1 Heat Exchangers

Standards of Conduct in Training 2

3 What are the critical steps of the task? What are the error likely situations? What is the worst thing that could happen? What are the specific error prevention defenses that can be used? What actions can be taken to assure proper configuration control?

COURSE TERMINAL OBJECTIVE Given a maintenance activity involving Heat Exchangers (condensers, re-heaters, heaters, etc.), describe the inspection, cleaning, repair and rework methods used at Palo Verde, in accordance with plant procedures, manufacturer’s technical manuals, and standard maintenance practices, as demonstrated by achieving a minimum score of 80% on a written exam. 4

LESSON TERMINAL OBJECTIVE Given a maintenance operation involving heat exchangers, the Plant Mechanic will describe the theory of operation and basic construction of heat exchangers, as demonstrated by achieving a minimum score of 80% on a written examination. 5

LESSON ENABLING OBJECTIVES EO01 State the basic theory of heat transfer. EO02 Define the three mechanisms of heat transfer. EO03 List the four (4) functions performed by heat exchangers EO04 Classify heat exchangers by their construction. EO05 Identify five (5) factors which affect heat exchanger operation. 6

HEAT Heat is energy in transit from one mass to another because of the temperature difference between the two. Heat: a form of energy associated with the motion of atoms or molecules and transferred from a body at a HIGHER Temperature to one at a LOWER Temperature. 7

Temperature A measure of the ability to transfer heat. Heat exchanger: Device to transfer heat from one fluid to another. 8

Principles of Heat Heat energy will move from a high energy state to that of a lower energy state. The process will continue until a state of Equilibrium is reached. Energy will flow from a “hot” material to a “cold” material. 9

Mechanisms for heat transfer Conduction Convection: Natural and Forced Radiation: The only method of heat transfer through a vacuum. 10

Heat Transfer Coefficient The Measure of the material’s ability to transfer heat. The higher the value, the more heat transfers through the material. 11

CONDUCTION The transfer of heat from one part of a body to another part or to another body by short range interactions of molecules and/or electrons. 12

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HEAT EXCHANGER FUNCTIONS Raise system temperature Lower system temperature Remove latent heat Add latent heat 18

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TUBE/SHELL SIDE FLUID SELECTION Based on the following parameters Cleanability Corrosive fluid Pressure Temperature Hazardous or Expensive Fluids Consistency of Flow Characteristics 26

FIXED TUBE HX 27

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Double Tube Sheet 29

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FIVE FACTORS THAT AFFECT HX OPERATION TEMPERATURE DIFFERENCE FLUID FILM RESISTANCE FILM COEFFICIENT SURFACE AREA FLUID VELOCITY 40

LESSON 2 TERMINAL OBJECTIVE Given a maintenance activity involving Heat Exchangers the Plant Mechanic will state the steps necessary to clean and inspect heat exchangers as demonstrated by achieving a minimum score of 80% on a written examination. 41

LESSON 2 ENABLING OBJECTIVES EO01State the reasons for cleaning and inspecting heat exchangers. EO02Describe the processes used to mechanically clean heat exchanger tubes. EO03Describe the basic process used to chemically clean heat exchanger tubes. EO04Describe the processes used to perform on-line cleaning of heat exchanger tubes. EO05Describe the processes used to clean heat exchanger shells. EO06Identify the cleaning methods used on the Main Condensers, MSR's and Feedwater Heaters at PVNGS. EO07Describe the general inspection procedures for the Moisture Separator/Reheaters. EO08Describe the general inspection procedures for the Main Condensers. EO09Describe the general inspection procedures for the Feedwater Heaters. 42

EO01State the reasons for cleaning and inspecting heat exchangers. 43

REASONS FOR CLEANING/INSPECTING EFFICIENCY MINIMIZE CORROSION/TUBING FAILURES IDENTIFY PROBLEMS Damage Leaks Fouling 44

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PRECAUTIONS TAGGING CONFINED SPACE CORRECT SIDE – TUBE/SHELL INTERNAL HAZARDS POTENTIAL TO DAMAGE TUBING [Shell Side] 53

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EO02Describe the processes used to mechanically clean heat exchanger tubes. 55

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TUBE CLEANING TOOLS 57

LP FW Heater # 1 (#2 Rubber Plugs For Rubber Ducky Test) 0.750” OD, 22BWG, 1690 Tubes (3380 Upper and Lower) LP FW Heater # 2 (#3 Rubber Plugs For Rubber Ducky Test) 0.875” OD, 22BWG, 857 Tubes (1714 Upper and Lower) LP FW Heater # 3 (#3 Rubber Plugs For Rubber Ducky Test) 0.875” OD, 22BWG, 857 Tubes (1714 Upper and Lower) LP FW Heater # 4 (#3 Rubber Plugs For Rubber Ducky Test) 0.875” OD, 22BWG, 857 Tubes (1714 Upper and Lower) Air Requirements - Minimum 70 PSI - Maximum 150 PSI Water Requirements - Maximum 150 PSI AirWater 58

