Abstract: The present disclosure shows an anti-rotation bolt for fastening reactor plates to prevent subsequent SCC problems wherein the bolt head has a circumferential series of anti-rotation tabs extending from the head of the bolt which are moved in by a restrainer cone which is placed on top of the bolt to allow its insertion into the plates and is removed for locking the tabs into detents formed in one of the plates to provide anti-rotation. The cone is again moved over the tabs during the removal of same leaving the bolt undamaged and fit for reuse.