Abstract: In order to provide a relatively inexpensive water-tight telescopic enclosure which can extend automatically upon demand, a tubular extension piece is reciprocally mounted on a container-like hook box structure. A tube seal which interconnects the hook box and the tubular extension provides a watertight connection between the two members and also provides an air space in a folded portion in which air can collect and produce buoyancy as the hook box is lowered into water. The tubular extension also has a larger cross-sectional area than the hook box and thus produces additional buoyancy. When the hook box is lowered into water the extension piece automatically floats upwardly to prevent the intrusion of water into the interior of the hook box and thus prevent contamination of pieces of apparatus enclosed therein.

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: An apparatus for hydrostatic pressure testing of tubular products that enables short segments of the tubular product to be individually tested under conditions simulating a capped tube hydrostatic test. The apparatus includes a first seal bladder and gripper member assembly connected to a second seal bladder and gripper member assembly by a connecting member that allows relative axial movement between the two assemblies. A fluid outlet port is provided in the connecting member to introduce pressurized fluid into the short segment of the tubular product between the seal bladders of the two assemblies. Since the first seal bladder and gripper member assembly is axially movable relative to the second seal bladder and gripper member assembly, an axial stress as well as a hoop stress will be induced in the tubular product during testing.

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: A system for performing laser welding comprises an optical lens for receiving an incoming laser beam and for dividing the laser beam into a number of different beam segments. The top surface is defined by a number of different surfaces for respectively dividing the laser beam into the number of beam segments. The optical lens has a convex bottom surface for focusing and directing the beam segments onto a respective number of welding locations. Preferably, the laser welding system is used to simultaneously perform five welds on an improved spacer grid assembly which has a cylindrical member located at each intersection of the spacer strips. By simultaneously performing the five requisite welds, the welding time is significantly reduced. Also, the welding process is simplified since the system only has to be in one position to perform all of the welds at each intersection.

Abstract: A tool system features an EDM crack removal head which can be positioned within a nozzle/thermal sleeve and then oscillated in a vertical and horizontal directions to enable precise material removal, leaving the surface free of cracks and in a condition for rewelding if required. If a crack is found in a surface which is covered by a thermal sleeve, then a small specialized EDM cutting head, which can be delivered from the under side of the reactor head and has an ability to pass through the ID of the thermal sleeve, is used. The head enables the sleeve to be cut and allow a portion of the sleeve to be removed. The crack can then be removed using a crack removal type of head.

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: A self-sampling corrosion monitor is structurally adapted to be connected to the blowdown system or other piping systems external to a steam generator. The monitor includes a pump for providing positive solvent flow through the monitor, and a regenerative heat exchanger using recovered heat at the outlet. Magnetite is also added to a sludge cup within the corrosion monitor vessel to simulate real time measurement of short-lived corrosion conditions in the steam generator. In addition, the available corrosion monitoring equipment is modified to provide automatic microprocessor-controlled range selection. Still further, data acquisition, storage, and display techniques are modified.

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: By using AVLIS or other methods capable of providing a depleted isotopic mixture, troublesome isotopes such as Gd.sup.154, Gd.sup.156 and Er.sup.166 are selectively removed from naturally occurring isotopic mixtures, while avoiding the additional costs associated with complete fractionation of the mixture. Such mixtures can be used to provide a burnable nuclear fuel absorber having a selectively depleted isotope or isotopes. In particular, the invention concerns burnable absorbers containing erbium with a depleted 166 isotope, gadolinium with a depleted 156 isotope or with depleted 154 and 156 isotopes, and methods for making such absorbers.

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 polisher is supported on either a frame/arm arrangement or on a vehicle which is guided by track, and is arranged to be energized to polish a predetermined surface of an annular flange or the like, when relative movement is sensed between the polishing element and the surface to be polished. The polishing arrangement can be motor driven so that the polisher can be left to polish the surface in the absence of an operator.

Abstract: A retainer is for retaining a grid on a fuel assembly. The retainer has at least one aperture at one end thereof for receiving a shoulder on a guide control tube and legs on the other end thereof for welding to the grid. The one end of the retainer is captured between the shoulder and a surface on the bottom nozzle of the fuel assembly when the guide tube is attached to the bottom nozzle. The retainer reduces the rotation of the guide tube resulting from torquing of the screws which connect the guide tube to the bottom nozzle thereby increasing the integrity of the assembly.

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 latch tool features two elongate arms which extend down along either side of a control rod. Rotatable actuating rods are mounted on the arms. The upper ends of the actuating rods are provided with cranks which engage in slots formed in an actuating disc. As the disc is rotated, the cranks rotate the actuating rods and swing cam-like members, which are fixed to the rods, into position under an unlatching handle. In the preferred embodiments, the actuating disc is threaded onto the exterior of a rotatable input member, so that after the cam-like members are swung into position, the actuating disc threads its way up the input member in a manner which pulls the cam-like members upwardly and pulls the unlatching handle. In addition to the cam-like members which actuate the unlatching handle, lifting cam-like members may additionally be provided to fit in under a lifting handle of the control rod, and facilitate lifting of the control rod out of its position.

Abstract: A boiling water reactor control rod drive housing support bars having wing assemblies to limit the travel of a control rod in the event that a control rod housing is ruptured. The wing assemblies are placed on support bars located in rows on opposing sides of the control rod drives. Each wing on the wing assemblies supports a quadrant of a control rod drive. The wing assemblies may be rotated from an operation position to a service position to allow replacement of the control rod drives.

Abstract: A boiling water reactor control rod drive housing support bars having radiation shields to limit the travel of a control rod in the event that a control rod housing is ruptured and protect persons working under the reactor vessel from radiation exposure. The radiation shield includes radiation shield cups for surrounding the bottom portion of a control rod drive. The radiation shield cups are placed on support bars located in rows on opposing sides of the control rod drives. The radiation shield may be easily raised and lowered automatically by the control rod drive installation/removal machine.

Abstract: A fuel element for a nuclear reactor is described having a zirconium alloy cladding tube, with a thin coating of a metal silicate and particles of enriched boron-containing compound burnable-poison particles, such as ZrB.sub.2, deposited from a liquid suspension which includes a polymer binder material and water and/or alcohol as a diluent.