Problematic Issues Regarding the Quantity and Properties of Vitrified High-Level Waste Returning to Ukraine

Keywords

vitrified high-level waste, dose coefficient, crystallization

How to Cite

Olkhovyk, Y. (2019). Problematic Issues Regarding the Quantity and Properties of Vitrified High-Level Waste Returning to Ukraine. Nuclear and Radiation Safety, (2(82), 26-29. https://doi.org/10.32918/nrs.2019.2(82).05

Abstract

Safety justification of long-term storage and further disposal of vitrified high-level waste returning to Ukraine shall be based on reliable information about their physical and chemical characteristics, which include not only the radionuclide composition, but also the estimated evolution of Na-Al-P glass properties in the conditions of potential longterm effect of unfavorable factors. The paper indicates an inconsistency of dose coefficients, which according to the Energoatom standards shall be used to calculate the amount of high-level waste returning to Ukraine after storage and processing of VVER-440 spent nuclear fuel, with the regulatory requirements of the country supplying vitrified high-level waste. The quantitative assessment of transuranium radionuclides and technetium 99 entering the glass matrix also requires a critical review. The research considered the possibility of uncertainty related to the structural homogeneity of a glass matrix due to the underestimation of cracking and crystallization processes that occur in the package in sodium-aluminophosphate glass cooling. The presence of a large number of rare-earth oxides in sodium-aluminophosphate glass contributes to its crystallization in slow cooling with monazite formation. These phenomena can lead to a partial conversion of amorphous glass into a crystalline phase accompanied by 1-2 order increase in the velocity of leaching of elements. When developing technical requirements for vitrified high-level waste returning to Ukraine, it is necessary to insist on the provision of experimentally determined parameters of the structural homogeneity of glass blocks. There is a need for obtaining experimentally defined parameters of radiation resistance of a sodium-aluminophosphate matrix under the influence of a dose that can be accumulated over a period of 100 years using accelerated self-radiation methods.

https://doi.org/10.32918/nrs.2019.2(82).05

References

1. Analysis of the organization and efficiency of activities on compliance with current international obligations of the Russian Federation related to import, storage and processing of irradiated nuclear fuel of foreign nuclear reactors. Prepared by the Government of the Russian Federation in pursuance of Order of the President of the Russian Federation No. Pr-251 dated 14 February 2002. Retrieved from: http://nuclearno.ru/text.asp?3317

2. Method of calculating quantity of high-level waste returned to Ukraine after technological storage and processing of VVER-440 SFA. SOU-N YaEK 1.027:2010, Kyiv, Ministry of Fuel and Energy, 2010, 61 p.

3. Cabinet of Ministers of Ukraine. Order No. 331-r of 16 May 2018 “On the allocation of funds to the Ministry of Ecology and Natural Resources in 2018”. Retrieved from: https://www.kmu.gov.ua/en/npas/pro-vidilennya-u-2018-roci-kosh

4. International basic safety standards for protection against ionizing radiations and for the safety of radiation sources. IAEA Safety Series No. 115, 2003.

5. Radiation protection and safety of radiation sources. International Basic Safety Standards. General Safety Requirements. International Atomic Energy Agency. Vienna, 2014.

6. State health and safety standards, radiation safety standards of Ukraine (NRBU-97). Approved by the Resolution of Chief State Medical Doctor of Ukraine No. 62 dated 1 December 1997, Kyiv, 1997, 121 p.

7. Radiation safety standard (NRB-99/2009). Approved by the Resolution of the Chief State Medical Doctor of the Russian Federation No. 47 of 7 July 2009.

8. Kopyrin, A., Karelin, A., Karelin, V. (2006). Nuclear fuel production and radiochemical processing technology. Atomenergoizdat Publishing House, 576.

9. Demin, A., Matyunin, Yu., Polyakov, A. (1993). Localization of platinum group elements and technetium during the liquid HLW solidification with obtaining phosphate and borosilicate materials. Proceedings of the 4th Annual Scientific and Technical Conference of the Nuclear Community, VNIINM.

10. Olkhovyk, Yu. (2014). Balance assessment of vitrified high- level waste formation during the reprocessing of Rivne NPP VVER- 440 SNF. Nuclear Energy and Environment, 1(3), 24—27.

11. Crum, J., Vienna, J. (2008). Environmental issues and waste management technologies in the materials and nuclear industries XII. Ceram. Trans., V. 207, 3—8.

12. Stefanovsky, S., Stefanovskaya, O., Semenova, D. (2018). Phase composition and structure of glassy materials on sodium aluminophosphate basis containing rare earth oxides. Radioactive Waste, 1(2), 97-101.