Samples of vapor obtained in May 1994 from the headspace of the Hanford single-shell waste storage tank 24 1-C-103 were analyzed for selected inorganic compounds at Pacific Northwest Laboratory. The work was performed to provide concentration information supporting safety and toxicological evaluations. The vapor samples were passed through analyte-specific solid sorbent traps which held the compounds by chernisorption until analysis. Samples were analyzed to determine the concentrations of ammonia, nitric oxide, nitrogen dioxide, sulfur oxides, and hydrogen cyanide. Samples were also analyzed to provide information on the total mass concentration of vapors in the headspace. A summary of results is shown in Table 1. Throughout the multi-week sample job, average ammonia concentrations were uniform and ranged between 296 and 3 10 ppmv. The actual ammonia concentrations were more than 10-fold greater than the recommended exposure limit (REL) of 25 ppmv. The results of nitric oxide, sulfur oxides, and hydrogen cyanide samples were-2,10.02, and 10.04 ppmv, respectively, and were less or much less than the recommended exposure levels. The concentration of nitrogen dioxide was subject to potential sampling and analytical errors, but was estimated to be less than or much less than 0.4 ppmv. Only the nitrogen dioxide results failed to meet the target analytical detection limit of one-tenth of the REL. Fifty of 55 inorganic samples yielded an average mass concentration of 42.1 f 2.7 mg/L. A series of 10 ammonia samples, also supported by gravimetric analyses, showed no sampling bias occurred between samples obtained from different sample ports. Company (WHC) provided technical guidance by issuing Letters of Instruction and Sampling and

This report was .prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, express or implied, or assumes any legal liability or responsibiiity for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document.

No abstract

Even though the interest in the corrosion of radwaste tanks goes back to the mid-1940 1 5 when waste storage was begun, and a fair amount of corrosion work has been done since then, the changes in processes and waste types have outpaced the development of new data pertinent to the new double shell tanks. As a consequence, Pacific Northwest laboratory {PNL) began a development of corrosion data on a broad base of waste compositions in 1980. The objective of the program was to provide operations personnel with corrosion rate data as a function of waste temperature and composition. The work performed in this program examined A-537 tank steel in Double Shell Slurry and Future PUREX Wastes, at temperatures between 40 and 180°C as well as in Hanford Facilities Waste at 25 and 50°C. In general, the corrosion rates were less than 1 mpy (0.001 inch/yr) and usually less than 0.5 mpy. Excessive corrosion rates (> 1 mpy) were only found in dilute waste compositions or in concentrated caustic compositions at temperatures above 140°C. Stress corrosion cracking was only observed under similar conditions. The results are presented as polynomial prediction equations with examples of the output of existing computer codes. The codes are not provided in the text but are available from the authors.

A suite of physical and chemical analyses has been performed in support of activities directed toward the resolution of an Unreviewed Safety Question concerning the potential for a floating organic layer in Hanford waste tank 241-C-103 to sustain a pool fire. The analysis program was the result of a Data Quality Objectives exercise conducted jointly with staff from Westinghouse Hanford Company and Pacific Northwest Laboratory (PNL). The organic layer has been analyzed for flash point, organic composition including volatile organics, inorganic anions and cations, radionuclides, and other physical and chemical parameters needed for a safety assessment leading to the resolution of the Unreviewed Safety Question. The aqueous layer underlying the floating organic material was also analyzed for inorganic, organic, and radionuclide composition, as well as other physical and chemical properties. This work was • conducted to PNL Quality Assurance impact level III standards (Good Laboratory Practices).°.°1 Peroxides Less than 2.5 gEquivalent/g Nitroalkanes No indication of nitroalkanes by RSST(a) experiment; less than 2 [tmol/g by infrared analysis Density 0.876 g/mL at 25°C, 0.868 g/mL at 44°C Viscosity 4 cP at 25°C, 2.5 cP at 40°C Gross alpha, beta Alpha = 547 pCi/g Beta = 1.05 x 106 pCi/[g 90Sr 5.5 x 105 pCi/g Alpha emitters 238pu = 90.2, 239+240pu = 194, 241Am = 179 (pCi/[g) Gamma emitters 6°Co = 7.45 x 10-4, 137Cs = 4.13 x 10-2, 154Eu = 3.17 x 10"4, 155Eu = 3.15 x 10.4' 241Am = 2.11 x 10.4 (_tCi/[g) aa Water content 1.31 wt% Ammonia 24 lxg NH3/g IC F, Cl, NO2, NO3, SO4, all <50 _tg/g ICP/AES Ag = 0.90, Al = 1.8, B = 11, Ca = 2.0, (2% HNO3 leach) Cd = 2.1, Cu = 2.2, Fe = 0.33, Na = 70, Ni = 9.9, P = 605 (_t_g) (a) RSST = Reactive system screening tool vi Contents

