Patent Number: 043205283
Section: claims

1. In the art of maintaining a steam generator for a nuclear power plant in which the steam generator is characterized by an enclosed tank containing a plurality of heat exchanger tubes and a plurality of support plates arranged transverse to and sequentially spaced along the longitudinal axis of the tubes and forming junctions therewith, where crevices exist between the heat exchanger tubes and the support plates at the site of the junctions, the junctions being thereby arranged in a series of groups, and also containing an outer shell and a metal wrapper inside the tank which envelops the plurality of tubes and support plates, and wherein magnetite tends to build up within the crevices at the junctions over a period of time, the process of removing the magnetite from the crevices and the junctions while the heat exchanger tubes and support plates remain in their operative position inside the steam generator, comprising the steps of: a. selecting a chemical solvent which when heated to a temperature between 120 degrees Fahrenheit and 220 degrees Fahrenheit dissolves magnetite exposed to fresh chemicals at a rate equal to or greater than about 1.0 inch per 24 hours;  b. adding a metal corrosion inhibitor to said chemical solvent;  c. at least partially filling the tank with said chemical solvent, so as to establish an initial level which is only a few inches above the level of the uppermost group of junctions and their uppermost group of crevices;  d. selecting a plurality of sonic transducers wherein each sonic transducer has a power output greater than about 0.2 watts per square centimeter at room temperature;  e. placing said plurality of sonic transducers at a level which is below the surface of said chemical solvent, substantially in the plane of said uppermost group of junctions and uppermost group of crevices and in spaced locations around the circumference of and in contact with said metal wrapper;  f. running a hot fluid through said heat exchanger tubes so that the chemical solvent in the region adjacent said junctions and crevices reaches a temperature between 120 degrees Fahrenheit and 220 degrees Fahrenheit;  g. activating said sonic transducers to a frequency in the range of about 2 KHZ to 200 KHZ so that sonic energy is transmitted through said chemical solvent to said junctions and into and laterally of said crevices whereby cavitation induced at said junctions and at said crevices by said sonic energy cooperates with said chemical solvent so as to enhance and accelerate the removal of the magnetite from said junctions and crevices;  h. continuing the cooperative action of said hot chemical solvent and said transducers upon said uppermost group of junctions and crevices until the magnetite is removed from the junctions and crevices;  i. maintaining said chemical solvent at a temperature between 120 degrees Fahrenheit and 220 degrees Fahrenheit;  j. then lowering the level of said chemical solvent to a height which is only a few inches above the next group of junctions and crevices from which magnetite is to be removed, lowering said plurality of transducers to a corresponding lower location on said metal wrapper in a plane substantially in alignment with said next group of junctions and crevices, and again applying said cooperative effort between said hot chemical solvent and said transducers until the magnetite is removed from said next group of junctions and next group of crevices; and  k. continuing in this fashion at the level of each successive group of junctions and crevices until all of said junctions and crevices have been cleaned.  a. selecting a chemical solvent which when heated to a temperature between 120 degrees Fahrenheit and 220 degrees Fahrenheit dissolves magnetite exposed to fresh chemicals at a rate equal to or greater than about 1.0 inch per 24 hours;  b. adding a metal corrosion inhibitor to said chemical solvent;  c. at least partially filling the tank with said chemical solvent, so as to establish an initial level which is only a few inches above the level of the lowermost group of junctions and their lowermost group of crevices;  d. selecting a plurality of sonic transducers wherein each sonic transducer has a power output greater than about 0.2 watts per square centimeter at room temperature;  e. placing said plurality of sonic transducers at a level which is below the surface of said chemical solvent, substantially in the plane of said lowermost group of junctions and lowermost group of crevices and in spaced locations around the circumference of and in contact with said metal wrapper;  f. running a hot fluid through said heat exchanger tubes so that the chemical solvent in the region adjacent said junctions and crevices reaches a temperature between 120 degrees Fahrenheit and 220 degrees Farenheit;  g. activating said sonic transducers to a frequency in the range of about 2 KHZ to 200 KHZ so that sonic energy is transmitted through said chemical solvent to said junctions and into and laterally of said crevices whereby cavitation induced at said junctions and at said crevices by said sonic energy cooperates with said chemical solvent so as to enhance and accelerate the removal of the magnetite from said junctions and crevices;  h. continuing the cooperative action of