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: 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: 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: 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 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 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.