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Workshop on ENU Mutagenesis: Planning for Saturation, July 25-28, 2002 (open access)

Workshop on ENU Mutagenesis: Planning for Saturation, July 25-28, 2002

The goal of the conference is to enhance the development of improved technologies and new approaches to the identification of genes underlying chemically-induced mutant phenotypes. The conference brings together ENU mutagenesis experts from the United States and aborad for a small, intensive workshop to consider these issues.
Date: July 25, 2002
Creator: Nadeau, Joseph H
System: The UNT Digital Library
Local Integration of the National Atmospheric Release Advisory Center with Cities (LINC) (open access)

Local Integration of the National Atmospheric Release Advisory Center with Cities (LINC)

The objective of the ''Local Integration of the National Atmospheric Release Advisory Center with Cities'' (LINC) program is to demonstrate the capability for providing local government agencies with an advanced operational atmospheric plume prediction capability, which can be seamlessly integrated with appropriate federal agency support for homeland security applications. LINC is a Domestic Demonstration and Application Program (DDAP) funded by the Chemical and Biological National Security Program (CBNP), which is part of the Department of Energy's (DOE) National Nuclear Security Administration (NNSA). LINC will make use of capabilities that have been developed the CBNP, and integrated into the National Atmospheric Release Advisory Center (NARAC) at Lawrence Livermore National Laboratory (LLNL). NARAC tools services will be provided to pilot study cities and counties to map plumes from terrorism threats. Support to these local agencies will include training and customized support for exercises, special events, and general emergencies. NARAC provides tools and services that map the probable spread of hazardous material which have been accidentally or intentionally released into the atmosphere. Primarily supported by the DOE, NARAC is a national support and resource center for planning, real-time assessment and detailed studies of incidents involving a wide variety of hazards, including radiological, chemical, …
Date: March 25, 2002
Creator: Ermak, D L; Tull, J E & Mosley-Rovi, R
System: The UNT Digital Library
Temperature and Wavelength Dependent Emissivity of a Shocked Surface: A First Experiment (open access)

Temperature and Wavelength Dependent Emissivity of a Shocked Surface: A First Experiment

We have conducted an experiment in which the temperature and the wavelength dependent emissivity of a shocked surface has been measured. In the past, only the thermal emission from the shocked surface has been measured. The lack of knowledge of the emissivity as a function of wavelength leads to uncertainty in converting the measured emission spectrum into a surface temperature. We have developed a technique by which we are able to calculate both the emissivity of the shocked surface over a range of relevant wavelengths and the temperature of the surface. We use a multi-channel spectrometer in combination with a pulsed light source having a known spectrum of infrared radiation. Two separate techniques using a pulse of reflected radiation are employed and described. Both give the same result: An initially polished molybdenum surface that is shocked and partially released has a temperature of 1040 degrees Kelvin and a wavelength ({lambda}) dependent emissivity of 0.16 ({lambda}=1.2{micro}m), 0.10 ({lambda} =1.6 {micro}m), and 0.20 ({lambda} =2.3 {micro}m).
Date: January 25, 2002
Creator: Poulsen, P & Hare, D E
System: The UNT Digital Library
Strategies and tools for whole genome alignments (open access)

Strategies and tools for whole genome alignments

The availability of the assembled mouse genome makespossible, for the first time, an alignment and comparison of two largevertebrate genomes. We have investigated different strategies ofalignment for the subsequent analysis of conservation of genomes that areeffective for different quality assemblies. These strategies were appliedto the comparison of the working draft of the human genome with the MouseGenome Sequencing Consortium assembly, as well as other intermediatemouse assemblies. Our methods are fast and the resulting alignmentsexhibit a high degree of sensitivity, covering more than 90 percent ofknown coding exons in the human genome. We have obtained such coveragewhile preserving specificity. With a view towards the end user, we havedeveloped a suite of tools and websites for automatically aligning, andsubsequently browsing and working with whole genome comparisons. Wedescribe the use of these tools to identify conserved non-coding regionsbetween the human and mouse genomes, some of which have not beenidentified by other methods.
Date: November 25, 2002
Creator: Couronne, Olivier; Poliakov, Alexander; Bray, Nicolas; Ishkhanov,Tigran; Ryaboy, Dmitriy; Rubin, Edward et al.
System: The UNT Digital Library
Testing and modeling of seepage into underground openings in aheterogeneous fracture system at Yucca Mountain, Nevada (open access)

