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Validation of the atmospheric transport model: comparison of observed krypton-85 concentrations with those computed using a Gaussian plume model

Description: Thirty monthly average /sup 85/Kr concentrations measured at 13 sampling locations between 25 and 150 km from a quasi-continuous point source were used in a validation study of the Atmospheric Transport Model for Toxic Substances (ATM-TOX). Although the computed values tended to overestimate, more than 60% of them fell within a factor of 2 of the observed concentrations.
Date: January 1, 1982
Creator: Raridon, R.J. & Murphy, B.D.
Partner: UNT Libraries Government Documents Department

Iodine-123 generator/iodination kit: a preliminary report

Description: Preliminary results are described of a xenon-123 filled device to serve as a combination iodine-123 generator/iodination kit. Xenon-123 is produced in the Brookhaven Linac Isotope Producer (BLIP) by the reaction /sup 127/I(p, 5n)/sup 123/Xe. The device consists of a small glass ampoule containing an internal glass breakseal and a flanged neck on which is crimped a multi-injection type septum. The ampoule contains a hydrogen sulfide atmosphere to assure that the iodine generated from the decay of the xenon is in the form of iodide. Following an adequate period for xenon-123 to decay (this period can be used for shipment), a needle is forced through the septum breaking the seal and residual gases are pumped off. The iodine-123 in the form of iodide can then be rinsed from the ampoule with any desired solvent or reagent added directly to the device to carry out an iodination in an enclosed environment. Preliminary results of both iodine recovery and iodinations have been promising.
Date: January 1, 1980
Creator: Richards, P; Prach, T; Srivastava, S C & Meinken, G E
Partner: UNT Libraries Government Documents Department

/sup 18/F-4-fluoroantipyrine

Description: The novel radioactive compound /sup 18/F-4-fluoroantipyrine having high specific activity which can be used in nuclear medicine in diagnostic applications, prepared by the direct fluorination of antipyrine in acetic acid with radioactive fluorine at room temperature and purifying said radioactive compound by means of gel chromatography with ethyl acetate as eluent is disclosed. The non-radioactive 4-fluoroantipyrine can also be prepared by the direct fluorination of antipyrine in acetic acid with molecular fluorine at room temperature and purified by means of gel chromatography with ethyl acetate eluent.
Date: January 1, 1980
Creator: Shiue, C.Y. & Wolf, A.P.
Partner: UNT Libraries Government Documents Department

Design of a /sup 18/F production system at ORNL 86-inch cyclotron

Description: A target system for the production of /sup 18/F by proton bombardment of H/sub 2//sup 18/O was designed for the ORNL 86-inch cyclotron facility. The system consists of concentric titanium and aluminum cylinders. Oxygen-18-enriched H/sub 2/O circulates through the inner titanium cylinder and through an external heat exchanger with cooling water flowing in the annulus. Yields of 5.0 curies are expected for a 250-..mu..A proton beam current and 24-min irradiation time.
Date: October 19, 1977
Creator: Shaeffer, M.C.; Barreto, F.; Datesh, J.R. & Goldstein, B.R.
Partner: UNT Libraries Government Documents Department

Very elongated nuclei near A = 194

Description: A {gamma}-ray cascade in {sup 191}Hg of 12 members with average energy spacing 37 keV and Q{sub t} {equals} 18(3)eb was reported by Moore, and coworkers in 1989. This was the first report of very elongated nuclei (superdeformation) in this mass region. Since then, some 25 {gamma}-ray cascades have been observed in 11 (slightly neutron deficient) Hg, Pb and Tl nuclei. The bands have similar dynamic moments-of-inertia. Some nuclei exhibit multiple bands, and the backbending phenomena has been observed. Level spins can be obtained from comparison of transition energies to rotational model formulas. Selected bands (in different nuclei) have equal transition energies (within 0.1%). Alignment in integer multiples of {h bar} has been observed. Properties of these bands will be described. 27 refs., 3 figs.
Date: October 1, 1990
Creator: Becker, J.A.; Henry, E.A.; Yates, S.W.; Wang, T.F.; Kuhnert, A. (Lawrence Livermore National Lab., CA (USA)); Brinkman, M.J. et al.
Partner: UNT Libraries Government Documents Department

Development of chemical isolation and concentration techniques for Tc-99 analysis by resin-bead mass spectrometry

