gasoline alone because of the lower flame of ammonia, resulting in reduction of cylinder pressure. The brake specific energy consumption (BSEC) with gasoline–ammonia was very similar to that with gasoline alone. Ammonia direct injection caused slight reductions of BSCO for all the loads studied but significantly increased BSHC because of the reduced combustion temperature of ammonia combustion. The use of ammonia resulted in increased NOx emissions because of formation of fuel NOx. Ammonia slip was also detected in the engine exhaust because of incomplete combustion

Biodegradation polyurethane derived from vegetable oil irradiated with gamma rays 25 kGy and 100 kGy; Biodegradacao de poliuretano derivado de oleo vegetal irradiado com raios gama 25 kGy e 100 kGy

Energy Technology Data Exchange (ETDEWEB)

Santos, Antonia M. dos, E-mail: amsantos@rc.unesp.br [Universidade Estadual Paulista - Unesp, Rio Claro, SP (Brazil); Claro Neto, Salvador [Universidade de Sao Paulo - USP, Campus de Sao Carlos, SP (Brazil); Azevedo, Elaine C. de [Universidade Federal do Parana, Campus de Curitiba, PR (Brazil)

2011-07-01

The environment requires polymers that can be degraded by the action of microorganisms. In this work was studied the biodegradation of polyurethane samples derived from vegetable oil (castor oil), which were irradiated with gamma rays 25 kGy and 100 kGy compared with the same polyurethane without being irradiated. Biodegradation of polyurethane was carried out in culture medium containing the fungus Aspergillus niger by 146 days and the result was evaluated using the technique of thermogravimetric analysis, where there was a change of behavior of the curves TGA / DTG occurred indicating that chemical modifications of molecules present in the structure of the polymer chain, thus confirming that the material has undergone the action of microorganisms. (author)

Gaseous-fuel nuclear reactor research for multimegawatt power in space

Science.gov (United States)

Thom, K.; Schneider, R. T.; Helmick, H. H.

1977-01-01

In the gaseous-fuel reactor concept, the fissile material is contained in a moderator-reflector cavity and exists in the form of a flowing gas or plasma separated from the cavity walls by means of fluid mechanical forces. Temperatures in excess of structural limitations are possible for low-specific-mass power and high-specific-impulse propulsion in space. Experiments have been conducted with a canister filled with enriched UF6 inserted into a beryllium-reflected cavity. A theoretically predicted critical mass of 6 kg was measured. The UF6 was also circulated through this cavity, demonstrating stable reactor operation with the fuel in motion. Because the flowing gaseous fuel can be continuously processed, the radioactive waste in this type of reactor can be kept small. Another potential of fissioning gases is the possibility of converting the kinetic energy of fission fragments directly into coherent electromagnetic radiation, the nuclear pumping of lasers. Numerous nuclear laser experiments indicate the possibility of transmitting power in space directly from fission energy. The estimated specific mass of a multimegawatt gaseous-fuel reactor power system is from 1 to 5 kg/kW while the companion laser-power receiver station would be much lower in specific mass.

Self-Diffusion and Heteroassociation in an Acetone-Chloroform Mixture at 298 K

Science.gov (United States)

Golubev, V. A.; Gurina, D. L.; Kumeev, R. S.

2018-01-01

The self-diffusion coefficients of acetone and chloroform in a binary acetone-chloroform mixture at 298 K are determined via pulsed field gradient NMR spectroscopy. It is estimated that the hydrodynamic radii of the mixture's components, calculated using the Stokes-Einstein equation, grow as the concentrations of the components fall. It is shown that such behavior of hydrodynamic radii is due to acetone-chloroform heteroassociation. The hydrodynamic radii of monomers and heteroassociates in a 1: 1 ratio are determined along with the constant of heteroassociation, using the proposed model of an associated solution.

High efficiency diffusion molecular retention tumor targeting.

Directory of Open Access Journals (Sweden)

Yanyan Guo

Full Text Available Here we introduce diffusion molecular retention (DMR tumor targeting, a technique that employs PEG-fluorochrome shielded probes that, after a peritumoral (PT injection, undergo slow vascular uptake and extensive interstitial diffusion, with tumor retention only through integrin molecular recognition. To demonstrate DMR, RGD (integrin binding and RAD (control probes were synthesized bearing DOTA (for (111 In(3+, a NIR fluorochrome, and 5 kDa PEG that endows probes with a protein-like volume of 25 kDa and decreases non-specific interactions. With a GFP-BT-20 breast carcinoma model, tumor targeting by the DMR or i.v. methods was assessed by surface fluorescence, biodistribution of [(111In] RGD and [(111In] RAD probes, and whole animal SPECT. After a PT injection, both probes rapidly diffused through the normal and tumor interstitium, with retention of the RGD probe due to integrin interactions. With PT injection and the [(111In] RGD probe, SPECT indicated a highly tumor specific uptake at 24 h post injection, with 352%ID/g tumor obtained by DMR (vs 4.14%ID/g by i.v.. The high efficiency molecular targeting of DMR employed low probe doses (e.g. 25 ng as RGD peptide, which minimizes toxicity risks and facilitates clinical translation. DMR applications include the delivery of fluorochromes for intraoperative tumor margin delineation, the delivery of radioisotopes (e.g. toxic, short range alpha emitters for radiotherapy, or the delivery of photosensitizers to tumors accessible to light.

Apparatus for studying the diffusion of rare gases in stainless steel

International Nuclear Information System (INIS)

Stohr, J.A.; Alfille, L.

1959-01-01

This apparatus enables measurements to be carried out on the diffusion of gaseous fission products and of gases in general across thin metallic walls at high temperatures. This work was initially intended to solve the problems involved in systems for detecting the rupture of a fuel element can (D.R.G.) by the diffusion of fission products through the cans at high temperatures. The extension of the work to other fields is envisaged. (author) [fr

Development of a passive sampler for gaseous mercury

Science.gov (United States)

Gustin, M. S.; Lyman, S. N.; Kilner, P.; Prestbo, E.

2011-10-01

Here we describe work toward development of the components of a cost effective passive sampling system for gaseous Hg that could be broadly deployed by nontechnical staff. The passive sampling system included an external shield to reduce turbulence and exposure to precipitation and dust, a diffusive housing that directly protects the collection surface during deployment and handling, and a collection surface. A protocol for cleaning and deploying the sampler and an analytical method were developed. Our final design consisted of a polycarbonate external shield enclosing a custom diffusive housing made from expanded PTFE tubing. Two collection surfaces were investigated, gold sputter-coated quartz plates and silver wires. Research showed the former would require extensive quality control for use, while the latter had interferences with other atmosphere constituents. Although the gold surface exhibited the best performance over space and time, gradual passivation would limit reuse. For both surfaces lack of contamination during shipping, deployment and storage indicated that the handling protocols developed worked well with nontechnical staff. We suggest that the basis for this passive sampling system is sound, but further exploration and development of a reliable collection surface is needed.

Experimental evidence of hydrogen–oxygen decoupled diffusion into BaZr0.6Ce0.25Y0.15O3−δ

International Nuclear Information System (INIS)

Lim, D.-K.; Im, H.-N.; Jeon, S.-Y.; Park, J.-Y.; Song, S.-J.

2013-01-01

The electrical properties of BaZr 0.6 Ce 0.25 Y 0.15 O 3−δ (BZCY) were studied as a function of both oxygen partial pressure (-2.65⩽log(P O 2 atm -1 )⩽-0.62) and water vapor activity (-3.33⩽log(P H 2 O atm -1 ⩽-1.3)) in the temperature range of 973–1073 K. The total conductivity slightly increased in reducing atmospheres with increasing water vapor activity because of the relative contribution to the total conductivity by the redox reaction at the given thermodynamic conditions. The partial conductivities of protons, holes and oxygen vacancies were successfully calculated, and the activation energy determined for proton transport was 0.3 ± 0.1 eV. The chemical diffusivity of oxygen at a fixed water vapor activity, D ∼ vO , could only be evaluated from Fick’s second law during oxidation and reduction at the fixed water vapor activity. However, twofold nonmonotonic conductivity relaxation behaviors were clearly confirmed in the temperature range investigated during hydration/dehydration. If P O 2 represents the fixed oxygen partial pressure, D ∼ iH is the hydrogen chemical diffusivity at P O 2 and D ∼ vH is the oxygen chemical diffusivity at P O 2 , it was observed that D ∼ iH >D ∼ vH at all experimental conditions, suggesting that the hydrogen chemical diffusion is always faster than oxygen on hydration/dehydration in the temperature range studied

Development Status of Diffusion Code RAST-K 2.0 at UNIST

Energy Technology Data Exchange (ETDEWEB)

Park, Minyong; Zheng, Youqi; Choe, Jiwon; Zhang, Peng; Lee, Deokjung [UNIST, Ulsan (Korea, Republic of); Lee, Eunki; Shin, Hocheol [KHNP Central Research Institute, Daejeon (Korea, Republic of)

2016-10-15

The non-linear scheme was used based on the 2-group CMFD and a three dimensional multi -group unified nodal method (UNM). To consider the history effects, the main heavy isotopes were tracked by micro-depletion module using CRAM. The simplified 1-D single channel thermal hydraulic solver from nTACER is implemented. The θ method was adopted in the transient calculation. To get detailed pin-wise power and burnup distribution, Pin power reconstruction module was implemented. Also automatic control logic to calculate MTC, FTC, control rod worth was implemented. To perform multicycle analysis, restart and shuffling/rotation module has been implemented. To link between CASMO-4E and RAST-K 2.0, CATORA (CASMO TO RAST-K 2.0) code was developed. Unlike the other diffusion codes, RAST-K 2.0 depletion module uses CRAM and extended depletion chain for fission products. Most lattice codes give cumulative fission yield of Pm-149 without considering Pm-148 and Pm-149 capture reaction which will lead to the increase of Sm-149 number density. This paper reports the status of RAST-K 2.0 code development at UNIST. The new code applies a new kernel based on the two-node UNM with CMFD, and θ method for kinetic calculation. Also, the microdepletion calculation is used to consider the history effects. And other modules and functions also implemented such as pin power reconstruction, branch calculation, restart, multi-cycle, and 1-D single channel T/H solver.

The conditions of gaseous fuels development

International Nuclear Information System (INIS)

Anon.

1996-01-01

Face to the actual situation of petrol and gas oil in France, the situation of gaseous fuels appears to be rather modest. However, the aim of gaseous fuels is not to totally supersede the liquid fuels. Such a situation would imply a complete overturn which has not been seriously considered yet. This short paper describes the essential conditions to promote the wider use of gaseous fuels: the intervention of public authorities to adopt a more advantageous tax policy in agreement with the ''Clean Air''law project, a suitable distribution network for gaseous fuels, a choice of vehicles consistent with the urban demand, the development of transformation kits of quality and of dual-fuel vehicles by the car manufacturers. (J.S.)

Position-sensitive gaseous photomultipliers research and applications

CERN Document Server

Francke, Tom; Peskov, Vladimir

2016-01-01

Gaseous photomultipliers are defined as gas-filled devices capable of recording single ultraviolet (UV) and visible photons with high position resolution. Used in a variety of research areas, these detectors can be paired with computers to treat and store imaging information of UV-light. Position-Sensitive Gaseous Photomultipliers: Research and Applications explores the advancement of gaseous detectors as applied for single photon detection. Emphasizing emerging perspectives and new ways to apply gaseous detectors across research fields, this research-based publication is an essential reference source for engineers, physicists, graduate-level students, and researchers.

Method of eliminating gaseous hydrogen isotopes

International Nuclear Information System (INIS)

Nagakura, Masaaki; Imaizumi, Hideki; Suemori, Nobuo; Aizawa, Takashi; Naito, Taisei.

1983-01-01

Purpose: To prevent external diffusion of gaseous hydrogen isotopes such as tritium or the like upon occurrence of tritium leakage accident in a thermonuclear reactor by recovering to eliminate the isotopes rapidly and with safety. Method: Gases at the region of a reactor container where hydrogen isotopes might leak are sucked by a recycing pump, dehumidified in a dehumidifier and then recycled from a preheater through a catalytic oxidation reactor to a water absorption tower. In this structure, the dehumidifier is disposed at the upstream of the catalytic oxidation reactor to reduce the water content of the gases to be processed, whereby the eliminating efficiency for the gases to be processed can be maintained well even when the oxidation reactor is operated at a low temperature condition near the ambient temperature. This method is based on the fact that the oxidating reactivity of the catalyst can be improved significantly by eliminating the water content in the gases to be processed. (Yoshino, Y.)

The gaseous enthalpy of formation of the ionic liquid 1-butyl-3-methylimidazolium dicyanamide from combustion calorimetry, vapor pressure measurements, and ab initio calculations.

Science.gov (United States)

Emel'yanenko, Vladimir N; Verevkin, Sergey P; Heintz, Andreas

2007-04-04

Ionic liquids are attracting growing interest as alternatives to conventional molecular solvents. Experimental values of vapor pressure, enthalpy of vaporization, and enthalpy of formation of ionic liquids are the key thermodynamic quantities, which are required for the validation and development of the molecular modeling and ab initio methods toward this new class of solvents. In this work, the molar enthalpy of formation of the liquid 1-butyl-3-methylimidazolium dicyanamide, 206.2 +/- 2.5 kJ.mol-1, was measured by means of combustion calorimetry. The molar enthalpy of vaporization of 1-butyl-3-methylimidazolium dicyanamide, 157.2 +/- 1.1 kJ.mol-1, was obtained from the temperature dependence of the vapor pressure measured using the transpiration method. The latter method has been checked with measurements of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, where data are available from the effusion technique. The first experimental determination of the gaseous enthalpy of formation of the ionic liquid 1-butyl-3-methylimidazolium dicyanamide, 363.4 +/- 2.7 kJ.mol-1, from thermochemical measurements (combustion and transpiration) is presented. Ab initio calculations of the enthalpy of formation in the gaseous phase have been performed for 1-butyl-3-methylimidazolium dicyanamide using the G3MP2 theory. Excellent agreement with experimental results has been observed. The method developed opens a new way to obtain thermodynamic properties of ionic liquids which have not been available so far.

A quaternary lead based perovskite structured materials with diffuse phase transition behavior

International Nuclear Information System (INIS)

Puli, Venkata Sreenivas; Martínez, R.; Kumar, Ashok; Scott, J.F.; Katiyar, Ram S.

2011-01-01

Graphical abstract: (a) Curie–Weiss plot for the inverse of the relative dielectric permittivity and (b) log (1/ε − 1/ε m ) as function of log (T − T m ) for ceramics at 1 kHz. Highlights: ► Retaining phase pure structure with quaternary complex stoichiometric compositions. ► P–E loops with good saturation polarization (P s ∼ 30.7 μC/cm 2 ). ► Diffused relaxor phase transition behavior with γ estimated is ∼1.65. -- Abstract: A lead based quaternary compound composed of 0.25(PbZr 0.52 Ti 0.48 O 3 ) + 0.25(PbFe 0.5 Ta 0.5 O 3 ) + 0.25 (PbF 0.67 W 0.33 O 3 ) + 0.25(PbFe 0.5 Nb 0.5 O 3 ) – (PZT–PFT–PFW–PFN) was synthesized by conventional solid-state reaction techniques. It showed moderate high dielectric constant, low dielectric loss, and two diffuse phase transitions, one below the room temperature ∼261 K and other above ∼410 K. X-ray diffraction (XRD) patterns revealed a tetragonal crystal structure at room temperature where as scanning electron micrograph (SEM) indicates inhomogeneous surface with an average grain size of 500 nm–3 μm. Well saturated ferroelectric hysteresis loops with good saturation polarization (spontaneous polarization, P s ∼ 30.68 μC/cm 2 ) were observed. Temperature-dependent ac conductivity displayed low conductivity with kink in spectra near the phase transition. In continuing search for developing new ferroelectric materials, in the present study we report stoichiometric compositions of complex perovskite ceramic materials: (PZT–PFT–PFW–PFN) with diffuse phase transition behavior. The crystal structure, dielectric properties, and ferroelectric properties were characterized by XRD, SEM, dielectric spectroscopy, and polarization. 1/ε versus (T) plots revealed diffuse relaxor phase transition (DPT) behavior. The compositional variation on the phase transition temperature, dielectric constant, and ferroelectric to paraelectric phase transitions are discussed.

