Abstract: A CEDM data acquisition system (40) receives analog coil-current signals from control element drive mechanism coils (18, 20); conditions the analog signals to remove noise induced therein by the electronic circuitry (44) associated with the control element drive mechanisms; digitizes the conditioned analog signals; displays the acquired test data; and records the data for future use. The inventive data acquisition system preferably has the ability to simultaneously measure, display and record coil-current data for all of the five coils associated with each CEDM rod-group with respect to time. Further, the inventive data acquisition system preferably allows the user to monitor, display and record data for up to eight CEDMs simultaneously. It also allows the measurement of rod-drop times during rod-drop testing of the CEDMs.

Abstract: A robot and associated control system, as well as a method of control, for servicing a heat exchanger having a substantially planar tube sheet which defines a multiplicity of laterally spaced tube openings of known shape, each of which is centered at a coordinate on a tube sheet coordinate system. A sensory system associated with the robot end effector and the associated digital processing system, includes a vision subsystem for generating an image of a portion of the tube sheet and generating a first signal commensurate with the spatial relationship of the tool to a selected tube opening. An optical subsystem is also provided, for projecting a structured light beam toward the tube sheet and receiving a reflected structured light pattern, indicative of how closely the tool is aligned with the target opening.

Abstract: The work cell is divided into a plurality of calibration zones, and calibration is made with only one measured point in each zone. The calibration zones are set up such that the calibration error in each zone remains within an acceptable tolerance. Within each zone, calibration is preferably made according to a linear calibration algorithm. The method according to the invention includes the steps of storing a first database, of the coordinates of all the tube openings in the tube sheet coordinate system. Each coordinate of the first database is assigned to one of a plurality of calibration zones.

Abstract: A method for generating a validated measurement of a process parameter at a point in time by using a plurality of individual sensor inputs from a scan of said sensors at said point in time. The sensor inputs from said scan are stored and a first validation pass is initiated by computing an initial average of all stored sensor inputs. Each sensor input is deviation checked by comparing each input including a preset tolerance against the initial average input. If the first deviation check is unsatisfactory, the sensor which produced the unsatisfactory input is flagged as suspect. It is then determined whether at least two of the inputs have not been flagged as suspect and are therefore considered good inputs. If two or more inputs are good, a second validation pass is initiated by computing a second average of all the good sensor inputs, and deviation checking the good inputs by comparing each good input including a present tolerance against the second average.

Abstract: An omega seal (32) between a housing (24) having a circumferential omega lip (38) including a free end, and a reactor vessel nozzle (22) having a complimentary omega lip (40) including a free end. A semi-rigid, annular seat member (60) is placed within one of the lips, and the housing is positioned in vertical alignment with the nozzle so that the free end of the housing lip and the free end of the nozzle lip are juxtaposed, thereby forming an omega structure having a cavity (44) occupied by the seat member, a gap (42) between the free ends of the lips, and an outer surface (47,49) on either side of the gap. A semi-rigid ring (46) is positioned in conforming relation to the outside surface of the omega structure. A compressive force is applied and maintained on the exterior of the seal ring, thereby extruding a portion of the ring into the gap.

Abstract: A nuclear power plant fuel transfer tube quick operating remote closure device (10) comprised of a reducing ring (20) and a cover assembly (60). The reducing ring (20) is bolted to the transfer tube housing flange (12). Rotation of a chuck key advances jaws on the cover assembly (60) which feed closure latches (78) into a groove (40) on the reducing ring (20). The upper surface (80) of each latch (78) has a bevelled surface (82) corresponding to a bevelled surface (42) of the groove (40). As the latches (78) engage the groove bevelled surface (42), the entire cover assembly (60) is uniformly drawn toward the reducing ring (20). Machined seal faces (13, 30, 44, 68) and O rings (36, 74) provide a fluid and air tight seal between the transfer tube housing flange (12) and the sealing ring (20) and between the cover assembly (60) and the sealing ring (20).

