Abstract: An immersion based ultrasonic inspection system is disclosed which is used to interrogate the bore and near bore material of turbine and generator rotors by passing ultrasonic search units through the rotor bore. This system utilizes variable focus array inspection transducers in a shear mode inspection of the near bore material. A ranging transducer is provided which is used to correct the surface time of the inspection beam. A mapping transducer and blind bore sensor allow diameter mapping of the rotor bore as well as a blind rotor end sensing as the scan head carrying the transducers enters the bore. A scan head centering device or chuck deploys four radial arms to center and support the scan head. Each arm has a roller attached to the end which contacts the bore and rolls along so that the bore will not be damaged as the scan head passes through the bore.

Abstract: A device for monitoring the irradiation of bulk material composed of a carrier body having an outer surface formed to present a plurality of facets and constructed to receive a radiation sensor on each facet; and a plurality of radiation sensors each removably mounted on a respective facet of the carrier body.

Abstract: A passive safety system for a nuclear reactor is comprised of a first subsystem for circulating water solely by natural convection from a first branch to a second branch of a reactor coolant circuit with the circumvention of a steam generator for removing decay heat from the reactor coolant circuit at any pressure. The first branch guides heated water from the reactor vessel into the steam generator and the second branch guides cooled water from the steam generator into the reactor vessel. The first subsystem includes a heat exchanger for cooling water flowing from the first branch and prior to being introduced into the second branch and a first valve for allowing flow of water from the first branch into the second branch solely in response to a parameter value pertaining to operational safety. There is also provided a second subsystem for introducing stored cold water solely by gravity into the reactor vessel for making up for lost water in the reactor coolant circuit at any pressure.

Abstract: A tension loaded energy dissipating support member includes multiple successively longer metal straps all connected at each end to an end connector with the longer straps, and preferably the shortest strap, bowing outward laterally such that as the tensile load increases, the straps, beginning with the shortest, successively plastically deform to dissipate shock energy. The initial bowing, type of material, and relative dimensions of the straps can be varied to obtain the desired load supporting and energy dissipating characteristics.

Abstract: The present invention provides a rule based process control system which automatically learns how to control a process by inducing control rules from the process as it changes. During process operation data samples from the process are collected which include the controllable variables in the process along with the dependent variable (goal or goals) of the process. If a sample is not predicted by the current rules that control the process, new rules are induced from the new sample and previously collected samples by creating a decision tree. The controllable variable having the greatest effect on the goal occupies the highest tree node. New rules are produced from the decision tree which predict process behavior based on the new and old samples. From these new rules, control rules which satisfy system constraints and improve on the goal(s) are selected. The control rules are then used to control the process until another sample is not predicted by the new rules.

Abstract: A submerged, self-supporting, flexible piping system for conducting fluids to and/or from a moored, floating vessel to a fixed location external of the vessel. Self-support is achieved by controlling the density of the piping walls to establish neutral buoyancy of the filled submerged piping system.

Abstract: A vent system for controlling hydraulically actuated drive means for selectively moving pluralities of rod clusters respectively connected to the plurality of drive means between fully inserted positions within the lower barrel assembly of the vessel in telescoping relationship with fuel rod assemblies contained therein, and a fully withdrawn position. Each drive means responds to the reactor coolant fluid pressure and includes a leakage passage and an outlet channel through which a leakage flow may pass under control of the vent system, the latter comprising a valve arrangement, flow restrictors and a common orifice through which the outlet channels are selectively connected to essentially ambient pressure, for establishing a pressure differential within each drive means producing a net force for moving the drive rods and associated clusters to the withdrawn position at which the drive means mechanically latch the fully withdrawn clusters for mechanically supporting same in the fully withdrawn position.

