1 Heat Exchangers. Standards of Conduct in Training 2

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

13

14

15

16

17

HEAT EXCHANGER FUNCTIONS

•Raise system temperature

•Lower system temperature

•Remove latent heat

•Add latent heat

18

19

20

21

23

24

25

TUBE/SHELL SIDE FLUID SELECTIONBased on the following parameters

Cleanability

Corrosive fluid

Pressure

Temperature

Hazardous or Expensive Fluids

Consistency of Flow Characteristics

26

FIXED TUBE HX

27

Double Tube SheetDouble Tube Sheet

29

33

34

35

36

37

39

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 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.

42

EO01 State the reasons for cleaning and inspecting heat exchangers.

43

REASONS FOR CLEANING/INSPECTING

EFFICIENCY

MINIMIZE CORROSION/TUBING FAILURES

IDENTIFY PROBLEMS

Damage

Leaks

Fouling

44

45

46

47

48

49

50

51

52

PRECAUTIONS

TAGGING

CONFINED SPACE

CORRECT SIDE – TUBE/SHELL

INTERNAL HAZARDS

POTENTIAL TO DAMAGE TUBING [Shell Side]

53

54

EO02 Describe the processes used to mechanically clean heat exchanger tubes.

55

56

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

59

POWER TUBE CLEANING TOOLS (cont.)

60

EO03 Describe the basic process used to chemically clean heat exchanger tubes.

61

EO04 Describe the processes used to perform on-line cleaning of heat exchanger tubes.

62

63

64

EO05 Describe the processes used to clean heat exchanger shells.

65

EO06 Identify the cleaning methods used on the Main Condensers, MSR's and Feedwater Heaters at PVNGS.

66

67

MAIN CONDENSER68

MSR

69

MSR70

71

EO07 Describe the general inspection procedures for the Moisture Separator/Reheaters.

72

73

Valve Location

74

System Tie-In

MSR

75

76

MSR Inspection through rear lower Man way

77

78

MSR79

EO08 Describe the general inspection procedures for the Main Condensers.

80

MAIN CONDENSER INTERNALS LAYOUT

81

EXAMPLE MAIN CONDENSER

82

EO09 Describe the general inspection procedures for the Feedwater Heaters.

83

High Pressure Feedwater Heater

ManwayManway

84

LOW PRESSURE FEEDWATER HEATER

85

MAIN CONDENSER

Low Pressure Low Pressure Feedwater Feedwater

HeaterHeater

86

3 Parallel trains each consisting of 4 heat exchangers

87

Bulging diaphragm from event at SeabrookBulging 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 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.

90

EO01 Identify the common causes of heat exchanger tube leakage.

91

LEAK LOCATIONS92

93

94

95

96

97

98

99

100

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

EO02 Describe the methods used to locate leaking heat exchanger tubes.

103

104

105

106

107

108

TUBESHEET LAYOUT MAP 109

EO03 Describe the general method used to plug leaking heat exchanger tubes.

110

111

112

113

114

EO04 Describe the method used to plug leaking Feedwater Heater tubes.

115

116

FEEDWATER HEATER TUBE PLUG

117

118

EO05 Describe the method used to plug leaking Main Condenser tubes.

120

EO06 Describe the method used to plug leaking Moisture Separator/Reheater tubes.

121

MSR SEVERINGAND PLUGGINGTOOLS

122

MSR TUBE PLUGGED

123

EO07 Describe the methods of removing tubes from heat exchangers.

124

TUBING REMOVALTOOLING

125

126

127

EO08 Describe the process used to replace tubes in heat exchangers

128

129

EO09 Describe the process of rolling tubes in tube sheets.

130

131

TUBING EXPANDER TOOLING

132

TUBING EXPANDER TOOLING

133

TUBING ROLLER EXAMPLES

134

EO10 Describe the general procedure to replace a heat exchanger tube bundle.

135

Channel Channel covercover

Tube Tube BundleBundle

O-Ring SealO-Ring Seal

Replaceable tube bundle Replaceable tube bundle ExampleExample

136

The End

137

138

139

140