[en] The hydrates of uranium trioxide easy react with halogenides: it is possible to prepare ammonium or pyridinium chloro-uranates at room temperature. With potassium chloride one must use hydrothermal synthesis technique. At 200⁰C one obtains four phases, among them one chloro-uranate Ksub(x)UO₃Clsub(x) and one hydrated uranate 3 K₂O, 16 UO₃, m H₂O. The acidobasic charater of UO₃, in the Bronsted's like in the Lewis's maning in the formation of those compounds is discussed

[en] 'To detect then delay the progression of a potential adversary in order to have time for interception before he reaches his target' is a concept as old as the hills that is sometimes also called 'defense in depth'. While this physical protection principle is simple, the development of such systems sometimes is not. The analyst, who does not want to find out to his cost that his facility is vulnerable, then has to face the tricky problem of assessment. For this reason, CEA developed the EVA method, which allows demonstrating that 'the adversary would actually be intercepted before reaching his target'. With regard to the protection of nuclear materials, in 1995, the regulatory authority notified its approval for application of the EVA method in security surveys for CEA facilities. (author)

[en] CEA's missions in various sectors of activity such as nuclear, defence, industrial contracts and the associated regulatory requirements, make it necessary to develop a strategy in the field of physical protection. In particular, firms having nuclear materials are subject to the July 25, 1980 law no.80-572 on the protection and control of nuclear materials. A holding permit delivered by the regulatory authority is conditioned to the protection by the operator of the nuclear materials used. In France it is the nuclear operator who must demonstrate, in the form of a security study, that potential aggressors would be neutralised before they could escape with the material. To meet these requirements, we have developed methods to assess the vulnerability of our facilities. The EVA method, the French acronym for 'Evaluation de la vulnerabilite des Acces' (access vulnerability system) allows dealing with internal and external threats involving brutal actions. In scenarios relating to external threat, the intruders get past the various barriers of our protection system, attempting to steal a large volume of material in one swoop and then escape. In the case of internal threat, the goal is the same. However, as the intruder usually has access to the material in the scope of his activities, the action begins at the level of the target. Our protection system is based on in-depth defense where the intruders are detected and then delayed in their advance towards their target to allow time for intervention forces to intercept them