Abstract: An array of plural rod guides each housing therewithin corresponding pluralities of rods, as disposed in parallel axial relationship within the cylindrical sidewall of the inner barrel assembly of a pressurized water reactor, defines a plurality of peripheral regions between the inner circumferential surface of the cylindrical sidewall and the peripheral edges of the array. A plurality of modular formers is installed within the respective plurality of peripheral regions, at each of one or more banks of predetermined, respective elevations within the inner barrel assembly. Each modular former comprises a pair of parallel former plates having arcuate outer edges corresponding to the interior circumference of the cylindrical sidewall and chordlike inner edges contoured to correspond to the juxtaposed peripheral edge of the array, and a vertical column extending between and rigidly interconnecting the associated plates of a pair.

Abstract: A method is described for detecting and correcting for isotope burn-in during-long term neutron dosimetry exposure. In one embodiment, duplicate pairs of solid state track recorder fissionable deposits are used, including a first, fissionable deposit of lower mass to quantify the number of fissions occuring during the exposure, and a second deposit of higher mass to quantify the number of atoms of for instance .sup.239 Pu by alpha counting. In a second embodiment, only one solid state track recorder fissionable deposit is used and the resulting higher track densities are counted with a scanning electron microscope. This method is also applicable to other burn-in interferences, e.g., .sup.233 U in .sup.232 Th or .sup.238 Pu in .sup.237 Np.

Abstract: A position sensing mechanism, for use with a nuclear fuel transfer system which employs an underwater cart having a pivotable container to receive fuel assemblies, employs mechanical elements below water and a cable which carries movement of the mechanical elements to a switch assembly at a dry location. The mechanical elements include an anchor element which is affixed to an upender mechanism, which selectively moves the container between horizontal and upended positions when the cart is located at a fuel transfer station, and a feeler mechanism which is displaced by the cart. The feeler mechanism includes a pivotably mounted swing arm and one or more pulleys. The cable is attached to the anchor elements and is guided by the pulleys. The switch assembly includes a further pulley having cams to actuate microswitches when the cable is displaced by the anchor element and feeler mechanism. A temperature compensator is spliced into the cable to keep its length constant despite temperature variations.

Abstract: An annular ring seal for establishing a permanent seal across an annular thermal expansion gap defined between a peripheral wall of a nuclear reactor vessel and a containment wall, which containment wall is spaced apart and surrounds the peripheral wall of the reactor vessel, which collectively define a nuclear reactor containment arrangement. The annular ring seal comprises an annular ring plate having an outer peripheral surface affixed to the containment wall and an inner peripheral surface proximate the reactor vessel; and a flexure member having an annular base plate, which sealingly engages and is affixed to the annular ring plate near the inner peripheral surface thereof, and having a leg which is joined to and extends upwardly from the annular base plate and which is affixed to the peripheral wall of the reaction vessel to thereby seal the annular thermal expansion gap.

Abstract: A control system for a trip coil in a switchgear mechanism which controls the supply of power to a process control device and ensures de-energization of the trip coil shortly after the trip coil is energized. A transformer is supplied with power by the switchgear and outputs reduced power to a rectifier which is connected to the trip coil via a trip activation device. The output of the rectifier can be monitored to determine the ability of the control system to activate the trip coil and the condition of the power supplied to the process control device.

Abstract: An alpha recoil ion-implantation method and apparatus are described which use an alpha-emitting source that is a radioactive parent of the daughter isotope of interest to implant into a suitable substrate the recoil daughter ions resulting from alpha decay of the parent. For example, a .sup.241 Am source in thin layer form is placed next to a substrate such as a solid state track recorder in a vacuum which houses an assembly for rotating opposing disks receiving the alpha-emitting source and the substrate, respectively. Each alpha decay of .sup.241 Am results in a .sup.237 Np ion with enough recoil energy to be implanted into the substrate. Fissionable deposits of .sup.239 Pu, .sup.235 U, and .sup.238 U can also be made by this method and apparatus.

