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Determination of Parts-Per-Million Cesium in Simulated Nuclear Waste with the Cesium-Selective Electrode

Description: Because the molybdophosphate electrode was not sufficiently sensitive, and the reliability of the ''liquid state'' electrode for routine analysis was uncertain, a cesium-selective electrode of the proven liquid membrane type was developed. This paper describes preparation and testing of a liquid membrane electrode that contains cesium tetraphenylboron dissolved in 4-ethylnitrobenzene.
Date: October 23, 2001
Creator: Baumann, E. W.
Partner: UNT Libraries Government Documents Department

Determination of Free Acid by Standard Addition with Potassium Thiocyanate as Complexant

Description: A method is described for determination of free acid in solutions containing the hydrolyzable ions Al (III), Cr(III), Fe(III), Hg(II), Ni(II), Th(IV), and U(VI). The concentration of the sample is calculated either by solving three simultaneous Nernst equations, by the Gran plot procedure, or by means of a microprocessor pH meter. Molar concentrations of metal ion up to 2.5 times that of the acid can be tolerated. The method has been applied to analysis of nuclear processing solutions that contain Pu(III), in addition to the ions listed above.
Date: May 29, 2001
Creator: Baumann, E.W.
Partner: UNT Libraries Government Documents Department

Preparation and Properties of Nitrate-Deficient Gadolinium Nitrate Solutions

Description: Because of the high neutron absorption cross sections of some gadolinium isotopes, gadolinium salts in solution are used to control nuclear reactivity in aqueous systems. The present studies concern the preparation and analysis of nitrate-deficient solutions, the effect of time and gamma radiation on their stability, and the determination of the solubility of gadolinium hydroxide in H2O and D2O.
Date: March 15, 2001
Creator: Baumann, E.W.
Partner: UNT Libraries Government Documents Department

Determination of Stability Constants of Hydrogen and Aluminum Fluorides with a Fluoride-Selective Electrode

Description: The ability to directly determine free fluoride ion concentration (or mean activity) simplifies gathering and interpretation of experimental data for studies of metal complexes. In this work, the new lanthanum fluoride electrode was used to measure free fluoride ion in an investigation of the hydrogen-fluoride and aluminum-fluoride systems in NH4NO3.
Date: January 6, 2003
Creator: Baumann, E.W.
Partner: UNT Libraries Government Documents Department

Standard addition method for free acid determination in solutions with hydrolyzable ions

Description: The free acid content of solutions containing hydrolyzable ions has been determined potentiometrically by a standard addition method. Two increments of acid are added to the sample in a 1M potassium thiocyanate solution. The sample concentration is calculated by solution of three simultaneous Nernst equations. The method has been demonstrated for solutions containing Al/sup 3 +/, Cr/sup 3 +/, Fe/sup 3 +/, Ni/sup 2 +/, Th/sup 4 +/, or UO/sub 2//sup 2 +/ with a metal-to-acid ratio of < 2.5. The method is suitable for determination of 10 ..mu..moles acid in 10 mL total volume. The accuracy is verifiable by reasonable agreement of the Nerst slopes found in the presence and absence of hydrolyzable ions. The relative standard deviation is < 2.5 percent.
Date: January 1, 1981
Creator: Baumann, E.W.
Partner: UNT Libraries Government Documents Department

Reactor service life extension program

Description: A review of the Savannah River Site production reactor systems was initiated in 1980 and led to implementation of the Reactor Materials Program in 1984 to assess reactor safety and reactor service life. The program evaluated performance of the reactor tanks, primary coolant piping, and thermal shields, components of welded construction that were fabricated from Type 304 stainless steel. The structural integrity analysis of the primary coolant system has shown that the pressure boundary is not susceptible to gross rupture, including a double ended guillotine break or equivalent large area bank. Residual service life is potentially limited by two material degradation modes, irradiation damage and intergranular stress corrosion cracking. Analysis of the structural integrity of the tanks and piping has shown that continued safe operation of the reactors for several additional decades is not limited by the material performance of the primary coolant system. Although irradiation damage has not degraded material behavior to an unacceptable level, past experience has revealed serious difficulties with repair welding on irradiated stainless steel. Stress corrosion can be mitigated by newly identified limits on impurity concentrations in the coolant water and by stress mitigation of weld residual stresses. Work continues in several areas: the effects of helium on mechanical behavior of irradiated stainless steel; improved weld methods for piping and the reactor tanks; and a surveillance program to track irradiation effects on the tank walls.
Date: January 1, 1990
Creator: Caskey, G.R.; Sindelar, R.L.; Ondrejcin, R.S. & Baumann, E.W.
Partner: UNT Libraries Government Documents Department

