NUREG/CR-55 19

ORNL-6607/V1

Vol. 1

Aging of Control and Service

Air Compressors and Dryers

Used in Nuclear Power Plants

Prepared by J. C. Moyers

Oak Ridge National Laboratory

Prepared for

U.S. Nuclear Regulatory Commission

I - ________
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NUREG/CR-55 19

ORNL-6607/V1

Vol. 1

RV

Aging of Control and Service

Air Compressors and Dryers

Used in Nuclear Power Plants

Manuscript Completed: May 1990

Date Published: July 1990

Prepared by

J. C. Moyers

Oak Ridge National Laboratory

Operated by Martin Marieta Energy Systems, Inc.

Oak Ridge National Laboratory

Oak Ridge, TN 37831

Prepared for

Division of Engineering

Office of Nuclear Regulatory Research

U.S. Nuclear Regulatory Commission

Washington, DC 20555

NRC FIN B0828

Under Contract No. DE-ACO5-840R21400
iii

CONTENTS

Page

LIST OF FIGURES * ............................................... v

LIST OF TABLES ................ v.i................ii

SUMMARY ........ ........ *.....i

ABSTRACT * ... OO@606604eO*@ 646 6@**..* 1

161 Background ................ . ............................ 1

1.2 Objective .............................................. 2

1.3 Project Scope .......................................... 2

1.4 Definitions ............................................ 3

2. BASIC INFORMATION ......... ... ................................ 4

2.1 Principal Types and Uses of Air Compressors and

Dryers in BWRs and PWRs ................................ 4

2.2 Compressors .............. , 6

2.2.1 Compressor types ....... ......................... 6

2.2.2 Compressor equipment boundaries ................. 12

2.2.3 Compressor functional requirements .............. 12

2.2.4 Compressor materials of construction ............ 12

2.3 Dryers .. ...... , 12

2.3.1 Dryer types ..................................... 12

2.3.2 Dryer equipment boundaries ...................... 17

2.3.3 Dryer functional requirements ................... 17

2.3.4 Dryer materials of construction ................. 17

3. TECHNICAL SPECIFICATION REQUIREMENTS ....................... 18

4. SUMMARY OF OPERATIONAL-STRESSORS ............................ 19

4.1 Compressors ......................................... ... 19

4.1.1 Electrical stressors ..... ....................... 19

4.1.1.1 Drive motor ........................... 19

4.1.1.2 Protective switches .................... 19

4.1.1.3 Solenoid valves 19........................ 

4.1.2 Mechanical stressors ..... ....................... 20

4.1.2.1 Running gear ..... ...................... 20

4.1.2.2 Cylinder/piston assembly ............... 21

4.1.3 Thermal stressors .. 6.6.6 ...................... 22

4.1.4 Chemical stressors ............................. 23

4.1.5 Radiation stressors ............................ 23

4.1.6 Environmental stressors ......................... 23
iv

CONTENTS (continued)

Page

4.2 Dryers ................................................. 23

4.2.1 Electrical stressors ..... ....................... 23

4.2.2 Mechanical stressors ........................... , 24

4.2.3 Thermal stressors Ce........ *. 24

4.2.4 Chemical, radiation and environmental

stressors ................................... 24

5. OPERATING EXPERIENCE ......... .... ... ...... .. .. .. 25

5.1 Information Sources .................. CC...........C.CC.C.CCCC. 25

5.2 Summary of Failure Modes and Causes .................... 26

5.2.1 Compressors ........ ................ ........ 26

5.2.2 Dryers ......... ** ........... ..... 30

5.3 Frequency of Failures .... C C31

5.3.1 Compressors .. CC.C...CCC.CCCCCCC 31

5.3.2 Dryers CCCCCCCC CCC*CCCCC CCCC*CCCCCCC C CCC CC...... 33

5.4 Methods of Detection CCCCCCCCC *C CCC...... ..... 35

6. MANUFACTURER-RECOMMENDED AND USER-APPLIED MAINTENANCE

AND SURVEILLANCE PRACTICES C CCC CCCC.............. C C C C C C CCC C C C C C 36

6.1 Manufacturer-Recommended Practices for Compressors ..... 36

6.2 User-Applied Practices for Compressors ................. 37

6.3 Manufacturer-Recommended Practices for Dryers .......... 39

6.4 User-Applied Practices for Dryers .... .................. 40

7. AGING MONITORING AND ASSESSMENT CCCCCCCC.................... 41

7.1 Failure Mode and Cause Determination CCCCCC.C....CCCC. 41

7.2 Measurable Parameters for Establishing Degradation

Trends CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC 44

7.2.1 Compressors . . . .......... .......... 44

7.2.2 Dryers CCCCCC* CCCCCC* CCCCCCC CCCCCC CCCCCCCC CCCCCCC 50

8. SUMMARY AND RECOMMENDATIONS CCCCC..............C.C.C.C.C.C.C.C.C.C.C.C.C.C.C.C.C.C.C.C 52

REFERENCES ......... CCC.CCCCCCCCC.CCCCC.CCC .CCC.CCCCCC.C..CC.CCCCCC.C 53

APPENDIX A. AIR COMPRESSORS AND DRYERS IN U.S. NUCLEAR

PLANTS AS DESCRIBED IN SAFETY ANALYSIS REPORTS ..... 55

APPENDIX B. COMPRESSOR AND DRYER PROBLEMS FROM LER AND NPE

SEARCHES CCCCCCCCC CCCCCCC CCCC CCCCCCCCC CCCCCCC ....... 65

APPENDIX C. IPRDS SERVICE COMPRESSOR AND DRYER MAINTENANCE

CALLS .................................... 75

APPENDIX D. UTILITY NUCLEAR PLANT AIR COMPRESSOR AND DRYER

MAINTENANCE CALLS ....CCC CCC.CCCCCCC...............CC C C 93
v

LIST OF FIGURES

Figure Page

2.1 Nonlubricated reciprocating compressor schematic ....... 7

2.2 Cross-sectional view of low-pressure cylinder .......... 9

2.3 Cross-sectional view of high-pressure cylinder ......... 9

2.4 Typical inlet and discharge channel valves ............. 10

2.6 Refrigerated air dryer schematic ....................... 13

2.7 Heat regenerated dryer schematic ....................... 15

2.8 Heatless dryer schematic ............................... 15

2.9 Units using various types of air dryers ................ 16
vii

LIST OF TABLES

Table Page

2.1 Incidence of use of various compressor types in U.S.

nuclear power units ....... ............ ........ 6

2.2 Compressor materials of construction .................... 13

5.1 Summary of Compressor Failures/Problems ................. 27

5.2 Summary of Dryer Failures/Problems ...................... 30

5.3 Chronology of Maintenance Calls for IPRDS Plant

Compresor o ... enanc CallsforUtily... ... 32

5.4 Chronology of Maintenance Calls for Utility Plant

Compressors ............................. 33

5.6 Chronology of Maintenance Calls for IPRDS Plant

Dryers ............................. 34

5.6 Chronology of Maintenance Calls for Utility Plant

Dryers ............................. 34

6.1 Preventative Maintenance Procedures for Control/

Service Compressors .......... ........... .. ............ 38

6.2 Preventative Maintenance Procedures for Auxiliary

Compressors ............................. 38

6.3 Preventative Maintenance Procedures for Dryers ........... 40

7.1 Methods for Differentiating Between Compressor

Failure Causes ........................................ 42

7.2 Methods for Differentiating Between Dryer Failure

Causes ............................. 45

7.3 Measurable Parameters for Compressors ................... 47

7.4 Effects of Faulty Components on Stage Temperatures

and Pressures for4Dryers9........................ 49

7.5 Measurable Parameters for Dryers ................ 0........................ 51
ix

ACKNOWLEDCGENTS

The author gratefully acknowledges the continuing support and counsel of the NRC Nuclear Plant Aging Research Program manager, J. P. Vora,

and project manager, W. S. Farmer, in the planning and implementing of

this study.

The assessment was carried out under the general guidance of D. M.

Eissenberg, ORNL PAR Program manager; the author appreciates his

encouragement and advice. D. A. Casada of ORNL's PAR staff was very

helpful in sharing his experience in the nuclear plant operating

environment.

The assistance provided by Sam Denton of Air Components and Systems, Knoxville, in providing equipment manuals and insights on the

operation and maintenance of the equipment and in obtaining permission

to include illustrations from the Ingersoll-Rand compressor manual, is

gratefully acknowledged.

The author also is grateful to personnel associated with the

Tennessee Valley Authority's Sequoyah Nuclear Plant, especially to Steve

Smith, former plant manager, Isadore Debiassi, preventative maintenance

manager, and Chuck Hood, engineer, for their cooperation in providing

detailed maintenance information for their plant.
xi

SUMMARY

This report presents the results of a Phase I assessment of the

time-related degradation (aging) of air compressors and dryers used to

provide control and service compressed air in nuclear power plants. The

assessment was sponsored by the Office of Nuclear Regulatory Research,

Nuclear Regulatory Commission, as an element of the ongoing Nuclear

Plant Aging Research (PAR) Program. The objective of an NPAR Phase I

assessment is to review operating experience and manufacturers' information, to identify failure modes and causes resulting from aging, and to

identify measurable parameters that might provide a better indication of

equipment condition.

The report briefly reviews typical compressors and dryers in

nuclear power plants and identifies the nonlubricated reciprocating compressor as the type used in more plants than any other, for both service

and control air; for this reason, the assessment focused on this type.

Similarly, regenerative desiccant dryers are most often used and

received primary emphasis in the assessment. A general description of

the equipment is provided and includes illustrations, defined equipment

boundaries, functional requirements, and materials of construction.

Operational stressors are categorized, and a detailed stressor list is

provided.

Operating experiences reported in data bases for nuclear power

plants and in nuclear industry reports were examined. These data bases

included the Licensee Event Report file as cataloged in the Sequence

Coding and Search System maintained by ORNL's Nuclear Operations Analysis Center, the Nuclear Power Experience compilation maintained and published by Stoller Power, Inc., the In-Plant Reliability Data System containing maintenance records for one utility plant, and maintenance

records obtained from a cooperating utility for a second plant. During

the 1978-1988 decade covered by the LER data, which represents -812

reactor unit-years, a total of 22 compressor-related and 16 dryerrelated events that resulted in loss of control air supply were

reported. Equipment failure causes were diverse, with no single type of

failure dominating. The records available for the two utility plants

indicate a significant preventative and corrective maintenance effort to

correct for service wear and provide reliable equipment operation.

Maintenance recommendations included in operating and maintenance

manuals provided by equipment manufacturers were reviewed and were compared to the preventative maintenance practices at one utility plant.

The user-applied practices generally were in conformance with or

exceeded the manufacturers' recommendations. One troublesome aspect is

that of assuring operational readiness of auxiliary compressors that

normally sit idle for long periods of time but that must provide backup

service for critical needs if the main control air supply deteriorates.

Manufacturer-recommended mothballing procedures do not appear practical

for this application; such failure causes as permanent set of drive

belts, corrosion of internal parts, and small internal water leaks may

present a problem when the compressor is needed.
xti

Measurable parameters were identified that have potential for

enhancing capabilities for incipient failure detection and examining

degradation trends in compressors and dryers. For compressors, these

include periodic delivery capacity tests, trending of stage temperatures

and pressures, and motor current signature analysis. For dryers,

identified measurable parameters include moisture sensing within but

near the exit of the desiccant column and periodic monitoring of the

axial temperature profile within the column. Use of these measurable

parameters in the surveillance and monitoring program might reduce the

level of time-directed, out-of-service, inspection and maintenance,

thereby increasing availability and improving overall system reliability.

Nuclear plant control and service air compressors and dryers are

not usually considered as safety-related, because the air systems are

not needed to bring the plant to a safe shutdown condition. An effective surveillance and monitoring program, with preventative and corrective maintenance, can provide reliable service from nuclear plant compressors and dryers. Instances where loss of air supply occurs due to

compressor or dryer failure are rare, due both to rare occurrences of

equipment failure to operate and to redundancy provided by most systems.

For these reasons, it is recommended that no further consideration of

aging of this equipment be included in the NPAR program.
AGING OF CONTROL AND SERVICE AIR COMPRESSORS

AND DRYERS USED IN NUCLEAR POWER PLANTS

Volume 1. Operating Experience and

Failure Identification

J. C. Moyers

ABSTRACT

This report was' produced under the Detection of Defects

and Degradation Monitoring of Nuclear Plant Safety Equipment

element of the Nuclear Plant Aging Research Program. This

element includes the identification of practical and costeffective methods for detecting, monitoring, and assessing

the severity of time-dependent degradation (aging) of control and service air compressors and dryers in nuclear power

'plants. These methods are to provide capabilities for establishing degradation trends prior to failure and developing

guidance for effective maintenance.

The topics of this Phase I assessment report are failuse modes and causes resulting from aging, manufacturerrecommended maintenance and surveillance practices, and

measurable parameters (including functional indicators) for

use in assessing operational readiness, establishing

degradation -trends, and detecting incipient failure. The

results presented are based on information derived from

operating experience records, manufacturer-supplied information, and input from plant operators.

For each failure mode, failure causes are listed by

subcomponent, and parameters potentially useful for detecting degradation that could lead to failure are identified.

1. INTRODUCTION

1.1 Background

The Office of Nuclear Regulatory Research of the Nuclear Regulatory

Commission (NRC) has an ongoing program, the Nuclear Plant Aging

Research (NPAR) Program,1 aimed at understanding the time-related

degradation (aging) of nuclear power plant systems and equipment. It

includes assessing the effectiveness of methods of inspection and surveillance that monitor such degradation and establishing guidelines for

maintenance. The program is intended to provide technical bases for

examining the ongoing operational safety of operating plants.
2

This report addresses the time-related degradation of air compressors and dryers. Other components being studied in the Nuclear Plant

Aging Research (NPAR) Program include motor-operated valves, check

valves, auxiliary feedwater pumps, diesel generators, snubbers, batteries, chargers, and inverters.

Compressors and dryers, which are vital components of the plant

service and control air systems, are not normally classified as safetyrelated components because their continued operation is not required to

bring the plant to a safe shutdown condition. However, a reliable

supply of clean, dry, control air is required to maintain stable plant

operation. Loss of that supply often results in a reactor trip and, on

occasion, actuation of the plant's Engineered Safety Feature systems,

thus presenting a challenge to the safety-related systems. Safet3

implications of outages of control air systems have been documented"

and concern for those implications resulted in the assignment of a high

priority to Generic Issue No. 43, "Air Systems Reliability".4 An aging

assessment of instrument air systems in nuclear power plants,5 covering

the total system but with less detail on compressors and dryers than

included in this assessment, recently has been completed by Brookhaven

National Laboratory.

1.2 Objective

The objective of this NPAR Program element is to review operating

experience and manufacturers' information, to identify failure modes and

causes resulting from aging of air compressors and dryers in nuclear

plant service, and to identify measurable parameters which, if tracked

in improved inspection, surveillance, and monitoring procedures, might

result in improved system reliability.

1.3 Project Scope

This assessment covers the following information for air compressors and dryers used in plant air and control air systems of nuclear

power plants.

1. Background information on compressors and dryers - boundary of

equipment to be studied, types, uses, requirements, and materials of

construction

2. Reviews of regulatory requirements, guides, and standards

3. Summary of operational and environmental stressors

4. Summary of operating experience

5. Manufacturers' input

6. State-of-the-art aging monitoring and assessment

Because the majority of the presently operating nuclear plants rely

on nonlubricated reciprocating compressors and regenerative desiccant

dryers, the assessment is focused primarily on these types of units.
3

1.4 Definitions

For the purpose of this report, the following definitions apply:

Failure mode - the way in which a component does not perform a

function for which it was designed.

Failure cause - degradation (the presence of a defect) in a component that is the proximate cause of its failure; for example, bent

shaft, loss of'lubricant or coolant, and loosening of a fastener.

Failure mechanisms - the phenomena that are responsible for the

degradation present in a given component at a given time. Frequently,

several failure mechanisms are collectively responsible for degradation

(synergistic influences). Where one major failure mechanism is identified, it has been called the "root cause." Ceneric examples of failure

mechanisms (and of root causes) include aging, human error, and seismic

events.

Aging - the combined cumulative effects over time of internal and

external stressors acting on a component, leading to degradation of the

component which increases with time. Aging degradation may involve

changes in chemical, physical, electrical, or metallurgical properties,

dimensions, and/or relative positions of individual parts.

Normal aging - aging of a component that has been designed, fabricated, installed, operated, and maintained'in accordance with. specifications, instructions, and good practice, and that results from exposure

to normal stressors for the specific application. Normal aging should

zbeitaken into account in component design and specifications.

Measurable parameters - physical or chemical characteristics of a

component that can be described or measured directly or indirectly and

that can be correlated with aging. Useful measurable parameters are

those that can be used to establish trends of the magnitude of aging

associated with each failure cause, that have well-defined criteria for

quantifying the approach to failure, and that are able to discriminate

between the degradation that leads to failure and other degradation.

Inspection, surveillance, and condition monitoring (ISCK) - the

spectrum of methods for obtaining qualitative or quantitative values of

a measurable parameter of a component. The methods may be periodic or

continuous, may be in-plant or may require removal and installation in a

test stand or disassembly, and may involve dynamic or static measurements.
4

2. BASIC INFORMATION

2.1 Principal Types and Uses of Air Compressors

and Dryers in BWRs and PWRs

The two principal applications of air compressors in pressurizedwater reactor (PWR) and boiling-water reactor (BWR) nuclear power plants

are to provide plant service air and control (or instrument) air. Plant

service air is used for general plant maintenance purposes, such as in

the operation of pneumatic tools, and the presence of small amounts of

moisture and oil is acceptable. Control air is used as the motive power

source for many pneumatically operated valves throughout the plants.

Gross accumulations of oil, water, or solid contaminants in air lines

and valve operators can result in valve operator malfunction. Even

minute amounts of these liquid or solid contaminants can cause malfunctions in the solenoid-operated valves, check valves, and electronic-topneumatic converters used to direct and control the air supply to the

pneumatically operated valves. Therefore, cleanliness and dryness are

prime requirements for the control air system.

Compressors used to provide control air are usually of the

nonlubricated, oil-free, type. The terms 'nonlubricated' and 'oil-free'

pertain to the region of the machine in contact with the air being compressed; the running gear of this type unit is oil-lubricated but the

design prevents migration of oil into the air-compression cylinder

region. Cylinder lubrication in oil-lubricated machines is not by

running gear oil but by controlled injection of cylinder oil.

Because the plant service air system is often considered as backup

in the event of loss of the control air compressors, the service air

compressors are often of the nonlubricated type also. In many plants,

both service air and control air are provided by the same non-lubricated

compressors, with control air taken from common headers passing through

filter-dryers before being distributed to the using areas. When oillubricated compressors are used to provide service air, oil separators

are installed to reduce oil carryover into the control air system during

cross-connected operation. System pressure for both service and control

air systems is nominally 100 psig. Capacity for the individual compressors providing service air and main control air usually lie in the range

of 400-700 scfm.

Smaller control air compressors are used in some plants to provide

air to isolatable segments of the control air system that serve the more

vital control applications. These compressors are configured to operate

only upon degradation of the main control air system, and often have

capacities ranging from 10 to 80 scfm.

BWR plants frequently have separate drywell control gas systems in

which small compressors take their suction from the drywell and supply

the control devices located within the drywell. In this way, leakage
5

from the air system does not introduce oxygen into the inert drywell

atmosphere or cause buildup of drywell pressure.

Typically, two or more compressors, any one of which can provide

normally required system capacity, are installed in parallel to ensure

uninterrupted service in the event of malfunction of one of the units.

One machine is usually assigned -the lead role, operating. continuously

while meetingfluctuations in system capacity requirements by means of

an unloading system that varies output in response to system pressure.

The second machine is assigned an automatic standby role, ready to start

if the lead machine cannot maintain system pressure. Additional

machines, if installed, are available for use if the lead orstandby

unit is down for maintenance or repair.

Other air and gas compressors are used for the following applications in various powerplants. These compressors are outside the scope

of the present assessment.

1. Emergency diesel generator start air. In a Pacific Northwest

Laboratory study of aging of nuclear station diesel-generators,

start air compressors were found to cause only one percent of diesel

generator failures. Brookhaven National Laboratory found that head

gaskets for these compressors have a service life of approximately

six years. --

2. Waste gas compressors which compress radioactive waste gas into

decay tanks.

3. Control room compressors which ensure a reliable air source for

environmental control under accident conditions.

4. Penetration pressurization compressors which provide positive buffer

pressure between containment isolation valves and in weld channels

in the containment liner.

5. Recombiner compressors which force radiolytic gasses through the

recombiner.

6. Pumpback compressors which maintain desired differential pressure

between the drywell and the torus in BRs.

7. Miscellaneous compressors-which provide control air at remote locations, such as raw cooling water intake facilities and cooling

towers.

8. Refrigeration compressors which are a part of various HVAC systems

and ice-bank pressure suppression systems.

Compressed air leaving the compressor aftercooler is warm and saturated with water vapor. Without drying, condensation in distribution

piping and in the control devices themselves would occur during subsequent cooling to ambient temperature. All control air systems use air

dryers located between the compressors and the distribution piping to

lower the pressure dew point, defined as the dew point of the air at

system pressure, to a level below any temperature encountered in the

system piping or using equipment. The dryersare either refrigerated or

desiccant types. The dryers often are installed with two units in parallel to provide redundancy for maintenance outages.
6

2.2 Compressors

2.2.1 Compressor Types

Service and control air compressor usage in each U.S. nuclear power

plant, as described in safety analysis reports and other licensing documentation, is presented in Appendix A. Although the documentation is

not specific as to equipment description in many cases, sufficient description is provided for the majority of the plants to permit determination of a fairly complete pattern for the use of different types of compressors and dryers. Incidence of use of the various compressor types

for each application is summarized in Table 2.1. Of the types specified, reciprocating compressors are the most widely used of all types

Table 2.1. Incidence of use of various compressor

types in U.S. nuclear power unitsa

Non- Oil Not Application and type lubricated lubricated specified

Service air

Reciprocating 42 4 12

Centrifugal 8 - 9

Screw 3 4 5

Liquid seal rotary 1 - -

Unspecified 9 4 29

Main control air

Reciprocating

From service air 30 - 3

Dedicated 24 - 6

Centrifugal

From service air 8 - 5

Dedicated - - 2

Screw

From service air 3 - 4

Liquid seal rotary

Dedicated 1 - 2

Unspecified

From service air 6 - 6

Dedicated 7 - 7

Miscellaneous control air

Reciprocating 18 - 3

Liquid seal rotary 1 - 2

Diaphragm - - 1

Unspecified 8 1 15

aAs described in licensing documentation for 123 reactor

units.
7

for providing service and control air, with nonlubricated or oil-free

machines utilized for control air and either nonlubricated or oillubricated machines for service air.

Other types of compressors used in service and control air applications include oil-lubricated' rotary screw, nonlubricated rotary screw,

oil-free centrifugal, and liquid-seal rotary. Because of the relatively

low incidence of use of these types, they are not included in this

assessment.

Reciprocating compressors are usually double-acting, with compression occurring during both directions of piston movement. This results

in a smaller machine for given capacity and provides a lower level of

pulsation in the delivered air stream. Both single-stage and two-stage

reciprocating compressors are used in service and control air applications. Two-stage compressors have water-cooled intercoolers between the

two stages and provide lower discharge temperatures and higher efficiency. Aftercoolers followed by moisture separators are used with both

single-stage and two-stage machines to cool the exiting compressed air

and remove excess moisture. As a result, the air leaving the moisture

separator is warm and saturated with water vapor.

