An Aging Failure Survey

of Light Water Reactor

Safety Systems and Components

NUREG/CR-4747

EGG-2473

Volume 1

July 1987

Babette M. Meale

David G. Satterwhite

ri EORGQdaho

Work performed under

DOE Contract No. DE-AC07-761D01570

for the U. S. Nuclear

Regulatory Commission

F 0 R M A L R E P O R T

>~~~~~~~~~~~~~~~~~ I

_>E ~~~~~~~~~~~I'

Idaho National

Engineering Laboratory

Managed by the U. S. Department of Energy
Available from

Superintendent of Documents

U.S. Government Printing Office

Post Office Box 37082

Washington, D.C. 20013-7982

and

National Technical Information Service

Springfield, VA 22161

NOTICE

This report was prepared as an account of work sponsored by an agency of

the United States Government. Neither the United Sates Government nor any

agency thereof, nor any of their employees, makes any warranty, expressed

or implied, or assumes any legal liability or responsibility for any third party's

use, or the results of such use, of any information, apparatus, product or process disclosed in this report, or represents that its use by such third party would

not infringe privately owned rights.
NUREGICR-4747

EGG-2473

Volume 1

Distribution Category: RG, RM

AN AGING FAILURE SURVEY

OF LIGHT WATER REACTOR

SAFETY SYSTEMS AND COMPONENTS

Babette M. Meale

David G. Satterwhite

Published July 1987

EGEtG Idaho, Inc.

Idaho Falls, Idaho 83415

Prepared for the

Division of Engineering Safety

Office of Nuclear Regulatory Research

U.S. Nuclear Regulatory Commission

Washington, D.C. 20555

Under DOE Contract No. DE-AC07-761D01570

FIN No. A6389
ABSTRACT

This report describes the methods, analyses, results, and conclusions of two different aging studies. The first analysis consists of a survey of light water reactor component failures associated with selected safety and support systems. Tables are

presented, indicating the systems and the components within those systems most

affected by aging. Also provided are engineering insights drawn from the data. The

second analysis consists of identifying and categorizing the reported failure causes of

component failures. The systems used in the failure-cause analysis were service water

systems and Class IE electrical power distribution systems for Babcock & Wilcox

Company pressurized water reactors and service water systems for boiling water

reactors.

FIN No. A6389-Aging Systems Interaction Study:

Component Residual Lifetime Evaluation and

Feasibility Relicensing

.
EXECUTIVE SUMMARY

This report presents the methods, analyses,

results, and conclusions of an aging survey of light

water reactor safety system component failures and

a detailed aging-related failure-cause analysis of

component failure reports. Both studies were performed for the U.S. Nuclear Regulatory Commission (NRC) as a part of the Nuclear Plant Aging

Research Program. This report is the first volume

of a two-volume set addressing the impact of component aging on selected nuclear power plant safety

and support systems. A third document will

address the risk importance of time-dependent

aging-related failures using the failure cause data

reported in Volumes I and 2.

The purpose of the analyses presented here is to

identify which safety and support systems and their

associated components have been affected by aging

and, for selected systems, to identify aging-related

failures at the reportable cause or mechanism level.

The following definition of aging is used in the

analyses presented in this report:

"Aging" is the degradation of a component

resulting in the loss of function or reduced

performance caused by some time-dependent

agent or mechanism. The agent or mechanism can be cyclic, e.g., caused by repeated

demand, or continuously acting, e.g., caused

by the operational environment. The change

in the component failure probability resulting

from the degradation will be monotonically

increasing with the time of exposure to the

agent or mechanism unless the component is

refurbished, repaired, or replaced.

The nuclear power plant operational data

selected for aging-related failure analysis were from

the Nuclear Plant Reliability Data System

(NPRDS), a data base of the Institute of Nuclear

Power Operations. The NPRDS is considered the

best currently accessible data base on which to perform the present work scope of the aging-related

data collection and analysis. However, the data

source does have significant limitations (detailed in

Section 3.2) that should be considered when interpreting or applying the results. The plant-specific

NPRDS data are proprietary. Therefore, the data

presented in this report have been made generic to

enable wider distribution of the results and to

ensure that those results cannot be traced to specific plants or manufacturers.

The analyses documented in this report examine

the NPRDS data using two unique procedures. An

aging survey analysis was performed on the failure

reports for nine complete systems, including both

pressurized water and boiling water reactors. The

purpose of this survey was to identify which systems and which associated components were being

most affected by aging phenomena. It is a rather

gross analysis but does provide relative magnitudes

of aging effects between systems and components.

The results of the aging survey will help define

future in-depth engineering studies of selected systems and components. The second analysis consisted of a failure-cause determination to identify

the aging mechanisms, to the level of resolution

available in the failure reports, that caused component failures in two safety and support systems. To

determine true root causes of failures for the failed

components is beyond the scope of this study. That

would require a detailed in-depth engineering evaluation to be performed on the components. Guidelines developed by the Root Causes of Component

Failures Programa were used in identifying the failure mechanisms. An aging classification procedure

was developed to aid the analyst in distinguishing

aging-related from non-aging (random) failures.

The results of the failure cause study will be used in

systems-level aging evaluations using probabilistic

risk assessment (PRA) techniques.

Aging Survey Analysis

In the aging survey, failure information for

aging-related and non-aging failures was obtained

for nine different light water reactor safety and support systems. The information was used to create a

computerized data base which was analyzed to

identify time-dependent failure contributions of

system/component combinations. The failures

were grouped into five broad failure categories.

Mechanisms of failure were not determined during

this analysis; however, several analyses were performed using the failure-category data. Selected

groupings of the data were examined to identify

systems and components that are susceptible to

aging failures. Also, a rudimentary uncertainty

a. D. G. Satterwhite, L. C. Cadwallader, W. E. Vesely,

B. M. Meale, Root Causes of Component Failures Program:

Methods and Applications, NUREG/CR-4616, EGG-2455,

December 1986.

iii
analysis was performed to provide an indication of

the confidence to be placed in the data analysis

results.

The analyses of the data provided several insights

into the effect of aging failures. For the systems

studied, the failure categories of "aging" and

"other" contained the majority of the failures. The

contribution to failures in the "human-related"

category was very minimal. Approximately )1.of

the failures reported were attributed to aging, and

50°7 of the failures reported were categorized as

"other." The "other" category consists of failures

for which the cause was not determined or could

not be assigned to another category. The size of the

"other" category is indicative of both the difficulty

in determining the cause of failure for certain components and the practice of replacing a component

or piece part without establishing the reason for

failure; therefore, a reasonable but unknown fraction of the failures in the "other" category is also

probably due to aging mechanisms. While it is recognized that the aging category could also contain

an unknown number of misclassified failures, comparison to the failure-cause study indicates that this

misclassification is probably minimized.

Results of the aging survey indicate that, in general, a system's operational mode is a factor influencing aging-related component failures. The

normally operating fluid systems, such as the service water systems, main feedwater systems, and

component cooling water systems, exhibited the

highest aging failure fractions, with pumps and

valves being the components most affected. However, there are significant exceptions to this observation concerning a system's operational mode.

Components in some standby systems also display

high aging fractions, e.g., pumps in the standby

liquid control systems and valves and pumps in the

diesel subsystems of the Class IE electrical power

distribution systems. A limited analysis of these

systems indicates that the standby components are

adversely affected by their operational environment.

Aggregation and evaluation of the data at the

system level to determine system effects indicated

that only a small fraction of the failures caused

"loss of system function." There was no dominant

system effect category.

Examination of the component aging-fraction

data indicates that the system/component combinations impacted by aging phenomena are identifiable. The system/component combinations most

affected by aging are (a) valves and pumps in normally operating systems, (b) Class IE diesel subsystem components, (c) heat exchangers in the

main feedwater system, and (d) standby liquid

control system pumps.

Reported Failure Cause Analysis

The failure-cause analysis of component failures

used a cause categorization scheme to identify and

characterize the reported cause-of-failure information for aging-related and non-aging failures for

selected light water reactor systems. The systems

chosen for this analysis were service water systems

and Class lE electrical power distribution systems.

The cause identification information provides

insights into the effects of aging versus non-aging

failures on system performance. Other light water

reactor safety and support systems will be studied

in the future.

Eight-hundred-and-fifty component failures

were evaluated. Results of the analysis indicate that

two components in the service water system and

one component in the Class IE electrical power

distribution system dominated the failure contributions. Motor-operated valves and motor-driven

pumps contributed the largest number of failures

within the service water system. These components

exhibited relatively high aging-related failure fractions (fraction of total component failures attributable to aging). Aging-related failure fractions

calculated in percentages for motor-operated valves

were a lower-bound of 39% and an upper-bound of

84°0%. Fractions for motor-driven pumps are 77%

and 84°7, respectively. The dominant aging failure

cause for these two components was "wear."

Within the service water system, check valves (87To

to 90%) and strainers (81%o to 86%o) exhibited the

highest aging fractions with "wear" and "corrosion" being the dominant mechanism reported.

The diesel generators dominated the Class IE electrical power distribution system failures with a

lower-bound aging-related percentage of 49% and

an upper-bound of 66%. Components within the

Class IE electrical power distribution systems

exhibiting the highest aging fraction were battery

chargers (51 °7o to 97%). The dominant aging cause

for the Class IE electrical power distribution systems was "wear."

iv
FOREWORD

This report is the first volume of a two-volume set addressing the impact of component aging on selected nuclear power plant safety and support systems. A future

document using the results presented in Volumes I and 2 will address the risk importance of time-dependent, aging-related failures using reported failure-cause data. The

work was performed for the U.S. Nuclear Regulatory Commission as part of the

Nuclear Plant Aging Research Program. Data selected for these analyses were from

the Nuclear Plant Reliability Data System, a data base of the Institute of Nuclear

Power Operations.

v
ACKNOWLEDGMENTS

The authors wish to express their sincere appreciation to the following persons for

their assistance in the aging survey: J. P. Vora (NRC), for his program guidance;

B. Marcus (NRC), for expediting the acquisition and transmittal of the Nuclear Plant

Reliability Data System data; M. R. Nelson, for the computer programming to create

the data base; B. J. Quintana, for executing the computer program and assisting in

assimilating the information produced by the computer sort; Dr. C. L. Atwood and

C. L. Hertzler, for performing the uncertainty study and assisting in interpreting the

results of the uncertainty study; and E. B. Bounds, for her expertise in word processing and table formatting.

The authors also wish to thank those listed below for their assistance in the reported

failure cause identification analysis: P. M. McGuire, for her help in the cause identification and research into existing failure modes; J. L. Plum, for his help in the cause

identification; P. T. Jacobs, for his helpful comments and assistance during discussions of the aging task; S. Z. Bruske, for her assistance and guidance regarding the

cause analysis methodology; L. C. Cadwallader, for keeping an excellent and current

failure mode library; and J. L. Edson, for his assistance in developing the component

boundaries for the measurement system.

vi
CONTENTS

ABSTRACT ..................................... ................. ii

EXECUTIVE SUMMARY ..................................................... iii

FOREWORD ..................................... v

ACKNOWLEDGMENTS ..................................................... vi

ACRONYMS ........................................................................ xi

1. INTRODUCTION ........................... I..........................

2. DEFINITIONS ............. . 3

3. METHODOLOGY ...................................................... 5

3.1 Aging Definition and Classification ............................................ 5

3.2 Failure Event Data Source .................................................... 5

3.3 Aging Survey Analysis ...................................................... 6

3.4 Reported Failure Cause Analysis and Aging Classification ........................ 7

4. RESULTS .. 11

4.1 Aging Survey Analysis .11

4.2 Reported Failure Cause Analysis .19

5. CONCLUSIONS................................................................ 23

5.1 Aging Survey Analysis .23

5.2 Reported Failure Cause Analysis .23

6. REFERENCES ................................................................. 24

APPENDIX A-ACRONYMS AND CODES FOR THE AGING FAILURE SURVEY ......... A-I

APPENDIX B-REPORTED FAILURE CAUSE IDENTIFICATION INFORMATION ....... B-I

APPENDIX C-COMPONENT BOUNDARIES FOR THE FAILURE CAUSE

IDENTIFICATION STUDY ............................................ C-i

APPENDIX D-FAILURE MODE CODES AND DEFINITIONS .......................... D-I

APPENDIX E-AGING FAILURE SURVEY INFORMATION ............................ E-1

APPENDIX F-REPORTED FAILURE CAUSE DATA SUMMARIES ..... ................. F-I

vii
FIGURES

I. Relationship of the NPRDS cause categories and the aging survey failure categories ...... 8

2. Relationship of the failure category fractions by system .............................. 13

3. Relationship of the system effect fractions by system ................................. 13

4. Relationship of the component aging fractions by system ............................. 14

5. Relationship of the instrumentation component aging fractions by system ..... ......... 14

B-i. Failure cause coding form ................ ....................................... B-4