Description: A novel, highly sensitive, isotope-dilution analytical technique for the determination of technetium-99 has been developed around single ion-exchange bead mass spectrometry. Mass spectrometry is much more sensitive than direct counting for the low-energy, low-specific activity, Tc-99 isotope. Further, the point source provided by a single ion-exchange bead leads to a greater signal-to-noise ratio in the mass spectrometric measurement than does conventional application of a solution to the source filament. Recent results indicate a sensitivity greater than 0.1 picogram. Isolation of technetium from the samples occurs after addition of Tc-97 as a yield tracer. A combination of ion-exchange chromatography and ion-association solvent extraction provides decontamination from the potential interferences, Mo-97 and Ru-99. Subsequently, the technetium is loaded onto a pair of anion-exchange beads (diameter approx. 0.3 mm). The noncritical isolation and bead-loading scheme typically concentrates the technetium in the sample by a factor of about a million with overall recoveries exceeding 50%. A variety of environmental samples from the Savannah River Plant (SRP) has been analyzed by this method.
Date: January 1, 1979
Creator: Anderson, T.J.
Partner: UNT Libraries Government Documents Department

Kinetics of stimulated Moessbauer emission in neutron-pumped krypton-83

Description: Using an idealized kinetic model for a gamma-ray laser system pumped by a spatially uniform delta-function burst of fast neutrons, a computer study has been made of the growth, decay, and attenuation of resonant 9.3-keV recoil-less gamma radiation from /sup 83/Kr, as a function of neutron-burst intensity, gamma-ray linebreadth, temperature, dilution of krypton in a beryllium host, and nonresonant absorption coefficient of the host. The isomer is formed by neutron capture in a 40-eV resonance, and the 144-ns transition lifetime is short in comparison with the time for neutrons to moderate. The kinetic behavior of this system is therefore determined largely by the time dependence of the neutron spectrum and only slightly by the reciprocal linebreadth of the graser transition. Because the lower state is stable, inversion is rapidly lost, so that, for observable gain, an unrealistically high source intensity is needed. Use of a beryllium host, which increases the Debye temperature, is negated by its parasitic absorption. Although this transition is unsuitable for a graser, these findings help to illustrate useful properties of nuclear isomers and solid hosts for which stimulated emission might be observable.
Date: November 1, 1977
Creator: Baldwin, G.C. & McNeil, L.E.
Partner: UNT Libraries Government Documents Department

/sup 123/I research and production at Brookhaven

Description: The procedures for preparing high purity /sup 123/I at the BLIP using the /sup 127/I(p,5n)/sup 123/Xe reaction on an NaI target are described. The activity is supplied in a glass ampoule with anhydrous /sup 123/I deposited on the interior walls, allowing maximum flexibility in subsequent iodinations. Preliminary experience with a continuous flow target is also described. The results of a series of measurements of specific activity by neutron activation, x-ray fluorescence, uv absorption, and wet chemistry generally showed no detectable carrier. HPLC methods to analyse the chemical form of radioiodine and to characterize various iodinated radiopharmaceuticals have been developed. These methods provide higher sensitivity, speed and resolution than commonly used techniques. 19 refs., 6 figs., 2 tabs.
Date: January 1, 1985
Creator: Mausner, L.F.; Srivastava, S.C.; Mirzadeh, S.; Meinken, G.E. & Prach, T.
Partner: UNT Libraries Government Documents Department

Strategy analysis for krypton-85 waste management

Description: Krypton-85 is a chemically inert, radioactive gas produced by fission of uranium or plutonium isotopes. Depending on the fuel cycle, krypton-85 production in nuclear reactors may range from approx. 200 to approx. 600 kCi/GW/sub e/-year. However, the EPA has published a standard restricting krypton-85 release to 50 kCi/GW/sub e/-year for fuel irradiated after January 1, 1983. To conform with the federal standard, recovery and storage of krypton-85 will be required in some nuclear fuel cycle processes. The long-term waste management of krypton-85 poses unique judgemental problems. Release, recovery, immobilization, and storage (individually, and in combinations), involve a wide range of environmental, economic, and social commitments. The choice of applicable technologies, if such technologies are to be used at all, imposes another set of boundary conditions. This strategy analysis describes the use of a general framework for decision-making in evaluating krypton-85 waste management systems. Such a framework can be further used to provide technical assessment and dose-probability calculations for individual technologies, and to show the interactions among technological options required for the overall waste management scheme.
Date: January 1, 1979
Creator: Knecht, D.A. & Brown, R.A.
Partner: UNT Libraries Government Documents Department

