Russia: Results and Prospects of Liquid Solidification Experiments at ROSATOM Sites

Ongoing experimental work has been underway at selected nuclear sites in the Russian State Atomic Energy Corporation (ROSATOM) during the past two years to determine the effectiveness, reliability, application and acceptability of high technology polymers for liquid radioactive waste solidification. The long term project is funded by the U.S. Department of Energy’s Initiatives for Proliferation Prevention (IPP) program. IPP was established in 1994 as a non-proliferation program of DOE / National Nuclear Security Administration and receives its funding each year through Congressional appropriation. The objectives of IPP are: • To engage former Soviet nuclear weapons scientists, engineers and technicians, currently or formerly involved with weapons of mass destruction, in peaceful and sustainable commercial activities. • To identify non-military, commercial applications for former Soviet institute technologies through cooperative projects among former Soviet weapons scientists, U.S. national laboratories and U.S. industry. • To create new technology sources and to provide business opportunities for U.S. companies, while offering commercial opportunities and meaningful employment for former weapons scientists. Argonne National Laboratory provides management oversight for this project. More than 60 former weapons scientists are engaged in this project. With the project moving toward its conclusion in 2012, the emphasis is now on expanding the experimental work to include the sub-sites of Seversk (SCC), Zheleznogorsk (MCC) located in Siberia and Gatchyna (KRI) and applying the polymer technology to actual problematic waste streams as well as to evaluate the prospects for new applications, beyond their current use in the nuclear waste treatment field. Work to date includes over the solidification of over 80 waste streams for the purpose of evaluating all aspects of the polymer’s effectiveness with LLW and ILW complex waste. Waste stream compositions include oil, aqueous, acidic and basic solutions with heavy metals, oil sludge, spent extractants, decontamination solutions, salt sludge, TBP and other complex waste streams. Extensive irradiation evaluation (up to 270 million rad), stability and leach studies, evaporation and absorption capacity tests and gas generation experimentation on tri-butyl phosphate (TBP) waste have been examined. The extensive evaluation of the polymer technology by the lead group, V.G. Khlopin Radium Institute, has resulted in significant discussion about its possible use within the ROSATOM network. At present the focus of work is with its application to legacy LLW and ILW waste streams that exist in a variety of sectors that include power plants, research institutes, weapons sites, submarine decommissioning and many others. As is the case in most countries, new waste treatment technologies first must be verified by the waste generator, and secondly, approved for use by the government regulators responsible for final storage. The polymer technology is the first foreign sorbent product to enter Russia for radioactive waste treatment so it must receive ROSATOM certification by undergoing irradiation, fire / safety and health / safety testing. Experimental work to date has validated the effectiveness of the polymer technology and today the project team is evaluating criteria for final acceptance of the waste form by ROSATOM. The paper will illustrate results of the various experiments that include irradiation of actual solidified samples, gas generation of irradiated samples, chemical stability (cesium leach rate) and thermal stability, oil and aqueous waste stream solidification examples, and volume reduction test data that will determine cost benefits to the waste generator. Throughout the course of this work, it is apparent that the polymer technology is selective in nature; however, it can have broad applicability to problematic waste streams. One such application is the separation and selective recovery of trans-plutonium elements and rare earth elements from standard solutions. Another application is the use of polymers at sites where radioactive liquids are accidently emitted from operations, thus causing the risk of environmental contamination.