Waste Feed Evaporation: Physical Properties and Solubility Determination

Calloway, T.B.

Savannah River Site (S.C.)

关键词: Evaporators;    12 Management Of Radioactive Wastes, And Non-Radioactive Wastes From Nuclear Facilities;    Hydroxides;    Evaporation;    Radioactive Waste Processing;   

DOI  :  10.2172/813628
RP-ID  :  WSRC-TR-2003-00212
RP-ID  :  AC09-96SR18500
RP-ID  :  813628

美国|英语

来源: UNT Digital Library

【 摘 要 】

Caustic adjustment of the UF recycle stream was required to prevent gel formation for the solutions tested. Actual amounts of caustic adjustment required will vary depending on the composition and volume ratios of the UF recycle. The concentration of recycles in the waste feed evaporator as required to blend with waste feed streams to provide a feed to the ultrafiltration process with a supernate specific gravity of 1.22 is feasible. No problems (such as severe foaming) were noted during the lab-scale testing that would preclude operation of the evaporator. The physical properties of the recycles and waste feed blends fit well to correlations based on sodium concentration and temperature. Evaporation of streams containing high levels of insoluble solids may lead to ''bumping'' or other undesirable behavior in the evaporator at insoluble solids. Sodium alumino-silicate solids were not noted in the evaporator feed or concentrate, but NAS did form in the blends of concentrated recycle and waste feeds. Strontium was found to precipitate during neutralization of the acid cleaning solution and remain precipitated during evaporation. Mercury was found to be significantly soluble in Envelope A simulants and the solubility of mercury increased during evaporation. No mercury was detected in the offgas system after evaporation using Envelope A simulants. Mercury was significantly less soluble in a simulant of AZ-102. Filtration of the Envelope A waste simulants was affected by the addition of recycle to the process, but the impact was primarily due to an increase in the amount of insoluble solids in the blended stream compared to the waste feed.