A single-stage nonlubricated reciprocating compressor is shown

schematically in Fig. 2.1. The running gear, consisting of the main

frame and crankcase, crankshaft, connecting rod, crosshead, and oil

wiper is identical to that of an oil-lubricated compressor. A filtered,

force feed lubrication system supplies oil to the main bearings, the

crankpin and crosshead pin bearings, and to the crosshead. The crosshead design absorbs side thrust from the crank-connecting rod mechanism

ORNLDWG 90-3737 ETD

OILWIPER

DISTANCE PIECE DISCHARGE

\ hi c~TROD PACKING 

: /1 ISOROD/ _

/ ACROSSHEAD L OIL STOP

/ LCONNECTING ROD Say

Z-cRANKsHAFr

/o /'-RIDER RING

/ '-COMPRESSION RING (MP.)

Fig. 2.1. Nonlubricated reciprocating compressor schematic.
8

and results in only axial forces and movement in the piston rod. The

oil wiper prevents excessive oil migration from the running gear via the

piston rod.

In the nonlubricated machine, the lengths of the distance piece,

which connects the running gear frame to the compression cylinder, and

the piston rod are adequate to assure that no point on the piston rod

passes through both the oil wiper and the rod packing. In addition, an

oil-stop baffle plate is installed on the piston rod between the oil

wiper and rod packing to prevent oil migration along the rod.

The self-lubricating rod packing consists of segmented rings of

carbon or tetrafluoroethylene (TFE), surrounded by garter springs, and

contains system pressure. Self-lubricating compression rings and the

broad rider ring, which supports the piston weight and prevents metalto-metal contact, are made of TFE.

Nonlubricated reciprocating compressors are available from several

manufacturers. Although the details of design differ with manufacturer

and model, the basic principles of design and operation can be illustrated by reference to a single manufacturer and model. For this purpose, information for an Ingersoll-Rand Model PHE compressor is presented.7 The Model PE is a two-stage, horizontally opposed, machine

having a 6-in stroke. Through the choice of low- and high-pressure cylinder bores and operating speed, it is available with rated capacities

of from 409 to 667 actual cfm at a delivery pressure of 100 psig.

A cross-sectional view of the low-pressure cylinder is shown in

Fig. 2.2, and a view of the high-pressure cylinder is shown in

Fig. 2.3. The cylinder walls, heads, and rod packing region are cooled

by water flow through the surrounding water jackets. In the lowpressure cylinder, suction and discharge valves are installed radially

in each end of the cylinder. Valves in the high-pressure cylinder are

installed in port plates that are parts of the head assemblies.

Details of the low-pressure cylinder valves are shown in Fig. 2.4.

Design of the high-pressure valves is similar. The function of each

valve is that of a spring-loaded check valve, with the spring-loaded

valve channels lifting from the slotted seat plate, in response to pressure differential, to permit flow in the desired direction. Wear and

friction are minimized by the use of TFE channel guides and spring wear

strips.

The compressor accommodates variations in capacity requirements by

means of unloaders that raise the suction valve channels off the seal

plates in both the low-pressure and high-pressure cylinders. Staged

half-capacity unloading or full unloading may be accomplished by opening

either the valves on one end or on both ends of each cylinder. The

unloaders are pneumatically operated, via a regulator that senses

receiver pressure. A solenoid air valve is used to apply air pressure

to the unloaders, thereby unloading the compressor, during startup.
9

Fig. 2.2. Cross-sectional view of low-pressure cylinder. (From

Ref. 7, by permission).

Fig. 2.3. Cross-sectional view of high-pressure cylinder. (From

Ref. 7, by permission).
1(

ORNL-DWG 90-3740 ET

INLET DISCHARGE

Fig. 2.4. Typical inlet and discharge channel valves.

Ref. 7, by permission).

(From

The compressor is driven either by a frame-mounted, directconnected, motor or by V-belt drive from a separate motor. Usually,

protective circuitry stops the motor on high cooling water outlet

temperature, high outlet air temperature, high outlet air pressure, or

low running gear oil pressure. A time-delay relay bypasses the low oil

pressure switch and unloads the compressor for approximately 10 seconds

during startup.

The intercooler, shown in Fig. 2.5, is a water-cooled shell-andtube heat exchanger with provision for separating and automatically

draining condensate. Admiralty brass tubes are used. The inside

surface of the steel shell is coated with neoprene to retard rust. A

filter in the air discharge line protects the high-pressure stage from

any scale or particulates that may build up in the shell. A solenoid

valve is often used in the cooling water supply to both the cylinder

water jackets and the intercooler to interrupt water flow when the compressor is idle, thereby reducing any tendency for internal or external

moisture condensation during idle periods.
11

ORNL-DWG90-3741 ETD

POP SAtETY

INTERCOOLER SHELL

1llI

E HALF

COUPLINGS

SPACER

HEAD I

INSIDE

TUBE PLATE

AIR I

GAUGE a

kTE

* 4- CONDENSATE TRAP

x"x # (, 

Tit

OUTSIDE

TUBE PLATE

OUTSIDE

WATER HEAD

GASKET

PLATE

SIDE I INTERNAL

NEAD WRENCHING NUTS

Ref. 7, by permission). Fig. 2.5. Intercooler. (From
12

2.2.2 Compressor equipment boundaries

For purposes of this report, the compressor is defined to include

the following.

1. The main frame and running gear, including all internal parts.

2. The compression cylinders, including piston rods, rod packings,

pistons and rings, valves, and unloaders.

3. The intercooler, in two-stage equipment.

4. Belt drive.

5. Protective circuitry.

Electric motors are not included in this assessment; they are included as another element8 of the NPAR program.

2.2.3 Compressor functional requirements

The compressors, serving either as lead units or backup to the lead

units, are required to provide highly reliable sources of compressed air

for all plant uses. Required capacities are dependent on specific

application, as shown in Appendix A. Delivery pressure is usually in

the 100-125 psig range. Compressors providing control air are usually

required to deliver oil-free air.

2.2.4 Compressor materials of construction

The materials of construction, as provided in catalogs by three

manufacturers of nonlubricated reciprocating compressors (IngersollRand, Joy, and Worthington), are listed in Table 2.2.

2.3 Dryers

2.3.1 Dryer types

Refrigerated and desiccant type dryers are used in the control air

systems of nuclear power plants. In a few cases, combination refrigerated/desiccant dryers are used, with the refrigerated section preceding the desiccant section to remove a large fraction of the excess moisture and thereby lower desiccant loading.

Refrigerated dryers cool the air stream to condense out a fraction

of the contained water vapor, separate the condensed moisture, and then

reheat the leaving air stream. Achievable pressure dew point can be no

lower than a few degrees above the freezing point if ice formation in

the dryer is to be avoided.

A refrigerated dryer is shown schematically in Fig. 2.6. Entering

air is cooled in a regenerative shell-and-tube heat exchanger by the

leaving air, with an appreciable fraction of the total moisture removal
13

Table 2.2. Compressor materials of construction

Component Ipgersoll- Joy Worthington Rand

Kain frame

Crank shaft

Connecting rod

Kain bearings

Crank bearings

Crosshead

Piston rod

Rod packing

L.P. piston

Cast iron

Forged steel

Forged steel'

Full-floating

aluminum

Full-floating

aluminum

Aluminum

Hardened steel

TFE

Aluminum

Aluminum

TFE

Cast iron.

Not used

Stainless -steel

Stainless steel

Cast semi-steel

Not specified

Forged steel

Spherical roller

steel

Steel-backed

copper-lead

Tin-faced

cast iron

Chrome-plated

hardened steel

Carbon

Nickel-plated

cast iron

Nickel-plated

cast iron

TFE

Cast semi-steel

Flame-sprayed 420

stainless on cast

iron

Stainless steel

Not specified

Cast iron

Nodular iron

Nodular iron

Double roller

steel

Babbitt-lined

steel

Babbitted

cast iron

Hardened steel

H.P. piston

. , .~

Rings

Cylinders 

Cylinder liner

TFE

Aluminum

Cast iron

TFE

Cast iron

Not used

Stainless steel.

Nodular iron -

Valve elements

Valve seats

DRYAIR 4

ORNL-DWG 903742 E1D

MOISTUJRE

SEPARATOR~

Fig. 2.6. Refrigerated air dryer schematic.
14

occurring in this heat exchanger. The air stream then flows to the

chiller, where it is further cooled by evaporating refrigerant and additional moisture is condensed. The cold air and condensed moisture then

passes through a centrifugal moisture separator, where the moisture is

separated and removed via a trapped drain. The air stream, now saturated with moisture vapor at low temperature, then flows through the

regenerative heat exchanger, where it is warmed by the incoming air.

The leaving air dew point is controlled by the refrigerant thermostatic

expansion valve setting. During low air flow conditions, hot refrigerant gas from the compressor discharge is added to the cold, lowpressure, refrigerant leaving the expansion valve by the hot gas bypass

valve. This is done to limit minimum chiller temperature, preventing

ice formation under the lightly loaded conditions.

Desiccant dryers pass the air stream through a column filled with

granular desiccant material. Moisture in the air is adsorbed onto the

desiccant in passage, resulting in a typical discharge pressure dew

point of -40'F. The moisture-holding capability of the desiccant is

limited, and means of regeneration must be provided. To provide for

continuous drying service, dryers are constructed with two desiccant

columns, with valving to permit one column to regenerate while the other

is in active service. The regeneration process is automated, with a

cycle timer controlling initiation and termination of regeneration.

One of two processes is used to regenerate the moisture-laden column. In the heat-regenerated process, a relatively small stream of air,

electrically heated to approximately 400'F, flows in reverse direction

through the regenerating column to remove the adsorbed moisture from the

desiccant. The air then either is exhausted or is recirculated through

a cooler/moisture separator and back to the heater by a small blower, as

shown schematically in Fig. 2.7. Heat-regenerated dryers normally operate on an active-regeneration cycle of several hours duration.

In the heatless regeneration process, a relatively small stream of

air from the exit of the active column is reduced in pressure and passed

in reverse direction through the regenerating column. Moisture is retrieved from the desiccant by the low-humidity air, driven by the heat

of adsorption remaining in the desiccant from the active phase of operation. A heatless dryer is shown schematically in Fig. 2.8. Heatless

dryers typically operate on a much shorter active-regeneration cycle,

usually only a few minutes in duration.

Desiccant dryers are protected from entrained free moisture and oil

in the incoming air by prefilters. These filters use either ceramic or

fiber elements to coalesce and drain off incoming liquid and to trap

solid particulates, thereby preventing contamination of the desiccant

material. Prefilters are not used universally for refrigerated dryers

because incoming contaminants are collected and removed by the condensed

moisture. Afterfilters are always provided for desiccant dryers, to

trap any desiccant that may be carried from the dryer by the exiting dry

air. Afterfilters are usually provided for refrigerated dryers to trap

particulates and any entrained moisture or oil.
15

ORNL-DWG 903743 ETD

,' I I

4-WAY VALVE

MOIST AIR

Fig. 2.7. Heat regenerated dryer schematic.

ORNL-DWG 90-374 ETD

COLUMNA 

(REGENERATING)

COLUMNW

(ACTIVE

MOST AIR

Fig. 2.8. Heatless dryer schematic.
16

Air dryer usage in each U.S. nuclear power plant, as described in

safety analysis reports and other licensing documentation, is presented

in Appendix A. Dryers are specified for the control air systems for all

of the 114 reactor units having compressed air systems described in the

documentation. The number of units using each of the various dryer

types is shown in Fig. 2.9. Because some units use more than one type

of dryer, the total for all types is greater than the number of units.

Of the 114 units for which information is provided, 103 use desiccant

dryers. Heat-regenerated and heatless types of dryers share almost

equal status among the units for which type of desiccant dryer is specified; however, the large number of units having desiccant dryers without

specified type (shown as Regen." in the figure) prevents meaningful

conclusions regarding the relative incidence of use of the two types.

Similarly, the lack of specificity as to desiccant used (type of desiccant is only specified for one-quarter of the units using desiccant

dryers) precludes determination of the relative use of silica gel and

alumina.

ORNL-DWG 90-3745 ETD

|ZII ALUMINA SILICA GEL UNSPECIFIED

60

52

50

40

0 30l - 24 4 2

02 i "R 

z ~~~413

.... ...! /....

10 K t4 t7

HT. REGEN. HEATLESS HEUEN. ItFHIGEH. COMBIN. UNSPEC.

DRYER TYPE

Fig. 2.9. Units using various types of air dryers.
17

2.3.2 Dryer equipment boundaries

For purposes of this report, the air dryer is defined to include

the following.

1. -For the refrigerated dryer:

a. -The refrigerant circuit equipment, including the compressor, the

-condenser, the evaporator (chiller), the expansion valve, the

hot gas bypass valve, and associated controls.

b. The regenerative air-to-air heat exchanger.

2. For the desiccant dryer:

a. The desiccant-containing columns, including desiccant support

structure and screens and the desiccant material.

b. The air flow control valves and associated piping.

c. The regeneration heater, cooler-separator, and blower, if used.

d. The regeneration cycle control system.

e. The prefilters and afterfilters.

2.3.3 Dryer functional requirements

The air dryers are required to provide a reliable supply of lowhumidity air to the control air systems. System pressure is nominally

100 psig and dryer capacity is selected to meet system requirements.

Refrigerated dryers are required to provide discharge air dew point, at

pressure, in the range of 34-390F. Regenerative desiccant dryers,

either heatless or heat-regenerated, usually are required to provide

-40'F discharge dew point.

2.3.4 Dryer materials of construction

Desiccant tower vessels are fabricated from carbon steel. Desiccant support screens are stainless steel. Main air piping is carbon

steel. Valve bodies are usually steel, with stainless steel internals in

some models. Valve control air piping is often copper. Desiccant is

silica gel or activated alumina.

In refrigerated dryers, the shells of the regenerative air-to-air

heat exchanger and the chiller are carbon steel. Heat exchanger tubing

in both of these components is admiralty brass or copper.
13

3. TECHNICAL SPECIFICATION REQUIREMENTS

The Technical Specifications for each nuclear power plant establish

requirements for surveillance testing of safety-related components to

demonstrate operability of the components within specified limits. Compressed air systems are not usually considered to be safety-related

because operation of these systems is not required to bring the plant to

a safe shutdown condition. Therefore, the air systems are not usually

referenced in the Technical Specification.

Plant service and main control air systems are required for startup

and normal plant operation. Thus, their performance capability is

demonstrated in the course of normal operation. Standby and emergency

compressors are tested periodically to demonstrate their operational

readiness if needed.
19

4. SUMMARY OF OPERATIONAL STRESSORS

In this section, the compressors and dryers are divided into subcomponents and parts and -the significant stressors acting upon these

parts are identified qualitatively under normal and accident conditions.

Stressors have been divided into six categories: electrical, mechanical, thermal, chemical, radiation, and environmental.

Plant service air compressors and compressors and dryers providing

main control air are usually located in the turbine building or the

auxiliary building. They therefore are exposed to an environment not

significantly different from that in normal industrial practice.

Smaller compressors and dryers serving to provide in-containment or

emergency control air supply may be located within or adjacent to containment and can be exposed to a much harsher environment, especially

under accident conditions. Although not normally expected to operate

under accident 'conditions, some refurbishment may be required following

an accident.

4.1 Compressors

4.1.1 Electrical stressors

4.1.1.1 Drive motor. An aging assessment of electric motors is

reported in Ref. 8.

4.1.1.2 Protective switches. Protective switches used to detect

and signal abnormal temperatures and pressures experience some arcing

upon opening and closing of contact points, resulting in degradation of

the contacts due to local vaporization of contact material. In addition, heat generation by the arcing and resulting increased contact

resistance can affect the switch parts susceptible to thermal age

degradation. Because 1) the current carried by these switches is small,

2) the frequency of switch actuation is low, and 3) Arrhenius aging data

of polymeric materials normally used for insulating and structural parts

in the switches indicate slow aging under normal conditions, switch

degradation under normal conditions should not be a major factor in the

aging characteristics of the total machine.

4.1.1.3 Solenoid valves. Solenoid valves are used to unload the

compressor during startup and to stop the flow of cooling water when the

compressor is idle. Aging characteristics of solenoid valves were

assessed in Ref. 9.
20

4.1.2 Mechanical stressors

4.1.2.1 Running gear.

Main frame. The main frame serves to contain the lubricating oil, to

support the static and dynamic loads imposed by the stationary and

moving parts of the compressor, its drive system, and external piping,

and to maintain the spatial relationships of the various parts of the

compressor. Due to the robust design, the frame is competent to withstand the imposed loads over a long operating lifetime.

Main bearings and seals. Main bearings, which support the rotating

crankshaft, either rolling element or hydrodynamic type, are stressed

primarily by dynamic loads due to inertial forces from the reciprocating

parts and the air forces on the piston faces. Rolling element bearing

mechanical stressors include abrasion by dirt and wear particles in the

lubricant, lubricant degradation, and surface fatigue from Hertzian contact stresses. Mechanical stressors for hydrodynamic bearings include

abrasion by dirt and wear particles in the lubricant, lubricant degradation, and metal-to-metal contact between moving and stationary parts

before the hydrodynamic film develops during startup. Elastomer seals,

which prevent lubricant leakage and ingress of dirt, are subject to wear

and to material properties deterioration with age.

Crankshaft. Mechanical stress in the crankshaft results from the transmitted torque and bending loads imposed by the drive system and cyclic

forces from unbalance, inertial loads from the reciprocating parts, and

work on the air being compressed. The main journals, in those machines

using hydrodynamic main bearings, and the crank journals are exposed to

tribological stressors, especially during startup. As in the case of

the main frame, the robust design of the crankshaft provides competence

to withstand the imposed mechanical stress. During normal operation,

the journals are pressure-fed with filtered oil. During startup, the

compressor is unloaded to reduce drive system and bearing loads. As a

result, mechanical stressors on the crankshaft should not be a major

factor in machine aging.

Connecting rod. Mechanical stress in the connecting rod results from

cyclic compressive and tensile loading from gas forces and inertial

forces of the reciprocating parts and cyclic bending forces due to inertial forces of the connecting rod itself. The connecting rod is normally capable of withstanding these stresses over a long lifetime.

Metal-to-metal contact in the crankpin bearing is prevented during

normal operation by well-developed lubricant hydrodynamic film pressure

and by squeeze-film pressure. The crosshead pin bearing, because of its

oscillatory motion, depends upon squeeze-film pressure alone. Lubrication of both bearings is adequate to minimize tribological stress during

normal operation. At startup, only boundary lubrication by lubricant

remaining in the bearing clearances exists and wear during this brief

period may be significant.
21

Crosshead. The crosshead serves to convert forces collinear with the

instantaneous axis of the connecting rod to forces collinear with the

compressor cylinder axis' With a short connecting rod, the side forces

on the crosshead are appreciable during piston mid-stroke. Lubricant is

pressure-fed to the crosshead sliding surfaces via drilled passageways

through the crankshaft and connecting rod, thereby minimizing wear even

though a hydrodynamic film does not develop fully. Again, lubrication

during startup is marginal, with some wear to be expected during this

phase of operation.

Oil wiper. The oil wiper serves to prevent excessive lubricant loss

from the crankcase via the reciprocating piston rod. It consists of two

or more metallic rings, which are segmented to accommodate some amount

of radial wear while maintaining a close fit to the piston rod. Carter

springs maintain radially inward pressure on the segments. The rings

are lubricated by oil wiped from the piston rod surface. Wear of the

wiper rings is expected; the rings are replaceable.

Belt drives. The V-belts used on a compressor that is belt-driven tend

to assume a permanent "set", which can lead to premature belt failure,

if the machine sits idle for a long period of time. Belts wear from

contact with the sheave groove faces and from flexing, and periodic

adjustment and replacement is expected.

4.1.2.2 Cylinder/Piston Assembly.

Piston rod. The piston rod transmits linear motion from the crosshead

to the piston, while reciprocating through the oil wiper and the rod

packing. Cyclic compressive and tensile stresses are imposed by gas

forces and inertial forces from the reciprocating piston. Tribological

stresses are imposed on the rod surface zones that pass through the oil

wiper and the rod packing.

Rod packing. The rod packing seals the compressed air in the inboard

compression chamber of the cylinder from the atmosphere. The packing

consists of a series of TFE or carbon rings, segmented and radially

loaded by garter springs to accommodate wear where the rings contact the

reciprocating piston rod. The primary stressor is tribological. Wear

is expected; the rings are replaceable.

Piston rider and compression rings. The piston rider ring is a broad

TFE ring, contained in a circumferential groove midlength in the piston,

that supports the weight of and centers the piston in the cylinder bore,

thereby preventing metal-to-metal contact between the piston and cylinder. The primary stressor is tribological, with only the selflubricating property of the ring material to provide acceptable wear

rate.

The compression rings are relatively narrow TFE rings, contained in

circumferential grooves near the two ends of the piston. These rings

seal the piston to the cylinder bore to minimize blowby of high pressure

air during the compression stroke. Adequate sealing even with a limited
22

amount of radial wear is accomplished by a spring expander ring or by

gas pressure that bears on the inside bore of the ring. As with the

rider ring, the primary stressor is tribological.

Rider and compression ring wear is expected; they are replaceable.

Wear rate is greatly accelerated by deterioration of the cylinder bore

due to corrosion or by particulate matter in the incoming air. One

manufacturer attributes a large fraction (90%) of the troubles with nonlubricated compressors to dirt and rust entering with the intake air and

recommends that intake lines should be of a noncorroding material.10

Cylinder and heads. The cylinder and heads assembly provide the compression chambers, air flow passages, cooling water jacketing, mountings

for the rod packing and valves, and connection points for external

intake, discharge, and cooling water piping. Mechanical stressors

include the mechanical stresses imposed by external piping loads, by

vibration, and by the contained air pressure, and tribological stress

from interaction with the reciprocating piston rings. Gasketted joints

and their attendant fasteners are under continual mechanical and fluid

stress, with relaxation through creep possibly causing air or water

leaks.

Valves. The suction and discharge valves close at essentially zero

flow, when the piston is at the extremes of the stroke and has zero

velocity. As a result, closing is a gentle process with little impact.

Suction valves open when piston velocity is approximately half maximum

velocity and discharge valves open when the piston is essentially at

maximum velocity, resulting in rapid movement of the moving valve parts

during opening. Design features often are provided to cushion the opening action, either by springs or air cushioning, to prevent the valve

channels (or strips or disks in other designs) from slamming against the

valve stops. TFE inserts and guides are used as needed to prevent

metal-to-metal wear of valve parts. Mechanical stressors include

fatigue-inducing stresses in springs and sealing elements and erosion of

the sealing surfaces from particulates in the air.

4.1.3 Thermal stressors

Elevated temperatures exist in the compressor, due to viscous friction in the running gear lubricant and to the compression process,

during normal operation. Normal crankcase oil temperature is approximately 50'F above ambient.7 Discharge air temperature from a singlestage, 100 psig, compressor is approximately 410'F, while a two-stage

machine will have low-pressure and high-pressure stage discharge temperatures of approximately 225'F and 270'F, respectively. The materials

of construction are compatible with these temperature levels; thermal

stressors are not a significant factor in compressor aging.
23

4.1.4 Chemical stressors

Chemical tressors for compressors are limited to running gear lubricant deterioration and corrosion of the highly polished rubbing surfaces of the piston rod and the cylinder bore. Condensation of water in

the crankcase can cause sludge formation and breakdown of the lubricant

properties. Condensation of water in the cylinder and in the rod packing area during idle periods can cause deterioration of the surface

finish, with subsequent accelerated wear of the packing or rings. Condensation is exacerbated if water'flow to the cooling jackets is allowed

to continue during idle periods. Exposure of in-containment compressors

to high humidity during accident and post-accident conditions could also

result in corrosion damage.

4.1.5 Radiation stressors

Compressors are normally installed in areas of low radiation exposure. This, coupled with the insensitivity of the materials of construction, should prevent any significant aging effects from radiation

stressors.

4.1.6 Environmental stressors

Possible environmental stressors include dirt and high humidity in

the inlet air and silt, biological organisms, or high mineral content in

the cooling water. Ingestion' of particulate material in the suction

airstream would cause accelerated wear of piston rings and the cylinder

bore. However, the compresors and their air intakes are usually

located in relatively clean areas, and the intakes are equipped with

particulate' filters. High'ambient humidity promotes condensation and

subsequent corrosion in idle machines; it is also deleterious to idle

beltt drives. Poor cooling water quality can cause impaired cylinder

cooling due'to scale formation or flow blockage.

