Abstract: In a method of measuring the contamination profile of the inner surfaces of a radioactively contaminated pipe embedded within a concrete structure in a nuclear reactor facility, the detecting surface of a detector to be inserted into the contaminated pipe is fitted with a movable shield plate or cover, which is moved by a specified distance and the radioactive contamination profile within a limited area of the inner surfaces of the pipe is measured in terms of the difference in radiation intensity measured in two states, one where the shield plate or cover is in contact with the detecting surface and the other where it is spaced from the latter.

Abstract: A Supervisory Sequential Controller Interface (SSCI) provides for automatic and manual sequencing of the sequential steps of multiple procedures simultaneously in a complex process facility while preserving operator supervisory control over each procedure. The SSCI includes an Executive Interface which gives the operator global control over all of the procedures and a Procedure Interface which is arranged such that the operator may ascertain the relevant information about a particular procedure, including the mode (auto/manual), the current step being executed and the relevant states of plant components and parameters for the current step. Multiple Procedure Interface screens may be displayed to monitor/execute multiple procedures running simultaneously.

Abstract: An apparatus for handling nuclear fuel rods, which include a mixed oxide fuel material, and for constructing fuel assemblies from the fuel rods, includes a store (9) constructed from radiation shielding material. The store includes a number of channels (10), each of which is adapted to receive a magazine (2) containing fuel rods. Removal and insertion of magazines from and into the channels is effected by a handling machine (29) which is remotely and automatically operated. Each of the channels is closed by a plug (11) which can be removed and inserted by the handling machine. The handling machine is able to remove a magazine from a selected channel and to deliver the magazine to either of two fuel assembly lines (16, 21). Each assembly line constructs a different type of fuel assembly from that of the other assembly line, and each assembly line is arranged in a separate shielded enclosure (15, 24).

Abstract: Changes in the value of the control element assembly position signal (26,28) are monitored over a preselected time period, and a determination is made whether these changes conform to a regular, predetermined pattern (S.sub.1), characteristic of normal control element assembly motion. If any change deviates (S.sub.2,S.sub.3) from the pattern by more than a permissible tolerance, a position invalidity signal is generated.

Abstract: A measurement chamber (18) having an upper and a lower region is at substantially the same elevation as a horizontal pipe (12) having a top region and a bottom region. An equalization line (14) fluidly connects the top region of the pipe (12) to the upper region of measurement chamber (18). A sample line (16) fluidly connects the bottom region of pipe (12) to the lower region of the measurement chamber (18). Heat junction thermocouples (22) generate a signal indicative of the level of fluid in the measurement chamber (12) which is equal to the level of fluid in the pipe (12). The signal is transmitted to a remote location by line (24).

Abstract: The invention provides a method and apparatus dispensing a liquid bait in a refillable manner. The invention provides a transparent bait station in which is mounted to a structure. A liquid bait is injected into the bait station to initially fill and then refill the bait station. The bait is a slow acting toxicant and attractant. The bait station is formed to allow access by bugs, but not by larger animals. The bait station is also able to protect the bait from wind and rain. The bait station prevents leakage of the toxicant if the bait station is tumbled or placed in an incorrect position. The bait station is able to hold two different liquid baits, which may be two different poisons, or a poison and an attractant. An embodiment of the bait station provides a series of inner walls to minimize the leakage of liquid bait, if the liquid bait station is tumbled.

Abstract: Methods and apparatus for enabling repeatable positioning of inspection and other service tools on an inner diameter of a shroud wall between a top guide and core plate in a boiling water nuclear reactor are described. In one embodiment, the delivery system includes a positioning unit configured to attach to a shroud head flange, a strong back assembly, and a rail assembly connected to the strong back assembly. The positioning unit includes a horizontal member having a plurality of slots and circular shaped openings to mate with seismic pins on the shroud head flange, a radial member and a z-axis adjustment assembly. The radial member extends from the horizontal member to the z-axis adjustment assembly. The z-axis adjustment assembly includes a mast coupling and an elongate screw threadedly attached to the coupling so that as the screw rotates, the coupling moves relative to the radial member. The strong back assembly includes a mast and an extension unit.