/sup 189/Os and the U(6/12) symmetry scheme

Description: This contribution will consider the extension of the U(6/12) symmetry scheme to the region intermediate between the 0(6) and SU(3) limits and will compare the predicted level structure with that determined empirically for /sup 189/Os.
Date: January 1, 1986
Creator: Bruce, A.M.; Warner, D.D.; Campbell, M.J. & Gelletly, W.
Partner: UNT Libraries Government Documents Department

Near source tracers at Hanford. [Krypton-85]

Description: Atmospheric tracer techniques are reviewed, with emphasis on the Hanford inert gas krypton-85 field technique. This technique is considerably more sophisticated than the visible and particulate tracer techniques. The krypton technique develops histories of concentration at up to 128 field locations; the particulate techniques generate only bulk time integrated samples. The krypton dispersal technique permits release of either a plume or a true puff; the particulate techniques permit continuous releases, but only approximations of puffs through short continuous releases. The Hanford krypton-85 inert gas system offers the advantages of an inert gas tracer, permits release of either puffs or plumes, and presents histories of concentration as opposed to only time-integrated concentrations. However, the approach used has the disadvantages of being usable at only short distances, is a relatively expensive system to deploy and maintain, and is restricted as to locations where it may be used due to the radioactive nature of the tracer.
Date: May 1, 1979
Creator: Nickola, P. W.
Partner: UNT Libraries Government Documents Department

Mapping of functional activity in brain with /sup 18/F-fluoro-deoxyglucose

Description: A model has been designed based on the assumptions of a steady state for glucose consumption, a first-order equilibration of the free /sup 14/C-DG pool in the tissue with the plasma level, and relative rates of phosphorylation of /sup 14/C-DG and glucose determined by their kinetic constants for hexokinase reaction. Using an operational equation based on this model, the metabolic rates of glucose are calculated in various regions of brain (utilizing brain slices and autoradiography). /sup 14/C is a beta emitter and therefore not suitable for noninvasive imaging in man. With the synthesis of /sup 18/F-2-deoxy-2-fluoro-D-glucose (/sup 18/F-DG) all of the requirements for a suitable radiopharmaceutical for the determination of local cerebral metabolism have been met. This agent behaves very similarly to /sup 14/C-DG and therefore, using the above described model and emission tomography, it has become possible to measure regional cerebral metabolism for the first time in man.
Date: January 1, 1981
Creator: Alavi, A.; Reivich, M.; Greenberg, J. & Wolf, A.
Partner: UNT Libraries Government Documents Department

Uptake and distribution of technetium in several marine algae

Description: The uptake or chemical form of technetium in different marine algae (Acetabularia, Cystoseira, Fucus) has been examined and a simple model to explain the uptake of technetium in the unicellular alga, Acetabularia, has been conceptualized. At low concentrations in the external medium, Acetabularia can rapidly concentrate technetium. Concentration factors in excess of 400 can be attained after a time of about 3 weeks. At higher mass concentrations in the medium, uptake of technetium by Acetabularia becomes saturated resulting in a decreased concentration factor (approximately 10 after 4 weeks). Approximately 69% of the total radioactivity present in /sup 95m/Tc labelled Acetabularia is found in the cell cytosol. In Fucus vesiculosus, labelled with /sup 95m/Tc, a high percentage of technetium is present in soluble ionic forms while approximately 40% is bound, in this brown alga, in proteins and polysaccharides associated with cell walls. In the algal cytosol of Fucus vesiculosus, about 45% of the /sup 95m/Tc appears to be present as anionic TcO/sup -//sub 4/ and the remainder is bound to small molecules. 8 references, 5 figures, 1 table.
Date: January 1, 1983
Creator: Bonotto, S.; Gerber, G.B.; Garten, C.T. Jr.; Vandecasteele, C.M.; Myttenaere, C.; Van Baelen, J. et al.
Partner: UNT Libraries Government Documents Department

Modeling and interpretation of two-phase flow and tracer studies from a subbituminous coal seam in the San Juan basin of New Mexico

