A pressure vessel has a restraint structure for accommodating thermal cycling thereof, including: a body with a cylindrical section; a skirt connected to the body and having a foot; and a plurality of blocks disposed around the skirt adjacent to the foot. Each block is anchored to a support frame or foundation, and has a base and a flange. Each flange overlaps the foot, thereby vertically linking the blocks and the skirt. A radial clearance is formed between an outer surface of the foot and an inner surface of each base. A vertical clearance is formed between an upper surface of the foot and a lower surface of each flange.