The Technology on Irradiated Graphite Fuel Downblending Received the IAEA Positive Expert Conclusion

The technology on irradiated highly enriched uranium (HEU) fuel downblending and immobilization is currently the world’s only unique technology developed by specialists of the National Nuclear Center of the Republic of Kazakhstan.

Recall that in 2010, meeting the international commitments of the Republic of Kazakhstan on nuclear weapon non-proliferation, the National Nuclear Center of the Republic of Kazakhstan in cooperation with Battelle Energy Alliance LLC (USA) initiated a large-scale project on IVG.1M and IGR research reactors conversion to low enriched uranium (LEU) fuel. Operations were carried out as part of the global initiatives for consolidation and elimination of highly enriched uranium accumulated reserves and research reactors conversion to low enriched uranium.

To solve issue on disposition of irradiated graphite fuel of the first core of IGR reactor, that had been stored over 60 years NNC specialists proposed their own conceptual technology on downblending and immobilization. Subsequently, the current technology was approved by specialists from the Idaho National Laboratory, Sellafield Nuclear Complex and IAEA experts. The technology concept included HEU downblending – fuel grinding and mixing with depleted uranium dioxide and its subsequent inclusion into cement matrix while meeting all technological requirements.

R&D work was performed in support of the technology, which confirmed the matrix set criteria, developed rules and standards of the Republic of Kazakhstan, as well as IAEA requirements. Upon R&D results and results of experimental approbation, the technology had been developed for irradiated graphite HEU down blending and immobilization – fuel of the first core of IGR reactor that was submitted to IAEA for expert evaluation.

On February 28, 2023, National Nuclear Center gained conclusion with positive review after consideration of the technology development results by the IAEA leading experts. The expert opinion emphasizes the uniqueness of the technology and its fundamental reliability. Moreover, the IAEA representatives noted that through a well-planned and executed research program in support of design framework for downblended HEU immobilization – IGR fuel, all objectives set were achieved.

Today, it is possible to say that this technology can be used for similar types of fuel in other countries participating in HEU minimization program. This is a significant achievement in the non-proliferation of nuclear weapon.