Roof reflector for a gas-cooled pebble-bed reactor and process for the disassembly of the roof reflector
AssigneeHochtemperatur-Reaktorbau GmbH
InventorsRolf Fritz, Bernhard Kalden, Karl-Friedrich Kissel
Life of this patent
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Abstract
The invention concerns a roof reflector suspended from the thermal cover shield of a gas-cooled pebble-bed reactor with a plurality of passages for absorber rods arranged in a triangular lattice, and with channels for the passage of the cooling gas. The roof reflector comprises a plurality of essentially hexagonal graphite blocks arranged in several layers to form vertical, closely-adjacent columns. A process for the disassembly of the roof reflector is further provided.
Claims11
In a gas-cooled pebble-bed reactor having a thermal cover shield, a roof reflector for suspension from said thermal cover shield, comprising:
- a plurality of graphite blocks of essentially hexagonal cross-section grouped in a plurality of layers superposed such that blocks in adjacent said superposed layers are aligned to form plural adjacent columns;
- a group of three adjacent said columns comprising a supportable unit with three said blocks forming a lowermost layer of said unit, each said block being associated with only one said unit;
- a support block for supporting each said unit, each said support block arranged beneath at least a portion of said blocks forming a lowermost layer of a respective unit to be supported;
- and
- a respective hanger bolt for releasably fastening each said support block to said thermal cover shield,
- each said unit having an opening through which a said hanger bolt passes from a said support block to sad thermal cover shield, said blocks forming said lowermost layer of each said unit having lower means for interlocking with a respective said support block and upper means for interlocking with blocks in a said layer superposed on said lowermost layer, and each said unit having a sidewall portion shaped such that a group of three abutting said units defines a passage for receiving an absorber rod, each said unit being associated with only one said passage.
In a gas-cooled pebble-bed reactor contained in a pressure vessel and having a thermal cover shield, said pressure vessel and said thermal cover shield provided with a plurality of spaced-apart tube passages for the insertion and removal of absorber rods, said reactor including a roof reflector comprising a plurality of graphite blocks of essentially hexagonal cross-section grouped in a plurality of layers, and said roof reflector having a plurality of openings for receiving respective absorber rods, and said blocks in adjacent said superposed layers are aligned to form plural adjacent columns, a group of three adjacent said columns comprising a supportable unit, with three said blocks forming a lowermost layer of said unit, a support block supporting each said unit releasably fastened to said thermal cover shield by a respective hanger bolt, the process comprising removing a said absorber rod from said roof reflector through an associated said tube passage;
- lifting said blocks of a said unit adjacent said associated tube passage one layer at a time, and removing said blocks through said associated absorber rod tube passage;
- releasing said support block from said thermal cover shield;
- and removing said support block through said associated tube passage.
Dependencies are inferred from the claim text.