Abstract: A digital electronic module arrangement includes a module rack carrying a plurality of individual modules which can each be plugged into the rack. A test rack is connected to the module for applying test signals to each module. The module can select either process inputs or test inputs. A testing device provided for individually testing module outputs which respond to a common input. Each module has a rear bus board which has a connector that can be plugged into the module rack, and a forward digital bus board. A window in the front panel allows direct viewing of indicia on a chip corresponding to code within the chip. This code is electronically compared to code in the module software which relates to the module function. A nameplate on the front panel carries the same indicia for ensuring visual verification that the correct function is attributed to the correct module. Electronic verification is also provided by equipment in the test rack.

Abstract: A nuclear reactor and emergency core cooling system. A nuclear reactor is provided with a cylinder around the core barrel that defines an annular channel therebetween. An injection nozzle is provided through the reactor vessel for delivery of emergency coolant to the defined channel. Emergency coolant is supplied during a LOCA to the injection nozzles sequentially from a high pressure tank, a low pressure tank, gravity feed tanks inside the reactor building, and from sumps that collect coolant in the reactor building. Check valves in the upper portion of the cylinder vent steam to the reactor inlet lines during a LOCA. Bores around the upper circumference of the cylinder break any siphoning action that might occur at the injection nozzle if there is a break in the emergency coolant lines from the emergency coolant sources.

Abstract: A nuclear reactor vessel cavity seal plate. An annular support plate is positioned over the cavity between the reactor vessel and the shield structure and seal welded to the shield structure. Inner and outer support rings attached to the annular plate are supported by the existing beams in the annular cavity. A U-shaped flexible annular expansion ring positioned between the annular plate and reactor vessel flange has its inner diameter seal welded to the reactor vessel flange and its outer diameter seal welded to the annular plate. Ports in the annular plate provide access to nuclear instruments below the annular plate. A cover plate is removably attachable to each port to seal the ports. A closable drain is provided in the annular expansion ring. This provides a permanent seal plate that allows flooding of the cavity for refueling with it being necessary to remove only the cover plates for normal reactor operations.

Abstract: A tool for remotely obtaining an impression of a component surface. A support pole is used to position a mold plate having side walls against a component surface. One or more locating guides are provided with seals for sealing off bores in the component surface. A piston from a pneumatic cylinder attached to the support pole is used to force impression material into the space between the mold plate and component surface. An adhesive plate on the mold plate insures removal of the impression with the mold plate once the impression material has hardened. The surface condition of the component may be determined by inspection of the negative impression.

Abstract: A support base has adjustable slides mounted thereon. A cam arm is mounted at one end on a piston rod that is used to cause vertical movement of the cam arm. The opposing end of the cam arm has a bore that rotatably receives a sleeve therein. An electrode holder is pivotally mounted in the sleeve such that one end of the electrode holder extends beyond the end of the sleeve. The electrode holder is movable between a first normal working position and a second non working position that corresponds to movement of the cam arm. A drive motor and belt are engaged with the sleeve to cause rotation of the sleeve, electrode holder, and electrode to perform machining operations on a workpiece that the electrode is inserted into.

Abstract: An apparatus for removing sludge from the tubes and tubesheet of a steam generator. A support structure is adapted to be mounted at an access port of a steam generator. A lance tube extends from the support structure into the steam generator. A spool attached to a high pressure hose is received in the lance tube. A pinch roller assembly mounted on the support structure is used to move the cylinder through the lance tube. High pressure water flows through slots drilled in the spool and out holes in the lance tube against the tubes and tubesheet. A rocker motor causes back and forth rotation or rocking of the lance tube to create a sweeping action. The lance tube may also be adjusted axially to insure that the water streams are directed to the tube lanes.

Abstract: A method for replacing a nozzle in a pressure vessel. The existing nozzle is cut approximately at the inside surface of the pressure vessel wall. The portion of the existing nozzle that extends beyond the exterior of the pressure vessel wall is removed. A weld pad is deposited on the exterior of the pressure vessel wall around the nozzle bore. The remainder of the existing nozzle is removed. A corrosion resistant thermal spray coating is applied to the nozzle bore. A replacement nozzle is installed in the nozzle bore and seal welded to the weld pad on the exterior of the pressure vessel wall.

Abstract: A replacement nozzle and method for replacing a nozzle in a pressure vessel. The original nozzle is removed and a weld preparation is machined into the original weld. The vacated nozzle hole is partially drilled out from the interior of the vessel. A weld land sleeve is received in the drilled out portion of the nozzle hole and a replacement nozzle is received in the weld land sleeve. The sleeve and replacement nozzle are welded in place on the inside of the vessel wall.

Abstract: The spacer pin of this invention is preferably threadably secured to a thermal shield normally found within reactor vessels. It comprises a main body having a cavity therein which houses a locking assembly that alternately engages or disengages the threads of the thermal shield as desired. Ideally, as bolt means are is rotated within the main body, locking keys are either moved into engagement with the threads of the thermal shield or the locking keys are removed from such engagement with the thermal shield. In this fashion, the spacer pin may be locked onto or unlocked from the thermal shield as desired. A locking cap prevents the bolt means from coming unthreaded during use and also insures that the spacer pin remains secured to the thermal shield.

Abstract: A non-intrusive vibration measurement system and method using commercial ultrasonic instruments together with digital signal filtering and analysis techniques is adapted to quantitatively detect vibrations as small as 0.04-inch peak-to-peak. The system and its methodology is used for in-service vibration monitoring of internal components of check valves, pumps, nuclear reactors, steam generators and heat exchangers, especially when the vibration frequency is too low for quantitative analysis by accelerometers and when the strain induced is too low for strain gauge analysis, and when the vibrating component is in an "encased" environment.

