Passage through the wall of a reinforced concrete pressure vessel

Claim 1

In a gas cooled high temperature reactor having a reinforced concrete pressure vessel and a passage construction for a conduit through the wall of the reinforced concrete pressure vessel, the improvement comprising: an outer tubular metal liner of a generally cylindrical configuration having a substantially constant diameter in direct contact with the concrete of the reinforced pressure vessel wall and extending through said wall; an inner tubular member comprising a plurality of axially aligned cylindrical members of different diameter forming a generally stepped, elongate cylindrical passage arranged generally coaxially within said outer tubular metal liner along the entire length of said outer tubular metal liner within and through said passage to define therewith an axially stepped annular space; solid radiation shielding material disposed within and substantially filling said stepped annular space; at least two annular ring members rigidly connecting said inner and said outer tubular members; the first of said annular ring members positioned at the inside surface of the pressure vessel and the second of said annular ring members positioned at the outside surface of the pressure vessel; a third annular ring member in the central portion of said passage; and a welded gas-tight connection between said inner and said outer tubular members and each of said first and second annular ring members.