said hot chemical solvent and said transducers upon said lowermost group of junctions and crevices until the magnetite is removed from the junctions and crevices;  i. maintaining said chemical solvent at a temperature between 120 degrees Fahrenheit and 220 degrees Fahrenheit;  j. then raising the level of said chemical solvent to a height which is only a few inches above the next group of junctions and crevices from which magnetite is to be removed, raising said plurality of transducers to a corresponding higher location on said metal wrapper in a plane substantially in alignment with said next group of junctions and crevices, and again applying said cooperative effort between said hot chemical solvent and said transducers until the magnetite is removed from said next group of junctions and next group of crevices; and  k. continuing in this fashion at the level of each successive group of junctions and crevices until all of said junctions and crevices have been cleaned.  a. selecting a chemical solvent which when heated to a temperature between 120 degrees Fahrenheit and 220 degrees Fahrenheit dissolves magnetite exposed to fresh chemicals at a rate equal to or greater than about 1.0 inch per 24 hours;  b. adding a metal corrosion inhibitor to said chemical solvent;  c. at least partially filling the tank with said chemical solvent, so as to establish an initial level which is only a few inches above the level of the uppermost group of junctions and their uppermost group of crevices;  d. selecting a plurality of sonic transducers wherein each sonic transducer has a power output greater than about 0.2 watts per square centimeter at room temperature;  e. placing said plurality of sonic transducers at a level which is substantially in the plane of each of said groups of junctions and in spaced locations around the circumference of and in contact with said metal wrapper;  f. running a hot fluid through said heat exchanger tubes so that the chemical solvent in the region adjacent said junctions and crevices reaches a temperature between 120 degrees Fahrenheit and 220 degrees Fahrenheit;  g. activating all the transducers simultaneously at each level substantially in the plane of each group of junctions and each group of crevices to a frequency in the range of about 2 KHZ to 200 KHZ so that sonic energy is transmitted through said chemical solvent to each group of junctions and into and laterally of each group of crevices whereby cavitation induced at each group of junctions and each group of crevices cooperates with said chemical solvent so as to enhance and accelerate the removal of the magnetite from the all of the junctions and crevices;  h. continuing the cooperative action of said hot chemical solvent and said transducers upon each group of junctions and crevices until the magnetite is removed from all of the junctions and all of the crevices.  a. selecting a chemical solvent which when heated to a temperature between 120 degrees Fahrenheit and 220 degrees Fahrenheit dissolves magnetite exposed to fresh chemicals at a rate equal to or greater than about 1.0 inch per 24 hours;  b. adding a metal corrosion inhibitor to said chemical solvent;  c. selecting a plurality of sonic transducers wherein each sonic transducer has a power output greater than about 0.2 watts per square centimeter at room temperature;  d. placing said plurality of sonic transducers at a level substantially in the plane of the uppermost group of junctions and uppermost group of crevices and in spaced locations around the circumference of and in contact with said metal wrapper;  e. heating said chemical solvent to a temperature between 120 degrees Fahrenheit and 220 degrees Fahrenheit at a location outside of said steam generator;  f. at least partially filling the tank with said heated chemical solvent, so as to establish an initial level which is only a few inches above the level of the uppermost group of junctions and their uppermost group of crevices;  g. activating said sonic transducers to a frequency in the range of about 2 KHZ to 200 KHZ so that sonic energy is transmitted through said chemical solvent to said junctions and into and laterally of said crevices whereby cavitation induced at said junctions and at said crevices by said sonic energy cooperates with said chemical solvent so as to enhance and accelerate the removal of magnetite from said junctions and crevices;  h. continuing the cooperative action of said hot chemical solvent and said transducers upon said uppermost group of junctions and crevices until the magnetite is removed from the junctions and crevices;  i. maintaining said chemical solvent at a temperature between 120 degrees Fahrenheit and 220 degrees Fahrenheit;  j. then lowering the level of said chemical solvent to a height which is only a few inches above the next group of junctions and crevices from which magnetite is to be removed, lowering said plurality of transducers to a corresponding lower location on said metal wrapper in a plane substantially in alignment with said next group of junctions and crevices, and again applying said cooperative effort between said hot chemical solvent and said transducers until the magnetite is removed from said next group of junctions and next group of crevices; and  k. continuing in this fashion at the level of each successive group of junctions and crevices until all of said junctions and crevices have been cleaned.  