Testing and modeling of seepage into underground openings in aheterogeneous fracture system at Yucca Mountain, Nevada

We discuss field activities designed to characterize seepage into an underground opening at the potential site for geologic storage of high-level radioactive waste (HLRW) at Yucca Mountain, Nevada, and the use of these data for development and calibration of a model for predicting seepage into planned HLRW emplacement drifts. Air-injection tests were conducted to characterize the permeability of the fractured rock, and liquid-release tests (LRTs) were conducted and seepage monitored to characterize the seepage-relevant properties of the fractured rock. Both air-injection and liquid-release tests were performed in the same borehole intervals, located above the underground openings. For modeling, three-dimensional, heterogeneous permeability fields were generated, conditioned on the air-permeability data. The initial seepage data collected were used to calibrate the model and test the appropriateness of the modeling approach. A capillary-strength parameter and porosity were the model parameters selected for estimation by data inversion. However, due to the short-term nature of the initial data, the inversion process was unable to independently determine the capillary strength and porosity of the fractured rock. Subsequent seepage data collection focused on longer-term tests, a representative selection of which was used for data inversion. Field observations also played a key role by identifying factors such as …
Date: March 25, 2002
Creator: Ahlers, C. F.; Trautz, R. C.; Cook, P. J. & Finsterle, S.
System: The UNT Digital Library
Solidification Tests Conducted on Transuranic Mixed Oil Waste (TRUM) at the Rocky Flats Environmental Technology Site (RFETS) (open access)

Solidification Tests Conducted on Transuranic Mixed Oil Waste (TRUM) at the Rocky Flats Environmental Technology Site (RFETS)

Rocky Flats Environmental Technology Site (RFETS) near Golden, Colorado is the first major nuclear weapons site within the DOE complex that has been declared a full closure site. RFETS has been given the challenge of closing the site by 2006. Key to meeting this challenge is the removal of all waste from the site followed by site restoration. Crucial to meeting this challenge is Kaiser-Hill's (RFETS Operating Contractor) ability to dispose of significant quantities of ''orphan'' wastes. Orphan wastes are those with no current disposition for treatment or disposal. Once such waste stream, generically referred to as Transuranic oils, poses a significant threat to meeting the closure schedule. Historically, this waste stream, which consist of a variety of oil contaminated with a range of organic solvents were treated by simply mixing with Environstone. This treatment method rendered a solidified waste form, but unfortunately not a TRUPACT-II transportable waste. So for the last ten years, RFETS has been accumulating these TRU oils while searching for a non-controversial treatment option.
Date: February 25, 2002
Creator: Brunkow, W. G.; Campbell, D.; Geimer, R.; Gilbreath, C. & Rivera, M.
System: The UNT Digital Library
Optimized Conditioning of Activated Reactor Graphite (open access)

Optimized Conditioning of Activated Reactor Graphite

The research reactor DIORIT at the Paul Scherrer Institute was decommissioned in 1993 and is now being dismantled. One of the materials to be conditioned is activated reactor graphite, approximately 45 tons. A cost effective conditioning method has been developed. The graphite is crushed to less than 6 mm and added to concrete and grout. This graphite concrete is used as matrix for embedding dismantling waste in containers. The waste containers that would have been needed for separate conditioning and disposal of activated reactor graphite are thus saved. Applying the new method, the cost can be reduced from about 55 SFr/kg to about 17 SFr/kg graphite.
Date: February 25, 2002
Creator: Tress, G.; Doehring, L.; Pauli, H. & Beer, H.-F.
System: The UNT Digital Library
DECOMMISSIONING OF NUCLEAR FACILITIES IN GERMANY - STATUS AT BMBF SITES (open access)