A quaternary lead based perovskite structured materials with diffuse phase transition behavior

Energy Technology Data Exchange (ETDEWEB)

Puli, Venkata Sreenivas, E-mail: pvsri123@gmail.com [Department of Physics and Institute for Functional Nano Materials, University of Puerto Rico, San Juan, PR 00936 (United States); Martinez, R.; Kumar, Ashok [Department of Physics and Institute for Functional Nano Materials, University of Puerto Rico, San Juan, PR 00936 (United States); Scott, J.F. [Department of Physics and Institute for Functional Nano Materials, University of Puerto Rico, San Juan, PR 00936 (United States); Cavendish Laboratory, Dept. Physics, University of Cambridge, Cambridge CB0 3HE (United Kingdom); Katiyar, Ram S., E-mail: rkatiyar@uprrp.edu [Department of Physics and Institute for Functional Nano Materials, University of Puerto Rico, San Juan, PR 00936 (United States)

2011-12-15

Graphical abstract: (a) Curie-Weiss plot for the inverse of the relative dielectric permittivity and (b) log (1/{epsilon} - 1/{epsilon}{sub m}) as function of log (T - T{sub m}) for ceramics at 1 kHz. Highlights: Black-Right-Pointing-Pointer Retaining phase pure structure with quaternary complex stoichiometric compositions. Black-Right-Pointing-Pointer P-E loops with good saturation polarization (P{sub s} {approx} 30.7 {mu}C/cm{sup 2}). Black-Right-Pointing-Pointer Diffused relaxor phase transition behavior with {gamma} estimated is {approx}1.65. -- Abstract: A lead based quaternary compound composed of 0.25(PbZr{sub 0.52}Ti{sub 0.48}O{sub 3}) + 0.25(PbFe{sub 0.5}Ta{sub 0.5}O{sub 3}) + 0.25 (PbF{sub 0.67}W{sub 0.33}O{sub 3}) + 0.25(PbFe{sub 0.5}Nb{sub 0.5}O{sub 3}) - (PZT-PFT-PFW-PFN) was synthesized by conventional solid-state reaction techniques. It showed moderate high dielectric constant, low dielectric loss, and two diffuse phase transitions, one below the room temperature {approx}261 K and other above {approx}410 K. X-ray diffraction (XRD) patterns revealed a tetragonal crystal structure at room temperature where as scanning electron micrograph (SEM) indicates inhomogeneous surface with an average grain size of 500 nm-3 {mu}m. Well saturated ferroelectric hysteresis loops with good saturation polarization (spontaneous polarization, P{sub s} {approx} 30.68 {mu}C/cm{sup 2}) were observed. Temperature-dependent ac conductivity displayed low conductivity with kink in spectra near the phase transition. In continuing search for developing new ferroelectric materials, in the present study we report stoichiometric compositions of complex perovskite ceramic materials: (PZT-PFT-PFW-PFN) with diffuse phase transition behavior. The crystal structure, dielectric properties, and ferroelectric properties were characterized by XRD, SEM, dielectric spectroscopy, and polarization. 1/{epsilon} versus (T) plots revealed diffuse relaxor phase transition (DPT) behavior. The

The Successful Operation of Hole-type Gaseous Detectors at Cryogenic Temperatures

CERN Document Server

Pereiale, L.; Iacobaeus, C.; Francke, T.; Lund-Jensen, B.; Pavlopoulos, P.; Picchi, P.; Pietropaolo, F.; Tokanai, F.

2004-01-01

We have demonstrated that hole-type gaseous detectors, GEMs and capillary plates, can operate up to 77 K. For example, a single capillary plate can operate at gains of above 10E3 in the entire temperature interval between 300 until 77 K. The same capillary plate combined with CsI photocathodes could operate perfectly well at gains (depending on gas mixtures) of 100-1000. Obtained results may open new fields of applications for capillary plates as detectors of UV light and charge particles at cryogenic temperatures: noble liquid TPCs, WIMP detectors or LXe scintillating calorimeters and cryogenic PETs.

Thermal discharges from Paducah Gaseous Diffusion Plant outfalls: Impacts on stream temperatures and fauna of Little Bayou and Big Bayou Creeks

International Nuclear Information System (INIS)

Roy, W.K.; Ryon, M.G.; Hinzman, R.L.

1996-03-01

The development of a biological monitoring plan for the receiving streams of the Paducah Gaseous Diffusion Plant (PGDP) began in the late 1980s, because of an Agreed Order (AO) issued in September 1987 by the Kentucky Division of Water (KDOW). Five years later, in September 1992, more stringent effluent limitations were imposed upon the PGDP operations when the KDOW reissued Kentucky Pollutant Discharge Elimination System permit No. KY 0004049. This action prompted the US Department of Energy (DOE) to request a stay of certain limits contained in the permit. An AO is being negotiated between KDOW, the US Enrichment Corporation (USEC), and DOE that will require that several studies be conducted, including this stream temperature evaluation study, in an effort to establish permit limitations. All issues associated with this AO have been resolved, and the AO is currently being signed by all parties involved. The proposed effluent temperature limit is 89 F (31.7 C) as a mean monthly temperature. In the interim, temperatures are not to exceed 95 F (35 C) as a monthly mean or 100 F (37.8 C) as a daily maximum. This study includes detailed monitoring of instream temperatures, benthic macroinvertebrate communities, fish communities, and a laboratory study of thermal tolerances

Thermal discharges from Paducah Gaseous Diffusion Plant outfalls: Impacts on stream temperatures and fauna of Little Bayou and Big Bayou Creeks

Energy Technology Data Exchange (ETDEWEB)

Roy, W.K.; Ryon, M.G.; Hinzman, R.L. [Oak Ridge National Lab., TN (United States). Computer Science and Mathematics Div.

1996-03-01

The development of a biological monitoring plan for the receiving streams of the Paducah Gaseous Diffusion Plant (PGDP) began in the late 1980s, because of an Agreed Order (AO) issued in September 1987 by the Kentucky Division of Water (KDOW). Five years later, in September 1992, more stringent effluent limitations were imposed upon the PGDP operations when the KDOW reissued Kentucky Pollutant Discharge Elimination System permit No. KY 0004049. This action prompted the US Department of Energy (DOE) to request a stay of certain limits contained in the permit. An AO is being negotiated between KDOW, the US Enrichment Corporation (USEC), and DOE that will require that several studies be conducted, including this stream temperature evaluation study, in an effort to establish permit limitations. All issues associated with this AO have been resolved, and the AO is currently being signed by all parties involved. The proposed effluent temperature limit is 89 F (31.7 C) as a mean monthly temperature. In the interim, temperatures are not to exceed 95 F (35 C) as a monthly mean or 100 F (37.8 C) as a daily maximum. This study includes detailed monitoring of instream temperatures, benthic macroinvertebrate communities, fish communities, and a laboratory study of thermal tolerances.

Thermal Discharges from Paducah Gaseous Diffusion Plant Outfalls: Impacts on Stream Temperatures and Fauna of Little Bayou and Big Bayou Creeks

International Nuclear Information System (INIS)

Roy, W.K.

1999-01-01

The development of a biological monitoring plan for the receiving streams of the Paducah Gaseous Diffusion Plant (PGDP) began in the late 1980s, because of an Agreed Order (AO) issued in September 1987 by the Kentucky Division of Water (KDOW). Five years later, in September 1992, more stringent effluent limitations were imposed upon the PGDP operations when the KDOW reissued Kentucky Pollutant Discharge Elimination System permit No. KY 0004049. This action prompted the US Department of Energy (DOE) to request a stay of certain limits contained in the permit. An AO is being negotiated between KDOW, the United States Enrichment Corporation (USEC), and DOE that will require that several studies be conducted, including this stream temperature evaluation study, in an effort to establish permit limitations. All issues associated with this AO have been resolved, and the AO is currently being signed by all parties involved. The proposed effluent temperature limit is 89 F (31.7C) as a mean monthly temperature. In the interim, temperatures are not to exceed 95 F (35 C) as a monthly mean or 100 F (37.8 C) as a daily maximum. This study includes detailed monitoring of instream temperatures, benthic macroinvertebrate communities, fish communities, and a laboratory study of thermal tolerances

Thermal Discharges from Paducah Gaseous Diffusion Plant Outfalls: Impacts on Stream Temperatures and Fauna of Little Bayou and Big Bayou Creeks

Energy Technology Data Exchange (ETDEWEB)

Roy, W.K.

1999-01-01

The development of a biological monitoring plan for the receiving streams of the Paducah Gaseous Diffusion Plant (PGDP) began in the late 1980s, because of an Agreed Order (AO) issued in September 1987 by the Kentucky Division of Water (KDOW). Five years later, in September 1992, more stringent effluent limitations were imposed upon the PGDP operations when the KDOW reissued Kentucky Pollutant Discharge Elimination System permit No. KY 0004049. This action prompted the US Department of Energy (DOE) to request a stay of certain limits contained in the permit. An AO is being negotiated between KDOW, the United States Enrichment Corporation (USEC), and DOE that will require that several studies be conducted, including this stream temperature evaluation study, in an effort to establish permit limitations. All issues associated with this AO have been resolved, and the AO is currently being signed by all parties involved. The proposed effluent temperature limit is 89 F (31.7C) as a mean monthly temperature. In the interim, temperatures are not to exceed 95 F (35 C) as a monthly mean or 100 F (37.8 C) as a daily maximum. This study includes detailed monitoring of instream temperatures, benthic macroinvertebrate communities, fish communities, and a laboratory study of thermal tolerances.

Temporal relationships between the variations of diffuse gaseous emanations and the explosive activity of some active volcanoes of Costa-Rica, examples at the Arenal, Irazu and at the Rincon de la Vieja; Relations temporelles entre les variations des emanations gazeuses diffuses et l`activite explosive de quelques volcans actifs du Costa-Rica, exemples a l`Arenal, l`Irazu et au Rincon de la Vieja

Energy Technology Data Exchange (ETDEWEB)

Baubron, J C [BRGM, 45 - Orleans (France); Allard, P [CEA Centre d` Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Direction des Sciences de la Matiere; Fernandez, E [Obviscori, Heridia (Costa Rica); Hammouya, G [Observatoire de la Soufriere, IPG-P, le Houelmont, 97 - Gourgeyre (France); Soto, G J [ICE, San Jose (Costa Rica)

1997-12-31

The surveillance of the temporal evolution of radon and helium concentrations in the carbon dioxide of crater fumaroles and gaseous emanations is performed since 1992 on the Irazu, Arenal, Poas and Rincon de la Vieja volcanoes in Costa-Rica. The {sup 3}He/{sup 4}He ratio is used as an indicator of the deep origin of the volcanic gas while radon is an indicator of the CO{sub 2} flux. Radon measurements performed on the Irazu show a continuous decay of radon concentration in the intra-crater fumaroles with an important increase of the gaseous flux since 1992. On the contrary, the external fumaroles on the NW flank were characterized by an important increase in radon concentration in 1994 with a stable flux. The radon surveillance performed in soils around the volcano has shown an intense increase of the diffuse gaseous flows probably linked to the micro-seismic activity of the volcano. Similar observations are reported for the Rincon de la Vieja volcano and correlated with its eruptive history and its phreatic and phreato-magmatic activity. Short paper. (J.S.).

Temporal relationships between the variations of diffuse gaseous emanations and the explosive activity of some active volcanoes of Costa-Rica, examples at the Arenal, Irazu and at the Rincon de la Vieja; Relations temporelles entre les variations des emanations gazeuses diffuses et l`activite explosive de quelques volcans actifs du Costa-Rica, exemples a l`Arenal, l`Irazu et au Rincon de la Vieja

Energy Technology Data Exchange (ETDEWEB)

Baubron, J.C. [BRGM, 45 - Orleans (France); Allard, P. [CEA Centre d`Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Direction des Sciences de la Matiere; Fernandez, E. [Obviscori, Heridia (Costa Rica); Hammouya, G. [Observatoire de la Soufriere, IPG-P, le Houelmont, 97 - Gourgeyre (France); Soto, G.J. [ICE, San Jose (Costa Rica)

1996-12-31

The surveillance of the temporal evolution of radon and helium concentrations in the carbon dioxide of crater fumaroles and gaseous emanations is performed since 1992 on the Irazu, Arenal, Poas and Rincon de la Vieja volcanoes in Costa-Rica. The {sup 3}He/{sup 4}He ratio is used as an indicator of the deep origin of the volcanic gas while radon is an indicator of the CO{sub 2} flux. Radon measurements performed on the Irazu show a continuous decay of radon concentration in the intra-crater fumaroles with an important increase of the gaseous flux since 1992. On the contrary, the external fumaroles on the NW flank were characterized by an important increase in radon concentration in 1994 with a stable flux. The radon surveillance performed in soils around the volcano has shown an intense increase of the diffuse gaseous flows probably linked to the micro-seismic activity of the volcano. Similar observations are reported for the Rincon de la Vieja volcano and correlated with its eruptive history and its phreatic and phreato-magmatic activity. Short paper. (J.S.).

Treatment of Radioactive Gaseous Waste

International Nuclear Information System (INIS)

2014-07-01

Radioactive waste, with widely varying characteristics, is generated from the operation and maintenance of nuclear power plants, nuclear fuel cycle facilities, research laboratories and medical facilities. The waste needs to be treated and conditioned as necessary to provide waste forms acceptable for safe storage and disposal. Although radioactive gaseous radioactive waste does not constitute the main waste flow stream at nuclear fuel cycle and radioactive waste processing facilities, it represents a major source for potential direct environmental impact. Effective control and management of gaseous waste in both normal and accidental conditions is therefore one of the main issues of nuclear fuel cycle and waste processing facility design and operation. One of the duties of an operator is to take measures to avoid or to optimize the generation and management of radioactive waste to minimize the overall environmental impact. This includes ensuring that gaseous and liquid radioactive releases to the environment are within authorized limits, and that doses to the public and the effects on the environment are reduced to levels that are as low as reasonably achievable. Responsibilities of the regulatory body include the removal of radioactive materials within authorized practices from any further regulatory control — known as clearance — and the control of discharges — releases of gaseous radioactive material that originate from regulated nuclear facilities during normal operation to the environment within authorized limits. These issues, and others, are addressed in IAEA Safety Standards Series Nos RS-G-1.7, WS-G-2.3 and NS-G-3.2. Special systems should be designed and constructed to ensure proper isolation of areas within nuclear facilities that contain gaseous radioactive substances. Such systems consist of two basic subsystems. The first subsystem is for the supply of clean air to the facility, and the second subsystem is for the collection, cleanup and

Diffusion in molybdenum disilicide

International Nuclear Information System (INIS)

Salamon, M.; Mehrer, H.