a. selecting a chemical solvent which when heated to a temperature between 120 degrees Fahrenheit and 220 degrees Fahrenheit dissolves magnetite exposed to fresh chemicals at a rate equal to or greater than about 1.0 inch per 24 hours;  b. adding a metal corrosion inhibitor to said chemical solvent;  c. selecting a plurality of sonic transducers wherein each sonic transducer has a power output greater than about 0.2 watts per square centimeter at room temperature;  d. placing said plurality of sonic transducers at a level substantially in the plane of the lowermost group of junctions and lowermost group of crevices and in spaced locations around the circumference of and in contact with said metal wrapper;  e. heating said chemical solvent to a temperature between 120 degrees Fahrenheit and 220 degrees Fahrenheit at a location outside of said steam generator;  f. at least partially filling the tank with said heated chemical solvent, so as to establish an initial level which is only a few inches above the level of the lowermost group of junctions and their lowermost group of crevices;  g. activating said sonic transducers to a frequency in the range of about 2 KHZ to 200 KHZ so that sonic energy is transmitted through said chemical solvent to said junctions and into and laterally of said crevices whereby cavitation induced at said junctions and at said crevices by said sonic energy cooperates with said chemical solvent so as to enhance and accelerate the removal of the magnetite from said junctions and crevices;  h. continuing the cooperative action of said hot chemical solvent and said transducers upon said lowermost group of junctions and crevices until the magnetite is removed from the junctions and crevices;  i. maintaining said chemical solvent at a temperature between 120 degrees Fahrenheit and 220 degrees Fahrenheit;  j. then raising the level of said chemical solvent to a height which is only a few inches above the next group of junctions and crevices from which magnetite is to be removed, raising said plurality of transducers to a corresponding higher location on said metal wrapper in a plane substantially in alignment with said next group of junctions and crevices, and again applying said cooperative effort between said hot chemical solvent and said transducers until the magnetite is removed from said next group of junctions and next group of crevices; and  k. continuing in this fashion at the level of each successive group of junctions and crevices until all of said junctions and crevices have been cleaned.  a. selecting a chemical solvent which when heated to a temperature between 120 degrees Fahrenheit and 220 degrees Fahrenheit dissolves magnetite exposed to fresh chemicals at a rate equal to or greater than about 1.0 inch per 24 hours;  b. adding a metal corrosion inhibitor to said chemical solvent;  c. selecting a plurality of sonic transducers wherein each sonic transducer has a power output greater than about 0.2 watts per square centimeter at room temperature;  d. placing said plurality of sonic transducers at a level which is substantially in the plane of each of said groups of junctions and in spaced locations around the circumference of and in contact with said metal wrapper;  e. heating said chemical solvent to a temperature between 120 degrees Fahrenheit and 220 degrees Fahrenheit at a location outside of said steam generator;  f. at least partially filling the tank with said heated chemical solvent, so as to establish an initial level which is only a few inches above the level of the uppermost group of junctions and their uppermost group of crevices;  g. activating all the transducers simultaneously at each level substantially in the plane of each group of junctions and each group of crevices to a frequency in the range of about 2 KHZ to 200 KHZ so that sonic energy is transmitted through said chemical solvent to each group of junctions and into and laterally of each group of crevices whereby cavitation induced at each group of junctions and each group of crevices cooperates with said chemical solvent so as to enhance and accelerate the removal of the magnetite from all of the junctions and crevices;  h. continuing the cooperative action of said hot chemical solvent and said transducers upon each group of junctions and crevices until the magnetite is removed from all of the junctions and all of the crevices.  a. selecting a chemical solvent which when heated to a temperature between 120 degrees Fahrenheit and 220 degrees Fahrenheit dislodges the sludge from the base plate within 24 hours;  b. at least partially filling the tank with said chemical solvent, so as to establish an initial level which is only a few inches above the level of said base plate;  c. adding a metal corrosion inhibitor to said chemical solvent;  d. selecting a plurality of sonic transducers wherein each sonic transducer has a power output greater than about 0.2 watts per square centimenter at room temperature;  e. placing said plurality of sonic transducers at a level which is below the surface of said chemical solvent, substantially in the plane of said base plate, and in spaced locations around the circumference of the tank;  f. heating said chemical solvent to a temperature between 120 degrees Fahrenheit and 220 degrees Fahrenheit adjacent said base plate;  g. activating said sonic transducers to a frequency in the range of about 2 KHZ to 200 KHZ so that sonic energy is transmitted through said chemical solvent and into said sludge pile whereby cavitation induced at said base plate by said sonic energy cooperates with said chemical solvent so as to enchance and accelerate the removal of said sludge pile from said base plate;  h. continuing the cooperative actions of said hot chemical solvent and said transducers upon said base plate for several hours until the sludge pile is removed from said base plate; and  i. flushing said steam generator with a liquid to remove said sludge pile from said steam generator.  