[en] Secondary cold traps treatment is part of the general cleanup and dismantling of the fast breeder reactor Superphenix (Creys-Malville - France) which was shut down in 1997. The purpose of the treatment is to remove sodium hydride and sodium oxide from the inside wire mesh which was used as a filter. Neutralization is accomplished by using slow and gradual chemical process. Fifteen cold traps must be removed from secondary loops of the reactor. These components can be sorted in two categories: six small cold traps which contain approximately 100 g of sodium hydride, 5 kg of sodium oxide and 3 kg of residual sodium; and nine large cold traps which contain approximately from 15 to 200 kg of sodium hydride, from 80 to 300 kg of sodium oxide and 70 kg of residual sodium. Four small cold traps and four large cold traps are contaminated in tritium, some of them highly. A cold trap treatment process has been studied and is under development. It can be divided in four phases: Hot treatment phase (thermolysis): vessel is maintained at high temperature while a constant flow rate of dry hot nitrogen passes through the cold trap. During this phase, sodium hydride is dissociated in hydrogen (tritiated, if the cold trap contains tritium) and sodium. Hot water vapour nitrogen: cold trap is heated while a constant flow rate of wet nitrogen is maintained in the cold trap, in order to neutralize sodium oxide, sodium and possible residual sodium hydride. After cooling, caustic soda is dissolved by water, during different phases. The treatment is finished by drying cold trap vessel using dry nitrogen. The aim of the process is to achieve all the treatment inside the cold trap vessel, without creating any other waste. Hydrogen rate in process gas exhaust will be maintained at low level during all the phases. A gradual experimental validation program of this process has been established. Controlled dissociation of sodium hydride using thermolysis will be first started with a small quantity of product, using an experimental vessel. The six small cold traps from SPX will be used for a pilot scheme of the complete process. An experimental device will be built in order to perform trials. At the end of each trial of a new process phase, analysis and inspections will be performed. The first treated cold trap will be dismantled at the end of cooling phase in order to perform analysis of the final products. Then, a final device will be built to treat secondary large cold traps. (author)