TABLES

1. Example of the root cause categorization scheme (full depth) ......................... 9

2. Example of detailed aging survey tables ............................................ 12

3. Uncertainty study: no statistical system dependency related to aging ..... .............. 15

4. Uncertainty study: statistical system dependency related to aging ..... ................. 16

5. System/component combination time-dependent aging fractions ...................... 17

6. Table of SWS and Class IE Component failures and aging fractions as determined

by the reported causes of failure study ............................................. 19

7. Reported failure cause identification summary ...................................... 21

A-I. Failure category assignments for NPRDS codes ..................................... A-3

A-2. NPRDS component acronyms ............. ...................................... A-4

A-3. NPRDS system effect descriptions ........... ..................................... A-5

B-l. Cross-reference fields between the NPRDS records and the failure cause coding form ..... B-6

B-2. Failure cause categorization and aging classification scheme .......................... B-7

C-l. Supports and snubbers piece parts .C-7

D-1. Failure mode codes .D-3

D-2. Failure mode descriptions .D-5

E-1. Class IE electrical power distribution system .E-4

E-2. Class IE electrical power distribution system totals and fractions .E-5

E-3. Class IE electrical power distribution system component failure category fractions .E-6

viii
E4. Auxiliary feedwater system ...................................................... E-8

E-5. Auxiliary feedwater system totals and fractions ..................................... E-9

E-6. Auxiliary feedwater system component failure category fractions ...................... E-10

E-7. Component cooling water system ................................................. E-1 1

E-8. Component cooling water system totals and fractions ................................ E-12

E-9. Component cooling water system component failure category fractions ..... ............ E-13

E-10. High-pressure injection system ................................................... E-14

E-l 1. High-pressure injection system totals and fractions .................................. E-15

E-12. High-pressure injection system component failure category fractions ..... .............. E-16

E-13. Main feedwater system ............... ........................................... E-17

E-14. Main feedwater system totals and fractions ......................................... E-18

E-15. Main feedwater system component failure category fractions .......................... E-19

E-16. Reactor protection trip system .................................................... E-20

E-17. Reactor protection trip system totals and fractions .................................. E-21

E-18. Reactor protection trip system component failure category fractions ..... .............. E-22

E-19. Residual heat removal system .................................................... E-23

E-20. Residual heat removal system totals and fractions ................................... E-24

E-21. Residual heat removal system component failure category fractions ..... ............... E-25

E-22. Service water system . ........................................................... E-26

E-23. Service water system totals and fractions ........................................... E-27

E-24. Service water system component failure category fractions ............................ E-28

E-25. Standby liquid control system .................................................... E-29

E-26. Standby liquid control system totals and fractions ................................... E-30

E-27. Standby liquid control system component failure category fractions ..... ............... E-31

F-I. Summary of data analyzed during the failure cause identification analysis ..... ......... F-4

F-2. Summary of components having less than 5 counts each ............................. F-6

F-3. Failure cause tallies, failure cause fractions, and aging fractions for SWS check valves .... F-8

ix
F-4. Failure cause tallies, failure cause fractions, and aging fractions for

SWS hand control valves . ........................................................ F-10

F-5. Failure cause tallies, failure cause fractions, and aging fractions for

SWS motor-operated valves ............... ....................................... F-13

F-6. Failure cause tallies, failure cause fractions, and aging fractions for SWS

pneumatic-operated valves ................ ....................................... F- 17

F-7. Failure cause tallies, failure cause fractions, and aging fractions for SWS

motor-driven pumps ............................................................. F-20

F-8. Failure cause tallies, failure cause fractions, and aging fractions for SWS strainers .... .... F-23

F-9. Failure cause tallies, failure cause fractions, and aging fractions for

SWS circuit breakers, AC . ........................................................ F-24

F-10. Failure cause tallies, failure cause fractions, and aging fractions for

SWS flow indicators ............................................................. F-25

F-il. Failure cause tallies, failure cause fractions, and aging fractions for

SWS flow switches ............................................................. F-26

F-12. Failure cause tallies, failure cause fractions and aging fractions for

SWS pressure indicators . ........................................................ F-27

F-13. Failure cause tallies, failure cause fractions, and aging fractions for

UPS circuit breakers, AC . ........................................................ F-28

F-14. Failure cause tallies, failure cause fractions, and aging fractions for UPS inverters .F-29

F-15. Failure cause tallies, failure cause fractions, and aging fractions for DC power batteries ... F-30

F-16. Failure cause tallies, failure cause fractions, and aging fractions for DC power battery

charging unit .F-31

F-17. Failure cause tallies, failure cause fractions, and aging fractions for emergency power

circuit breakers .F-32

F-18. Failure cause tallies, failure cause fractions, and aging fractions for emergency power

diesel generator .F-33

F-19. Failure cause tallies for system effect .F-37

F-20. Summary of records in which the failure cause was unclassifiable .F-46

x
ACRONYMS

AFW auxiliary feedwater system

B&W Babcock & Wilcox

CCW component cooling water system

GE General Electric Company

HPIS high-pressure injection system

INEL Idaho National Engineering Laboratory

INPO Institute of Nuclear Power Operations

LER licensee event report

LWR light water reactor

MFW main feedwater system

NPAR Nuclear Plant Aging Research

NPRDS Nuclear Plant Reliability Data System

NRC U.S. Nuclear Regulatory Commission

NSSS nuclear steam system supplier

PRA probabilistic risk assessment

RHR residual heat removal system

RPS reactor protection trip system

SBL standby liquid control system

SWS service water system

IE Class IE electrical power distribution system

xi
AN AGING FAILURE SURVEY

OF LIGHT WATER REACTOR

SAFETY SYSTEMS AND COMPONENTS

1. INTRODUCTION

Problems caused by time- or cyclic-dependent

degradation (aging) mechanisms, such as wear, corrosion, and fatigue, have occurred at some U.S.

nuclear power plant reactors. These problems have

raised questions about the age-dependent degradation of safety equipment at the plants. Many of

these issues have been, and are being, addressed by

the nuclear industry through research, improved

designs, standards development, and, especially,

improved operational and maintenance practices.

Nevertheless, aging and degradation of plant safety

systems and components will continue, and currently unrecognized degradation effects are likely as

the U.S. light water reactor (LWR) population ages.

Collection and evaluation of operating experience

data are necessary to study the effects of aging and

degradation on the safety of operating nuclear

power plants during their normal design life and any

extended life.

Therefore, an important part of the U.S. Nuclear

Regulatory Commission (NRC) research effort is the

Nuclear Plant Aging Research (NPAR) Programl

which is being conducted at several national laboratories, including the Idaho National Engineering

Laboratory (INEL). One of the NPAR Program

tasks at INEL is to evaluate the extent to which aging

has affected the performance of light water reactor

safety and support systems. This study uses data

from Licensee Event Reports (LER) and the Nuclear

Plant Reliability Data System (NPRDS) of the Institute of Nuclear Power Operations (INPO). Specific

objectives include: (a) identifying which light

water reactor safety or support systems and components have been significantly affected by aging,

(b) identifying specific aging failure causes for a few

selected systems and components, (c) calculating

aging contributions to system and component

unavailabilities, and (d) developing quantitative

relationships between aging failure data and risk.

This report is the first volume of a two-volume set

addressing the impact of component aging on

selected nuclear power plant safety and support systems. A future document using the results presented

in Volumes I and 2 will address the risk importance

of time-dependent, aging-related failures using

reported failure-cause data. The specific objectives

of the analyses reported herein center around the

first and second program objectives.

The analyses documented in this report address

these two objectives using two unique procedures to

analyze NPRDS data. The first, an aging survey

analysis, was performed on the failure reports for

nine light water reactor safety, support, and power

conversion systems, including both pressurized

water and boiling water reactors. The purpose of

this survey was to identify which systems and associated components were being most affected by aging

phenomena. It is a rather gross analysis but provides

relative magnitudes of aging effects between systems

and components. The second analysis consisted of a

failure cause determination to identify the aging

mechanisms that caused component failures associated with the service water and Class IE power distribution systems. The depth of this analysis was

limited to the level of resolution available in the failure reports. To determine true root causes of failures

for the failed components is beyond the scope of this

study. Such a determination would require a detailed

in-depth engineering evaluation to be performed on

the components. Guidelines developed by the Root

Causes of Component Failures Program2 were used

in identifying the failure mechanisms. An aging classification procedure was developed to aid the analyst

in distinguishing aging-related from non-aging (random) failures.

The failure-cause information is useful in the evaluation of the influence of aging on plant risk using

probabilistic risk assessment (PRA) techniques. In

this application, the absolute magnitude of the aging

effects is not essential. Relative impacts are useful

for the modification of the PRA failure rate data.

In the aging survey, NPRDS failure data were

compiled for pressurized water reactor and boiling

water reactor systems and their major subsystems.

The vendors represented in this survey were

Westinghouse Electric Corporation (Westinghouse),

Babcock & Wilcox Company (B&W), and General

Electric Company (GE). It is recognized that several

I
of these systems are designed by the architect/

engineering firm and are not vendor specific. However, the NPRDS is structured to supply system

information by reactor vendor only. A breakdown of

systems surveyed is presented below:

* Class IE electrical power distribution systems (IE)-Westinghouse, B&W, GE;

* Auxiliary feedwater systems (AFW)-

Westinghouse, B&W;

* Component cooling water systems

(CCW)-B&W, GE;

* High-pressure injection systems (HPIS)-

Westinghouse, B&W;

* Main feedwater systems (MFW)-

B&W, GE;

* Reactor protection trip systems (RPS)-

Westinghouse, GE;

* Residual heat removal systems (RHR)-

GE;

Class IE electrical power distribution systems.

Reported cause-of-failure information was

obtained for the systems using the techniques developed in the NRC-sponsored Root Causes of Component Failures Program. 2 The cause

identification provides insights into the effects of

aging failures on system performance.

The service water systems and Class IE electrical power distribution systems were selected for the

initial aging-cause study for the following reasons:

* Probabilistic risk assessments indicate that

support systems (those supplying power or

cooling to the front-line preventive or mitigative systems) tend to dominate risk in

many plants.

* Corresponding systems exist in all nuclear

plants.

* Significant amounts of data have been

gathered on failures in these systems.

Future aging-cause analyses will include investigating and evaluating the impact of aging on systems

such as the high-pressure injection and auxiliary

feedwater systems.

Other work related to the system studies

described in this report has involved investigating

aging of components within the systems. Major

components included in those studies are motoroperated valves,3 electric motors,4 containment

purge valves,5 and diesel generators. 6 While those

studies provide very specific information related to

the given components, they do not address the systems in which the components reside. An additional aging study7 provides insight into

aging-related failures and system effects of failures

in reactor protection systems. The information for

this study was obtained both from the available

failure event data (NPRDS, Nuclear Power Experience, Inc., and LERs) and utility records. Of the

two, the utility records yielded significantly more

detailed information relating to aging failures.

Section 2 of this report discusses the definitions

of the terms used in the two analyses. Section 3

defines "aging" and describes the methodology.

Section 4 presents the results of the aging survey

and failure cause identification analysis. The conclusions are discussed in Section 5.

* Service water systems

Westinghouse, B&W, GE;

(SWS)-

* Standby liquid control systems (SBL)-

GE.

The information contained in the survey data is

specific to the nuclear steam system supplier, system, and component. The NPRDS component failure records were utilized to create a data base. This

data base was used to classify the NPRDS causecategory/cause-code combinations and assign

them to one of five major failure categories (see

Section 2). There was no examination of the

NPRDS failure records during this study. The inservice age of the component and the system effect

associated with the individual failures also were

evaluated.

The purpose of the failure-cause analysis

described in this report was to identify agingrelated failures at the reported failure cause level for

(a) boiling water reactor service water systems,

(b) B&W service water systems, and (c) B&W

2
2. DEFINITIONS

Definitions of the parameters used in the analyses are presented in this section. The definition of

aging as used in this report is presented in the next

section.

* Age-The intent of the aging survey was to

produce a time-dependent failure data

base for various component failures.

Therefore, for the current usage, the age of

the component in years at the time of the

failure was calculated from the in-service

date recorded in the NPRDS component

engineering record. The data were placed

into the following four age divisions:

0 to 4.9, 5 to 9.9, 10 to 14.9, and 15 to

20 years. No attempt was made to identify

how many times a given component failed.

The time-dependent data would reflect

replacement but not repair.

* Cause Categories-The cause categories

refer to the nine failure categories used by

NPRDS to classify a failure; e.g., design/

engineering, incorrect procedure, and

wearout. Appendix A (Table A-1) contains additional information concerning

this categorization.

* Cause Codes-The cause codes refer to the

codes used by NPRDS to identify the cause

of, or factors contributing to, the failure;

e.g., normal/abnormal wear, dirt,

mechanical damage/binding, and loose

parts.

* Components-The component designations in the NPRDS records are generic

names, sometimes referring to more than

one specific component. The failure category data are presented using these designations. Appendix A (Table A-2) defines

the NPRDS component acronyms.

* Engineering Parameters-Engineering

parameters indicate a variety of engineering information regarding the component.

This information includes type, application, ratings, construction materials, and

engineering values (such as temperature,

revolutions per minute, and horsepower)

with their corresponding units.

