1 Heat Exchangers. Standards of Conduct in Training 2.
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Heat Exchangers
Standards of
Conduct in Training
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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.
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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.
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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.
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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.
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Temperature
• A measure of the ability to transfer heat.
• Heat exchanger: Device to transfer heat from one fluid to another.
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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.
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Mechanisms for heat transfer
• Conduction
• Convection: Natural and Forced
• Radiation: The only method of heat transfer through a vacuum.
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Heat Transfer Coefficient
The Measure of the material’s ability to transfer heat.
The higher the value, the more heat transfers through the material.
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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.
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HEAT EXCHANGER FUNCTIONS
•Raise system temperature
•Lower system temperature
•Remove latent heat
•Add latent heat
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TUBE/SHELL SIDE FLUID SELECTIONBased on the following parameters
Cleanability
Corrosive fluid
Pressure
Temperature
Hazardous or Expensive Fluids
Consistency of Flow Characteristics
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FIXED TUBE HX
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Double Tube SheetDouble Tube Sheet
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FIVE FACTORS THAT AFFECT HX OPERATION
TEMPERATURE DIFFERENCE
FLUID FILM RESISTANCE
FILM COEFFICIENT
SURFACE AREA
FLUID VELOCITY
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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.
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LESSON 2 ENABLING OBJECTIVESEO01 State the reasons for cleaning and inspecting heat
exchangers.EO02 Describe the processes used to mechanically clean heat
exchanger tubes.EO03 Describe the basic process used to chemically clean heat
exchanger tubes.EO04 Describe the processes used to perform on-line cleaning of
heat exchanger tubes.EO05 Describe the processes used to clean heat exchanger shells.EO06 Identify the cleaning methods used on the Main Condensers,
MSR's and Feedwater Heaters at PVNGS.EO07 Describe the general inspection procedures for the Moisture
Separator/Reheaters.EO08 Describe the general inspection procedures for the Main
Condensers.EO09 Describe the general inspection procedures for the Feedwater
Heaters.
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EO01 State the reasons for cleaning and inspecting heat exchangers.
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REASONS FOR CLEANING/INSPECTING
EFFICIENCY
MINIMIZE CORROSION/TUBING FAILURES
IDENTIFY PROBLEMS
Damage
Leaks
Fouling
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PRECAUTIONS
TAGGING
CONFINED SPACE
CORRECT SIDE – TUBE/SHELL
INTERNAL HAZARDS
POTENTIAL TO DAMAGE TUBING [Shell Side]
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EO02 Describe the processes used to mechanically clean heat exchanger tubes.
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TUBE CLEANING TOOLS
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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
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POWER TUBE CLEANING TOOLS (cont.)
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EO03 Describe the basic process used to chemically clean heat exchanger tubes.
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EO04 Describe the processes used to perform on-line cleaning of heat exchanger tubes.
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EO05 Describe the processes used to clean heat exchanger shells.
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EO06 Identify the cleaning methods used on the Main Condensers, MSR's and Feedwater Heaters at PVNGS.
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MAIN CONDENSER68
MSR
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MSR70
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EO07 Describe the general inspection procedures for the Moisture Separator/Reheaters.
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Valve Location
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System Tie-In
MSR
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MSR Inspection through rear lower Man way
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MSR79
EO08 Describe the general inspection procedures for the Main Condensers.
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MAIN CONDENSER INTERNALS LAYOUT
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EXAMPLE MAIN CONDENSER
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EO09 Describe the general inspection procedures for the Feedwater Heaters.
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High Pressure Feedwater Heater
ManwayManway
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LOW PRESSURE FEEDWATER HEATER
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MAIN CONDENSER
Low Pressure Low Pressure Feedwater Feedwater
HeaterHeater
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3 Parallel trains each consisting of 4 heat exchangers
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Bulging diaphragm from event at SeabrookBulging diaphragm from event at Seabrook
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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.
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LESSON 3 ENABLING OBJECTIVESEO01 Identify the common causes of heat exchanger tube leakage.EO02 Describe the methods used to locate leaking heat exchanger
tubes.EO03 Describe the general method used to plug leaking heat exchanger
tubes.EO04 Describe the method used to plug leaking Feedwater Heater
tubes.EO05 Describe the method used to plug leaking Main Condenser tubes.EO06 Describe the method used to plug leaking Moisture
Separator/Reheater tubes.EO07 Describe the methods of removing tubes from heat exchangers.EO08 Describe the process used to replace tubes in heat exchangersEO09 Describe the process of rolling tubes in tube sheets.EO10 Describe the general procedure to replace a heat exchanger tube
bundle.
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EO01 Identify the common causes of heat exchanger tube leakage.
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LEAK LOCATIONS92
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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
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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
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EO02 Describe the methods used to locate leaking heat exchanger tubes.
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TUBESHEET LAYOUT MAP 109
EO03 Describe the general method used to plug leaking heat exchanger tubes.
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EO04 Describe the method used to plug leaking Feedwater Heater tubes.
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FEEDWATER HEATER TUBE PLUG
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EO05 Describe the method used to plug leaking Main Condenser tubes.
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EO06 Describe the method used to plug leaking Moisture Separator/Reheater tubes.
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MSR SEVERINGAND PLUGGINGTOOLS
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MSR TUBE PLUGGED
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EO07 Describe the methods of removing tubes from heat exchangers.
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TUBING REMOVALTOOLING
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EO08 Describe the process used to replace tubes in heat exchangers
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EO09 Describe the process of rolling tubes in tube sheets.
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TUBING EXPANDER TOOLING
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TUBING EXPANDER TOOLING
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TUBING ROLLER EXAMPLES
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EO10 Describe the general procedure to replace a heat exchanger tube bundle.
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Channel Channel covercover
Tube Tube BundleBundle
O-Ring SealO-Ring Seal
Replaceable tube bundle Replaceable tube bundle ExampleExample
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The End
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