CROCUS is a research reactor at École Polytechnique Fédérale de Lausanne, a research institute and university in Lausanne, Switzerland.

The uranium nuclear reactor core is in an aluminium container that measures 130 centimetres (51 in) across with 1.2-centimetre (0.47 in)-thick walls.

The aluminum vessel is filled with demineralized light water to serve as both a neutron moderator and a neutron reflector.

The reactor has six separate safety systems: two cadmium shields and four storage tanks, any of which can shut down the reaction in less than a second.

[2] CROCUS has a license to produce 100 watts (0.13 hp) or a neutron flux of ~2.5 × 109 cm-2s-1 at the core's center.