Abstract: Fluid flow rates are determined with a nonradioactive tracer agent in the operation of a water cooled nuclear fission reactor employed for driving electrical power generators. The technique is proposed for use to routinely calibrate other flow measuring means such as restricted flow nozzles.

Abstract: A method for manipulating motion ghosts is disclosed. The method includes acquiring two image data sets, each including a time averaged image component and a ghost component and processing these components to separate the ghosts from the desired image and further using the ghost information to produce a dynamic image. Motion monitoring systems are not required. Improved scan times and noise control are allowed over previous methods.

Abstract: A method for producing dynamic images from a ghosted MR image is disclosed. The method includes acquiring an image data set including a time averaged image component and a ghost component and processing these components to produce a dynamic image. A motion monitoring system is not required as in conventional cine magnetic resonance imaging.

Abstract: An x-ray tube rotor controller uses the main high voltage inverters for acceleration. The rotor controller includes a DC voltage source, and a rotary anode drive circuit including a rotary anode motor designed as an induction motor. A first inverter circuit has a full bridge arrangement for accelerating the anode using a first switch to connect the induction motor to the full bridge output, and also generates high voltage for the x-ray tube. Once the anode is up to operating speed, the first switch is disconnected from the rotor causing the rotor to coast. Alternatively, a second small inverter may be employed for maintaining the rotor at speed during x-ray exposure, rather than allowing the rotor to coast. In such an instance, the first switch is disconnected from the rotor when the motor reaches a rated anode speed, and a second switch then connects the motor to the second inverter to maintain the rated anode speed.

Abstract: A detachable seal assembly for a pressurized constant process oven through which a flat filament is passed and which seals the oven against the environment surrounding the oven including a resilient aperture formed by opposed flaps which extend from a transverse portion in the direction of movement of the filament to sandwich the filament. Compression is provided to the seal assembly such that the friction of filament movement tends to stretch the flaps to seal the resilient aperture about the filament. The seal assembly includes a clamp to enable ready replacement to minimize process down time during replacement.

Abstract: An x-ray beam stop for high energy x-ray devices comprises a laminate structure of multiple layers of different Z materials which may include lead (Pb) and arranged in progressive Z order for a predetermined x-ray detector orientation.

Abstract: A reactor core with each fuel rod surrounded by an individual cylindrical channel is disclosed. This individual channel on each fuel rod provides thermal hydraulic and heat transfer advantages to enable all fuel rods within the fuel bundle to uniformly approach their own thermal limits. The preferred fuel rod pitch is a triangular pitch between the individual fuel rods as they are discretely surrounded by their own channel. The new triangular geometry provides for more uniform (flat) power distributions within all fuel rods--and hence all groups of fuel rods. Bypass flow is introduced uniformly between the fuel rod channels, rather than heterogeneously in the channel gap and water rods as in present BWR fuel designs. Individual fuel rod channels can be orificed differently, as required, to match inlet flow to fuel rod power output to maintain uniformity between all fuel rods as they approach their respective thermal limits.

Abstract: A method for MR imaging in an inhomogeneous magnetic field substantially without inhomogeneity induced artifacts is disclosed. The method includes acquiring more than one line of K-space per pulse sequence. The K-space data is acquired in partial line segments. The method allows shorter imaging times and higher image quality than conventional imaging methods for inhomogeneous fields.

Abstract: A liquid metal cooled nuclear fission reactor plant having a passive auxiliary safety cooling system for removing residual heat resulting from fuel decay during reactor shutdown, or heat produced during a mishap. This reactor plant is enhanced by a backup or secondary passive safety cooling system which augments the primary passive auxiliary cooling system when in operation, and replaces the primary system when rendered inoperable.

Abstract: An apparatus for solvent extraction processes utilizing countercurrent flow of streams of an aqueous phase and an organic phase, such as the Purex process for uranium recovery. The invention comprises contouring the fluid passing orifices in the column phase dispersing perforated plates to impede droplet coalescence of the dispersed phase.

Abstract: An electrode probe suited for employment as an electrical potential reference electrode in an aqueous, high pressure, high temperature, and high radiation field environment such as the core of a nuclear reactor is described. The electrode is a brazed and welded assembly consisting of only ceramic and metal parts including a sapphire base which is brazed to a kovar/stainless steel housing, welded in turn, to a coaxial cable assembly for signal transfer. The base incorporates an integrally formed pedestal through which a conductor wire extends and over which is positioned a selectively coated cylindrically shaped sealing retainer. The device is particularly suited for employment with a silver/silver chloride electrode system.

Abstract: To measure fuel rod-centering forces exerted by double-acting springs assembled with different pairs of ferrules in a nuclear fuel bundle spacer, a gauge is provided to include an alignment rod and a probe carried by a handle for insertions into the ferrules of a ferrule pair. The alignment rod loads the side of the spring acting in its ferrule, while the other spring side exerts its fuel rod-centering force on a plunger mounted in the probe. The plunger is mechanically linked to a load cell which provides an electrical readout of the spring force.