In solutions containing both oxygen and one of the metal ions Zn+1 2 3, Sr+2, TI+, Y+3, Cd+2, a new polarographic reduction wave was observed at potentials less cathodic than that required to reduce the most easily reducible species (either the metal ion or the oxygen) in the sample. The variation of the height of this new wave was investigated as a function of the concentration of oxygen and the various metal ions. The results of this study made possible a determination of the stoichiometry of the process responsible for the new wave.Controlled potential coulometry and controlled potential electrolysis were used to obtain information about the reduction process. The reduction products, prepared by electrochemical methods, were found to be the superoxides of zinc, strontium, and thallium; and the peroxides of cadmium and yttrium.The effect of alkali and alkaline earth metal ions on the polarographic reduction of oxygen in dimethylsulfoxide (DMSO) solutions was reported (7). The reduction waves were markedly dependent upon the cation composition of the test solution. Peover (2) has reported similar type findings for the polarographic reduction of several quiñones in dimethylformamide. Our earlier work had indicated that this shifting of the waves was quite complex and suggested that the metal ion was possibly participating in some type of catalytic reduction of the oxygen. Preliminary investigations with added zinc salts showed a somewhat similar shifting of the waves along with changes in the height of the shifted wave as a function of the zinc ion concentration. The purpose of this investigation was to examine the effect of added metal ions in more detail and, if possible, electrochemically produce and identify the reduction products. EXPERIMENTAL Materials. The DMSO was obtained from the Matheson Company. This and the other chemicals were used as described previously (7). The nitrates of zinc, cadmium, strontium, thallium, and yttrium were of reagent grade and used without further purification.Stock solutions of the metal salts were prepared in DMSO. The zinc, cadmium, strontium, and yttrium solutions were standardized by complexometric titrations with ethylenediaminetetraacetic acid disodium salt. The thallous solution was standardized by amperometric titration with potassium iodide.Apparatus. A three-electrode polarograph of the ORNL type described by Kelley, Jones, and Fisher (3) was used to record all polarograms. The use of three-electrode polarography resulted in improved polarograms when compared to conventional two-electrode polarograms. The slope of the E vs. logOdi)/i plots for the first reduction wave of oxygen was found to be 61 mV.

In Fiscal Year (FY) 1995, staff at the Vapor Analytical Laboratory (VAL) at Pacific Northwest National Laboratory (PNL) performed work in support of characterizing the vapor composition of the headspaces of radioactive waste tanks at the Hanford Site in Southeastern Washington. The work was supported by the Westinghouse Hanford Company (WHC) Tank Waste Remediation System ("WRS) Characterization Program and the U.S. Department of Energy's Richland Operations Office (DOEM.,). Work performed included support for technical issues and sampling methodologies, upgrades for analytical equipment, analytical method development, preparation of unexposed samples, dnalyses of tank headspace samples, preparation of data reports, preparation of input for WHC tank characterization reports, and operation of the tank vapor database. Work performed in FY 1995 was a continuation of work initiated with the first vapor sample job, which was performed in December 1993. Progress made in F Y 1995 included completion of sample analyses from all 40 jobs performed during the year, plus back-logged sample sets from jobs performed in F T 1994. Of the

This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsi-S. A. Bryan bility for the accpracy, completeness, or usefulness of any information, apparatus, product, or K.H. POOl process disclosed, or represents that its use would not infringe privately owned rights. Refer-J. D.Matheson ence herein to any specific commercial preduct, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.