6. Glossary

Minor actinides

Isotopes formed in a reactor by successive neutron capture from fuel nuclei. These isotopes are mainly neptunium ( ²³⁷ Np), americium ( ²⁴¹ Am, ²⁴³ Am) and curium ( ²⁴³ Cm, ²⁴⁴ Cm, ²⁴⁵ Cm).

Assembly

In the core of a water-cooled reactor, the fuel rods are grouped together in bundles, a structure comprising 264 rods (in the case of French PWRs) and loaded as a single unit into the reactor.

Cigéo

Industrial geological storage center

Nuclear fuel