* Failure-A reduced functional efficiency

or effectiveness of the component of interest or the loss of ability of the component

to perform its intended function.

* Failure Categories-The failure categories

are broad generic categories used to classify the specific failure information. These

categories are defined as follows:

1. Aging (A)-Failures that are the consequence of expected, time-dependent

wear or degradation.

2. Design and Installation (D)-Includes

failures attributable to (a) inadequate

design of the responsible component

or system, (b) inadequate assembly or

initial quality of the responsible component or system, and (c) improper

installation of equipment.

3. Human Related (H)-Includes failures

attributable to incorrect procedures

that were followed correctly and to

failures caused or aggravated by personnel errors, including failure to follow procedures correctly.

4. Other/Unknown (0)-Includes failures attributable to failure or misoperation of another component or

system and to failures in which the

cause cannot be assigned to any of the

other categories.

5. Testing and Maintenance (T)-Failures

resulting from improper maintenance,

lack of maintenance, or personnel

error that occur during maintenance

or testing activities performed on the

responsible component or system.

* Failure Mode-The failure mode of a component is used in PRA analyses to refer to

an action that a component fails to perform. For example, a valve that will not

open when required is categorized in the

"fails to open" failure mode.

3
* Family Significance Level-If no components have significant between-system differences, one can expect 5% of the

components to show significance.

* Reported Failure Cause-An underlying or

initiating event or condition that produces

the failure of a component. This cause is

identifiable only to the level of detail

present in the event report.

* Significance Level-The probability that

test-indicated differences in aging effects

exist, when in fact there are no differences

for the given component between systems.

* System-Systems are defined in the aging

survey in the same manner as in the

NPRDS. There is some concern that the

utility definitions of systems differ somewhat from those used in the NPRDS.

However, this is not considered significant,

due to the relative nature of the data

obtained in these analyses. Systems are

defined in the failure-cause analysis in the

manner developed for use in the Root

Causes of Component Failure Program. 2

* System Effect-The system effect code

identifies the effect on the system caused

by the component failure. The codes were

taken directly from the NPRDS failure

records. The NPRDS has five system effect

categories. Appendix A (Table A-3) lists

the system effect codes and their corresponding descriptions.

4
3. METHODOLOGY

This section describes the methodology used in

the aging survey and the failure-cause analyses.

"Aging" is defined and its identification through a

classification procedure is discussed. The acceptability of the NPRDS for these types of analyses is also

discussed.

3.1 Aging Definition and

Classification

The definition of aging as used in the analysis presented in this report is:

"Aging" is the degradation of a component

resulting in the loss of function or reduced performance caused by a time-dependent agent or

mechanism. The agent or mechanism can be

cyclic, e.g., caused by repeated demand, or

continuously acting, e.g. caused by the operational environment. The change in the component failure probability resulting from the

degradation will be monotonically increasing

with the time of exposure to the agent or mechanism unless the component is refurbished,

repaired, or replaced.

Different types of aging agents or mechanisms

affect a component's performance during its operational life. Environmental effects, such as normal

wear of component parts, erosion, corrosion, cyclic

fatigue, etc., tend to affect the component in a continuous fashion with rather low aging rates. Other

types of aging stem from activities affecting the

component through a random event. An example of

the latter type is a random maintenance error which

causes the component to experience significantly

accelerated aging through a mechanism, such as

binding, resulting in wear. Random maintenance

errors will usually not be identified in a failure

report. There are other cases where a mechanism

identified as causing a failure could be considered

aging or random, depending upon the circumstances

under which the failure occurred. It is difficult to

distinguish aging-related failures from random failures solely on the basis of a failure description or

reported failure causes. Therefore, the practical

application of this definition leads to a certain

amount of uncertainty. Engineering evaluations of

the failed components and knowledge of the component maintenance histories are sometimes necessary

to accurately identify aging-related failures.

The analyses of component failures presented in

this report attempt to identify aging-related failures

through two different techniques. The aging survey

analysis uses computer sorting techniques to classify

the aging-related failures. This analysis relies on the

failure category codes assigned by the utility personnel when reporting the failure. The failure-cause

analysis attempts a more detailed and accurate determination of aging classification by physical examination of the failure report descriptions. The

aging-related failures were identified on the basis of

a classification procedure developed for the analysis.

These techniques are described in Section 3.4.

3.2 Failure Event Data Source

Licensee event reports were considered as a data

source but were rejected due to the nature of the data

collection system. The LER system acts as a reporting agent to the NRC and is concerned with the failure effects on systems and safety functions. As such,

LERs do not generally go into detail about specific

component failure mechanisms, causes, or required

repair actions. Additionally, the current LER guidelines do not require the reporting of certain single

failures of safety-related equipment. Since most

aging-related failures are single failures, this current

reporting requirement further reduces the utility of

the LER system for identifying aging-related failures.

Specific plant data are the most desirable because

of the availability of maintenance histories associated with the failed components. An additional feature of plant-specific data is the ability to identify

plant-environmental and human contributors to

aging-related failures. These are essentially averaged

out when analyses are performed using the generic

data bases, such as the NPRDS and LER systems.

However, individual plants have relatively small failure populations, and access to the plant data records

is very limited. Gaining access to specific plant

records and the resultant collection and analysis

process was beyond the scope of the current analysis.

The component-failure data selected for analysis

were obtained from the NPRDS. NPRDS is a

component-failure data system owned by INPO and

generated on a voluntary basis by the INPO member

utilities. The data for each failure are sent to INPO

for processing and input into the computerized data

5
base. INPO distributes these data to other member

organizations and to NRC upon request. The plantspecific NPRDS data are proprietary. Therefore, the

data presented in this report have been made generic

so events cannot be traced to specific plants or manufacturers.

The NPRDS data source has several strengths and

limitations that reflect on the quality of the data and

its applicability to certain uses and interpretations.

Some strengths are:

* The NPRDS is a large, computerized

nuclear power plant component failure data

base containing multiple entries for all the

safety-significant systems and components.

Many utilities contribute to the data base.

* Many of the equipment failures reported to

NPRDS are not reportable in LERs.

* Component engineering data are supplied

with the failure records. These data supply

items such as capacities or ratings and

equipment types. The in-service data of the

component are also provided in the engineering data.

* The component failure records provide a

categorization of the failure by the utility

personnel and a failure description. Event

dates, discovery methods, plant conditions,

and corrective actions are also provided.

* The data base contains sufficient information to allow a reasonable determination of

the relative number of failures attributable

to various mechanisms. Only 14% of the

850 NPRDS records examined for the

failure-cause analysis were unclassifiable

into one of the cause or effect codes.

Some of the limitations are:

* Not all utilities report to the NPRDS, but

the number and quality of reporting has

been increasing.

* Incipient failures are not reportable under

NPRDS reporting requirements.

* Complete maintenance histories of failed

components are not available, and the

effects of test and maintenance activities on

aging-related failures are masked.

^ The analyses results presented in this

report, using the wide spectrum of NPRDS

data, represent an average. Therefore,

plant-specific effects of maintenance or

environment are masked.

* Many failure reports in the data base do not

contain a true failure date but rather a discovery date. This is particularly true for

reports concerned with mechanical or electrical set point drift where an entire system

was checked at one time and all those found

out of specification were reported. While

these failures represent aging phenomena,

establishing either an exposure time or degradation versus time is impossible.

* For some utilities, the in-service date given

in the component engineering record is not

the date the component became operational, but rather the date the system or

plant became operational.

v Approximately 50% of the NPRDS data is

placed in the "unknown" or "other

devices" failure categories. This reflects the

practice of replacing a component or piece

part without establishing the reason for failure.

NPRDS failure descriptions use ambiguous

wording, making a determination of the

failure cause or aging classification difficult.

In view of the above strengths and weaknesses,

the NPRDS data can supply only relative information regarding which LWR safety systems and components have been significantly affected by aging

and the underlying cause of that aging. Accurate

determinations require analysis of plant records,

which is beyond the scope of this study. However, for

use in aging evaluations that rely on PRA techniques, only relative information is needed to modify the existing PRA information.

3.3 Aging Survey Analysis

The NPRDS data were utilized to create a data

base, which contains information about component

failures, identifying the nuclear steam system supplier, utility (not reported herein), system,

6
component, in-service date, and the components

engineering parameters. The components engineering parameters allowed collecting failure data that

are specific to a particular component type, size, or

capacity. Furthermore, the data base contains the

failure event date, system effect produced by the failure, cause category, and cause codes.

The failure reports in the NPRDS are organized

into nine categories referred to as cause categories.

These major categories refer to general causes, such

as engineering/design, installation error, wearout,

etc. A reported failure is then further characterized

by the addition of a cause code identifying the cause

of, or contributing factors to, the failure. These

codes refer to mechanical, electrical, or humanrelated causes of failure.

A relationship between the nine NPRDS cause

categories and the five general failure categories (as

defined in Section 2) was developed so that generic

issues could be examined. Figure 1 illustrates the

correlation between the nine NPRDS cause categories and the five aging survey failure categories.

Appendix A (Table A-l) presents the NPRDS

cause-category cause-code grouped into these five

failure categories. In practice, examination of the

cause code is not necessary to group the failures into

the five categories. Minimal error is introduced by

using only the NPRDS cause category. The resulting

aging-survey data base contains the number of failures, also called counts, specific to NSSS/system/

component combinations grouped into the five

failure categories. Associated with each failure

count are the system effect of the failure and the

component age at the time of failure.

For each system, failure fractions were calculated

for both the five broad failure categories and the

system effect categories. These fractions represent

an aggregation of all components within a system.

Failure fractions within a given system were calculated by dividing the total counts for a failure category by the total failure counts for that system.

System effect fractions were calculated in a similar

manner. Component/failure-category fractions

were calculated by dividing the total failure counts

per component/failure-category by the total failure

counts per component within the appropriate system.

Using the component/aging-failure-category

fractions, a rudimentary uncertainty study was performed using contingency table analyses. This study

addressed the question of whether similar components are more susceptible to failure due to aging,

depending upon the system in which they reside. A

standard statistical hypothesis test was performed

for each component to make this determination.

The hypothesis chosen for the test was that no differences in aging fraction existed for similar components placed in different systems. The tests were

performed at a family significance level of 0.05. The

significance level is defined as the probability that

test-indicated differences in aging effects exist, when

in fact there are no differences for the given component between systems. Family significance level

means that if no components have significant

between-system differences, one can expect 5°0/ of

the components to show significance. When the

analysis showed no statistically significant difference

in aging effects for the given component between

systems, the component failure counts for the component from all involved systems were combined to

calculate an overall aging fraction irrespective of system. A 95% confidence interval was calculated for

the composite fraction.

Aging-effect differences were found to be statistically significant for some components in different

systems. The data were examined to develop two

groups of systems where it was assumed that aging

differences did not exist within each group. This procedure resulted in two groups of systems. One group

contained the systems that indicated high aging

effects, and one group contained the systems that

indicated low aging effects. Each group could then

be characterized by estimating a composite aging

fraction based upon a larger data population base.

In addition to aging fractions, 95% confidence

intervals were calculated for each group. These confidence intervals for the proportion of faiures due to

aging were calculated according to the method

described in Reference 8, page 58.

To determine if aging failures increase over time, a

time-dependent study was performed on aging versus non-aging failures. The aging failures were tallied for each system/component combination in the

four age divisions. Aging fractions for the four age

divisions were calculated for the system/component

combination by dividing the total failures per

system/component/age-division combination by

the total failures per system/component combination.

3.4 Reported Failure Cause

Analysis and Aging

Classification

The methods used in the reported-failure-cause

identification and aging classification study are similar to those used in previous work performed at

7
Aging Survey Categories NPRDS Categories

Design & Installation

Engineering/Design

-0 - Manufacturing Defect

Installation Error

Aging Wearout

Testing & Maintenance o Maintenance/Testing

Human Related Incorrect Procedure

Operating Error

Other I Other Devices

I Unknown

MGH00974

Figure 1. Relationship of the NPRDS cause categories and the aging survey failure categories.

INEL for the Root Causes of Component Failures

Program. 2 This section expands on the different

aspects of the methodology utilized in this failure

cause identification effort.

"Failure cause" is defined as the underlying discernable cause of failure contained in the failure

report for a component. The NPRDS data base

codes provide some information about the underlying causes of the component failures. However, failure cause identification and aging classification

requires a manual examination of failure records. It

includes compiling and organizing specific information concerning the component and its failure. The

reported causes of failures were categorized and

assigned cause codes in accordance with the failure

cause categorization scheme presented in

Appendix B (Table B-2). Aging classification is

done in accordance with the guidelines given in the

same table.

The detail and depth of the information in the

NPRDS records is different for different components, systems, and plants. To accommodate these

differences, the failure cause categorization scheme

(or list) consists of three levels. Table I presents a

portion of the root cause categorization scheme to

show the general structure. This table shows the fulldepth level of detail for the first general category.