4.2 Dryers

4.2.1 Electrical stressors

Electrical components of refrigerated dryers include the refrigerant compressor drive motor, the compressor crankcase heater, low suction

pressure and high discharge pressure cutout switches, dryer on-off

switch and contactor, and miscellaneous indicator lamps. These components have widely-used counterparts that have demonstrated long lifetimes

in all parts of the refrigeration industry. Actuation of the various

switches is relatively infrequent and point degradation in the switches

due to arcing should be minor. No appreciable aging effects due to

electrical stressors are expected.
24

Electrical components of heatless desiccant dryers include the air

flow control solenoid valves and the regeneration cycle sequence controller. Heat-regenerated dryers additionally have resistance heaters

with associated temperature controller and, if closed-cycle, the recirculation blower drive motor.

An assessment of aging of solenoid-operated valves was reported in

Ref. 9. Frequent cycling, as is the case for the control valves in

heatless dryers where cycling periods of a few minutes are used, was

pointed out as an abnormal stressor. Long-term energization of the

coil, causing elevated coil temperatures especially where ambient temperature is high, was listed as as a significant stressor. However, the

dryers are normally located in areas that do not have high ambient temperature, and although heat-regenerated dryer valves may be energized

for several hours during the long regeneration cycle, high coil temperatures should not be a significant factor in the aging characteristics.

4.2.2 Mechanical stressors

The desiccant chambers are pressure vessels that undergo cyclic

pressurization/depressurization and temperature changes during the

active/regeneration cycles. Tensile and thermal stresses induced by

these actions are the principal mechanical stressors for these components.

Frequent cycling of the air flow control valves, especially in

heatless desiccant dryers, causes cyclic stresses and wear in the valve

seats. Certain of the valves control the flow of air that may contain

particles of desiccant, leading to erosive wear and possible sticking of

the valve parts.

The desiccant itself is exposed to mechanical stress due to air

flow. If repressurization, prior to resumption of active drying, and

reestablishment of air flow as the active drying phase begins in a given

chamber is abrupt, the desiccant may be levitated. This action results

in particle degradation with dust generation and, ultimately, in

impaired performance of the dryer.

4.2.3 Thermal stressors

Heat-regenerated desiccant dryers expose the desiccant to air temperatures of 400 to 550'F during the regeneration process. The desiccant does not suffer significant physical degradation due to these temperatures, but a loss of moisture retention capability may occur with

time due to hydrocarbon impurities, such as oil vapor, baking onto the

surface of the desiccant during regeneration.

4.2.4 Chemical, Radiation, and Environmental Stressors

There are no significant chemical, radiation, or environmental

stressors that would cause accelerated aging of the air dryers.
25

5. OPERATING EXPERIENCE

5.1 Information Sources

Aging information for compressors and dryers was obtained from

various sources 'of nuclear power plant operating experience documentation. These include Licensee Event Reports (LER), Nuclear Power Experience (NPE), In-Plant Reliability Data System (IPRDS), and maintenance

records made available by a cooperating utility.

A summary of compressor and dryer problems delineated in LERs

issued between 1978 and August, 1988, as identified from a search of the

Sequence Coding and Search System (SCSS) maintained by ORNL's Nuclear

Operations Analysis Center and supplemented by a manual search for the

years 1978 and 1979 which are not included in the SCSS, is included in

Appendix B. LERs are issued by plant operating utilities to inform the

NRC of plant events having significant safety implications. Because

compressed air systems are not usually considered safety-related systems, LERs are issued only for those air system problems that are precursors to safety-related events, such as reactor trips or actuation of

Engineered Safety Features. As a result, the data base of LERs presents

a far-from-complete portrayal of compressor and dryer problems

encountered in plant operation.

Nuclear Power Experience, published by Stoller Power, Inc., is a

compilation, derived from several sources, of operating experience in

light water reactors. Summaries of events related to compressors and

dryers not included in the LER data base that were detected in a search

of the NPE data base are included in Appendix B.

The In-Plant Reliability Data System is a data base derived from

detailed plant maintenance records provided by a cooperating utility.

The plant for which the data was provided has a single boiling water

reactor and utilizes three nonlubricated reciprocating compressors for

service and control air and a single dryer. The data base includes

information on each maintenance call, for scheduled preventative maintenance procedures and for response to perceived equipment problems.

Information included, in varying degree of completeness, for each call

includes the date, equipment identification code, the procedure or perceived problem, problem diagnosis, and corrective action. Information

pertaining to the service and control compressors and to the dryers is

summarized in Appendix C. Corrective maintenance calls and those few

preventative maintenance calls from which problems were discovered are

included.

A compilation of maintenance calls for the service/control and auxiliary air compressors and dryers for a second nuclear power plant was

obtained from another cooperating utility. This is a two-unit pressurized water reactor plant. Service/control air is provided by four large

nonlubricated reciprocating compressors and three desiccant dryers. In
26

addition, there are two smaller auxiliary compressors and dryers to provide essential uses in the event of loss of the service/control air system. Data included for each call is similar to that included in the

IPRDS records. This information is summarized in Appendix D.

It should be noted that the severity of problems reported in the

various data sources may be quite different. Compressor or dryer problems reported in the LERs and, in most cases, in the NPE compilation are

those that resulted in unplanned shutdown of the reactor or actuation of

the plant's Engineered Safety Feature systems. They represent, in some

cases, the result of aging effects that have not been adequately

detected by surveillance methods and corrected by timely maintenance.

Other problems occur as random, probably unpredictable, sudden failures

of various components.

Problems as reported in the IPRDS and utility plant maintenance

records, on the other hand, present a more accurate portrayal of aging.

Included here are the day-to-day problems encountered with the machines,

most of which are overcome by timely repair or reliance on redundant

equipment such that loss of air supply does not occur. Many of these

problems, if uncorrected, would result in a gradual loss of capability

of the machines to meet volume delivery requirements at system pressure

rather than a sudden and complete disablement of the unit.

5.2 Summary of Failure Modes and Causes

5.2.1 Compressors

Service/control and auxiliary compressor failures/problems reported

in the data sources described above and delineated in the appendices are

summarized by type of failure in Table 5.1. Information pertaining to

the large service/control compressors and the smaller auxiliary compressors for the utility plant are presented separately to illustrate differences in operating experience with large, continuously operating

machines and smaller, intermittent-service machines.

Belts. Belt failures reported in the LER and NPE data bases consisted of belts either breaking or being thrown off, rendering the compressor inoperable. Belt problems included in the IPRDS and utility

maintenance data bases were usually identified and corrected by belt

replacement or adjustment before loss of operability.

Controls. Control failures include pressure switch malfunctions

that prevent the compressor from starting on low pressure or cause short

cycling due to insufficient dead band, faulty operation of time delay

relays that keep the compressor unloaded during startup and that override the low-oil-pressure switch during startup, and spurious temperature or pressure signals. Control failures render the compressor

inoperable.
27

Table 5.1. Summary of Compressor Failures/Problems

Utility

Failure Type

LER NPE IPRDS Serv/Contr. Auxil. Total

Belts 2 1 12 0 5 20

Controls 4 1 9 3 7 24

Cooling 0 0 13 0 0 13

Heat Exchangers & Traps 3 0 7 8 2 20

Leaks 3 0 20 55 38 116

Low Output 2 0 0 0 0 2

Mechanical 1 0 14 19 24 58

Motor 1 0 4 0 0 5

Operational 2 4 1 0 0 7

Piston Rings 0 0 1 8 2 11

Seals & Packing 2 0 1 61 3 67

Valves & Unloaders I 1 25 48 8 83

Total 21 7 107 202 89 426

Cooling. Cooling problems occurred with the compressors used in

the plant covered by the IPRDS. This plant utilized well water containing sediment and dissolved minerals, resulting in scale buildup and

blockage in the cooling water passages.

Heat Exchangers and Traps. Two instances of aftercooler tube failures that resulted in injection of high pressure air into the service

water system, disrupting the operation of that system, occurred in one

plant. The failure was attributed to faulty fabrication technique

during manufacture. Tube leaks in the intercooler introduce cooling

water into the shell side of the cooler; small leaks can be accommodated

by the condensate trap. Trap problems include the trap sticking open,

with air loss to the drain system, and the trap sticking closed, with

buildup of condensate in the shell. Casket leaks of air or cooling

water to the environment also occurred in some cases.

Leaks. Leaks of air, water, or lubricating oil is the most common

problem for the compressors. In most cases, these constitute a nuisance

that is corrected by bolt tightening or regasketing. In two cases,

leaks resulted in a reportable event - one in which air was injected

into thy cooling water and a reactor trip occurred as a result of an

attempt to vent the water system, and another where a cover plate leak

released chromate to the environment.

Low Output. Two instances of reducaed compressor output, due to

unexplained cause, were reported by LERs. Low output can result from

wear or breakage of piston rings, rod packing, or intake or exhaust

valves or from malfunction of the unloaders.
28

Mechanical. Mechanical problems primarily are related to the running gear of the compressors, but also include conditions requiring a

general rebuild of the units. Only one mechanical failure, where the

piston rod detached from the crosshead because of a broken locking

washer in an auxiliary compressor while the backup compressor was down

for maintenance, resulted in issuance of an LER.

Other mechanical problems identified in the IPRDS and utility maintenance records include:

a. unusual noise during operation (cause unexplained in

13 instances, 3 due to crankshaft or connecting rod problems,

and 1 due to improper clearance adjustment);

b. low oil level or pressure (11);

c. broken components such as crankshaft (3), frame part (1), or

valve mounting bolts (1); and

d. need for rebuilding the compressor (13 instances where causes

were not identified, probably from worn internal parts, and

4 instances where water was found in the crankcase or in one of

the cylinders, probably from an internal cooling water leak or

from malfunction of the intercooler condensate trap).

A disproportionately large fraction of the mechanical problems with

the utility plant compressors, including all occurrences of a broken

crankshaft, were experienced in the two smaller auxiliary compressors.

These compressors are operated only during quarterly serviceability

inspections and in the event of loss of control/service air pressure in

containment. Long idle periods may result in accumulation of water in a

cylinder, either from condensation or small internal leakage, causing

lockup and damage during subsequent startup.

Operational. Operational problems are those that arise from the

imposition of improper operational requirements, rather than being

inherent problems with the compressors themselves. In one LER incident,

a centrifugal compressor surged and would not reload after a sudden

change in load when the air systems for two reactors were crossconnected. In another LER incident, a compressor tripped due to high

condensate level in the intercooler because of an improperly set trap

bypass valve. In an NPR-reported incident, a scram resulted when a

primary compressor tripped due to a faulty control and the backup compressor control was inadvertently in the "off" position. In three other

incidents, water or oil in the instrument air system resulted in air

system valve problems. Although not directly due to compressor malfunction, these incidents arose because of cross connection with the service

air system which may have been necessitated by instrument air compressor

problems. In an IPRDS-reported incident, a compressor would not load

automatically because a manual valve in the unloader circuit was found

to be closed when it should have been in the open position.

Piston Rings. No LER or NPE reports of piston ring problems were

found. Rings usually do not fail catastrophically but undergo continual

wear which is corrected by routine maintenance. Most of the maintenance
2q

calls for ring problems are found in the utility records for the large

service/control compressors that provide a continuous supply of compressed air. The paucity of ring problem reports in the IPRDS data

probably is due to routine ring replacement being accomplished during

preventative maintenance procedures; details of these procedures are not

available.

Seals and Packing. Two LERs resulted from seal failures - one from

the loss of seal water in a liquid-seal rotary compressor, and the other

from worn seals in the oil pump. The IPRDS data includes one seal problem, a worn oil seal on the crankshaft. Most of the seals and packing

maintenance calls from the utility records were for replacement of the

piston rod packing (49 calls for the four large compressors and 1 for

the two auxiliary compressors). Oil wiper replacement was called for in

10 calls for the large compressors and 2 for the auxiliary machines.

Two oil seal calls were recorded for the large compressors and none for

the smaller units. As in the case for piston rings, seals and packing

undergo gradual deterioration due to aging and wear and normally do not

result in sudden failure of the compressor.

Valves and Unloaders. Only one LER-reported incident and one NPEreported incident involved valve or unloader problems. In each case, a

backup compressor failed to load upon startup, in one case due to a

failed unloader system solenoid valve and in the other due to a sticking

unloader valve.

Valve and unloader problems accounted for more maintenance calls

(25) than any other compressor problem type in the IPRDS data. Seven

valve problem calls are listed, with most due to leaking or noisy valve

operation. In two cases, valves came loose from their mountings and

broke apart with pieces entering the compression chamber and scoring the

piston or cylinder wall. Unloaders were responsible for 18 calls, 14 of

which involved unsatisfactory operation of the solenoid valves that control the unloaders.

In the utility plant record of maintenance calls, valves and

unloaders tied with seals and packing for second ranking in number of

calls. For the four large service/control compressors, which collectively provide full-time compressed air service, valves were involved in

40 maintenance calls. Valve leaks, usually detected by blowback through

the intake filter or by abnormally high intercooler pressure, accounted

for 21 of the calls, and noisy operation accounted for another four.

One call each was due to a loose valve, broken mounting bolts, and a

broken valve. Valves were replaced in 12 calls that were initiated for

other causes, either due to possible damage from such events as water

leakage into the compressor or to consolidate maintenance activities

during other repairs.

The unloaders for the large compressors accounted for eight maintenance calls. Ambiguous references to components in the unloader

system prevent positive identification of the malfunction causes. The

records indicate a "stuck" unloader in four instances, a "bad" unloader
30

in one instance, and "control valve", "pilot valve", or "3-way valve"

problems in four instances. Rebuilding, cleaning, or unloader control

valve replacement were the reported corrective actions.

The two smaller auxiliary compressors included in the utility plant

records had a total of eight maintenance calls involving valves and

unloaders. Leaky valves were the problem in two instances, and valve

replacement was carried out in response to three calls for other events

such as water leaks or a broken crankshaft. Unloader problems accounted

for three maintenance calls; the records are inadequate to clearly

define the nature of the problems.

5.2.2 Dryers

Air dryer failures and problems, for the dryers associated with

service/control and auxiliary compressors, reported in the data sources

described above and delineated in the appendices are summarized by type

of failure in Table 5.2.

Table 5.2. Summary of Dryer Failures/Problems

Failure Type LERa IPRDS Utility Total

Controls 1 6 1 8

Desiccant and filters 6 4 7 17

Leaks 0 5 0 5

Operational 5 0 0 5

Valves 3 7 4 14

Water in system 3 0 0 3

Total 18 22 12 52

aIncludes two citations in IEIN 81-38 and one in

NPE.

Controls. One disruption of the compressed air system due to outof-sequence operation of the solenoid valves during maintenance was

reported in the LER data. The IPRDS data included five instances of

problems with control of the regeneration heaters and one instance of

malfunction of the high humidity alarm. A burned-out timer motor was

the only reported control problem in the utility plant data.

Desiccant and Filters. Five events reported in the LER data base

and one event in the IPRDS data base were due to desiccant carryover

into the instrument air system. It would appear that failure of the

afterfilter would be indicated in each of these events, possibly exacerbated by excessive dusting of the desiccant. Another LER event involved
31

a plugged afterfilter as a result of improper replacement of desiccant

in the dryer. The remaining problems reported in the PRDS and utility

plant data involve excessive pressure differential across either the

dryer chambers (degraded desiccant) or the filters (dirty filters), or a

call for desiccant replacement without explanation of the reason.

Leaks. There were five maintenance calls in the IPRDS data for

repair of leaks in various parts of the piping and valves system associated with the dryer. Leaks were not an identified problem in either

the LER or utility plant data.

Operational. The LER data included five operational problems that

resulted in reactor trips or actuation of ESF systems. These included

the failure -of a soldered joint in an air line due to piping impact during a maintenance operation, improper valve alignment during the restoration of a dryer to service, two cases where a refrigerated dryer froze

up due to misadjustment of the hot gas bypass valve, and one instance in

which a restricted purge air outlet resulted in water in the air system

due to poor regeneration of the dryer.

Valves. Valves accounted for a large fraction of dryer problems

included in each of the data sources. Two solenoid valve failures and

one 4-way switching valve failure were included in the LER data. The

IPRDS data included maintenance calls for two valve actuator linkage

problems, two 3-way valve problems, one purge regulator problem, one

valve sticking problem, and one solenoid valve problem. The utility

data included maintenance calls for two sticking purge valves, one call

to clean check valves which were dirty and would not seat, and one

undescribed valve problem requiring replacement.

Water in Air System. Three instances of water in the air system

were included in the LER data, reflecting either poor operation of the

dryers or operation of the system without the dryers being in service.

In one of these instances, water had entered the system during maintenance; no explanation was provided for the other two.

5.3 Frequency of Failures

5.3.1 Compressors

Data from which the frequency of compressor failures can be determined are not available from the information sources used in this

assessment. Events reported in the LER and NPE data bases, in which the

compressed air system is degraded to the point where a reactor trip

occurs or Engineered Safeguard Features are actuated, often represent a

series of compressor failures involving inoperability of both the primary and backup compressors. Thus, mean time between failures calculated from these data sources errs on the high side. Conversely, mean

time between failures determined from the maintenance call data from the

two utility plants err on the low side because most of the maintenance
32

calls are for correction of conditions that do not represent failures of

the compressors to perform.

The LER data base covers the time period of 1978 through August

1988. During this period, U.S. power reactors accumulated a total of

approximately 812 unit years of operation, 17 compressor-related LERs

were submitted, and an additional 5 NPE-reported events occurred. From

this, the mean time between failures of the compressor system (as

reported by LERs plus the NPE) is 36.9 reactor-years.

Mean time between maintenance calls as derived from the IPRDS data

base and the utility plant records are much shorter. Compressor maintenance calls data from IPRDS cover a period of about 5.7 years, approximately representing plant years 9 through 14.7, and include 107 calls.

The average time interval between calls, for the three service/control

air compressors, is approximately 19 reactor-days. The utility plant

data cover approximately 7.2 years of air system operation and include

197 calls for the large service/control compressors and 89 calls for the

smaller auxiliary compressors. The average time interval between calls

is about 13 plant-days for the large compressors and 29 plant-days for

the small compressors.

The numbers of maintenance calls occurring during each year represented by the IPRDS data are given in Table 5.3. Records for plant year

14 represent the first eight months of that year. There is no evidence

of an increase in frequency of calls with increasing plant age.

The numbers of maintenance calls occurring during each year represented by the utility plant data are listed in Table 5.4. Records for

Table 5.3. Chronology of Maintenance Calls

for IPRDS Plant Compressors

Plant Year 9 10 11 12 13 14

No. of Calls

Belts 3 0 5 1 2 1

Controls 1 0 3 1 2 2

Cooling 2 6 1 3 1 0

Heat Exchangers 3 1 0 2 0 1

Leaks 3 3 3 5 5 1

Mechanical 1 5 6 2 0 0

Motor 0 0 2 1 1 0

Operational 0 0 0 0 1 0

Rings 0 0 0 0 1 0

Seals & Packing 0 0 0 1 0 0

Valves & Unloaders 7 3 6 2 6 1

Total 20 18 26 18 19 6
33

Table 5.4. Chronology of Maintenance Calls

for Utility Plant Compressors

Plant year 1 2 3 4 5 6 7 8

Maintenance Calls for Large

Controls -

HXs and Traps 1

Leaks 3

Mechanical 3

Rings

Seals and Packing 1

Valves and Unloaders 7

Total 15

Maintenance Calls for Small

Belts

Controls

HXs and Traps

Leaks 3

Mechanical 1

Rings

Seals and Packing

Valves and Unloaders

Total 4

Compressors

1

1 1

9 5 '10

3 3 1

1

5 3 14

2 4 -9

21 15 36

Compressors.

2 1

1 '1

2 1

' 8 '5

2 5

4 1

- 18 4

, 9 6

' ,44 23 

2

14

2

2

14

9

43

1

2

2

5

2

2

2

5

3

10 5

7

1 1

2

8

4

1

2

5 5

2 4

1

., 1

2

7 14

1

2

1 1 1 3

10 16 14 22

plant year 8 represent the first eight months of the year. The high

incidence of. maintenance calls for the large compressors during plant

years 4 and 5 was due to problems with seals and packing. The high

incidence during -plant year 7 was due to increases in the number of

calls for seals and packing and for leaks. With the exception of these

problem categories, there is no obvious trend toward increasing maintenance requirements with plant age. These two categories represent

readily replaceable or repairable machine elements, with wear and timerelated deterioration expected.

There is no evidence of an appreciable increase in frequency of

calls with increasing plant age for the smaller auxiliary compressors.

5.3.2 Dryers

As was the case for compressor failures, mean time between failures

for dryers as determined from LER data errs on the high side because

only dryer failures that resulted in reportable events are included.

Similarly, mean time between failures calculated from the IPRDS and

utility plant maintenance data err on the low side because many of the

maintenance calls included in that data do not represent dryer failures

but are for correction of degraded component performance.
3V

During the time period between 1978 and August 1988 covered by the

LER data base, which represents approximately 812 reactor unit-years,

16 dryer citations are included in the LER, IEIN, and NPE data. From

this, the mean time between failures of the dryers is almost 51 reactoryears.

The IPRDS data for dryers cover a period of approximately 5.7 years

and include 22 maintenance calls. The resulting average time between

maintenance calls is about 95 reactor-days. The utility plant data

includes 12 dryer maintenance calls, occurring over a time period of

approximately 7.2 years, yielding an average time between maintenance

calls of about 218 plant-days.

The numbers of dryer maintenance calls occurring during each year

represented by the IPRDS data are given in Table 5.5. Although the

year-by-year number of calls fluctuate sharply, there is no indication

of increasing maintenance requirements with age.

Dryer maintenance calls occurring during each year represented by

the utility plant data are given in Table 5.6. The large number of

Table 5.5. Chronology of Maintenance Calls

for IPRDS Plant Dryers

Plant Year 9 10 11 12 13 14

No. of Calls

Controls 0 2 3 1 0 0

Desiccant & Filters 1 1 1 0 1 0

Leaks 0 1 1 0 3 0

Valves 1 0 4 0 1 1

Total 2 4 9 1 5 1

Table 5.6. Chronology of Maintenance Calls

for Utility Plant Dryers

Plant Year 1 2 3 4 5 6 7 8

No. of Calls

Controls 0 0 0 0 0 0 1 0

Desiccant Filters 0 0 1 1 0 0 3 2

Valves 0 0 0 0 0 0 1 3

Total 0 0 1 1 0 0 5 5
35

calls in plant year 7 was due primarily to the need to clean the

moisture.trap and replace the afterfilter elements in each of the.three

large dryers. A spate of-three valve problems in plant year 8 resulted

in the high total for that year. It does not appear that any inherent

increase in maintenance with plant age occurred.

5.4 Methods of Detection

*The principal method for detecting compressor and dryer problems in

the plants is by regularly scheduled system walkdowns by operations personnel. Other problems are detected by maintenance personnel working in

the vicinity of the equipment. Incipient problems are also found during

scheduled preventative maintenance procedures. Failures of the equipment that result in subnormal air system pressure or conditions that

endanger the equipment, such as high dryer eit humidity or low lubricating oil pressure in a compressor are automatically detected and

alarmed. No data.are available to establish the incidence of problem

detection by these various processes'.

ci
36

6. MANUFACTURER-RECOMMENDED AND USER-APPLIED MAINTENANCE AND

SURVEILLANCE PRACTICES

Instruction or maintenance manuals provided by the equipment manufacturers contain recommended inspection, maintenance, repair, and

replacement procedures. The frequency of these procedures is often not

fixed by the manufacturer, but is to be determined by the owner from

operating experience with the given installation.

