Abstract: Apparatus for reducing the pressure in a pressurizer of a pressurized water type cooling system for a nuclear reactor when a predetermined pressure value is reached including a closed tank which is provided with coolant fluid outlet and inlet pipes or conduits which extend respectively from the bottom and top of the tank, and which are connectable, via a normally closed self-actuated mechanical pressure relief valve, to a spray nozzle in the upper end of the pressurizer and to the vapor space within the upper portion of the pressurizer respectively. The tank is disposed vertically above the pressurizer and is partially filled with liquid coolant which is subcooled for the pressure existing in the pressurizer, while the four-way valve is set to open in response to the predetermined pressure being reached in the pressurizer.

Abstract: A safety coolant injection system for nuclear reactors wherein a core reflood tank is provided to afford more reliable reflooding of the reactor core in the event of a break in one of the reactor coolant supply loops. The reactor vessel, reactor coolant supply loops, emergency water storage tank and pump modules are arranged in separate compartments in the containment structure to control the flow of spilled coolant. An integrated containment spray system and normal cooldown system are also described.

Abstract: A plunger element which slides axially in a bore in a dashpot element secured to the internals of a steam generator is biased against the shell of the pressure vessel by a series of Belleville springs. The plunger and dashpot element form a chamber having a volume which varies as the width of the gap between the pressure vessel shell and internals changes due to differential thermal expansion, and pressure expansion of the shell. A collapsible reservoir provides an incompressible fluid to the variable volume chamber under urging of the ambient pressure in the pressure vessel through a metering passageway to maintain the chamber full of fluid.

Abstract: A hydrostatic seal for sealing an annular gap between two flat substantially horizontal coplanar surfaces, and particularly a gap in a nuclear reactor cavity which comprises a generally flat annular plate of a width sufficient to span the gap between the two surfaces, compressible annular sealing rings or gaskets disposed on the bottom surface of the flat annular plate for sealingly engaging the two flat surfaces when a downward force is exerted on the plate, and a plurality of fastening arrangements, distributed along the center line of the plate, for releasably fastening the plate in a position to span the gap and exert a downward force on the plate.

Abstract: The fissile inventory required in operating a negative power coefficient nuclear reactor in an electric power generating system is reduced by cycling the load imposed on the system when 100% power can no longer be maintained at equilibrium due to xenon poisoning in order to induce an oscillation in the xenon concentration which is in antiphase wtih the power requirements so that 100% power can be maintained at least during part of the day. The load can be progressively reduced by a preset amount each night or a xenon suppression controller which forecasts the xenon reactivity at the time selected for a return to full power as a function reactor history, current reactor flux and an arbitrary load schedule can be used to determine the maximum reduced power level that will permit operation at full power at the selected time.

Abstract: An inadvertent approach to criticality in a nuclear fueled electric power generating unit is detected and an alarm is generated through on-line monitoring of the neutron flux. The difficulties of accurately measuring the low levels of neutron flux in a subcritical reactor are overcome by the use of a microcomputer which continuously generates average flux count rate signals for incremental time periods from thousands of samples taken during each such period and which serially stores the average flux count rate signals for a preselected time interval. At the end of each incremental time period, the microcomputer compares the latest average flux count rate signal with the oldest, and preferably each of the intervening stored values, and if it exceeds any of them by at least a preselected multiplication factor, an alarm is generated.

Abstract: A method and apparatus for cooling waste gases of a temperature in excess of 800.degree. C. using radiant heat transfer to a plurality of fluidized beds. Solid particulate material is contained within a housing and divided into a plurality of fluidized beds by baffle means and fluidizing gas injected upwardly through the solids, without transfer of solids from the upper surface of a bed to adjacent beds. The hot waste gas is cooled by radiant heat transfer through the surfaces of the beds. Heated solids are cooled by either flow through the housing and cooling of the same outside the housing, or by coolant passed through heat transfer tubes that are positioned within the beds of solid particulate material.

