Patents Assigned to MPR Associates, Inc.
  • Publication number: 20200055106
    Abstract: Method for mitigating stress corrosion cracking at an internal (i.e., wetted-side) weld area in piping of a nuclear power plant includes the steps of actuating a radially movable tool to produce a radial bad against the internal (i.e., normally wetted) surfaces at or near the weld area to create a deep residual compressive stress state at the wetted surface of the weld. The method permits post-process verification by physical measurements of surface distortion.
    Type: Application
    Filed: May 16, 2019
    Publication date: February 20, 2020
    Applicant: MPR Associates, Inc.
    Inventors: James E Nestell, David W. Rackiewicz, Alan C Kepple
  • Patent number: 7505546
    Abstract: A method of preventing separation of a feedwater sparger end bracket assembly comprises installing first and second clamp members of a clamp over a feedwater sparger end bracket assembly in opposition to one another, and leaving the clamp in place to constrain the feedwater sparger end bracket assembly against separation in first, second and third directions.
    Type: Grant
    Filed: March 22, 2006
    Date of Patent: March 17, 2009
    Assignee: MPR Associates, Inc.
    Inventors: Patrick J. Butler, H. William McCurdy
  • Patent number: 7492851
    Abstract: A constrained feedwater sparger end bracket assembly comprises a boiling water reactor vessel, a feedwater sparger including a conduit within the vessel, a feedwater sparger end bracket assembly connected to an end of the conduit at a sparger/bracket junction, and a clamp secured on the feedwater sparger end bracket assembly. The clamp constrains the feedwater sparger end bracket assembly in directions horizontal, vertical and radial to the vessel.
    Type: Grant
    Filed: March 22, 2006
    Date of Patent: February 17, 2009
    Assignee: MPR Associates, Inc.
    Inventors: Patrick J. Butler, H. William McCurdy
  • Patent number: 7185798
    Abstract: An apparatus and method for mechanically reinforcing the weld between a riser pipe and riser brace of a jet pump assembly are characterized by first and second attachment members for attachment on a riser brace of the jet pump assembly, and first and second clamp bodies respectively pivotally mounted on the attachment members for movement to a clamping position. In the clamping position, respective abutment surfaces of the clamp bodies are forced against a riser pipe that is attached to a yoke of the riser brace. The abutment surfaces apply radial forces to the riser pipe, and the radial forces are reacted by forces applied against the yoke by respective engagement elements of the attachment members whereby the riser pipe and riser brace are clamped together between the abutment surfaces and the engagement elements.
    Type: Grant
    Filed: April 22, 2004
    Date of Patent: March 6, 2007
    Assignee: MPR Associates, Inc.
    Inventor: Patrick J. Butler
  • Patent number: 6535827
    Abstract: Rupture path logic methods of detecting, locating and isolating ruptures within a fluid piping system are disclosed, wherein a rupture within a piping system can be detected and isolated based solely upon local pressure and flow rate measurements at individual valves within the system without the need for communication of measured fluid data between valves at various locations throughout the system. A fluid characteristic is determined individually for each valve based upon the pressure and flow rate measurements at the valve, and that fluid characteristic is compared with set point fluid characteristic information to determine whether each valve is on a fluid path between a fluid supply source and a rupture.
    Type: Grant
    Filed: October 30, 2000
    Date of Patent: March 18, 2003
    Assignee: MPR Associates, Inc.
    Inventors: Thomas Lestina, Melissa Bradley, Ryan Downs, Eric Runnerstrom
  • Patent number: 6464424
    Abstract: A method of repairing a crack in a boiling water reactor shroud includes forming a pair of slots in the shroud on opposite sides of the crack in angled relation to one another so that the lateral spacing between the slots increases in a direction parallel to the crack, lowering a wedge clamp with laterally spaced slides into the annular space between the core shroud and the reactor vessel, positioning the slides in the slots, and moving the clamp in the direction of increasing lateral spacing between the slots to an operational position where the clamp prevents unacceptable opening of the crack during reactor operation by providing a structural load path which transmits structural loads across the crack. The slots are preferably configured to mate cooperatively in a manner which prevents the clamp from moving in a radially outward direction relative to the shroud once the clamp has been installed.
