摘要:
Method for loosening and removing sludge and debris from the vessel (5) of a heat exchanger (1), such as the secondary side (5) of a nuclear steam generator (1). The method generally comprises the steps of providing a sufficient volume of a liquid, such as water, into the steam generator (1) so that the lower portion which includes the tubesheet (7) is submerged, and then generating a succession of pressure pulses within the water from one or more pressure pulse generators (60a, 60b) wherein each pressure pulse creates shock waves that exert momentary forces throughout the submerged portion of the generator (1) of a magnitude sufficient to loosen the sludge and debris, but safely below the yield and fatigue limits of the heat exchanger tubes (22) and other components within the generator. The water is preferably circulated through a demineralizer (157) in order to remove ionic species therefrom.
摘要:
Apparatus for loosening and removing sludge and other impurities from the interior of a heat exchanger vessel (5) which may be the secondary side (5) of a nuclear steam generator (1). The apparatus generally comprises a nozzle (111) having a first end that is detachably mountable into an access opening (53a, 53b) such as a sludge lance port (53a, 53b) in the secondary side of the generator, and a second end that extends into the interior of the secondary side (5) at a downward angle relative to the tubesheet (7) in the vessel (5) for minimizing the stresses applied to the heat exchanger tubes (22), and for uniformly reflecting the pulse back up toward the upper portions of the secondary side (5). The apparatus preferably further comprises a recirculation system (114) for purifying the water within the generator (1) while a pulse generator (60a, 60b) emits a succession of sludge and debris loosening pulses therein. An array of inlet and suction tubes (121a, 121b) are further provided so that the sludge and debris may be removed.
摘要:
Apparatus for loosening and removing sludge and other impurities from the interior of a heat exchanger vessel (5) which may be the secondary side (5) of a nuclear steam generator (1). The apparatus generally comprises a nozzle (111) having a first end that is detachably mountable into an access opening (53a, 53b) such as a sludge lance port (53a, 53b) in the secondary side (5) of the generator, and a second end (113) that extends into the interior of the secondary side (5) at a downward angle relative to the tubesheet (7) in the vessel (5) for minimizing the stresses applied to the heat exchanger tubes (22), and for uniformly reflecting the pulse back up toward the upper portions of the secondary side (5). The apparatus preferably further comprises a recirculation system (114) for purifying the water within the generator (1) while a pulse generator (60a, 60b) emits a succession of sludge and debris loosening pulses therein. An array of inlet and suction tubes (121a, 121b) are further provided so that the sludge and debris may be removed.
摘要:
Method for removing sludge and deposits (32) from the interior of a heat exchanger vessel (1). The method includes the steps of filling the interior of the secondary side (5) of the heat exchanger vessel (1) with an aqueous solution of a cleaning agent formed from at least one of the group consisting of surfactants, dispersants, thixotropes and flotation agents, recirculating the aqueous solution within the secondary side (5) while simultaneously filtering it to remove sludge and deposits (32) entrained within the solution, and draining the aqueous solution from the secondary side (5) while continuously introducing a succession of pressurized pulses of gas into the solution during the filling, recirculation and draining steps in order to create shock waves in the solution which loosen and fluidize sludge and deposits (32) present within the secondary side (5).
摘要:
A system (70) and a method for removing sludge and debris from the interior of the secondary side (5) of a nuclear steam generator (1). The method comprises the steps of introducing a sufficient amount of water in the secondary side (5) to submerge at least the tubesheet (7), generating a succession of shock waves in the water by means of pulses of pressurized gas to create shock waves that loosen the sludge and debris, and vertically flushing the interior of the secondary side (5) by suctioning water off from the bottom portion of the steam generator (1) while simultaneously forcefully spraying water from the top portion of the generator (1) over the bundle (20) of heat exchanger tubes (22) in order to remove the sludge and debris loosened by the shock waves. To conserve the water used in the flushing operation, the water that is suctioned off from the bottom portion of the steam generator (1) is filtered and deionized and reintroduced through hoses (128a, 128b) at the top portion of the generator (1) which forcefully directs water downwardly through the bundle (20) of heat exchanger tubes (22) and against the tubesheet (7). The invention greatly enhances the effectiveness of pressure pulse, water slap and water cannon cleaning methods in the secondary sides (5) of nuclear steam generators (1).
摘要:
An improved method for removing sludge and corrosion products (32) from the interior of a heat exchanger vessel (1), such as a nuclear steam generator (1), which comprises the steps of generating a series of pressure pulses within a liquid chelate-containing chemical cleaning agent after the agent has been introduced into the interior of the vessel (1) to create shock waves in the liquid for dislodging, dissolving and fluidizing sludge and corrosion products (32). The use of pressure pulsing in combination with chemical cleaning substantially diminishes the chances that the chemical cleaning agents will induce further unwanted corrosion in the steam generator (1) by allowing the agent to be introduced and recirculated within the generator (1) at a lower temperature, or by allowing the use of a lower concentration of corrosion-inducing chelates, or by reducing the residence time required for the cleaning agent to clean the interior of the generator (1) than would otherwise be required if only the cleaning action of the chemical cleaning agents were relied upon.
摘要:
A system (70) and a method for removing sludge and debris from the interior of the secondary side (5) of a nuclear steam generator (1). The method comprises the steps of introducing a sufficient amount of water in the secondary side (5) to submerge at least the tubesheet (7), generating a succession of shock waves in the water by means of pulses of pressurized gas to create shock waves that loosen the sludge and debris, and vertically flushing the interior of the secondary side (5) by suctioning water off from the bottom portion of the steam generator (1) while simultaneously forcefully spraying water from the top portion of the generator (1) over the bundle (20) of heat exchanger tubes (22) in order to remove the sludge and debris loosened by the shock waves. To conserve the water used in the flushing operation, the water that is suctioned off from the bottom portion of the steam generator (1) is filtered and deionized and reintroduced through hoses (128a, 128b) at the top portion of the generator (1) which forcefully directs water downwardly through the bundle (20) of heat exchanger tubes (22) and against the tubesheet (7). The invention greatly enhances the effectiveness of pressure pulse, water slap and water cannon cleaning methods in the secondary sides (5) of nuclear steam generators (1).