2005-01-01

The diffusion behaviour of the high-temperature material molybdenum disilicide (MoSi 2 ) was completely unknown until recently. In this paper we present studies of Mo self-diffusion and compare our present results with our already published studies of Si and Ge diffusion in MoSi 2 . Self-diffusion of molybdenum in monocrystalline MoSi 2 was studied by the radiotracer technique using the radioisotope 99 Mo. Deposition of the radiotracer and serial sectioning after the diffusion anneals to determine the concentration-depth profiles was performed using a sputtering device. Diffusion of Mo is a very slow process. In the entire temperature region investigated (1437 to 2173 K), the 99 Mo diffusivities in both principal directions of the tetragonal MoSi 2 crystals obey Arrhenius laws, where the diffusion perpendicular to the tetragonal axis is faster by two to three orders of magnitude than parallel to it. The activation enthalpies for diffusion perpendicular and parallel to the tetragonal axis are Q perpendicular to = 468 kJ mol -1 (4.85 eV) and Q parallel = 586 kJ mol -1 (6.07 eV), respectively. Diffusion of Si and its homologous element Ge is fast and is mediated by thermal vacancies of the Si sublattice of MoSi 2 . The diffusion of Mo is by several orders of magnitude slower than the diffusion of Si and Ge. This large difference suggests that Si and Mo diffusion are decoupled and that the diffusion of Mo likely takes place via vacancies on the Mo sublattice. (orig.)

Field evaluation of a horizontal well recirculation system for groundwater treatment: Field demonstration at X-701B Portsmouth Gaseous Diffusion Plant, Piketon, Ohio

International Nuclear Information System (INIS)

Korte, N.; Muck, M.; Kearl, P.; Siegrist, R.; Schlosser, R.; Zutman, J.; Houk, T.

1998-01-01

This report describes the field-scale demonstration performed as part of the project, In Situ Treatment of Mixed Contaminants in Groundwater. This project was a 3 1/2 year effort comprised of laboratory work performed at Oak Ridge National Laboratory and fieldwork performed at the US Department of Energy (DOE) Portsmouth Gaseous Diffusion Plant (PORTS). The overall goal of the project was to evaluate in situ treatment of groundwater using horizontal recirculation coupled with treatment modules. Specifically, horizontal recirculation was tested because of its application to thin, interbedded aquifer zones. Mixed contaminants were targeted because of their prominence at DOE sites and because they cannot be treated with conventional methods. The project involved several research elements, including treatment process evaluation, hydrodynamic flow and transport modeling, pilot testing at an uncontaminated site, and full-scale testing at a contaminated site. This report presents the results of the work at the contaminated site, X-701B at PORTS. Groundwater contamination at X-701B consists of trichloroethene (TCE) (concentrations up to 1800 mg/L) and technetium-998 (Tc 99 ) (activities up to 926 pCi/L)

Field evaluation of a horizontal well recirculation system for groundwater treatment: Field demonstration at X-701B Portsmouth Gaseous Diffusion Plant, Piketon, Ohio

Energy Technology Data Exchange (ETDEWEB)

Korte, N.; Muck, M.; Kearl, P.; Siegrist, R.; Schlosser, R.; Zutman, J. [Oak Ridge National Lab., TN (United States); Houk, T. [Lockheed Martin Energy Systems, Piketon, OH (United States). Portsmouth Gaseous Diffusion Plant

1998-08-01

This report describes the field-scale demonstration performed as part of the project, In Situ Treatment of Mixed Contaminants in Groundwater. This project was a 3{1/2} year effort comprised of laboratory work performed at Oak Ridge National Laboratory and fieldwork performed at the US Department of Energy (DOE) Portsmouth Gaseous Diffusion Plant (PORTS). The overall goal of the project was to evaluate in situ treatment of groundwater using horizontal recirculation coupled with treatment modules. Specifically, horizontal recirculation was tested because of its application to thin, interbedded aquifer zones. Mixed contaminants were targeted because of their prominence at DOE sites and because they cannot be treated with conventional methods. The project involved several research elements, including treatment process evaluation, hydrodynamic flow and transport modeling, pilot testing at an uncontaminated site, and full-scale testing at a contaminated site. This report presents the results of the work at the contaminated site, X-701B at PORTS. Groundwater contamination at X-701B consists of trichloroethene (TCE) (concentrations up to 1800 mg/L) and technetium-998 (Tc{sup 99}) (activities up to 926 pCi/L).

Mevva ion source operated in purely gaseous mode

International Nuclear Information System (INIS)

Yushkov, G.Y.; MacGill, R.A.; Brown, I. G.

2003-01-01

We have operated a vacuum arc ion source in such a way as to form beams of purely gaseous ions. The vacuum arc configuration that is conventionally used to produce intense beams of metal ions was altered so as to form gaseous ion beams, with only minimal changes to the external circuitry and no changes at all internally to the ion source. In our experiments we formed beams from oxygen (O + and O 2 + ), nitrogen (N + and N 2 + ), argon (Ar + ) and carbon dioxide (C + , CO 2 + , O + and O 2 + ) at extraction voltage of 2 to 50 kV. We used a pulsed mode of operation, with beam pulses approximately 50 milliseconds long and repetition rate 10 pulses per second, for a duty cycle of about 50%. Downstream ion beam current as measured by a 5 cm diameter Faraday cup was typically 0.5 mA pulse or about 250 (micro)A time averaged. This time averaged beam current is very similar to that obtained for metal ions when the source is operated in the usual vacuum arc mode. Here we describe the modifications made to the source and the results of our investigations

Cyclotron production of radioactive gas from gaseous targets: inhomogeneity of the target activity - optimum flow rate of the carrier gas - cross sections

International Nuclear Information System (INIS)

Peters, J.-M.; Fiore, G. del; Quaglia, L.; Depresseux, J.-C.; Bartsch, P.

1979-01-01

When short-lived radioactive gases are produced by cyclotron-irradiated gaseous targets, the yield of activity, at the site of delivery, depends on the flow rate in the gas-carrying line. The authors improve a preliminarily published previous single model by the introduction of a supplementary hypothesis which takes into account the inhomogeneity of the activity in the gaseous target. By substituting the NTP volume of the gas in the irradiation cell Vsub(c) by a visible volume Vsub(a) depending on the flow rate and expressed by Vsub(a) = Vsub(infinity) +(V 0 - Vsub(infinity))exp(-kDsub(p)), they derive the following general expression for the optimum flow rate D which gives a maximum yield of production. D 2 -bD-bc-D 2 akexp(-kD)-abexp(-kD) = 0, a=lambda(V 0 -Vsub(infinity)), b = lambdaVsub(r), c = lambdaVsub(infinity), lambda = the decay constant of the radionuclide produced,Vsub(r) the inner volume of the gas-carrying line. The unknown parameters Vsub(r), Vsub(a), V 0 , Vsub(infinity), and k can be determined experimentally. The authors also suggest a new method for the determination of experimental cross sections with their gaseous target. (Auth.)

Determination of diffusion coefficients of carbon dioxide in water between 268 and 473 K in a high-pressure capillary optical cell with in situ Raman spectroscopic measurements

Science.gov (United States)

Lu, Wanjun; Guo, Huirong; Chou, I.-Ming; Burruss, R.C.; Li, Lanlan

2013-01-01

Accurate values of diffusion coefficients for carbon dioxide in water and brine at reservoir conditions are essential to our understanding of transport behavior of carbon dioxide in subsurface pore space. However, the experimental data are limited to conditions at low temperatures and pressures. In this study, diffusive transfer of carbon dioxide in water at pressures up to 45 MPa and temperatures from 268 to 473 K was observed within an optical capillary cell via time-dependent Raman spectroscopy. Diffusion coefficients were estimated by the least-squares method for the measured variations in carbon dioxide concentration in the cell at various sample positions and time. At the constant pressure of 20 MPa, the measured diffusion coefficients of carbon dioxide in water increase with increasing temperature from 268 to 473 K. The relationship between diffusion coefficient of carbon dioxide in water [D(CO2) in m2/s] and temperature (T in K) was derived with Speedy–Angell power-law approach as: D(CO2)=D0[T/Ts-1]m where D0 = 13.942 × 10−9 m2/s, Ts = 227.0 K, and m = 1.7094. At constant temperature, diffusion coefficients of carbon dioxide in water decrease with pressure increase. However, this pressure effect is rather small (within a few percent).

IAEA workshop and field trial at the Oak Ridge K-25 Site

International Nuclear Information System (INIS)

Hembree, D.M. Jr.; Ross, H.H.; Carter, J.A.

1995-03-01

In March 1994, members of the International Safeguards Department in the National Security Program Office (NSPO) hosted an environmental monitoring field trial workshop for International Atomic Energy Agency (IAEA) inspectors. The workshop was held at the Oak Ridge K-25 Site and its primary purpose was to train the inspectors in the techniques needed for effective environmental sample collection and handling. The workshop emphasized both sampling theory and practice. First, detailed techniques for swipe, vegetation, soil, biota, and water-associated sampling were covered in the classroom. Subsequently, the inspectors were divided into three groups for actual sample collection in and around the K-25 locale. The collected samples were processed by the Department of Energy (DOE) Network of Analytical Laboratories using established analytical techniques. This activity is part of the IAEA ''Programme 93+2 in. assessment of measures to enhance IAEA safeguards

Gaseous and particle emissions from an ethanol fumigated compression ignition engine

International Nuclear Information System (INIS)

Surawski, Nicholas C.; Ristovski, Zoran D.; Brown, Richard J.; Situ, Rong

2012-01-01

Highlights: ► Ethanol fumigation system fitted on a direct injection compression ignition engine. ► Ethanol substitutions up to 40% (by energy) were achieved. ► Gaseous and particle emissions were measured at intermediate speed. ► PM and NO emissions significantly reduced, whilst CO and HC increased. ► The number of particles emitted generally higher with ethanol fumigation. - Abstract: A 4-cylinder Ford 2701C test engine was used in this study to explore the impact of ethanol fumigation on gaseous and particle emission concentrations. The fumigation technique delivered vaporised ethanol into the intake manifold of the engine, using an injector, a pump and pressure regulator, a heat exchanger for vaporising ethanol and a separate fuel tank and lines. Gaseous (Nitric oxide (NO), Carbon monoxide (CO) and hydrocarbons (HC)) and particulate emissions (particle mass (PM 2.5 ) and particle number) testing was conducted at intermediate speed (1700 rpm) using 4 load settings with ethanol substitution percentages ranging from 10% to 40% (by energy). With ethanol fumigation, NO and PM 2.5 emissions were reduced, whereas CO and HC emissions increased considerably and particle number emissions increased at most test settings. It was found that ethanol fumigation reduced the excess air factor for the engine and this led to increased emissions of CO and HC, but decreased emissions of NO. PM 2.5 emissions were reduced with ethanol fumigation, as ethanol has a very low “sooting” tendency. This is due to the higher hydrogen-to-carbon ratio of this fuel, and also because ethanol does not contain aromatics, both of which are known soot precursors. The use of a diesel oxidation catalyst (as an after-treatment device) is recommended to achieve a reduction in the four pollutants that are currently regulated for compression ignition engines. The increase in particle number emissions with ethanol fumigation was due to the formation of volatile (organic) particles

Extending the Neuroanatomic Territory of Diffuse Midline Glioma, K27M Mutant: Pineal Region Origin.

Science.gov (United States)

Gilbert, Andrea R; Zaky, Wafik; Gokden, Murat; Fuller, Christine E; Ocal, Eylem; Leeds, Norman E; Fuller, Gregory N

2018-01-01

Diffuse midline glioma, H3-K27M mutant (DMG-K27M) is a newly described, molecularly distinct infiltrative glioma that almost exclusively arises in midline CNS structures, including the brain stem, especially the pons, as well as the thalamus and spinal cord with rare examples seen in the cerebellum, third ventricle, and hypothalamus. To our knowledge, only 1 case of a molecularly confirmed DMG-K27M arising in the pineal region has been previously reported. We present the second occurrence of a tissue-confirmed DMG-K27M of the pineal region, which, to our knowledge, is the first case reported in a child and the first case with documented preoperative MRI. This case, in addition to a prior report described in an adult, defines the lower end of a broad age range of DMG-K27M onset (12-65 years) and establishes the pineal gland as a bona fide site of origin for this newly codified midline glioma. © 2017 S. Karger AG, Basel.

Evaluations on Profiles of the Eddy Diffusion Coefficients through Simulations of Super Typhoons in the Northwestern Pacific

Directory of Open Access Journals (Sweden)

Jimmy Chi Hung Fung

2016-01-01

Full Text Available The modeling of the eddy diffusion coefficients (also known as eddy diffusivity in the first-order turbulence closure schemes is important for the typhoon simulations, since the coefficients control the magnitude of the sensible heat flux and the latent heat flux, which are energy sources for the typhoon intensification. Profiles of the eddy diffusion coefficients in the YSU planetary boundary layer (PBL scheme are evaluated in the advanced research WRF (ARW system. Three versions of the YSU scheme (original, K025, and K200 are included in this study. The simulation results are compared with the observational data from track, center sea-level pressure (CSLP, and maximum surface wind speed (MWSP. Comparing with the original version, the K200 improves the averaged mean absolute errors (MAE of track, CSLP, and MWSP by 6.0%, 3.7%, and 23.1%, respectively, while the K025 deteriorates the averaged MAEs of track, CSLP, and MWSP by 25.1%, 19.0%, and 95.0%, respectively. Our results suggest that the enlarged eddy diffusion coefficients may be more suitable for super typhoon simulations.

D/H diffusion in serpentine

Science.gov (United States)

Pilorgé, Hélène; Reynard, Bruno; Remusat, Laurent; Le Floch, Sylvie; Montagnac, Gilles; Cardon, Hervé

2017-08-01

Interactions between aqueous fluids and ultrabasic rocks are essential processes in a broad range of contexts including hydrothermal alteration on the parent body of carbonaceous chondrites, at mid-oceanic ridge, and in subduction zones. Tracking these processes and understanding reaction kinetics require knowledge of the diffusion of water in rocks, and of isotope fractionation in major minerals forming under hydrous conditions, such as serpentines. We present a study of D/H inter-diffusion in antigorite, a common variety of serpentine. Experiments were performed in a belt apparatus at 315 °C, 450 °C and 540 °C and at 3.0 GPa on natural antigorite powders saturated with interstitial D2O. An experiment was performed in a diamond anvil cell at 350 °C and 2.5 GPa on an antigorite single-crystal loaded with pure D2O. D/(D + H) ratios were mapped using Raman spectroscopy for the experiments at 315 °C, 450 °C and 540 °C and by NanoSIMS for the experiment at 350 °C. As antigorite is a phyllosilicate, diffusion coefficients were obtained for crystallographic directions parallel and perpendicular to the silicate layers (perpendicular and parallel to the c∗-axis, respectively). Arrhenius relations for D/H inter-diffusion coefficients were determined to be DD/H (m2/s) = 4.71 × 10-2 × exp(-207(-33/+58) (kJ/mol)/RT) and DD/H (m2/s) = 1.61 × 10-4 × exp(-192(-34/+93) (kJ/mol)/RT) perpendicular and parallel to the c∗-axis, respectively, and DD/H (m2/s) = 7.09 × 10-3 × exp(-202(-33/+70) (kJ/mol)/RT) for the bulk diffusivity. Assuming D/H inter-diffusion coefficients for antigorite are the same for all serpentine species, closure temperature and diffusion durations are applied to hydrothermal alteration in the oceanic lithosphere, and in CI, CM and CR chondrites. Closure temperatures lie below 300 °C for terrestrial hydrothermal alteration and depend on serpentine variety because they have different typical grain sizes. Closure temperatures lie below 160 °C for

Dielectrophoretic separation of gaseous isotopes

International Nuclear Information System (INIS)

McConnell, D.B.

