Removal of nitric acid from high level liquid wastes (HLLW) of nuclear fuel reprocessing plants is warranted for simplifying the procedure for waste fixing. Chemical denitration aims to reduce the waste volume by destroying the acidity and subsequent concentration by adding suitable reductants. Reduction of nitric acid to gaseous products is an attractive way to accomplish denitration. Nitric acid reduction with formaldehyde proceeds with the formation of CO2, NO2, NO or N2O depending on the reaction conditions and all the reaction products except water can be eliminated from the system in gaseous form. The HNO3–HCHO reaction is governed by a complex mechanism of exhibiting relatively long induction period, depending upon the temperature, concentration of reactants and nitrous acid reaction intermediate. In the present work, a homogeneous denitration process with formaldehyde which offers safety and is governed by controlled kinetics was demonstrated on a laboratory scale. The induction period before commencement of the reaction was eliminated by maintaining the reaction mixture at a pre determined temperature of 98 °C. Based on the results accrued from lab scale experiments, the equipment for pilot plant scale operation was designed, the reaction efficiency for continuous denitration was determined and the investigation of nitric acid destruction was extended to full-scale plant capacity. The role of organics in the waste in foaming up of the reaction mixture was also studied using a synthetic waste solution.