EXPERIENCE GAINED FROM THE FRENCH NUCLEAR MATERIAL CONTROL AND ACCOUNTANCY OF NUCLEAR MATERIALS IN SOLID WASTE

French ministerial directive of June 1988 gives the technical conditions for control and accountancy of nuclear materials contained in solid waste. After 13 years of experience, it seems necessary to assess the efficiency of this regulation with regard to the need to know the quality and quantity of nuclear materials in nuclear waste. Before dealing with this experience accumulated during this period of time, it is important to recall the concern with nuclear materials contained in radioactive waste which might be viewed as marginal regarding possible loss, theft or diversion, any events whose French regulation is aimed at preventing from or, if it fails, at detecting. In most facilities, the quantities of nuclear materials discarded in waste are of the same order of magnitude as the material unaccounted for (MUF) which is calculated in the process material balance areas (MBA). That means that an approximate knowledge of the quantities of nuclear materials in waste would significantly affect the significance of the MUF in relevant MBAs and its limits of error and hence would complicate any detection of loss, theft or diversion through material balance analysis. Those considerations also apply to nuclear material qualities as well (uranium enrichment for instance) and show that an efficient follow-up of waste is mandatory if we keep in mind the objectives of the French safeguards regulation. For the same reason of MUF consolidation, a reliable and precise accountancy of nuclear materials in waste is needed. Domestic safeguards inspections with physical measurements for nuclear materials contained in waste have put into evidence some limitations in terms of quantity and quality measured. Indeed, the Radioactive Material Security Department (DSMR) of the Institute for Protection and Nuclear Safety (IPSN) has developed, for inspections purposes, original and complementary methods for the measurement of plutonium in waste drums. This paper describes the principle of these devices and the conclusion that can be drawn on the experience feedback obtained over the last years.