SELECTING OF MATRIX COMPOSITION FOR IMMOBILIZATION OF IRRADIATED FUEL OF THE IGR REACTOR

Impulse Graphite Reactor (IGR) is a unique nuclear installation namely research reactor with the core consisting of uranium-graphite fuel elements with 90% enrichment by U²³⁵. Possible immobilization of the first core taken from the reactor in 1967 is studied here as part of the IGR reactor conversion to low-enriched uranium fuel. Irradiated fuel is related to the category of mediumactive waste according to the content of beta-emitters. Expected value of highly-enriched uranium fuel (HEU) burnup rate was less than 1 % mass. The experts from the Institute of Atomic Energy (IAE) proposed the way how to immobilize irradiated IGR reactor fuel into the cement matrix. First, the fuel is suggested to dilute with depleted uranium in order to lower the enrichment up to the <20 mass. % by U²³⁵. The properties of the matrix should meet the engineering criteria ruled by international and national standards. So, according to aforesaid, The IAE team is facing an actual problem of selection the matrix and understanding its characteristics.
The work was aimed at selection of composition of cement mortar for making robust matrix to immobilize irradiated IGR reactor fuel.
The paper describes techniques and results of the time identification (start) of solidification, gradual volume change, water separation, velocity and uniform cement mortar.

1. Ehkologicheskii kodeks Respubliki Kazakhstan: ofit. (In Russian).

2. Izmerenie moshchnosti izlucheniya ot obluchennogo yadernogo topliva reaktora IGR i analiz radionuklidnogo sostava OYAT: otchet o NIR / A.G. Korovikov. – Kurchatov: Filial IAEH RGP NYATS RK, 2017. – № 36-100-05/375 vn. ot 01.03.17. (In Russian).

3. Nuclear Waste Forms / S.V. Stefanovsky, S.V. Yudintsev, R. Giere, G.R. Lump-kin // Energy, Waste and the Environment: A Geological Perspective. Geological Society, London. – 2004. – Special Publication. – V. 236. – P. 37-63. (In English).

4. An introduction to nuclear waste immobilization / M.I. Ojovan, W.E. Lee. – Second Edition. Elsevier. (In English).

5. Tekhnologicheskie i organizatsionnye aspekty obrashcheniya s radioaktivnymi otkhodami // IAEA-TCS-27. – Vena. – 2005. (In Russian).

6. Pravila organizatsii sbora, khraneniya i zakhoroneniya radioaktivnykh otkhodov i otrabotavshego yadernogo topliva, utv. prikazom Ministra ehnergetiki Respubliki Kazakhstan ot 8 fevralya 2016 goda № 39 (s izmeneniyami ot 21.09.2020 g.). (In Russian).

7. ST RK 3723-2021. Otkhody radioaktivnye tsementirovannye. Obshchie tekhnicheskie trebovaniya. https://online.zakon.kz/Document/?doc_id=33712184. (In Russian).

8. Obzor rezul'tatov issledovanii impul'snogo reaktora IGR [Ehlektronnyi resurs] / Gorin N.V., Kandiev YA.Z., Shcherbina A.N. i dr. – 2003. URL: https://www.nnc.kz/media/bulletin/files/xOzRdhY81A.pdf (data obrashcheniya: 04.11.2023). (In Russian).

9. Institut atomnoi ehnergii natsional'nogo yadernogo tsentra respubliki Kazakhstan – 60 let: Kniga / Pod red. Batyrbekova EH.G. i Skakova M.K. – Kokshetau: KF «KokshetaU», 2018. – 51 s. (In Russian).

10. Reaktor IGR. Razbavlenie vysokoobogashchennogo uranovogo topliva / Batyrbekov EH.G., Koyanbaev E.T., Gnyrya V.S., Kotlyar A.N. // Chelovek. Ehnergiya. Atom. – 2020. – № 1(33). – S. 23-27. (In Russian).

11. Impul'snyi grafitovyi reaktor IGR / I.V. Kurchatov, S.M. Feinberg, N.A. Dollezhal' i dr. // Atomnaya Ehnergiya. – 1964. – T. 17, vyp. 6. – S. 463-474. (In Russian).

12. Dedik T. Russian Research Reactor Fuel Return Program starts shipping fuel to Russia [Ehlektronnyi resurs] / T. Dedik, I. Bolshinsky, A. Krass – 2003. – URL: https://inis.iaea.org/collection/NCLCollectionStore/ Public/35/066/35066230.pdf (data obrashcheniya 16.12.2023 g.). (In English).

13. Malinina G.A. Stroenie i gidroliticheskaya ustoichivost' samarii, gafnii i uransoderzhashchikh steklokristallicheskikh materialov dlya immobilizatsii tverdykh radioaktivnykh otkhodov: dis. …kand.khim.nauk: 05.17.02 / Malinina Galina Aleksandrovna; FGUP «RADON». – M., 2016. – 117 s. (In Russian).

14. Apseh V.A. Yadernye tekhnologii: uchebnoe posobie / V.A. Apseh, A.N. Shmelev – M.: MIFI, 2008. – 128 s. (In Russian).

15. Encapsulation of HEU / Graphite Particulate – Potential Formulations and Other Considerations, DEC_0988_A, S Farris, Sellafield LTD, 2020. (In English).

16. Tumanov YU.N. Plazmennye, vysokochastotnye, mikrovolnovye i lazernye tekhnologii v khimiko-metallurgicheskikh protsessakh: kniga / YU.N. Tumanov. – M.: Fizmatlit, 2010. – 958 s. (In Russian).

17. R.Z. Rakhimova Kompozitsizionnye vyazhushchie dlya immobilizatsii toksichnykh i radioaktivnykh otkhodov / N.R. Rakhimova, R.Z. Rakhimov, O.V. Stoyanov // Vestnik Kazanskogo tekhnologicheskogo universiteta. – 2013. № 4. – T. 16. – S. 175-182. (In Russian).

18. GOST 310.4-81. Tsementy. Metody opredeleniya predela prochnosti pri izgibe i szhatii. M.: Izdvo standartov, 2003. – 11 s. (In Russian).

19. GOST 310.6-85. Tsementy. Metody opredeleniya vodootdeleniya. M.: Izd-vo standartov, 2003. – 2 s. (In Russian).

20. GOST 310.3-76. Tsementy. Metody opredeleniya normal'noi gustoty, srokov skhvatyvaniya i ravnomernosti izmeneniya ob"ema. M.: Izd-vo standartov, 2003. – 6 s. (In Russian).

21. GOST 10180-2012. Betony. Metody opredeleniya prochnosti po kontrol'nym obraztsam. M.: Izdvo standartov, 2018. – 32 s. (In Russian).