Preventative maintenance procedures that include surveillance and

inspection guidance are developed by the plant owner for each equipment

item. These procedures are carried out on a regularly scheduled basis;

the schedule may be modified as operating experience is gained with the

installation.

The low frequency of serious problems with compressors and dryers,

as evidenced by the operating experience cited in Section 5, indicates

that these practices are effective in providing dependable service.

6.1 Manufacturer-Recommended Practices for Compressors

Recommended surveillance, maintenance, and inspection procedures

and schedules for nonlubricated compressors, as included in an

Ingersoll-Rand maintenance manual,7 are as follows.

Daily

1. Drain receiver or check operation of automatic drain trap.

2. Adjust cooling water flow so that leaving cooling water is 10-15'F

warmer than incoming air.

3. Check unloader control regulator and automatic devices.

4. Check oil level.

5. Drain intake piping (while unit is unloaded or shut down) as

often as necessary.

Every 4000 operating hours or at least once per year

1. Change crankcase oil.

On a regular schedule, as established by experience

1. Check for rider and compression rings wear. During initial operation, check at 50, 200 and 500 operating hours, then at 500-hour

intervals until approximate rate of wear is established. Pistoncylinder radial clearance must be greater than 0.005 inch at all

times to preclude damage from metal-to-metal contact.
37

2. Check frame lubrication system, intake valves and unloaders, discharge valves, and packing.

3. Test safety valves to assure that they are free and in operating

condition. Safety valves should be removed and calibration

checked at least once per year.

4. Clean intake filter.

5. Clean the crankcase breather and change the oil filter.

6. Inspect water jacket and coolant passages for cleanliness.

7. Inspect intercooler tubes for cleanliness.

8. Change intercooler filter.

9. Inspect drive belts for general condition and tension.

Other

The unit should be protected from corrosion during extended shutdown

or storage periods. Recommended protection measures for storage

include:

Removal and protected storage of the oil scraper rings and piston

rod packing.

Placing a small quantity of vapor phase corrosion inhibitor (VPI)

crystals in the compressor cylinders.

Placing bags of VPI in the compressor inlet and discharge openings

and sealing these openings.

Wrapping the piston rod and stuffing box with PI paper and sealing with waterproof tape.

Removal and protected storage of drive belts to prevent their

acquiring a permanent set that would greatly increase possibility

of failure on restart.

6.2 User-Applied Practices for Compressors

Preventative maintenance and surveillance procedures for compressors were obtained from the utility operating the plant for which maintenance records are summarized in Appendix D and discussed in

Section 5. The preventative maintenance procedures for the large

control/service compressors and the smaller auxiliary compressors are

summarized in Tables 6.1 and 6.2, respectively. In addition to these

formalized procedures, plant operating personnel conduct a walkdown of
3'3

Table 6.1. Preventative Maintenance Procedures

for Control/Service Compressors

No. Frequency Description

1 Weekly Visual inspection of compressor and related equipment.

Check oil level.

Check proper operation of drain traps.

2 2 months Change intercooler filter.

3 6 months Check rings and pistons for wear.

Check valves for wear.

Check gaskets for condition.

Check scraper rings for wear.

Check seal condition.

Check cylinder walls for wear.

Clean water inlets.

Change oil and oil filter.

Replace all parts and gaskets as needed.

Table 6.2. Preventative Maintenance Procedures

for Auxiliary Compressors

No. Frequency Description

1 12 weeks Serviceability inspection.

2 Annually Lubricate compressor drive motor bearings.

3 18 months Calibration and test of low-oil-pressure switch.

4 18 months Calibration and test of the compressor control time

delay relays.

5 18 months Similar to Procedure 3 for the control/service compressors. This procedure formerly was carried out

semiannually, but the interval was increased because

of the low accumulated run time for these compressors.
39

the compressor-dryer system and blow down the traps--on a once-per-shift

basis.

The auxiliary compressors, which operate in service only upon the

event of subnormal pressure in the control air system, undergo a

serviceability inspection every 12 weeks. In this inspection, the compressors are checked for proper lubricating oil level, for autostart

capability, and for ability to maintain system pressure.

6.3 Manufacturer-Recommended Practices for Dryers

Recommended surveillance, maintenance, and inspection procedures

for a heat-regenerated desiccant dryer are included in the installation,

operating, and maintenance instructions" obtained from a supplier.

Although this particular dryer relies on manual repositioning of the air

flow valves for switching from active to regeneration mode, the procedures are similar to those for an automatically switching dryer using

timer-controlled valves. The procedures are summarized as follows.

Daily

1. Monitor alarm lights. If an alarm light is lit, refer to Trouble

Shooting Guide.

2. Monitor all pressure and temperature gauges. At no time should

any temperature exceed 450F.-

A

Weekly

1. Check operation of drain system; entrained water in blower will

damage blades.

Monthly

1. Check amp draw on all three phases of the blower and the heater.

At six month intervals

1. Check dryer outlet pressure dewpoint.

Annually

1. Clean and inspect all valves, inspect blower bearings and performance, inspect desiccant bed for oil fouling or other deterioration.
40

6.4 User-Applied Practices for Dryers

Preventative maintenance and surveillance procedures for dryers

were obtained from the utility operating the plant for which maintenance

records are included in Appendix D and discussed in Section 5. In addition to these formalized procedures, a once-per-shift system walkdown is

performed by plant operating personnel. The procedures are summarized

in Table 6.3.

Table 6.3. Preventative Maintenance Procedures for Dryers

No. Frequency Description

Control/Service Dryers

1 6 months Inspect sample of desiccant for fine particles, wetness, and discoloration by oil. Replace if any of

these are present.

Disassemble and clean all check valves.

Blow down relief valves to assure they are not stuck.

Remove and clean muffler and blowdown limiter.

Remove prefilter elements and inspect for clogging or

moisture. Reinstall or replace if necessary.

Remove and clean moisture trap. Reinstall or replace

if necessary.

Remove afterfilter element and inspect for excessive

powder. Clean and reinstall or replace if necessary.

Inspect selector and purge valves for cleanliness and

proper operation. Replace if excessively worn.

Auxiliary Dryers

1 18 months Test and calibrate cycle timer.

Inspect desiccant and replace if badly broken up or

contaminated with oil.

Inspect and clean pilot operated valves and seats on

check valves. Replace if worn or damaged.
41

7. AGING MONITORING AND ASSESSMENT

Failure modes and causes along with associated inspection, surveillance, and monitoring aspects are addressed in this section. The discussion is based on information derived from manufacturers' manuals,

plant maintenance personnel, a U.S. Navy program dealing with serviceability of shipboard air compressors, and this study. The areas covered

are failure mode detection, cause determination, and identification of

parameters for degradation trending and incipient failure detection.

7.1 Failure Mode and Cause Determination

Failure mode detection is described in terms of currently used

parameters and methods; suggested additions are also included. Failure

cause determination embraces both methods for cause differentiation and

use of measurable parameters for detailed evaluation. Methods for differentiation are discussed in this subsection, while measurable parameters are discussed in Subsect. 7.2.

The compressors and dryers included in this assessment are not

normally considered as safety-related equipment and are not addressed in

plant Technical Specifications or covered in the ASME Boiler and Pressure Vessel Code, Sect. XI rules for inservice inspection. The ASME

Committee on Operation and Maintenance is preparing a standard,

ANSI/ASME O-17 Performance Testing of Nuclear Power Plant Instrument

Air Systems, that will specify inservice performance tests to assure

that the air system meets required specifications. It is expected that

the standard will require periodic tests of the compressor to demonstrate that the compressor has adequate delivery capacity, bearing

vibration levels are within acceptable limits, various temperatures and

pressures are acceptable, and relief valves are properly operable. The

standard is expected to require frequent measurement of dryer outlet

dewpoint, pressure drops across the dryer chamber and filters, and contamination levels following prefilter and following afterfilter, as well

as verification that the dryer is cycling properly.

Failure modes for the compressor include failure to operate, failure to operate as required, andiexternal leaks. Failure to operate, the

most serious of these, is reflected in the absolute failure of the

machine to respond to a signal to initiate or continue delivery of air

to the using system. Failure to operate as required includes both a.)

failure types in which the machine operates but in a degraded state with

reduced or no output, and b.) degradation of components that, if not

corrected, will ultimately lead to loss of function of the unit.

Compressor failure modes, with identity of the responsible component, cause of the failure, and methods for differentiating between failure causes are listed in Table 7.1. Causes of many of the failures are

identifiable only through machine disassembly and inspection; others are
Table 7.1. Methods for Differentiating Between Compressor Failure Causes

Failure Mode Subcomponent Failure Causes Methods for Differentiation

Failure to operate Drive belt

Running gear

Pressure

switch

Cylinder

Time-delay

relays

Broken or thrown drive belts

Broken coupling

Broken crankshaft

Broken connecting rod

Piston rod disconnected from crosshead

Pressure switch inoperable

Hydraulic lock due to leakage while idle

Piston-head interference

Failure to override low oil pressure

switch or to unload compressor during

startup

Worn or damaged main or crankpin

bearings

Lubricating oil contamination

Pressure switch inoperable or out

of calibration

Unloader, regulator, or control

valve stuck or inoperable

Visual inspection

Visual inspection

Disassembly and inspection

Disassembly and inspection

Disassembly and inspection

Removal and inspection

Disassembly and inspection

Disassembly and inspection

Inspection for operability

and calibration

Auditory, vibration, disassembly and inspection

Visual, sample analysis

Removal and inspection

Disassembly and inspection

Failure to operate

as required

Bearings

Lubricating

oil

Pressure

switch

Unloader
Table 7.1 (continued)

Failure Mode

External leaks

Subcomponent

Packing

Rings

Valves:

Cylinder

Oil wiper

Head gasket

Water jacket

Water valve

Intercooler

Main oil

seals

Caskets and

*fasteners

Failure Causes

Rod packing blowthrough

Broken or excessively worn

rider or compression rings

Leaking, broken, or loose valves

Scored or worn cylinder wall

Oil migration through oil wiper

Blown head gasket

Fouled water passages

Failure to open completely

-Failure to close

Fouled heat exchange surface

or restricted water passages

Automatic drain malfunction

Oil leaks at main seals

Oil, water, or air leaks at

gasketed joints

.

Methods for

Differentiation

Auditory, visual inspection

Disassembly and inspection

Auditory, disassembly and

inspection

Disassembly and inspection

Visual inspection

Auditory, visual inspection

Disassembly and inspection

Operational inspection

Operational inspection

Disassembly and inspection

Operational inspection

Visual inspection

Visual inspection -
44

obvious either through auditory and visual inspection while the machine

is operating or visual inspection subsequent to the failure to operate.

Dryer failure modes, identity of the responsible component, cause

of the failure, and methods for differentiating between causes are

listed in Table 7.2. Many of the failure causes are identifiable by an

operational inspection, with subsequent disassembly and inspection

required in some cases.

7.2 Measurable Parameters for Establishing

Degradation Trends

In the preceding subsection, failure mode determination and failure

cause differentiation were considered. Measurable parameter use was

also included in those considerations. As stated in the NPAR1 strategy,

a prime objective of this Phase I assessment is to enlarge on that use

by introducing measurable parameters that have potential for being combined with those already identified to enhance capabilities for incipient failure detection and examination of degradation trends.

7.2.1 Compressors

Compressor failures to operate, as listed in Table 7.1, generally

do not have measurable parameters that would indicate precursors to

failure. These events usually are associated with sudden, catastrophic

failure of a critical part in the machine that can be readily identified

on inspection following failure, but which could be foretold only

through periodic disassembly and nondestructive tests of the vulnerable

component. In view of the infrequent nature of these failures and the

redundancy provided, this type of inspection is not justified.

Failures to operate as required, listed in Table 7.1, often represent gradual time-dependent degradation of a component that is detectable by monitoring and trending of various measurable parameters. Measurable parameters associated with each of the failure causes are given

in Table 7.3. Many of these are presently used in compressor diagnostics; others are not widely used but appear to offer potential for indicating degradation.

Periodic measurement of compressor capacity, at specified discharge

pressure, can provide an overall assessment of compressor condition.

Compressor duty cycle, determined from loaded and unloaded operating

hours, provides an indication of capacity but is also affected by air

usage rate and the leak tightness of the entire air system and its airusing equipment. Time-based trending of capacity and/or duty cycle may

be used to detect degradation and to predict when refurbishment will be

required.

Air temperatures at the suction and discharge of each compressor

stage and stage discharge pressures are excellent indicators of the
Table 7.2. Methods for Differentiating Between Dryer Failure Causes

Failure Mode Subcomponent Failure Causes Methods for

Differentiation

Desiccant Dryer

Failure to operate

as required

Prefilter

Valves

Desiccant

Heater

Blower

Afterfilter

Controls

Damaged filter element

Clogged element

Valves stuck, leaking, or inoperative

Desiccant attrition

Desiccant fouling

Heater inoperative

Blower inoperative

Damaged filter element

Clogged element

Improper operation of cycle timer

Improper temperature control

Air sample, disassembly

and inspection

Pressure drop

Operational inspection,

disassembly and inspection

Operational inspection,

disassembly and inspection

Operational inspection,

disassembly and inspection

Operational inspection

Operational inspection

Air sample, disassembly and inspection

Pressure drop

Operational inspection,

in-bed moisture sensor

Operational inspection

Van
Table 7.2 (continued)

Failure Mode Subcomponent Failure Causes Methods for Differentiation

Refrigerated Dryer

Failure to operate Gas bypass Valve set improperly or inoperative Operational inspection

as required valve

Drain traps Traps leaking or stuck open Auditory, visual inspection

Traps clogged or stuck closed Operational inspection

a'
Table 7.3. Measurable Parameters for Compressors

Subcomponent

Bearings

Lubricating

oil

Pressure

switch

Unloader

Packing

Rings

Valves

Cylinder

Oil wiper

Head gasket

Water jacket

Water valve

Failure Causes

Worn or damaged main or crankpin

bearings

Lubricating oil contaminated

Pressure switch inoperable or out

of calibration

Unloader, regulator, or control

valve stuck or inoperable

Rod packing blowthrough

Broken or excessively worn

rider or compression rings

Leaking, broken, or loose valves

Scored or worn cylinder wall

Oil migration through oil wiper

Blown head gasket

Fouled water passages

Failure to open completely

Failure to close

Methods for Differentiation

Vibratory amplitude, velocityA and spectrum,

dimensions, appearance, MCSA

Visual for presence of water, analysis for

bearing or crosshead wear particles

Bench test - pressure to open, pressure to

close

Loaded/unloaded hours, appearance, cleanliness, bench test

Loaded/unloaded hours, noise, rod appearance,

capacity, MCSA

Loaded/unloaded hours, dimensions, appearance,

capacity, air temperatures and pressures,

MCSA

Loaded/unloaded hours, noise, air temperatures

and pressures, appearance, capacity, MCSA

Loaded/unloaded hours, dimensions, appearance,

capacity, MCSA

Rod appearance, oil consumption rate

Loaded/unloaded hours, noise, appearance,

capacity, MCSA

Air and water temperatures

Air and water temperatures, water flow rate

Water temperatures, water flow rate
Table 7.3 (continued)

Subcc

Inter

omponent Failure Causes

-cooler Fouled heat exchange surface

or restricted water passages

Automatic drain malfunction

aMotor current signature analysis.

Methods for Differentiation

Air and water temperatures, water flow rate

Condensate volume during manual blowdown

J.-
49

condition of valves, compression rings, and intercooler, and can often

provide an early warning of component degradation.12 Table 7.4, adapted

from Ref. 12, shows the effects of faulty valves and rings on stage temperatures and pressures. Trending of these parameters as a function of

time may provide guidance in the determination of need and scheduling

for maintenance.

Table 7.4. Effects of Faulty Components on Stage

Temperatures and Pressures

Temperatures

- Pressures

Stage 1 Stage 2

Faulty Stage Stage

Component 1 2 Suction Discharge Suction Discharge

Valves

Stage 1 suction LOW low HIGH low low high

Stage 1 discharge LOW low - HIGH high high

Stage 2 suction HIGH LOW - HIGH high low

Stage 2 discharge high LOW - high high low

Compression rings

Stage 1 LOW low - HIGH high low

Stage 2 high LOW - high high HIGH

Tabulation indicates pressures or temperatures higher or lower than

normal. -

Capitals indicate location of most pronounced effect.

Analysis of lubricating oil samples for composition and size distribution of particulates can indicate wear of the running gear bearings

and crosshead. Increasing concentrations of bearing material and

increasing wear particle size are indications of distressed wear surfaces. Ref. 2recommends trending of these parameters against operating

time.

Motor current signature analysis is a recently developed technique

for detecting changes in the operating condition of electrically driven

mechanisms.1 The driving motor serves as the transducer to provide a

current trace that, when examined both spectrally and in the time

domain, can reflect small disturbances in motor torque indicative of

mechanical degradation of mechanism components. If this technique can

be adapted to reciprocating compressor application, it is conceivable
50

that the equivalent of a pressure-volume indicator card for an operating

compressor could be derived from the motor current. The indicator card

is a traditional and highly valuable tool for diagnostics of this type

machinery.

7.2.2 Dryers

Failures to operate as required, listed in Table 7.2, are usually

detected either by system walkdowns, by inspections during operation, or

by indicated elevated exit air dewpoint. Measurable parameters that can

be used to identify any specific problem are presented in Table 7.5.

These include the presently used parameters: pressure drops across the

filters and the dryer chambers; process temperatures during the different phases of the operating cycle; and the dewpoint of the air

leaving the dryer. Of these, only dewpoint appears to offer the opportunity for meaningful trending (to identify faulty regeneration cycle or

degradation of the desiccant with time and use).

Use of a moisture-sensing probe, located within the desiccant bed

near the dry-air exit end, could provide an indication of the adequacy

of the active/regeneration cycle and the moisture retention capability

of the desiccant charge. (Such a probe is used to control the active/

regeneration cycle in the Pall Model DEA dryer.)

Another approach to monitoring for impending bed saturation and

moisture breakthrough, as well as desiccant degradation, would be based

on measuring the bed axial temperature profile (which indicates the

position in the bed and the length of the active adsorption zone) during

operation. As the drying process proceeds in the active column, the

adsorption zone progresses from the inlet end toward the exit end, and

the exothermic adsorption process causes an elevated temperature front

to progress through the bed. Degradation of the adsorption capability

of the desiccant, due to contamination or other aging deterioration,

would be expected to result in an increase in the length of the adsorption zone. Periodic measurement of the temperature profile, by means of

a series of temperature sensors in the bed, should provide an indication

of the location of the saturation front and guidance on the need for

cycle adjustment or desiccant replacement.
Tabl e 7 . Measurable Parameters for Dryers

Subcomponent Failure Causes Measurable Differentiation

Desiccant Dryer

Prefilter Damaged filter element Filter pressure drop

Clogged element Filter pressure drop

Valves Valves stuck, leaking, or inoperative Noise, pressures, temperatures

Desiccant Desiccant attrition Dryer pressure drop, exit dewpoint,

afterfilter performance, appearance

Desiccant fouling Exit dewpoint, in-bed moisture, bed axial

temperature profile, appearance

Heater Heater inoperative Exit dewpoint, temperatures

Blower Blower inoperative Exit dewpoint, blower current, noise

Afterfilter Damaged filter element Filter-pressure drop, air sample particulates, appearance

Clogged element Filter pressure drop, appearance

Controls Improper operation of cycle timer Exit dewpoint, temperatures, pressures

Improper temperature control Exit dewpoint, temperatures
52

8. SUMMARY AND RECOMMENDATIONS

The objective of this study was to identify failure modes and

causes resulting from aging of control and service air compressors and

dryers in nuclear plant service and to identify measurable parameters

that are suitable for detecting and establishing time-dependent degradation trends prior to failure, as well as providing guidance for effective maintenance. To this end, operating experience information,

nuclear industry reports, manufacturer-supplied information, and results

from discussions with plant operators have been used.

Failure modes are of two types: complete failure to operate, and

operation in a degraded condition that results in reduced capability or

that, if uncorrected, will ultimately lead to complete failure to operate. Cause of complete failure to operate often is failure of a critical component or appurtenance of a compressor, an event for which there

is little warning. Review of operating experience data revealed no

dominant type of failure. No measurable parameters were identified to

portend this type of failure.

Certain parts of a reciprocating compressor, principally rings,

valves, and rod packing, undergo wear during service and are routinely

replaced or refurbished when performance deteriorates or wear limits are

reached. Operating experience data does not show any appreciable

increase in required maintenance with increasing age. The degraded condition is often detected by either system walkdowns or periodic partial

disassembly and inspection. Early detection and tracking of compressor

degradation can be enhanced by the use of identified measurable parameters, including stage temperatures and pressures, compressor duty

cycle, delivery capacity, and motor current signature analysis.

Dryer components that require periodic maintenance or replacement

to provide dependable service include regeneration cycle controls,

operating valves, the desiccant, and filter elements. Degradation of

these components is presently detected by operational surveillance and

performance (exit dewpoint). Identified measurable parameters that

would enhance detection or tracking of dryer degradation include

humidity measured within the desiccant bed a short distance from the

dry-air exit end by means of a permanently installed probe, and measurement of the axial temperature profile within the bed by means of a

series of temperature sensors.

Instances where loss of the air supply occurs due to compressor or

dryer failure are rare, because equipment failures to operate are rare

and redundancy is provided in most systems to preclude loss of system

air supply from failure of a single machine. An effective surveillance

and monitoring program, with preventative and corrective maintenance,

can provide reliable service from the compressors and dryers. For these

reasons, it is recommended that this equipment be deleted from further

aging consideration in the NPAR program.
53

REFERENCES

1. Nuclear Plant Aging Research (NPAR) Program Plan, Components, Systems and Structures, NUREG-1144, Rev. 1, September 1987.

2. E. W. Hagen, Compressed-Air and Backup Nitrogen Systems in Nuclear

Power Plants, NUREC/CR-2796 (ORNL/NSIC-206), July 1982.

3. H. L. Ornstein, Operating Experience Feedback Report - Air Systems

Problems, Commercial Power Reactors, NUREG-1275, Vol. 2, December

1987.

4. NRC memorandum from E. S. Beckjord to B. W. Sheron, subject:

"Generic Issue No. 43, Reliability of Air Systems," April 11, 1988.

5. M. Villaran, R. Fullwood, and M. Subudhi, Aging Assessment of

Instrument Air Systems in Nuclear Power Plants, NUREC/CR-5419

(BNL-NUREG-52212), January 1990.

6. K. R. Hoopingarner, J. W. Vause, D. A. Dingee, and J. F. Nesbitt,

Aging of Nuclear Station Diesel Generators: Evaluation of Operating

and Expert Experience, Phase I Study, NUREG/CR-4590 (PNL-5832),

Vol. 1, August 1987.

7. Maintenance Instructions, Model PHE Horizontal Balanced-Opposed

Stationary Air Compressors, Form AP-0150-B, Ingersoll-Rand Company,

March 1975

8. M. Subudhi, E. L. Burns, and J. H. Taylor, Operating Experience and

Aging-Seismic Assessments of Electric Motors, NUREG/CR-4156 (BNLNUREG-51861), June 1985.

9. V. P. Bacanskas, C. C. Roberts, and C. J. Toman, Aging and Service

Wear of Solenoid-Operated Valves Used in Safety Systems of Nuclear

Power Plants: Operating Experience and Failure Identification,

NUREG/CR-4819 ORNL/Sub/83-28915/4/VI), Vol. 1, March 1987.

10. W. M. Stanton, Selection and Application of Industrial Air Compressors, Proceedings of the American Power Conference, Chicago, 1965,

pp. 677-684.

11. Installation, Operating and Maintenance Instructions for Regenerative Compressed Air Dryer, Air Components and Systems, Ltd.,

Knoxville, TN.