The entire categorization scheme is presented in

Appendix B, along with the cause-coding form

used to compile the data. A description of the cause

coding form and the correlation between NPRDS

records and the data fields on the form are also provided in Appendix B.

The "unclassifiable cause" codes were used when

the NPRDS records did not provide sufficient information to accurately determine the cause of the

component failure. Subjective interpretations of the

NPRDS narrative were not made. The "unclassiftiable cause" category is resolved into second- and

third-level codes. However, the third-level resolution

of the codes indicates the effect of the failure rather

than the actual cause.

Using the definition in Section 3.1, the aging

classification scheme was developed to allow a procedural approach to be taken in the identification of

aging failures. The procedure for classifying failures

is presented in Appendix B. Each failure cause code

is assigned one of three aging classifications: nonaging, conditional aging, or aging. Aging-related

failure cause codes are codes that always relate to

time-dependent effects. Examples of these timedependent codes are "erosion," "corrosion," and

8
Table 1. Example of the root cause

categorization scheme (full depth)

D Design/manufacturing/construction/quality

assurance inadequacy

DC Construction error or inadequacy

DCI Initial construction activity

DCR Retrofit construction activity

DE Design error or inadequacy

DEI Initial design activity

DER Retrofit design activity

DM Manufacturing error or inadequacy

DQ Quality assurance error or inadequacy

DQD Initial design quality assurance

activity

DQE Retrofit design quality assurance

activity

DQI Initial construction quality

assurance activity

DQM Manufacturer quality assurance

activity

DQR Retrofit construction quality

assurance activity

DR Plant definition requirements

inadequacy

DRI Initial definition activity

DRR Retrofit definition activity

aging-related in nature. In this case, the failure will

be assigned an "unknown" classification.

This failure cause identification study was oriented towards analyzing component failures of corn-*

plete systems. The system configurations used in the

failure-cause analysis were developed for use in the

Root Causes of Component Failure Program.2 The

component boundaries utilized are listed in Appendix C, along with examples of subcomponents and

piece parts of each component.

The failure modes, and definitions thereof, used

in the failure cause identification are given in Appendix D. The failure modes are, in general, directly

related to the failure modes used in PRA analysis.

Whenever the PRA failure mode definitions did not

encompass the type of failures reportable under the

NPRDS guidelines, certain failure modes were chosen and defined to represent the failure descriptions

actually encountered in the NPRDS data. For example, the "no failure" failure mode used for diesel

generators was developed to indicate when the diesel

generator remained operable, but a failure was

reported for a subcomponent of the diesel generator.

This failure could have resulted in the inoperability

of a redundant diesel generator subsystem.

The failure cause fractions, as used in this analysis, were derived for use in a probablistic risk analysis and are therefore specific to component and

failure mode. Manipulation of the reportedfailure-cause data base allowed the calculation of

cause fractions and aging fractions for the various

component/failure-mode/failure-cause combinations for each system. During this process, the

number of failures, or counts, was obtained for

each component/failure-mode combination, individual failure cause, and aging-classification/

failure-cause combination. The failure cause

fraction for each component/failure-mode combination was calculated by taking the number of

component failures in a specified failure mode

which are due to a given failure cause and dividing

by the total number of failures in that failure mode,

excluding the unclassified causes. The aging failure

cause fractions were calculated in the same manner.

Failure cause and aging failure cause fractions were

calculated for each system/component combination.

The aging-related cause fraction data presented in

this study reflect upper and lower bounds derived

from the operational data source. These bounds are

developed on the uncertainty encountered in accurate identification of aging-related causes on the

basis of the component failure descriptions. The categorization scheme defines when a failure should be

classified as related to aging or non-aging. When

"wear." Non-aging-related failure cause codes are

used for random events that cause immediate failure

of the component. Examples of these types of failure causes are "fire/smoke," "impact loads," and

"electromagnetic interference." Conditional aging

failures are classified as aging-related if information

in the failure report indicates some aging-related

effect code (from the categorization scheme) or

some keyword that indicates that a time-dependent

process is present. A failure categorized with a conditional aging code is classified non-aging if the failure description indicates that a random event caused

an immediate failure. In some instances, a failure

description contains enough information to allow

categorization with a conditional code but gives no

indication as to whether the failure was random or

9
insufficient information is contained in the failure

description, the aging classification is "unknown."

.* II These failures are then used to establish the upper

and lower bounds for the aging-related cause fractions. The upper bounds contain the failures classified as "unknown" as aging-related failures, while

the lower bounds contain them as non-aging-related

failures.

10
4. RESULTS

This section describes the results of the aging survey and the failure cause analysis. Engineering

insights are also presented.

4.1 Aging Survey Analysis

Data resulting from the survey of the failure category data base are presented in Appendix E. The

information is organized by specific system (auxiliary feedwater, component cooling water, etc.). Also

provided in Appendix E are (a) definitions of the

data fields and other information presented in the

tables and (b) summary tables for system/failurecategory, system/system-effect-categories, and

system/component/failure-category fractions.

These data constitute a rollup of the information

presented in the detailed aging survey tables, which

tabulate an extensive amount of data and have been

microfiched for the purpose of this publication.

Table 2 is an illustration of the format of these

tables. Some components were broken down only to

the major NPRDS components designation, as

shown by the "SUPORT" data. For other components, the component engineering data were utilized

to provide a more detailed breakdown, as shown in

Table 2 for the NPRDS major category "VALVE."

The detailed breakdown using the component engineering data depended on the possible safety importance of the component and the amount of data

available in the NPRDS. In all nine systems, valves

were broken down because they are an important

component in PRA analysis. Instrumentation components were only broken down in the reactor protection trip system because in that system, the

amount of data for instrumentation components is

extensive.

The fractions in percent (by system) for the five

major failure categories are shown in Figure 2. As

illustrated, the dominant failure categories are

"aging" (31'%) and "other" (50%). Human-related

failures only contribute about 1.5% to the total of

failures reported. Failures in the "testing and maintenance" and "design and installation" categories

are responsible for approximately 7.5% and 10%,

respectively.

The "other" category consists of failures for

which the cause of failure was not determined or

could not be assigned to another category. The size

of the "other" category is indicative of the difficulties encountered in determining the cause of failure

for certain components and the practice of replacing

a component or piece part without establishing the

reason for failure. Therefore, it is likely that some of

the failures recorded in the "other" category were

caused by unidentified aging mechanisms. It is recognized that this concern could also apply to the

aging category. However, examination of the failurecause study, where the number of unclassified failures is significantly smaller, indicates generally

higher component aging fractions and tends to support the conclusion about the "other" category.

Figure 2 also indicates that normally operating

fluid systems, such as the service water, main feedwater, and component cooling water systems,

exhibit relatively high aging fractions; while standby

safety fluid systems, such as the high-pressure injection, residual heat removal, and standby liquid control systems, exhibit lower aging fractions. The aging

fractions for the reactor protection trip and

Class IE electrical power distribution systems fall

between the higher values of the active fluid systems

and lower values of the standby fluid systems due to

the mixture of components involved and their operational modes.

The relationship of failures to reported system

effects is presented in Figure 3. Examination of this

figure indicates that, although the fractions in the

"system function unaffected" category are slightly

higher, there was no clearly dominant system effect

category. It is notevorthy, however, that very few

failures caused "loss of system function."

Figures 4 and 5 illustrate the relationship of

aging fractions for selected components in different

systems. These figures represent only a subset of the

data presented in Appendix E. The components

selected for Figure 4 were chosen because they tend

to have high aging fractions in some systems. The

four instrumentation components illustrated in Figure 5 were selected because they appeared in all nine

systems and exhibited some aging failures; therefore

some comparison could be made. The numbers

shown with each bar are the number of failures associated with that component in that system.

A rudimentary uncertainty study was performed

on the system/component aging fractions to identify

which components exhibit a system-dependent

aging relationship. The results of this study are presented in Tables 3 and 4. The components were

divided into two groups. Table 3 contains components for which the systems exhibited no statistical

dependency related to aging effect. Table 4 contains

components for which system dependency of aging

11
Table 2. Example of detailed aging survey tables

Age of Component and Fa i I ure Categorya

Sys Sys 0-4.9 Years

Failure Eff Eff

NSSS System ComDonent Total No. Co b D A T H 0

C CFA SUPORT

5-9.9 Years

D A T H 0

10-14.9 Years 15-20 Years

D A T H 0 D A T H 0

Support/

Snubbe rs

101 A I I _ I I [] I Z I L 1 r I i Z _ I Z I 

11B I.21..WL....1 1[2(U1 21 I-~W1 L 1.

3 C I I I I - 11 1_1 2 1 1 1 1 I .1 . .1 . ..1. I . |

3D _ I i i i I I 1 21 1 [..1 i 11 I 1 3 1 1 3

82 E 1 _6i 21 1 11 91 i1 11 61 11 1 441 1 _1 I1 1i -f I I I I i I i

C CFA VALVE

Check Valve 29 A I I 7 1 D I _ i I I I I I I I I I-I I I I

11 B I 11 31 1 1 31 [ 11 3 .I I11 1 1 1 1, I I I 1 I _ I 1

6 C I I 1 f 11 [__11 31 1 1 1 1 - 1- I I I I I I I

8 E i 3 1 i - I 1 I 1 i - 1 4 3 1 1 i i i 11 I i

t'J Manual Valve 25 A 1 f I I -1 - I I I I I f I I I -7 -I I [ I I [, _

5 B 1 1 1 1 1 11 1 1 [ 1 1 1 l 1 1 1 1 1 1 i i I i - 4 C I 1 21 1 1 1 1 _[ Zl I I I I I I I I I I I I I 1

3 E i) I i 2 - 1- - - i 1 3 [ 1 31 1 1 73 1 i 3 I I i I I , I i l

Mechanical

Va I ve

Motor- 1

Ope rated

Va lve

155 2 A I I iI ] 3 1 L _ 1i I( I 

2 C i I i i

8 E i 1 i I i II | 1 I'l8l 1 2I I H i i 3

25 B [ 5 1 1 ji 6 5 1 4 1 1 ] 1 1 | i | 1 I I I I i

25 C 1 1 1 8 1 1 1 2 ( 1 81 16 I 41 1 8- 21 21 i 1 I 1 i i I i

60 E 1 31 11 1 61 1 21 101 41 1 2811 11 31 1 1 2] 1 1 1 1 1

a. Failure categories are: D-design and installation; A-aging; T-testing and maintenance; H-human related; and O-other.

b. System effect categories are: A-loss of system function; B-degraded system operation; C-loss of redundancy; D-loss of subsystem/channel; and E-systemn function unaffected.
Design and Testing and Human

Installation Aging Maintenance Related l l Other

- H~~~i-- F-H H-H] i -1-

0

0

L..

LL

0.

En.JLJ/ LLU -, M -Q=3: U.U.Q=3M-Q t C UL~uQC3: C/= LL L 0, LL ~ UvR :3 J I 0 ~ -

MGH587- 1

Figure 2. Relationship of the failure category fractions by system.

Degraded System Loss of Loss of System Function

Operation Redundancy Subsystem/Channel Unaffected

l~ ~~ - 11 11 11 1

0.7

0.6

0.5

C) 0

0

U0.4

0.3

0.2

0.1

L U .. L C J L L~~~~~~~ - - ~- M C

U-L)U-fL=3:M- - -- U. =30- 6 - =3M U..c0U..-= (n

<U2= 00 M <U2= v)0 - < 2==w0 M U2 = 0 = <U2O=b/)

MGH587-2

Figure 3. Relationship of the system effect fractions by system.

13
Valve Operators Pumps Circuit Breakers Heat Exchangers

0

U-

~~:3:3:Tc,-jw j 3c3w3:W~wojwj 3:3cn:0xwju <U- Lfa )c LL Li : O- L L-E3 LUL C :M L )L .M3

MGH587-4

Figure 4. Relationship of the component aging fractions by system.

0.9

0.8

Switches

0.6

Recorders/ Transmitters/

Controllers Indicators Elements

I- 1 m t a

0

C)

LL

0.5

N

3-.3~~:Wxw-ww 3:33:Ln~~~~~wujcj

U- -'M U-a.= L.-G 3 U U) -= 3 C - - - G L, - ~:co- C U (U L CLM3 : -a <U 2 = =~~Lo Z (n I)o = <Ur.==( ) c

MGH587-3

Figure 5. Relationship of the instrumentation component aging fractions by system.