a. selecting a chemical solvent which when heated to a temperature between 120 degrees Fahrenheit and 220 degrees Fahrenheit dislodges the sludge from the base plate within 24 hours;  b. adding a metal corrosion inhibitor to said chemical solvent;  c. selecting a plurality of sonic transducers wherein each sonic transducer has a power output greater than about 0.2 watts per square centimenter at room temperature;  d. placing said plurality of sonic transducers at a level which is substantially in the plane of said base plate, and in spaced locations around the circumference of the tank;  e. heating said chemical solvent to a temperature between 120 degrees Fahrenheit and 220 degrees Fahrenheit at a location outside of said steam generator;  f. at least partially filling the tank with said chemical solvent, so as to establish an initial level which is only a few inches above the level of said base plate;  g. activating said sonic transducers to frequencies in the range of about 2 KHZ to 200 KHZ so that sonic energy is transmitted through said chemical solvent and into said sludge pile whereby cavitation induced at said base plate by said sonic energy cooperates with said chemical solvent so as to enhance and accelerate the removal of said sludge pile from said base plate;  h. continuing the cooperative actions of said hot chemical solvent and said transducers upon said base plate for several hours until the sludge pile is removed from said base plate; and  i. flushing said steam generator with a liquid to remove said sludge pile from said steam generator.  a. selecting a chemical solvent which when heated to a temperature between 120 degrees Fahrenheit and 220 degrees Fahrenheit dissolves magnetite exposed to fresh chemicals at a rate equal to or greater than about 1.0 inch per 24 hours;  b. at least partially filling the tank with said chemical solvent, so as to establish an initial level which is only a few inches above the level of the uppermost group of junctions and their uppermost group of crevices;  c. adding a metal corrosion inhibitor to said chemical solvent;  d. selecting a high boiling point fluid and placing the fluid in a plurality of thin flexible containers, wherein the combination of fluid and the thin flexible container has the same acoustic impedance as said metal wrapper;  e. placing said plurality of high boiling point fluid filled containers at a level which is below the surface of said chemical solvent, substantially in the plane of said uppermost group of junctions and uppermost group of crevices and in spaced locations around the circumference of and in contact with said metal wrapper;  f. selecting a plurality of sonic transducers wherein each sonic transducer has a power output greater than about 0.2 watts per square centimeter at room temperature;  g. placing said plurality of sonic transducers in alignment with and in contact with corresponding ones of said plurality of high boiling point fluid filled containers and also in contact with said metal wrapper;  h. running a hot fluid through said heat exchanger tubes so that the chemical solvent in the region adjacent said junctions and crevices reaches a temperature between 120 degrees Fahrenheit and 220 degrees Fahrenheit;  i. activating said sonic transducers to a frequency in the range of about 2 KHZ to 200 KHZ so that sonic energy is transmitted through said fluid filled containers, through said metal wrapper and through said chemical solvent, and to said junctions and into and laterally of said crevices whereby cavitation induced at said junctions and at said crevices by said sonic energy cooperates with said chemical solvent so as to enhance and accelerate the removal of the magnetite from said junctions and crevices;  j. continuing the cooperative action of said hot chemical solvent and said transducers upon said uppermost group of junctions and crevices until the magnetite is removed from the junctions and crevices;  k. then lowering the level of said chemical solvent to a height which is only a few inches above the next group of junctions and crevices from which magnetite is to be removed, lowering said plurality of high boiling point fluid filled containers and said plurality of transducers to a corresponding lower location on said metal wrapper in a plane substantially in alignment with said next group of junctions and crevices, and again applying said cooperative effort between said hot chemical solvent and said transducers until the magnetite is removed from said next group of junctions and next group of crevices; and  l. continuing in this fashion at the level of each successive group of junctions and crevices until all of said junctions and crevices have been cleaned.  