12. System Performance and Condition Evaluation (PCE) Book for F 1052

Class High Pressure Compressed Air System, prepared by Westinghouse

Electric Corporation for the U.S. Navy System and Equipment Maintenance Monitoring for Surface Ships (SEMMSS) Program, Naval Sea

Systems Command, Washington, May 1987.
54

13. H. D. Haynes, Aging and Service Wear of lectric Motor-Operated

Valves Used in Engineered Safety-Feature Systems of Nuclear Power

Plants: Aging Assessments and Monitor Method Evaluations,

NUREG/CR-4234 (ORNL-6170/V2), Vol. 2, August 1989.
55

APPENDIX A

AIR COMPRESSORS AND DRYERS IN U.S. NUCLEAR PLANTS

AS DESCRIBED IN SAFETY ANALYSIS REPORTS
57

N/S

NO.

CFM

NOMENCLATURE

- Information not specified in reference document

- Number of compressors or dryers used. Where compressors

or dryers are shared by more than one reactor, number is

given as a fraction (e.g., 4/2 denotes four units shared

by two reactors).

- Capacity of unit, ft3 /min

TYPE - Type of compressor or dryer

Compressor:

CENTR - Centrifugal

DIAPH - Diaphragm

LS ROT - Liquid seal rotary

RECIP - Reciprocating

SCREW - Rotary screw

(SRVC) - Instrument air provided by service air compressor

Dryer:

HTLESS - Heatless regenerative desiccant

HT REC - Heat regenerative desiccant

REGEN - regemerative desiccant (not specified whether heatless or

'heat regenerative)

REFRIG - Refrigerated

COMBO - Combination refrigerated and desiccant

LUB - Type of air-side lubrication

N - Nonlubricated

Oil - Oil lubricated

APPLIC.

AUX

ADS

BACKUP

CNTMNT

DRYWELL

EMERGY

ESF

IAN

MAIN

NONINTR

NSSS

NUCLEAR

SHUTDWN

DESIC

ALUMA

S GEL

- Instrument air compressor application

- Auxiliary instrument air

- Automatic Depressurization System air

- Backup instrument air

- Containment instrument air

- Drywell instrument air

- Emergency instrument air

- Engineered Safety Feature air

- Noninterruptible instrument air

- Provides main instrument air

- Noninterruptible instrument air

- Nuclear Steam Supply System instrument air

- Same as NSSS

- Shutdown instrument air

- Desiccant type

- Activated alumina

- Silica gel
58

AIR COMPRESSORS AND DRYERS IN U.S. NUCLEAR PLANTS

AS DESCRIBED IN SAFETY ANALYSIS REPORTS

UNIT

Beaver Valley I

Beaver Valley 2

Bellefonte 1

Bellefonte 2

Big Rock Point

Braidwood 1

Braldwood 2

Browns Ferry I

Browns Ferry 2

Browns Ferry 3

BrunswIck I

Brunswick 2

Byron 1

Byron 2

Callaway 1

Calvert Cliffs I

Calvert Cliffs 2

COMPRESSORS

SERVICE AIR INSTRUMENT AIR

NO. CFM TYPE LUB NO. APPLIC. CFM TYPE LUB

3 350 RECIP NL 0 MAIN (SRVC)

2 CONTNMT 50 RECIP NL

2 728 SCREW NL 0 MAIN (SRVC)

2 CONTNMT 30 N/S NL

4/2 720 RECIP NL 0 MAIN (SRVC)

4/2 720 RECIP NL 0 MAIN (SRVC)

3 70 N/S NL 0 MAIN (SRVC)

3/2 2190 CENTR N/S 0 MAIN (SRVC)

3/2 2190 CENTR N/S 0 MAIN (SRVC)

1/3 950 N/S N/S 4/3 MAIN 610 N/S N/S

1/3 590 N/S N/S 2 DRYWELL 9 N/S NL

1/3 950 N/S N/S 4/3 MAIN 610 N/S N/S

1/3 590 N/S N/S 2 DRYWELL 9 N/S NL

1/3 950 N/S N/S 4/3 MAIN 610 N/S N/S

1/3 590 N/S N/S 2 DRYWELL 9 N/S NL

3 334 RECIP NL 0 MAIN (SRVC)

2 IAN 19.5 N/S N/S

3 334 RECIP NL 0 MAIN (SRVC)

2 IAN 19.5 N/S N/S

3/2 2190 CENTR N/S 0 MAIN (SRVC)

3/2 2190 CENTR N/S 0 MAIN (SRVC)

3 525 RECIP NL 0 MAIN (SRVC)

1 616 RECIP N/S 2 MAIN 470 RECIP NL

1 616 RECIP N/S 2 MAIN 470 RECIP NL

DRYERS

NO. TYPE DESIC.

I HT REG N/S

I HT REG

2 REFRIG

1/2 REGEN

1/2 REGEN

I REGEN

3/2 REGEN

3/2 REGEN

4/3 REGEN

2 REFRIG

4/3 REGEN

2 REFRIG

4/3 REGEN

2 REFRIG

I HT REG

N/S

N/S

NS

N/S

ALUMA

ALUMA

N/S

N/S

N/S

N/S

1 HT REG N/S

3/2 REGEN ALUMA

3/2 REGEN ALU9IA

2 HTLESS NS

I HTLESS ALUMA

I HTLESS ALUMA
59

UNIT

Catawba I

Catawba 2

Clinton 1

Comanche Peak I

Comanche Peak 2

Cooper

Crystal River 3

Davis-esse 1

Diablo Canyon I

Diablo Canyon 2

Donald Cook I

Donald Cook 2

Dresden 2

Dresden 3

Duane Arnold

Edwin 1. Hatch I

Edwin 1. Hatch 2

Fermi 2

Fort Calhoun I

SERVICE AIR

NO. CFM TYPE U

2/2 750 SCREW 01

2/2 750 SCREW 01

3 2000 NIS N

2/2 1500 CENTR N

2/2 1500 CENTR N)

3 775 RECIP A

2 335 N/S N)

1 766 N/S N

1 992 N/S 1N

2/2 650 SCREW N

4/2 334 RECIP N

2/2 650 SCREW IN

4/2 334 RECIP N

COMPRESSORS

INSTRUMENT AIR

JO NO. APPLIC. CFM TYPE LUB

IL 3/2 MAIN 650 RECIP NL

IL 3/2 MAIN 650 RECIP NL

/S 0 MAIN (SRVC)

fS 3/2 MAIN 350 RECIP NL

/S 3/2 MAIN 350 RECIP NL

IL 0 MAIN (SRVC)

/S 2 MAIN 345 RECIP NL

IL 0 MAIN (SRVC)

IL 1 EMEROCY 160 N/S NL

IL 0 MAIN (SRVC)

DRYERS

NO. TYPE ESIC.

4/2 REFRIG

4/2 REFRI

3 HTLESS ALUMA

2/2 HT REG ALUMA

2/2 HT REG ALUMA

2 HT REG N/S

I N/S N/S

I HTLESS ALUA

2/2 HT REG N/S

2/2 HT REG N/S

2 REGEN N/S

2 REGEN N/S

I N/S N/S

I N/S NJS

IL

IL

IL

0 MAIN (SRYC)

1 1500 CENTR NL 0 MAIN

I BACKUP

I 1500 CENTR ML 0 MAIN

I BACKUP

1 600 N/S N/S I MAIN

I MAIN

1 600 N/S N/S I MAIN

2 MAIN

3 N/S RECIP NL 0 MAIN

3 578 RECIP NL 0 MAIN

2 DRYWELL

3 527 RECIP NL 0 MAIN

2 DRYWELL

3 1225 RECIP NL 0 MAIN

2 NONINTR

3 710 RECIP NL 0 MAIN

(SRVC)

317 RECIP

(SRVC)

317 RECIP

200 RECIP

400 RECIP

200 RECIP

400 RECIP

(SRVC)

(SRVC)

5 NS

(SRVC)

5 N/S

(SRVC)

100 RECIP

(SRVC)

NL

NL

N/S

N/S

N/S

N/S

I HT REG

2 REGEN

NL I N/S

2 REGEN

NL I REFRIG

3 N/S

NL

N/S

NIS

N/S

N/S

N/S

I REGEN N/S
60

cOO SERVICE AIR

UNIT

Fort St. Vrain

Grand Gulf I

Grand Gulf 2

Haddam Neck

Hope Creek I

Indian Point 2

Indian Point 3

James FitzPatrick

Joseph M. Farley 1

Joseph M. Farley 2

Kewaunee

LaSalle County 

LaSalle County 2

Limerick 1

Limerick 2

Maine Yankee

McGuire 1

SERVICE AIR

NO. CFM TYPE LL

1 N/S N/S OIL

2/2 N/S CENTR NS

2/2 N/S CENTR NS

1 687 N/S NS

2 3000 CENTR NL

1 625 N/S N/S

N/S N/S N/S NS

3 500 RECIP NL

5 550 RECIP NS

4 550 RECIP NS

N/S N/S N/S N/S

3/2 1750 CENTR NL

3/2 1750 CENTR NL

2 397 RECIP NS

1 397 RECIP N/S

3 317 RECIP NL

2/2 750 SCREW OIL

4PRESSORS

INSTRUMENT AIR

NO. APPLIC. CFM TYPE LUS

3 MAIN N/S N/S NL

1 MAIN N/S CENTR NS

2 ADS N/S RECIP NL

1 MAIN N/S CENTR NS

2 ADS N/S RECIP NL

2 MAIN 16B RECIP NL

2 CNTIT N/S N/S NS

0 MAIN (SRVC)

1 EMERGY 500 RECIP NL

2 CNTMNT 35 RECIP NI

2 MAIN 225 RECIP NI

DRYERS

NO. TYPE DESIC.

2 N/S NS

I HTLESS N/S

1 HTLESS N/S

2 REGEN S GEL

2 HTLESS N/S

2 HTLESS N/S

2 REFRIG

N/S N/S

O MAIN

O MAIN

0 MAIN

N/S NS

0 MAIN

2 DRYWELL

O MAIN

2 DRYWELL

2 MAIN

2 CNTHNT

2 MAIN

2 CNTMNT

O MAIN

2 CNTMNT

3/2 MAIN

N/S NS

(SRVC)

(SRVC)

(SRVC)

N/S N/S

(SRVC)

N/S RECIP

(SRVC)

N/S RECIP

397 RECIP

10 RECIP

397 RECIP

10 RECIP

(SRVC)

26 NS

650 RECIP

I REGEN

N/S N/S N/S

3 HT REG

2 REGEN

2 REGEN

N/S N/S N/S

4 REGEN

NI

NVS

N/S

N/S

N/S

N/S

N/S

N/S

1 REGEN N/S

NL

N/S 2 REGEN N/S

NL 2 REFRIG

N/S 2 REGEN N/S

NL 2 REFRIG

2 HT REG ALUJMA

N/S 2 N/S N/S

NL 4/2 REFRIG

1/2 REGEN N/S

NL 4/2 REFRIG

1/2 REGEN N/S

McGuire 2 212 750 SCREW OIL 3/2 MAIN 650 RECIP
61

COMPRESSORS

SERVICE AIR

NO. CFM TYPE LUB

INSTRUMENT AIR DRYERS

UNIT NO. APPLIC. CFM TYPE LUB NO. TYPE DESIC.

Millstone 1

Millstone 2

Millstone 3

Monticel lo

Nine Mile Point 1

Nine Nile Point 2

North Anna I

North Anna 2

Nuclear One 1

Nuclear One 2

Oconee I

Oconee 2

Oconee 3

Oyster Creek I

Palisades

Palo Verde I

Palo Verde 2

Palo Verde 3

Peach Bottom 2

Peach Sottom 3

1 653 RECIP NL

1 323 RECIP NL

1 750 N/S NL

1 MAIN

2 MAIN

2 MAIN

2 SHUTOWN

0 MAIN

653

323

750

150

RECIP

RECIP

N/S

N/S

(SRVC)

NL

NL

NL

N/S

I REGEN

I REGEN

3 REGEN

N/S

ALUMA

N/S

1 376

2 290

N/S NL

N/S NL

I HT REG N/S

1 500 RECIP NL I MAIN

2 MAIN

3 N/S N/S N/S 0 MAIN

I ADS

1 373 N/S NL I MAIN

2 CNTMNT

1 373 N/S ML I MAIN

4 CNTMNT

2 100 N/S OIL 3 MAIN

I 100 N/S OIL 2 MAIN

N/S N/S N/S N/S N/S N/S

N/S N/S N/S N/S N/S N/S

N/S N/S N/S N/S N/S N/S

3 771 RECIP NL 0 MAIN

3 200 RECIP NL 0 MAIN

3 ESF

3 500 N/S N/S 0 MAIN

3 500 N/S N/S 0 MAIN

3 500 N/S N/S 0 MAIN

4 377 RECIP NL 0 MAIN

2 DRYWELL

3 377 RECIP NL 0 MAIN

2 DRYWELL

729 RECIP

485 RECIP

(SRVC)

N/S N/S

373 N/S

25 N/S

373 N/S

25 N/S

200 N/S

528 N/S

N/S N/S

N/S N/S

N/S N/S

(SRVC)

(SRVC)

22 N/S

(SRVC)

(SRVC)

(SRVC)

(SRVC)

N/S N/S

(SRVC)

N/S N/S

NL

NL

2 REGEN N/S

2 REFRIG

N/S 1 REGEN N/S

NL 1 REFRIG

N/S 2 REGEN N/S

NL 2 REFRIG

N/S 2 REGEN N/S

NL 2 REGEN N/S

NL 1 REGEN N/S

N/S N/S N/S N/S

N/S N/S N/S N/S

N/S N/S N/S N/S

2 HT REG N/S

I HT REG S GEL

OIL 3 REFRIG

I REGEN N/S

I REGEN N/S

I REGEN N/S

2 HTLESS ALUMA

N/S 2 N/S N/S

2 HTLESS ALU4A

N/S 2 N/S N/S
62

UNIT

Perry 1

Perry 2

Pilgrim 1

Point Beach 1

Point Beach 2

Prairie Island I

Prairie Island 2

Quad-Cities 1

Quad-Cities 2

Rancho Sco

River Bend 1

Robert Gnna

Robinson 2

COMPRESSORS

SERVICE AIR INSTRUMENT AIR NO. CF9 TYPE LUB NO. APPLIC. CFM TYPE

1 N/S N/S N/S 1 MAIN N/S N/S

1 ADS 16 RECIP

1 N/S N/S N/S 1 MAIN N/S N/S

1 ADS 16 RECIP

2 655 SCREW N/S 0 MAIN (SRVC)

3 160 RECIP NL

N/S N/S N/S N/S

NS N/S N/S NS

3/2 405 RECIP NL

3/2 405 RECIP NL

3/2 N/S RECIP OIL

3/2 N/S RECIP OIL

3 N/S N/S NL

3 N/S N/S NL

1 N/S RECIP NS

1 400 RECIP OIL

3/2 4000 CENTR NL

NS NS

N/S N/S

O MAIN

O MAIN

2 MAIN

2 MAIN

O MAIN

0 MAIN

3 MAIN

I MAIN

2 MAIN

0 MAIN

1 ENERGY

0 MAIN

1 EUERGY

0 MAIN

1 EUERGY

0 MAIN

0 MAIN

0 MAIN

2 CNTMNT

0 MAIN

2/2 AUX

N/S NS

NS NS

(SRVC)

(SRVC)

N/S LS ROT

NS LS ROT

(SRVC)

(SRVC)

N/S RECIP

516 RECIP

200 RECIP

(SRVC)

500 RECIP

(SRVC)

500 RECIP

(SRVC)

98 RECIP

(SRVC)

(SRVC)

(SRVC)

N/S N/S

(SRVC)

78 RECIP

DRYERS

LU8 NO. TYPE DESIC.

N/S 2 COB0 N/S

NS

N/S 2 COMBO NS

NS

2 HTLESS N/S

N/S N/S N/S N/S

N/S s NS N/S

2/2 REGEN NS

2/2 REGEN N/S

N/S 2 HTLESS ALLIUA

N/S 2 HTLESS ALLMA

I HT REG NS

2 HT REG NS

NL 2 HTLESS NS

ML 1 REFRIG

NL 2 REGEN NS

2 HTLESS N/S

NL

1 HTLESS NS

NI

1 HT REG N/S

NS

2/2 REFRIG

2/2 REFRIG

2 COMO N/S

NS 2 N/S NS

5/2 REGEN N/S

NL

Sale I

Sale 2 3/2 4000 CENTR NL

San Onofre 1

San Onofr 2

San Onofre 3

Seabrook I

Sequoyah I

3 300 RECIP NS

3/2 800 RECIP NL

3/2 800 RECIP NL

3 N/S RECIP NL

4/2 610 RECIP NL
63

COMPRESSORS

SERVICE AIR INSTRUMENT AIR DRYERS

LUNIT NO. CFM TYPE LG NO-. APPLIC. CFM TYPE LUW NO. TYPE DESIC.

Sequoyah 2

Shearon Harris

Shoreham

South Texas Project 1

South Texas Project 2

St. Lucle I

St. Lucie 2

Surry I

Surry 2

Susquehanna 1

Susquehanna 2

Three Mi. Island I

Trojan

Turkey Point 3

Turkey Point 4

Vermont Yankee

Virgil C. Summer I

4/2 610 RECIP NL 0 NAIN

2/2 AUX

2. 527 RECIP NL 0 MAIN

3 NS CENTR NL 0 MAIN

2 N/S RECIP NL 2 MAIN

2 N/S RECIP NL 2 MAIN

I 51t RECIP N/S 2 MAIN

1 665 SCREW NS 2 CNTMNT

I 518 RECIP N/S 2 MAIN

2 373 RECIP NL I MAIN

2 CNTMNT

1 373 RECIP NL I MAIN

2 CNTMNT

2 440 N/S N/S 2 MAIN

2 CNTNNT

2 440 N/S N/S 2 MAIN

2 CNTWNT

2 N/S NS OIL 2 MAIN

2 BACKUP

1 650 SCREW N/S 0 MAIN

(SRVC)

78 RECIP

(SRVC)

(SRVC)

N/S RECIP

N/S RECIP

162 RECIP

48 LS ROT

231 RECIP

373 RECIP

24 LS ROT

373 RECIP

24 LS ROT

440 N/S

40 N/S

440 NJS

40 NS

NIS NS

N/S N/S

(SRVC)

NL

NL

NL

NL

NL

NL

NL

N/S

NL

N/S

WS

N/S

N/S

N/S

NL

NS

5/2 REGEN N/S

2 HT REG N/S

I HT REG N/S

2 HTLESS N/S

2 HTLESS NS

I 00 ALUNA

2 HTLESS ALUMA

I HT REG ALUMA

I REFRIG

I REGEN N/S

I REFRIG

1 REGEN N/S

2 HT REG NS

2 REGEN N/S

2 T REG N/S

2 REGEN N/S

1 N/S N/S

I HT REG NS

3 337 RECIP NL

I

I

N/S N/S N/S N/S N/S N/S

N/S N/S N/S N/S N/S N/S

4 323 'NS NL 0 MAIN

2 CNTMNT

2 1298 CENTR N/S 0 MAIN

2 NSSS

2 750 SCREW N/S 0 MAIN

2 885 RECIP NS

NIS N/S

N/S N/S

(SRVC)

N/S N/S

(SRVC)

150 RECIP

(SRVC)

N/S N/S N/S

N/S N/S N/S

3 HT REG

NL

I HT REG

NL 2 REFRIG

3 REGEN

N/S

N/S

N/S

ALUMA

Vogtle 1 NS
64

UNIT

Vogtie 2

Waterford 3

Watts Bar 1

COWRESSORS

SERVICE AIR INSTRUMENT AIR

NO. CFM TYPE LU8 NO. APPLIC. CFlt TYPE

2 750 SCREW N/S 0 MAIN (SRVC)

1 885 RECIP N/S

3 280 LS ROT NL 2 MAIN 280 LS ROT

4/2 610 RECIP NL 0 MAIN ISRVC)

Watts Bar 2

WNP-I

4/2 610 RECIP NL

2 515 RECIP NL

3 450 N/S N/S

I N/S RECIP NL

3 525 RECIP NL

1 514 RECIP OIL

3/2 N/S N/S N/S

3/2 N/S N/S N/S

2/2 AUX

0 MAIN

2/2 AUX

0 MAIN

2 NUCLEAR

0 MAIN

2 CNTMNT

2 MAIN

0 MAIN

2 MAIN

3/2 MAIN

3/2 MAIN

78 RECIP

(SRVC)

78 RECIP

(SRVC)

N/S DIAPH

(SRVC)

50 N/S

581 RECIP

(SRVC)

125 RECIP

N/S RECIP

N/S RECIP

DRYERS

LU85 NO. TYPE DESIC.

3 REGEN N/S

NL 2 HTLESS ALUMA

3/2 HTLESS N/S

NL 2/2 REGEN N/S

3/2 HTLESS N/S

NL 2/2 REGEN N/S

2 HTLESS N/S

N/S 2 HTLESS ALUNA

2 REGEN ALUMA

N/S

NL I REGEN N/S

2 HTLESS N/S

NL 2 HT REG S GEL

N/S 3/2 N/S N/S

N/S 3/2 N/S N/S

WNP-3

Wolf Creek

Yankee

Zion 1

Zion 2
65

APPENDIX B

COMPRESSOR AND DRYER PROBLEMS FROM

LER AND NPE SEARCHES

Table B.1 Compressor Problems from LER and NPE Searches

(by Problem Type) .................................. 67

Table B.2 Dryer Problems from LER and NPE Searches

(by Problem Type) ................................... 71
67

Table .1

COMPRESSOR PROBLEMS FROM LER AND NPE SEARCHES

(BY FAILURE TYPE)

PLANT NAME DATE LER REMARKS SOURCE

FAILiiRE TYPE: Belts

BEAVER VALLEY 1

BEAVER VALLEY 1

MILLSTONE POINT I

02/11/78 Containment IAS compressor tripped when

2 belts broke and other 3 Jammed.

Backup Inoperable; cross-tie to outside

IAS temporarily made but reactor was

tripped when compressor restart failed.

NPE-P9H148

CR-2796

CR-2796

/ n8 014 One containment IA compressor tripped;

backup broke two belts and other three

belts Jammed on startup.

/ n7 024 Backup IAS compressor threw Its belts on

startup.

FAILURE TYPE: Controls

BRUNSWICK 1

MONTICELLO

YANKEE ROWE

02/24/80 012 Two of three service air compressors

failed, due to bad air pressure switch.

09/11/71

10/04/86

Failed primary compressor control and

standby compressor being In Inadvertent

"off" position resulted In scram. No

compressor problem.

012 Operating IAS compressor pressure switch

failed so compressor would not load.

First backup compressor would not load

due to unloader solenoid valve failure.

Reactor scrammed when second backup

could not restore pressure quickly.

SCSS-NOAC

NPE-B16C47

SCSS-NOAC

SCSS-NOAC

SCSS-NOAC

ZION 1 08/30/85 030 IAS compressor tripped on spurious high

vibration signal; other on-line

compressor could not maintain pressure.

Penetr. pressurization compressors

started ESF.)

ZION 1 11/22/85 043 IA compressor tripped on spurious high

oil temperature (switch out of

tolerance.) Backup compressor still

down for maintenance.
68

Table B.1 (cont'd)

COMPRESSOR PROBLEMS FROM LER AND NPE SEARCHES

(BY FAILURE TYPE)

PLANT NAME DATE LER REMARKS SOURCE

FAILURE TYPE: Heat Exchanger

CALVERT CLIFFS 1

CALVERT CLIFFS 1

ZION 1

05/20/80 027 Instrument air compressor aftercooler

tube failure injected air into service

water system, causing air binding and

reactor trip.

08/12/80 041 IAS compressor aftercooler tube failure.

Air leakage Into service water system.

11/22/85 045 IA compressor trip due to high

intercooler condensate level (trap

bypass valve needed adjustment.)

Penetr. pressurization compressor

started (ESF).

SCSS-NOAC

SCSS-NOAC

SCSS-NOAC

FAILURE TYPE: Leaks

GRAND GULF 1 02/13/85 008 System air compressor believed leaking

air to cooling water. During venting,

instrument air compressor tripped on low

cooling water. Scram resulted. (Was

SAS compressor leaking??)