14
Table 3. Uncertainty study: no statistical system dependency related to aging

Component

Accumulatora

Air dryb

Annunciatora

Battery charging unitb

Blower-compressorb

Circuit breakerc

Electrical conductor

Electronic power supplyd

Engined

Filterd

Generator/alternator/inverterd

Heat exchangers

Heaterd

Instrumentation-computation modulec

Instrumentation-controllerC

Instrumentation-indicator/recorderd

Instrumentation-isolation deviced

Mechanical function unitd

Motorc

Piped

Relayd

Transformerb

Turbined

Valve operatorc

Aging

Fraction

0.21

0.50

0.40

0.33

0.62

0.23

0.10

0.25

0.26

0.57

0.24

0.50

0.11

0.28

0.25

0.22

0.37

0.25

0.47

0.56

0.23

0.13

0.13

0.26

95%

Confidence

Interval

(0.06, 0.46)

(0.07, 0.93)

(0.05, 0.85)

(0.27, 0.39)

(0.55, 0.69)

(0.19, 0.27)

(0.03, 0.24)

(0.20, 0.31)

(0.22, 0.30)

(0.47, 0.67)

(0.19, 0.28)

(0.40, 0.60)

(0.03, 0.26)

(0.25, 0.31)

(0.20, 0.31)

(0.18, 0.27)

(0.20, 0.56)

(0.15, 0.39)

(0.37, 0.57)

(0.31, 0.78)

(0.19, 0.27)

(0.04, 0.31)

(0.06, 0.25)

(0.23, 0.29)

a. The deletion of systems with expected cell count less than 4.7 led to deletion of all systems. Therefore, all data were used to

estimate aging fraction and confidence interval.

b. One system/component combination (and no difference test).

c. Systems with expected cell count of less than 4.7 were deleted. The remaining system/component data were used to calculate the

aging fraction and confidence interval.

d. The deletion of systems with expected cell count less than 4.7 led to one system/component combination (and no difference

test).

effects could be statistically determined. Only five

components demonstrated any statistically significant differences between aging fractions across systems. These components are switches, transmitters,

pumps, supports, and valves.

Comparing the aging fractions illustrated in Figures 4 and 5 and the results of the uncertainty study

on the system/component aging fractions leads to

several observations. Figures 4 and 5 clearly indicate which system/component combinations are

being impacted by aging phenomena. The uncertainty study further supports these results. Figure 4

indicates that in normally operating systems, valve

and pump performance is strongly affected by

aging. Furthermore, valves and pumps associated

with the diesel engine auxiliary systems in the

Class IE electrical power distribution systems are

strongly affected by aging. These components usually reside in highly vibrational environments. It is

suspected that this type of environment causes the

high numbers of failures. The pumps in the standby

liquid control system display a very high aging fraction for a standby safety system. This observation is

supported by the fact that the standby liquid control

system is a boric acid injection system, and the boric

acid environment can be very damaging to pugp

15
Table 4. Uncertainty study: statistical system dependency related to aging

95 0o

Aging Confidence

Component Fraction Interval Systems

Instrumentation-switcha

Instrumentation-transmittera

Pump

Supportsa

Valve

0.06

0.20

0.55

0.03

0.60

0.31

0.37

0.12

0.54

0.37

(0.04, 0.10) RHR, HPIS

(0.17, 0.23) SWS, RPS, IE

(0.49, 0.60) RPS, MFW

(0.02, 0.05) AFW, HPIS, RHR

(0.55, 0.65) SBL, CCW, IE, SWS

(0.26, 0.37) MFW, RHR, HPIS, AFW

(0.21, 0.56) HPIS

(0.07, 0.18) MFW, RHR

(0.52, 0.57) IE, SWS, MFW, AFW

(0.34, 0.41) RHR, CCNV, HPIS, SBL

a. Systems with expected cell count of less than 4.7 were deleted. The remaining system/component data were used to calculate the

aging fraction and confidence interval.

seals The uncertainty study supports these

observations-both valves and pumps showed statistically significant differences between aging fractions across the nine systems. The study indicated a

higher composite aging fraction (0.60) for pumps in

the component cooling water and service water systems (normally operating fluid systems) and the

standby liquid control and Class lE electrical power

diesel auxiliary systems (severe operational environment) than for pumps in the main feedwater, residual heat removal, high-pressure injection, and

auxiliary feedwater systems (aging fraction of 0.31).

Valves displayed similar results, indicating a higher

composite aging fraction (0.54) in the service water,

main feedwater, and auxiliary feedwater systems

(normally operating fluid systems) and Class IE

electrical power diesel auxiliary systems (severe operational environment) than in the residual heat

removal, component cooling water, high-pressure

injection, and standby liquid control systems (aging

fraction of 0.37).

Valve operators in the diesel engine auxiliary subsystems of the Class lE electrical power distribution

systems reside in a hi v o e

Figure 4 shows that these valve operators are significantly affected by aging compared with valve operators in the other eight systems. However, this

observation is not supported by the uncertainty

study.

Figure 4 also indicates that failures of the heat

exchangers in the main feedwater systems are frequently due to aging. These heat exchangers are used

as feedwater heaters and are located downstream of

the turbine exhaust. It is suspected that the steam

environment accelerates the degradation process.

While the figure implies that heat exchanger aging is

significantly more important in the main feedwater

systems, the uncertainty study indicated no statistically significant differences for heat exchangers

across the nine systems.

Figure 5 indicates that the aging fractions for

solid-state instrumentation components do not vary

greatly from system to system. The uncertainty

study supports this observation and further illustrates (on the basis of composite aging fractions)

that the effect of aging on solid-state component

failures is minimal relative to other components.

Furthermore, the only instrumentation components

showing statistically significant differences across

the systems were switches and transmitters.

Table 5 presents the time-dependent aging fractions for system/component combinations having at

least 50 failure counts. While the data exhibit definite time dependencies in aging-related failures,

there is no apparent pattern to the aging fraction

results. In numerous cases, the aging fractions were

higher in the 5-to-9.9 year division; while the aging

fractions in the 15-to-20 year division were virtually

16
Table 5. System/component combination time-dependent aging fractions

Fraction

Total

System Component Failures 0-4.9 yr 5-9.9 yr 10-14.9 yr 15-20 yr

IE Battery/battery charging unit 243 0.107 0.160 0.053 0.004

IE Blower 217 0.147 0.304 0.166 0.005

1E Circuit breaker 247 0.081 0.057 0.057 0.012

RHR Circuit breaker 72 0.083 0.014 0.083 0.014

IE Engine 512 0.059 0.074 0.121 0.000

SWS Filter 101 0.248 0.287 0.030 0.000

IE Generator/alternator/inverter 87 0.069 0.092 0.069 0.000

HPIS Instrumentation: switch 154 0.026 0.013 0.000 0.000

RHR Instrumentation: switch 179 0.022 0.050 0.017 0.000

RPS Instrumentation: switch 480 0.081 0.062 0.037 0.008

RPS Instrumentation: controller 201 0.114 0.040 0.070 0.015

RPS Instrumentation: recorder 204 0.029 0.088 0.088 0.059

RPS Instrumentation: computation module 865 0.110 0.105 0.047 0.012

RPS Electronic power supply 256 0.082 0.129 0.023 0.016

AFW Instrumentation: transmitter 78 0.013 0.077 0.013 0.000

HPIS Instrumentation: transmitter 142 0.070 0.028 0.014 0.000

MFW Instrumentation: transmitter 82 0.061 0.098 0.012 0.000

RHR Instrumentation: transmitter 70 0.000 0.014 0.014 0.000

RPS Instrumentation: transmitter 766 0.093 0.050 0.040 0.005

IE Mechanical function unit 55 0.036 0.145 0.073 0.000

SWS Motor 66 0.091 0.121 0.167 0.000
Table 5. (continued)

Fraction

System

IE

AFW

CCW

HPIS

SwS

IE

RPS

MFW

RHR

Component

Total

Failures

00 AFW

IE

AFW

CCw

HPIS

MFW

RHR

SBL

SwS

AFW

CCW

HPIS

MFW

RHR

SWS

Pump

Pump

Pump

Pump

Pump

Relay

Relay

Support

Support

'Rrbinc

Valve

Valve

Valve

Valve

Valve

Valve

Valve

Valve

Valve operator

Valve operator

Valve operator

Valve operator

Valve operator

Valve operator

61

111

56

86

252

89

339

60

55

102

0-4.9 yr

0.197

0.063

0.089

0.070

0.159

0.067

0.056

0.036

0.020

0.050

0.236

0.261

0.063

0.058

0.104

0.123

0.058

0.182

0.133

0.019

0.042

0.087

0.075

0.122

5-9.9 yr

0.246

0.027

0.321

0.070

0.198

0.067

0.071

0.091

0.069

0.050

0.188

0.159

0.270

0.167

0.284

0.274

0.072

0.252

0.086

0.135

0.073

0.122

0.127

0.122

10-14.9 yr

0.180

0.153

0.250

0.174

0.198

0.101

0.100

0.000

0.029

0.017

0.139

0.091

0.048

0.093

0.122

0.067

0.101

0.114

0.029

0.058

0.091

0.096

0.026

0.045

15-20 yr

0.000

0.000

0.000

0.000

0.004

0.011

0.000

0.000

0.000

0.017

0.006

0.000

0.000

0.003

0.012

0.000

0.000

0.003

0.000

0.000

0.000

0.009

0.000

0.000

165

276

63

312

335

252

69

369

105

52

165

115

228

311
zero. (Very few components have experienced an

exposure time this long.) It is expected that the pattern would show an increase in aging failures with

the increase in the age of the component up to the

useful lifetime of the component. It is not reasonable to expect that the components studied have useful lifetimes only in the range of 5 to 10 years. This

is especially true of the component piece parts or

internals that age more rapidly than component

structural parts. Additionally, the data utilized in

this study are impacted by variables such as plant

maintenance practices and the age of the plant.

Plant maintenance often results in the complete rejuvenation of a component; however, occasionally,

plant maintenance results in accelerated component

degradation. The impact of these variables cannot

be assessed from the data contained in the NPRDS

data base. To address the effectiveness of maintenance on controlling aging, plant-specific component maintenance histories would have to be studied.

This type of analysis was beyond the scope of the

current study.

4.2 Reported Failure Cause

Analysis

Table 6 summarizes the service water and

Class IE electrical power distribution systems failure information obtained in the failure-cause study.

The complete reported cause of failure data are presented in Appendix F. The data presented in Table 6

consist of the total failures, lower bound aging total,

upper bound aging total, lower bound aging fraction, and upper bound aging fraction for those components having five or more failure counts. The data

presented are a rollup of the specific component/

failure-mode cause fractions for those components

having five or more failure counts. From the information presented, it can be seen that the service

Table 6. Table of SWS and Class 1E component failures and aging fractions as determined

by the reported causes of failure study

Componentsa

Total

Failures

Lower

Bound

Aging

Total

Upper

Bound

Aging

Total

Lower

Bound

Aging

Fraction

Upper

Bound

Aging

Fraction

Service Water System

Check valvesb

Strainers

Motor-driven pumpsb

Pneumatic-operated valves

Hand control valves

Circuit breakersb

Motor-operated valvesb

Total

System aging fraction

31 27 28

21 17 18

167 129 140

47 36 45

17 11 12

17 9 12

111 43 93

411 272 348

0.87

0.81

0.77

0.77

0.65

0.53

0.39

0.66

0.90

0.86

0.84

0.96

0.71

0.71

0.84

0.85

Class JE Electrical Power Distribution System

Battery chargersb

Batteriesb

Diesel generatorsb

Circuit breakersb

Invertersb

Total

System aging fraction

35

10

113

10

63

231

18

5

55

3

18

99

34

10

75

6

38

163

0.51

0.50

0.49

0.30

0.29

0.43

0.97

1.00

0.66

0.60

0.60

0.71

a. Components have been ordered by lower bound aging fractions.

b. In-depth engineering studies of these components have been implemented as part of the Nuclear Plant Aging Research Program

(Reference 1).

19
water system has a lower bound fraction expressed in

percent of 66% and an upper bound of 85°10 for

aging-related failures; the Class IE power distribution system exhibited 43% and 71°10, respectively.

Table 7 summarizes the failure data from this

study for selected systems and components, including failure mode and dominant failure causes for the

respective failure mode. The data are presented for

those component/failure-mode/failure-cause combinations that had five or more documented events

per failure cause; therefore, only the major categories of failure causes are presented.

Examination of Tables 6 and 7 indicates that the

service water system component having the highest

potential system impact due to aging failures is the

motor-driven pump. There were 91 failures coded

for the failure mode "fails to run," and 64 failures

coded for the "external leakage" failure mode.

"Wear" and "foreign materalsiu a he

dominant reported failure causes of these two failure

modes. The dominant aging-related failure cause is

"wear," with aging-related failures comprising 77%

to 84%1 of the total pump failures (Table 6).

An inspection of the failure records pertinent to

service water system motor-driven pumps shows that

the failures coded under the failure mode "external

leakage" were caused by the wear of the pump seals

and pump packing or foreign material intrusion into

the pump seals. The foreign material intrusion

related primarily to sand and other particulates

sometimes found in the influent water.

The wear mechanism for the motor driven pump

failures coded under the failure mode "failure to

run" is associated with the pump itself, not just the

seals and packing. The wear mechanism is also associated with the motor of the motor-driven pump.

Sand and other particulates found in the influent

water are the dominant cause of the failures coded as

"foreign material intrusion."

