O. V. Mykhailov, V. M. Bezmylov
Institute for Safety Problems of Nuclear Power Plants, NAS of Ukraine, 36a, Kirova st., Chornobyl, 07270, Ukraine
Two methodological approaches for radioactive waste (RAW) certification used in RAW management systems in Italy and France, are addressed. Their applicability was assessed in solving certification problem of historical waste accumulated at the Chornobyl NPP in comparison with the standard methods recommended by the IAEA. Testing new methodological approaches was carried out on the example of solid RAW (SRW) of operational origin, which were previously studied for the content of 24 radionuclides within their composition. The procedures for testing researchable methods have used the criteria for SRW acceptance for burial valid in SRW Treatment Plant, which met their current provisions and those ones planned for approval. It was established that the use of quantitative criteria applied in the algorithms of studied methodological approaches for radwaste certification can significantly reduce overestimation degree of summary activity of waste packages by way of removing from the list of difficult-to-measure radionuclides, whose presence can be neglected in view of negligible risk of exceeding the activity limits established for them. The methodological approaches addressed in this work allow optimizing radionuclide contents subject to mandatory measurement, or calculated determination of their activity in waste packages, and can be recommended to solve the problems when characterizing ChNPP’s historical waste transported for their final disposal.
Keywords: radioactive waste, Chornobyl NPP, specific activities, difficult-to-measure radionuclides, key nuclides, certification, scaling factor.
1. OECD (2017). Radiological characterization from a waste and materials. end-state perspective: practices and experience (NEA‑7373). Nuclear Energy Agency of the OECD (NEA), 100 p. Available at: https://www.oecd-nea.org/rwm/pubs/2017/7373-rad-char-pers.pdf.
2. Determination and use of scaling factors for waste characterization in NPP. IAEA Nuclear Energy Series NW-T-1.18. Vienna: IAEA, 2009, 142 р.
3. Criteria for acceptance of waste for burial in specially equipped near-surface repository for solid radwaste (SESRSRW). First stage of SESRSRW operation. Acceptance
of RAW from SSE ChNPP PTLRW and PTSRW for burial in two symmetrical compartments of SESRSRW. Revision 5. Endorsed by acting Director General of State Corporation “UkrSE ‘Radon’”. Chornobyl, 2009, 38 p. (in Ukr.)
4. Mykhailov O. V., Bezmylov V. M., TerziA. K. (2020). Analysis of radionuclide contamination features in solid radwaste of “light” eastern compartment of solid waste repository of Chornobyl NPP. Yaderna Energetyka ta Dovkillia [Nuclear Power and the Environment], vol. 16, no. 1, pp. 40−48.
5. Zaffora B., Magistris M., Saporta G., Chevalier J. (2017). Uncertainty quantification applied to the radiological characterization of radioactive waste. Applied Radiation and Isotopes, vol. 127, pp. 142–149. doi: 10.1016/j.apradiso.2017.06.001.
6. Zaffora B., Magistris M., Chevalier J., Luccioni C., Saporta G., Ulrici L. (2017). A new approach to characterize very-low-level radioactive waste produced at hadron accelerators. Applied Radiation and Isotopes, vol. 122, 141−147. doi: 10.1016/j.apradiso.2017.01.019.
7. Criteria for acceptance of waste for burial in specially equipped near-surface repository for solid radwaste (SESRSRW). KRIII.109–4.023.-2018. Revision 6. Project. Endorsed by acting Director SSE “CERWM”. Chornobyl, 2018, 39 p. (in Ukr.).
8. Strategy and methodology for radioactive waste characterization. IAEA-TECDOC-1537. IAEA, VIENNA, 2007, 182 р.
9. ISO 21238:2007 Nuclear energy — Nuclear fuel technology — Scaling factor method to determine the radioactivity of low- and intermediate-level radioactive waste packages generated at nuclear power plants. Geneva: International Organization for Standardization, 2007.
10. ISO 16966:2013 Nuclear energy — Nuclear fuel technology — Theoretical activation calculation method to evaluate the radioactivity of activated waste generated at nuclear reactors. Geneva: International Organization for Standardization, 2013.
11. Lukauskas D., Plukiene R., Plukis A., Gudelis A., Duskesas G., Juodis L., Druteikiene R., Lujaniene G., Luksiene B., Remeikis V. (2006). Method to determine the nuclide inventory of low-activity waste of the RBMK-1500 reactor. Lithuanian J. Phys., vol. 46, no. 4, pp. 497−503. doi: 10.3952/lithjphys.46413.
12. Plukis A., Remeikis V., Juodis L., Plukiene R., Lukauskas D., Gudeli A. (2008). Analysis of nuclide content in Ignalina NPP radioactive waste streams. Lithuanian J. of Phys., vol. 48, no. 4, pp. 375−379. doi: 10.3952/lithjphys.48409.
13. Mykhailov O. V., Krasnov V. O., Bezmylov V. M. (2019). Theoretical and Practical Aspects in Using Scaling Factor Method to Characterize Operational Solid Radioactive Waste Producible at Nuclear Power Plants. Yaderna Energetyka ta Dovkillia [Nuclear Power and the Environment], vol. 13, no. 1, pp. 52−58.
14. Albertone L., Altavilla M., Marga M., Porzio L., Tozzi G., Tura P. (2019). Control Experiences Regarding Clearable Materials from Nuclear Power Plants and Nuclear Installations: Scaling Factors Determination and Measurements’ Acceptance Criteria Definition. Environments, vol. 11, no. 6, p. 120. doi:10.3390/environments6110120.
15. Zaffora B., Magistris M., Saporta G., La Torre F. (2016). Statistical sampling applied to the radiological characterization of historical waste. EPJ Nuclear Sci. Technol., vol. 2., no. 34, pp. 1−11. doi: 10.1051/epjn/2016031.
16. Mikhailov A. V., Pavljuchenko N. I., Mjasnikov A. V., Terzi A. K., Krasnov V. A. (2019). [Results of radionuclide vectors determination to be used in characterization of SSE NPP’s solid radwaste]. Problemy Chornobyl’skoi zony vidchuzhennia [Problems of Chornobyl exclusion zone], vol. 20, pp. 13−26. (in Russ.)
17. Maksymenko А. М., Bondarkov M. D., Oskolkov B. Ya., Seida V. A., Dubas V. N. (2019). [Results for Studies of Hard-toMeasure Radionuclides in the Metal of Chornobyl Nuclear Power Plant Equipment being Dismantled, and Estimation of Scaling Factor]. Yaderna Energetyka ta Dovkillia [Nuclear Power and the Environment], vol. 13, no. 1, pp. 67−75. (in Russ.)
18. ISO 11929 Determination of the Characteristic Limits (Decision Threshold, Detection Limit and Limits of the Confidence Interval) for Measurements of Ionizing Radiation–Fundamentals and Application. Geneva, Switzerland: International Standard Organization, 2019.
If the article is accepted for publication in the journal «Industrial Heat Engineering» the author must sign an agreement on transfer of copyright. The agreement is sent to the postal (original) or e-mail address (scanned copy) of the journal editions.
Authors retain copyright and grant the journal right of first publication with the work simultaneously licensed under a Creative Commons Attribution License International CC-BY that allows others to share the work with an acknowledgement of the work’s authorship and initial publication in this journal.