a. cutting a plurality of windows in said metal wrapper such that a number of the windows are substantially in the plane of each group of junctions and in spaced locations around the circumference of and in contact with said metal wrapper;  b. selecting a plurality of sonic transducers wherein each sonic transducer has a power output greater than about 0.2 watts per square centimeter at room temperature;  c. placing said plurality of sonic transducers at a level which is substantially in the plane of each group of junctions, in spaced locations around and in contact with the circumference of said metal wrapper, and substantially in alignment with corresponding ones of said plurality of windows;  d. at least partially filling the tank with said chemical solvent so as to establish a level which is only a few inches above the level of the uppermost group of junctions;  e. adding a metal corrosion inhibitor to said chemical solvent;  f. running a hot fluid through said heat exchanger tubes so that the chemical solvent in the region adjacent said junctions reaches a temperature between 120 degrees Fahrenheit and 220 degrees Fahrenheit;  g. activating all the transducers simultaneously at each level substantially in the plane of each group of junctions and each group of crevices to a frequency in the range of about 2 KHZ to 200 KHZ so that sonic energy is transmitted through said chemical solvent to each group of junctions and into and laterally of each group of crevices whereby cavitation induced at each group of junctions and each group of crevices cooperates with said chemical solvent so as to enhance and accelerate the removal of the magnetite from all of the junctions and crevices;  h. continuing the cooperative action of said hot chemical solvent and said transducers upon each group of junctions and crevices until the magnetite is removed from all of the junctions and all of the crevices. 2. In the art of maintaining a steam generator for a nuclear power plane in which the steam generator is characterized by an enclosed tank containing a plurality of heat exchanger tubes and a plurality of support plates arranged transverse to and sequentially spaced along the longitudinal axes of the tubes and forming junctions therewith, where crevices exist between the heat exchanger tubes and the support plates at the site of the junctions, the junctions being thereby arranged in a series of groups, and also containing an outer shell and a metal wrapper inside the tank which envelops the plurality of tubes and support plates, and wherein magnetite tends to build up within the crevices at the junctions over a period of time, the process of removing the magnetite from the crevices and the junctions while the heat exchanger tubes and support plates remain in their operative positions inside the steam generator, comprising the steps of: 3. In the art of maintaining a steam generator for a nuclear power plant in which the steam generator is characterized by an enclosed tank containing a plurality of heat exchanger tubes and a plurality of support plates arranged transverse to and sequentially spaced along the longitudinal axes of the tubes and forming junctions therewith, where crevices exist between the heat exchanger tubes and the support plates at the site of the junctions, the junctions being thereby arranged in a series of groups, and also containing an outer shell and a metal wrapper inside the tank which envelops the plurality of tubes and support plates, and wherein magnetite tends to build up within the crevices at the junctions over a period of time, the process of removing the magnetite from the crevices and the junctions while the heat exchanger tubes and support plates remain in their operative positions inside the steam generator, comprising the steps of: 4. In the art of maintaining a steam generator for a nuclear power plant in which the steam generator is characterized by an enclosed tank containing a plurality of heat exchanger tubes and a plurality of support plates arranged transverse to and sequentially spaced along the longitudinal axes of the tubes and forming junctions therewith, where crevices exist between the heat exchanger tubes and the support plates at the site of the junctions, the junctions being thereby arranged in a series of groups, and also containing an outer shell and a metal wrapper inside the tank which envelops the plurality of tubes and support plates, and wherein magnetite tends to build up within the crevices at the junctions over a period of time, the process of removing the magnetite from the crevices and the junctions while the heat exchanger tubes and support plates remain in their operative positions inside the steam generator, comprising the steps of: 5. In the art of maintaining a steam generator for a nuclear power plant in which the steam generator is characterized by an enclosed tank containing a plurality of heat exchanger tubes and a plurality of support plates arranged transverse to and sequentially spaced along the longitudinal axes of the tubes and forming junctions therewith, where crevices exist between the heat exchanger tubes and the support