Heat Exchangers
1
Standards
of
Conduct
in Training
2
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?
3
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.
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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 SELECTION
Based 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 Sheet
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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
EO01
EO02
EO03
EO04
EO05
EO06
EO07
EO08
EO09
State the reasons for cleaning and inspecting heat
exchangers.
Describe the processes used to mechanically clean heat
exchanger tubes.
Describe the basic process used to chemically clean heat
exchanger tubes.
Describe the processes used to perform on-line cleaning of
heat exchanger tubes.
Describe the processes used to clean heat exchanger shells.
Identify the cleaning methods used on the Main Condensers,
MSR's and Feedwater Heaters at PVNGS.
Describe the general inspection procedures for the Moisture
Separator/Reheaters.
Describe the general inspection procedures for the Main
Condensers.
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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Air Requirements
- Minimum 70 PSI - Maximum 150 PSI
Water Requirements - Maximum 150 PSI
Water
Air
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)
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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 CONDENSER
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MSR
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MSR
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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
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MSR
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MSR Inspection through rear lower Man way
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MSR
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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
Manway
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LOW PRESSURE FEEDWATER HEATER
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Low Pressure
Feedwater
Heater
MAIN CONDENSER
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3 Parallel trains each consisting of 4 heat exchangers
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Bulging 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.
89
LESSON 3 ENABLING OBJECTIVES
EO01
EO02
EO03
EO04
EO05
EO06
EO07
EO08
EO09
EO10
Identify the common causes of heat exchanger tube leakage.
Describe the methods used to locate leaking heat exchanger
tubes.
Describe the general method used to plug leaking heat exchanger
tubes.
Describe the method used to plug leaking Feedwater Heater
tubes.
Describe the method used to plug leaking Main Condenser tubes.
Describe the method used to plug leaking Moisture
Separator/Reheater tubes.
Describe the methods of removing tubes from heat exchangers.
Describe the process used to replace tubes in heat exchangers
Describe the process of rolling tubes in tube sheets.
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 LOCATIONS
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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
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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 SEVERING
AND PLUGGING
TOOLS
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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 REMOVAL
TOOLING
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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
134
EO10 Describe the general procedure to
replace a heat exchanger tube
bundle.
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Replaceable tube bundle Example
Tube Bundle
O-Ring Seal
Channel cover
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The End
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