Patents Assigned to Holtec International
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Patent number: 7293602Abstract: A fin and tube assembly for use in a heat exchanger comprising a carbon steel tube, a carbon steel fin, and an external brazing compound comprising a material selected from the group consisting of nickel, chrome, copper, aluminum, zinc, and graphite brazed to the tube and fin is disclosed. A method for making the assembly and a power plant which includes the assembly are also disclosed. The brazing compound functions to prevent corrosion of the carbon steel and also functions to attach the tube and fin together.Type: GrantFiled: June 22, 2005Date of Patent: November 13, 2007Assignee: Holtec International Inc.Inventors: Ranga Nadig, Ram Chandran, Michael Phipps
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Patent number: 7210247Abstract: The present invention provides a method and system for ensuring that cavities used to store radioactive elements are adequately dried without intrusive measuring. In one aspect the invention is a system for drying a cavity loaded with radioactive elements, the loaded cavity having a free volume (VF), a starting vapor pressure (vPS), and a cavity pressure (PC), the system comprising: a non-reactive gas source adapted to supply a non-reactive gas to the system; means to cool a non-reactive gas to a temperature (TC) thereby drying the non-reactive gas; means to flow the dry non-reactive gas to the cavity, the flow means adapted to introduce the dry non-reactive gas to the cavity at a flow rate R for a period of time (t); and means to remove wet non-reactive gas from the cavity; wherein the non-reactive gas source, the cooling means, the flow means, the removal means, and the cavity are fluidly coupled; wherein TC and R are controlled to achieve a desired vapor pressure (vPD) in the cavity in time t.Type: GrantFiled: June 27, 2006Date of Patent: May 1, 2007Assignee: Holtec International, Inc.Inventor: Krishna P. Singh
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Patent number: 7139358Abstract: A system and method for transferring a canister of spent nuclear fuel from a transfer cask to a receiving cask. In one aspect, the system comprises a below grade opening adapted for receiving a cask; a platform positioned within the opening, the platform capable of vertical movement; and at least two jacks for vertically moving the platform; wherein the platform is capable of lowering the cask within the opening. In another aspect, the invention is a method of transferring a canister of spent nuclear fuel to a cask comprising the steps of: lowering a receiving cask having a height into a below grade opening so that a portion of the receiving cask's height is below grade level; and transferring the canister to the receiving cask.Type: GrantFiled: August 10, 2004Date of Patent: November 21, 2006Assignee: Holtec International, Inc.Inventors: Krishna P. Singh, Stephen J. Agace
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Patent number: 7096600Abstract: The present invention provides a method and system for ensuring that cavities used to store radioactive elements are adequately dried without intrusive measuring. In one aspect the invention is a method of drying a cavity loaded with radioactive elements, the loaded cavity having a free volume (VF), a starting vapor pressure (vPS), and a cavity pressure (PC), the method comprising: determining a desired degree of dryness in the cavity in terms of a desired vapor pressure (vPD); cooling a non-reactive gas to a temperature (TC) thereby drying the non-reactive gas; introducing the dry non-reactive gas into the cavity so that the free volume VF of the cavity turns over X times; and removing wet non-reactive gas from the cavity; wherein TC and X are controlled to achieve the desired vapor pressure (vPD) in the cavity. Alternatively, a flow rate (R) can be controlled over time (t) instead of controlling X.Type: GrantFiled: December 13, 2002Date of Patent: August 29, 2006Assignee: Holtec International, Inc.Inventor: Krishna Singh
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Patent number: 7068748Abstract: A system and method for storing spent nuclear fuel below grade that affords adequate ventilation of the spent fuel storage cavity. In one aspect, the invention is a system comprising: a body having a cavity for receiving and storing a spent fuel canister, a major portion of the body positioned below grade; the body having at least one inlet ventilation duct extending from an above grade inlet to a below grade outlet in the cavity. The inlet ventilation duct can be a en elongated substantially S-shape extending from a side wall of the body to the bottom of the cavity. In another aspect, the invention is a method of storing a spent fuel canister using the system.Type: GrantFiled: March 18, 2004Date of Patent: June 27, 2006Assignee: Holtec International, Inx.Inventor: Krishna Singh