The service water system components with the

second highest potential for aging impacts on system

operation are motor-operated valves. The resulting

potential aging fraction range (in percent) is 39% to

84%. Although its importance is somewhat reduced

due to the relatively small number of failures, the

largest aging-related failure cause fraction associated with service water system motor-operated

valves is for "wear" and the failure mode of "external leakage." The piece part most affected by

"wear" is packing. The largest number of failures

occurred for the failure mode "fails to close."

Inspection of the failure records indicates that dominant aging failure cause "wear" often caused the

failure of the valve stem connection to the valve

operator. Table 7 further indicates that the failure

cause of "out of adjustment" for motor-operated

valves displays a potentially high aging contribution

for the failure modes of "fails to close," "fails to

open," and "fails to operate as required." Examination of the failure records reveals that "out of adjustment" is associated with the valve operator and the

time requirement for actuation of the valve movement.

Service water system check valves are significantly

affected by aging. The largest potential aging fraction was calculated for service water system check

valves (Table 6, 0.87 to 0.90). The dominant failure

mode is "internal leakage," with the dominant aging

failure causes of "wear" and "corrosion."

Examination of the failure records indicates that the

piece parts most affected by wear are the valve seat

and valve disc, as would be expected. Failures of the

valve body and the valve internals are attributable to

corrosion.

Service water system strainers exhibit the second

highest potential aging-related failure fraction

(Table 6, 0.81 to 0.86). Inspection of the failure

records indicates that packing wear and plugging

due to foreign material in the influent water are the

dominant contributors to failure.

The diesel generators are the largest single contributor of failures for the Class IE systems. This is,

in part, because of the component boundaries developed for the diesel generator for the failure cause

study. Aging-related failures comprise 49% to 66%

of the total failures, and the largest single aging diesel generator failure cause is "wear." The failure

records and data indicate that the wear failures are

distributed over four diesel generator subsystems:

diesel cooling water, diesel fuel oil, diesel lube oil,

and diesel starting air. The components most

affected are valves and pumps.

Inverters in the instrument and uninterruptible

power systems of the Class IE system also account

for a relatively large failure count. These failures are

dominated by electrical failures. Examination of the

NPRDS failure records indicates that the major contributors to these electrical failures are blown fuses,

defective fuses, and defective solid-state components. There were few aging-related failures found

for this component.

20
Table 7. Reported failure cause identification summary

Fraction

System/Components

Essential service water

Failure Mode

Total

Counts

Failure

Cause

Lower

Bound

Aging

Upper

Bound

Dominant Failure Cause Aging

Check valves Internal leakage 25 Wear

Corrosion

0.480

0.240

0.480

0.240

0.480

0.240

Motor-operated valves External leakage

Fails to open

Fails to close

7

27

43

17

Wear

Binding/out of adjustment

Wear

Binding/out of adjustment

Binding/out of adjustment

0.714

0.296

0.140

0.535

0.294

0.714

0.037

0.140

0.000

0.059

0.714

0.222

0.140

0.488

Fails to operate 0.235

as required

Pneumatic-operated valves External leakage

Fails to close

Fails to operate

as required

5

1 5

13

Wear

Wear

Wear

1.000

0.333

0.385

1.000

0.333

0.385

1.000

0.333

0.385

Motor-driven pumps Fails to run

External leakage

Loss of function

Plugged

91

64

13

8

Wear

Binding/out of adjustment

Foreign materials intrusion

Wear

Foreign materials intrusion

Wear

Foreign materials intrusion

0.319

0.110

0.253

0.703

0.141

0.615

0.750

0.319

0.011

0.176

0.703

0.125

0.615

0.500

0.319

0.066

0.176

0.703

0.125

0.615

0.500

Strainers

Instrument and uninterruptible power supply system-Class IE

Inverters Loss of function 63 Design error or inadequacy

Wear

Electrical overload

Faulty module

Short circuit

0.079

0.079

0.143

0.286

0.127

0.000

0.079

0.000

0.079

0.016

0.016

0.076

0.016

0.222

0.079
Table 7. (continued)

Fraction

System/Components Failure Mode

Total

Counts Dominant Failure Cause

Failure

Cause

Lower

Bound

Aging

Upper

Bound

Aging

DC power supply system-Class IE

Battery chargers Loss of function 35 Faulty module 0.657 0.400 0.657

Emergency on-site power supply system

Diesel generator Fails to run

No failure

46

49

Wear

Water intrusion

Wear

Cyclic fatigue

0.304

0.184

0.122

0.102

0.304

0.041

0.122

0.102

0.304

0.061

0.122

0.102

t'j
5. CONCLUSIONS

This section discusses the conclusions drawn

from the aging survey and reported failure-cause

analyses.

5.1 Aging Survey Analysis

A data base consisting of operational events

recorded in the NPRDS has been generated for

selected LWR safety and support systems. Analyses

performed on the data provided several insights

concerning the effect of aging failures on the

selected systems. It was determined that for the systems in general many nuclear power plant component failures are due to aging, while failures

categorized as "human related" were few. The

"other" category is the largest failure category. It

consists of failures for which the cause either was

not determined or could not be assigned to another

category. The size of this category is indicative of

the difficulties encountered in determining the

cause of failure for certain components and the

practice of replacing a component or piece part

without establishing the reason for failure.

The analysis established that normally operating

fluid systems, such as the service water, main feedwater, and component cooling water systems,

exhibit the highest aging failure fractions, with

pumps and valves being the components most

affected. However, there are significant exceptions

to this finding concerning operational mode. Components in some standby systems (such as pumps in

the standby liquid control system and valves and

pumps in the diesel subsystems of the Class IE

electrical power distribution systems) also display

high aging fractions. It is suspected, as a result of a

minimal systems analysis, that these standby system components are adversely affected by their

operational environment.

While the data exhibit a variety of time dependencies of the aging-related failures, the timedependent aging analysis did not yield any

definitive results in terms of component- or systemspecific aging patterns. The data utilized in this

study are impacted by variables such as plant maintenance practices and the age of the plant. Some of

the information necessary to assess the impact of

these variables on aging is not available from the

NPRDS source data.

5.2 Reported Failure Cause

Analysis

The failure cause identification analysis has provided insights into the effects of aging-related failures in service water and Class IE electrical power

distribution systems. The analysis established that

the service water system, a normally operating fluid

system, is significantly affected by aging (lower

bound system aging fraction of 0.66 and upper

bound system aging fraction of 0.85); the Class IE

electrical power distribution systems, however, are

somewhat less affected by aging (lower bound system aging fraction of 0.43 and upper bound system

aging fraction of 0.71).

The specific service water system components

that exhibit significant aging-related failures are

check valves (87% to 90%), strainers (81% to

86%), motor-driven pumps (77% to 84%o), and

motor-operated valves (39% to 84%). "Wear" was

the significant aging mechanism affecting the

valves. Motor-driven pump and strainer failures

were dominated by "wear" and "foreign material

intrusion." These aging mechanisms -re prominenw

in the service water system due to sand and other

partcultes ormllypresnt n te i~nfluent water.

Failures of the diesel generators dominated the

Class IE electrical power distribution system and

exhibited an aging fraction of 0.49 to 0.66. The

aging mechanism most prominent for the diesel

generator was "wear," which comprised 30% of

the aging-related failures. The subcomponents failing due to "wear" were the valves and pumps

located in the cooling water, fuel oil, lube oil, and

starting air subsystems of the diesel generator.

In conclusion, while it can be easily seen that

aging failures contribute approximately 31°% to the

recorded failures in the systems examined, a quantitative statement about risk or safety requires the

use of PRA methods.

23
6. REFERENCES

1. Nuclear Plant Aging Research (NPAR) Program Plan, NUREG-1 144, July 1985.

2. D. G. Satterwhite, L. C. Cadwallader, W. E. Vesely, B. M. Meale, Root Causes of Component

Failures Program: Methods and Applications, NUREG/CR-4616, EGG-2455, December 1986.

3. W. L. Greenstreet, G. A. Murphy, D. M. Eissenberg, Aging and Service Wear of Electric MotorOperated Valves Used in Engineered Safety-Feature Systems of Nuclear Power Plants, Vol. 1,

NUREG/CR-4234, ORNL-6170-41, June 1985.

4. M. Subudhi, E. L. Burns, J. H. Taylor, Operating Experience and Aging-Seismic Assessment of

Electric Motors, NUREG/CR-4156, BNL-NUREG-51861, June 1985.

5. J. C. Watkins et al., A Study of Typical Nuclear Containment Purge Valves in an Accident Environment, NUREG/CR-4648, August 1986.

6. J. W. Vause et al., Aging of Nuclear Station Diesel Generators: Evaluation of Operating and Expert

Experience, NUREG/CR-4590, October 1986.

7. L. C. Meyer, Nuclear Plant Aging Research on Reactor Protection Systems (Draft), NUREG/

CR-4740, EGG-2467, to be published.

8. N. L. Johnson and S. Kotz, Discrete Distributions, Boston: Houghton Mifflin Company, 1969.

24
APPENDIX A

ACRONYMS AND CODES

FOR THE AGING FAILURE SURVEY

A-l
APPENDIX A

ACRONYMS AND CODES

FOR THE AGING FAILURE SURVEY

Table A-1. Failure category assignments for NPRDS codes

Design & Installation (D)

NPRDS Cause Categories: A -

C -

D -

NPRDS Causes: AB

AC

AF

AG

AY

AZ

BC

BE

BF

Engineering/Design

Manufacturing Defect

Installation Error

Foreign/Incorrect Material

Particulate Contamination

Weld Related

Abnormal Stress

Electrical Overload

Material Defect

Out of Mechanical Adjustment

Dirty

Blocked/Obstructed

Aging (A)

NPRDS Cause Categories: H - Wearout

NPRDS Causes: AC Particulate Contamination

AD Normal/Abnormal Wear

AE Lubrication Problem

AG Abnormal Stress

AL Set Point Drift

AR Insulation Breakdown

AS Short/Grounded

AT Open Circuit

AU Contacts Burned/Pitted/Corroded

AV Connection Defective/Loose Parts

AW Circuit Defective

AX Burned/Burned Out

AY Electrical Overload

AZ Material Defect

BB Mechanical Damage/Binding

BC Out of Mechanical Adjustment

BD Aging/Cyclic Fatigue

BE Dirty

BF Blocked/Obstructed

BG Corrosion

BH Out of Calibration

F - Maintenance/Testing

Testing & Maintenance (T)

NPRDS Cause Categories:

NPRDS Causes: AG

AN

AR

AW

AY

BC

BJ

Abnormal Stress

Incorrect Procedure

Insulation Breakdown

Circuit Defective

Electrical Overload

Out of Mechanical Adjustment

Incorrect Action

A-3
Table A-1. (continued)

Human Related (H)

NPRDS Cause Categories:

NPRDS Causes:

Other/Unknown (0)

NPRDS Cause Categories:

NPRDS Causes:

B

E

- Incorrect Procedure

- Operating Error

AA Foreign/Wrong Part

AE Lubrication Problem

AL Set Point Drift

AM Previous Repair/Installation Status

AN Incorrect Procedure

AV Connection Defective/Loose Parts

AW Circuit Defective

AY Electrical Overload

BC Out of Mechanical Adjustment

BJ Incorrect Action

J - Other

K - Unknown

Any of the causes apply as long as the cause

categories are the two listed above.

Table A-2. NPRDS component acronyms

ACCUMU

AIRDRY

ANNUNC

BATTRY

BLOWER

CKTBRK

ELECON

ENGINE

FILTER

GENERA

HEATER

HTEXCH

IBISSW

ICNTRL

INDREC

INTCPM

IPWSUP

ISODEV

IXMITR

MECFUN

MOTOR

PIPE

PUMP

RELAY

SUPORT

TRANSF

TURBIN

VALVE

VALVOP

Accumulators

Air/Gas Dryers

Annunciator Modules

Batteries and Chargers

Blowers (Compressors)

Circuit Closers/Interrupters

Electrical Conductors

Engines, Internal Combustion

Filters/Strainers

Generators/Inverters/Alternators

Heaters, Electric

Heat Exchangers

Instrumentation, Bistable/Switch

Instrumentation, Controllers

Instrumentation, Indicators/Recorders

Instrumentation, Integrator/Computation Module

Instrumentation, Electronic Power Supply

Instrumentation, Isolation Device

Instrumentation, Transmitter/Element

Mechanical Function Units

Motors

Pipe, Fittings

Pumps

Relays

Shock Suppressors and Supports

Transformers

Thrbines

Valves and Dampers

Valve Operators

A-4
Table A-3. NPRDS system effect descriptions

A - Loss of System Function - A component failure that, by itself, results in the system being

unable to perform its intended function (i.e., all trains, channels, etc., inoperable).

B - Degraded System Operation - The system is capable of fulfilling its intended function, but

some feature of the system is impaired.

C - Loss of Redundancy - Loss of one system functional path.

D - Loss of Subsystem/Channel - A partial loss of system functional path.

E - System Function Unaffected - Failure did not affect the operation of the system.