    Type: Grant
    Filed: July 13, 2000
    Date of Patent: October 15, 2002
    Assignee: MPR Associates, Inc.
    Inventors: Sterling J. Weems, William E. Sylvester
  • Patent number: 6437344
    Abstract: A product irradiation device includes an enclosure and an irradiator shell disposed in the enclosure. The shell comprises a wall or walls enclosing an irradiation source and a transport channel extending from an inlet port to an outlet port of the shell. The enclosure has an entry opening, communicating with the inlet port, through which products are introduced in succession into the transport channel from external of the enclosure. The enclosure has an exit opening, communicating with the outlet port, through which products discharged in succession from the transport channel are transported to a location external of the enclosure, the exit opening being disposed at a location different from the entry opening. The shell has a non-moving transport surface defined by a surface or surfaces of the wall or walls and upon which the products are advanced in fixed increments through the transport channel past the irradiation source.
    Type: Grant
    Filed: August 25, 1999
    Date of Patent: August 20, 2002
    Assignee: MPR Associates, Inc.
    Inventor: David G. Strawson
  • Patent number: 6371685
    Abstract: A method of repairing a crack in a boiling water reactor shroud includes forming a pair of slots in the shroud on opposite sides of the crack in angled relation to one another so that the lateral spacing between the slots increases in a direction parallel to the crack, lowering a wedge clamp with laterally spaced slides into the annular space between the core shroud and the reactor vessel, positioning the slides in the slots, and moving the clamp in the direction of increasing lateral spacing between the slots to an operational position where the clamp prevents unacceptable opening of the crack during reactor operation by providing a structural load path which transmits structural loads across the crack. The slots are preferably configured to mate cooperatively in a manner which prevents the clamp from moving in a radially outward direction relative to the shroud once the clamp has been installed.
    Type: Grant
    Filed: July 13, 2000
    Date of Patent: April 16, 2002
    Assignee: MPR Associates, Inc.
    Inventors: Sterling J. Weems, William E. Sylvester
  • Patent number: 6264203
    Abstract: A method for repairing cracked jet pump riser assemblies in a boiling water reactor utilizes a spacer clamp and a seal collar. The spacer clamp is secured to the riser assembly to limit horizontal displacement of the riser assembly, and the seal collar is secured around the weld joining the riser elbow and the thermal sleeve to limit leakage from the weld over a predetermined range of horizontal displacement defined by the spacer clamp. A method for repairing a circumferential weld connecting an elbow of a jet pump riser assembly with a thermal sleeve involves positioning the weld within a seal collar and securing the seal collar on the jet pump riser assembly so that seals of the seal collar sealingly contact the elbow and the thermal sleeve, respectively, circumferentially on opposite sides of the weld.
    Type: Grant
    Filed: January 28, 2000
    Date of Patent: July 24, 2001
    Assignee: MPR Associates, Inc.
    Inventors: Sterling J. Weems, William E. Sylvester
  • Patent number: 6195892
    Abstract: A method for replacing cracked core spray supply piping in a boiling water reactor vessel includes removal of all or part of the core spray supply piping inside the reactor vessel and replacement of the piping with new piping components configured to couple with one another or any remaining core spray supply piping without being welded. In accordance with one aspect of the invention, a lower elbow of the core spray supply piping is removed and replaced with an elbow assembly configured to mechanically couple with an existing feed-through assembly at the core shroud, for example by use of friction fit, bias members, and/or bolts. A vertical section of the core spray supply piping feeding into the elbow can also be removed and replaced with a new piping section configured to mechanically couple with the replacement lower elbow assembly, for example using pins, clamps and sealing members such as piston rings.
    Type: Grant
    Filed: May 27, 1999
    Date of Patent: March 6, 2001
    Assignee: MPR Associates, Inc.
    Inventors: Sterling J. Weems, William E. Sylvester
  • Patent number: 6178635
    Abstract: A method of repairing a crack in a boiling water reactor shroud with a clamp having pins eccentrically mounted on disks connected by a structural member includes inserting the pins into openings formed in the shroud on opposite sides of the weld and turning the disks to rotate the pins toward the weld such that edges of the holes are engaged by the pins to transmit loads from the shroud to the structural member rather than the weld. A seal member is mounted in compression between a flange at an inboard end of at least one of the pins and an inner surface of the shroud to control leakage through the opening in the shroud.
