Section 1 IntroductionIn June of 1987, the Haste Management Project Office (WMPO) of the Department of Energy conducted a special audit of the activities of the Nevada Nuclear Waste Storage Investigation (NNWSI) Project at Liverrnore. Observation No. 1 of the audit report (WMPO Audit S-87-1) stated that "The rationale for use of Well 3-13 water as the basis for the reference criteria for NNWSI Project activity (until water samples from the unsaturated zone are available) is not clear." A brief reply to that observation was given by the NNWSI Project staff, citing discussions of the justification for using J-I3 water in the Yucca Mountain Environmental Assessment Report Q), which in turn outlines some of the relevant literature on this point. However, it has been noted that there never has been a comprehensive, well-documented examination of the basis for the use of J-13 water in the nuclear waste storage investigations.The management of the NNWSI Project at Livermore therefore asked that a committee be formed to review more thoroughly the question of the validity of the use of J-13 water as a reference material. This committee was composed of scientists who had expertise in the requisite technical areas, but who were not involved in the current activities of the NNWSI Project. The committee was also charged with reexamining and recommending, in the light of the assessment of the technical validity of the use of J-13 water, the NNWSI quality-assurance level to which future activities involving J-13 water should be assigned. This document is a report of these findings.It was apparent to the committee from the outset that the overall question of the rationale for use of J-13 water extends beyond just the Livermore studies, which mostly have dealt with phenomena in the so-called "near-field" region of the repository, which is the region that will be influenced by heat from the radioactive waste. Thus far, the Livermore work has focussed mostly on experimental and computer-modeling studies of rock/water, metal-alloy/water, and waste-form/water interactions. Other investigators, particularly at Los Alamos National Laboratory, have been concerned with the behavior, e. g., transport, of radionuclides in the ground waters outside the immediate Yucca Mountain area of the repository site. Thus the question of the validity of J-13 water as a reference material i f a more global one, and should be asked -1.1-in terms of the NNWSI program as a whole, and not just with respect to waters in the unsaturated zone as was done by the WMPO audit committee. In this sense, we may have enlarged the scope of the enquiry somewhat, but we believe it has led to a more coherent, if not more satisfying answer. Water from the J-13 well has been used experimentally in waste storage studies for at least ten years. Beginning in about 1977 (2) at Los Alamos, the ready availability of 0-13 water and its known similarity to the other Nevada Test Site ground waters made it a natural choice as a surrogate water for experiments designed to measure phe...
An electrically regenerated separation process has been developed for removing unwanted ions from aqueous waste streams as a minimally polluting, energy-efficient, and potentially cost-effective alternative to ion exchange, reverse osmosis, electrodialysis, and evaporation. Ground water containing various anions and cations is passed through a stack of carbon aerogel electrodes, each having a very high specific surface area (400−1100 m2 g-1) and exceptionally low electrical resistivity (≤40 mΩ·cm). After polarization of the stack, impurity ions are removed from the electrolyte by the imposed electric field and adsorbed on the electrode surfaces. Field tests have shown that hexavalent chromium in the form of HCrO4 -/CrO4 2-/Cr2O7 2- can be selectively removed from contaminated ground water with a 530 ppm total dissolved solids (TDS) background. The concentration of Cr(VI) can be lowered from 35 to 2 ppb, well below the acceptable level for the regulatory surface water discharge limit of 11 ppb. The mechanism for Cr(VI) separation involves chemisorption on the carbon aerogel anode, a process that can be reversed by cathodic polarization. Cr(VI) removal is not based upon simple double-layer charging.
Division ofAnalytical Chemistry, Winter Meeting, ACS, Phoenix, Ariz., January 1966. This work was supported by the U. S. Atomic Energy Commission Under Contract No. AT(10-l)-205 through the Idaho Operations Office.
ound for each compound with the theoretical percentage >ives an indication of absolute accuracy. In all cases, the ;alifornium-252 method shows greater accuracy and precision han the spectrophotometric method.apor. This fact, coupled with the possibility of low-level xygen contamination in the samples (e.g., CaO in CaF2) and degree of uncertainty in the oxygen blank values for indiidual polyethylene sample carriers may account for the slightly ositive values obtained for non-oxygen-containing comounds. SUMMARYA method has been developed for the nondestructive analyis of fluorine by neutron activation with a californium-252 iotopic source.About 1 gram of sample is required and the nalysis time is about 30 min per sample. A comparative study has demonstrated the method to be superior in precision and accuracy to an established spectrophotometric method although a much larger sample is required (1 gram vs. 10 mg).If one can accept a factor 2 lower precision, the required sample size could be reduced to 250 mg. The sample size may be further reduced by another factor of 3 by modifying the californium-252 source holder so that sources are closer to the sample. Although analysis time for the classical method is equivalent, the method consumes the sample. Finally, in conjunction with 14-MeV neutron activation, an oxygen analysis method has also been developed, which eliminates the fluorine interference in routine oxygen determinations. Agreement of the results with theory has been established for a series of compounds with known composition.
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