Session: 05-06: LLW Treatment & Packaging Developments

Paper Number: 119372

119372 - Verification of Radioactive Waste Containers 

Since a new radioactive waste cementation plant has been installed at Paks NPP by the CHEMCOMEX a.s., it became necessary to verify the cemented waste packages (CWP). During the technology, four steel drums containing solid radioactive waste are placed into a reinforced steel container filled with cement paste made from liquid radioactive waste. The cement paste is sampled at the beginning of the waste package preparation, and then the in-line control specimens are prepared to measure compressive strength and diffusion coefficient. These results must represent the cement paste in the container despite the different storage conditions of the specimens and the cemented waste package. While CWPs are stored at ambient temperature, specimens are cured under standard conditions according to EN 12390 (Testing hardened concrete) standards. In order to most accurately estimate the compressive strength of the entire waste preparation process, an extensive comparative compressive strength measurement was performed by Schmidt-hammer based on rebound numbers and core sampling of the containers. It is necessary to predict the 28-day compressive strength at the age of 10 days of the CWPs because the storage capacity of the NPP is finite. Since the technology applies the same mix design with the same type of binder materials and liquid radioactive waste, the compressive strength of the cemented liquid radioactive waste in the container can be predicted.

Thanks to these measurements, the Paks NPP can guarantee on the day of delivery that the waste acceptance criteria for the cement paste are met at the age of 28 days. On the other hand, according to the ALARA (As Low As Reasonable Achievable) principle, these comparative measurements make it possible to reduce the radiation dose from the measurement of large 150 mm (EN 12390) specimens by using smaller 40×40×160 mm (EN 196) ones.

Presenting Author: Attila Baranyi MVM Paks NPP.

Presenting Author Biography: Chief Technologist at MVM Paks NPP in Hungary. He graduated in chemistry (2003) and chemistry teacher (2006) from the University of Veszprém, and then graduated in concrete technology (2021) from Budapest University of Technology and Economics. He previously worked on radioanalysis and the development of liquid radioactive waste treatment technologies: testing of ultrafiltration membranes, and selective sorbents, and developing Advanced Oxidation Processes (AOPs). He currently works in a new testing laboratory related to the radioactive waste cementation technology at the Paks Nuclear Power Plant and developing testing methods and types of equipment.