Abstract: A tank (18) forms a chamber having an upper and lower region. The tank (18) is in even elevation with a horizontal pipe (12) having a top region and a bottom region. An upper connecting pipe (14) fluidly connects the top region of the pipe (12) to the upper region of tank (18). A lower connecting pipe (16) fluidly connects the bottom region of pipe (12) to the lower region of the tank (18). Heat junction thermocouples (22) generate a signal indicative of water in the pipe (12). The signal is transmitted to a remote location by line (24).

Abstract: A data acquisition system (1) by which environmental parameters proximate to plant installed valves (2) may be monitored, recorded and correlated with other valve operating data. The system includes sensors (8) for sensing environmental parameters such as gas/vapor concentration, temperature or humidity. The system also includes sensors for sensing changes in the actuating variable (34) and sensors for sensing valve stem displacement (58). The sensors (8, 34, 6) generate electrical signals proportional to the value of the sensed parameter. First data interface equipment (32, 42, 43) is provided for digitizing the sensed actuating variable as the actuating variable is changed to displace the stem, preferably a full stroke from the open-to-close-to-open positions or vice versa. Second data interface equipment (7, 45) is provided for digitizing the sensed environmental parameter as the stem is displaced. Third data interface equipment (6, 45) is provided for digitizing the sensed stem displacement.

Abstract: The manipulator has a base including an elongated bar having a center between first and second opposed ends. Fluidly actuated end effectors at the first and second ends of the base, are extensible for bracing the base against opposed support surfaces on the steam generator, such as locator pins situated within the clamp ring. A rigid arm is connected to the center of the base and extends radially to a free end. A first drive means is provided for remotely rotating the arm around a rotation axis passing through the center perpendicularly to the base. The preferred transducer means include a bracket situated at the free end of the arm, a pair of radially spaced apart mounting posts supported by the bracket and extending in parallel with the rotation axis, and a transducer shoe assembly carried by each post. A transducer element is mounted in each of the shoe assemblies.

Abstract: A method for detecting pH imbalances and/or achieving pH balance in crevices of a pressurized water reactor steam generator. The method comprises obtaining hideout return concentrations of sodium, chloride, calcium and sulfate ions, and silica from the water in the secondary side of the steam generator, the concentrations being expressed as moles per kilogram of water, and determining whether the following conditions exist:eq (anions)<eq (cations), and (a)[Na.sup.+ ]<[Cl.sup.- ]+2[SO.sub.4.sup.2- ] (b)the crevice pH being balanced when all the conditions of the determining step are satisfied. The method of the invention preferably further includes determining whether the following conditions also exist:[Cl.sup.- ]<[Na.sup.+ ] (c)[SiO.sub.2 ]>[Ca.sup.2+ ]+[Mg.sup.2+ ] (d)[Na.sup.+ ]/[Cl.sup.- ]<1.9. (e)If and when the above conditions are met, it can be expected that crevice pH will be balanced at a generally neutral level.

Abstract: The content of and hierarchical access to three levels of display pages containing information on critical function monitoring and success path monitoring.

Abstract: A method for generating an on-line trip signal when a measured one (p1') of a plurality of operating parameters (p1, p2, p3, . . . pN) which define a limit surface on a multidimensional reactor operating space, exceeds a limit value (*p1) on the limit surface. The method includes the steps of storing in an array having at least three dimensions, a set of discrete limit surface values *p1(r) of parameter p1 in ordered triplets, [*p1(r), p2(r) and p3(r)] under reference conditions in which parameters p2 and p3 vary discretely and parameters p4 . . . pN are deemed constant. While operating the reactor, the on-line values p1', p2', p3' of the parameters p1, p2 and p3 are measured. An interpolation is made among the selected triplets to estimate the surface limit value *p1' corresponding to the measured values of p2' and p3'. Preferably, the method includes measuring the operating parameters p4, p5 to obtain values p4' and p5'.