1976-01-01

This invention relates to a process for the separation of gaseous isotopes by electrophoresis assisted by convective countercurrent flow and to an apparatus for use in the process. The invention is especially applicable to heavy water separation from steam; however, it is to be understood that the invention is broadly applicable to the separation of gaseous isotopes having different dipole moments and/or different molecular weights. (author)

Diffusing diffusivity: Rotational diffusion in two and three dimensions

Science.gov (United States)

Jain, Rohit; Sebastian, K. L.

2017-06-01

We consider the problem of calculating the probability distribution function (pdf) of angular displacement for rotational diffusion in a crowded, rearranging medium. We use the diffusing diffusivity model and following our previous work on translational diffusion [R. Jain and K. L. Sebastian, J. Phys. Chem. B 120, 3988 (2016)], we show that the problem can be reduced to that of calculating the survival probability of a particle undergoing Brownian motion, in the presence of a sink. We use the approach to calculate the pdf for the rotational motion in two and three dimensions. We also propose new dimensionless, time dependent parameters, αr o t ,2 D and αr o t ,3 D, which can be used to analyze the experimental/simulation data to find the extent of deviation from the normal behavior, i.e., constant diffusivity, and obtain explicit analytical expressions for them, within our model.

Refurbishment of uranium hexafluoride cylinder storage yards C-745-K, L, M, N, and P and construction of a new uranium hexafluoride cylinder storage yard (C-745-T) at the Paducah Gaseous Diffusion Plant, Paducah, Kentucky

International Nuclear Information System (INIS)

1996-07-01

The Paducah Gaseous Diffusion Plant (PGDP) is a uranium enrichment facility owned by the US Department of Energy (DOE). A residual of the uranium enrichment process is depleted uranium hexafluoride (UF6). Depleted UF6, a solid at ambient temperature, is stored in 32,200 steel cylinders that hold a maximum of 14 tons each. Storage conditions are suboptimal and have resulted in accelerated corrosion of cylinders, increasing the potential for a release of hazardous substances. Consequently, the DOE is proposing refurbishment of certain existing yards and construction of a new storage yard. This environmental assessment (EA) evaluates the impacts of the proposed action and no action and considers alternate sites for the proposed new storage yard. The proposed action includes (1) renovating five existing cylinder yards; (2) constructing a new UF6 storage yard; handling and onsite transport of cylinders among existing yards to accommodate construction; and (4) after refurbishment and construction, restacking of cylinders to meet spacing and inspection requirements. Based on the results of the analysis reported in the EA, DOE has determined that the proposed action is not a major Federal action that would significantly affect the quality of the human environment within the context of the National Environmental Policy Act of 1969. Therefore, DOE is issuing a Finding of No Significant Impact. Additionally, it is reported in this EA that the loss of less than one acre of wetlands at the proposed project site would not be a significant adverse impact

Refurbishment of uranium hexafluoride cylinder storage yards C-745-K, L, M, N, and P and construction of a new uranium hexafluoride cylinder storage yard (C-745-T) at the Paducah Gaseous Diffusion Plant, Paducah, Kentucky

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-07-01

The Paducah Gaseous Diffusion Plant (PGDP) is a uranium enrichment facility owned by the US Department of Energy (DOE). A residual of the uranium enrichment process is depleted uranium hexafluoride (UF6). Depleted UF6, a solid at ambient temperature, is stored in 32,200 steel cylinders that hold a maximum of 14 tons each. Storage conditions are suboptimal and have resulted in accelerated corrosion of cylinders, increasing the potential for a release of hazardous substances. Consequently, the DOE is proposing refurbishment of certain existing yards and construction of a new storage yard. This environmental assessment (EA) evaluates the impacts of the proposed action and no action and considers alternate sites for the proposed new storage yard. The proposed action includes (1) renovating five existing cylinder yards; (2) constructing a new UF6 storage yard; handling and onsite transport of cylinders among existing yards to accommodate construction; and (4) after refurbishment and construction, restacking of cylinders to meet spacing and inspection requirements. Based on the results of the analysis reported in the EA, DOE has determined that the proposed action is not a major Federal action that would significantly affect the quality of the human environment within the context of the National Environmental Policy Act of 1969. Therefore, DOE is issuing a Finding of No Significant Impact. Additionally, it is reported in this EA that the loss of less than one acre of wetlands at the proposed project site would not be a significant adverse impact.

Diffusion of 51Cr along high-diffusivity paths in Ni-Fe alloys

International Nuclear Information System (INIS)

Cermak, J.

1990-01-01

Penetration profiles of 51 Cr in polycrystalline alloys Ni-xFe (x = 0, 20, 40, and 60 wt.% Fe) after diffusion anneals at temperatures between 693 and 1473 K are studied. Sectioning of diffusion zones of samples annealed above 858 K is carried out by grinding, at lower temperatures by DC glow discharge sputtering. The concentration of 51 Cr in depth x is assumed to be proportional to relative radioactivity of individual sections. With help of volume and pipe self-diffusion data taken from literature, the temperature dependence of product P = δD g (δ and D g are grain boundary width and grain boundary diffusion coefficient, respectively) is obtained: P = (2.68 - 0.88 +1.3 ) x 10 -11 exp [-(221.3 ± 3.0) kJ/mol/RT]m 3 /s. This result agrees well with the previous measurements of 51 Cr diffusivity in Fe-18 Cr-12 Ni and Fe-21 Cr-31 Ni. It indicates that the mean chemical composition of Fe-Cr-Ni ternary alloys is not a dominant factor affecting the grain boundary diffusivity of Cr in these alloys. (author)

Melting curve of helium from 4 to 25 K

Energy Technology Data Exchange (ETDEWEB)

Krause, J K; Swenson, C A [Ames Lab., Iowa (USA)

1976-07-01

New data for the melting curve of He/sup 4/ for temperatures between 4 and 25 K agree with earlier results by Mills and Grilly (Phys. Rev.; 99:480 (1955)) and by Crawford and Daniels (J. Chem. Phys.; 55:5651 (1971)), but disagree with the relationship given by Glassford and Smith (Cryogenics; 6:193 (1966) who carried out equation of state studies on fluid and solid He/sup 4/. The reasons for the disagreement are not clear, but can be interpreted in terms of temperature scale inaccuracies which could have influenced all of their results.

Hydrogen and Gaseous Fuel Safety and Toxicity

Energy Technology Data Exchange (ETDEWEB)

Lee C. Cadwallader; J. Sephen Herring

2007-06-01

Non-traditional motor fuels are receiving increased attention and use. This paper examines the safety of three alternative gaseous fuels plus gasoline and the advantages and disadvantages of each. The gaseous fuels are hydrogen, methane (natural gas), and propane. Qualitatively, the overall risks of the four fuels should be close. Gasoline is the most toxic. For small leaks, hydrogen has the highest ignition probability and the gaseous fuels have the highest risk of a burning jet or cloud.

Fuel rich and fuel lean catalytic combustion of the stabilized confined turbulent gaseous diffusion flames over noble metal disc burners

Directory of Open Access Journals (Sweden)

Amal S. Zakhary

2014-03-01

Full Text Available Catalytic combustion of stabilized confined turbulent gaseous diffusion flames using Pt/Al2O3 and Pd/Al2O3 disc burners situated in the combustion domain under both fuel-rich and fuel-lean conditions was experimentally studied. Commercial LPG fuel having an average composition of: 23% propane, 76% butane, and 1% pentane was used. The thermal structure of these catalytic flames developed over Pt/Al2O3 and Pd/Al2O3 burners were examined via measuring the mean temperature distribution in the radial direction at different axial locations along the flames. Under-fuel-rich condition the flames operated over Pt catalytic disc attained high temperature values in order to express the progress of combustion and were found to achieve higher activity as compared to the flames developed over Pd catalytic disc. These two types of catalytic flames demonstrated an increase in the reaction rate with the downstream axial distance and hence, an increase in the flame temperatures was associated with partial oxidation towards CO due to the lack of oxygen. However, under fuel-lean conditions the catalytic flame over Pd catalyst recorded comparatively higher temperatures within the flame core in the near region of the main reaction zone than over Pt disc burner. These two catalytic flames over Pt and Pd disc burners showed complete oxidation to CO2 since the catalytic surface is covered by more rich oxygen under the fuel-lean condition.

Angular resolution of the gaseous micro-pixel detector Gossip

Science.gov (United States)

Bilevych, Y.; Blanco Carballo, V.; van Dijk, M.; Fransen, M.; van der Graaf, H.; Hartjes, F.; Hessey, N.; Koppert, W.; Nauta, S.; Rogers, M.; Romaniouk, A.; Veenhof, R.

2011-06-01

Gossip is a gaseous micro-pixel detector with a very thin drift gap intended for a high rate environment like at the pixel layers of ATLAS at the sLHC. The detector outputs not only the crossing point of a traversing MIP, but also the angle of the track, thus greatly simplifying track reconstruction. In this paper we describe a testbeam experiment to examine the angular resolution of the reconstructed track segments in Gossip. We used here the low diffusion gas mixture DME/CO 2 50/50. An angular resolution of 20 mrad for perpendicular tracks could be obtained from a 1.5 mm thin drift volume. However, for the prototype detector used at the testbeam experiment, the resolution of slanting tracks was worsened by poor time resolution of the pixel chip used.

Angular resolution of the gaseous micro-pixel detector Gossip

Energy Technology Data Exchange (ETDEWEB)

Bilevych, Y.; Blanco Carballo, V.; Dijk, M. van; Fransen, M.; Graaf, H. van der; Hartjes, F.; Hessey, N.; Koppert, W.; Nauta, S. [Nikhef, P.O. Box 41882, 1009 DB Amsterdam (Netherlands); Rogers, M. [Radboud University, P.O. Box 9102, 6500HC Nijmegen (Netherlands); Romaniouk, A.; Veenhof, R. [CERN, CH-1211, Geneve 23 (Switzerland)

2011-06-15

Gossip is a gaseous micro-pixel detector with a very thin drift gap intended for a high rate environment like at the pixel layers of ATLAS at the sLHC. The detector outputs not only the crossing point of a traversing MIP, but also the angle of the track, thus greatly simplifying track reconstruction. In this paper we describe a testbeam experiment to examine the angular resolution of the reconstructed track segments in Gossip. We used here the low diffusion gas mixture DME/CO{sub 2} 50/50. An angular resolution of 20 mrad for perpendicular tracks could be obtained from a 1.5 mm thin drift volume. However, for the prototype detector used at the testbeam experiment, the resolution of slanting tracks was worsened by poor time resolution of the pixel chip used.

Angular resolution of the gaseous micro-pixel detector Gossip

International Nuclear Information System (INIS)

Bilevych, Y.; Blanco Carballo, V.; Dijk, M. van; Fransen, M.; Graaf, H. van der; Hartjes, F.; Hessey, N.; Koppert, W.; Nauta, S.; Rogers, M.; Romaniouk, A.; Veenhof, R.

2011-01-01

Gossip is a gaseous micro-pixel detector with a very thin drift gap intended for a high rate environment like at the pixel layers of ATLAS at the sLHC. The detector outputs not only the crossing point of a traversing MIP, but also the angle of the track, thus greatly simplifying track reconstruction. In this paper we describe a testbeam experiment to examine the angular resolution of the reconstructed track segments in Gossip. We used here the low diffusion gas mixture DME/CO 2 50/50. An angular resolution of 20 mrad for perpendicular tracks could be obtained from a 1.5 mm thin drift volume. However, for the prototype detector used at the testbeam experiment, the resolution of slanting tracks was worsened by poor time resolution of the pixel chip used.

Mutual diffusion coefficients of L-glutamic acid and monosodium L-glutamate in aqueous solutions at T = 298.15 K

International Nuclear Information System (INIS)

Ribeiro, Ana C.F.; Rodrigo, M.M.; Barros, Marisa C.F.; Verissimo, Luis M.P.; Romero, Carmen; Valente, Artur J.M.; Esteso, Miguel A.

2014-01-01

Highlights: • Interdiffusion coefficients of L-glutamic acid and sodium L-glutamate were measured. • The L-glutamic acid behaves as a monoprotic weak acid. • The sodium L-glutamate shows a symmetrical 1:1 non-associated behaviour. • Limiting diffusion coefficients and ionic conductivities were estimated. • Diffusion coefficients were discussed on the basis of the Onsager–Fuoss equations. - Abstract: Mutual diffusion coefficient values for binary aqueous solutions of both L-glutamic acid (H 2 Glu) and sodium L-glutamate (NaHGlu) were measured with the Taylor dispersion technique, at T = 298.15 K, and concentrations ranging from (0.001 to 0.100) mol · dm −3 . The results were discussed on the basis of the Onsager–Fuoss and the Nernst theoretical equations, by considering the H 2 Glu as a weak acid (monoprotic acid, with K 2 = 5.62 · 10 −5 ). The smaller values found for the acid with respect to those of the salt, confirm this association hypothesis. From the diffusion coefficient values at infinitesimal concentration, limiting ionic conductivities as well as the hydrodynamic radius of the hydrogen glutamate ion (HGlu − ) were derived and analyzed in terms of the chain methylene groups. The effect of different phenomena, such as association or complexation, were also taken into consideration and discussed. Values for the dissociation degree for H 2 Glu were also estimated

Preparation of standard mixtures of gas hydrocarbons in air by the diffusion dilution method

International Nuclear Information System (INIS)

Garcia, M. R.; Perez, M. M.

1979-01-01

An original diffusion system able to produce continuously gaseous samples is described. This system can generate samples with concentrations of benzene in air from 0.1 to 1 ppm a reproducible way. The diffusion dilution method used Is also studied. The use of this diffusion system has been extended to the preparation of binary mixtures (benzene-toluene). Whit a secondary dilution device is possible preparing these mixtures over a wide range of concentrations (0.11 to 0.04 ppm for benzene and 0.06 to 0.02 for toluene). (Author) 7 refs

Novel mass spectrometric instrument for gaseous and particulate characterization and monitoring

International Nuclear Information System (INIS)

Coggiola, M.J.