Abstract: A method is described for correcting for effect of isotope burn-in in fission neutron dosimeters. Two quantities are measured in order to quantify the "burn-in" contribution, namely P.sub.Z',A', the amount of (Z', A') isotope that is burned-in, and F.sub.Z', A', the fissions per unit volume produced in the (Z', A') isotope. To measure P.sub.Z', A', two solid state track recorder fission deposits are prepared from the very same material that comprises the fission neutron dosimeter, and the mass and mass density are measured. One of these deposits is exposed along with the fission neutron dosimeter, whereas the second deposit is subsequently used for observation of background. P.sub.Z', A' is then determined by conducting a second irradiation, wherein both the irradiated and unirradiated fission deposits are used in solid state track recorder dosimeters for observation of the absolute number of fissions per unit volume. The difference between the latter determines P.sub.

Abstract: A shield panel for use in a nuclear reactor including a reactor vessel susceptible to embrittlement when bombarded with high energy neutrons and a nuclear reactor core mounted within the reactor vessel, the reactor vessel having a longitudinal axis and an inner surface surrounding the longitudinal axis, and the nuclear core emitting high energy neutrons which impinge on the inner surface of the reactor vessel. The shield panel includes a canister which contains a completely enclosed interior space and which is mountable between the inner surface of the reactor vessel and the nuclear core in a region wherein the reactor vessel is susceptible to a higher rate of embrittlement than the remaining portion of the vessel when bombarded with high energy neutrons emitted from the nuclear core, and a substance consisting essentially of a heavy metal and hydrogen filling the interior space of the canister.

Abstract: A chemical reactor vessel is provided with a plurality of tubes filled with a heat exchange fluid. The tubes are disposed in a heat exchange relationship with the reactor contents and are coupled via pressure sensitive rupture discs and a header to a reservoir. Upon overheating of the reactor contents, excess heat is absorbed by the heat exchange fluid which boils off at a predetermined vaporization temperature and vapor pressure to rupture the discs and thereby establish fluid communication between the tubes and a heat exchange fluid contained in the reservoir, and thereby maintaining the reactor contents at a preselected safe temperature.

Abstract: Components and systems which impact technical specifications (tech specs) in a nuclear power plant are modeled in a set of cascading operability trees which represent the various combinations of component, system and parameter statuses which can result in non-compliance with the tech specs. Cutsets for the operability trees are entered into a cutset table in the data base of a digital computer which tracks the effect of a selected event up through the trees by repetitively searching the cutset table using the top event activated by the selected event as the selected event for the next search, until an activated top event is reached which is not entered in the cutset table as an event. A separate cutset evaluation table is used to assure that all the members of a multiple event cutset have been activated before the associated top event is activated.

Abstract: Excessive primary cooldown and start up of the auxiliary feedwater system in a pressurized water reactor (PWR) following a reactor trip are avoided by switching to primary coolant T.sub.avg programmed, main feedwater flow control in place of normal level programmed control. The Low T.sub.avg set point at which the main feedwater isolation valves are closed is lowered below the no load T.sub.avg temperature set point and the flow rate is decreased gradually to zero at a T.sub.avg between these two set points. In addition, the low-low level set point at which the auxiliary feedwater system is started is lowered if possible, and/or the level signal is filtered, or the start signal delayed, to increase the margin to the low-low set point.

Abstract: A cartridge for the permanent storage and disposal of radioactive particulate waste composed of a liquid impervious casing enclosing a waste storage region provided with a ferromagnetic matrix made of steel wool, together with inlet and outlet conduits suitably associated with the waste storage region to enable a liquid containing such waste material to be conducted through the matrix while the particulate waste is adhered thereto under the influence of a magnetic field and the remaining liquid filtrate is expelled from the cartridge, and to then permit an encapsulating material, such as a resin-catalyst mixture, to be introduced into the waste storage region to completely fill that region.

Abstract: A method and apparatus for locking the wedges used in a dynamoelectric machine having a radically ventilated rotor keys each wedge to its respective damper bar. By inserting a solid key in a selected keyway proximate to a point midway along the length of the rotor, and inserting split keys elsewhere, accumulated axial migration of the wedges relative to their respective damper bar is limited thereby ensuring adequate ventilation through the radically extending ducts.