DECOMMISSIONING OF NUCLEAR FACILITIES IN GERMANY - STATUS AT BMBF SITES

In a period of approximately 40 years prior to 1994, the German Federal Government had spent about {approx} 15 billion to promote nuclear technology. These funds were earmarked for R&D projects as well as demonstration facilities which took up operation between 1960 and 1980. These BMBF (Federal Ministry for Research) facilities were mainly located at the sites of the federal research centers at Juelich and Karlsruhe (the research reactors AVR, FR2, FRJ-1, KNK, and MZFR, the pilot reprocessing plant WAK) but included also the pilot plants SNR-300 and THTR-300 for fast breeder and high-temperature gas-cooled reactor development, respectively, and finally the salt mine Asse which had been used for waste emplacement prior to conversion into an underground research laboratory. In the meantime, almost all of these facilities were shut down and are now in a state of decommissioning and dismantling. This is mainly due to the facts that R&D needs are satisfied or do not exist any more and that, secondly, the lack of political consensus led to the cancellation of advanced nuclear technology.
Date: February 25, 2002
Creator: Papp, R. & Komorowski, K.
System: The UNT Digital Library
An Application of a State of the Art 3D-CAD-Modeling and Simulation System for the Decommissioning of Nuclear Capital Equipment in Respect of German Prototype Spent Fuel Reprocessing Plant Karlsruhe (open access)

An Application of a State of the Art 3D-CAD-Modeling and Simulation System for the Decommissioning of Nuclear Capital Equipment in Respect of German Prototype Spent Fuel Reprocessing Plant Karlsruhe

Siempelkamp Nukleartechnik GmbH is engaged in the optimization of decommissioning processes for several years. With respect of the complexity of the projects, the time frame and the budget it is necessary to find more effective ways to handle those tasks in the near future. The decommissioning and dismantling will be achieved in six steps taking into account that some processing equipment can be dismantled before and the rest only after the High Active Liquid Waste Concentrate (HAWC) has been vitrified approximately by mid of 2005. After the successful beginning of the remote dismantling of the main process cells from March 2000, the next remote dismantling project at the WAK was initiated April 2000.
Date: February 25, 2002
Creator: Schulz, M.; Boese, U. & Doering, K.
System: The UNT Digital Library
Immobilization of the Radionuclides from Spent Ion-Exchange Resins Using Vitrification (open access)

Immobilization of the Radionuclides from Spent Ion-Exchange Resins Using Vitrification

Approximately 60 g of an iron-enriched borosilicate glass was made in the radiochemical labs of the Savannah River Technology Center (SRTC). The glass was made to demonstrate the immobilization of the radioisotopes contained on representative Argentine ion exchange resins (similar to those used at the Embalse plant). The product was approximately 90% amorphous and was quite durable as measured by the release rates from the Product Consistency Test (PCT). The release rates were considerably better than those of the U. S. High Level Waste (HLW) benchmark DWPF EA glass. The release rate of the Cs-137 was predictably similar to that of Na and Li. No Co-60 or Sr-90 was measured in the PCT leachate. The mass balances for the inactive additives were quite good. Of the radioisotopes, approximately 71% of Cs-137 was accounted for in the glass product. This was similar to the Na mass balance. Approximately 89% of the Co-60 was accounted for in the glass product.
Date: February 25, 2002
Creator: Hutson, N. D.; Crawford, C. L.; Russo, D. O. & Sterba, M. E.
System: The UNT Digital Library
Synthetic and Virtual Environmental Media (SAVEM) (open access)

Synthetic and Virtual Environmental Media (SAVEM)

The Synthetic and Virtual Environmental Media (SAVEM) Program, developed at the DOE Environmental Measurements Laboratory, responds directly to issues of improved data quality, increased regulatory confidence, analytical laboratory waste minimization, pollution prevention, worker safety/radiation exposure risk reduction, and environmental stewardship. The SAVEM radiochemistry information analysis system uses digitally generated spectra to accurately model gamma-ray emission characteristics of radiological samples. A digital virtual sample can be specified that has the characteristics of any environmental media such as soil, sediment, or vegetation, and which exhibits the spectral characteristics of more than 2,000 gamma-emitting nuclides. The SAVEM system can duplicate the characteristics of 2,361 individual radionuclides with 47,902 gamma lines.
Date: February 25, 2002
Creator: Booth, F. H. K.; Decker, K. M.; Bath, R. J.; Bottrell, D. W. & Wright, K. L.
System: The UNT Digital Library
Surface Remediation in the Aleutian Islands: A Case Study of Amchitka Island, Alaska (open access)