SCSS-NOAC

INDIAN POINT 2

MILLSTONE POINT I

/ /79 001 Lo-press. cylinder cover plate corroded

and leaked chromate to environment.

/ /77 024 Station compressor head gasket failed,

injecting air into cooling water system,

causing IAS compressor to trip. Reactor

scram.

CR-2796

CR-2796

FAILURE TYPE: Low Output

BEAVER VALLEY 1 / /76 061 Low compressor capacity - unexplained. CR-2796

LA SALLE 2 08/31/88 010 Drywell compressor experienced reduced SCSS-NOAC

output while other compressor was out of

service. No explanation for cause.
69

Table 8.1 (cont'd)

COMPRESSOR PROBLEMS FROM LER AND NPE SEARCHES

(BY FAILURE TYPE)

PLANT NAME DATE LER REMARKS SOURCE

FAILURE TYPE: Mechanical

SEQUOYAH I 07/09/84 045 Second aux. control compressor removed

from service due to rod knock, after

first compressor suffered broken

crankshaft (something Jommed a piston.)

Knock due to broken lockwasher tab which

allowed piston rod to detach from

crosshead.

SCSS-NOAC

FAILURE TYPE: Motor

MCGUIRE 2 09/06/87 016 Short to ground of IAS compressor motor

lug (aging failure of tape) caused

system upset and reactor trip. After

retape, worn motor bearings caused high

current draw.

SCSS-NOAC

FAILURE TYPE: Operational

LA SALLE 1

MONTICELLO

TURKEY POINT 3

02/13/84 011 Centrifugal compressor surged and would

not reload after units were

cross-connected.

o9/11/71

10/11/79

Failed primary compressor control and

standby compressor being In Inadvertent

"off" position resulted In scram. No

compressor problem.

Water In IAS, due to temporary use of

SAS air, caused an AFW pump turbine

control valve to malfunction, disabling

pump.

SCSS-NOAC

NPE-816C47

NPE-P6E246

ZION 1 2 01/11/81 IAS oil contamination from cross-tie to

SAS caused solenoid valve problems.

Third IAS compressor added to reduce

need for SAS cross-tles.

NPE-P9-i6 12
70

Table B.1 (cont'd)

COMPRESSOR PROBLEMS FROM LER AND PE SEARCHES

(BY FAILURE TYPE)

PLANT NAME DATE LER REMARKS SOURCE

ZION I 11/22/85 045 IA compressor trip due to high

intercooler condensate level (trap

bypass valve needed adjustment.)

Penetr. pressurization compressor

started (ESF).

SCSS-NOAC

ZION 2 05/09/80 Oil in IAS caused containment air sample IEIN 81-38

valve to not close.

FAILURE TYPE: Seals

ST. LUCIE I 04/15/77 023 Containment IAS compressor failed due to

loss of seal water. Backup compressor

started but Its discharge blew back

through failed compressor. Reactor trip

to cold shutdown.

NPE-914 17

ZION 1 11/15/85 042 IA compressor trip on low oil pressure SCSS-NOAC

due to worn oil seals In oil pump.

Backup compressor down for maintenance.

Third compressor couldn't maintain

pressure. Penetr. pressurization

compressor started (ESF actuation.)

FAILURE TYPE: Valves and Unloaders

MILLSTONE POINT 1 06/10/87 Instrument air compressor started upon

trip of active compressor but did not

load, due to sticking unloading valve.

NPE-15A347

YANKEE ROWE 10/04/86 012 Operating IAS compressor pressure switch

failed so compressor would not load.

First backup compressor would not load

due to unloader solenoid valve failure.

Reactor scrammed when second backup

could not restore pressure quickly.

SCSS-NOAC
71

Table .2

DRYER PROBLEMS FROM LER AND NPE SEARCHES

(BY FAILURE TYPE)

PLANT NAME DATE LER REMARKS SOURCE

FAILURE TYPE: Controls

ZION I

FAILURE TYPE: Desiccant

12/19/85 040

/ /76 032

Dryer malfunction (vent to atmosphere

due to sequencing solenoid valve opening

out of sequence) during maintenance

caused low lAS pressure. Penetration

pressurization- compressors started-(ESF

actuation.)

Desiccant carryover caused valve

malfunction.

SCSS4OAC

NUCLEAR ONE 1 NUREG-1275

NUCLEAR ONE 2 / /84 014 Desiccant carryover caused feedwater

flow control malfunction and reactor

trip.

NUREG-1275

MUCLEAR ONE 2

RAN=H0 SECO

10/08/85

07/07/61

022 Desiccant carryover fouled IAS, causing

reactor trip (ESF actuated.)

Desiccant In IAS caused air-operated

globe valve to not close.

SCSS-NOAC

IEIN 81-38

FAILURE TYPE: Filter

SAN ONOFRE 1 01/09/80 003

SHOREHAM 08/31/85 035

Failure of-Instrument air filter allowed

desiccant Into IAS, causing malfunction

of service waer Isolation valve.

Low IAS pressure due to plugged dryer

afterflIter, due to Improper replacement

of desiccant. Emergency shutdown.

SCSS-NOAC

SCSS-NOAC
72

Table B.2 (cont'd)

DRYER PROBLEMS FROM LER AND NPE SEARCHES

(BY FAILURE TYPE)

PLANT NAME DATE LER REMARKS SOURCE

FAILURE TYPE: Operational

BEAVER VALLEY 1 08/29/85 015 Failure of soldered fitting in air

system, maybe due to impact during

repair of faulty dryer heater control.

Resulted in reactor trip and ESF

actuation.

SCSS-NOAC

PALISADES / /78 003 Restricted regenerative purge outlet NUREG-1275

resulted in water in AS. Caused

shutdown cooling water valve to close.

SHEARON HARRIS I 08/04/87 041 Improper valve alignment during

restoring dryer to service caused low

IAS pressure and reactor trip.

SURRY I 11/21/85 022 Refrigerated dryer froze up, lowering

lAS pressure and Initiating ESFs.

Freezeup problem not recognized until

later recurrence.

SCSS-NOAC

SCSS-NOAC

SURRY 1 01/07/86 001 Refrigerated dryer froze up, causing low SCSS-NOAC

IAS pressure. Hot gas bypass valve out

of adjustment. Reactor tripped.

FAILURE TYPE: Valve

DAVIS-BESSE 1

INDIAN POINT 2

LA SALLE 1

12/07/87 015 Failure of solenoid valve in IAS dryer

vented air to atmosphere. Reactor trip

resulted, with ESF actuation.

/ /76 015 Four-way inlet switching valve

malfunctioned.

12/31/82 178 Solenoid valves for drywell system dryer

were stuck open (gummy), resulting in

low lAS pressure.

SCSS-NOAC

CR-2796

SCSS-NOAC
73

Table B.2 (cont'd)

DRYER PROBLEMS FROM LER AND NPE SEARCHES

(BY FAILURE TYPE)

PLANT NAME DATE LER REMARKS SOURCE

FAILURE TYPE: Water in System

CRYSTAL RIVER 3 03/23/83 Water in lAS caused FW valve air

accumulator check valves to leak.

Water in IAS caused air-operated control

valve to fail to stay open, disabling

both RHR trains.

PALISADES / /

NPE-P6E444

IEIN 81-38

TURKEY POINT 3 09/26/80 018 Water entering IAS during dryer SCSS-NOAC

maintenance caused AFW control upset.
75

APPENDIX C

IPRDS SERVICE COMPRESSOR AND DRYER

MAINTENANCE CALLS

Table C.1

Table C.2

IPRDS Service Compressor Maintenance Calls

(by Problem Type) ....... s..0.......*. .............

IPRDS Dryer Maintenance Calls (by Problem Type) ......

77

89
77

Table C.1

IPRDS SERVICE COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE

COMPRESSOR "A"

CONCERN PROBABLE CAUSE ACTION TAKEN

PROBLEM TYPE: Belt

3787 CHECK COMPRESSOR FOR A LOOSE

OR BAD BELT. WHILE RUNNING,

SMELLS LIKE BURNT RUBBER.

4445 BELTS SQUEAKING.

4697 BELTS ARE SQUEAKING.

PROBLEM TYPE: Controls

3165 UNIT DOES NOT STAY LOADED.

4706 TRIPPED ON APPARENT Hi TEMP.

4904 PRESSURE INDICATOR ON C203

BROKE.

4908 SUPPLY BREAKER 1B3312

TRIPS WHEN THE COMPRESSOR IS

TAKEN TO START.

MOTOR SHAFT DRAGGING. HAD

ROUGH SPOT WHEN TURNED BY

HAND.

BELTS WERE LOOSE AND THE

PULLEYS WERE MISALIGNED.

FOUND COMPRESSOR RUNNING,

FOUND TRIP FUNCTION COMING IN

BEFORE ALARM.

OVER PRESSURIZED.

CHANGED BOTH BEARINGS ON

MOTOR. CHANGED BELTS AND

CHANGED SHEAVE - FOUND HEAD

GASKET LEAKING.

REALIGNED PULLEYS AND ADJUSTED

THE BELTS.

HAD OPS SHUT OFF COMPRESSOR

WHILE WE INSTALLED A NEW TEMP

SWITCH.

RECALIBRATED GAUGE.

MEG MOTOR A-B-C TO GROUND \

500 R PH TO PH-GOOD. CHECK

STARTER AND HEATERS OHMED OUT

GOOD.

PROBLEM TYPE: Cooling

3005 AIR COMPRESSORS START

OVERHEATING WHENEVER

MAKE-UP DEMIN IS OPERATING.

Date Is serial day after an arbitrarily selected starting date.
78

Table C.? (cont'd)

IPRDS SERVICE COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE

3478

CONCERN

CHEMICAL CLEANING OF WATER

JACKETS IS NEEDED ON AIR

COMPRESSORS.

PROBABLE CAUSE ACTION TAKEN

4047 WATER JACKET FLOW PATHS NEED

FLUSHED.

PROBLEM TYPE: Leak

3272 LEAK IN FLANGED CONNECTION AT

AFTERCOOLER OF AIR COMPRESSOR.

3299 THIS AFTERCOLER HAS AN AIR

LEAK AT OUTLET END.

3362 WELL WATER PIPING TO AFTER

COOLER ON AIR COMPRESSOR IS

LEAKING.

4024 AFTER COOLER IS LEAKING

WATER AT FLANGE THAT ATTACHES

TO MOISTURE SEPARATOR.

4091 CRANKSHAFT AREA HAS OIL LEAK

ON PLATE GASKET.

4334 PREVENTATIVE MAINTENANCE

INSPECTION.

4445 BELTS SQUEAKING.

4446 HEAD GASKET LEAKS.

4569 CONNECTION ON AIR COMPRESSOR

FOR AIRSENSING LINE IS LEAKING

BY.

MOTOR SHAFT DRAGGING. HAD

ROUGH SPOT WHEN TURNED BY

HAND.

FOUND HEAD GASKET LEAKING WHEN

COMPRESSOR WAS RUNNING.

FOUND COMPRESSION FITTING

LEAKING AND COPPER TUBING

CRACK.

OIL LEAKING FROM BOTTOM JOINT

OF THE CENTER COLUMN.

CHANGED BOTH BEARINGS ON

MOTOR. CHANGED BELTS AND

CHANGED SHEAVE - FOUND HEAD

GASKET LEAKING.

REPLACED HEAD GASKET AND

STARTED COMP. MADE A KNOCKING

NOISE.

INSTALLED A NEW COPPER TUBING

WITH NEW FITTINGS.
79

Table C.1 (ont'd)

IPRDS SERVICE COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE CONCERN

4579 HAS AN AIR LEAK ON A

DISCHARGE VALVE COVER.

PROBABLE CAUSE

LEAKING AROUND VALVE COVER

GASKET?

_ACTION TAKEN

TIGHTENED VALVE COVER BOLTS.

PROBLEM TYPE: Mechanical

2982 OIL PRESSURE IS READING LOW.

3361 COMPRESSOR HAS CHATTERING

NOISE WHEN LOADING.

3756 COMPRESSOR IS MAKING A

KNOCKING NOISE WHEN UNLOADED.

3761 COMPRESSOR IS MAKING INTERMITTANT TAPPING NOISE

(SOUNDS LIKE ROD LOOSENING).

PROBLEM TYPE: Motor

4445 BELTS SQUEAKING.

PROBLEM TYPE: Rings

4425 COMPRESSOR IS MAKING KNOCKING

SOUNDS.

MOTOR SHAFT DRAGGING. HAD

ROUGH SPOT WHEN TURNED BY

HAND.

FOUND RIDER RING BROKE ON

THE PISTON. FOUND BAD INTAKE

VALVE.

CHANGED BOTH BEARINGS ON

MOTOR. CHANGED BELTS AND

CHANGED SHEAVE - FOUND HEAD

GASKET LEAKING.

REPLACE INTAKE VALVES. REMOVED

PISTON & INSTALLED NEW PISTON

RINGS AND RIDER RING. CLEANED

PISTON UP.

PROBLEM TYPE: Seal

4361 OIL LEAK. THE OIL IS RUNNING

To FLOOR ORAIN.

FOUND THE OIL SEAL LEAKING ON

THE MAIN CRANK.

INSTALLED NEW OIL SEALS ON THE

MAIN CRAIK.
80

Table C.I (cont'd)

IPRDS SERVICE COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE CONCERN PROBABLE CAUSE ACTION TAKEN

PROBLEM TYPE: Unloader

3198 LOADING VALVE STICKS

PERIODICALLY AND DOES NOT

ALLOW COMPRESSOR TO LOAD.

3212 ELECTRIC LOADING SOLENOID TO

LOADING VALVE STICKS AND DOES

NOT LET COMPRESSOR LOAD.

3258 SOLENOID VALVE DOES NOT WORK.

4194 AIR COMPRESSOR DOES NOT

UNLOAD PROPERLY.

4424 SOLENOID NOT OPERATING.

WILL NOT LOAD.

UNLOADING SOLENOID AND

ASSOCIATED 3 WAY VALVE WERE

BYPASSED.

REMOVED SOLENOID 3 WAY VALVE

AS A UNIT. DETERMINED SOLENOID

TO BE BAD. REPLACED SOLENOID.

PROBLEM TYPE: Valve

3724 POSSIBLE DISCHARGE VALVE

KNOCKING.

3853 COMPRESSOR WAS MAKING A

TAPPING SOUND COMING FRCM THE

VALVE AREA.

4425 COMPRESSOR IS MAKING KNOCKING

SOUNDS.

4447 CHECK PISTON CLEARXNCE AT TOP

AND BOTTOM OF COMPRESSOR.

4474 AIR COMPRESSOR FAILED.

FOUND RIDER RING BROKE ON

PISTON. FOUND BAD INTAKE

VALVE.

FOUND UPPER EXHAUST VALVE

(SOUTHWEST) TO HAVE SEGMENT OF

VALVE BROKEN.

FOUND A DISCHARGE VALVE HAD

COME LOOSE CAUSING THE COPPER

GASKET TO GO INTO CYLINDER.

REPLACE INTAKE VALVES. REMOVED

PISTON & INSTALLED NEW PISTON

RINGS AND RIDER RING. CLEANED

PISTON UP.

REPLACED ALL VALVES. PISTON

END CLEARANCE TOP: .076, BOT

.051. TEST RAN COMP FOR 15 MIN

IN LAG POSITION.

INSTALLED NEW PISTON.

REBUILT VALVES AND P.T. THE

OUTER CYLINDER. FOUND NO

CRACKS.
81

Table C.1 (cont'd)

IPRDS SERVICE COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE I CONCERN

COMPRESSOR "B"

PROBABLE CAUSE ACTION TAKEN

PROBLEM TYPE: Belt

3793 BELTS NEED TO BE TIGHTENED OR

REPLACED.

3795 BELTS ARE LOOSE AND SLIP A

LITTLE DURING LOADING.

3893 DRIVE BELT ARE SQUEALING AND

NEED TO BE ADJUSTED.

4286 BELTS ARE LOOSE A SQUEALING.

4848 AIR COMPRESSOR IS MAKING A

LABORED SCREACHING SOUND.

PROBLEM TYPE: Controls

3814 OIL PRESSURE GAUGE INDICATES

.30 PSI WHEN COMPRESSOR IS

SHUT DOWN.

3997 CHECK TRS-2 (TIME DELAY SW

WHICH SHUTS DOWN COMPRESSOR

AFTER IT UNLOADS FOR 5 MIN.)

4706 COMPRESSOR 0ID-NOT START AND

LOAD FROM THE LAG/AUTO

POSITION.

NORMAL BELT WEAR.

FOUND UNIT TO TURN ON AND

LOAD WHEN THE PRESSURE SWITCH

WAS BLED OFF.

READJUSTED BELT TENSION.

COMPRESSOR OPERATED SAT AFTER

ADJUSTING.

VALVED OUT PRESSURE SWITCH AND

BLED OFF PRESSURE SLOWLY TO

VERIFY COMPRESSOR WOULD LOAD

WHEN SYSTEM PRESSURE DROPPED.

PROBLEM TYPE: Cooling

3481 CHEMICAL CLEANING OF WATER

JACKETS IS NEEDED ON AIR

COMPRESSORS.
82

Table C.1 (cont d)

IPRDS SERVICE COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE CONCERN

3509 COMPRESSOR OVERHEATED SEVERLY.

SUSPECT FAILURE OF SOLENOID

VALVE FOR COOLING WATER.

3612 COMPRESSOR IS RUNNING 15-30

DEGREES F HOTTER THAN EITHER

OF OTHER COMPRESSORS.

3997 THE COOLING WATER SUPPLY

SOLENOID VALVE IS NOT SHUTTING

OFF COOLING WATER.

4047 FOUND WATER JACKET PATHS

RESTRICTED. JACKETS NEED

FLUSHED.

4761 TEMPERATURE OF COOLING WATER

HAS BEEN ABNORHALLY HIGH

(APPROX 123F).

PROBABLE CAUSE ACTION TAKEN

COOLING WATER LINES PLUGGED. CROSS TIED WATER AND AIR AND

FLUSHED AFTER COOLER,

COMPRESSOR JUG, & DISCHARGE

PIPE OUT. LOTS OF MUD BLOWN.

PROBLEM TYPE: Heat Exchanger

4391 INSTRUMENT AIR COMPRESSOR

AFTER COOLER IS LEAKING 

DROP/3 MIN FROM WEEP HOLE.

AFTERCOOLER TAKEN TO FA3 SHOP.

TUBE BUNDLE CLEANED. PACKING

O-RINGS CHANGED. REPLACED

GASKETS, REINSTALLED. OK.

EPOXY REPAIRED PITTED PLACES,

MACHINED 1/8" OFF INSIDE TUBE

PLATE. INSTALLED NEW O-RINGS,

PRESSURE CHECKED.

4913 LEAKAGE ON AFTERCOOLER AT

TELLTALE HOLE.

AGE WATER PROBLEM.

PROBLEM TYPE: Leak

2937 OIL LEAKS FROM COVER PLATE.

3351 SMALL OIL AND WATER LEAK

CAUSES MESS ON FLOOR. IT IS

FROM UNDETEF4INED SOURCE.
83

Table C.1 cont'd)

IPRDS SERVICE COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE CONCERN

3797 COMPRESSOR HAS A SMALL AIR

LEAK AT OISCHARGE GASKET.

4059 VERY SMALL OIL LEAK WITH VERY

SLOWLY LOWERING OIL LEVEL.

PROBABLE CAUSE ACTION TAKEN

4096 AFTERCOOLER HAS A LEAK AT

THE FLANGE.

4298 THE UPPER-CENTER DISCHARGE

VALVE COVER IS LEAKING FROM

GASKET.

4700 AIR LEAK ON CYLINDER HEAD. PUT

TACK TAPE ON THAT CYLINDER.

5023 INLET FLANGE TO 4SW COOLING

SV4747 IS LEAKING. TRIED TO

TIGHTEN FLANGE.

LEAKING AIR FROM LEAD SEAL

AROUND VALVE BOLT.

BAD UNION SEALING SURFACES.

REPLACED LEAD SEAL.

REPLACED UNION. CHECKED FOR

LEAKS. NO LEAKS. '

PROBLEM TYPE: echanical

.5408 1 INSPECTION SHOWED WATER IN

CYLINDER. EEDS TO BE TORN

DOWN FOR INSPECTION.

3765 COMPRESSOR, WHEN LOADED,

"POPS" ABNORMALLY FROM TOP

AREA.

3816 UNIT NEEDS OIL ADDED TO IT.

4012 COMPRESSOR RUNS FREELY

UNLOADED; HOWEVER WHEN LOADED

IT RUNS HARD.

PROBLEM TYPE: Motor

3760 COMPRESSOR MOTOR SOUNDS LIKE

THERE MAY BE A BEARING GOING

BAD.

4109 MOTOR BEARING NOISY.
V

84

Table C.1 (cont'd)

IPRD$ SWRVICE COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE CONCERN PROBABLE CAUSE ACTION TAKEN

PROBLEM TYPE: Unknown

3115 WILL NOT RUN.

5005 COMPRESSOR WILL NOT START IN

'HAND' POSITION, SUPPLY

BREAKER KEEPS TRIPPING.

TOOK OHMS READINGS AT SWITCH.

OK. MOTOR WINDINGS OK. MEG

MOTOR > 1000 NO"IS - TURN

POWER ON GOOD VOLTAGE 490 V.

PROBLEM TYPE: Unloader

3005 LOADING SOLENOID VALVE IS NOT

OPERATING PROPERLY.

3130 LOADING SOLENOID ONLY WORKS

OCCASIONALLY, NEEDS TO BE

REPLACED OR REPAIRED.

3135 LOADING SOLENOID STICKS

SO COMPRESSOR WILL NOT LOAD.

3153 UNIT MAKES WHISTLING SOUND

AFTER IT UNLOADS. SUSPECT A

BAD LOADING VALVE.

3326 SOLENOID FAILED. COMPRESSOR

WILL NOT LOAD BY ITSELF.

3823 SOLENOID IS MAKING ABNORMAL

NOISE WHEN COMPRESSOR LOADS.

SOLENOID HAS QUIT WORKING.

3997 UNLOADER SOLENOID IS

GETTING HOT AND CHATTERING.

4092 THE COMPRESSOR LOADING

SOLENOID DOES NOT WORK.

4569 LOAD VALVE SAD AND FITTING ON

RIGHT SIDE LEAKS BY. LEAK IS

EXCESSIVE.

FOUND UNLOADER SOLENOID TO BE

CHATTERING.

REPLACED SOLENOID.
35

Table C.1 (cont'd)

IPRDS SERVICE COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE CONCERN PROBABLE CAUSE ACTION TAKEN

COMPRESSOR "C"

PROBLEM TYPE: Belt

3178 COMPRESSOR HAS LOOSE BELTS.

3198 BELTS ARE LOOSE.

3257 BELTS ARE LOOSE AND FLAP WHEN

COMPRESSOR IS LOADED.

3893 DRIVE BELTS ARE SQUEALING

AND NEED TO BE ADJUSTED.

PROBLEM TYPE: Controls

3814 OIL PRESSURE GAUGE INDICATESt! '

30 PSI WHEN COMPRESSOR IS

SHUT DOWN.

4151 WHEN COMPRESSSOR UNLOADS THE

LOADING PRESSURE INDICATED ON

THE LOCAL GAUGE IS ABNORMAL.

PROBLEM TYPE: Coolng;

2999 TEST AND REPLACE RELIEF VALVE

ON COMPRESSOR WATER JACKET.

3473 CHEMICAL'CLEANING OF WATER

JACKETS IS NEEDED.

3485 UNIT COOLING JACKET NEEDS

TO BE CHEMICALLY CLEANED.

4055 WATER JACKET PATHS NEED

FLUSHED.
86

Table C.1 (cont'd)

IPROS SERVICE COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE I CONCERN

PROBLEM TYPE: Heat Exchanger

3126 TRAP PASSES AIR THROUGH. DOES

NOT WORK, SO IS ISOLATED.