Colorimetric determination of Fe sup 2+ /Fe sup 3+ ratio in radioactive glasses

Description: In the vitrification of nuclear wastes, the Fe{sup 2+}/Fe{sup 3+} ratio in the glass is a measure of the redox properties of the glass melt. It is necessary to measure this ratio to ensure that the melt redox properties are suitable for the glass melter. A colorimetric method for measuring the Fe{sup 2+}/Fe{sup 3+} ratio in highly radioactive glasses was developed and tested remotely in a shielded cell. The tests were performed on glasses similar in composition and radioactivity to those that will be produced in the Savannah River Site Defense Waste Processing Facility. The first step of the method is dissolution of finely crushed glass with a hydrofluoric/sulfuric acid mixture with ammonium vanadate added to preserve the Fe{sup 2+} content of the glass during the dissolution. Boric acid is then added to complex fluoride and to destroy iron-fluoride complexes. After adjusting the solution to pH 5, FerroZine{sup TM} (trademark of the Hach Company, Loveland, CO) reagent is added to form a magenta-colored complex with Fe{sup 2+}. The absorbance at 562 nm is measured by using a fiber optic-coupled photodiode array spectrophotometer. Ascorbic acid is then used to reduce all the iron in solution to Fe{sup 2+} and the absorbance is again measured. The difference in absorbance measurements corresponds to the Fe{sup 3+} in the sample and the Fe{sup 2+}/Fe{sup 3+} ratio can be calculated.
Date: January 1, 1992
Creator: Coleman, C.J.; Baumann, E.W. & Bibler, N.E.
Partner: UNT Libraries Government Documents Department

Chemical aspects of gadolinium nitrate as soluble nuclear poison in Savannah River Plant reactors

Description: The aqueous solution chemistry of gadolinium nitrate was studied to identify conditions that interfere with successful cleanup of gadolinium in Savannah River Plant reactor systems. Injecting a gadolinium nitrate solution into the D/sub 2/O coolant-moderator constitutes a supplementary mode of reactor shutdown. The resulting approximately 0.001M gadolinium nitrate solution is then deionized by recirculation through mixed-bed ion exchange resins before reactor operation is resumed.
Date: January 1, 1978
Creator: Baumann, E.W.
Partner: UNT Libraries Government Documents Department

Colorimetric determination of Fe{sup 2+}/Fe{sup 3+} ratio in radioactive glasses

Description: In the vitrification of nuclear wastes, the Fe{sup 2+}/Fe{sup 3+} ratio in the glass is a measure of the redox properties of the glass melt. It is necessary to measure this ratio to ensure that the melt redox properties are suitable for the glass melter. A colorimetric method for measuring the Fe{sup 2+}/Fe{sup 3+} ratio in highly radioactive glasses was developed and tested remotely in a shielded cell. The tests were performed on glasses similar in composition and radioactivity to those that will be produced in the Savannah River Site Defense Waste Processing Facility. The first step of the method is dissolution of finely crushed glass with a hydrofluoric/sulfuric acid mixture with ammonium vanadate added to preserve the Fe{sup 2+} content of the glass during the dissolution. Boric acid is then added to complex fluoride and to destroy iron-fluoride complexes. After adjusting the solution to pH 5, FerroZine{sup TM} (trademark of the Hach Company, Loveland, CO) reagent is added to form a magenta-colored complex with Fe{sup 2+}. The absorbance at 562 nm is measured by using a fiber optic-coupled photodiode array spectrophotometer. Ascorbic acid is then used to reduce all the iron in solution to Fe{sup 2+} and the absorbance is again measured. The difference in absorbance measurements corresponds to the Fe{sup 3+} in the sample and the Fe{sup 2+}/Fe{sup 3+} ratio can be calculated.
Date: May 1, 1992
Creator: Coleman, C. J.; Baumann, E. W. & Bibler, N. E.
Partner: UNT Libraries Government Documents Department

Reactor service life extension program

Description: A review of the Savannah River Site production reactor systems was initiated in 1980 and led to implementation of the Reactor Materials Program in 1984 to assess reactor safety and reactor service life. The program evaluated performance of the reactor tanks, primary coolant piping, and thermal shields, components of welded construction that were fabricated from Type 304 stainless steel. The structural integrity analysis of the primary coolant system has shown that the pressure boundary is not susceptible to gross rupture, including a double ended guillotine break or equivalent large area bank. Residual service life is potentially limited by two material degradation modes, irradiation damage and intergranular stress corrosion cracking. Analysis of the structural integrity of the tanks and piping has shown that continued safe operation of the reactors for several additional decades is not limited by the material performance of the primary coolant system. Although irradiation damage has not degraded material behavior to an unacceptable level, past experience has revealed serious difficulties with repair welding on irradiated stainless steel. Stress corrosion can be mitigated by newly identified limits on impurity concentrations in the coolant water and by stress mitigation of weld residual stresses. Work continues in several areas: the effects of helium on mechanical behavior of irradiated stainless steel; improved weld methods for piping and the reactor tanks; and a surveillance program to track irradiation effects on the tank walls.
Date: December 31, 1990
Creator: Caskey, G. R.; Sindelar, R. L.; Ondrejcin, R. S. & Baumann, E. W.
Partner: UNT Libraries Government Documents Department