482 Matching Results

Search Results

Advanced search parameters have been applied.

Long-term performance assessment of grouted phosphate/sulfate waste from N Reactor operations

Description: Phosphate sulfate waste (PSW) is a low-level liquid generated by activities associated with N Reactor operations. The waste will be mixed with dry solids and permanently disposed of as a cementitious grout in sub-surface concrete vaults at Hanford's 200-East Area. Categories of scenarios were analyzed that could cause humans to be exposed to radionuclides and chemicals from the grouted waste include contaminated groundwater and direct intrusion. In the groundwater scenario, contaminants are released from the buried grout monoliths, then eventually transported via the groundwater to the Columbia River. As modeled, the contaminants are assumed to leach out of the monoliths at a constant rate over a 10,000-year period. The other category of exposure involves intruders who inadvertently contact the waste directly, either by drilling, excavating, or gardening. Long-term impacts that could result from disposal of PSW grout were expressed in terms of incremental increases of chemical concentrations in the groundwater and surface waters, and radiation doses. None of the calculated impacts exceeded the corresponding regulatory limits set by Washington State, the Department of Energy, or the Nuclear Regulatory Commission. 38 refs., 17 figs., 27 tabs.
Date: April 1, 1987
Creator: Sewart, G.H.; Farris, W.T.; Huizenga, D.G.; McMakin, A.H.; Streile, G.P. & Treat, R.L.
Partner: UNT Libraries Government Documents Department

Leach tests on grouts made with actual and trace metal-spiked synthetic phosphate/sulfate waste

Description: Pacific Northwest Laboratory conducted experiments to produce empirical leach rate data for phosphate-sulfate waste (PSW) grout. Effective diffusivities were measured for various radionuclides ({sup 90}Sr, {sup 99}Tc, {sup 14}C, {sup 129}I, {sup 137}Cs, {sup 60}Co, {sup 54}Mn, and U), stable major components (NO{sub 3}{sup {minus}}, SO{sub 4}{sup 2{minus}}, H{sub 3}BO{sub 3}, K and Na) and the trace constituents Ag, As, Cd, Hg, Pb, and Se. Two types of leach tests were used on samples of actual PSW grout and synthetic PSW grout: the American Nuclear Society (ANS) 16.1 intermittent replacement leach test and a static leach test. Grout produced from both synthetic and real PSW showed low leach rates for the trace metal constituents and most of the waste radionuclides. Many of the spiked trace metals and radionuclides were not detected in any leachates. None of the effluents contained measurable quantities of {sup 137}Cs, {sup 60}Co, {sup 54}Mn, {sup 109}Cd, {sup 51}Cr, {sup 210}Pb, {sup 203}Hg, or As. For those trace species with detectable leach rates, {sup 125}I appeared to have the greatest leach rate, followed by {sup 99}Tc, {sup 75}Se, and finally U, {sup 14}C, and {sup 110m}Ag. Leach rates for nitrate are between those for I and Tc, but there is much scatter in the nitrate data because of the very low nitrate inventory. 32 refs., 6 figs., 15 tabs.
Date: October 1, 1989
Creator: Serne, R.J.; Martin, W.J.; LeGore, V.L.; Lindenmeier, C.W.; McLaurine, S.B.; Martin, P.F.C. et al.
Partner: UNT Libraries Government Documents Department