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POWER TUBE CLEANING TOOLS (cont.) 60

EO03Describe the basic process used to chemically clean heat exchanger tubes. 61

EO04Describe the processes used to perform on-line cleaning of heat exchanger tubes. 62

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EO05Describe the processes used to clean heat exchanger shells. 65

EO06Identify the cleaning methods used on the Main Condensers, MSR's and Feedwater Heaters at PVNGS. 66

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MAIN CONDENSER 68

MSR 69

MSR 70

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EO07Describe the general inspection procedures for the Moisture Separator/Reheaters. 72

73 Valve Location

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MSR 75

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MSR Inspection through rear lower Man way 77

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MSR 79

EO08Describe the general inspection procedures for the Main Condensers. 80

MAIN CONDENSER INTERNALS LAYOUT 81

EXAMPLE MAIN CONDENSER 82

EO09Describe the general inspection procedures for the Feedwater Heaters. 83

High Pressure Feedwater Heater Manway 84

LOW PRESSURE FEEDWATER HEATER 85

MAIN CONDENSER Low Pressure Feedwater Heater 86

3 Parallel trains each consisting of 4 heat exchangers 87

Bulging diaphragm from event at Seabrook 88

LESSON 3 TERMINAL OBJECTIVE Given a heat exchanger maintenance activity the maintenance mechanic will describe the methods used to locate leaking tubes, and to plug, rework, or replace the heat exchanger tubes, as demonstrated by achieving a minimum score of 80% on a written examination. 89

LESSON 3 ENABLING OBJECTIVES EO01Identify the common causes of heat exchanger tube leakage. EO02Describe the methods used to locate leaking heat exchanger tubes. EO03Describe the general method used to plug leaking heat exchanger tubes. EO04Describe the method used to plug leaking Feedwater Heater tubes. EO05Describe the method used to plug leaking Main Condenser tubes. EO06Describe the method used to plug leaking Moisture Separator/Reheater tubes. EO07Describe the methods of removing tubes from heat exchangers. EO08Describe the process used to replace tubes in heat exchangers EO09Describe the process of rolling tubes in tube sheets. EO10Describe the general procedure to replace a heat exchanger tube bundle. 90

EO01Identify the common causes of heat exchanger tube leakage. 91

LEAK LOCATIONS 92

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INDICATIONS OF MINOR TUBE LEAKAGE IN STEAM GENERATORS 1. MAIN STEAM LINE RADIATION HIGH 2. CONDENSER OFF GAS RADIATION HIGH 3. STEAM GENERATOR BLOWDOWN RADIATION HIGH 4. CHARGING/ LETDOWN FLOW MISMATCH 5. DECREASING LEVEL IN VCT 6. SECONDARY SIDE SAMPLE ACTIVITY HIGH 101

INDICATIONS OF LEAK IN MAIN CONDENSER 1. AN INCREASE ON ANY HOTWELL SODIUM INDICATION 2. A CORRESPONDING INCREASE IN HOTWELL CATION CONDUCTIVITY 3. AN AUTO ISOLATION OF THE CONDENSATE REJECT VALVE DUE TO CONDUCTIVITY 4. THERE MAY BE AN INCREASE IN HOTWELL LEVEL DEPENDING ON THE SIZE OF THE LEAK 102

EO02Describe the methods used to locate leaking heat exchanger tubes. 103

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TUBESHEET LAYOUT MAP 109

EO03Describe the general method used to plug leaking heat exchanger tubes. 110

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EO04Describe the method used to plug leaking Feedwater Heater tubes. 115

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FEEDWATER HEATER TUBE PLUG 117

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EO05Describe the method used to plug leaking Main Condenser tubes. 120

EO06Describe the method used to plug leaking Moisture Separator/Reheater tubes. 121

MSR SEVERING AND PLUGGING TOOLS 122

MSR TUBE PLUGGED 123

EO07Describe the methods of removing tubes from heat exchangers. 124

TUBING REMOVAL TOOLING 125

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EO08Describe the process used to replace tubes in heat exchangers 128

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EO09Describe the process of rolling tubes in tube sheets. 130

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TUBING EXPANDER TOOLING 132

TUBING EXPANDER TOOLING 133

TUBING ROLLER EXAMPLES 134

EO10Describe the general procedure to replace a heat exchanger tube bundle. 135

Channel cover Tube Bundle O-Ring Seal Replaceable tube bundle Example 136

The End 137

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