en.Wedoany.com Reported - On August 4, Oak Ridge National Laboratory disclosed that a new solvent extraction process for californium-252 production has completed full-scale testing in the 2025 production campaign. The process reduces the processing time of the key radiochemical separation step by about one week—halving it—while maintaining product quality, and is planned for use in the next production batch.

Californium-252 is a neutron-emitting radioactive isotope. Oak Ridge National Laboratory first irradiates curium targets in the High Flux Isotope Reactor, then transfers the irradiated targets into shielded hot cells at the Radiochemical Engineering Development Center, where multiple chemical steps are used to separate and purify the californium isotope. The laboratory currently organizes a californium-252 production campaign every two years.

The traditional process uses bis(2-ethylhexyl) phosphoric acid to extract trivalent actinides and lanthanides. Before extraction, the acidity of the target dissolution solution must be significantly reduced, and the acidity adjustment alone takes about one week. The new process instead uses a neutral extractant molecule that can capture accompanying elements directly in high-acidity solutions, eliminating this processing step.

In the full-scale test, a single extraction cycle removed approximately 95% of accompanying components such as americium, curium, and cerium from the californium-252 solution, with separation performance comparable to the original process. The reduction in processing cycles also shortens the occupancy time of the costly shielded hot cells, leaving room for increased throughput in subsequent production batches.

This process has been under validation since 2015. Researchers initially conducted glovebox experiments using small amounts of production waste solution, then adjusted ligand concentrations using actual target dissolution solution in the 2017 and 2019 production campaigns. In 2023, the test scale was expanded to 6% of that campaign's material; the 2025 full-scale trial completed the transition from laboratory method to production process validation.

Oak Ridge National Laboratory maintains the californium-252 production cycle at once every two years, with output increases primarily achieved by adding irradiation cycles for curium targets in the High Flux Isotope Reactor and improving downstream radiochemical processing efficiency. After further optimization of the new process, it will be used in the 2027 production campaign. Californium-252 can be used for nuclear reactor startup, new fuel testing, oil well logging, coal analysis, instrument calibration, and port security systems.