ESTIMATION OF LONG CONSERVATION POSSIBILITY OF IRRADIATED CONSTRUCTIONAL ELEMENTS WITH ZIRCONIUM ALLOY DURING DECOMMISSIONING OF URANIUM-GRAPHITE REACTOR

The paper deals with the constructional elements from zirconium alloys used for manufacturing of technological channels in High Power Channel-type Reactors and Industrial Uranium-Graphite reactors. For estimation of safety handling with constructional elements with zirconium alloys, the paper investigates radionuclide composition, contamination level o f the irradiated zirconium alloy (E110), reliability of radionuclides fixing and impeding properties of a barrier material from mix o f clay in relation to the radionuclides identified in an alloy. Waste with irradiated zirconium alloy (1-1,5% mas. niobium) contain neutron-activation product: 93mNb and long-life rad ionuclides 94Nb and 93Zr. Also there are 60Co, 137Cs, 90Sr and actinides in the alloy. During experiment leaching of zirconium and niobium isotopes from alloy E110 were not detected. Significant rates of leaching were observed only for 60Co and 137Cs, which were in residues on internal surface of technological channels. It was proved, that sorptive properties of clay-content material, which used to during creating of placement of long-term conservation of Industrial Uranium-Graphite reactors graphite stack, provide localization of radionuclides in case of it outcrop in a barrier material from the irradiated alloy of zirconium. It occurs because radionuclides are sorbed by a barrier material.

1. Espartero A.G., Suarez J.A., Rodriguaez G. Radiochemical analysis of 93Zr. Applied Radiation and Isotopes, 2002, vol. 56, pp. 41–46 (in Eng.).

2. Parfenov B.G., Gerasimov V.V., Venediktova G.I. Korroziâ cirkoniâ i ego splavov. Moscow: Atomizdat Publ., 1967 (in Russ.).

3. Lastman B., Kerze F. Metallu rgiâ cirkoniâ. Moscow: Izd-vo inostr. lit. Publ., 1959 (in Russ.).

4. Hacker M., Properties of Reastor Materials and Effects of Radiation damage. Butterworths, 1962 (in Eng.).

5. Bardina N.G., Lukovtsev P.D. Kinetika èlektrohimičeskih processov na okislennyh èlektrodah. Ž. fiz. himii, 1963, vol. 37, pp. 268–271 (in Russ.).

6. Haskerman N., Sesil O.V. The Electrochemical Polarization of Zr in Neutral Salt So lution. J. Electrochem. Soc., 1954, vol. 101, pp. 419–425 (in Eng.).

7. Adler Flitton M.K., Yoder T.S. Long-Term Underground Corrosion of Stainless Steels. Inl/con-06- 11963 preprint NACE. March, 2007 (in Eng.).

8. Adler Flitton M.K., Yoder T.S. Long Term Corrosion/ Degradation Test First Year Results. INEEL/EXT-99-00678, Idaho National Engineering and Environmental Laboratory, Bechtel BWXT Idaho, LLC, Idaho Falls, Idaho (in Eng.).

9. Adler Flitton M.K., Yoder T.S. Long Term Corrosion/ Degradation Test Third-Year Results. INEEL/EXT-01-00036, Idaho National Engineering and Environmental Laboratory, Bechtel BWXT Idaho, LLC, Idaho Falls. 2001 (in Eng.).

10. Mizia R.E., Adler Flitton M.K., Yoder T.S. Underground Corrosion of Activated Metals in an Arid Vadose Zone Environment. INEEL/CON-01-01450 PREPRINT. April, 2002 (in Eng.).

11. Kay M., Adler Flitton M.K., Yoder T.S. Twelve Year Study of Underground Corrosion of Activated Metals. NACE International Corrosion Conference and Expo — March, 2012 (in Eng.).

12. Mihailovsky Yu.N. Issledovanie èlektrohimičeskih processov počvennoj korro zii metallov: Ph.D. (chemistry) diss. Moscow: IFH AN USSR, 1957 (in Russ.).

13. Izmestiev A., Pavliuk A., Kotlyarevsky S. Application of void-free filling technology for additional safety barriers creation during uranium-graphite reactors decommissioning. Advanced Materials Research, 2015, vol. 1084, pp. 613–619 (in Eng.).

14. Marey A.N. Sanitarnaâ ohrana vodoemov. Moscow: Atomizdat Publ., 1976 (in Russ.).