1994-02-01

SRI International will develop a unique new instrument that will be capable of providing real-time (<1 minute), quantitative, chemical characterization of gaseous and particulate pollutants generated from DOE waste cleanup activities. The instrument will be capable of detecting and identifying volatile organic compounds, polynuclear aromatic hydrocarbons, heavy metals, and transuranic species released during waste cleanup activities. The instrument will be unique in its ability to detect and quantify in real-time these diverse pollutants in both vapor and particulate form. The instrument to be developed under this program will consist of several major components: (1) an isokinetic sampler capable of operating over a wide range of temperatures (up to 500 K) and flow rates; (2) a high pressure to low pressure transition and sampling region that efficiently separates particles from vapor-phase components for separate, parallel analyses; (3) two small mass spectrometers, one optimized for organic analysis using a unique field ionization source and one optimized for particulate characterization using thermal pyrolysis and electron-impact ionization (EI); and (4) a powerful personal computer for control and data acquisition. Initially, the instrument will be developed for targeted use in conjunction with the K-1435 Toxic Substances Control Act (TSCA) incinerator at the Oak Ridge National Laboratory K-25 site. Ultimately, the instrument will be designed to operate in the field at any cleanup site, located close to the stack or process vent, providing the plant operations personnel with real-time information and alarm capabilities. In addition, this instrument will be very broadly applicable for cleanup or sampling, for example, any time contaminated soil is moved or disturbed

Strategies to reduce gaseous KCl and chlorine in deposits during combustion of biomass in fluidised bed boilers

Energy Technology Data Exchange (ETDEWEB)

Kassman, Haakan

2012-11-01

Combustion of a biomass with an enhanced content of alkali and chlorine (Cl) can result in operational problems including deposit formation and superheater corrosion. The strategies applied to reduce such problems include co-combustion and the use of additives. In this work, measures were investigated in order to decrease the risk of superheater corrosion by reducing gaseous KCl and the content of chlorine in deposits. The strategies applied were sulphation of KCl by sulphur/sulphate containing additives (i.e. elemental sulphur (S) and ammonium sulphate (AS)) and co-combustion with peat. Both sulphation of KCl and capture of potassium (K) in ash components can be of importance when peat is used. The experiments were mainly performed in a 12 MW circulation fluidised bed (CFB) boiler equipped for research purposes but also in a full-scale CFB boiler. The results were evaluated by means of IACM (on-line measurements of gaseous KCl), conventional gas analysis, deposit and corrosion probe measurements and ash analysis. Ammonium sulphate performed significantly better than elemental sulphur. Thus the presence of SO{sub 3} (i.e. AS) is of greater importance than that of SO{sub 2} (i.e. S) for sulphation of gaseous KCl and reduction of chlorine in deposits. Only a minor reduction of gaseous KCl was obtained during co-combustion with peat although chlorine in the deposits was greatly reduced. This reduction was supposedly due to capture of K by reactive components from the peat ash in parallel to sulphation of KCl. These compounds remained unidentified. The effect of volatile combustibles on the sulphation of gaseous KCl was investigated. The poorest sulphation was attained during injection of ammonium sulphate in the upper part of the combustion chamber during the lowest air excess ratio. The explanation for this is that SO{sub 3} was partly consumed by side reactions due to the presence of combustibles. These experimental results were supported by modelling, although the

Positron annihilation lifetime spectroscopy (PALS) application in metal barrier layer integrity for porous low- k materials

CERN Document Server

Simon, Lin; Gidley, D W; Wetzel, J T; Monnig, K A; Ryan, E T; Simon, Jang; Douglas, Yu; Liang, M S; En, W G; Jones, E C; Sturm, J C; Chan, M J; Tiwari, S C; Hirose, M

2002-01-01

Positron Annihilation Lifetime Spectroscopy (PALS) is a useful tool to pre-screen metal barrier integrity for Si-based porous low-k dielectrics. Pore size of low-k, thickness of metal barrier Ta, positronium (Ps) leakage from PALS, trench sidewall morphology, electrical test from one level metal (1LM) pattern wafer and Cu diffusion analysis were all correlated. Macro-porous low-k (pore size >=200 AA) and large scale meso-porous low-k (>50~200 AA) encounter both Ps leakage and Cu diffusion into low-k dielectric in the 0.25 mu mL/0.3 mu mS structures when using SEMATECH in-house PVD Ta 250 AA as barrier layer. For small scale meso-porous (>20~50 AA) and micro- porous (<=20 AA) low-k, no Ps leakage and no Cu diffusion into low-k were observed even with PVD Ta 50 AA, which is proved also owing to sidewall densification to seal all sidewall pores due to plasma etch and ash. For future technology, smaller pore size of porous Si-based low-k (=<50 AA) will be preferential for dense low-k like trench sidewall to...

Biodegradation polyurethane derived from vegetable oil irradiated with gamma rays 25 kGy and 100 kGy

International Nuclear Information System (INIS)

Santos, Antonia M. dos; Claro Neto, Salvador; Azevedo, Elaine C. de

2011-01-01

The environment requires polymers that can be degraded by the action of microorganisms. In this work was studied the biodegradation of polyurethane samples derived from vegetable oil (castor oil), which were irradiated with gamma rays 25 kGy and 100 kGy compared with the same polyurethane without being irradiated. Biodegradation of polyurethane was carried out in culture medium containing the fungus Aspergillus niger by 146 days and the result was evaluated using the technique of thermogravimetric analysis, where there was a change of behavior of the curves TGA / DTG occurred indicating that chemical modifications of molecules present in the structure of the polymer chain, thus confirming that the material has undergone the action of microorganisms. (author)

Gaseous ligand selectivity of the H-NOX sensor protein from Shewanella oneidensis and comparison to those of other bacterial H-NOXs and soluble guanylyl cyclase.

Science.gov (United States)

Wu, Gang; Liu, Wen; Berka, Vladimir; Tsai, Ah-Lim

2017-09-01

To delineate the commonalities and differences in gaseous ligand discrimination among the heme-based sensors with Heme Nitric oxide/OXygen binding protein (H-NOX) scaffold, the binding kinetic parameters for gaseous ligands NO, CO, and O 2 , including K D , k on , and k off , of Shewanella oneidensis H-NOX (So H-NOX) were characterized in detail in this study and compared to those of previously characterized H-NOXs from Clostridium botulinum (Cb H-NOX), Nostoc sp. (Ns H-NOX), Thermoanaerobacter tengcongensis (Tt H-NOX), Vibrio cholera (Vc H-NOX), and human soluble guanylyl cyclase (sGC), an H-NOX analogue. The K D (NO) and K D (CO) of each bacterial H-NOX or sGC follow the "sliding scale rule"; the affinities of the bacterial H-NOXs for NO and CO vary in a small range but stronger than those of sGC by at least two orders of magnitude. On the other hand, each bacterial H-NOX exhibits different characters in the stability of its 6c NO complex, reactivity with secondary NO, stability of oxyferrous heme and autoxidation to ferric heme. A facile access channel for gaseous ligands is also identified, implying that ligand access has only minimal effect on gaseous ligand selectivity of H-NOXs or sGC. This comparative study of the binding parameters of the bacterial H-NOXs and sGC provides a basis to guide future new structural and functional studies of each specific heme sensor with the H-NOX protein fold. Copyright © 2017 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

Study on the surface oxidation of uranium in different gaseous atmospheres

International Nuclear Information System (INIS)

Wang Xiaoling; Fu Yibei; Xie Renshou

1996-03-01

The studying for the surface oxidation of uranium and oxide by X-ray photoelectron spectroscopy (XPS), Auger electron spectroscopy (AES), secondary ion mass spectroscopy (SIMS), and the surface oxidation of uranium in different gaseous atmospheres such as O 2 , H 2 , CO, CO 2 , H 2 O(v) and air were reviewed. The surface oxidation of uranium is greatly influenced by a number of parameters including atmospheric temperature, pressure, diffusion of adsorbed gas atoms through the oxide layer, surface and interface chemical component, and defect structure and electron nature of the oxide layer. The initial oxidation mechanism and kinetics have been discussed. Suggestions for future work have also been presented. (32 refs., 7 figs., 5 tabs.)

Ternary mutual diffusion of isoniazid in aqueous sodium chloride, sodium hydroxide, and hydrochloric acid at T = 298.15 K

Energy Technology Data Exchange (ETDEWEB)

Ribeiro, Ana C.F., E-mail: anacfrib@ci.uc.p [Department of Chemistry, University of Coimbra, 3004-535 Coimbra (Portugal); Santos, Ana C.G., E-mail: anacatarinasantos123@gmail.co [Department of Chemistry, University of Coimbra, 3004-535 Coimbra (Portugal); Lobo, Victor M.M., E-mail: vlobo@ci.uc.p [Department of Chemistry, University of Coimbra, 3004-535 Coimbra (Portugal); Sobral, Abilio J.F.N., E-mail: asobral@ci.uc.p [Department of Chemistry, University of Coimbra, 3004-535 Coimbra (Portugal); Cabral, Ana M.T.D.P.V., E-mail: acabral@ff.uc.p [Faculty of Pharmacy, University of Coimbra, 3000-295 Coimbra (Portugal); Esteso, Miguel A., E-mail: miguel.esteso@uah.e [Departamento de Quimica Fisica, Facultad de Farmacia, Universidad de Alcala, 28871 Alcala de Henares, Madrid (Spain)

2010-07-15

Ternary mutual diffusion coefficients measured by Taylor dispersion method (D{sub 11}, D{sub 22}, D{sub 12}, and D{sub 21}) are reported for aqueous solutions containing isoniazid and different electrolytes (NaCl, NaOH, or HCl) at T = 298.15 K at different carrier concentrations. These diffusion coefficients have been measured having in mind a better understanding of the structure of these systems and the thermodynamic behaviour of isoniazid in different media. For example, it is possible to make conclusions about the influence of these electrolytes in diffusion of isoniazid, and to obtain information concerning the number of moles of each component transported per mole of the other component driven by its own concentration gradient.

A 25kW fiber-coupled diode laser for pumping applications

Science.gov (United States)

Malchus, Joerg; Krause, Volker; Koesters, Arnd; Matthews, David G.

2014-03-01

In this paper we report the development of a new fiber-coupled diode laser for pumping applications capable of generating 25 kW with four wavelengths. The delivery fiber has 2.0 mm core diameter and 0.22 NA resulting in a Beam Parameter Product (BPP) of 220 mm mrad. To achieve the specifications mentioned above a novel beam transformation technique has been developed combining two high power laser stacks in one common module. After fast axis collimation and beam reformatting a beam with a BPP of 200 mm mrad x 40 mm mrad in the slow and fast-axis is generated. Based on this architecture a customer-specific pump laser with 25 kW optical output power has been developed, in which two modules are polarization multiplexed for each wavelength (980nm, 1020nm, 1040m and 1060nm). After slow-axis collimation these wavelengths are combined using dense wavelength coupling before focusing onto the fiber endface. This new laser is based on a turn-key platform, allowing straight-forward integration into any pump application. The complete system has a footprint of less than 1.4m² and a height of less than 1.8m. The laser diodes are water cooled, achieve a wall-plug efficiency of up to 60%, and have a proven lifetime of <30,000 hours. The new beam transformation techniques open up prospects for the development of pump sources with more than 100kW of optical output power.

Gaseous fuel reactors for power systems

Science.gov (United States)

Kendall, J. S.; Rodgers, R. J.

1977-01-01

Gaseous-fuel nuclear reactors have significant advantages as energy sources for closed-cycle power systems. The advantages arise from the removal of temperature limits associated with conventional reactor fuel elements, the wide variety of methods of extracting energy from fissioning gases, and inherent low fissile and fission product in-core inventory due to continuous fuel reprocessing. Example power cycles and their general performance characteristics are discussed. Efficiencies of gaseous fuel reactor systems are shown to be high with resulting minimal environmental effects. A technical overview of the NASA-funded research program in gaseous fuel reactors is described and results of recent tests of uranium hexafluoride (UF6)-fueled critical assemblies are presented.

3.55 GeV/c Kp elastic scattering near 180 deg; Diffusion elastique des K de 3.55 GeV/C par les protons, au voisinage de 180 deg

Energy Technology Data Exchange (ETDEWEB)

Duflo, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1969-07-01

Backward elastic K{sup +}p and K{sup -}p scattering has been measured in the angular interval 168 deg. < {theta}.c.m. < 177 deg. The experimental apparatus included optical spark chambers to measure the three prongs of the event scattering, a set of scintillation counters and Cerenkov counters to select events ant trigger chambers, and a magnet to determine the moment of the recoil proton. 106000 photographs was taken. Of these, 22 satisfied all requirements as elastic K{sup +}p scattering events. No event was found satisfy the kinematical criteria for K{sup -}p elastic scattering. The correspondent values of differential cross sections are: (d{sigma}/d{omega})K{sup +}p {yields} pK{sup +} = 17 {+-} 4 {mu}b/ster. (d{sigma}/d{omega})K{sup -}p {yields} pK{sup -} {<=} 0.6 {mu}b/ster. Contaminations by {pi}p backward scattering, and inelastic scattering were estimated. Elastic scattering K{sup +}p exhibits a backward peak. A reasonably satisfactory interpretation of our results is obtained by exchange models. There is, in fact, no definitely established particles which could intermediate the Kp{sup -} {yields} pK{sup -} process in exchange cannel. That is in good agreement with our small value of K{sup -}p backward elastic scattering cross section. Our results lend support to the conclusions of the interference model developed by Barger and Cline for the {pi}p backward scattering, and to qualitative previsions of the Quark models. (author) [French] La diffusion elastique en arriere des K{sup +} et K{sup -} par les protons a ete mesuree dans l'intervalle angulaire 168 deg. < {theta}cm < 177 deg. Le dispositif experimental comprenait des chambres a etincelles 'optiques' pour mesurer les trois trajectoires de l'evenement diffuse, un ensemble de compteurs a scintillations et de compteurs Cerenkov pour selectionner les evenements et declencher les chambres, et un aimant pour determiner le moment du proton de recul. 106000 photographies ont ete prises, dont 22 ont satisfait a

3.55 GeV/c Kp elastic scattering near 180 deg; Diffusion elastique des K de 3.55 GeV/C par les protons, au voisinage de 180 deg

Energy Technology Data Exchange (ETDEWEB)

Duflo, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1969-07-01

Backward elastic K{sup +}p and K{sup -}p scattering has been measured in the angular interval 168 deg. < {theta}.c.m. < 177 deg. The experimental apparatus included optical spark chambers to measure the three prongs of the event scattering, a set of scintillation counters and Cerenkov counters to select events ant trigger chambers, and a magnet to determine the moment of the recoil proton. 106000 photographs was taken. Of these, 22 satisfied all requirements as elastic K{sup +}p scattering events. No event was found satisfy the kinematical criteria for K{sup -}p elastic scattering. The correspondent values of differential cross sections are: (d{sigma}/d{omega})K{sup +}p {yields} pK{sup +} = 17 {+-} 4 {mu}b/ster. (d{sigma}/d{omega})K{sup -}p {yields} pK{sup -} {<=} 0.6 {mu}b/ster. Contaminations by {pi}p backward scattering, and inelastic scattering were estimated. Elastic scattering K{sup +}p exhibits a backward peak. A reasonably satisfactory interpretation of our results is obtained by exchange models. There is, in fact, no definitely established particles which could intermediate the Kp{sup -} {yields} pK{sup -} process in exchange cannel. That is in good agreement with our small value of K{sup -}p backward elastic scattering cross section. Our results lend support to the conclusions of the interference model developed by Barger and Cline for the {pi}p backward scattering, and to qualitative previsions of the Quark models. (author) [French] La diffusion elastique en arriere des K{sup +} et K{sup -} par les protons a ete mesuree dans l'intervalle angulaire 168 deg. < {theta}cm < 177 deg. Le dispositif experimental comprenait des chambres a etincelles 'optiques' pour mesurer les trois trajectoires de l'evenement diffuse, un ensemble de compteurs a scintillations et de compteurs Cerenkov pour selectionner les evenements et declencher les chambres, et un aimant pour determiner le moment du proton de recul. 106000 photographies ont ete prises

Calibration procedure of Hukseflux SR25 to Establish the Diffuse Reference for the Outdoor Broadband Radiometer Calibration

Energy Technology Data Exchange (ETDEWEB)

Reda, Ibrahim M. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Andreas, Afshin M. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

2017-08-01

Accurate pyranometer calibrations, traceable to internationally recognized standards, are critical for solar irradiance measurements. One calibration method is the component summation method, where the pyranometers are calibrated outdoors under clear sky conditions, and the reference global solar irradiance is calculated as the sum of two reference components, the diffuse horizontal and subtended beam solar irradiances. The beam component is measured with pyrheliometers traceable to the World Radiometric Reference, while there is no internationally recognized reference for the diffuse component. In the absence of such a reference, we present a method to consistently calibrate pyranometers for measuring the diffuse component. The method is based on using a modified shade/unshade method and a pyranometer with less than 0.5 W/m2 thermal offset. The calibration result shows that the responsivity of Hukseflux SR25 pyranometer equals 10.98 uV/(W/m2) with +/-0.86 percent uncertainty.