3291 AFTER COOLER LEAKED BACK INTO

COMPRESSOR CYLINDER.

3297 BAD RUBBER PACKING RINGS ARE

CAUSING AIR LEAKAGE OUT OF

TELL-TALE HOLES IN COOLER.

3338 MOISTURE TRAP BLOWS AIR

CONTINUOUSLY.

4356 ABOUT I DROP/MIN LEAKAGE FROM

UPPER WEEP HOLE ON AFTERCOOLER.

PROBABLE CAUSE ACTION TAKEN

REMOVED AFTERCOOLER, REPLACED

O-RINGS, INSTALLED WITH NEW

GASKETS.

PROBLEM TYPE: Leak

3611 SMALL WELL WATER LEAK ON

PIPING DOWNSTREAM OF SV4752.

3721 PIPE .FITTING ON WELL WATER

COOLING LINE UPSTREAM OF WATER

SHUTOFF SOLENOID VALVE LEAKS.

PROBLEM TYPE: Mechanical

3310 COMPRESSOR MAKING UNUSUAL

NOISES.

3349 HAS VERY LOUD CHATTER.

3597 UNIT MAKES LOUD HAMMERING

NOISE WHEN IN OPERATION.

3713 COMPRESSOR IS NOISY.
87 a

Table C1 (cont'd)

IPRDS SERVICE COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE CONCERN

4355 COMPRESSOR IS MAKING A LOUD

TICKING/HAMMERING NOISE FROM

THE INTAKE SIDE.

PROBABLE CAUSE ACTION TAKEN

4374 AIR COMPRESSOR FOUNDATION NUTS

LOOSE AND AIR COMPRESSOR IS

VI BRATING.

PROBLEM TYPE: Motor

3718 PULLEY END MOTOR BEARING IS

MAKING NOISES LIKE IT WILL

FAIL SOON.

PROBLEM TYPE: Operational

4488 COMPRESSOR WOULD NOT LOAD

AUTOMATICALLY HEN IT SHOULD

HAVE.

UNIT WOULD NOT LOAD. FOUND

V593 WAS SHUT, SHOULD BE OPEN.

HAD AUX OPERATOR OPEN V593.

PROBLEM TYPE: Unknown

3710 FOUND SUPPLY BREAKER TRIPPED.

LARGE ACCUMULATION OF WATER ON

FLOOR.

PROBLEM TYPE: Unloader

3598 SOLENOID LOADING VALVE FOR

COMPRESSOR IS ALLOWING AIR

TO PASS TROUGH.

3717 BREAKER WAS TRIPPED OFF. IT

WOULD SEEM COMPRESSOR IS NOT

LOADING PROPERLY.

3718 TROUBLE-SHOOTPROBLEM WITH

UNLOADING AIR CONTROL SYSTEM.

4825 COMPRESSOR WAS CYCLING. COIL OR CORE SPRING WEAKENED. REPLACED LOADING SOLENOID.
88

Table C.1 (cont'd)

IPRDS SERVICE COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE CONCERN PROBABLE CAUSE

PROBLEM TYPE: Valve

ACTION TAKEN

3359 SUCTION CHECK VALVES ARE NOT

OPERATING PROPERLY.

4460 COMPRESSOR MAKING EXCESSIVE

NOISE. SUSPECT SUCTION VALVE

IS STICKING.

FOUND SUCTION VALVE HAS COME

LOOSE BROKE APART SCORING

PISTON BEYOND REPAIR.

REPLACED PISTON, CLEANED

CYLINDER, REPLACED

RINGS(PISTON), VALVES(INTAKE 

DISCHARGE), PACKING. SET

PISTON CLEARANCE.

I) r

I'I

: Jt-
89

Table C.2

IPRDS DRYER MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE CONCERN ACTION TAKEN

PROBLEM TYPE: Controls

3312 REQUEST CHECK OF INSTRUMENT

AIR DRYER. HEATERS APPEAR TO

BE OFF.

3599 RIGHT CHAMBER-OUTLET TEMP

READS >5500F.

3717 GOT HI TEMP ALARM WHILE RIGHT

DESSICANT CHAMBER WAS IN

HEATING MODE.

3830 CHECK CALB. OF TI-3045 (RIGHT

CHAMBER INLET TEMP). READS 5F

LESS THAN LEFT CHAMBER.

3914 RIGHT CHAMBER OUTLET TEMP

READS >550 DEGREES. NEEDS

NEW STARTING UNIT.

4069 THE HIGH HUMIDITY. ALARM

KEEPS COMING IN AND OUT

RAPIDLY.

PROBLEM TYPE: Desiccant or Filter

3139 8-10 PSI ACROSS AIR DRYER

AFTER FILTER AND ALSO STANDBY

FILTER.

3493 EVALUATE EXCESSIVE P ACROSS

THE INSTR AIR DRYER.

3810 PREV. MAINT. PROCEDURE REPLACED AIR FILTER.CARTRIDCE.

3817 PREV. MAINT. PROCEDURE DESICCANT CHANGED.
90

Table C.2 (cont'd)

IPRDS DRYER MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE CONCERN ACTION TAKEN

3887 INSPECT AFTER FILTER

CARTRIDGES FOR CAUSE OF

DESSICANT LEAKAGE.

3977 PREV. MAINT. PROCEDURE AFTER FILTERS WERE BAD - NO

REPLACEMENTS - CLEANED THE OLD

ONE - CHANGED FILTERS.

PROBLEM TYPE: Leak

3305 1/4 INCH COPPER TUBING HAS A

HOLE IN IT - BLOWING OUT AIR.-

3745 ON RIGHT CHAMBER, LOWER

PIPE HAS A SMALL AIR LEAK.

PROBLEM TYPE: Valve

2999 INST AIR DRYER PISTON &

LINKAGE ASSEMBLY DOES NOT

MOVE AS SIGNALED.

3738 THE LOWER 3-WAY VALVE THAT

SELECTS THE CHAMBERS HAS AN

AIR LEAK.

3748 THE SECOND SOLENOID VALVE FROM

THE TOP ON THE LEFT SIDE...

(Data base truncated text.)

3864 1T-53 INSTRUMENT AIR DRYER,

BOTTOM 3-WAY VALVE BETWEEN THE

TWO DESICANT .... (Data base

truncated text.)

3985 PURGE FLOW ADJUSTMENT

REGULATOR WILL NOT CHANGE

PURGE RATE.
91

Table C.2 (cont'd)

IPRDS DRYER MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE CONCERN CTION TAKEN

4399 COMPLETE INSTALLATION AND

TESTING OF NEW INSTRUMENT AIR

DRYER.

PROBLEM TYPE: Desiccant or Filter

4539 THE LEFT CHAMBER OF DRYER

APPEARS TO BE CLOGGED.

4937 PREV. MAINT. PROCEDURE

Al

CHANGED DESSICCANT PER VENDOR

MANUAL.

REPLACED BYPASS AND MAIN AFTER

FILTERS.

PROBLEM TYPE: Leak

4413 BOTTOM 4-WAY CV ON BACK OF OLD

INST AIR DRYER HAS AIR LEAK

AROUND STEM.

4476 THERE IS AN AIR LEAK ON THE

PIPING GOING INTO THE AIR ,

DRYER HEATER.

4685 IT APPERAS THAT THE INLET'

VALVE MANIFOLD IS LEAKING AT

THE LEFT CHAMBER.

w

PROBLEM TYPE: Valve

4747 TROUBLESHOOT AND REPAIR THE

INLET AND/O OUTLET VALVES FOR

STICKING.

4780 INLET AND PURGE EXHAUST VALVES

HAVE DAMAGED CYLINDERS, RODS,

ETC.

SNOOPED PACKING GLAND, NO

LEAKAGE FOUND. SNOOPED FLANGES

AND FOUND LEAKS ON TWO OF THE

FOUR FLANGES. TIGHTENED.

REPLACED PIPING AND FITTING.

NOTHING.

CLEANED VALVES UP, POLISHED

CYLINDER BORES, PISTONS AND

RODS. WORKING SAT NOW.

REPLACED INLETS & EXHAUSTVALVES.
93

Table D.1

I Table D.2

APPENDIX D

UTILITY NUCLEAR PLANT AIR COMPRESSOR

AND DRYER MAINTENANCE CALLS

Utility Nuclear Plant Air Compressor Maintenance

.Calls (by Problem Type

Utility Nuclear Plant Air Dryer Maintenance

Calls (by Problem Type) .

95

121
I

95

Table D.1

UTILITY NUCLEAR PLANT AIR COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE PROBLEM

SERVICE/CONTROL COMPRESSOR "A"

PROBLEM TYPE: Controls

09/29/85 Repair or replace hour meter.

ACTION TAKEN

Replaced hour'meter.

PROBLEM TYPE: Heat Exchangers and Traps

12/18/84 Moisture trap, and possibly

line to it, appears to be

clogged.

03/25/85 Excessive'amount of water

inside intercooler.

Removed and cleaned trap.

Checked tube bundle for leaks

and replaced.

PROBLEM TYPE: Leaks

06/07/81 High pressure end plate gasket

blown.

07/21/81 Blown gasket on high pressure

head.

11/13/81 Air leak on high pressure

cylinder.

04/13/82 Leaking inspection plate

gasket.

04/18/82 Oil leak from motor housing.

06/17/82 Casket leaking oil between

casing and motor.

08/01/82 Valve cover gasket on high'

pressure head is leaking air.

08/14/82 High pressure head gasket

leaking.
96

Table D.1 (cont'd)

UTILITY NUCLEAR PLANT AIR COMPRESSOR

(BY PROBLEM TYPE)

MAINTENANCE CALLS

DATE PROBLEM ACTION TAKEN

08/27/82 High pressure gasket needs

replacing.

04/25/83 Air leak on high pressure

head.

11/16/83 Oil filter leaking.

05/31/84 Crankcase seals leaking.

02/21/85 Oil leak on top of crankcase.

10/31/86 Low and high pressure seals

blown. Compressor was filled

with water.

03/07/87 On startup, compressor tripped

on low oil pressure. Water

spurting from connecting rod

cover vent hole on high

pressure end.

08/23/87 High pressure head has blown

gasket.

12/20/87 Low pressure side filled with

water.

Replaced crankshaft seal,

leaking gaskets, and oil sight

glass.

Replaced gasket.

Installed new seals, oil

filter, and port plate.

Installed new oil filter,

gaskets and intake and exhaust

valves.

Cleaned, inspected and

reassembled compressor.

Replaced intercooler filter.

Installed new oil filter,

stuffing box piston head

valves oil and air packing.

Filled with new oil.

PROBLEM TYPE: Mechanical

11/06/81 Install sleeves in high

pressure heads.

01/15/82 Compressor was rebuilt.

12/18/84 Repair rip in copper air line. Replaced copper air line.
97

Table D.1 (cont'd)

UTILITY NUCLEAR PLANT AIR COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE PROBLEM ACTION TAKEN

09/23/85 Coupling broken. Fabricated and installed hubs.

PROBLEM TYPE: Piston Rings

10/31/87 Blowthrough at high pressure

shaft seal.

Rebuilt low pressure valve and

unloaders. Replaced gaskets,

o-rings, and oil filter.

Installed new high pressure

cylinder.

PROBLEM TYPE: Seals

06/07/81 Bad oil seal on high pressure

end.

01/19/84 Repair high pressure shaft

seal.

02/15/84 Compressor uses excessive

amount of oil and has unusual

amount of air in oil.

05/31/84 Crankcase seals leaking. Replaced crankshaft seal,

leaking gaskets, and oil sight

glass.

11/24/84 High pressure shaft seal is

blown.

Replaced bad low pressure

valves, unstuck unloader,

replaced air filter.

01/19/85 Air leak at high pressure

seal.

02/01/85 High pressure rod seal leaking

through.

05/27/85 High pressure seal leaking.

06/11/85 Large amount of air bubbles in

crankcase oil.

Installed new packing.

Replaced seal.

Repacked component.
98

Table D.1 (cont'd)

UTILITY NUCLEAR PLANT AIR COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE PROBLEM ACTION TAKEN

09/21/85 Packing leaks.

10/31/85 Air leak around shaft packing.

10/31/86 Low and high pressure seals

blown. Compressor was filled

with water.

01/21/87 High pressure seal leakage.

10/18/87 Second stage air blowby from

weep hole.

10/31/87 Blowthrough at high pressure

shaft seal.

12/20/87 Low pressure side filled with

water.

07/07/88 High pressure end leakage into

crosshead area - seal leaks.

Repacked.

Installed new packing.

Installed new seals, oil

filter, and port plate.

Installed new packing.

Replaced high pressure

packing.

Rebuilt low pressure valve and

unloaders. Replaced gaskets,

o-rings, and oil filter.

Installed new high pressure

cylinder.

Replaced intercooler filter.

Installed new oil filter,

stuffing box piston head

valves oil and air packing.

Filled with new oil.

Installed packing.

PROBLEM TYPE: Valves

06/07/81 Bad valves on high pressure

end.

10/08/82 Intercooler safety valve is

relieving, indicating bad high

pressure valves.

02/05/83 Low pressure valve making

noise.

10/03/83 High pressure reed valves are

leaking through.
99

UTILITY NUCLEAR

Table D.1 (cont'd)

PLANT AIR COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE - PROBLEM

* 10/30/84 High pressure side making

unusual noise.

11/24/84 ligh pressure shaft seal is

blown.

ACTION TAKEN

Replaced valve.

Replaced bad low pressure

valves, unstuck unloader,

replaced air filter.

12/02/84 Intercooler relief valve

lifting.

01/25/85 Air is leaking out the intake

filter. Replace valves.

06/11/85 Intake valves on low pressure

side need repairs

Replaced intake valves on low

pressure end.

09/23/86 Valves on high pressure

cylinder leaking through,

causing relief valve to lift.

03/07/87 On startup, compressor tripped

on low oil pressure. Water

spurting from connecting rod

cover vent hole on high

pressure end.

10/31/87 Blowthrough at high pressure

shaft seal.

12/20/87 Low pressure side filled with

water.

01/31/88 Compressor will not follow

load.

Installed 2 intake valves with

unloaders and 2 exhaust

valves.

Installed new oil filter,

gaskets and intake and exhaust

valves.

Rebuilt low pressure valve and

unloaders. Replaced gaskets,

o-rings, and oil filter.

Installed new high pressure

cylinder.

Replaced intercooler filter.

Installed new oil filter,

stuffing box piston head

valves oil and air packing.

Filled with new oil.

Removed and replaced unloader

VB.
t0o

Table D.1 (cont'd)

UTILITY NUCLEAR PLANT AIR COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE I PROBLEM

SERVICE/CONTROL COMPRESSOR "B"

PROBLEM TYPE: Heat Exchangers and Traps

09/26/81 Suspect intercooler leak in

rod oil collection tank.

09/15/86 Pressure test intercooler tube

bundle for leak.

02/06/87 Water leaking into high

pressure side.

ACTION TAKEN

l

Rebuilt compressor and cleaned

out moisture trap.

PROBLEM TYPE: Leaks

06/16/82 Oil leaking from motor

housing.

07/14/83 Oil leaking from compressor

through motor vents.

11/16/83 Oil leak at compressor

crankcase below oil filter.

03/14/84 Oil leaks through both high

pressure and low pressure

sides.

09/21/84 Water leak around high

pressure side flange.

11/29/84 High pressure air leak.

01/14/85 Water leak at high pressure

head piping.

03/28/85 Leak at discharge flange on

high pressure end.

06/28/85 Oil leaks in crankcase.

Tightened nipple. Repaired

leak in solder joint.

Replaced gasket.
101

Table D.1 (cont'd)

UTILITY NUCLEAR PLANT AIR COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE PROkLEM

09/21/85 Replace gasket on second

Stage.

04/09/86 Flange leaks at valve covers

and ntercooler inlet.

ACTION TAKEN

Replaced gasket.

Installed-new gaskets and rod

packing. Added 1 gal oil.

PROBLEM TYPE: Mechanical

11/06/81 Install sleeves in high

pressure heads.

03/26/82 Overhaul compressor.

02/05/83 Rebuild compressor and replace

high pressure head.

07/08/85 Blown seal on high pressure

side.

05/01/86 High pressure valves leaking

back, causing intercooler

relief valve to lift.

05/22/86 Replace warped port plate or

high pressure end.

11/09/86

02/06/87 Water leaking into high

pressure side.

05/27/87 Low pressure end has excessi

oil leakage and noisy valves

Installed new valves and

cylinder. Replaced oil

scraper rings and piston rod

packing.

Broken mounting bolts; debris

in valves. Installed new high

pressure intake and exhaust

valves.

Installed new port plate,

inner cylinder assembly,

piston rings, intake and

exhaust valves, packing, and

gaskets.

Rebuilt compressor.

RebuilL compressor and cleaned

out moisture trap.

ve Installed main bearing housing

i. oil pump motor bearing housing

seals and piston packing.

Added oil.
102

Table D.1 (cont'd)

UTILITY NUCLEAR PLANT AIR COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE PROBLEM ACTION TAKEN

PROBLEM TYPE: Piston Rings

05/22/86 Replace warped port plate on

high pressure end.

Installed new port plate,

inner cylinder assembly,

piston rings, intake and

exhaust valves, packing, and

gaskets.

PROBLEM TYPE: Seals

04/05/82 Excessive leakage from high

pressure seals.

10/08/82 High pressure shaft seal

-teaking,-air.

01/26/84 Repair high pressure shaft

seal.

07/18/84 Excessive oil usage. Leaks

past ring seal in both high

and low pressure ends.

09/12/84 Repair high pressure air seal.

02/21/85 High pressure rod seal leaking

through.

05/29/85 High pressure seal leaking.

07/08/85 Blown seal on high pressure

side.

04/09/86 Flange leaks at valve covers

and ntercooler inlet.

Replaced packing.

Replaced packing.

Repacked.

Replaced packing.

Installed new valves and

cylinder. Replaced oil

scraper rings and piston rod

packing.

Installed new gaskets and rod

packing. Added 1 gal oil.
103

Table D.1 (cont'd)

UTILITY NUCLEAR PLANT AIR COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE PROBLEM ACTION TAKEN

05/22/86 Replace warped port plate on

high pressure end.

05/27/87 Low pressure end has excessive

oil leakage and noisy valves.

Installed new port plate,

inner cylinder assembly,

piston rings, intake and

exhaust valves, packing, and

gaskets.

Installed main bearing housing

oil pump motor bearing housing

seals and piston packing.

Added oil.

PROBLEM TYPE: Valves

06/06/81 Bad valves on high pressure

end.

09/23/81 High pressure feather valves

allow air to flow through when

compressor unloaded.

09/26/81 Intercooler relief valve ;

relieving intermittently.

05/20/85 Intake valves are bad.

07/08/85 Blown seal on high pressure

side.

05/01/86 -High pressure valves leakii

back, causing intercooler

relief valve to lift.

05/22/86 Replace warped port plate 

high pressure end.

Replaced unloader control

valve and low pressure valves.

Installed new valves and

cylinder. Replaced oil

scraper rings and piston rod

packing.

Ig Broken mounting bolts; debris

in valves. Installed new high

pressure intake and exhaust

valves.

on Installed new port plate,

inner cylinder assembly,

piston rings, intake and

exhaust valves, packing, and

gaskets.
104

Table D.1 (cont'd)

UTILITY NUCLEAR PLANT AIR COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE PROBLEM ACTION TAKEN

08/11/88 Compressor will not build

pressure when full loaded.

Broken intake valve on

pressure end. Replaced

intake and 6 discharge

on low pressure end.

low

6

valves

SERVICE/CONTROL COMPRESSOR "C"

PROBLEM TYPE: Controls

01/15/82 Charging motor appears to be

bad.

PROBLEM TYPE: Leaks

04/13/82 High pressure valve cover

gaskets leaking air. Need to

replace seals.

04/14/82 High pressure section leaking

air.

05/05/83 Air leak on high pressure

head.

Replaced gasket.

06/14/86 High pressure cylinder head

has air leak.

07/29/87 Discharge head has blown

gasket.

08/22/87 Suspect water leak into high

pressure end; lots of water

from moisture trap on

aftercooler.

11/20/87 Air leak on distance piece

cover plate.

Replaced worn gaskets and

packing.

Replaced gaskets. Installed

new intake and discharge

valves and oil and air

packing.

Disassembled high pressure end

for inspection. Replaced

inner portplate and gasket.

Cleaned trap.

Replaced high pressure side

cover gasket.
105

Table Dl (cont'd)

UTILITY NUCLEAR PLANT AIR COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE PROBLEM

12/07/87 Air leak on high pressure

unloader valve.

PROBLEM TYPE: Mechanical

11/06/81 Install sleeves in high

pressure heads.

03/05/82 High oil temperature; high oil

pressure.

05/06/83 Compressor noisy when starting

up or shutting down.

PROBLEM TYPE: Piston Rings

08/26/85 Compressor will only

half-load.

PROBLEM TYPE: Seals

04/13/82 High pressure valve cover

gaskets leaking air. Need to

replace seals.

11/12/82 Packing blown on discharge.

11/07/83 High pressure shaft seal is

leaking.

01/20/84 Repair high pressure shaft

seal.

09/12/84 Repair high pressure shaft

seal.

12/03/84 High pressure shaft seal is

blown.

08/26/85 Compressor will only

half-load.

ACTION TAKEN

Tightened fitting on unloader

line.

Installed new piston rings and

rod seals.

Replaced rafoil packing.

Replaced packing.

Installed new piston rings and

rod seals.
106

Table D.1 (cont'd)

UTILITY NUCLEAR PLANT AIR COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE PROBLEM ACTION TAKEN

09/21/85 Packing leaks.

06/14/86 High pressure cylinder head

has air leak.

03/11/87 Bad seal on high pressure

cylinder.

07/29/87 Discharge head has blown

gasket.

10/27/87 Loading valve is sticking

open.

Installed new packing.

Replaced worn gaskets and

packing.

Installed new packing in high

pressure end.

Replaced gaskets. Installed

new intake and discharge

valves and oil and air

packing.

Replaced inlet and discharge

valves and piston rod packing.

Cleaned unloader valves.

PROBLEM TYPE: Valves

09/20/81 Intercooler relief valve

relieving on high pressure.

09/20/81 High pressure feather valves

stuck, causing intercooler

relief valve to lift.

09/30/81 High pressure reed valves are

apparently stuck open.

11/12/82 Suspect low pressure end needs

valves.

02/05/83 Low pressure valve making

noise.

05/09/84 Compressor makes loud knocking

noise when half loaded.

09/23/84 Intercooler pressure is low

and erratic.

Replaced low pressure valve.

Replaced intake valve.
107

Table D.1 (cont'd)

UTILITY NUCLEAR PLANT AIR COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE ;

01/18/85

PROBLEM

Intake valve problem.

ACTION TAKEN

Replaced low pressure intake

and exhaust valves.

06/14/85 Air blowing back through

intake filter when loaded.

09/15/86 Suspect reed valve is hanging

open, causing over-pressure in

intercooler.

Replaced gaskets and installed

new pilot valve.

Replaced 2 worn high pressure

discharge valves.

10/29/86 When unloaded or half-loaded,

it appears that high pressure

valves are leaking back,

causing intercooler relief

valve to lift.

07/29/87 Discharge head has blown

gasket.

08/31/87 Unloader on high pressure end

blowing water and sticking

open.

10/27/87 Loading valve is sticking

open.

Replaced gaskets. Installed

new intake and discharge

valves and oil and air

packing.

Unloader valves disassembled

and cleaned.

Replaced inlet and discharge

valves and piston rod packing.

Cleaned unloader valves.

CONTROL/SERVICE COMPRESSOR "D"

PROBLEM TYPE: Controls

06/10/86 Charging spring motor does not

work; spring must be manually

charged to close ACB.

