Needed a trophy for a nuclear power plant-related event, so I designed one based on a BWR reactor pressure vessel. Note that this is not an exact model - it's more art than engineering.
CAD files are available from Onshape here.
Print the following and assemble with the adhesive of your choice. Tap the hole in the bottom of the vessel for 1/2-13 and attach it to the base with a 1/2-13 x 1.5L bolt.
1 vessel.stl
1 head.stl
1 base.stl
1 skirt.stl
4 ms-part.stl
3 ECCS-part.stl
3 nozzle.stl
18 fw-part.stl