An improved anode, cup and conductor assembly for a reactor vessel includes an anode assembly supported within a cup which holds a supply of process fluid. The anode assembly has an anode shield carrying an anode, the anode shield having upwardly extending brackets with radially extending members. A diffusion plate is supported above the anode by the anode brackets using first bayonet connections. The anode shield and the anode are supported from below by a delivery tube which also serves to deliver process fluid to the cup. A second bayonet connection is provided between a top portion of the delivery tube and the anode assembly. The conductor is connected to the anode with a plug-in connection which is completed when the tube is coupled to the anode by the second bayonet connection. The diffusion plate and the anode assembly are installable and removable from a top side of the reactor vessel using a tool which is lockable to the diffusion plate or to the anode. The tool provides a handle for manual engagement or disengagement of the first and second bayonet connections.