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Patent number: 6957942Abstract: An apparatus and method for transferring spent nuclear fuel within a nuclear power plant. In one aspect, the invention is an apparatus for transferring a cask from a first position to a second position comprising: a first beam having a first proximal end and a first distal end, said first proximal end adapted for pivotal connection to a base; a second beam having a second proximal end and a second distal end, said second proximal end adapted for pivotal connection to said base; a member connecting said first distal end and said second distal end, said member comprising a lifting device adapted to raise and lower said cask; wherein said member, said first pivot beam, and said second pivot beam form a unitary structure; and means to rotate said unitary structure about an axis. In another aspect, the invention is a method of using the apparatus to transfer a cask.Type: GrantFiled: March 4, 2003Date of Patent: October 25, 2005Assignee: Holtec International, IncInventor: Stephen J. Agace
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Patent number: 6853697Abstract: An apparatus, transfer cask, system, and method for defueling a nuclear reactor and transferring spent nuclear fuel from a spent nuclear fuel to a storage cask for long terms storage. In one aspect, the invention is an apparatus for use in transferring a canister of spent nuclear fuel from a transfer cask to a storage cask, the apparatus comprising a radiation absorbing shield surrounding a portion of a hole through which the canister can pass; means for securing the apparatus to the top surface of the storage cask; means for securing the bottom surface of the transfer cask to the apparatus; wherein the transfer cask securing means and the storage cask securing means are positioned on the apparatus so that when the apparatus is secured to both the transfer cask and the storage cask, the cavity of the transfer cask, the hole, and the cavity of the storage cask are substantially aligned; and means for moving the bottom lid in a horizontal direction once the bottom lid is unfastened from the bottom surface.Type: GrantFiled: June 3, 2003Date of Patent: February 8, 2005Assignee: Holtec International, Inc.Inventors: Krishna P. Singh, Stephen J. Agace
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Patent number: 6848223Abstract: An apparatus and method for stabilizing a spent nuclear fuel containment cask so as to prevent tipping under design basis earthquake conditions. In one aspect, the apparatus comprises a lamina and a slid plate in surface contact with the lamina, forming a slidable interface; wherein the slidable interface has a coefficient of friction within a range resulting in an acceptable level of net horizontal displacement of a cask resting on the apparatus under design basis earthquake conditions.Type: GrantFiled: January 30, 2002Date of Patent: February 1, 2005Assignee: Holtec International Inc.Inventors: Krishna P. Singh, A J. Soler
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Patent number: 6793450Abstract: A system and method for transferring a canister of spent nuclear fuel from a transfer cask to a receiving cask. In one aspect, the system comprises a below grade opening adapted for receiving a cask; a platform positioned within the opening, the platform capable of vertical movement; and at least two jacks for vertically moving the platform; wherein the platform is capable of lowering the cask within the opening.Type: GrantFiled: February 5, 2002Date of Patent: September 21, 2004Assignee: Holtec International, Inc.Inventors: Krishna P. Singh, Stephen J. Agace
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Patent number: 6718000Abstract: An apparatus, system, and method of storing and transferring a canister of spent nuclear fuel. In one aspect, the apparatus is a lid for a ventilated vertical overpack having a chamber for receiving spent nuclear fuel, the lid having ventilation ducts. In one aspect, the system comprises: a lid for a ventilated vertical overpack having a chamber for receiving spent nuclear fuel, the lid having ventilation ducts; and a ventilated vertical overpack having a cylindrical body including lower ventilation ducts, a bottom, and a chamber formed by the body and the bottom adapted for receiving a canister of spent nuclear fuel.Type: GrantFiled: February 6, 2002Date of Patent: April 6, 2004Assignee: Holtec International, Inc.Inventors: Krishna P. Singh, Stephen Agace