Final report on the key comparison CCPR-K5: Spectral diffuse reflectance

Science.gov (United States)

Nadal, Maria; Eckerle, Kenneth L.; Early, Edward A.; Ohno, Yoshi

2013-01-01

The CCPR K5 key comparison on spectral diffuse reflectance was carried out in the framework of the CIPM Mutual Recognition Arrangement, by 13 national metrology institutes (MMIs) as participants. The participants were CSIR-NML (South Africa), HUT (Finland), IFA-CSIC (Spain), KRISS (Republic of Korea), MSL (New Zealand), NIM (China), NIST (United States of America), NMIJ (Japan), NPL (United Kingdom), NRC (Canada), OMH (Hungary), PTB (Germany) and VNIIOFI (Russia Federation). NIST (USA) piloted the comparison. The aim of this comparison was to check the agreement of measurement of the spectral diffuse reflectance among participants, using the measurement geometry of d/0 or 0/d in the wavelength range of 360 nm to 820 nm at 20 nm increment. The comparison was a star type comparison with the samples provided by the pilot laboratory and with the measurement sequence: Pilot-Participant-Pilot. Spectralon and matte white ceramic tiles were used as the transfer standards. Each participant received three of each type of sample and at least one sample of each type was measured three times on three separate days, and the other two samples were measured once. The report presents the description of the measurement facilities, procedures and uncertainties of all the participants as well as the results of the comparison. Measurement results from the participants and their associated uncertainties were analyzed in accordance with the Guidelines for CCPR Key Comparison Report Preparation, using weighted mean with cut-off. For the calculation of the Key Comparison Reference Value (KCRV), as agreed by the participants, the data of both samples were used for the 460 nm to 820 nm region and only the data of the Spectralon samples were used in the spectral region of 360 nm to 440 nm. The unilateral degrees of equivalence (DoE) calculated for each participant are mostly consistent within the uncertainty (k = 2) of the DoE. This international comparison of spectral diffuse reflectance

Thermal properties of Permian Basin evaporites to 493 K and 30 MPa confining pressure

International Nuclear Information System (INIS)

Durham, W.B.; Heard, H.C.; Boro, C.O.; Keller, K.T.; Ralph, W.E.; Trimmer, D.A.

1987-01-01

Laboratory measurements have been made of the thermal conductivity and diffusivity of four rock salts, two anhydrites, and two dolomites bordering the Cycle 4 and Cycle 5 bedded salt formations in the Permian Basin in Deaf Smith County, Texas. Measurement conditions ranged from 303 to 473 K in temperature, and 0.1 to 31.0 MPa in hydrostatic confining pressure. Within the +-5% measurement resolution neither conductivity nor diffusivity showed a dependence upon pressure in any of the rocks. Conductivity and diffusivity in all rocks had a negative temperature dependence. For the two Cycle 4 salt samples, conductivity over the temperature range explored fell from 5.5 to 3.75 W/m.K, and diffusivity fell from about 2.7 to 1.7 x 10 -6 m 2 /s. One of the Cycle 5 salts was a single crystal which had anomalous results, but the other had a low conductivity, about 3.4 W/m.K, with very weak temperature dependence, and a high diffusivity, 3.8 to 2.5 x 10 -6 m 2 /s over the temperature range. In the nonsalts, conductivity and diffusivity decreased 10 to 20% over the temperature range explored, which was 308 -6 m 2 /s for the anhydrites and 1.4 x 10 -6 m 2 /s for both the dolomites. The coefficient of thermal linear expansion was measured for the Cycle 5 salt and nonsalts over 308 -6 K -1 at P = 3.0 MPa to 4 x 10 -6 K -1 at P = 30 MPa for both nonsalt rocks. In anhydrite, it decreased with increasing temperature at a rate of roughly 5 x 10 -8 K -2 at all pressures. In dolomite, the coefficient increased at roughly the same rate. Expansion of the salt ranged from 33 to 38 x 10 -6 K -1 and was independent of pressure and temperature

A robust and stable PLC based control system for 40kJ/25kV EMM system

Energy Technology Data Exchange (ETDEWEB)

Sharma, Vijay; Saroj, P.C.; Kulkarni, M.R.; Kumar, Satendra, E-mail: vijay9819420563@gmail.com [Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Mumbai (India)

2014-07-01

This paper describes the PLC based control system developed for a 40kJ/25kV Electro-magnetic machining (EMM) system. In EMM system large capacitor banks is charged with high voltage to store large energy and the banks is made to discharge into a coil within few milli-seconds using a triggered spark gaps. During discharge of the capacitor large surges and transients are generated in the system. The control system monitors/controls and interlocks all the units of the system for proper operation. The control system is the only subsystem which is electrically connected to all the low and high voltage subsystems. Care should be taken at the signal interfacing with the control system to protect the control system. (author)

A robust and stable PLC based control system for 40kJ/25kV EMM system

International Nuclear Information System (INIS)

Sharma, Vijay; Saroj, P.C.; Kulkarni, M.R.; Kumar, Satendra

2014-01-01

This paper describes the PLC based control system developed for a 40kJ/25kV Electro-magnetic machining (EMM) system. In EMM system large capacitor banks is charged with high voltage to store large energy and the banks is made to discharge into a coil within few milli-seconds using a triggered spark gaps. During discharge of the capacitor large surges and transients are generated in the system. The control system monitors/controls and interlocks all the units of the system for proper operation. The control system is the only subsystem which is electrically connected to all the low and high voltage subsystems. Care should be taken at the signal interfacing with the control system to protect the control system. (author)

Preliminary study on development of 300 Kv compact focused gaseous ion beam system

Energy Technology Data Exchange (ETDEWEB)

Ohkubo, T.; Ishii, Y.; Kamiya, T. [Takasaki Advanced Radiation Research Institute, Japan Atomic Energy Agency (JAEA) 1233 Watanuki-machi, Takasaki, Gunma, 370-1292 (Japan); Miyake, Y. [Beam Seiko Instruments Inc., 2-10-1 Kamata, Ohta-ku, Tokyo, 144-0052 (Japan)

2013-04-19

A new 300 kV compact focused gaseous ion beam (gas-FIB) system with three-stage acceleration lens was constructed at JAEA. The preliminary experiments of formation of the focused gaseous ion beams were carried out to show the availability of the gas-FIB system as a writing tool for 3D proton lithography. As a result of the experiments, it was proved that the focal point was kept at the same position under changing the kinetic energy but with keeping the kinetic energy ratio constant, which was defined as the ratio of kinetic energy in object side to that in image side for the third acceleration lens. This characteristic of the gas-FIB is a good point to advance the 3D proton lithography changing penetration depth in a sample by varying the beam energy.

Preliminary study on development of 300 Kv compact focused gaseous ion beam system

International Nuclear Information System (INIS)

Ohkubo, T.; Ishii, Y.; Kamiya, T.; Miyake, Y.

2013-01-01

A new 300 kV compact focused gaseous ion beam (gas-FIB) system with three-stage acceleration lens was constructed at JAEA. The preliminary experiments of formation of the focused gaseous ion beams were carried out to show the availability of the gas-FIB system as a writing tool for 3D proton lithography. As a result of the experiments, it was proved that the focal point was kept at the same position under changing the kinetic energy but with keeping the kinetic energy ratio constant, which was defined as the ratio of kinetic energy in object side to that in image side for the third acceleration lens. This characteristic of the gas-FIB is a good point to advance the 3D proton lithography changing penetration depth in a sample by varying the beam energy.

A 25 kWe low concentration methane catalytic combustion gas turbine prototype unit

International Nuclear Information System (INIS)

Su, Shi; Yu, Xinxiang

2015-01-01

Low concentration methane, emitted from various industries e.g. coal mines and landfills into atmosphere, is not only an important greenhouse gas, but also a wasted energy resource if not utilized. In the past decade, we have been developing a novel VAMCAT (ventilation air methane catalytic combustion gas turbine) technology. This turbine technology can be used to mitigate methane emissions for greenhouse gas reduction, and also to utilize the low concentration methane as an energy source. This paper presents our latest research results on the development and demonstration of a 25 kWe lean burn catalytic combustion gas turbine prototype unit. Recent experimental results show that the unit can be operated with 0.8 vol% of methane in air, producing about 19–21 kWe of electricity output. - Highlights: • A novel low concentration methane catalytic turbine prototype unit was developed. • The 25 kWe unit can be operated with ∼0.8 vol.% CH 4 in air with 19–21 kWe output. • A new start-up method was developed for the prototype unit

Turbulent diffusion of chemically reacting flows: Theory and numerical simulations.

Science.gov (United States)

Elperin, T; Kleeorin, N; Liberman, M; Lipatnikov, A N; Rogachevskii, I; Yu, R

2017-11-01

The theory of turbulent diffusion of chemically reacting gaseous admixtures developed previously [T. Elperin et al., Phys. Rev. E 90, 053001 (2014)PLEEE81539-375510.1103/PhysRevE.90.053001] is generalized for large yet finite Reynolds numbers and the dependence of turbulent diffusion coefficient on two parameters, the Reynolds number and Damköhler number (which characterizes a ratio of turbulent and reaction time scales), is obtained. Three-dimensional direct numerical simulations (DNSs) of a finite-thickness reaction wave for the first-order chemical reactions propagating in forced, homogeneous, isotropic, and incompressible turbulence are performed to validate the theoretically predicted effect of chemical reactions on turbulent diffusion. It is shown that the obtained DNS results are in good agreement with the developed theory.

Diffusion coefficient of hydrogen in niobium and tantalum

International Nuclear Information System (INIS)

Vargas, P.; Miranda, L.; Lagos, M.

1988-08-01

We show that the current data on hydrogen diffusion in Tantalum between 15K and 550K and in Niobium between 135K and 400K can be quantitatively explained by the small polaron theory. The experimental data can be understood assuming ground-state to ground-state tunneling between interstitial sites with tetrahedral symmetry plus an activated contribution due to tunneling between excited states having octahedral symmetry. The break of the diffusivity curve at T approx. = 250K follows naturally. It evidences the transition between the tetrahedral and octahedral hopping. For Ta the second break of the diffusivity curve at T approx. = 20K indicated the recovering of the ground-state hopping with tetrahedral symmetry. Below T approx. = 10K for Ta and T approx. = 7K for Nb the diffusion coefficient becomes independent of T. (author). 17 refs, 3 figs, 1 tab

Gaseous phase heat capacity of benzoic acid

NARCIS (Netherlands)

Santos, L.M.N.B.F.; Alves da Rocha, M.A.; Gomes, L.R.; Schröder, B.; Coutinho, J.A.P.

2010-01-01

The gaseous phase heat capacity of benzoic acid (BA) was proven using the experimental technique called the "in vacuum sublimation/vaporization Calvet microcalorimetry drop method". To overcome known experimental shortfalls, the gaseous phase heat capacity of BA monomer was estimated by ab initio

Chlorine diffusion in uranium dioxide under heavy ion irradiation

International Nuclear Information System (INIS)

Pipon, Y.; Bererd, N.; Moncoffre, N.; Peaucelle, C.; Toulhoat, N.; Jaffrezic, H.; Raimbault, L.; Sainsot, P.; Carlot, G.

2007-01-01

The radiation enhanced diffusion of chlorine in UO 2 during heavy ion irradiation is studied. In order to simulate the behaviour of 36 Cl, present as an impurity in UO 2 , 37 Cl has been implanted into the samples (projected range 200 nm). The samples were then irradiated with 63.5 MeV 127 I at two fluxes and two temperatures and the chlorine distribution was analyzed by SIMS. The results show that, during irradiation, the diffusion of the implanted chlorine is enhanced and slightly athermal with respect to pure thermal diffusion. A chlorine gain of 10% accumulating near the surface has been observed at 510 K. This corresponds to the displacement of pristine chlorine from a region of maximum defect concentration. This behaviour and the mean value of the apparent diffusion coefficient found for the implanted chlorine, around 2.5 x 10 -14 cm 2 s -1 , reflect the high mobility of chlorine in UO 2 during irradiation with fission products

Chlorine diffusion in uranium dioxide under heavy ion irradiation

Science.gov (United States)

Pipon, Y.; Bérerd, N.; Moncoffre, N.; Peaucelle, C.; Toulhoat, N.; Jaffrézic, H.; Raimbault, L.; Sainsot, P.; Carlot, G.

2007-04-01

The radiation enhanced diffusion of chlorine in UO2 during heavy ion irradiation is studied. In order to simulate the behaviour of 36Cl, present as an impurity in UO2, 37Cl has been implanted into the samples (projected range 200 nm). The samples were then irradiated with 63.5 MeV 127I at two fluxes and two temperatures and the chlorine distribution was analyzed by SIMS. The results show that, during irradiation, the diffusion of the implanted chlorine is enhanced and slightly athermal with respect to pure thermal diffusion. A chlorine gain of 10% accumulating near the surface has been observed at 510 K. This corresponds to the displacement of pristine chlorine from a region of maximum defect concentration. This behaviour and the mean value of the apparent diffusion coefficient found for the implanted chlorine, around 2.5 × 10-14 cm2 s-1, reflect the high mobility of chlorine in UO2 during irradiation with fission products.

Pollution prevention opportunity assessment for the K-25 Site Steam Plant -- Level 3

International Nuclear Information System (INIS)

1995-09-01

A Level 3 pollution prevention opportunity assessment (PPOA) was performed for the K-1501 Steam Plant at the K-25 Site. The primary objective was to identify and evaluate pollution prevention (P2) options to reduce the quantities of each waste stream generated by the Steam Plant. For each of the waste streams, P2 options were evaluated to first reduce the quantity of waste generated and second to recycle the waste. This report provides a process description of the facility; identification, evaluation, and recommendations of P2 options; an implementation schedule with funding sources; and conclusions. Largely for economic reasons, only 3 of the 14 P2 options are being recommended for implementation. All are source reduction options. When implemented, these three options are estimated to reduce the annual generation of waste by 658,412 kg and will result in a cost savings of approximately $29,232/year for the K-25 Site. The recommended options are to: install a flue gas return System in Boiler 7; reduce steam loss from traps; and increase lapse time between rinses. The four boilers currently in operation at the Steam Plant use natural gas or fuel oil as fuel sources

Experimental study of the aluminum droplet combustion under forced convection. Influence of the gaseous atmosphere; Etude experimentale de la combustion des gouttes d'aluminium en convection forcee. Influence de l'atmosphere gazeuse

Energy Technology Data Exchange (ETDEWEB)

Sarou-Kanian, V.