A-5
APPENDIX B

REPORTED FAILURE CAUSE IDENTIFICATION INFORMATION

B-1
APPENDIX B

REPORTED FAILURE CAUSE IDENTIFICATION INFORMATION

Failure Cause Coding

This appendix contains information concerning

the failure cause coding form (Figure B-I) used to

compile the analysis data. The data fields of the

coding form were developed such that necessary

information could be gathered in a concise manner

amenable to constructing a failure cause data base.

Many of the fields were obtained directly from the

Nuclear Plant Reliability Data System (NPRDS)

record format. Table B-I shows those fields having

one-to-one correspondence.

The failure cause coding form used for this study

is a modification of the form used in the Root

Causes of Component Failures Program. The following new fields were added: System Initial Conditions, System Effect, Event Date, In-Service

Date, Age, and Out of Service. The latter four

fields are discussed in the footnotes of Figure B-1.

A field called "Aging" was also added to indicate if

the failure was considered to be age-related. This

was necessary to tabulate the aging failures, since

many causes of failure may or may not be agerelated. A field for the report number was included

to relate the coding form to the specific NPRDS

record. Two fields (Secondary Failure ModeComponent and Secondary Failure ModeSubcomponent) were also added. These fields

provide more detail about how the component

itself and its piece parts failed.

Additional information concerning the failure

cause coding can be found in Root Causes of

Component Failures Program: Methods and Applications, NUREG/CR-4616, EGG-2455, December

1986.

Failure CauselAging

Categorization Scheme

The failure cause categorization scheme and

guidelines for aging failure classification are presented in this Appendix. This categorization

scheme is based upon the failure cause categorization developed for use in the Root Causes of Components Failures Program and provides a means of

identifying and collecting reportable mechanisms

of failure for components contained in reactor systems. For use in the NRC Nuclear Plant Aging

Research (NPAR) Program, the scheme has been

expanded to provide guidelines for identifying

aging-related failures to the degree of certainty

allowable by the event data source. This entails

identification of aging-related failures on the basis

of certain causes or effects described in the failure

record narratives.

The categorization scheme consists of three levels. The first, and most general, level of failure

cause categorization is represented by a onecharacter code. It is comprised of five categories:

design/manufacturing/construction/quality

assurance inadequacy (D), environmental

stress (E), human actions (H), supervision/

management inadequacy (S), and unclassifiable

cause (U).

The second level of categorization is a further

resolution of the first level. For example,

supervision/management inadequacy (S) is

divided into the following second-level headings:

contractor/other personnel inadequacy (SC),

inadequate human environment (SH), procedures

inadequacy (SP), and training inadequacy (ST).

All second-level failure causes are designated by 2-

character codes.

The third level of cause resolution is the finest

available for use and is designated by a 3-character

code. For example, the second-level entry for procedures inadequacy (SP) is divided into the following third-level causes: calibration procedures

(SPC), maintenance procedures (SPM), operational procedures (SPO), quality assurance procedures (SPQ), and testing/surveillance procedures

(SPT). It should be noted that for the purpose of

aging-related failure determination, many of the

third level causes tend to be more related to failure

effect codes than true failure causes that would be

determinable by component engineering studies.

Although the unclassifiable cause (U) category is

broken down into second and third levels, the thirdlevel codes indicate the effect of the failure and are

not considered to be true failure causes. These

third-level entries are used because the failure

causes are unidentifiable from the failure report.

Using the definition in Section 3.1, the aging

classification scheme was developed to allow a procedural approach to be taken in the identification

of aging failures. Each failure cause code is

B-3
Plant ID:

Docket Number:

Report Type: NPROS

Report Number:

Plant Type:

PC Record Number:

Person Date

Coding:

Quality Assurance:

Failure Sequences:

Sequences this page :

CCF:

Plant Group:

Manufacturer:b

Model Number:d

Util. Component ID:

Event Date:a

In-Service Date:C

Age:e

Out-of-Service: YES/NO f

Out-of-Service (replacement) Date:

Safety Class:

CODE DESCRIPTION

FAILURE CAUSE

Supplemental Cause

Agree w/NPROS YES/NO

Aging YES/NO/UNK

COMPONENT

Subcomponent

FAILURE MODE: COMPONENT

Subcomponent

SECONDARY FAILURE MODE: COMPONENT

Subcomponent

SYSTEM .. System Initial Conditions

System Effect

INTERFACING SYSTEM _

METHOD OF DISCOVERY

UNIT: INITIAL CONDITIONS

Unit Effect

Testing Performed Frequency/Interval Hours 0OS

TESTING Check Testing

INTERVAL Functional Testing

Calibration Testing

Reference Reports:g

Pertinent Information:

Comments:

Failure Cause Key Phrases:

Figure B-I. Failure cause coding form.

B-4
EXPLANATION OF FOOTNOTES

a. Event Date (or date failure occurred)--The date or estimated date

that the system or component first became unable to operate at an

acceptable level.

b. Manufacturer--The company that manufactured the component.

c. In-Service Date--The actual date the system or component went

into service.

d. Model Number--The number used by the manufacturer to identify the

component.

e. Age--This is the time to failure based on elapsed time from

in-service date to event date.

f. Out-of-Service Date--(a) If the out-of-service date is given in

the NPRDS 2C-Component Engineering Report, use of this date as

the out-of-service date shows the date that the old component was

replaced with an identical component, or equivalent. (b) If no

out-of-service date is given in the 2C report, use the Event

Date (EDATE) given in the 4C-Component Failure Report if there

was an indication that the component was repaired.

g. Reference Reports--If a Licensee Event Report (LER) was

indicated, used the actual LER number. If the record stated that

an LER was submitted, the analyst stated ULER submitted.' Also,

utility document numbers concerning analysis of a failure were

recorded.

Figure B-1 (continued)

1B-5
Table B-1. Cross-reference fields between the NPRDS records and the failure cause

coding form

NPRDS

Report Field Failure Cause Coding Form Field

2C-Component Engineering Report

UNITID

SYSTEM

UTILITY COMPONENT ID

NSSS

ISDATEd

OSDATEd

SCLASSd

MFGd

MFG MODEL NOd

CTFREQd

CTHRSd

FFREGd

FCODfd

FHRSu

CALFREQd

CALCODEd

CALHRSd

Plant Identificationa

Docket Number

Report Type

Report Numberb

Plant Groupb

Systemb

Utility Component Identificationb

Plant Typec

Age

In-Service Date

Out-Of-Service Date (if specified)

Safety Class

Manufacturer

Model Number

Check-Testing Frequency

Check-Testing Out-Of-Service Hours

Functional Testing Frequency

Functional Testing Interval Code

Functional Testing Out-of-Service Hours

Calibration Testing Frequency

Calibration Testing Interval Code

Calibration Testing Out-Of-Service Hours

Event Dateb

System Initial Conditionsd

Method of Discovery

Method of Discovery

Failure Mode-Component

Reference Reports

Root Cause

Root Cause

System Effectd

Unit Effectd

Subcomponent

Root Cause

Root Cause Key Phrases

Comments

4C-Component Failure Report SDATEd

STATUSd

DETECTd

FAILURE DESCRIPTION

CAUSE CAT

CAUSE

SYS EFFd

PL EFFd

CAUSE OF FAILURE

CORRECTIVE ACTION

a. Plant ID is the fourth to seventh digit from UNITID field.

b. Necessary fields to retrieve NPRDS record.

c. Plant group: A - B&W for PWRs and C - GE for BWRs.

d. Taken directly from the NPRDS records.

B-6
assigned one of three aging classifications: non-1\

aging, conditional aging, or aging. Aging-related~l

failure cause codes are codes that always relate to

time-dependent effects. Examples of these timedependent codes are "erosion," "corrosion," and

"wear." Non-aging-related failure cause codes are

used for random events that cause immediate failure of the component. Examples of these types of

failure causes are "fire/smoke," "impact loads,"

and "electromagnetic interference." Conditional

aging failures are classified as aging-related if information in the failure report indicates some agingrelated effect code (from the categorization

scheme) or some keyword that indicates that a timedependent process is present. A failure categorized

with a conditional aging code is classified nonaging if the failure description indicates that a random event caused an immediate failure. In some

instances, a failure description contains enough

information to allow categorization with a conditional code but gives no indication as to whether

the failure was random or aging-related in nature.

In this latter case, the failure will be assigned an

"unknown" classification.

Table B-2 presents the failure cause categorization and aging classification scheme. It is followed

by the aefinitions of the failure causes and guidelines for establishing the aging classification.

Table B-2. Failure cause categorization and aging classification scheme

D Design/manufacturing/construction/quality assurance inadequacy

DC Construction error or inadequacy - conditional aging-related

DCI Initial construction activity

DCR Retrofit construction activity

DE Design error or inadequacy - conditional aging-related

DEI Initial design activity

DER Retrofit design activity

DM Manufacturing error or inadequacy - conditional aging-related

DQ Quality assurance error or inadequacy - non-aging-related

DQD Initial design quality assurance activity

DQE Retrofit design quality assurance activity

DQI Initial construction quality assurance activity

DQM Manufacturer quality assurance activity

DQR Retrofit construction quality assurance activity

DR Plant definition requirements inadequacy - conditional aging-related

DRI Initial definition activity

DRR Retrofit definition activity

B-7
Table B-2. (continued)

E Environmental stress

EA Animate causes

EAB Metal-sheathed bacteria - aging-related

EAE Animal encroachment - conditional aging-related

EAO Aquatic organisms - conditional aging-related

EB Materials interaction

EBB Embrittlement - aging-related

EBC Cavitation - conditional aging-related

EBE Erosion - aging-related

EBF Cyclic fatigue - aging-related

EBM Materials defect - conditional aging-related

EBR Wear - aging-related

EBS Steam impingement - non-aging-related

EBW Weld-related flaw - conditional aging-related

EC Chemical reactions

ECC Corrosion - aging-related

ECE Electrolysis - aging-related

ECF Foaming - non-aging-related

ECS Stratification - conditional aging-related

ED Mechanical failure

EDB Binding/out of adjustment - conditional aging-related

EDF Friction - non-aging-related

EDI Foreign materials intrusion - conditional aging-related

EDL Improper level - non-aging-related

EDO Mechanical overload - conditional aging-related

EDS Set point drift - aging-related

EDT Out of calibration - conditional aging-related

EDU Improper lubrication - conditional aging-related

EDW Improper flow - non-aging-related

B-8
Table B-2. (continued)

EE Electromagnetic interference - non-aging-related

EEI Inadvertent electrical energy exposure

EEM Magnetic field exposure

EEN Noise

EF Fire/smoke - non-aging-related

EH Human-caused event - non-aging-related

EHD Deliberate acts

EHU Unintentional acts

EI Impact loads - non-aging-related

EL Electrical failure

ELA Arcing - conditional aging-related

ELC Over/under current - conditional aging-related

ELD Set point drift - aging-related

ELE Electrical overload - conditional aging-related

ELF Faulty module - conditional aging-related

ELG Abnormal specific gravity - conditional aging-related

ELH Abnormal resistance - aging-related

ELI Insulation breakdown - conditional aging-related

ELK Contact failure - conditional aging-related

ELL End of life - aging-related

ELO Open circuit - conditional aging-related

ELR Erroneous/spurious signal - non-aging-related

ELS Short circuit - conditional aging-related

ELT Out of calibration - conditional aging-related

ELV Over/under voltage - conditional aging-related

ELW Winding/coil failure - conditional aging-related

EM Moisture

EMH High humidity - conditional aging-related

EMI Icing - non-aging-related

B-9
Table B-2. (continued)

EML Low humidity - non-aging-related

EMW Water intrusion - conditional aging-related

EN Acts of nature

ENA Atmospheric conditions - conditional aging-related

ENG Geological/geographic conditions - non-aging-related

ENM Meteorological conditions - non-aging-related

EP Pressure - non-aging-related

EPF Fluctuating pressure

EPH High pressure

EPI Improper differential pressure

EPL Low pressure

ER Radiation - aging-related

ERH High-level radiation

ERL Low-level radiation

ET Temperature - conditional aging-related

ETF Fluctuating temperature

ETH High temperature

ETI Improper differential temperature

ETL Low temperature

EV Vibration loads - conditional aging-related

EVF Flow-induced vibration

EVM Mechanical vibration

H Human actions

HA Accidental action - non-aging-related

HAC Calibration activity

HAM Maintenance activity

HAO Operations activity

HAQ Quality assurance activity

HAT Testing/surveillance activity

B-10
Table B-2. (continued)

HC Communication problem - non-aging-related

HCC Calibration activity

HCM Maintenance activity

HCO Operations activity

HCQ Quality assurance activity

HCT Testing/surveillance activity

HE Human error (practices) - conditional aging-related

HEC Calibration activity

HEM Maintenance activity

HEO Operations activity

HEQ Quality assurance activity

HET Testing/surveillance activity

HM Misdiagnosis - conditional aging-related

HMC Calibration activity

HMM Maintenance activity

HMO Operations activity

HMQ Quality assurance activity

HMT Testing/surveillance activity

HP Failure to follow procedures - conditional aging-related

HPC Calibration activity

HPM Maintenance activity

HPO Operations activity

HPQ Quality assurance activity

HPT Testing/surveillance activity

S Supervision/management inadequacy

SC Contractor/other personnel inadequacy - non-aging-related

SH Inadequate human environment (hazardous) - non-aging-related

SHC Calibration activity

SHM Maintenance activity

B-I I
Table B-2. (continued)

SHO Operations activity

SHQ Quality assurance activity

SHT Testing/surveillance activity

SP Procedures inadequacy - conditional aging-related

SPC Calibration procedures

SPM Maintenance procedures

SPO Operational procedures

SPQ Quality assurance procedures

SPT Testing/surveillance procedures

ST Training inadequacy - conditional aging-related

STC Calibration activity

STM Maintenance activity

STO Operations activity

STQ Quality assurance activity

ST-F Testing/surveillance activity

U Unclassifiable cause - conditional aging-related

UA Aging/wearout - aging-related

UE Effects displayed - conditional aging-related

UEB Burned out

UEC Closed

UEE Bent/overstressed

UEF Computer malfunction

UEK Broken

UEL Leakage

UEM Missing/misplaced

UEO Open

UES Loose

UET Tight

UN No effects displayed - conditional aging-related

B-12
Definitions

The definitions for each of the entries in the failure cause categorization scheme are presented in

this section.

