PhD Defense | Pieter Troosters | Development of new ligands for the selective separation of americium

Development of new ligands for the selective separation of americium

Nuclear energy is a greener alternative to fossil fuel based energy. However, the generation of nuclear waste remains a major drawback. This waste is highly radiotoxic and generates a lot of heat, making it hazardous over very long timescales (hundreds of thousands of years). Consequently, deep geological disposal is considered the safest option to minimize long-term environmental impact. Reprocessing of highly active nuclear waste, however, offers an effective strategy to reduce its volume, long-term radiotoxicity, heat generation, and required storage time, thereby also lowering the cost of disposal facilities. The long-term radiotoxicity and heat load of spent nuclear fuel are primarily governed by the actinides plutonium and americium. While an industrial process already exists for the separation of plutonium, the selective separation of americium remains significantly more challenging. Although numerous extractants and separation systems have been investigated, no scalable industrial process for americium separation has yet been established. If americium can be efficiently separated, it can be fabricated into transmutation targets and subsequently “burned” in fast neutron reactors.

The current leading process for selective americium separation in Europe is the AmSel process. However, the ligand used in this process contains sulfur and is therefore not compliant with the CHON principle. This principle requires ligands to consist exclusively of carbon, hydrogen, oxygen, and nitrogen to avoid contamination of transmutation targets and the generation of secondary waste streams. In this work, hydrophilic CHON-compliant ligands were synthesized and tested in solvent extraction experiments for the selective separation of americium.

Promoters:

Prof. Dr. Wim Dehaen (KU Leuven)
Prof. Dr. Thomas Cardinaels (KU Leuven)

SCK CEN mentors:

Dr. Karen Van Hecke
Dr. Tomas Opsomer