Description: Field and modeling studies were performed to characterize two-phase flow within the natural cleat structure of an upper Cretaceous subbituminous coal seam. A two borehole pattern with open completion was used in a study of dewatering and tracer residence time distribution. Air was pumped into a five meter thick seam located about 170 meters below the surface. Krypton 85 was used as the airborne tracer. Air inflow and air and water production rates and tracer arrival times were monitored. The field tests were simulated with a two-phase, three component, porous flow code. Results showed that the air inflow and air and water outflow rates and breakthrough times could not be modeled assuming a uniform darcy-type permeability. The use of a pressure dependent permeability did provide, however, a much better match with the field data.
Date: January 1, 1980
Creator: Nuttall, H.E. & Travis, B.J.
Partner: UNT Libraries Government Documents Department

Safety and environmental aspects of HYLIFE-II

Description: The HYLIFE-II inertial confinement fusion reactor uses a Flibe spray for blast chamber protection and tritium breeding. HYLIFE-II is passively safe, having no large sources of energy available to disperse radioactive materials. The dominant activation product is {sup 18}F (half-life 110 minutes). Only a small fraction (< 10{sup {minus}5}) of the Flibe activation products would be mobilized. The offsite dose from a severe accident involving simultaneous failure of the blast chamber and containment building would be < 0.2 mSv (20 mrem), and N-stamp requirements could be avoided in the blast chamber and coolant systems. The required tritium removal efficiencies are quantified. 10 refs., 1 fig.
Date: January 1, 1990
Creator: Dolan, T.J. & Longhurst, G.R. (Idaho National Engineering Lab., Idaho Falls, ID (USA))
Partner: UNT Libraries Government Documents Department

Experimental and statistical investigation of thermally induced failure in reactor fuel particles

Description: An incomplete experimental study into the failure statistics of fuel particle for the high-temperature gas-cooled reactor (HTGR) is described. Fuel particles failure was induced by thermal ramping from room temperature to temperatures in the vicinity of 2273/sup 0/K to 2773/sup 0/K in 2 to 30 h and detected by the appearance of /sup 85/Kr in the helium carrier gas used to sweep the furnace. The concentration of krypton, a beta emitter, was detected by measuring the current that resulted when the helium sweep gas was passed through an ionization chamber. TRISO fuel particles gave a krypton concentration profile as a function of time that built up in several minutes and decayed in a fraction of an hour. This profile, which was temperature independent, was similar to the impulse response of the ionization chamber, suggesting that the TRISO particles failed instantaneously and completely. BISO fuel particles gave a krypton concentration profile as a function of time that built up in a fraction of an hour and decayed in a fraction of a day. This profile was strongly temperature dependent, suggesting that krypton release was diffusion controlled, i.e., that the krypton was diffusing through a sound coat, or that the BISO coating failed but that the krypton was unable to escape the kernel without diffusion, or that a combination of pre- and postfailure diffusion accompanied partial or complete failure.
Date: October 1, 1980
Creator: Lunsford, J.L.; Imprescia, R.J.; Bowman, A.L. & Radosevich, C.E.
Partner: UNT Libraries Government Documents Department

Lifetime measurement of the correlated continuum gamma rays in /sup 170/Hf

Description: Continuum gamma rays are generally emitted at the early stages of the gamma decay of a compound nucleus. These gamma rays are from states with higher angular momentum and excitation energy than the discrete gamma rays. Therefore, from the study of continuum gamma rays it is possible to obtain information on nuclear properties in regions unreachable through studies of discrete transitions. In the current measurements we have applied the Doppler-Shift Attenuation Method to the full gamma-gamma correlation matrix, enabling us to determine the lifetime of the ridge in /sup 170/Hf over a large range of energy. With our Compton Suppression Spectrometer System, it was possible to carry out these measurements with good energy resolution and a high peak-to-Compton ratio. 2 refs., 2 figs.
Date: January 1, 1988
Creator: Lee, I.Y.
Partner: UNT Libraries Government Documents Department

Ion implantation of krypton in sputter-deposited metal matrices

Description: Krypton 85 has been successfully stored in a metal matrix by bombarding the metal surface with krypton ions while the metal is being deposited by sputtering. The krypton is thus incorporated into the metal in concentrations approaching 200 cm/sup 3/ of Kr(STP)cm/sup 3/ of deposit. Cost estimates of a facility to perform this work are given. (GHT)
Date: June 1, 1980
Creator: Tingey, G.L.; McClanahan, E.D. & Nesbitt, J.F.
Partner: UNT Libraries Government Documents Department