Resurfaced contacts and

lubricated gears on charging

spring motor.
108

Table D.1 (cont'd)

UTILITY NUCLEAR PLANT AIR COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE PROBLEM ACTION TAKEN

PROBLEM TYPE: Heat Exchangers and Traps

11/10/82 RCW leakage into aftercooler

shell.

12/10/85 Air and water leak at

intercooler tube bundle

inspection plate.

03/17/87 Aftercooler head gasket blown;

suspect blown tube.

Cleaned trap. Installed new

low pressure discharge valves

and new pilot valve.

Installed upper and lower tube

bundles with gaskets.

PROBLEM TYPE: Leaks

02/16/84 Air leak where discharge pipe

bolts to compressor.

06/19/84 High pressure chamber has

leak.

08/30/84 High pressure side panel

leaking air.

09/12/84 High pressure discharge flange

leak.

09/14/84 High pressure reed valve has

blown gasket.

11/08/84 Air leak around flange.

06/09/85 Low pressure side leak at

intercooler flange.

06/25/85 Oil leak at oil filter.

08/20/85 Water leak in low pressure

head.

Replaced gasket.

Replaced gasket on high

pressure discharge cover.

Replaced gasket.

Installed new valves and cover

gaskets.

Replaced gaskets.

Replaced oil filter seal.

Cleaned trap. Cleaned valves.

Replaced rings, seals, and

wipers. Set piston clearance.

09/24/86 Air leak at intercooler.
109

Table D.l (cont'd)

UTILITY NUCLEAR PLANT AIR COMPRESSOR - (BY PROBLEM TYPE)

MAINTENANCE CALLS

DATE

10/31/86

PROBLEM ACTION TAKEN

High pressure head has bolt

leaking air.

Installed new discharge gasket

and packing and tightened

bolts.

03/24/87 Oil leaking from breather cap

above oil filter.

04/22/87 Compressor dirty and has oil

leak.

05/29/87 Oil loss. Suspect rod packing

not correctly broken in.

07/01/87 Blown high pressure head

gasket.

07/14/87 Water dripping from suction

header after compressor idle

for 8 hours.

10/31/87 Wrong type of gasket material

on inner port plate. Gasket

blew out.

10/31/87 Oil leak.

08/01/88 Blown high pressure cylinder

-head gasket.

Changed oil and oil filter,

tightened all bolts around oil

pump.

Cleaned compressor and

replaced some parts.

Replaced oil scrapers.

Replaced gaskets.

Replaced gasket.

Installed new head gasket and

intercooler gaskets. Cleaned

and tested trap. Replaced

rusty high pressure discharge

valves.

Rebuilt valves and cleaned all

parts. Replaced high pressure

piston and head, discharge

valves, and cover plates.

Replaced gaskets.

Replaced intercooler gaskets

and oil pump cover plate.

Replaced High pressure

discharge valve cover gasket

and pipe gasket.

PROBLEM TYPE: Mechanical

04/25/83 Loud knocking in suction end

of compressor.

09/24/86 Worn internals. Air compressor rebuilt.
110

Table D.l (cont'd)

UTILITY NUCLEAR PLANT AIR COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE PROBLEM ACTION TAKEN

10/06/86 Loud knocking noise on low

pressure end.

PROBLEM TYPE: Piston Rings

05/31/84 Oil leak from

housing.

08/20/85 Water leak in

head.

08/20/85 High pressure

leaking.

08/20/85 High pressure

leaking.

10/31/87 Wrong type of

on inner port

blew out.

piston rod

low pressure

shaft seal

reed valve

gasket material

plate. Casket

Replaced rings and packing.

Cleaned trap. Cleaned valves.

Replaced ringsI seals, and

wipers. Set piston clearance.

Replaced rings, seals and

wipers. Set piston clearance.

Replaced

wipers.

rings! seals and

Set piston clearance.

Rebuilt valves and cleaned all

parts. Replaced high pressure

piston and head, discharge

valves, and cover plates.

Replaced gaskets.

PROBLEM TYPE: Seals

12/08/82 High pressure

bad.

seal appears . .n

04/25/83 High pressure seal

replacement.

11/05/83 High pressure

leaking.

rod seal is

01/19/84 High pressure

leaking.

shaft seal Replaced packing.

02/18/84 Repair high pressure rod seal.

05/31/84 Oil leak from piston rod

housing.

Replaced rings and packing.
III

Table D.1 (cont'd)

UTILITY NUCLEAR PLANT AIR COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE

08/20/85

08/21/85

08/26/85

PROBLEM ACTION TAKEN

Water leak in low pressure

head. High pressure shaft

seal leaking. High pressure

valve leaking.

High pressure seal leak.

Scraper rings need replacing.

Cleaned trap. Cleaned valves.

Replaced rings1 seals, and

wipers. Set piston clearance.

Replaced high pressure seal.

Installed new packing and

scraper rings.

Installed new packing.

Replaced oil scrapers.

Replaced gaskets.

09/21/85 Packing leaks.

05/29/87 Oil loss. Suspect rod packing

not correctly broken in.

09/28/87 Excessive air leakage from

high pressure packing.

12/19/87 Air blowing from piston rod

packing on high pressure end.

04/01/88 Excessive air leakage from

high pressure rod packing.

Replaced

packing.

Replaced

packing.

high pressure

high pressure

Replaced packing.

PROBLEM TYPE: Valves

06/02/83 Repair loose valve on high

pressure end.

05/09/84 High pressure valves leaking,

causing intercooler to

relieve.

09/14/84 High pressure reed valve has

blown gasket.

11/15/84 Bad high pressure valves.

Installed new valves and cover

gaskets.

Installed new valve.

/ 12/10/85 Air and water leak at

intercooler tube bundle

inspection plate.

Cleaned trap. Installed new

low pressure discharge valves

and new pilot valve.

/
112

Table D.1 (cont'd)

UTILITY NUCLEAR PLANT' AIR COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE PROBLEM

12/01/86 Air leaking by unloader on

high pressure end of

compressor causes intercooler

relief valve to open.

07/14/87 Water dripping from suction

header after compressor idle

for 8 hours.

ACTION TAKEN

Removed and rebuilt 3-way

valve to unloader.

Installed new head gasket and

intercooler gaskets. Cleaned

and tested trap. Replaced

rusty high pressure discharge

valves.

10/31/87 Wrong type of

on inner port

blew out.

gasket material

plate. Gasket

Rebuilt valves and cleaned all

parts. Replaced high pressure

piston and head, discharge

valves, and cover plates.

Replaced gaskets.

AUXILIARY COMPRESSOR AA

PROBLEM TYPE: Belts

01/10/85 Adjust or replace belts.

PROBLEM TYPE: Controls

06/24/83 No dead band for loading and

unloading.

PROBLEM TYPE: Heat Exchangers and Traps

02/22/85 Clean aftercooler tubes.

PROBLEM TYPE: Leaks

07/03/81 Instrument line has hole in it

and is leaking water.

Removed heads and cleaned.

05/07/82 Water leak at head.
113

Table D.1 (cont'd)

UTILITY NUCLEAR PLANT AIR COMPRESSOR

(BY PROBLEM TYPE)

MAINTENANCE CALLS

DATE PROBLEM

02/05/83 Air leak at upper section of

cylinder cover.

02/19/83 Leaking gasket.

04/27/83 Aftercooler inlet union leaks

air.

05/18/83 Air leak at head gasket.

07/04183 Water in oil.

09/07/83 Various fittings are leaking

air.

10/18/83 Air leak at flange plate on

side of compressor.

04/01/84 Head gasket is leaking.

05/31/84 Leaking head gasket.

09/06/84 Various air leaks.

02/12/85 Casket on side near top of

head is still leaking.

02/21/85 Replace gaskets under top and

side plates.

05/24/85 Excessive leak at head gasket.

10/21/85 Leak at gasket.

ACTION TAKEN

Replaced side cover gasket.

Tightened head gasket bolts.

Tightened pate bolts.

Installed hold down bars and

new gaskets.

Replaced gasket.

12/12/85 Leakage at top right plate.

01/05/86 All 4 inner bolts on side

"Plate are leaking air.

07/24/86 Tighten or replace fittings in

sense line.

Installed new gaskets on

cover.

Installed new cover plate

gasket.

Torqued bolts.

Tightened fittings.
114

Table D.1 (cont'd)

UTILITY NUCLEAR PLANT AIR' COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE

07/26/86

PROBLEM

Cooling water leak from head

gasket.

ACTION TAKEN

08/14/86 Air leaks around top of

compressor.

01/07/87 Leak at discharge cover plate.

06/17/87 Head gasket is leaking water.

09/20/87 Evaluate/repair/replace

cracked housing.

Tightened top cover bolts.

Replaced intake and discharge

valve, head gaskett cylinder

gasket,framehead oil cover

gasket and discharge cover

plate.

10/08/87 Oil has milky appearance.

12/23/87 Air leaks from top plate.

Replaced rings, valves?

gaskets, packing, bearings,

crankshaft and belts.

Replaced gaskets and torqued

bolts.

PROBLEM TYPE: Mechanical

08/05/82 Compressor is locked up; will

not run.

09/07/82 Low oil level.

09/22/82 Compressor tripped twice on

low oil level signal.

12/13/82 Low oil level.

12/18/82 Compressor started smoking and

appears to. have burned up.

07/11/84 Compressor not' pumping air. Reassembled crankshaft

assembly, set head clearance.

Packing seals and cover

plates.
115

1. Table D.1 (cont'd)

UTILITY NUCLEAR PLANT AIR COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

-DATE - _ PROBLEM ACTION TAKEN

09/21/85 Crankcase appears to be full Rebuilt compressor.

of water, which is leaking

from head down push rod and

into crankcase at push rod

seals.

07/14/86 Add oil to compressor.

10/08/87 Oil has milky appearance.

10/27/87 Worn oil stop plate.

Replaced rings, valves,

gaskets, packing, bearings,

crankshaft and belts.

Fabricated oil stop plate.

PROBLEM TYPE: Piston Rings

10/08/87 Oil has milky appearance.

..' - .

Replaced rings, valves

gaskets, packing, bearings,

crankshaft and belts.

PROBLEM TYPE: Seals

09/20/87 Oil level 1/4" below normal. Replaced faulty scraper rings

and added oil.

PROBLEM TYPE: Valves

05/09/82 Unloader valve stuck open.

06/20/83 Compressor continues to

overload BLR; not unloading.

09/20/87 Evaluate/repair/replace

cracked housing.

Replaced intake and discharge

valve, head gasket 3 cylinder

gasketframehead oil cover

gasket and discharge cover

plate.
116;

Table D.1 (cont'd)

UTILITY NUCLEAR PLANT AIR COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE PROBLEM

10/08/87 Oil has milky appearance.

ACTION TAKEN

Replaced rings, valves,

gaskets, packing, bearings,

crankshaft and belts.

AUXILIARY COMPRESSOR "BB"

PROBLEM TYPE: Belts

01/12/83 Inspect, tighten, or replace

drive belts as needed.

09/14/83 Replace belts thrown off; one

remained on.

10/30/84 Adjust or replace belts as 'k needed.

01/09/85 Adjust or replace belts as

needed.

PROBLEM TYPE: Controls

02/28/82 Safe stop switch not working.

12/22/82 Irregular compressor

operation; loads and unloads

constantly.

01/31/83 Compressor is coming on and

I going off.

04/27/83 Replace cooling water

solenoid; check crankcase for

water.

03/05/87 Compressor won't start in

"AUTO" oh low pressure.

01/24/88 Compressor trips on low oil

level during sustained run - level low or switch problem?

Cleaned relay, replaced a

screw in delay diaphragm, and

replaced Agastat relay.

Added oil and corrected

loosely connected lead.
117

Table D.1 (cont'd)

UTILIZY NUCLEAR PLANT AIR COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE PROBLEM

PROBLEM-TYPE: Heat Exchangers and Traps

02/22/85 Clean aftercooler tubes to

remove scale and any debris

that may be limiting water

flow.

PROBLEM TYPE: Leaks

01/03/81 Unloader is leaking air.

06/01/81 Air leak around head - blown

seal.

01/12/82 Unloader is leaking air.

03/10/83 Water leak at cooling water

inlet union.

03/11/83 Repair copper tubing leaks on

loading system.

03h3/83 Water in oil.

03/22/84 Possible blown head gasket.

07/12/84 Air leak at cover gasket.

03/07/85 Leaks around top and side

plates.

ACTION TAKEN

Removed heads, cleaned, and

reinstalled.

10/31/85 Air leak in seal between head

and main body.

10/31/85 3 of 4 boltsion inspection

cover plate are leaking air.

03/19/86 Repair to reduce leaks.

Replaced cover gasket.

Replaced gaskets. Installed

hold-down bars on lower

discharge valve cover plate.

Tightened bolts to stop leak.

Tightened bolts.

Torqued plate bolts to stop

leak.

Cl.
118

UTILITY NUCLEAR

Table D.1 (cont'd)

PLANT AIR COMPRESSOR 14AINTENANCE CALLS

(BY PROBLEM TYPE)

DATE PROBLEM ACTION TAKEN

PROBLEM TYPE: Mechanical

03/31/81 Compressor has broken shaft.

02/16/84 Oil level below normal.

05/25/84 Noisy crankshaft and

discolored oil.

Disassembled compressor and

rebuilt.

05/31/84 Repeated trips on low oil

level; add oil or fix limit

switch.

07/13/84 Add oil to crankcase.

07/25/84 Compressor makes loud knocking

noise when started and

running.

10/04/84 Compressor does not build

pressure. Air blows out

intake when running and when

first stopped. Keeps tripping

on overload.

01/17/85 Shaft appears to be uncoupled

or broken - pulley turns but

no shaft movement.

07/03/85 Compressor is making a bad

knocking sound when unloaded.

07/24/85 Compressor is making a bad

knocking sound.

06/15/86 Air leak around shaft.

09/22/87 Evaluate/repair/replace

cracked housing headframe near

inlet valve cover.

Added oil.

Removed head and adjusted

piston clearance.

Rebuilt compressor. Replaced

gasket studs and nuts.

Installed new crankshaft, new

valves, new piston, rings,

piston rod, connector rod, and

gaskets.

Replaced crankshaft and

connecting rod.

Replaced crankshaft and rod

assembly. Installed new

bearings.

Worn internals.

compressor.

Rebuilt

Replaced lower frame and

rebuilt compressor.
119

Table D.1 (cont'd)

UTILITY NUCLEAR PLANT AIR COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE

11/03/87

PROBLEM

Water coming from intake

filter when compressor is

unloaded. Compressor is also

knocking loudly.

ACTION TAKEN

Disassembled, inspected, and

reassembled compressor.

Rod locking washer came loose

and am nut backed off.

Readjusted piston rod - ran

again and same thing happened.

Installed lock washer.

05/02/88 Suspected leak at piston rod

seal.

PROBLEM TYPE: Piston Rings

01/17/85 Shaft appears to be uncoupled

or broken - pulley turns but

no shaft movement.

Installed new crankshaft, new

valves, new piston, rings,

piston rod, connector rod, and

gaskets.

PROBLEM TYPE: Seals

02/01/85

03/07/85

PROBLEM

Oil leak around piston shaft.

Leaking piston shaft seal.

Repacked piston shaft.

Replaced shaft seals.

TYPE: Valves

08/26/84 Intake blows air every other

stroke; repair damaged intake

valve.

01/17/85 Shaft appears to be uncoupled

or broken - pulley turns but

no shaft movement.

10/23/85 Compressor cycles; loads and

unloads continuously on 3-5

second cycle.

Replaced intake valve.

Installed new crankshaft, new

valves, new piston, rings,

piston rod, connector rod, and

gaskets.

Rebuilt intake unloader.
120

Table D.1 (cont'd)

UTILITY NUCLEAR PLANT AIR COMPRESSOR MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE PROBLEM ACTION TAKEN

11/20/85 Replace intake and discharge

valves.
121

i Table D.2

UTILITY NUCLEAR PLANT AIR DRYER MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE PROBLEM -

ACTION TAKEN

SERVICE/CONTROL DRYER 'A"

PROBLEM TYPE: Controls

08/30/87 Dryer will not purge at all. Replaced burned out timer

motor.

PROBLEM TYPE: Desiccant and Filters

05/18/84 Desiccant needs to be

replaced.

09/21/87 Remove dirty filters and

inspect prefilter and

afterfilter for clogging or

wear.

Replaced desiccant.

Disassembled and cleaned

moisture trap. Replaced

afterfilter elements.

PROBLEM TYPE: Valves

04/22/88 Dirty valve - air dryer

continuously blows down.

Replaced purge air valve and

2" galvanized union. Cleaned

muffler.

09/16/88 Change out desiccant.

Repair/replace O-FCV-32-45B.

Desiccant was good. Replaced

O-VLV-32-45B and cleaned

lines.

SERVICE/CONTROL DRYER "B"

PROBLEM TYPE: Desiccant and Filters

10/14/83 Replace desiccant.

09/21/87 Remove dirty filters and

inspect prefilter and

afterfilter for clogging or

wear.

Disassembled and cleaned

moisture trap. Replaced

afterfilter elements.
122

Table D.2 (cont'd)

UTILITY NUCLEAR PLANT AIR DRYER MAINTENANCE CALLS

(BY PROBLEM TYPE)

DATE PROBLEM

10/18/88 Change out desiccant; air

header delta P 25 psi.

ACTION TAKEN

Desiccant OK. Changed out

desiccant in sight glass.

PROBLEM TYPE: Valves

08/30/87 Dryer wilt not purge at all.

04/14/88 Dryer is not operating

correctly.

Replaced Tower 1 purge valve.

Disassembled 2" and 1" check

valves. Found clay-like

pebbles in l" valve, not

allowing valve to seat.

Cleaned and reassembled.

SERVICE/CONTROL DRYER "C"

PROBLEM TYPE: Desiccant and Filters

09/21/87 Remove dirty filters and

inspect prefilter and

afterfilter for clogging or

wear.

Disassembled and cleaned

moisture trap. Replaced

afterfilter elements.

AUXILIARY DRYER "BB"

PROBLEM TYPE: Desiccant and Filters

02/16/88 Desiccant needs replacement

due to high delta P - 6 psid,

limit is 5 psid.

Changed out desiccant.
123

NUREG/CR-5519

Volume 1

ORNL-6607/Vl

Dist. Category RV

Internal Distribution

1. D. A. Casada 18. C. A. Murphy

2-3. D. M. Eissenberg 19. C. E. Pugh

4. E. C. Fox 20. ORNL Patent Section

5. E. W. Hagen 21. Central Research Library

6. H. D. Haynes 22. Document Reference Section

7. J. E. Jones Jr. 23-24. Laboratory Records Department

8-17. J. C. Moyers 25. Laboratory Records (RC)

External Distribution

26. I. Debiassi, Tennessee Valley Authority, Sequoyah Nuclear

Plant, MA-2, P.O. Box 2000, Soddy Daisy, TN 37379

27. S. Denton, Air Components and Systems Ltd., 3121 Northwest Park

Drive, Knoxville, TN 3921

28. W. S. Farmer, U.S. Nuclear: Regulatory Commission, Office of

Nuclear Regulatory Research, Electrical and Mechanical

Engineering Branch, 5650 Nicholson Lane, Rockville, MD 20852

29. M. J. Jacobus, Sandia National Laboratories, P.O. Box 5800,

Division 6447, Albuquerque, NM 87815

30. A. B. Johnson, Battelle-PNL, MS P8-10, P.O. Box/999, Richland,

WA 99352

31. H. L. Magleby, Idaho National Engineering Labo/ratofy, MS 2406,

P.O. Box 1625, Idaho Falls, ID 83415

32. C. E. Sliter, Electric Power Research Institute, P.O. Box

10412, Palo Alto, CA 94303

33. J. H. Taylor, Brookhaven National Laboratory, Bldg. 130, Upton,

NY 11973

34. J. W. Tills, Institute for Nuclear Power Operations, 1100

Circle 75 Parkway, Atlanta, CA 30339-3064

35. M. Vagins, U.S. Nuclear Regulatory Commission, Office of

Nuclear Regulatory Research, Chief, Electrical and Mechanical

Engineering Branch, Division of Engineering, 5650 Nicholson

Lane, Rockville, MD 20852

36. J. P. Vora, U.S. Nuclear Regulatory Commission, Office of

Nuclear Regulatory Research, Electrical and Mechanical

Engineering Branch, 5650 Nicholson Lane, Rockville, MD 20852

37. Office of Assistant Manager for Energy Research and Development, Department of Energy, Oak Ridge Operations Office, Oak

Ridge, TN 37831

38-39. Office of Scientific and Technical Information, P.O. -Box 62,

Oak Ridge, TN 37831

40-369. Civen distribution as shown in RC category RV (10-NTIS)
I

NRC SOFAS' 335 US. NUCLEAR REGULATORY COMMISSION 1. REPORT NUMBER

(2 91 , jAssnod b bC. Add Vol.. Supp, vi... NCI IIC2. and Adadnvm nombers. If any.?

3201.32C2 BIBLIOGRAPHIC DATA SHEET NUREG/CR-5519, Vol 1

tS instrucrons on the revrse) ORNL-6607/Vl

2. TITLE AND SUBTITLE

Aging of Control and Service Air Compressors' d Dryers Used

in Nuclear Power Plants 3. DATE REPORT PUBLISHED

MON" | FR

July 1990

4. FIN OR GRANT NUMBER

B0828

S. AUTHORISI 6. TYPE OF REPORT

J. C. Moyers Technical

7. PERIOD COVER ED II.chlsi.' DIr

8. PE RFORMI NG ORGANIZATION -NAME AND ADDRESS (It NRC.O roie Oivision. Office of teion, U.S. 1N.Regju1Aa1&ror Commasson. Ad MAi;thl adress. itconrbcoorpror..

name bon mding adrers.I

Dak Ridge National Laboratory

P. 0. Box 2008

Oak Ridge, TN 37831

9. SPONSORING ORGANIZATION - NAME AND ADDRESS ilo NRC. type 'aSan *how ifcontrscror.proid NRCOision. Office or Segion. U. moA, wRgwatorn Commmion.

enifwuallin addr.5s.1

Division of Engineering

ffice of Nuclear Regulatory Research

U. S. Nuclear Regulatory Commission

Washington, DC 20555

10. SUPPLEMENTARY NOTES

11. ABSTRACT t200 oads , IvJ

This report was produced under the Detection of Defects and Degradation Monitoring of

Nuclear Plant Safety Equipment element of the Nuclear Plant Aging Research Program.

This element includes the identification of practical and cost-effective methods for

detecting, monitoring, and assessing the severity of time-dependent degradation (aging)

of control and service air compressors and dryers in nuclear power plants. These

methods are to provide capabilities for establishing degradation trends prior to failure

and developing guidance for effective maintenance.

The topics of this Phase I assessment report are failure modes and causes

resulting from aging, manufacturer-recommended maintenance and surveillance practices,

and measurable parameters (including functional indicators) for use in assessing operational readiness, establishing degradation trends, and detecting incipient failure. The

results presented are based on information derived from operating experience records,

manufacturer-supplied information, and input from plant operators.

For each failure mode, failure causes are listed by sub-component, and parameters

potentially useful for detecting degradation that could lead to failure are identified.

12. KEY WORDS!DESCR PTORS L ita *olds or Nses thar nil asist ,eseAchef 5i locang the repon.i 13. AVAILABI LIT Y STATE hENT

compressed air nuclear power plants Unlimited

aging NPR14. SECURITY CLASSIFICATION

failures operating experience ,ifsis Pgt

reliability Unclassified

maintenance (Ths Reprn

compressors Unclassified

dryers 15. NUMBER OF PAGES

16. PRICE

NIRC FORM 33b 1249'
UNITED STATES

NUCLEAR REGULATORY COMMISSION

WASHINGTON, D.C. 20555

OFFICIAL BUSINESS

PENALTY FOR PRIVATE USE, $300

ECIAL FOURTHU-CLSS RATE

POSTAGE a FEES PAID

PRINoCC

PERMIT No. G-6l

i