2003-12-15

Because of its high energetic power, the combustion of aluminum particles in solid propellant rocket motors improves the efficiency of heavy-lift launcher as Ariane 5. Aluminum particles burn in a gaseous atmosphere essentially composed of H{sub 2}O, CO{sub 2}, N{sub 2}, HCl, H{sub 2}, and CO, at high pressure (P=60-70 atm) and high temperature (T>3000 K). In the present work, we have been particularly interested in the influence of the gaseous atmosphere on the different burning processes both in the gas-phase and at the aluminum droplet surface. An experimental set-up was developed in order to describe precisely, thanks to several analysis techniques (high-speed camera, pyrometry, spectrometry, SEM, nuclear activation) the combustion of aerodynamically levitated millimetric aluminum droplets in gas mixtures with compositions close to the propellant ones (H{sub 2}O, CO{sub 2}, N{sub 2}). The main result is that each species plays a different role in the aluminum combustion. The water vapor has the biggest influence in the gas-phase process due to the production of hydrogen facilitating the heat and mass diffusion between the flame and the droplet. Nitrogen is essentially acting in surface reactions with the formation of aluminum nitride (AlN) and oxynitride (AlON) which may completely cover the droplet and stop the gas-phase combustion. Carbon dioxide has a double effect. On the one hand, CO{sub 2} burns in the flame, but it is less efficient than H{sub 2}O because the heat and mass transfer properties are poorer for CO than for H{sub 2}. On the other hand, a carbon dissolution phenomenon occurs in the aluminum droplet during burning which may reach saturation (20-25% molar) and involves a carbon rejection at the surface leading to the end of the gas-phase combustion. (author)

Laser-Excited Luminescent Tracers for Planar Concentration Measurements in Gaseous Jets

Science.gov (United States)

Lozano, Antonio

Tracers currently used in planar laser-induced fluorescence concentration measurements are not ideal for some experimental conditions, e.g., non-reacting turbulent gaseous flows at standard temperature and pressure. In this work, a number of chemicals have been evaluated, through consideration of their physical and photophysical properties, for use as luminescent concentration markers in turbulent gaseous flows. Two selected substances, biacetyl and acetone, have been studied in more detail. Acetone PLIF concentration images have been acquired in a non-reacting air jet, and the results have been compared to similar images obtained seeding with biacetyl. Acetone has proven to be a superior tracer when imaging fluorescence emission. Acetone has also been used as a fuel marker in hydrogen and methane diffusion flames. This single -laser technique enables simultaneous recording of the acetone and OH fluorescence emissions, as well as Mie scattering from ambient air dust particles. Acetone-sensitized, collisionally-induced biacetyl phosphorescence has been used to visualize molecular mixing in gaseous flows. Initial attempts to produce quantitative results with this method through simultaneous imaging of acetone fluorescence and collisionally-induced biacetyl emission, are described. Using laser-induced biacetyl phosphorescence imaging, a data set of cross-cut concentration images has been acquired in a nitrogen coflowing jet (Re = 5,000). The images have been statistically analyzed. Very simple models of the instantaneous concentration profile have been compared to the experimental data. Of all the tested models, a paraboloid has resulted to be the best approximation to the instantaneous 2-D profile. Finally, an experiment to study jet mixing in crossflow using acetone PLIF imaging has been designed. The flow facility has been constructed, and preliminary images obtained with a high quantum efficiency, thinned CCD detector have revealed the presence of jet structures

Effect of diluents on soot precursor formation and temperature in ethylene laminar diffusion flames

KAUST Repository

Abhinavam Kailasanathan, Ranjith Kumar

2013-03-01

Soot precursor species concentrations and flame temperature were measured in a diluted laminar co-flow jet diffusion flame at pressures up to eight atmospheres while varying diluent type. The objective of this study was to gain a better understanding of soot production and oxidation mechanisms, which could potentially lead to a reduction in soot emissions from practical combustion devices. Gaseous samples were extracted from the centerline of an ethylene-air laminar diffusion flame, which was diluted individually with four diluents (argon, helium, nitrogen, and carbon dioxide) to manipulate flame temperature and transport properties. The diluted fuel and co-flow exit velocities (top-hat profiles) were matched at all pressures to minimize shear-layer effects, and the mass fluxes were fixed over the pressure range to maintain constant Reynolds number. The flame temperature was measured using a fine gauge R-type thermocouple at pressures up to four atmospheres. Centerline concentration profiles of major non-fuel hydrocarbons collected via extractive sampling with a quartz microprobe and quantification using GC/MS+FID are reported within. The measured hydrocarbon species concentrations are vary dramatically with pressure and diluent, with the helium and carbon dioxide diluted flames yielding the largest and smallest concentrations of soot precursors, respectively. In the case of C2H2 and C6H6, two key soot precursors, helium diluted flames had concentrations more than three times higher compared with the carbon dioxide diluted flame. The peak flame temperature vary with diluents tested, as expected, with carbon dioxide diluted flame being the coolest, with a peak temperature of 1760K at 1atm, and the helium diluted flame being the hottest, with a peak temperature of 2140K. At four atmospheres, the helium diluted flame increased to 2240K, but the CO2 flame temperature increased more, decreasing the difference to approximately 250K. © 2012 The Combustion Institute.

Apparatus for studying the diffusion of rare gases in stainless steel; Appareil pour etude de la diffusion des gaz rares dans l'acier inoxydable

Energy Technology Data Exchange (ETDEWEB)

Stohr, J A; Alfille, L [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

1959-07-01

This apparatus enables measurements to be carried out on the diffusion of gaseous fission products and of gases in general across thin metallic walls at high temperatures. This work was initially intended to solve the problems involved in systems for detecting the rupture of a fuel element can (D.R.G.) by the diffusion of fission products through the cans at high temperatures. The extension of the work to other fields is envisaged. (author) [French] Cet appareil permet d'effectuer des mesures sur la diffusion des produits de fission gazeux, et des gaz en general, au travers de parois metalliques minces a haute temperature. Au depart, ce procede devait contribuer a resoudre les problemes poses aux systemes detecteurs de rupture de gaine (D.R.G.), par la diffusion des produits de fission au travers des gaines de cartouches a haute temperature. Son extension a d'autres etudes est envisagee. (auteur)

Natural gas diffusion model and diffusion computation in well Cai25 Bashan Group oil and gas reservoir

Institute of Scientific and Technical Information of China (English)

无

2001-01-01

Natural gas diffusion through the cap rock is mainly by means ofdissolving in water, so its concentration can be replaced by solubility, which varies with temperature, pressure and salinity in strata. Under certain geological conditions the maximal solubility is definite, so the diffusion com-putation can be handled approximately by stable state equation. Furthermore, on the basis of the restoration of the paleo-buried history, the diffusion is calculated with the dynamic method, and the result is very close to the real diffusion value in the geological history.

Gaseous distention of the hypopharynx and cervical esophagus with nasal CPAP: a mimicker of pharyngeal perforation and esophageal atresia

Energy Technology Data Exchange (ETDEWEB)

Walor, David; Berdon, Walter; Holt, Peter D.; Fox, Matthew [Columbia University Medical Center, Department of Radiology, New York, NY (United States); Children' s Hospital of New York, New York, NY (United States); Anderson, Nicole [Columbia University Medical Center, Department of Neonatology, New York, NY (United States); Children' s Hospital of New York, New York, NY (United States)

2005-12-01

Nasal continuous positive airway pressure (CPAP) has been used since 1975 as the initial treatment for respiratory distress syndrome (RDS) in very premature infants. Gaseous distention of the abdomen (CPAP belly) is a common secondary effect of CPAP. Gaseous distention of the hypopharynx is also common. To determine the incidence of hypopharyngeal distention in infants on CPAP. We performed a retrospective review of the chest radiographs of 57 premature infants treated with CPAP during a 4-week period to find the presence and degree of hypopharyngeal distention. Of the 57 radiographs, 14 (25%) revealed gaseous distention of the hypopharynx and/or cervical esophagus. On occasion, this raised concern for pharyngeal perforation or esophageal atresia. Awareness that CPAP-related hypopharyngeal distention is common should help radiologists avoid erroneous consideration of esophageal atresia or hypopharyngeal perforation. (orig.)

Gaseous distention of the hypopharynx and cervical esophagus with nasal CPAP: a mimicker of pharyngeal perforation and esophageal atresia

International Nuclear Information System (INIS)

Walor, David; Berdon, Walter; Holt, Peter D.; Fox, Matthew; Anderson, Nicole

2005-01-01

Nasal continuous positive airway pressure (CPAP) has been used since 1975 as the initial treatment for respiratory distress syndrome (RDS) in very premature infants. Gaseous distention of the abdomen (CPAP belly) is a common secondary effect of CPAP. Gaseous distention of the hypopharynx is also common. To determine the incidence of hypopharyngeal distention in infants on CPAP. We performed a retrospective review of the chest radiographs of 57 premature infants treated with CPAP during a 4-week period to find the presence and degree of hypopharyngeal distention. Of the 57 radiographs, 14 (25%) revealed gaseous distention of the hypopharynx and/or cervical esophagus. On occasion, this raised concern for pharyngeal perforation or esophageal atresia. Awareness that CPAP-related hypopharyngeal distention is common should help radiologists avoid erroneous consideration of esophageal atresia or hypopharyngeal perforation. (orig.)

Sterilization of allograft bone: is 25 kGy the gold standard for gamma irradiation?

Science.gov (United States)

Nguyen, Huynh; Morgan, David A F; Forwood, Mark R

2007-01-01

For several decades, a dose of 25 kGy of gamma irradiation has been recommended for terminal sterilization of medical products, including bone allografts. Practically, the application of a given gamma dose varies from tissue bank to tissue bank. While many banks use 25 kGy, some have adopted a higher dose, while some choose lower doses, and others do not use irradiation for terminal sterilization. A revolution in quality control in the tissue banking industry has occurred in line with development of quality assurance standards. These have resulted in significant reductions in the risk of contamination by microorganisms of final graft products. In light of these developments, there is sufficient rationale to re-establish a new standard dose, sufficient enough to sterilize allograft bone, while minimizing the adverse effects of gamma radiation on tissue properties. Using valid modifications, several authors have applied ISO standards to establish a radiation dose for bone allografts that is specific to systems employed in bone banking. These standards, and their verification, suggest that the actual dose could be significantly reduced from 25 kGy, while maintaining a valid sterility assurance level (SAL) of 10(-6). The current paper reviews the methods that have been used to develop radiation doses for terminal sterilization of medical products, and the current trend for selection of a specific dose for tissue banks.

Study of nitrogen solubility in multicomponent iron alloys at its pressure in gaseous phase up to 1000kPa

International Nuclear Information System (INIS)

Pomarin, Yu.M.; Grigorenko, G.M.; Latash, Yu.V.; Kanibolotskij, S.A.

1983-01-01

A facility in which metal is melted in a weighed state and nitrogen partical pressure during relting may be charge from 0 to 1000 kPa is developed to investigate nitrogen solubility is liquim metals and alloys. Investigation of nitrogen solubility was performed using samples of 03Kh25N5AM3 steel and Kh20N5, Kh20N10, Kh40N10, Kh40N20 alloys. Positive deflection of [N]=f(√Psub(Nsub(2))) dependence from the Henry law is shown to be observed in the Kh40N10 alloy in the 100-1000 kPa pressure range. In this case the vatue of positive deflection decreases with temperature growth and at T=2273 K nitrogen solubility in the alloy submits to the law of square root. An equation permitting to calculate nitrogen solubility in alloys of Fe-Cr-Ni and Fe-Cr-Mn systems in the 0 to 1000 kPa range of nitrogen partial pressures is obtained

The g-factor of the K=25 isomer in sup 182 Os

Energy Technology Data Exchange (ETDEWEB)

Alderson, A.; Fallon, P.; Goldring, G.; Roberts, J.; Sharpey-Schafer, J.; Twin P. (Liverpool Univ. (UK). Oliver Lodge Lab.); Bentley, M.; Bruce, A. (Science and Engineering Research Council, Daresbury (UK). Daresbury Lab.); Broude, C. (Weizmann Inst. of Science, Rehovoth (Israel). Dept. of Nuclear Physics); Dafni, E. (Rochester Univ., NY (USA). Nuclear Structure Research Lab.); Hass, M. (Argonne National Lab. (USA)); Nyberg, J.; Sletten, G. (Niels Bohr Inst., Roskilde (Denmark))

1989-09-28

The g-factor of the K=I=25 isomer in {sup 182}Os has been measured by observing the angular precession of the decay {gamma}-ray angular distribution in an external magnetic field as g=+0.425(8). This result is compared with predictions based on experimental g-factors of single-particle Nilsson orbitals in this mass region. (orig.).

Process for exchanging hydrogen isotopes between gaseous hydrogen and water

International Nuclear Information System (INIS)

Hindin, S. G.; Roberts, G. W.

1980-01-01

A process for exchanging isotopes of hydrogen, particularly tritium, between gaseous hydrogen and water is provided whereby gaseous hydrogen depeleted in tritium and liquid or gaseous water containing tritium are reacted in the presence of a metallic catalyst

Diffuse magmatic soil degassing at Soufriere of Guadeloupe, Antilles; Degazage magmatique diffus a la Soufriere de Guadeloupe, Antilles

Energy Technology Data Exchange (ETDEWEB)

Allard, P. [Centre National de la Recherche Scientifique (CNRS), 91 - Gif-sur-Yvette (France). Laboratoire des Sciences du Climat et de l`Environnement; Hammouya, G. [Observatoire Volcanologique de la Soufriere, IPGP, Le Houelmont, 97 - Gourbeyre, Guadeloupe (France); Parello, F. [Palermo Univ. (Italy). Dipt. di Chimica e Fisica della Terra ed Applicazioni

1998-09-01

A soil gas profiling made along the southern basis of Soufriere summit lave dome, in Guadeloupe, reveals the existence of diffuse emanations of magma-derived CO{sub 2} in coincidence with a major volcanic (Ty) fault, where CO{sub 2} concentrations at 70 cm depth in the ground reach 35-96 % and are associated with a thermal convective cell. Outside, a few `cold` gaseous anomalies of volcanic origin (lack of methane) provide reliable conditions for continuous radon monitoring of soil degassing. (authors) 14 refs.

Soil-gas diffusivity fingerprints of the dual porosity system in fractured limestone

DEFF Research Database (Denmark)

Claes, Niels; Chamindu, D.T.K.K.; Jensen, Jacob Birk

2010-01-01

processes are mostly limited to hydrogeological (water and solute) transport studies with very poor attention to the gaseous phase transport studies (Kristensen et al. 2010). This study characterizes fractured limestone soils for gas diffusion based on three different gas diffusivity fingerprints. The first...... fingerprint is a two-parameter exponential model, which mainly describes the gas diffusivity in the limestone matrix while taking both fracture connectivity and matrix pore connectivity into account. With the second fingerprint, we make a close observation of the tortuous matrix pore network by means...... of a modified Buckingham (1904) pore connectivity factor (X*). The third fingerprint of the fracture network involves the average angle of diffusion α (Moldrup et al. 2010), a parameter which characterizes the average angle at which the fractures are penetrating the sample....

