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 multi-star fiber optic network includes a series of two or more passive transmission stars disposed in different local areas, each star serving terminal devices in its local area. A pair of repeaters between each successive star of the series receive optical signals on one channel and transmit the information on at least one different channel, thereby avoiding repeated reflections between successive stars. Wavelength multiplexing, frequency modulation, and amplitude modulation techniques may be employed to provide the different channels, one of which may be a baseband channel. Modified amplitude techniques may be employed to provide directional enable or inhibit signals on different channels.

Abstract: A T-connection fiber-optic repeater is used in a fiber-optic network wherein the repeaters are connected by optical fibers to other repeaters and the repeaters are also connected to stars, in such a manner that an optical signal can move from repeater to repeater without having to traverse a star. Each repeater includes optical receivers for receiving optical signals from the adjacent repeaters and from a nearby star and optical transmitters for emitting optical signals to the adjacent repeaters and the nearby star. Since signal reflections from the nearby star arrive almost immediately after signals from the adjacent repeaters, an inhibit circuit is used to gate signals from the nearby star when signals are being received from either of the adjacent repeaters. This avoids instability arising from repeated signal reflection without imposing a significant time delay as reflected signals propagate through long lengths of fiber.

Abstract: A self-preparing electrode, suitable for EEG mapping, includes a metallic cylinder separated by a dielectric cylinder from a socket for a probe assembly. The probe assembly is preferably a tulip probe removably held by the socket which is connectable to an inner conductor of a coaxial cable. The metallic cylinder includes a cavity into which the tip of the tulip probe is partially depressed when the probe assembly and shell are placed on the skin of a patient. The tip of the tulip probe has multiple points which penetrate the dead skin layer and make electrical contact with the blood-rich skin layer of the patient. The electrode is held in place by straps attached to the shell of the electrode.

Abstract: An expandable antivibration bar for use in stabilizing the U-bend portion of heat transfer tubes in a pressurized water reactor steam generator comprises two adjustable rods connected together by an arcuate connector. The two adjustable rods preferably comprise two mating rod sections having complementary angular sliding surfaces thereon, with means provided to move the rod sections relative to each other along the sliding surfaces so as to expand the rods from a first mated cross-sectional width to a second larger cross-sectional width. The ends of the rod sections have means for aligning the two rod sections and maintaining them in alignment during expansion.

Abstract: An installation composed of a plurality of machines disposed adjacent a common work space delimited by a boundary surface, each machine being associated with a respective portion of the boundary surface and having a work-performing member movable into and out of the work space through the associated boundary surface portion, and an optical monitoring system composed of a plurality of optical monitoring assemblies each associated with a respective machine.

Abstract: Electric power is produced in an electric power generating combustion turbine using a biogas as fuel thereto, where a biogas, leaving a biomass gasification system at an elevated temperature of 650.degree.-875.degree. C. and containing tars, is partially cooled by injection of a spray of water thereto to a lower temperature of about 260.degree.-555.degree. but above that which would condense tars. The partially cooled biogas stream is then filtered to remove solid particulate matter therefrom and is directly charged as fuel to the electric power producing combustion turbine for the production of electric power.

Abstract: On-line, real time monitoring of core-wide and local power in an advanced pressurized water reactor is provided by a system having four channel sets of fixed incore nuclear detector strings distributed in fuel assemblies across the core in a pattern which produces a uniquely identifiable detector response to rod movement even with one channel set out of service. Separate signal processors for each channel generate totally independent core-wide overpower protection signals and exchange detector responses through fiber optic data links for local power monitoring. The local power density at each detector level for any desired point across the core is determined by fitting a surface spline function to the detector responses adjusted to eliminate the local effects of rod movement from a reference condition, interpolation of the fitting function, and factoring back in the local effects of rod movement.

Abstract: A closure system for a storage cask containing spent nuclear fuel has redundant mechanical seals to temporarily close the cask during development, testing, and refinement thereof, when it is occasionally necessary to open the cask, and redundant welded seals to supplement the mechanical seals when development is completed and the cask is permanently sealed during long-term storage. The closure system includes a primary cover which cooperates with an O-ring to provide a mechanical seal and which includes a canopy element that can be welded to the cask base element if a permanent seal is desired. The closure system also includes a secondary cover which cooperates with an additional O-ring to provide an additional mechanical seal and which is configured to receive an additional canopy element in the event that an additional welded seal is desired. The closure system permits the cask to be developed, tested, and refined using the same closure system that will be installed during actual use.

Abstract: Apparatus (10) for imparting protecting compressive stresses to the inside surfaces of a U-shaped heat exchanger tube (12) in order to eliminate or substantially reduce residual tensile stresses within the U-bend region of the U-shaped heat exchanger tube (12) as a result of the fabrication of the U-shaped tube (12) under cold bending techniques comprises a high-speed rotary drive motor (22), flexible drive shafts (28, 30) extending throughout the axial length of the U-bend region of the U-shaped tube (12), and shot-peening flaps (32) having tungsten-carbide shot particles secured thereto. A plurality of epicyclic gear trains (26) are axially spaced along the flexible drive shafts (28, 30) so as to cause the shot-peening flaps (32) to orbit about the interior surface of the U-bend region of the U-shaped tube (12) simultaneously with the high-speed rotary drive of the flexible drive shafts (28, 30).

