METHOD FOR RECOVERY OF AMMONIA-CONTAINING RADIOACTIVE WASTES Russian patent published in 2001 - IPC

FIELD: recovery of liquid radioactive wastes at nuclear power plants and other nuclear enterprises. SUBSTANCE: method involves evaporation of wastes in alkali environment, cooling down of secondary steam, and its cleaning by means of exchangers. Ammonia condensate is evaporated and at the same time treated with nitrites prior to passing it through ion exchangers. Reaction between ammonia and nitrite ions produces nitrogen and water at boiling temperature. Nitrogen is passed through special gas cleaners wherein it is cleaned of radionuclides and then exhausted into the atmosphere. Prior to evaporation acidity of ammonia condensate is corrected to pH = 2.7. As soon as salt and corrosive anions content of bottoms is brought to specified limit (end of process) evaporation is continued for several hours more while adding ammonia-free condensate to the process. Ammonia-free condensate produced in the process is conveyed to ion-exchanger. Ammonia condensate may be evaporated without correcting its pH. When this is the case, secondary-steam condensate produced in the process is conveyed to initial stage of process and evaporation procedure is repeated. EFFECT: enhanced efficiency of ammonia extraction from wastes; reduced requirement of chemical agents for exchange filter reconditioning and waste recovery. 5 cl, 2 dwg, 3 tbl