Abstract: A fuel assembly for a boiling water reactor comprises a plurality of first full-length fuel rods arranged in an orthogonal lattice, wherein each fuel rod is included in two rows of fuel rods perpendicular to each other, and a number of second fuel rods arranged in parallel with the first fuel rods and having the length considerably smaller than the length of the first fuel rods. The second fuel rods are arranged in the lower part of the fuel assembly in the space which is formed between a number of first fuel rods located adjacent to each other, that is, in a position which does not belong to the orthogonal lattice.

Abstract: The bypass opening of the tie plate of a fuel assembly of a nuclear reactor is provided with a flow restricting or check valve such that flow during normal operation upwardly through the tie plate and bypass opening is maintained. In the event of a loss of coolant accident, and degradation of a core spray sparger system, backflow leakage through the tie plate is minimized or eliminated by the valves, enabling the core spray sparger system to flood the core about the fuel assemblies and provide spillover coolant into the open top ends of the fuel assemblies. Additionally, because the fuel assemblies change in length over time, a uniform coolant flow distribution into the fuel assemblies upon loss of coolant accident is achieved by providing metering holes through the channels whereby each channel receives substantially the same flow of coolant from the flooded core.

Abstract: A spacer for retaining and positioning elongated elements at one or a plurality of levels in a nuclear reactor fuel assembly comprises a grid structure of joined-together sleeve cells. A coolant is adapted to flow upwards through the fuel assembly. The majority of the sleeve cells are provided with an upstream edge with a waveform. The edge is waveformed in such a way that the upwardly flowing coolant first encounters a peak of the wave which is disposed between the joints of the sleeves and thereafter a valley of the wave which is disposed at the joints of the sleeves. The peaks are arranged closer to a center of the sleeve cell than the valleys. Between the peaks and valleys, oblique edges are formed.

Abstract: A transiently unstable state of a boiling-water reactor is damped by measuring the oscillating neutron flux and, after a first threshold value is exceeded over a plurality of oscillation periods, the rate of increase of the oscillation is determined. Depending on the slope of the increase, and after a further threshold value (in particular one dependent on the rate of increase) for the oscillating flux is exceeded, a selection is made which one of various stabilization strategies for damping the oscillation should be triggered before a SCRAM becomes necessary. A hierarchy of stabilization strategies is available: blocking a power increase, for instance, in the control system, controlled slow reduction of the power, or rapid power reduction by a "partial SCRAM". The monitoring of the unstable state is effected with a system of sensors strategically distributed throughout the core and which redundantly measure the flux in one region of the core.

Abstract: A channel box for a nuclear-reactor fuel assembly (MOX fuel assembly) containing plutonium, capable of properly controlling the excess reactivity without mixing neutron absorber or burnable poison into a fuel rod, and a channel box for a nuclear-reactor fuel assembly which does not form any gap between the channel box and members containing burnable poison in the channel box and in which the burnable poison does not directly contact with reactor water.

Abstract: An air bag system for protecting an occupant in a motor vehicle against injuries resulting from a crash. The system is distinguished by an air bag with releasable partitioning, preferably breakaway stitching, that provides a variable-size inflatable volume and by a means to control the level of inflation. These features allow the present invention to provide optimum protection regardless of whether the occupant is restrained by a seat belt and regardless of whether the crash speed at impact is moderate or severe. The air bag of the invention accommodates the occupant who is wearing a seat belt restraint by inflating to a relatively small inflated volume with a varying internal pressure depending on the crash speed. It accommodates the occupant who is not belted and is in a vehicle traveling 21 mph or faster at the moment of impact by inflating to a larger inflated volume. Thus, the invention provides protection that is appropriate to and optimal for specific crash conditions.

Abstract: A pair of openings are formed using an EDM technique. A pair of clamps are inserted into the openings and moved toward each other until such time as the inboard edges of the two openings are engaged. A pair of EDM cutters are used to cut a pair of slots which extend from one opening to the other. Upon completion of these slots, the sample, which remains clamped between the two clamps, is withdrawn and lowered back down the conduit to a remote collection point.

Abstract: Zirconium-based components for nuclear reactors are disclosed whereby a rare earth or other metal which preferentially concentrates hydrogen when in contact with zirconium is dispersed as a second phase throughout a zirconium-based matrix. The morphology and distribution of the two-phase material is controlled such that the second phase, internal hydrogen absorbing particles, are provided as spherical particles, randomly distributed, to minimize the effects of the occluded hydrogen.

