Abstract: The water flow circuit for a heat recovery steam generator is a hybrid system which combines a circulating drum type circuit and a once-through circuit. A low pressure evaporator is designed for natural or forced circulation and a high pressure evaporator is designed for once-through flow. Orifices may be located in the inlet of the evaporator tubes for flow stability and an intermediate header between the evaporator and high pressure superheater improves stability, minimizes orifice pressure drop and equalizes pressure losses between evaporator tubes.

Abstract: The flue gas temperature coming from an air preheater to a particulate collection device such as an electrostatic precipitation or fabric filter is reduced to improve the operation of the particulate collection device. This may be done by reducing the exit flue gas temperature from the air preheater or reducing the temperature after exiting. In one embodiment, air in excess of that needed for combustion is passed through the air preheater with the heated excess air either being dumped or used for a variety of purposes in the plant. A particular embodiment involves segmenting the air outlet side of a rotary regenerative air preheater and withdrawing the excess air from the segment where the dust loading is the lowest. Further, additional cooling of the flue gas can be provided by reducing the quantity of primary air that typically bypasses the air preheater and then providing other ways to control the primary air temperature to the pulverizers.

Abstract: Compliance with administrative limits on cumulative exposure of control rod groups in the reactor core, is monitored by computing the incremental effective exposure for each group commensurate with core power, for each time increment at which each group is within the position range where an administrative limit is imposed. The increments of effective exposures for each group are accumulated, and the accumulated effective exposure for each group is compared with the administrative limit to each group. This comparison is then displayed to the reactor operator, preferably using either a "rolling wheel" or "sliding bar" format.

Abstract: A minimum recirculation flame control (MRFC) solid fuel nozzle tip (12) that is suited to being cooperatively associated with a pulverized solid fuel nozzle (34) of a firing system in a pulverized solid fuel-fired furnace (10). The MRFC solid fuel nozzle tip (12) includes a secondary air shroud (46), secondary air shroud support (50) operative for supporting the primary air shroud (48) relative to the secondary air shroud (46), and a splitter plate (52) mounted in supported relation within the primary air shroud (48).

Abstract: A method and apparatus for mitigating oscillatory pressure disturbances that result from venting steam from a nuclear reactor into a pressure suppression pool through a plurality of spargers is disclosed. The individual spargers are connected in series so that a time delay exists between first venting of noncondensable gas and steam from successive spargers. This time delay can be adjusted so that the pressure disturbances from successive spargers are out of phase, partially or wholly canceling one another. This cancellation of oscillatory pressure disturbances minimizes dynamic loads on the walls of the suppression pool and on structures submerged in the suppression pool.

Abstract: An arrangement for supporting a vane wheel assembly of a pulverizer bowl mill that is operative to effect therewith a reliable and accurate securement of a vane wheel assembly to the rotating grinding table of the pulverizer bowl mill.

Abstract: A deposit removal high pressure spray apparatus for removing heat conduction inhibiting deposits on U-tubes at the top of a shell and tube type of nuclear steam generator (10) tube bundle (16) by crawling along flanged outboard support beams (18) above the U-tubes bundle. The apparatus includes: a crawler (66) with motive means 68 for "inch worm" movement; a rotationally driven base 62 provides movement of the sprayhead to either side of the outboard support beam; a rotationally driven extension arm 60 on rotating base 62 has an elongated reciprocally driven elevator 58 thereon; and, a wrist 52 reversibly and rotatably driven by motor 54a sweeps sprayhead 52 with nozzles 56 to clean the top of the bundle 16 tube lanes of 90.degree., 45.degree. and 135.degree. efficiently.

Abstract: An energy-efficient grinding roll for employment in a pulverizer operative for effecting the pulverization of solid material therein. The energy-efficient grinding roll includes a body portion formed of a first type of material, an external surface formed of a second type of material, and tread-like means of preestablished dimensions and preestablished spacing provide on the external surface such that the energy-efficient grinding roll is capable of achieving as much as a 15% reduction in the energy required to pulverize solid material when compared with the use of standard grinding rolls.

Abstract: A buckstay system of an associated furnace having a combustion cavity with a front waterwall, a rear waterwall, and opposed left and right side waterwalls joining the front and rear waterwalls and where the waterwalls are arranged in a generally square pattern about the cavity. The cavity has four corners and each buckstay an attachment module welded to each end, each attachment module includes first and second planar plates. The first and second planar plates are disposed in side abutting relationship to the web of the buckstay and extend beyond the end of the buckstay, each of the first and second plates have coaxial pivot holes disposed in a part thereof that extends beyond the end of the buckstay. The planar plates in the attachment module may be rectangular. Or have a notch or recess for clearance.

Abstract: The present invention relates to a method for controlling thermal processes, whereby measuring devices measure at least two process parameters at least once within a time interval in which a parameter change occurs that is not negligible for the process sequence, the recorded parameters are fed into a control unit, and the control unit regulates the process parameters in the thermal process by means of quantities obtained from the measurements of process parameters.

Abstract: A feedwater control system for a pressurized water steam generating system, and a method for using such, includes a steam generator, at least one feedwater pump which receives an output signal from the feedwater control system, an economizer feedwater control valve which receives the output signal and automatically controls flow of feedwater to the steam generator when a power level of the feedwater control system is at a first predetermined range, preferably between about 10 and 100%, and a downcomer feedwater control valve which receives the output signal and automatically controls the flow of feedwater to the steam generator when the power level is at a second predetermined range, preferably between 0 and about 10%. A first input signal is provided, determined by the feedwater flow of the steam generator, along with a second input signal, determined by the steam flow of the steam generator, and a third input signal, determined by the level of the steam generator.