Surface Remediation in the Aleutian Islands: A Case Study of Amchitka Island, Alaska

Amchitka Island, Alaska, was at one time an integral player in the nation's defense program. Located in the North Pacific Ocean in the Aleutian Island archipelago, the island was intermittently inhabited by several key government agencies, including the U.S. Army, the U.S. Atomic Energy Commission (predecessor agency to the U.S. Department of Energy), and the U.S. Navy. Since 1993, the U.S. Department of Energy (DOE) has conducted extensive investigations on Amchitka to determine the nature and extent of contamination resulting from historic nuclear testing. The uninhabited island was the site of three high-yield nuclear tests from 1965 to 1971. These test locations are now part of the DOE's National Nuclear Security Administration Nevada Operations Office's Environmental Management Program. In the summer of 2001, the DOE launched a large-scale remediation effort on Amchitka to perform agreed-upon corrective actions to the surface of the island. Due to the lack of resources available on Amchitka and logistical difficulties with conducting work at such a remote location, the DOE partnered with the Navy and U.S. Army Corps of Engineers (USACE) to share certain specified costs and resources. Attempting to negotiate the partnerships while organizing and implementing the surface remediation on Amchitka proved to be …
Date: February 25, 2002
Creator: Giblin, M. O.; Stahl, D. C. & Bechtel, J. A.
System: The UNT Digital Library
Conditioning of Degradated Packages with Radioactive Waste (open access)

Conditioning of Degradated Packages with Radioactive Waste

The development of the nuclear techniques in Romania and the commissioning of the WWR-S research reactor belonging to the Institute of Physics and Nuclear Engineering-(NIPNE) demand to deal with the storage and disposal of radioactive waste. The institute decided to store the radioactive waste inside a building that belonged to the Defense of Capital City System (the Army) called ''Fort'' which is located on the Magurele site. There are still about 800 packages containing cement conditioned radioactive in the storage facility of NIPNE which need to be repackaged, because they are in an advanced state of degradation. The new package obtained the regulatory design approval. It consists in an internal basket in which the degraded package are placed, a cement containment system, and an external cask in which the basket are placed and conditioned with the cement.
Date: February 25, 2002
Creator: Dogaru, G. C.
System: The UNT Digital Library
Application of Probabilistic Performance Assessment Modeling for Optimization of Maintenance Studies for Low-Level Radioactive Waste Disposal Sites at the Nevada Test Site (open access)

Application of Probabilistic Performance Assessment Modeling for Optimization of Maintenance Studies for Low-Level Radioactive Waste Disposal Sites at the Nevada Test Site

The U.S. Department of Energy (DOE), National Nuclear Security Administration of the Nevada Operations Office (NNSA/NV) operates and maintains two active facilities on the Nevada Test Site (NTS) that dispose defense-generated low-level radioactive waste (LLW), mixed radioactive waste, and ''classified waste'' in shallow trenches and pits. The operation and maintenance of the LLW disposal sites are self-regulated by the DOE under DOE Order 435.1. This Order requires formal review of a performance assessment (PA) and composite analysis (CA; assessment of all interacting radiological sources) for each LLW disposal system followed by an active maintenance program that extends through and beyond the site closure program. The Nevada disposal facilities continue to receive NTS-generated LLW and defense-generated LLW from across the DOE complex. The PA/CAs for the sites have been conditionally approved and the facilities are now under a formal maintenance program that requires testing of conceptual models, quantifying and attempting to reduce uncertainty, and implementing confirmatory and long-term background monitoring, all leading to eventual closure of the disposal sites. To streamline and reduce the cost of the maintenance program, the NNSA/NV is converting the deterministic PA/CAs to probabilistic models using GoldSim, a probabilistic simulation computer code. The output of probabilistic models …
Date: February 25, 2002
Creator: Crowe, B.; Yucel, V.; Rawlinson, S.; Black, P.; Carilli, J. & DiSanza, F.
System: The UNT Digital Library
Seminar in Critical Inquiry Twenty-first Century Nuclear Systems (open access)