    Type: Grant
    Filed: August 10, 1999
    Date of Patent: January 30, 2001
    Assignee: MPR Associates, Inc.
    Inventors: Harold William McCurdy, Jr., Sterling J. Weems, William E. Sylvester
  • Patent number: 6167618
    Abstract: A method of repairing a crack in a boiling water reactor shroud with a clamp having pins eccentrically mounted on disks connected by a structural member includes inserting the pins into openings formed in the shroud on opposite sides of the weld and turning the disks to rotate the pins toward the weld such that edges of the holes are engaged by the pins to transmit loads from the shroud to the structural member rather than the weld. A locking mechanism using set screws can be used to lock the disks in a desired rotational position relative to the clamp.
    Type: Grant
    Filed: March 24, 1999
    Date of Patent: January 2, 2001
    Assignee: MPR Associates, Inc.
    Inventors: Sterling J. Weems, William E. Sylvester
  • Patent number: 6138353
    Abstract: A method of repairing a crack in a boiling water reactor shroud includes forming a pair of slots in the shroud on opposite sides of the crack in angled relation to one another so that the lateral spacing between the slots increases in a direction parallel to the crack, lowering a wedge clamp with laterally spaced slides into the annular space between the core shroud and the reactor vessel, positioning the slides in the slots, and moving the clamp in the direction of increasing lateral spacing between the slots to an operational position where the clamp prevents unacceptable opening of the crack during reactor operation by providing a structural load path which transmits structural loads across the crack. The slots are preferably configured to mate cooperatively in a manner which prevents the clamp from moving in a radially outward direction relative to the shroud once the clamp has been installed.
    Type: Grant
    Filed: January 5, 1999
    Date of Patent: October 31, 2000
    Assignee: MPR Associates, Inc.
    Inventors: Sterling J. Weems, William E. Sylvester
  • Patent number: 5964029
    Abstract: An apparatus for repairing cracked core spray supply piping in a boiling water reactor vessel includes a pair of clamps extending circumferentially around the piping on opposite sides of a crack and a preloading mechanism urging the clamps toward one another to apply and maintain an axially compressive load on the piping tending to close the crack. For vertical sections of core spray supply piping, the clamps are secured at vertically spaced locations with each of the clamps including a first jaw extending circumferentially around a first portion of the piping and including a first opening oriented substantially parallel to a longitudinal axis of the piping and an elongate passage or channel oriented substantially perpendicular to and in communication with the first opening.
    Type: Grant
    Filed: May 29, 1998
    Date of Patent: October 12, 1999
    Assignee: MPR Associates, Inc.
    Inventors: Sterling J. Weems, William E. Sylvester
  • Patent number: 5839192
    Abstract: An apparatus for repairing cracked core spray supply piping in a boiling water reactor vessel includes a pair of clamps extending circumferentially around the piping on opposite sides of a crack and a preloading mechanism urging the clamps toward one another to apply and maintain an axially compressive load on the piping tending to close the crack. For vertical sections of core spray supply piping, the clamps are secured at vertically spaced locations with each of the clamps including a first jaw extending circumferentially around a first portion of the piping and including a first opening oriented substantially parallel to a longitudinal axis of the piping and an elongate passage or channel oriented substantially perpendicular to and in communication with the first opening.
    Type: Grant
    Filed: November 27, 1996
    Date of Patent: November 24, 1998
    Assignee: MPR Associates, Inc.
    Inventors: Sterling J. Weems, William E. Sylvester
  • Patent number: 5828713
    Abstract: A method of replacing a boiling water reactor core shroud includes the steps of removing at least a portion of the existing core shroud from supporting structure in the reactor vessel, lowering a replacement shroud into the reactor vessel, positioning the replacement shroud on the supporting structure such that a bottom portion of the replacement shroud mates cooperatively with the supporting structure to limit lateral movement of the replacement shroud relative to the reactor vessel, and holding the replacement shroud assembly in place by applying axially compressive forces to the shroud in the direction of the supporting structure. If the existing core shroud is secured by welds, a parting cut is made to remove the shroud and the replacement shroud is held in place by securing a plurality of tie rods between sites on the replacement shroud and the supporting structure at a respective plurality of angularly spaced locations about the shroud periphery.