Abstract: A heat recovery generator has a housing defining a horizontally oriented exhaust gas stream. The exhaust gas stream passes through a first heat recovery unit having horizontally oriented heat transfer tubes and forced circulation of a heat transfer fluid therethrough. The exhaust gas stream then is passed through an air pollution control assembly having a catalyst for reduction of exhaust emissions. The exhaust gas stream is subsequently passed through a second heat recovery steam generator having vertically oriented heat transfer tubes and natural circulation therethrough.

Abstract: A digital plant protection system for use in nuclear power plants of the pressurized water type includes cross-connected sensed-parameter processing channels that provide a suitably conditioned digital value to a digital comparator that tests the conditional digital value against a predetermined value to determine whether or not the sensed parameter has been exceeded. A comparator is associated with each of the plural channels and receives a separate measurement of the sensed parameter for each channel. If a sensed-parameter is determined to be out-of-specification by 2 of 4 or more channels, a `trip` signal is generated to effect remedial action.

Abstract: A multi-lift tool and method for moving control rod assemblies in a nuclear reactor. The multi-lift tool comprises a frame having an upper end and a lower end. A control rod grapple is supported by the frame for engaging a lifting handle of a control rod. The control rod grapple is movable along a length of the frame for raising and lowering the control rod relative to the frame. A fuel support piece grapple is secured to the lower end of the frame for engaging and lifting a fuel support piece together with the control rod. A blade guide grapple is secured to the upper end of the frame for engaging and lifting a blade guide together with the fuel support piece and the control rod. An unlatching grapple is supported near the lower end of the frame for engaging and lifting an unlatching handle of the control rod. The unlatching grapple is movable along a length of a lower portion of the frame for raising the unlatching handle of the control rod relative to the frame.

Abstract: There is provided a circulating fluidized bed steam generator (CFB) having an improved structural support system and an improved combined hot solids-gas separator for separating gas and solids from a combined gas-solids stream. The combined hot solids-gas separator is in the form of a cyclone assembly having a plurality of wall portions forming a separation chamber and an inlet for passage of a combined gas-solids stream into the separation chamber. The lowermost extent of the inlet forms a threshold over which the combined gas-solids stream flows in entering the separation chamber. The separation chamber is operable to separate the combined gas-solids stream into a predominantly gas exit stream and a predominantly solids exit stream in a manner by which separated out solids to be discharged from the separation chamber via the predominantly solids exit stream are collected within the separation chamber at a location lower than the inlet.

Abstract: A method is provided which refurbishes a Rankine cycle vapor generator initially having a plurality of Rankine heaters for supporting a Rankine cycle subsystem. The method removes at least one of the Rankine heaters, and replaces the at least one removed Rankine heater with a non-Rankine heater for a Kalina cycle subsystem. The vapor generator comprises a first plurality of tubes for receiving a first working fluid, and a second plurality of tubes for receiving a second working fluid. The first plurality of tubes are directed along a first path exposed to heat from a heat source to increase the temperature of the first working fluid within the first plurality of tubes. The second plurality of tubes are directed along a second path exposed to heat from the heat source to increase the temperature of the second working fluid within the second plurality of tubes.

Abstract: A tube loading apparatus and method for tensile strength and leak testing an elongated, hollow tube such as a steam generator heat transfer tube of a steam generator plant. The apparatus may be used to determine the axial or compressive load placed on a hollow tube.

Abstract: A pulverizer shaft rotation support assembly includes a rolling element sub-assembly for rotationally supporting the shaft of a pulverizer of a bowl mill of the type which is operative for pulverizing material such as coal into smaller particles, and includes a separator body having a bore, a rotating shaft supported within the bore, and a grinding table supported on the shaft. The rolling element sub-assembly includes an inner race secured to the shaft at a first shaft location, an outer race and a plurality of cylindrical bearings for rolling movement along and intermediate the inner and outer races. The pulverizer shaft rotational support assembly also includes an annular cutout in a gearbox housing structure for radially limiting the outer race while permitting axial movement thereof.

Abstract: A feedwater control system and method for a pressurized water reactor steam generating system having first and second output signals. The first output signal is determined by first and second input signals, and, when combined with a third input signal automatically controls at least one feedwater pump and first designated valves which regulate water flow from the one or more feedwater pumps to a steam generator when a steam generator steam load and reactor are operating at a first predetermined power level. The first input signal is determined by a downcomer feedwater flow differential pressure. The second input signal is determined by a reactor power level. The third input signal is determined by a steam generator level. The second output signal, determined by a steam generator water level, automatically controls at least one startup feedwater control valve when the steam generator steam load and the reactor are operating at a second predetermined power level.

Abstract: A system and method of managing, storing, and accessing cross references between related kinds of sub-record information in a computerized engineering database. A generic cross reference table which contains all the cross reference links for all the data items in all the data tables of the engineering database, is provided. Each link in the generic cross reference table is constituted by two records (1) a forward record with a specified link from a data item in a first data table to a record or a data item in a second data table, plus (2) a reverse record (partner record) with the link from the data item in the second data table to the record or an item in the first data table. Preferably, the link record in the cross reference table contains a link type value selected from a set of pre-defined link types for the pair of link points, comments associated with the link at the time of creation, and other link-creation information such as the identification of the user who created the link.