Abstract: A conventional low pressure coolant injection system for boiling water reactors is provided. With the modification, the cross tie conduits and associated valves remain open between two LPCI divisions. On the occasion of an LOCA, the LPCI pumps are activated and injection valves for each of the LPCI divisions are opened to commence coolant injection in the recirculation loops in simultaneous fashion. However, the rate of flow of water coolant within each injection system is controlled by a hydraulic resistance, which is selected to achieve reactor core cooling within requisite time and in requisite quantities from one injection path. Thus, even though coolant water may flow through a rupture within one recirculation loops, sufficient water will be injected in the other loop to achieve core cooling.

Abstract: An expanded reactor core capacity is achieved within the constraints imposed by the diametric extent of the current advanced boiling reactor (ABWR). This enhanced core capacity is achieved through the utilization of a scalloped shroud structure in conjunction with modified control rod designs. The core diameter is expanded toward the reactor vessel interior wall to establish a minimum distance therebetween representing a minimum value thereof avoiding neutron fluence induced vessel embrittlement. The control rods servicing peripheral fuel assemblies are configured having either a T-shaped blade configuration or an L-shaped blade configuration depending upon the parallel orientations of the peripheral fuel assemblies.

Abstract: Apparatus and method are described for providing a discrete readout of the collapsed water level within a boiling water reactor. An elongate gauge housing is mounted within the reactor vessel extending through the collapsed level from a steam environment into a boiling water environment. A serially coupled sequence of junction defining thermocouple element pairs are positioned within the gauge housing and are arranged with a heating assembly to generate an output signal which corresponds with the water level. Also located under the influence of the heating assembly are reference thermocouples, one providing a reference output corresponding with the instantaneous temperature of the boiling water environment and the other providing a reference output corresponding with the steam environment above the collapsed water level. The signals from the reference thermocouples and the serial coupled level determining thermocouple structures are then treated to define instantaneous water level.

Abstract: An improved spacer is disclosed which contains an Inconel grid and a Zircaloy surrounding band. The Inconel grid can be fabricated from the extremely thin and highly elastic spring metal utilizing a modification of a prior art cell construction that includes paired inwardly bent vertical spring legs with cantilevered and rod encircling upper and lower arm pairs The spring legs extend at spaced apart locations between the upper and lower arm pairs and have a medial spring rod contacting portion for biasing the rods into stops on the rod encircling arm pairs. The springs at the upper and lower ends are provided with spring dimple stops to prevent over stressing of the spring during assembly or handling of the fuel bundle into which the spacer is incorporated. The rod encircling arm pairs have an offset from center where the two arms meet at their distal ends to complete encirclement of the rods. This offset from center enables the cells to be fastened in cell pairs at their respective embracing arms.

Abstract: A nuclear reactor core assembly includes a support plate having a plurality of inlets for channeling water to a core lattice fixedly joined thereto. The lattice includes a plurality of flow channels, each including a respective separately removable fuel bundle. In a preferred embodiment, the core lattice includes a plurality of flow dividers joined together for allowing unrestrained expansion and contraction thereof, and which prevent crossflow of water therebetween.

Abstract: Water testing means for monitoring circulating water coolant in service within a water cooled nuclear reactor system is disclosed. The invention is an improvement in such water testing means and comprises a preconditioning of selected sample specimens of water with a pH adjustment for inhibiting unbalancing an equilibrium in solution of water coolant with ion solutes.

Abstract: A nuclear reactor system pressure vessel comprises a steel inner liner part, an intermediate insulative layer part and an outer pre-stressed concrete part encasing these parts. Use of the pre-stressed construction allows for construction of pressure vessels of larger size than heretofore, and this coupled with utilization of squatter reactor cores allows natural convective circulation in the reactor vessel of the heated water pool in the higher capacity systems currently being introduced. The reactor pressure vessel because of its suitability allows enhanced natural steam separation in the vessel and eliminates need for use of centrifugal steam separators. The outer vessel part can be a cast single piece structure or it can be an integrated concrete segment assembled structure embodying pre-stressing tendons arranged in various orientations to effect pre-stressing.

Abstract: To mechanize the accumulation of nuclear fuel rods into fuel bundle groups, fuel rods are uploaded onto an input table from a succession of trays containing fuel rods of different rod types. The serial number of each fuel rod is read during procession across the input table to an output queue. An input elevator uniformly distributes fuel rods from the output queue to plural levels of an accumulation rack until each level contains an identical number of fuel rods of each rod type necessary to completely assemble one fuel bundle. An output elevator then empties the accumulation rack, one level at a time, to an output table, from which the fuel rods from each level are downloaded into separate bundle trays.