    Type: Grant
    Filed: October 9, 1997
    Date of Patent: October 27, 1998
    Assignee: MPR Associates, Inc.
    Inventors: William R. Schmidt, Sterling J. Weems
  • Patent number: 5815543
    Abstract: In a nuclear reactor including a reactor vessel and a core shroud disposed within the reactor vessel in laterally spaced relation, a seismic support includes a spacer extending between laterally opposed surfaces of the reactor vessel and the core shroud to limit lateral movement of the core shroud relative to the reactor vessel and a deformable member carried by the spacer and having a configuration to deform substantially elastically in response to impacts caused by an operating basis earthquake and substantially plastically at relatively constant load in response to impacts caused by a design basis earthquake. The deformable member can be carried at an end of the spacer adjacent the reactor vessel or between the spacer and a bearing plate, and can be formed of a material having a yield strength less than that of the spacer and/or be of reduced cross-sectional area as compared with the spacer to yield under a desired seismic load.
    Type: Grant
    Filed: March 25, 1996
    Date of Patent: September 29, 1998
    Assignee: MPR Associates, Inc.
    Inventors: Sterling J. Weems, Thomas E. Greene
  • Patent number: 5809100
    Abstract: In a boiling water reactor having a core shroud disposed within a reactor vessel and a plurality of tie rods installed between vertically spaced sites on the core shroud as part of a core shroud repair, a method of measuring tie rod preload after installation includes the steps of lowering a tool into the reactor vessel from a remote location positioned externally of the reactor vessel, attaching the tool to an upper portion of a tie rod, using the tool to apply a tensile load along a longitudinal axis of the tie rod, measuring the tensile load applied to the tie rod, measuring axial displacement of the tie rod in response to the applied tensile load, plotting the applied load versus the axial displacement measured, and identifying a change in slope on the load-displacement plot occurring at a load corresponding to the tie rod preload.
    Type: Grant
    Filed: June 6, 1997
    Date of Patent: September 15, 1998
    Assignee: MPR Associates, Inc.
    Inventor: Patrick J. Butler
  • Patent number: 5687206
    Abstract: A method of replacing a boiling water reactor core shroud includes the steps of removing at least a portion of the existing core shroud from supporting structure in the reactor vessel, lowering a replacement shroud into the reactor vessel, positioning the replacement shroud on the supporting structure such that a bottom portion of the replacement shroud mates cooperatively with the supporting structure to limit lateral movement of the replacement shroud relative to the reactor vessel, and holding the replacement shroud assembly in place by applying axially compressive forces to the shroud in the direction of the supporting structure. If the existing core shroud is secured by welds, a parting cut is made to remove the shroud and the replacement shroud is held in place by securing a plurality of tie rods between sites on the replacement shroud and the supporting structure at a respective plurality of angularly spaced locations about the shroud periphery.
    Type: Grant
    Filed: October 15, 1996
    Date of Patent: November 11, 1997
    Assignee: MPR Associates, Inc.
    Inventors: William R. Schmidt, Sterling J. Weems
  • Patent number: 5600689
    Abstract: A method and apparatus for repairing nuclear reactor core shrouds includes applying vertical compressive forces to the shroud in situ to urge opposed ends of the shroud toward one another using a plurality of tie-rods, each including a plurality of coaxial longitudinal members separated by a radial gap filled with reactor coolant or some other damping fluid. One of the longitudinal members is secured to upper and lower portions of the shroud for maintaining a sufficient preload to hold the shroud together and is coupled with one or more other longitudinal members in a manner to transmit axial loads thereto upon extending a predetermined axial distance. A plurality of radial spacers can also be positioned at longitudinally spaced locations along the length of the tie-rod to assure control rod insertion by limiting lateral movement of the shroud and can reduce the preload required for preventing the formation of new cracks and stabilizing existing cracks.
    Type: Grant
    Filed: December 15, 1994
    Date of Patent: February 4, 1997
    Assignee: MPR Associates, Inc.
    Inventors: Sterling J. Weems, Noman Cole, H. William McCurdy