The purpose of the Seminar was to provide an international interdisciplinary forum for in-depth discussions on the pros and cons of a denitration step by chemical means in the course of solidification of MAW (medium active waste) and HAW (highly active waste), prior to feeding the calciner or melter. In particular, differences In the volatility of some components and aerosol formation during the vitrification step are of interest. Chemical rather than thermal denitration may have particular merits which could simplify off-gas purification. A reduction in the salt burden of waste solutions, leading to a reduction In the volume of solid waste, may also be achieved. The scientific programme of the Seminar consisted of invited lectures only, given by experts actively engaged in this field of research. The emphasis was on extensive discussions among the partiCipants, with the aim of leading to an objective understanding of the state-of-the-art. The meeting also indentified issues and options for future research.

Session 1: Basic Reactions and General Application of Denitration.- - Overview on the application of denitration in the nuclear field.- - Chemical reactions involved in the denitration process with HCOOH and HCHO.- - Alternative organic reductants for denitration.- - Economical aspects of denitration in the management of reprocessing concentrate.- - Safety aspects about denitration.- Session 2: Denitration of Reprocessing Concentrate.- - Denitration of reprocessing concentrates by means of HCHO.- - Denitration of reprocessing concentrate by means of HCOOH.- - Application of denitration/oxalate precipitation in the Petra hot-cell facility.- - Abatement of the NOx evolved during denitration of reprocessing concentrate.- Session 3: Denitration of High Level Liquid Waste.- - Denitration of HLLW for actinide partitioning.- - Operational experience of the denitration of simulated highly active liquid wastes during vitrification.- - Reduction of Ru and Tc volatility during vitrification of HLLW by denitration.- - Industrial application of denitration of HLLW by means of HCHO.- - Conclusions and opinion of the scientific secretaries.- - List of participants.