Abstract: A self-preparing subkeratinous probe for electroencephalographic measurement includes a spring body which applies a penetrating force to a plow which parts hair and scrapes through a dead keratinous layer of skin to a bloodrich epidermis layer while the probe is being positioned on the head without causing bleeding. The plow includes tabs which form a gap for parting the hair and scraping the skin. The probe also includes an electrolyte tube which can be used to apply electrolyte solution to the skin and plow after it is positioned.

Abstract: A process for cleaning out deposits collected in the restricted areas of the secondary side of a steam generator of a nuclear power plant system, where the concentration of an aqueous organic cleaning agent solution is increased in the restricted areas, relative to the remainder of the solution. The solution is heated, at an initial pressure which prevents boiling of the solution, and the pressure is reduced to effect localized flashing and boiling of the solution in the restricted areas. After a period of time, the pressure is increased and the cleaning agent solution, containing solubilized deposits, is withdrawn from the secondary side of the steam generator. The heating temperature and pressure will vary depending upon the type of deposit to be removed, either ferrous-type or copper-type deposits.

Abstract: A method and apparatus for producing a display of eddy current test data from signals produced by an eddy current detector which is supplied with an alternating current signal composed of alternating currents at several different frequencies, the detector signals including a respective signal associated with each current frequency and varying in amplitude and in phase relative to its associated alternating current as the detector is displaced relative to a test body.

Abstract: A method for temperature compensating a position indicator which includes a sensor for producing an output signal whose magnitude corresponds to the position of an element that is linearly movable between first and second positions and which is subject to changes in temperature within a given temperature range and wherein the output signal of the sensor contains a temperature variable offset component and the rate of increase of the output signal as the element moves from the first to the second position fluctuates with changes in temperature.

Abstract: A phase locked loop stepper motor controlled light chopper for providing a specific pattern reversal rate. The stepper motor controlled light chopper includes a phase comparator for comparing the phase of a reference signal to the phase of a comparison signal; a RC low pass filter for filtering the output of the phase comparator; a voltage controlled oscillator having a frequency varying in response to the output of the RC filter. The chopper also includes a binary counter for generating count signals responsive to the frequency of the voltage controlled oscillator; a divide by 10 circuit counting one of the outputs of the binary counter and providing the comparison signal. The light chopper also includes a memory circuit for storing an eight state four bit gray code for driving a four phase stepper motor as a chopper wheel in a specified pattern mounted on a drive shaft.

Abstract: A reactor vessel stud cleaning machine for cleaning reactor studs. The stud is supported horizontally by a pair of roller carriage assemblies inside of a closed chamber. At least one roller carriage assembly has rollers driven by a stud drive motor which cause the stud to rotate. As the stud rotates, a spray nozzle traverses the length of the stud spraying a mixture of high pressure water and abrasive onto the stud. The spent water and abrasive is drained from the enclosure and pumped through a separator funnel and filter bank to remove solids. The filtered water is returned to a supply tank for reuse. The stud rotation speed and spray nozzle traverse speed the variable as in the water pressure and rate of abrasive injection.

Abstract: Coils placed at spaced locations along the path of an axially movable magnetically permeable and/or electrically conductive rod, which changes the impedance of each coil as it passes through, are connected in sets with each set comprising two series connected groups of equal numbers of parallel connected, non-adjacent coils energized by an a-c source. The voltage at the common node of each set of coils, which fluctuates as equal and unequal numbers of coils in the two groups in a given set are penetrated by the end of the rod, is compared with the voltage at the common node of a pair of series connected resistors, also energized by the a-c source, to generate one digit of an unambiguous, multi-digit, digital rod position signal. Since only one signal wire to the remote electronics is required for each set of coils, and since they only carry a voltage signal, the required wiring is minimized.

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 ventilation system for a storage or transfer canal for radioactive materials comprises a series of air emitting nozzles spaced along one side of and above the upper surface of the canal to produce an air curtain completely covering the surface of the canal, and a series of exhaust hood openings on the opposite side of the canal to capture and exhaust the air in the air curtain and a part of the air above the air curtain.

Abstract: A method of testing the operability of check valves having a pivotal closure disk wherein a check valve is provided having a valve body and first sealing member of nonmagnetic material and a pivotal closure disk and second sealing member of magnetic material, and a magnetic field is applied in a direction which causes the closure disk to move away from the first sealing member. The attraction between the magnetic field generator and the closure disk is measured to determine the relative position of the closure disk to the first sealing member and thus the operability of the valve.