Seminar in Critical Inquiry Twenty-first Century Nuclear Systems

Critical Inquiry, has not only been successful in increasing university student retention rate but also in improving student academic performance beyond the initial year of transition into the University. The seminar course herein reviewed is a balanced combination of student personal and academic skill development combined with a solid background in modern nuclear systems. It is a valid premise to assume that entering students as well as stakeholders of the general public demonstrate equal levels of capability. Nuclear systems is designed to give a broad and basic knowledge of nuclear power, medical, industrial, research, and military systems (nuclear systems) in 20-25 hours.
Date: February 25, 2002
Creator: LeMone, D. V.
System: The UNT Digital Library
Minimizing Characterization - Derived Waste at the Department of Energy Savannah River Site, Aiken, South Carolina (open access)

Minimizing Characterization - Derived Waste at the Department of Energy Savannah River Site, Aiken, South Carolina

Environmental restoration activities at the Department of Energy Savannah River Site (SRS) utilize innovative site characterization approaches and technologies that minimize waste generation. Characterization is typically conducted in phases, first by collecting large quantities of inexpensive data, followed by targeted minimally invasive drilling to collect depth-discrete soil/groundwater data, and concluded with the installation of permanent multi-level groundwater monitoring wells. Waste-reducing characterization methods utilize non-traditional drilling practices (sonic drilling), minimally intrusive (geoprobe, cone penetrometer) and non-intrusive (3-D seismic, ground penetration radar, aerial monitoring) investigative tools. Various types of sensor probes (moisture sensors, gamma spectroscopy, Raman spectroscopy, laser induced and X-ray fluorescence) and hydrophobic membranes (FLUTe) are used in conjunction with depth-discrete sampling techniques to obtain high-resolution 3-D plume profiles. Groundwater monitoring (short/long-term) approaches utilize multi-level sampling technologies (Strata-Sampler, Cone-Sipper, Solinst Waterloo, Westbay) and low-cost diffusion samplers for seepline/surface water sampling. Upon collection of soil and groundwater data, information is portrayed in a Geographic Information Systems (GIS) format for interpretation and planning purposes. At the SRS, the use of non-traditional drilling methods and minimally/non intrusive investigation approaches along with in-situ sampling methods has minimized waste generation and improved the effectiveness and efficiency of characterization activities.
Date: February 25, 2002
Creator: Van Pelt, R. S.; Amidon, M. B. & Reboul, S. H.
System: The UNT Digital Library
A system for combined three-dimensional morphological and molecular analysis of thick tissue specimens (open access)

A system for combined three-dimensional morphological and molecular analysis of thick tissue specimens

We present a new system for simultaneous morphological and molecular analysis of thick tissue samples. The system is composed of a computer assisted microscope and a JAVA-based image display, analysis and visualization program that allows acquisition, annotation, meaningful storage, three-dimensional reconstruction and analysis of structures of interest in thick sectioned tissue specimens. We describe the system in detail and illustrate its use by imaging, reconstructing and analyzing two complete tissue blocks which were differently processed and stained. One block was obtained from a ductal carcinoma in situ (DCIS) lumpectomy specimen and stained alternatively with Hematoxilyn and Eosin (H&E), and with a counterstain and fluorescence in situ hybridization (FISH) to the ERB-B2 gene. The second block contained a fully sectioned mammary gland of a mouse, stained for Histology with H&E. We show how the system greatly reduces the amount of interaction required for the acquisition and analysis and is therefore suitable for studies that require morphologically driven, wide scale (e.g., whole gland) analysis of complex tissue samples or cultures.
Date: April 25, 2002
Creator: Fernandez-Gonzalez, Rodrigo; Jones, Arthur; Garcia-Rodriguez, Enrique; Yuan Chen, Ping; Idica, Adam; Lockett, Stephen J. et al.
System: The UNT Digital Library
Comparison of Phases Formation Process in Initial and Mechanically Activated Ceramic Batches with Pyrochlore Formulations (open access)

Comparison of Phases Formation Process in Initial and Mechanically Activated Ceramic Batches with Pyrochlore Formulations