Abstract: A method for fabricating a steam generator and a steam generator wherein primary coolant tubes are sleeved in and in the vicinity of a tubesheet. A smooth transition region is formed between stock primary coolant tubes and sleeved portions thereof in such a manner that no sites for accelerated corrosion are formed. In addition, an adequate volume of material is provided in the transition region to withstand thermal and mechanical stresses and chemical attack. The sleeved tube is preferably thermally treated for improved corrosion resistance.

Abstract: A servicing machine for a steam generator is accurately set up in the generator channel head with a pivoted arm mounted for rotation in a plane parallel to the tubesheet. The angular position of the arm, the longitudinal position of a carriage mounted on the arm and the vertical position of a platform on the carriage are remotely controlled to maneuver a probe used in mapping the precise location of the thousands of holes in the tubesheet. Various operations are then performed at each precise hole location by tools carried by the arm mounted carriage to prepare for installation of new tubing. The operation of a pair of remotely controlled pivoted arms, one on each side of the channel head divider plate, is coordinated to automatically position the ends of U-shaped tubes in corresponding holes in the tubesheet on opposite sides of the divider plate and to secure the same in place.

Abstract: A cam-controlled boring bar system (100) includes a first housing (152) which is rotatable about its longitudinal axis (154), and a second housing in the form of a cam-controlled slide (158) which is also rotatable about the axis (154) as well as being translatable therealong. A tool-holder (180) is mounted within the slide (158) for holding a single point cutting tool. Slide (158) has a rectangular configuration and is disposed within a rectangularly configured portion of the first housing (152). Arcuate cam slots (192) are defined within a side plate (172) of the housing (152), while cam followers (194) are mounted upon the cam slide (158) for cooperative engagement with the cam slots (192). In this manner, as the housing (152) and slide (158) rotate, and as the slide (158) also translates, a through-bore (14) having an hourglass configuration will be formed within a workpiece (16) which may be, for example, a nuclear reactor steam generator tube support plate.

Abstract: A minimum-wear through-bore (16) is defined within a heat exchanger tube support plate (14) so as to have an hourglass configuration as determined by means of a constant radiused surface curvature (18) as defined by means of an external radius (R3), wherein the surface (18) extends between the upper surface (20) and lower surface (22) of the tube support plate (14). When a heat exchange tube (12) is disposed within the tube support plate (14) so as to pass through the through-bore (16), the heat exchange tube (12) is always in contact with a smoothly curved or radiused portion of the through-bore surface (16) whereby unacceptably excessive wear upon the heat exchange tube (12), as normally developed by means of sharp edges, lands, ridges, or the like conventionally part of the tube support plates, is eliminated or substantially reduced.

Abstract: A support system for supporting a pressurizer safety and relief valve system above a pressurizer vessel of a pressurized water reactor, which comprises an upper ring section that rests on the dome of the pressurizer, a lower ring section having sleeves attached thereto, and a plurality of arcuate connecting sections, conforming to the shape of the dome. Columnar supports for the valve system are supported in the sleeves on the lower ring and collars are attached to the arcuate sections stabilize the columnar supports.

Abstract: A pressurized water reactor system having circulation means outside the containment vessel for the circulation of loss of coolant emergency water is provided which prevents exposure of such water to the atmosphere. The system includes an enclosure, separate from the containment vessel, the interior of the enclosure being sealed to the atmosphere and containing a pumping means, and encased inlet and outlet conduits communicating between the interior of the containment vessel and the pump means within the enclosure. The enclosure may also contain a heat exchange means, while the emergency water storage tank can be positioned in the containment vessel, in the enclosure, or separate from both. Provision is also made for use of the pump in the enclosure for circulation of residual heat removal coolant water.