Abstract: A device for collecting and cooling reactor-meltdown products from a reactor pressure vessel includes an antechamber disposed below the reactor pressure vessel and an expansion chamber for the reactor-meltdown products. A channel which is disposed between the antechamber and the expansion chamber has a partition being destructible by the reactor-meltdown products. A closure element which connects a coolant reservoir to the expansion chamber is destructible by the reactor-meltdown products. A method for collecting and cooling reactor-meltdown products from a reactor pressure vessel includes collecting reactor-meltdown products in an antechamber disposed below the reactor pressure vessel and keeping them in the antechamber for a predetermined time interval. A partition disposed between the antechamber and an expansion chamber is destroyed with the reactor-meltdown products. The reactor-meltdown products penetrate from the antechamber into the expansion chamber and are spread in the expansion chamber.

Abstract: Seed-blanket type nuclear reactor cores (10,100) are employed to burn thorium fuel with conventional reactor fuels, including nonproliferative enriched uranium, and weapons or reactor grade plutonium. In a first embodiment, the core (10) is completely nonproliferative in that neither the reactor fuel, nor the generated waste material, can be used to manufacture nuclear weapons. In a second embodiment of the invention, the core (100) is employed to burn large amounts of weapons grade plutonium with the thorium, and provides a convenient mechanism by which stockpiled weapons grade plutonium can be destroyed and converted into electrical energy. The cores of both embodiments are comprised of a plurality of seed-blanket units (12, 102) which have centrally located seed regions (18,104) that are surrounded by annular blanket regions (20,106). The seed regions contain the uranium or plutonium fuel rods (22,110), while the blanket regions contain thorium fuel rods (26,118).

Abstract: An actuator for performing work in a nuclear reactor is described. In one embodiment, the actuator includes an x-axis linear slide assembly, a y-axis linear slide assembly, and a z-axis linear slide assembly. The x-axis linear slide assembly is mounted to a junction box, the y-axis linear slide assembly is mounted on a carriage of the x-axis assembly, and the z-axis linear slide assembly is mounted on a carriage of the y-axis assembly. The actuator also includes motor assemblies coupled to respective linear slide assemblies. Each motor assembly includes a motor and a resolver sealed in a leakproof can. Pulley-timing belt assemblies couple each motor to a respective lead screw. Specifically, a drive pulley is connected to a rotor shaft of each motor, and a lead screw pulley is secured to an end of each lead screw. Each pulley-timing belt assembly also includes an idler pulley, and a belt extends around the lead screw pulley, the idler pulley, and the drive pulley.

Abstract: A novel high-purity polymer dispersant and sludge conditioner added to the feedwater entering the secondary side of a nuclear steam generator for minimizing the accumulation of metal-oxide deposits within the nuclear steam generator during the continuing operation of the generator is disclosed. The high-purity polymer is selected from a group consisting of acrylic acid polymer, methacrylic acid polymer, acrylate polymer, methacrylate polymer, copolymers, and terpolymers, acrylate/acrylamide copolymer, acrylate/methacrylate copolymer, terpolymers, and mixtures thereof. Methods of making and applying the polymer dispersant and sludge conditioner are described. Means for removing the metal oxides and polymer from the blowdown stream are disclosed.

Abstract: A conveyance system provides for storing, monitoring, and retrieving (multi-purpose) canisters "MPC" for intermediate storage of spent fuel rods from nuclear power plants. The system includes a shielded transport system, an access corridor shielded for radiation, a lifting transport conveyance, an elevation chase, a dry-pool, seismic bracing to support the canisters in storage, associated shielding to confine radiation to the dry-pool, and air manifold system for cooling, and facilities to add alternative liquid radiation shielding around the canisters in the dry pool.A RR-locomotive moves a RR-car having a radiation shielded transport container to communicate with a dry-pool access corridor. A bridge crane carries an "MPC" through the corridor to a vertical chase which accesses to the dry-pool. The bridge crane places the "MPC" at a cooling vent manifold. A seismic brace engages the "MPC" secure to the dry-pool wall. A configuration of radiation shielding confines emissions.