Abstract: The use of alarm indication on the overview (IPSO) display to initiate diagnosis of challenges to critical functions or unavailability of success paths, and further alarm-based guidance toward ultimate diagnosis.

Abstract: Through a localized compact workstation (104), the operator is offered all the monitoring, alarming and control functions which have been previously dispersed over many control panels located throughout the control room (100). The information display hierarchy is composed of an IPSO overview display (122), video display units (108) preferably based on CRT technology and qualified video display units (116) preferably based on solid state flat panel display technology. Associated with each display unit is an individual, independent control module to allow process and component control. One control module (112) supports non-safety control functions and avoids separate controllers for components and process control. Another control module (118) is a qualified system which supports safety system control functions and avoids separate controllers for component and process control.

Abstract: The alarm activation set point and priority for a given, spatially fixed alarm tile can vary depending in part on the mode of plant operation.

Abstract: Alarm acknowledgment can be made not only at the alarm tile array of a given console but via other touch sensitive alarm indications in the screen displays of the monitoring system at the same or other consoles; also, touching one tile can acknowledge multiple alarm sources.

Abstract: An advanced control room complex for a nuclear power plant, including a discrete indicator and alarm system (72) which is nuclear qualified for rapid response to changes in plant parameters and a component control system (64) which together provide a discrete monitoring and control capability at a panel (14-22, 26, 28) in the control room (10). A separate data processing system (70), which need not be nuclear qualified, provides integrated and overview information to the control room and to each panel, through CRTs (84) and a large, overhead integrated process status overview board (24). The discrete indicator and alarm system (72) and the data processing system (70) receive inputs from common plant sensors and validate the sensor outputs to arrive at a representative value of the parameter for use by the operator during both normal and accident conditions, thereby avoiding the need for him to assimilate data from each sensor individually.

Abstract: A non-intrusive method for timing the full operational motion of a valve plug (26) in an electrically actuated, pneumatically operated valve (10). An actuation signal is sent to the valve actuator (54). A coil of wire (68) around the valve actuator solenoid (56), an accelerometer (70) on the solenoid slug (64), or a connection to a permanent pressure sensor (72), non-intrusively senses arrival of the actuation signal at the valve. The time measuring equipment (12) begins timing when the actuation signal is sensed. A laser valve motion sensor (74) then non-intrusively senses when the valve plug reaches a limit of motion. The time measuring equipment ends timing when the valve plug reaches a limit of motion. The time measuring equipment then records the elapsed time from the sensing of the arrival of actuation signal to the final limit of motion of the valve plug.

Abstract: A grid strip (10) for a fuel rod support grid of a nuclear fuel assembly is cold-formed from a flat annealed plate having length, height, and width dimensions. A plurality of slots (12,14) extend along the height dimension at regular intervals along the length dimension, thereby defining successive cell walls (16,18,20) between successive slots along the length dimension. Each cell wall has upper, central, and lower regions (28,30,32) along the height dimension, each region including a substantially flat base area (34,36,38) and fuel rod support structure (22,24,26) projecting integrally from the base area along the width dimension of the strip. The support structure in each of the upper and lower regions includes a relatively stiff, arched stop (22,26) which projects in a first direction and the support structure in the central region includes a relatively soft, arched spring (24) which projects in a second direction opposite the first direction.

Abstract: A nuclear fuel assembly grid (100) made from a plurality of interlaced corrugated metal strips (102-116) forming an egg-crate configuration so as to define plurality of four-walled cells (118) for receiving respective individual fuel rods (120). The spaced apart vertical bend lines (160,162) of the currugation define vertices (130,132) and consecutive body panels (164,166) which alternate generally inwardly and outwardly between consecutive bend lines. A vertical slot (168) extending from one of the strip upper or lower edges (176) into each panel midway between consecutive bend lines, and overlapping a slot from an interlaced strip to form an hourglass-shaped cell having opposed convex walls and opposed concave walls and four 90 degree corners (150). Spring (148) and stop (153) structure projects from each wall of a cell, for centering and supporting the fuel rod within the cell.