Verification experiment on the downblending of high enriched uranium (HEU) at the Portsmouth Gaseous Diffusion Plant. Digital video surveillance of the HEU feed stations

International Nuclear Information System (INIS)

Martinez, R.L.; Tolk, K.; Whiting, N.; Castleberry, K.; Lenarduzzi, R.

1998-01-01

As part of a Safeguards Agreement between the US and the International Atomic Energy Agency (IAEA), the Portsmouth Gaseous Diffusion Plant, Piketon, Ohio, was added to the list of facilities eligible for the application of IAEA safeguards. Currently, the facility is in the process of downblending excess inventory of HEU to low enriched uranium (LEU) from US defense related programs for commercial use. An agreement was reached between the US and the IAEA that would allow the IAEA to conduct an independent verification experiment at the Portsmouth facility, resulting in the confirmation that the HEU was in fact downblended. The experiment provided an opportunity for the DOE laboratories to recommend solutions/measures for new IAEA safeguards applications. One of the measures recommended by Sandia National Laboratories (SNL), and selected by the IAEA, was a digital video surveillance system for monitoring activity at the HEU feed stations. This paper describes the SNL implementation of the digital video system and its integration with the Load Cell Based Weighing System (LCBWS) from Oak Ridge National Laboratory (ORNL). The implementation was based on commercially available technology that also satisfied IAEA criteria for tamper protection and data authentication. The core of the Portsmouth digital video surveillance system was based on two Digital Camera Modules (DMC-14) from Neumann Consultants, Germany

Simultaneous assessment of cerebral blood volume and diffusion heterogeneity using hybrid IVIM and DK MR imaging: initial experience with brain tumors

Energy Technology Data Exchange (ETDEWEB)

Wu, Wen-Chau [National Taiwan University, Graduate Institute of Oncology, Taipei (China); National Taiwan University, Graduate Institute of Clinical Medicine, Taipei (China); National Taiwan University, Graduate Institute of Biomedical Electronics and Bioinformatics, Taipei (China); National Taiwan University Hospital, Department of Medical Imaging, Taipei (China); Yang, Shun-Chung; Chen, Ya-Fang; My, Pei-Chi [National Taiwan University Hospital, Department of Medical Imaging, Taipei (China); Tseng, Han-Min [National Taiwan University Hospital, Department of Neurology, Taipei (China)

2017-01-15

To investigate the feasibility of simultaneously assessing cerebral blood volume and diffusion heterogeneity using hybrid diffusion-kurtosis (DK) and intravoxel-incoherent-motion (IVIM) MR imaging. Fifteen healthy volunteers and 30 patients with histologically proven brain tumours (25 WHO grade II-IV gliomas and five metastases) were recruited. On a 3-T system, diffusion-weighted imaging was performed with six b-values ranging from 0 to 1,700 s/mm{sup 2}. Nonlinear least-squares fitting was employed to extract diffusion coefficient (D), diffusion kurtosis coefficient (K, a measure of the degree of non-Gaussian and heterogeneous diffusion) and intravascular volume fraction (f, a measure proportional to cerebral blood volume). Repeated-measures multivariate analysis of variance and receiver operating characteristic analysis were performed to assess the ability of D/K/f in differentiating contrast-enhanced tumour from peritumoral oedema and normal-appearing white matter. Based on our imaging setting (baseline signal-to-noise ratio = 32-128), coefficient of variation was 14-20 % for K, ∝6 % for D and 26-44 % for f. The indexes were able to differentiate contrast-enhanced tumour (Wilks' λ = 0.026, p < 10{sup -3}), and performance was greatest with K, followed by f and D. Hybrid DK IVIM imaging is capable of simultaneously measuring cerebral perfusion and diffusion indexes that together may improve brain tumour diagnosis. (orig.)

Study of the reaction K-p→anti K0n at momenta of 25 and 40 GeV/c

International Nuclear Information System (INIS)

Apel, W.D.; Mueller, H.; Schneider, H.

1977-01-01

Measurements were made of the differential cross sections for the charge exchange of K - mesons on protons at momenta of 25 and 40 GeV/c using a high-precision spectrometer with no magnetic field. In the range 5-40 GeV/c the reaction cross section follows a power-law dependence psub(K - )sup(-1.52). In the small momentum transfer region (-t 2 sub(π) a minimum is observed, similar to that discovered at lower energies. The differential cross sections at t=0 are considerably less than those predicted by the Regge-pole model. The parameters of the effective trajectory are determined. (Auth.)

Office of Environmental Management Uranium Enrichment Decontamination and Decommissioning Fund financial statements, September 30, 1995 and 1994

Energy Technology Data Exchange (ETDEWEB)

NONE

1996-02-21

The Energy Policy Act of 1992 (Act) requires the Department of Energy to retain ownership and responsibility for the costs of environmental cleanup resulting from the Government`s operation of the three gaseous diffusion facilities located at the K-25 site in Oak Ridge, Tennessee; Paducah, Kentucky; and Portsmouth, Ohio. The Act transferred the uranium enrichment enterprise to the United States Enrichment Corporation (USEC) as of July 1, 1993, and established the Uranium Enrichment Decontamination and Decommissioning Fund (D&D Fund) to: Pay for the costs of decontamination and decommissioning at the diffusion facilities; pay the annual costs for remedial action at the diffusion facilities to the extent that the amount in the Fund is sufficient; and reimburse uranium/thorium licensees for the costs of decontamination, decommissioning, reclamation, and other remedial actions which are incident to sales to the Government.

Secondary processes in gaseous boron accompanying the cascade decay of the 1s-vacancy

International Nuclear Information System (INIS)

Bruehl, S.; Kochur, A.G.

2009-01-01

We employ the Monte-Carlo technique to simulate the processes in gaseous boron initiated by 1s-photoionization of boron atoms. The processes of excitations/ionizations of atoms by photons and electrons emitted by the neighboring decaying atoms are considered. It is found that the medium effect becomes noticeable at atomic densities of about 2.5·10 20 m -3 . (authors)

Operational experience of gaseous effluent treatment at the Eurochemic reprocessing plant

International Nuclear Information System (INIS)

Osipenco, A.; Detilleux, E.

1977-01-01

The EUROCHEMIC fuel reprocessing plant applies the PUREX flow sheet. Two particular features of the plant influence gaseous and liquid effluents: chemical decanning and the ability to process a wide range of fuels, uranium metal or oxide, having an initial enrichment typical of power reactors (up to 5%) or material testing reactors (up to 93%). The ventilation circuits, treatment plant and monitoring equipment for gaseous releases are briefly described. No retention facilities for rare gases, tritium, or carbon-14 are provided. The releases are monitored for krypton-85, iodine-131, alpha and beta-gamma aerosols and tritium. Between 1966 and 1974 the plant processes about 200 tonnes of power reactor fuel, from which about 0.7 tonnes of plutonium and 1.5 tonnes of highly enriched uranium were separated. The most important points in the operation of the gas cleaning equipment are indicated: efficiency, operational reliability, incidents, etc.. Actual discharges as measured are compared with the limits set in the operation licence. Using the atmospheric diffusion coefficients, the dose commitment is estimated. The low level liquid effluents are passed, after neutralization, to the treatment plant of the Belgian nuclear center CEN/SCK. However, if the activity exceeds the limit set by the CEN/SCK, the effluents are concentrated by evaporation and stored on the EUROCHEMIC site. (orig.) [de

Biomolecular solid state NMR with magic-angle spinning at 25K.

Science.gov (United States)

Thurber, Kent R; Tycko, Robert

2008-12-01

A magic-angle spinning (MAS) probe has been constructed which allows the sample to be cooled with helium, while the MAS bearing and drive gases are nitrogen. The sample can be cooled to 25K using roughly 3 L/h of liquid helium, while the 4-mm diameter rotor spins at 6.7 kHz with good stability (+/-5 Hz) for many hours. Proton decoupling fields up to at least 130 kHz can be applied. This helium-cooled MAS probe enables a variety of one-dimensional and two-dimensional NMR experiments on biomolecular solids and other materials at low temperatures, with signal-to-noise proportional to 1/T. We show examples of low-temperature (13)C NMR data for two biomolecular samples, namely the peptide Abeta(14-23) in the form of amyloid fibrils and the protein HP35 in frozen glycerol/water solution. Issues related to temperature calibration, spin-lattice relaxation at low temperatures, paramagnetic doping of frozen solutions, and (13)C MAS NMR linewidths are discussed.

Methods for reformation of gaseous hydrocarbons using electrical discharge

KAUST Repository

Cha, Min Suk

2017-02-16

Methods for the reformation of gaseous hydrocarbons are provided. The methods can include forming a bubble containing the gaseous hydrocarbon in a liquid. The bubble can be generated to pass in a gap between a pair of electrodes, whereby an electrical discharge is generated in the bubble at the gap between the electrodes. The electrodes can be a metal or metal alloy with a high melting point so they can sustain high voltages of up to about 200 kilovolts. The gaseous hydrocarbon can be combined with an additive gas such as molecular oxygen or carbon dioxide. The reformation of the gaseous hydrocarbon can produce mixtures containing one or more of H2, CO, H2O, CO2, and a lower hydrocarbon such as ethane or ethylene. The reformation of the gaseous hydrocarbon can produce low amounts of CO2 and H2O, e.g. about 15 mol-% or less.

Methods for reformation of gaseous hydrocarbons using electrical discharge

KAUST Repository

Cha, Min; Zhang, Xuming

2017-01-01

Methods for the reformation of gaseous hydrocarbons are provided. The methods can include forming a bubble containing the gaseous hydrocarbon in a liquid. The bubble can be generated to pass in a gap between a pair of electrodes, whereby an electrical discharge is generated in the bubble at the gap between the electrodes. The electrodes can be a metal or metal alloy with a high melting point so they can sustain high voltages of up to about 200 kilovolts. The gaseous hydrocarbon can be combined with an additive gas such as molecular oxygen or carbon dioxide. The reformation of the gaseous hydrocarbon can produce mixtures containing one or more of H2, CO, H2O, CO2, and a lower hydrocarbon such as ethane or ethylene. The reformation of the gaseous hydrocarbon can produce low amounts of CO2 and H2O, e.g. about 15 mol-% or less.

Development of on-line uranium enrichment monitor of gaseous UF6 for uranium enrichment plant

International Nuclear Information System (INIS)

Lu Xuesheng; Liu Guorong; Jin Huimin; Zhao Yonggang; Li Jinghuai; Hao Xueyuan; Ying Bin; Yu Zhaofei

2013-01-01

An on-line enrichment monitor was developed to measure the enrichment of UF 6 , flowing through the processing pipes in uranium enrichment plant. A Nal (Tl) detector was used to measure the count rates of the 185.7 keV γ-ray emitted from 235 U, and the total quantity of uranium was determined from thermodynamic characteristics of gaseous uranium hexafluoride. The results show that the maximum relative standard deviation is less than 1% when the measurement time is 120 s or more and the pressure is more than 2 kPa in the measurement chamber. Uranium enrichment of gaseous uranium hexafluoride in the output end of cascade can be monitored continuously by using the device. It should be effective for nuclear materials accountability verifications and materials balance verification at uranium enrichment plant. (authors)

France makes steady progress with lasers [enrichment

International Nuclear Information System (INIS)

Coates, J.-H.; Clerc, M.; Plurien, P.

1988-01-01

With the CHEMEX process now a commercially available technology, the French Commissariat a l'Energie (CEA) is focussing its R and D activity on two enrichment processes: gaseous diffusion, and atomic vapour laser isotope separation (AVLIS or SILVA). The SILVA process is being developed, with particular attention being paid to test campaigns undertaken on the pilot unit installed at Saclay. A core of technical know-how is being maintained in gaseous diffusion in order to study the behaviour of, and possible improvements to, the newly named George Besse plant at the Tricastin site. (U.K.)

Measurement of the temperature dependence of the ddμ-molecule formation rate in gaseous deuterium at the pressures 1.5 and 0.4 kbar

International Nuclear Information System (INIS)

Bystritskij, V.M.; Dzhelepov, V.P.; Zinov, V.G.

1990-01-01

In the experiment with a gaseous deuterium target of high pressure on the muon beam of the JINR phasotron the temperature dependence of the ddμ-molecule formation rate (λ ddμ ) has been measured. Measurements have been performed with liquid deuterium at the temperature T=20.3 K and with gaseous deuterium at pressure 1500 and 400 bar in the temperature region T=49-300 K. It is found that the value λ ddμ does not depend on the deuterium density for each temperature. The obtained results are in fairly good agreement with theory and with the data of other experiments made with deuterium of sufficiently (one-two order) lower density. 22 refs.; 3 figs.; 1 tab

Determination of diffusion coefficients of hydrogen in fused silica between 296 and 523 K by Raman spectroscopy and application of fused silica capillaries in studying redox reactions

Science.gov (United States)

Shang, L.; Chou, I-Ming; Lu, W.; Burruss, Robert; Zhang, Y.

2009-01-01

Diffusion coefficients (D) of hydrogen in fused silica capillaries (FSC) were determined between 296 and 523 K by Raman spectroscopy using CO2 as an internal standard. FSC capsules (3.25 × 10−4 m OD, 9.9 × 10−5 m ID, and ∼0.01 m long) containing CO2 and H2were prepared and the initial relative concentrations of hydrogen in these capsules were derived from the Raman peak-height ratios between H2 (near 587 cm−1) and CO2 (near 1387 cm−1). The sample capsules were then heated at a fixed temperature (T) at one atmosphere to let H2 diffuse out of the capsule, and the changes of hydrogen concentration were monitored by Raman spectroscopy after quench. This process was repeated using different heating durations at 296 (room T), 323, 375, 430, 473, and 523 K; the same sample capsule was used repeatedly at each temperature. The values of D (in m2 s−1) in FSC were obtained by fitting the observed changes of hydrogen concentration in the FSC capsule to an equation based on Fick’s law. Our D values are in good agreement with the more recent of the two previously reported experimental data sets, and both can be represented by:lnD=-(16.471±0.035)-44589±139RT(R2=0.99991)">lnD=-(16.471±0.035)-44589±139RT(R2=0.99991)where R is the gas constant (8.3145 J/mol K), T in Kelvin, and errors at 1σ level. The slope corresponds to an activation energy of 44.59 ± 0.14 kJ/mol.The D in FSC determined at 296 K is about an order of magnitude higher than that in platinum at 723 K, indicating that FSC is a suitable membrane for hydrogen at temperature between 673 K and room temperature, and has a great potential for studying redox reactions at these temperatures, especially for systems containing organic material and/or sulphur.

Electron beam irradiation of poly(perfluoro ethers): Identification of gaseous products as a result of main chain scission

International Nuclear Information System (INIS)

Pacansky, J.; Waltman, R.J.

1991-01-01

Several poly(perfluoro ethers) are exposed to electron beams to study the mechanism for main chain scission. Electron beam exposures were performed with the viscous poly(perfluoro ethers) under argon gas, and also at 9 K under vacuum, to determine mechanistic details for the chemical degradation. Here the authors report that, after main chain scission of the bulk poly(perfluoro ethers), sample weight loss is observed concomitant with evolution of gaseous products. Since this suggests that some unzipping of the polymer chain occurs, the products were identified and, most importantly, the efficiency for their formation was determined in terms of G values, and compared to known G values for main chain scission. The results show that COF 2 is the major gaseous product produced from unbranched ethers while CF 4 and COF 2 are the major products from branched polymers. The gaseous products were also exposed to the high-energy electron beam and the G values for decomposition are given