plates at the site of the junctions, the junctions being thereby arranged in a series of groups, and also containing an outer shell and a metal wrapper inside the tank which envelops the plurality of tubes and support plates, and wherein magnetite tends to build up within the crevices at the junctions over a period of time, the process of removing the magnetite from the crevices and the junctions while the heat exchanger tubes and support plates remain in their operative positions inside the steam generator, comprising the steps of: 6. In the art of maintaining a steam generator for a nuclear power plant in which the steam generator is characterized by an enclosed tank containing a plurality of heat exchanger tubes and a plurality of support plates arranged transverse to and sequentially spaced along the longitudinal axes of the tubes and forming junctions therewith, where crevices exist between the heat exchanger tubes and the support plates at the site of the junctions, the junctions being thereby arranged in a series of groups, and also containing an outer shell and a metal wrapper inside the tank which envelops the plurality of tubes and support plates, and wherein magnetite tends to build up within the crevices at the junctions over a period of time, the process of removing the magnetite from the crevices and the junctions while the heat exchanger tubes and support plates remain in their operative positions inside the steam generator, comprising the steps of: 7. In the art of maintaining a steam generator for a nuclear power plant in which the steam generator is characterized by an enclosed tank containing a base plate on the lower portion of its interior surface, and wherein the products of corrosion, oxidation, sedimentation and comparable chemical reactions form a sludge pile over a period of time on the base plate, the process of removing the sludge pile while the base plate remains in its operative position inside the steam generator, comprising the steps of: 8. In the art of maintaining a steam generator for a nuclear power plant in which the steam generator is characterized by an enclosed tank containing a base plate on the lower portion of its interior surface, and wherein the products of corrosion, oxidation, sedimentation and comparable chemical reactions form a sludge pile over a period of time on the base plate, the process of removing the sludge pile while the base plate remains in its operative position inside the steam generator, comprising the steps of: 9. In the art of maintaining a steam generator for a nuclear power plant in which the steam generator is characterized by an enclosed tank containing a plurality of heat exchanger tubes and a plurality of support plates arranged transverse to and sequentially spaced along the longitudinal axes of the tubes and forming junctions therewith, where crevices exist between the heat exchanger tubes and the support plates at the site of the junctions, the junctions being thereby arranged in a series of groups, and also containing an outer shell and a metal wrapper inside the tank which envelopes the plurality of tubes and support plates, and wherein magnetite tends to build up within the crevices at the junctions over a period of time, the process of removing the magnetite from the crevices and the junctions while the heat exchanger tubes and support plates remain in their operative positions inside the steam generator, comprising the steps of: 10. The process as defined in claim 9 wherein said high boiling point fluid is oil and said container is a thin plastic bag. 11. The process as defined in claim 9 wherein said chemical solvent is heated to a temperature between 120 degrees Fahrenheit and 220 degrees Fahrenheit at a location outside said steam generator before it is placed into said steam generator as described. 12. In the art of maintaining a steam generator for a nuclear power plant in which the steam generator is characterized by an enclosed tank containing a plurality of heat exchanger tubes and a plurality of support plates arranged transverse to and sequentially spaced along the longitudinal axes of the tubes and forming junctions therewith, where crevices exist between the heat exchanger tubes and the support plates at the site of the junctions, the junctions being thereby arranged in a series of groups, and also containing an outer shell and a metal wrapper inside the tank which envelops the plurality of tubes and support plates, and wherein magnetite tends to build up within the crevices at the junctions over a period of time, the process of removing the magnetite from the crevices and the junctions while the heat exchanger tubes and support plates remain in their operative positions inside the steam generator, comprising the steps of: 13. The process as defined in claim 12 wherein said plurality of windows are each slightly smaller than the face of said transducers. 14. The process as defined in claim 12 wherein said plurality of windows are each slightly larger than the face of said transducer so that a portion of each transducer may protrude through said wrapper. 15. The process as defined in claim 12 wherein said chemical solvent is heated to a temperature between 120 degrees Fahrenheit and 220 degrees Fahrenheit before it is placed into the steam generator as described.