Abstract: A nuclear reactor vessel cavity seal plate. An annular support plate is positioned over the cavity between the reactor vessel and the shield structure. The inner diameter of the support plate rests freely upon the reactor vessel flange to allow movement of the vessel thereunder during thermal expansion and contraction. A flexible annular seal positioned over the support plate has its inner diameter seal welded to the reactor vessel flange and its outer diameter seal welded to the shield structure. Matching ports in the support plate and seal provide access to nuclear instruments below the support plate. A mounting block around each port accepts a cover plate that seals the port. This provides a permanent seal plate that allows flooding of the cavity for refueling with it only being necessary to remove the cove plates for normal reactor operations.

Abstract: A method and apparatus for replacing an existing fuel guide pin in an upper core plate of a nuclear fuel assembly. The existing guide pin is removed to the level of the bottom of the core plate and inside the bore in the core plate to a point adjacent the pin retaining nut. A longitudinal bore is then created in the remaining portion of the existing fuel guide pin. A replacement fuel guide pin formed from a pin body, collet lock, and bolt is inserted into the bore in the upper core plate and through the bore in the remaining portion of the existing pin. The bolt and collet lock are inserted into bore at opposite ends of the pin body and threaded together. A tapered shoulder at one end of the collet lock passes through the bore created in the existing guide pin and secures the replacement guide pin to the remaining portion of the existing pin.

Abstract: A device for restricting the motion of a thimble tube in a nuclear reactor during normal reactor operating conditions. A cylindrical sleeve open at each end has upper, middle, and lower sections. The upper section has an over-expanded area adjacent the top end to aid in proper positioning in the lower core support plate. The middle section is formed from inner and outer sections attached at their ends and formed from material having different coefficients of thermal expansion. The inner portion of the middle section moves from a first normal relaxed state during cold conditions in the reactor to a second flexed state during hot conditions in the reactor to provide a clamping action on the thimble tube received by the sleeve. A baffle in the lower section reduces coolant flow velocity and pressure through the sleeve.

Abstract: A replacement nozzle and heater sleeve for a nuclear reactor coolant system pressurizer. The heater, damaged heater sleeve exterior of the pressurizer and a portion of the heater sleeve inside the heater sleeve bore are removed. The heater sleeve bore is partially tapped to provide threads at its lower end. A sleeve having a first seal ring positioned at its upper end is threaded into the heater sleeve bore such that the first seal ring presses against the original heater sleeve and provides a seal. A second seal ring on a flange on the sleeve is pressed into sealing engagement with the exterior of the pressurizer.

Abstract: A tool positioning assembly for use inside a steam generator. A loading tool assembly removably attachable to a support base is used to insert the support base into the steam generator through a manway opening. The support base is removably attached to the steam generator at the manway. A retractable foot assembly pivotally attached to the support base stabilizes the support base inside the steam generator. A track assembly, removably attachable to the support base after removal of the loading tool assembly, receives an arm. A driven cogwheel on the waist of the manipulator engages a rack on the track assembly and support base for selectively driving and positioning the arm thereon. A tool coupling mounted on the arm is adapted to receive remotely controlled tools. The four degree-of-freedom movement of the arm provides access to all tubes in the tubesheet and allows mounting of tools outside the steam generator.

Abstract: This invention pertains to an automated method of testing the spring pack found in motor operated valves. It includes the steps of compressing the spring pack in a test stand while the compressive load applied and the vertical displacement occurring as a result of such loading is measured. This data is sent to a computer that records selected load measurements which correspond to pre-selected displacement values. Afterwards, this data is reported such as by a graph or other report that provides a comparison of the pre-selected displacement values with its respective compressive load.

Abstract: This invention pertains to a method and apparatus for testing the spring pack of a motor operated valve. It incorporates a test stand into which the spring pack is inserted. A horizontal reference plane is attached to the spring pack afterwhich the spring pack is compressed with the vertical displacement of this reference plane being measured. Also measured is the force applied to the spring pack such that afterwards, a comparison of the vertical displacement versus the load applied can be made.

Abstract: A method and apparatus for replacing an existing fuel guide pin in an upper core plate of a nuclear fuel assembly. The existing guide pin is removed to the level of the bottom of the core plate and inside the bore in the core plate to a point adjacent the pin retaining nut. A longitudinal bore is then created in the remaining portion of the existing fuel guide pin. A replacement fuel guide pin formed from a pin body, collet lock, and bolt is inserted into the bore in the upper core plate and through the bore in the remaining portion of the existing pin. The bolt and collet lock are inserted into a bore at opposite ends of the pin body and threaded together. A tapered shoulder at one end of the collet lock passes through the bore created in the existing guide pin and secures the replacement guide pin to the remaining portion of the existing pin.

Abstract: A method and apparatus for replacing a nozzle or heater sleeve in a nuclear reactor coolant system pressurizer. The tubular main body portion of the replacement nozzle is threadably received in the nozzle bore after the original heater and damaged heater sleeve have been removed and the nozzle bore partially tapped to provide a threaded area therein. The first or upper end of the main body portion is positioned substantially flush with the interior of the pressurizer. A seal weld is provided between the upper end of the main body portion and the interior of the pressurizer. A flange that extends radially from and adjacent the second or lower end of the main body portion bears against the exterior of the pressurizer when the main body portion is in its installed position inside the heater sleeve bore.

Abstract: In order to supply emergency coolant directly to the core inlet of a nuclear reactor, a separate and distinct channel is located within the reactor vessel. This channel flows downward along the perimeter of the core barrel and discharges its emergency coolant directly to the core inlet. Separate nozzles couple this channel to the supply of emergency coolant.