Composition and Corrosiveness of Low-Activity Waste Supernates Stored at the Savannah River Plant.

摘要

Stress corrosion appears unlikely on the basis of (1) a statistical correlation between mild steel elongation and supernate composition and (2) measured polarization of steel in actual LAW. According to the statistical correlation,the tanks should not crack. Furthermore,the polarization data shows the steel acts as an active-passive metal,and the open-circuit potentials are outside the range of those reported for pure sodium nitrate. The LAW supernates were analyzed in October 1975from four F-Area tanks and three H-Area tanks. Concentrations of major constituents (Na exp + ,OH exp - ,NO sub 3- ,NO sub 2- ,and Al(OH) sub 4- ) are much higher in F-Area supernates because F-Area LAW appears to be in equilibrium with salt in the tanks. Minimum concentrations of major constituents in H-Area LAW are low because one tank (23H) contains water from a fuel storage basin and wastes from regenerating ion exchange resins. Other nonradioactive constituents that were determined include SO sub 42- ,CO sub 32- ,PO sub 43- ,CrO sub 42- ,Cl exp - , F exp - , U,Fe, K exp + ,and Ca exp 2+ . Radionuclides determined included exp 137Cs,exp 90Sr,and exp 238-239Pu. Cesium-137was the major gamma emitter;its activity was as high as 10exp 9dis/(min)(ml). Activities of exp 90Sr (beta) and exp 238-239Pu (alpha) were all very low (10exp 3 - 10exp 4dis/(min)(ml)). (ERA citation 02:015979)