Formation of two pyrochlore ceramics with formulations CaZr0.25U0.75Ti2O7 and CaUTi2O7 within the temperature range 1000-1500 C from batches prepared by grinding of oxide powders in a mortar and an activator with hydrostatic yokes AGO-2U as well as soaking of a Ca, Zr, and Ti oxide mixture with uranylnitrate solution was studied. The pyrochlore ceramics are produced through intermediate calcium uranate formation. Phase formation reactions in the batch pre-treated in the AGO-2U unit were completed within the temperature range 1000-1100 C that is lower than in the batches prepared by two other methods.
Date: February 25, 2002
Creator: Stefanovsky, S. V.; Chizhevskaya, S. V. & Yudintsev, S. V.
System: The UNT Digital Library
Turning the Corner on Hanford Tank Waste Cleanup-From Safe Storage to Closure (open access)

Turning the Corner on Hanford Tank Waste Cleanup-From Safe Storage to Closure

The U.S. Department of Energy (DOE), Office of River Protection (ORP) is leading the River Protection Project (RPP) which is responsible for the disposition of 204,000 cubic meters (54 million gallons) of high-level radioactive waste that have accumulated in large underground tanks at the Hanford Site since 1944. ORP continues to make good progress on improving the capability to treat Hanford tank waste. Design of the waste vitrification facilities is proceeding well and construction will begin within the next year. Progress is also being made in reducing risk to the worker and the environment from the waste currently stored in the tank farms. Removal of liquids from single-shell tanks (SSTs) is on schedule and we will begin removing solids (salt cake) from a tank (241-U-107) in 2002. There is a sound technical foundation for the waste vitrification facilities. These initial facilities will be capable of treating (vitrifying) the bulk of Hanford tank waste and are the corners tone of the clean-up strategy. ORP recognizes that as the near-term work is performed, it is vital that there be an equally strong and defensible plan for completing the mission. ORP is proceeding on a three-pronged approach for moving the mission forward. First, …
Date: February 25, 2002
Creator: Boston, H. L.; Cruz, E. J. & Coleman, S. J.
System: The UNT Digital Library
Computerized Analytical Data Management System and Automated Analytical Sample Transfer System at the COGEMA Reprocessing Plants in La Hague (open access)

Computerized Analytical Data Management System and Automated Analytical Sample Transfer System at the COGEMA Reprocessing Plants in La Hague

Managing the operation of large commercial spent nuclear fuel reprocessing plants, such as UP3 and UP2-800 in La Hague, France, requires an extensive analytical program and the shortest possible analysis response times. COGEMA, together with its engineering subsidiary SGN, decided to build high-performance laboratories to support operations in its plants. These laboratories feature automated equipment, safe environments for operators, and short response times, all in centralized installations. Implementation of a computerized analytical data management system and a fully automated pneumatic system for the transfer of radioactive samples was a key factor contributing to the successful operation of the laboratories and plants.
Date: February 25, 2002
Creator: Flament, T.; Goasmat, F. & Poilane, F.
System: The UNT Digital Library
ABSORBING WIPP BRINES: A TRU WASTE DISPOSAL STRATEGY (open access)

ABSORBING WIPP BRINES: A TRU WASTE DISPOSAL STRATEGY

Los Alamos National Laboratory (LANL) has completed experiments involving 15 each, 250- liter experimental test containers of transuranic (TRU) heterogeneous waste immersed in two types of brine similar to those found in the underground portion of the Waste Isolation Pilot Plant (WIPP). To dispose of the waste without removing the brine from the test containers, LANL added commercially available cross-linked polyacrylate granules to absorb the 190 liters of brine in each container, making the waste compliant for shipping to the WIPP in a Standard Waste Box (SWB). Prior to performing the absorption, LANL and the manufacturer of the absorbent conducted laboratory and field tests to determine the ratio of absorbent to brine that would fully absorb the liquid. Bench scale tests indicated a ratio of 10 parts Castile brine to one part absorbent and 6.25 parts Brine A to one part absorbent. The minimum ratio of absorbent to brine was sought because headspace in the containers was limited. However, full scale testing revealed that the ratio should be adjusted to be about 15% richer in absorbent. Additional testing showed that the absorbent would not apply more than 13.8 kPa pressure on the walls of the vessel and that the absorbent …
Date: February 25, 2002
Creator: Yeamans, D. R. & Wrights, R. S.
System: The UNT Digital Library
SOLVENT EXTRACTION OF 99Tc FROM RADIOACTIVE INTERMEDIATE LIQUID WASTE BY DIBENZO-18-CROWN-6 (open access)

