For the destruction of nitric acid in radioactive waste solutions from the reprocessing of nuclear fuel, a batch process has been developed using formic acid as a reducing agent. The main reaction products are N2O and CO2, which can be discharged into the environment. The process has been tested on a lab scale with simulated and real waste solutions as well as on a pilot scale with simulated solutions. Nitric acid turnovers between 80 and 90% are obtained. The final nitrate concentrations in high- and medium-level waste solutions are below 0.5 and 0.2 mol.ℓ−1, respectively. The induction period that occurs when starting the reaction can be described by a reaction rate equation. For our special conditions it lies within the range of a few seconds. The loss of solid particles and formic acid into the off-gas during the whole process amounts to a few parts per million. Corrosion tests under realistic conditions have shown that Incoloy 825 is an appropriate material for the denitration vessel.