Closure studs, closure nuts and spherical washers, with the instrument port bolting, lifting lug pins and support anchor bolts round them. We manufacture to your drawings and specifications.
The closure of a generic pressurised water reactor vessel, drawn from public documents: a shell 159 in. inside diameter, a head flange 188 in. across and 45 closure studs of 7 in. diameter, threaded into the vessel flange and sealed by two concentric metal O-rings. It comes apart in the order of a refuelling outage: the instrument ports are opened, the closure nuts spin off, the nuts and spherical washers are lifted away, the studs are unscrewed and lifted out, and then the head lifts off and the O-rings show. The studs, nuts, washers and smaller bolting are in colour. Press Solid view for a steel model, or Cutaway to see the flange section, the tapped stud holes, the O-ring grooves and the wall of the head and shell.
Forty-five studs of 7 in. diameter, threaded into tapped holes in the vessel flange and passing up through the head flange. Typically SA-540 Grade B23 or B24. Released with hydraulic stud tensioners, then unscrewed and lifted out before the head is lifted.
One on each stud, bearing on the head flange through a spherical washer. Shown as a round slotted nut; the shape follows the vessel drawing.
A two-piece ball-and-socket washer under each nut, which keeps the stud loaded in line while the head flange flexes during bolt-up.
Small studs and nuts on the flanged instrument ports in the head, opened before the head is lifted. Illustrative: many ports use a clamp or quick-release joint instead.
Headed pins coupling the lifting rig to the lugs welded round the edge of the head dome. Illustrative arrangement.
Hold the base plate of each vessel support to the concrete. The vessel rests on a pad under each inlet nozzle and slides on the support as it heats up. Illustrative arrangement; not disturbed at a refuelling.
Large studs, nuts and washers in alloy steel, to your drawing. Send us your drawings and material spec.
Request a quote832-446-3442A generic vessel, not any plant's or maker's design. The shell and flange diameters, head wall and radius, nozzle bores and heights, the number and diameter of the closure studs, the number of head penetrations and the two O-rings follow figures published in public regulator documents. The bolt circle, stud length, nut and washer shapes, flange heights, nozzle forgings, supports, instrument ports and lifting lugs are illustrative, typical proportions, and the bolting materials are typical. Shown to describe the joint only; your drawings and your quality requirements govern. We manufacture to your drawings and specifications.
Drawn from public regulator documents (a design control document and final safety analysis reports) for the vessel size, stud count and diameter, nozzle sizes and seal arrangement; bolting material is named to ASME SA-540 as typical.
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