Abstract: A device for monitoring leakage of fluid across a seal in a component connected to a pressurized fluid system. The device includes a housing defining a chamber which includes an inlet for receiving fluid leaking across the seal and an outlet. A plate having an orifice is disposed in the chamber transverse to the longitudinal axis of the chamber and between the inlet and outlet for dividing the chamber into a first chamber volume for receiving fluid through the inlet and a second chamber volume for receiving fluid through the orifice and for discharging the fluid through the outlet. A plug is movably mounted for adjusting the open area in the plane of the orifice in the plate.

Abstract: A process for removing dissolved oxygen from an aqueous medium, using hydrazine to react with the oxygen, where the aqueous medium is contacted with a catalyst bed of palladium or platinum metal dispersed on a solid carrier, at ambient temperatures. The catalyst bed effects reaction of the hydrazine with the dissolved oxygen to provide residual oxygen contents of below 10 ppb. Preferably, the hydrazine is intimately mixed with the aqueous medium prior to contact with the catalyst bed. The process is especially useful in removing dissolved oxygen from recirculating aqueous medium of a steam generation system, where the hydrazine-containing aqueous medium is contact with the catalyst bed after passage through the condenser pump but prior to the feedwater heaters.

Abstract: A nuclear reactor having a remotely removeable and replaceable thermal and/or radiation insulating shield for the head. This shield is formed of interlocked integrated shielding units of thermal insulating material. Each unit has a vertical member and a horizontal member. Each unit has a lifting-and-lowering rod on its top and it may be raised vertically by a remotely operable clamp engaging the head. The interlocking surfaces of adjacent units are so formed that when any unit is raised or lowered vertically its interlocking surface readily slides along the interlocking surfaces of the units adjacent to it with which it is interlocked.

Abstract: A plumb nozzle for a nuclear fuel assembly having asymmetric loading of the fuel mass comprising a raised protuberance on the handling tool gripper finger engaging surface of the nozzle to compensate for skewing caused by the asymmetric fuel loading. The protuberance is positioned to be engaged by a gripper finger during handling, loading, or unloading of the fuel assemblies and extends downwardly a predetermined distance with respect to the other gripper finger engaging surfaces so that the fuel assembly hangs plumb.

Abstract: A universal dowel pin system (10) for properly aligning any one of a plurality of workpiece fixtures (12) relative to a machine tool table (14) comprises a dowel pin (20) which has a square-shaped base section (22) adapted to be dimensionally customized so that the width dimension thereof is substantially the same as the width dimension of the space defined between the sidewalls (18) of the machine tool table T-slot (16), while the upper pin section (24) of the dowel pin (20) has a diametrical dimension which is substantially the same as the uniform or standardized diametrical dimension of a bore (30) which may be defined within an insert (28) or directly defined within the particular workpiece fixture (12).

Abstract: A filter system wherein a hollow tubular member having an imperforate wall with a plurality of slots therein is coaxially positioned within a perforated mandrel that supports a ceramic bag filter. Gases to be filtered pass through the bag filter and deposit particulate matter thereon, enter a chamber between the perforated mandrel and the hollow tubular member, and are directed through the slots into the interior of, and are discharged from an open end of the hollow tubular member. Vapor phase contaminants in the gas can also be removed by providing a bed of solid absorbent material in the hollow tubular member such that the gas contacts the solid absorbent material and the vapor phase contaminant is removed prior to discharge of the gas from the open end of the hollow tubular member.

Abstract: A cable connection hood for housing a single or multiple socket connector, has a pair of mating wall sections that have abutting flanges and contain spacer blocks in various predetermined reconfigurable patterns. A wall section has a support flange spaced from an inwardly directed lip along the front thereon, with the spacer blocks fitting between the support flange and the lip. The spacer blocks comprise center portion blocks and end blocks and have means thereon for securement within the mated wall sections. The connector hood is usable with either round or flat cables and has means for preventing dislocation of socket connectors, contained therein, from card edge connectors during vibrations or shocks.