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Patent number: 6625246Abstract: An apparatus, transfer cask, system, and method for defueling a nuclear reactor and transferring spent nuclear fuel from a spent nuclear fuel pool to a storage cask for long terms storage. In one aspect, the invention is an apparatus for use in transferring a canister of spent nuclear fuel from a transfer cask to a storage cask, the apparatus comprising a radiation absorbing shield surrounding a portion of a hole through which the canister can pass; means for securing the apparatus to the top surface of the storage cask; means for securing the bottom surface of the transfer cask to the apparatus; wherein the transfer cask securing means and the storage cask securing means are positioned on the apparatus so that when the apparatus is secured to both the transfer cask and the storage cask.Type: GrantFiled: April 12, 2002Date of Patent: September 23, 2003Assignee: Holtec International, Inc.Inventors: Krishna P. Singh, Stephen J. Agace
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Patent number: 6619042Abstract: A power plant apparatus comprising a condenser for condensing turbine exhaust steam having a steam dome, a steam inlet, a tube bundle, a hot well for collecting condensate, an air removal section, an internal makeup water heater bundle. An internal makeup water header which includes a pipe having spray nozzles arranged counter-current to the flow of steam introduced by the steam inlet is used to introduce heated makeup water into the exhaust stream from the turbine within the condenser.Type: GrantFiled: October 1, 2001Date of Patent: September 16, 2003Assignee: Holtec International, Inc.Inventor: Ranga Nadig
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Patent number: 6587536Abstract: An apparatus and method for maximizing the radiation shielding for spent nuclear fuel during cask transfer procedures. In one aspect, the method comprises submersing an apparatus having a jacket and a cavity for receiving spent nuclear fuel into a pool, wherein the jacket is empty and hermetically sealed; placing spent nuclear fuel into the cavity of the apparatus; lifting the apparatus from the pool; placing the apparatus in a staging area; filling the jacket with neutron absorbing liquid; draining the pool water from the cavity; and lifting the apparatus from the staging area.Type: GrantFiled: March 18, 2002Date of Patent: July 1, 2003Assignee: Holtec International, Inc.Inventors: Krishna P. Singh, Stephen J. Agace
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Patent number: 6519307Abstract: A ventilated overpack apparatus for containing a spent nuclear fuel canister has photon radiation scattering attenuators in the air ducts, preferably at or near the external openings. The apparatus preferably has straight ambient air inlet ducts and straight hot air outlet ducts which allow for improved rates of air flow and, because of the radiation scattering attenuators, far more efficient trapping of photons and reduced dose rates versus prior curvilinear or serpentine duct designs. The method of storing spent nuclear fuel comprises inserting a canister in the ventilated overpack apparatus which has the photon radiation scattering attenuators in the ducts. Preferably the top ducts are formed by three-sided channels in the sidewalls of the overpack and a fourth side formed by the flat bottom of the top lid, and the bottom ducts are also formed by three sided channels with the fourth side being formed in part by the bottom lid and in part by a concrete pad on which the overpack rests.Type: GrantFiled: May 30, 2000Date of Patent: February 11, 2003Assignee: Holtec InternationalInventors: Krishna P. Singh, Everett L. Redmond, II, John C. Wagner, Stephen J. Agace
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Patent number: 6481208Abstract: A system and method for reducing the damaging effects of bypass steam in a cylindrical steam surface condenser in a steam turbine/bypass power plant application consisting of a hat-like steam admission chamber located external to the condenser shell having a header with orifices and dummy rods or tubes arranged between the bypass header and the condensing tubes.Type: GrantFiled: October 1, 2001Date of Patent: November 19, 2002Assignee: Holtec InternationalInventor: Ranga Nadig