Reaction studies of hot silicon and germanium radicals. Progress report, September 1, 1981-September 30, 1982

Description: Progress in two areas important to attaining the goals of this research program are briefly reviewed: (a) characterization of the major product-forming intermediate in the reactions of recoiling silicon atoms; (b) time-resolved laser flash spectroscopic studies of the generation and reactions of silicon radicals. 1 figure.
Date: September 30, 1982
Creator: Gaspar, P. P.
Partner: UNT Libraries Government Documents Department

High sensitivity technetium analysis using negative thermal ionization mass spectrometry

Description: Determination of the reaction products of solar neutrinos with /sup 98/Mo and /sup 97/Mo to produce /approximately/10/sup 8/ atoms of /sup 98/Tc and /sup 97/Tc in 10/sup 4/ tons of ore for the last several million years have prompted the development of highly sensitive isotopic analytical technique for technetium. Secular equilibrium /sup 99/Tc, present in the ore at 10/sup 8/ to 10/sup 9/ atom levels will be used for an internal tracer to fix absolute atom amounts. Previous work has suggested that negative thermal ionization can produce high ionization efficiency for certain selected elements, including technetium. Negative thermal ionization has several advantages over the positive ion approach. Technetium forms the pertechnetate ion while the most common and abundant isobaric impurity, molybdenum, forms MoO/sub 3//sup /minus//. In addition, technetium forms negative ions very efficiently; efficiencies of >2% have been measured. Positive ion techniques are much less efficient. Organic impurities also are much less troublesome in the negative ionization mode. 6 refs.
Date: January 1, 1988
Creator: Rokop, D.J.; Schroeder, N.C. & Wolfsberg, K.
Partner: UNT Libraries Government Documents Department

Alumina column Rb-82 generator

Description: The use of an alumina column for the adsorption of radioactive Sr for the generator production of 75-sec /sup 82/Rb was evaluated in both batches and column experiments using /sup 85/Sr and cyclotron-produced /sup 82/Sr. Comparisons of alumina, Bio-Rex 70 and Chelex 100 ion exchangers were made to determine Sr adsorption, /sup 82/Rb elution yield and Sr breakthrough. The adsorption of Sr is similar for alumina and Chelex 100 but different for Bio-Rex 70. Alumina and Chelex 100 exhibit a small fraction of poorly bound Sr which appears as higher breakthrough in the early elution volumes. The remaining Sr activity is strongly bound to these ion exchangers and the breakthrough remains stable at a lower breakthrough value through a large number of elutions. Bio-Rex 70 on the other hand does not exhibit the poorly bound Sr fraction and the breakthrough of Sr remains the lowest of the three ion exchangers through a moderate number of elutions and then the Sr breakthrough gradually increases with each additional elution.
Date: October 1, 1977
Creator: Yano, Y. & Roth, E.P.
Partner: UNT Libraries Government Documents Department

Entrapment of krypton in sputter deposited metals: a storage medium for radioactive gases

Description: Sputter deposition of metals with a negative substrate bias results in a deposit containing relatively large concentrations of the sputtering gas. This phenomenon has been applied as a technique for storage of the radioactive gas, /sup 85/Kr, which is generated in nuclear fuels for power production. Alloys which sputter to yield an amorphous product have been shown to contain up to 12 atom % Kr (42 cm/sup 3/ of Kr(STP)/g of deposit; concentration equivalent to a gas at 4380 psi pressure). Release from these metals occurs at so low a rate that extrapolation to long times yields a /sup 85/Kr release at 300/sup 0/C of about 0.06% in 100 years. A preliminary evaluation of the engineering feasibility and economics of the sputtering process indicates that /sup 85/Kr can be effectively trapped in a solid matrix with currently available techniques on a scale required for handling DOE-generated waste or commercial reprocessed fuels and that the cost should not be a limiting factor.
Date: April 1, 1979
Creator: Tingey, G.L.; McClanahan, E.D.; Bayne, M.A. & Moss, R.W.
Partner: UNT Libraries Government Documents Department