SOLVENT EXTRACTION OF 99Tc FROM RADIOACTIVE INTERMEDIATE LIQUID WASTE BY DIBENZO-18-CROWN-6

Technetium is one of the most prominent problems since its most stable specie in the environment, the pertechnetate ion, is highly mobile and considered as a long-term hazard in nuclear waste disposal. Because of the small activities of 99Tc relative to other fission products 137Cs or 90Sr, and its long half-life time (t1/2 = 2.1 x 105 yrs), 99Tc is one of the key isotopes that should always be analyzed in the radioactive liquid waste streams from the reprocessing industry where the largest concentrations are to be expected. Furthermore, as a pure beta-emitter, 99Tc has to be isolated from the intermediate level waste (ILW) stream prior to any measurement in such complex media. We have developed a method for 99Tc extraction providing recommendations that will be useful for extracting it from acid and basic ILW. The extraction of 99Tc from ILW by dibenzo-18-crown-6 (DB18C6) has been investigated and a simplex optimization of key parameters involved in the procedure has allowed us to set u p their best values. Experiments have been carried out on synthetic and real effluents from La Hague reprocessing plant, France, and results show that DB18C6 is highly selective towards 99Tc. The application of this procedure has …
Date: February 25, 2002
Creator: Paviet-Hartmann, P.
System: The UNT Digital Library
LaCl{sub 3}:Ce scintillator for Gamma ray detection (open access)

LaCl{sub 3}:Ce scintillator for Gamma ray detection

In this paper, we report on a relatively new cerium doped scintillator - LaCl3 for gamma ray spectroscopy. Crystals of this scintillator have been grown using Bridgman method. This material when doped with 10 percent cerium has high light output ({approx} 50,000 photons/MeV) and fast principal decay time constant ({approx}20 ns). Furthermore, it shows excellent energy resolution for gamma ray detection. For example, energy resolution as low as 3.2 percent (FWHM) has been achieved with 662 keV photons (137Cs source) at room temperature. Also high timing resolution (264 ps - FWHM) has been recorded with LaCl3-PMT and BaF2-PMT detectors operating in coincidence using 511 keV positron annihilation gamma ray pairs. Details of crystal growth, scintillation properties, and variation of these properties with cerium concentration are also reported.
Date: May 25, 2002
Creator: Shah, K. S.; Glodo, J.; Klugerman, M.; Cirignano, L.; Moses, W. W.; Derenzo, S. E. et al.
System: The UNT Digital Library
Enhancing Effectiveness of EMSP Projects Through Strong Connections to Site Problems (open access)

Enhancing Effectiveness of EMSP Projects Through Strong Connections to Site Problems

The Environmental Management Science Program (EMSP) funds basic science research that will lead to reduced remediation cost, schedule, technical uncertainties, and risk for DOE's environmental clean up. The Tanks Focus Area (TFA) has partnered with EMSP to accomplish those same objectives for DOE's largest and most expensive remediation effort--to retrieve and immobilize the highly radioactive wastes that are our nation's chief nuclear defense program legacy. TFA has been tasked to facilitate success of the EMSP investment. The key for EMSP projects to contribute to this remediation effort is communication. First, scientists need to understand much more about how their scientific results would be used than they could ever learn from the original EMSP solicitation or by reading the referenced DOE needs statements. Second, the scientists' results must be communicated to the site problem holders in a usable form and in a timely manner such that important information gaps can still be filled by the EMSP project. Research results can be used in a variety of ways besides deployment of new hardware or a new process. When results are USED the site problem holders become ''users''. The important aspect that research results are to be used is captured in the TFA …
Date: February 25, 2002
Creator: Guillen, D. P. & Josephson, G. B.
System: The UNT Digital Library