Germany-based NUKEM Technologies (a subsidiary of Rosatom) announced that the experimental set-up for its state-of-the-art solidification plant has been completed. NUKEM, an international specialist in radwaste and used fuel management, said this “represents a significant advance in the safe and efficient treatment of radioactive waste generated during the operation and dismantling of nuclear power plants and nuclear facilities”.

NUKEM Technologies is tackling radwaste using in-barrel cementing – a widely used and cost-effective solution to bring different types of radioactive waste into a solid, safe form suitable for long-term storage. The cementation plants developed by NUKEM can treat a wide range of radioactive waste, including high-salt evaporation concentrates, radioactive ash from incineration plants, ion exchange resins, absorber and filter materials, radioactive sludge as well as NORM waste and special waste from oil and gas production plants, refineries and the chemical or medical industry.

For cementing in the barrel, liquid radioactive waste is enclosed in a 200 litre barrel. The end product is an externally non-contaminated steel drum containing immobilised waste in a cement matrix. The system includes:

  • The in-catch mixer;
  • Al necessary drum handling systems such as grippers and roller conveyors;
  • Barrel transfer and sealing / uncapping systems;
  • Dosing system for liquid additives and radioactive liquid waste;
  • Camera system;
  • Filling station for dry material;
  • Tracking system;
  • Radioactivity monitoring;
  • Wipe test;
  • Weighing system for the barrels;and
  • Overflow sensor.

The entire process is designed for automatic operation, which minimises the need for operator intervention. A unique QR code is generated for each barrel, which contains important information about the waste and ensures transparency and traceability throughout the process.

The hot cell in which the mixing processes take place has a high-density, inflatable pneumatic sealing system that prevents leakage during the pumping and dosing processes for liquid waste. The in-barrel mixer, with its four degrees of freedom, ensures a completely homogeneous mixture and excellent product quality in terms of compressive strength and leaching rate for radionuclides in the cement end product.

NUKEM says it attaches great importance to reliability and low maintenance when designing its systems. “The entire system, including the in-barrel mixer, roller conveyors and other components, is remotely controlled from a central control centre. The operating personnel have real-time insight into the ongoing processes and can react quickly to deviations.”

Before the system is used at a nuclear facility, original size mock-ups including machines and equipment are thoroughly tested. “The modular structure and intensive training programme of NUKEM Technologies ensure seamless installation and smooth operation of the cementing system at the customer, which reduces the need for monitoring by the supplier.”

Predecessor company NUKEM Nuklearchemie und Metallurgie GmbH was founded in 1960 and originally focused on processing uranium and the production of fuel elements. The company was recognised for its intensive research & development work. In the 1970s, nuclear engineering and plant engineering were opened up as new business areas. NUKEM Technologies Engineering Services GmbH is a wholly owned subsidiary of NUKEM Technologies GmbH, which has been part of the Rosatom Group since 2009.

Image: The mock-up of the in-barrel cementation facility (courtesy of NUKEM Technologies)