Plus the presurized helium inside and what ever attachments there are on the tube to allow it to fit into one of the four assemblies. Or are you saying that the core of a reactor consists of more than four assemblies, each containing ~25 tubes filled with pellets. I really don't know how schematic the diagrams are.

"It is not necessary to have hope in order to persevere."

No, an assembly consists of 100-odd zirconium rods or canisters containing the fuel pellets.

The assembly is designed to be grabbed by a crane.

So, in what may be my last act of "advising", I'll advise you to cut the jargon. -- My old PhD advisor, to me, 26/2/11