Abrégé

An accelerator-driven subcritical breeding reactor is operated with a neutron multiplication coefficient as large as possible in order to require a small input power from the accelerator, reducing its dimension and hence its cost and complexity. The beam-generated spallation neutron yield then becomes comparable to the fraction of delayed neutrons from the fissioned elements. This can be exploited to ensure an accurate on-line determination of the reactivity. Resulting changes can be adjusted with the help of neutron absorbing control rods and/or variations of the proton current. In addition, the temperature variations during operation can be continuously monitored and adjusted in order to avoid that the subcritical systems approaches too closely the (delayed) criticality condition and that the neutron multiplication coefficient remains within acceptable limits.

Classes IPC  ?

• G21C 1/30 - Réacteurs sous-critiques
• G21C 7/34 - Commande de la réaction nucléaire par utilisation d'une source de neutrons primaire
• G21D 3/10 - Régulation de différents paramètres dans l'installation par une combinaison d'une variable dérivée du flux de neutrons avec d'autres variables de commande, p. ex. dérivées de la température, du flux du réfrigérant, de la pression