Apparatus for controlling molten core debris
AssigneeThe United States of America as represented by the United States Energy Research and Development Administration
InventorsMartin P. Golden, Roger W. Tilbrook, Neal F. Heylmun
Life of this patent
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Abstract
Apparatus for containing, cooling, diluting, dispersing and maintaining subcritical the molten core debris assumed to melt through the bottom of a nuclear reactor pressure vessel in the unlikely event of a core meltdown. The apparatus is basically a sacrificial bed system which includes an inverted conical funnel, a core debris receptacle including a spherical dome, a spherically layered bed of primarily magnesia bricks, a cooling system of zig-zag piping in graphite blocks about and below the bed and a cylindrical liner surrounding the graphite blocks including a steel shell surrounded by firebrick. Tantalum absorber rods are used in the receptacle and bed.
Claims9
Apparatus for controlling molten debris from meltdown of a nuclear reactor core, said core being contained in a reactor vessel and including nuclear fuel, said vessel also containing a circulating liquid coolant, wherein said debris melts through the bottom of said reactor vessel causing said debris and said coolant to fall, said apparatus disposed below said vessel and comprising:
- a. at least one debris receptacle comprising:
- i. at least one generally spherical upwardly convex dome comprised of dome blocks which blocks are comprised of a high melting point material and at least some of which blocks have neutron poison rods therein;
- ii. a plurality of bricks positioned radially about said dome comprised of a high melting point material, at least some of said bricks having neutron poison rods therein which extend above said bricks;
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- iii. a layer of pellets positioned above said bricks and about at least a portion of the rods of said bricks, said pellets comprised of a material having a density at least equivalent to that of said molten fuel and being miscible with said molten fuel;
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- b. means disposed below and radially about said bricks and pellets for supporting and controlling said dome, bricks and pellets.
Apparatus for controlling molten debris from meltdown of a nuclear reactor core, said core being contained in a reactor vessel, wherein said debris melts through the bottom of said reactor vessel, said apparatus comprising:
- a. at least one core debris receptacle, said receptacle comprising:
- i. at least one generally spherical dome piece, said dome piece comprising first alumina dome blocks, said dome blocks including holes, first neutron poison rods of tantalum positioned in said holes, said dome piece containing therein second inner blocks of alumina, said inner blocks comprising tantalum neutron poison;
- ii. at least one layer of alumina dome outer bricks surrounding said dome piece, said outer bricks containing second neutron poison rods of tantalum extending above said bricks;
- iii. uranium oxide pellets above said outer bricks and about at least a portion of said second neutron poison rods;
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- iv. a continuous, generally cylindrical steel receptacle shell about the periphery of said outer bricks and said second poison rods;
- b. a bed surrounding at least the radial periphery and bottom of said core debris receptacle, said bed comprising:
- i. generally inverted spherically arched layers of bed bricks, said bed bricks comprising an inner section of alumina (Al.sub.2 O.sub.3) and an outer section of magnesia (MgO);
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- ii. a layer of magnesia powder about the periphery of said bed bricks;
- c. a liner surrounding the radial periphery and bottom of said bed, said liner comprising:
- i a generally cylindrical steel shell with an open top and continuous bottom;
- ii. insulating silica-alumina firebrick surrounding the periphery and bottom of said shell;
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- iii. means for venting any pressure buildup about said liner;
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- d. means to cool at least one of said bed and said liner, said means comprising:
- i. floor and wall piping positioned about and below said bed;
- ii. graphite cooling blocks enclosing at least a portion of said piping;
- iii. a liquid coolant, said coolant comprising at least one of sodium and potassium;
- iv. a heat removal sink external to said apparatus, said sink comprising a heat exchanger and being in fluid communication with said piping;
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- v. means for circulating said liquid coolant through said piping and said heat exchanger.
Dependencies are inferred from the claim text.