Treatment and conditioning of radioactive organic liquids

Transcription

1 IAEA-TECDOC-656 Treatment and conditioning of radioactive organic liquids Technical manual for the management of

2 The IAEA does not normally maintain stocks of reports in this series. However, microfiche copies of these reports can be obtained from INIS Clearinghouse International Atomic Energy Agency Wagramerstrasse 5 P.O.

3 TREATMENT AND CONDITIONING OF RADIOACTIVE ORGANIC LIQUIDS IAEA, VIENNA, 1992 IAEA-TECDOC-656 ISSN Printed by the IAEA in Austria July 1992

4 FOREWORD The International Atomic Energy Agency (IAEA) has published Technical Reports Series

5 Treatment

6 CONTENTS 1. INTRODUCTION WASTE ARISINGS AND CHARACTERISTICS Liquid organic waste types Oils...

7 1. INTRODUCTION Liquid organic radioactive wastes are generated from the use of radioisotopes in nuclear research centres and in medical and industrial applications. The volume of these wastes is small by comparison with aqueous radioactive wastes,

8 commonly used materials. Scintillation liquids

9 TABLE I. TYPES AND VOLUMES OF CONTAMINATED ORGANIC LIQUIDS IN DIFFERENT COUNTRIES.Member States in Organic Liquids Group

10 Group E Member States that are involved in most or all of the steps of

11 The waste receiving agency defines the information and quality assurance requirements for effective waste management. This is likely to include physical, chemical

12 FIG. Radioactive Wastes Containing long lived Radioisotopes

13

14 Liquid Organic Radioactive Waste \/ Incinerator Off-gases Clean offgas for Discharge via Stack Ash Secondary Waste

15 radioactive species throughout the process, and the incinerator itself must additionally provide containment of the volatile organic wastes and so avoid the formation of unconfined explosive mixtures of gases and vapours. A variety of incinerator types and concepts has been tried throughout the world. In general, incinerators for low level radioactive wastes have proved more successful than

16 To Stack

17 Cooling

18 A- Combustible Gas Monitor /""^ / x Off Gas Propane /^ -r*»,? o»<:> -l^o-'o wer*. Air Combustion Chamber Blower " Main Burner -M- Pump Wall FIG. 5. Liquid feed system to cyclone incinerator, Mound (USA)

19 Silver II electrochemical oxidation process [17] This process offers an alternative oxidation method to incineration that has some parallels with the wet oxidation process described in Section Both processes operate at much lower temperatures than incineration

20 Water A Membrane \l> Carbon Dioxide Separator air > heater 0 Acid Nitric ode Recovery Inorganic Waste Solution A \ <=2" ^Cooler Electro- < chemical Cell Silver Recovery -&* 1 FIG.

21 Phase separation by adduct formation [19-22] Phase separation by adduct formation has been investigated as a pretreatment prior

22 to to Separation Column Solvent Splitting Step : Kerosene ü 11 ltbp(h 3 P0 4 ) x, fc Ä : '!'!! &v : : :: ijij: II; X*X **î*!*î* X'X 1 X'X' i'i'i'i-i'i': - n i Ä: «1 8$: 1 II i i : $: m X'X;. 1 H 2 0 Kerosene (Traces H 3 PO A ) Settler : u 1. :: :; i m m m 11 I ü m ' tti\ :*S: m El ill Wo Coli TBP Pyrolysis Step Torch --K>f-j ^J Solvent Waste TBP-Kerosene (Very Oil) FIG. 8. Simplified flow sheet of the Eurowatt process (three phase system).

23 Karlsruhe Betriebsgesellschaft mbh, Eggenstein Leopoldshafen (WAK), were treated in 50 L batches and the diluent recycled, being free of nitro- and nitrato-compounds. Incineration of condensed diluent and butanol from the hydrolysis was also demonstrated. The process was proposed for the treatment of 30% TBP/diluent, and phase separation was proposed for the treatment of solutions containing 2-20% TBP/diluent. The suggested disposal route for the lower phase from the hydrolysis process containing sodium dibutyl phosphate (DBF), butanol, methanol and water was evaporation of

24 A. Storage

25

26 the liquid will be taken up. This technique has been routinely used for the solidification of radioactive turbine and pump oil [29]. The following main categories

27 Organic Liquid Waste v ( Mix j<- V Water Emulsification (Oil

28

29 4.2. Process selection General This section of the report attempts to provide guidance to Member States in Groups A, B and C in the selection of appropriate processes for treatment of radioactive organic liquid wastes. It is assumed that the differences in volumes, types, and radioisotopes content of wastes for the Member State groups will present different requirements which

30 Option l Scintillation l

31 Option -> Absorption > Immobilization Advantages 1. Simple 2. Cheap 3. Combined use for other wastes -> Absorption > Incineration Oils -> Incineration Wet -> Oxidation

32 W to Dot ion > Immobilization Advantages Simple Cheap Combined use for other wastes > Distillation > Incineration I Destroys 1 1

33

34 The possibility of capacity extension should be provided for in the design of the facility. To prevent radiation exposure to on-site personnel, it is recommended that the interim storage facility should be constructed away from waste treatment plants

35 FIG. 16. Simple hall for interim storage of conditioned radioactive wastes in Chile. 7. PROCESS SAFETY This Section covers the safety aspects which need to be considered in the handling and processing of organic liquid radioactive wastes. The special hazards associated with these wastes are: flammability, toxicity and explosion, as well as radioactivity. These dictate that the receiving and initial handling area

36 Hazard

37 REFERENCES [1] INTERNATIONAL ATOMIC ENERGY AGENCY, Options for the Treatment and Solidification of Organic Radioactive Wastes, Technical Reports Series No. 294, IAEA, Vienna (1989). [2] BAEHR, W., "The treatment of radioactive organic liquid wastes", IAEA Interregional Training Course on Management of Radioactive Wastes, 1987 Kernforschungszentrum Karlsruhe.

38 [16] HOLMAN, D.J., "Process options for treatment of organic-containing ILWs by wet oxidation", Radioactive Waste Management, BNES, London (1989). [17] STEELE, D.F., A novel approach to organic waste disposal, Atom 393 (July 1989). [18] WIECZOREK, H., OSER, B., "Development and active demonstration of acid digestion