D Design/Manufacturing/Construction/Quality

Assurance Inadequacy

This is the group of causes associated with

decisions or events that generally take place

before the plant is operational. These causes

are usually outside the purview of operations

personnel.

DC Construction Error or Inadequacy

The DC code is used when the constructors do not follow instructions, abuse

equipment, or use poor practices in

matters normally left to the judgment

of the installers.

Aging Classification: Conditional

aging - Errors or inadequacies associated with these causes can cause accelerated aging. In order for a failure to be

classified as aging-related when using

one of these codes, the failure description must also contain an aging-related

environmental stress effect or failure

cause (described under the environmental codes) resulting from the error or

inadequacy.

DCI Initial Construction Activity

DCR Retrofit Construction Activity

DE Design Error or Inadequacy

This code is applied where the designer

uses a wrong table or equation, errs in

making a calculation, allows inadequate margin, misapplies equipment,

or fails to provide error-free drawings

and specifications to manufacturing.

Aging Classification: Conditional

aging - Errors or inadequacies associated with these causes can cause accelerated aging. In order for a failure to be

classified as aging-related when using

one of these codes, the failure description must also contain an aging-related

environmental stress effect or failure

cause (described under the environmental codes) resulting from the error or

inadequacy.

DEI Initial Design Activity

DER Retrofit Design Activity

DM Manufacturing Error or Inadequacy

The DM code is applied when manufacturing personnel do not follow the

designer's instructions, allow manufacturing processes to go out of control, or

allow damage to occur to the manufactured items while in storage.

Aging Classification: Conditional

aging - Errors or inadequacies associated w hese causes can cause accelerated a in In order for a failure to e

classified as aging-related when using

one of these codes, the failure description must also contain an aging-related

environmental stress effect or failure

cause (described under the environmental codes) resulting from the error or

inadequacy.

DQ Quality Assurance Error or Inadequacy

This code is applied when design, construction, or manufacturing personnel

do not properly perform quality assurance on this work.

Aging Classification: Non-aging - failures resulting from accelerated aging

caused by design, construction, or manufacturing activities would be coded

under those failure codes, not quality

assurance codes.

DQD Initial Design Quality Assurance

Activity

DQE Retrofit Design Quality Assurance Activity

DQI Initial Construction Quality

Assurance Activity

B-13
DQM Manufacturer Quality Assurance

Activity

DQR Retrofit Construction Quality

Assurance Activity

DR Plant Definition Requirements Inadequacy

This is the most basic design-related

inadequacy-the failure to provide the

proper set of design requirements for

the component. For example, the design

requirements call for an ambient temperature of 1000F, whereas the actual

temperature frequently exceeds 1 15'F.

Aging Classification: Conditional

aging - Inadequacies associated with

these causes can cause accelerated

aging. In order for a failure to be classified as aging-related when using one of

these codes, the failure description must

also contain an aging-related environmental stress effect or failure cause

(described under the environmental

codes) resulting from the inadequacy.

DRI Initial Definition Activity

DRR Retrofit Definition Activity

EA Animate Causes

This cause code relates to failures

involving nonhuman animate causes.

EAB Metal Sheathed Bacteria

This cause code refers to growth

of bacteria that attack pipe

walls.

Aging classification: Aging -

The process of bacterial attack

on piping walls results in a degradation that is time-dependent.

EAE Animal Encroachment

Code refers to invasion by animals, such as rats, field mice,

and birds.

Aging Classification: Conditional aging - The occurrence of

animal encroachment is not generally considered aging-related,

since the action would result in

an immediate equipment failure

particularly in items such as electrical cabinets. The gradual

accumulation of animal debris,

causing degradation of electrical

equipment in a panel, is considered to be aging-related.

E Environmental Stress EAO Aquatic Organisms

The following cause codes represent actual

causes of failures. In many cases, the codes

stand for the effects produced by mechanisms

that may not be identified by the failure

descriptions. Therefore, for the purpose of categorization, the terms "effect" and "cause"

can be used interchangeably. These cause codes

apply to environmental stresses that may be

either the sole cause or one of two or more

causes that together are the cause of a component failure. Generally, an abnormal stress may

be a sole cause, whereas an ambient stress usually acts in conjunction with another cause.

With the exception of the "acts of nature" and

"human caused events," the stresses are considered to be induced by the plant environment.

This includes invasion by

aquatic organisms such as fish

and snails.

Aging Classification: Conditional aging - In general, failures

resulting from the intrusion of

aquatic animals are not considered aging-related. However,

buildup of organisms such as

algae, etc.; constitute a timedependent process and as such

are considered aging-related.

Failures resulting from the latter

would normally contain indications of foreign material intrusion, and gradual accumulation,

in the failure description.

B-14
EB Materials Interaction

This category includes causes arising

from the interaction or interfacing of

materials in components, between components, or between solids and liquids.

EBB Embrittlement

The EBB code represents a materials problem brought about by

the environment a component is

in, such as high-temperature

effects on seals or high-level

radiation exposure. Embrittlement may lead to cracking.

Aging Classification: Aging -

Embrittlement is a timedependent degradation of material properties.

EBC Cavitation

nent are gradually diminished.

These processes are caused by a

flowing medium, such as a liquid, gas, or slurry, impinging on

the component.

Aging Classification: Aging -

Erosion is the time-dependent

removal of material by some

active agent.

EBF Cyclic Fatigue

This is a failure cause in metals

and some plastics where

repeated or cyclic loading yields

cracking or fracture.

Aging Classification: Aging -

Cyclic fatigue is a timedependent degradation of material properties.

EBM Materials Defect

Cavitation is a hydraulic phenomenon of a liquid changing

into a gaseous phase in a region

of low liquid pressure. The

vapor bubbles can later collapse,

causing shock waves and damage to chamber walls.

Aging Classification: Conditional aging - Cavitation results

from system conditions resulting

from random events, poor

design, or misapplication of

hydraulic equipment. Cavitation

will generally produce an immediate degradation of the system

or equipment such as pumps. In

this situation, cavitation is considered non-aging. The code is

considered to be aging-related if

the cavitation has caused erosion, such as in thinning of pipe

walls or pitting and eroding

pump impellers.

Erosion

This cause code includes pores

and voids.

Aging Classification: Conditional aging - Defective or weakened materials can result in the

effective accelerated aging of a

component operating in its

design environment. In this situation, the cause (or effect) is

classified as aging. Material

defects can also cause component failure once placed in operation. In the latter situation, the

code is not considered aging

because an immediate failure

occurs.

EBR Wear

This refers to the process of relative movement between parts of

a component gradually deteriorating the contact surfaces. The

EBR code includes abrasion,

galling, and fretting.

Aging Classification: Aging -

Degradation from this cause (or

EBE

Erosion refers to processes

where the surfaces of a compoB-15
effect) is time-dependent in nature.

EBS Steam Impingement

This cause code refers to high

temperature and high humidity

events.

Aging Classification: Nonaging - This cause (or effect)

refers to immediate failure due

to a random event causing high

temperature or humidity.

EBW Weld Related Flaw

The EBW code includes any

materials problems, such as

cracking, which occur in welds

or in the heat-affected zone.

Aging Classification: Conditional aging - Defective or weakened welds can result in the

effective accelerated aging of a

component operating in its

design environment. In this situation, the cause (or effect) is

classified as aging. Weld defects

can also cause component failure when first placed in operation. In the latter situation, the

code is not considered aging

because the failure will be immediate.

EC Chemical Reactions

This cause code applies to chemical

reactions between the component and

chemicals in the process or in the environment that cause corrosion, foaming,

or electrolysis.

ECC Corrosion

This cause has several forms:

corrosive agent exposure, galvanic corrosion, oxidation corrosion, stress corrosion/

intergranular stress corrosion

cracking (IGSCC).

Aging Classification: Aging -

All forms of corrosion entail the

time-dependent degradation by

some agent.

ECE Electrolysis

The ECE code refers to the

decomposition of a substance by

electric current.

Aging Classification: Aging -

The decomposition of a substance through electrolysis is a

time-dependent process. Therefore, any failures attributable to

this cause are considered agingrelated.

ECF Foaming

This code refers to a frothing

that is caused by chemical impurities.

Aging Classification: Nonaging - Chemical impurities

entering a system in concentrations high enough to cause frothing would result in the

immediate degradation of the

system or component performance.

ECS Stratification

The ECS code refers to a condition where a formerly mixed

chemical substance separates

and forms layers of constituent

elements.

Aging Classification: Conditional aging - Stratification of

chemicals is a time-dependent

process usually occurring in

battery chemicals. Particularly

in the case of battery power degradation, the cause (or effect) is

considered to be aging. This

code is considered to be conditional aging so as not to preclude immediate performance

B-16
degradations in other systems

where chemicals are mixed.

classification is assigned to the

cause of the friction.

ED Mechanical Failures EDI Foreign Materials Intrusion

This cause category applies to all failures found in mechanisms, machines,

and mechanical devices. This includes

valve operators and circuit breaker

mechanisms.

EDB Binding/Out of Adjustment

This applies mainly to shafts,

but can be used for other failures

as well. It should not be used for

a component that is out of calibration.

Aging Classification: Conditional aging - Binding/out of

adjustment due to a maintenance activity or thermal stress

on the system usually results in

the immediate failure of the

component and is considered to

be non-aging. However, cases

occur where the problem is not

serious enough to cause immediate failure. In this situation,

accelerated aging can occur. The

failure would be classified aging

only if information exists in the

failure description linking an

aging failure cause (or effect)

with the binding/out of adjustment condition.

EDF Friction

The EDF code is mainly

intended to describe the process

where heat is produced by excessive contact of moving parts; but

it can have other applications,

such as flow friction.

Aging Classification: Nonaging - This code is primarily an

effect code resulting from items

such as loss of or improper lubrication, binding/out of adjustment, etc. Therefore, the aging

This code includes blockage/

obstruction, dirt, and particulate contamination.

Aging Classification: Conditional aging - Situations where

equipment failures occur due to

the build up of some material

resulting from the action of a

time-dependent agent are classified as aging. Blockages due to

random events are non-aging.

EDL Improper Level

The EDL cause code includes

high/low level and fluctuating

level.

Aging Classification: Nonaging - This code represents an

immediately detectable system

condition due to an event consisting of either a random or

aging-related failure of some

component. The aging classification would be assigned to the

failure cause of the component.

This code should not be used for

lubrication incidents.

EDO Mechanical Overload

The EDO code refers to force or

stress greater than design capabilities, either demanded or

received from a machine or

mechanism.

Aging Classification: Conditional aging - In general, this

cause (or effect) applies to events

where an overload condition

caused by some other event leads

to an immediate failure. Since

the continual application of

overload conditions will lead to

degradation of equipment, the

cause (or effect) is considered to

B-17
be aging-related if the failure

description indicates that the

condition has existed for some

period of time.

EDS Set Point Drift

This cause code refers to

mechanical set points that

change over time, such as spring

tension in relief valves.

Aging Classification: Aging -

The drift of mechanical set

points requires the timedependent change of material

properties.

EDT Out of Calibration

The EDT cause code refers to

mechanical items that fall out of

calibration and do not perform

as required. This code should

only be used when no better

information is available. For

example: cable drive slips on a

strip-chart recorder so the pen

does not mark at the true indication. "Zero adjustment" faults

are also included here.

Aging Classification: Conditional aging - This cause (or

effect) code may be the result of

random actions that disturb the

equipment. A common example

would be maintenance errors.

This code is analogous to drift

when a time-dependent aging

phenomenon is involved. In

order for this code to be classified as aging, some indication of

a time dependence must be

present in the failure description.

EDU Improper Lubrication

This cause code applies to lossof-lubrication incidents. Other

lubrication problems should be

covered by personnel codes.

Aging Classification: Conditional aging - Improper lubrication can cause accelerated aging

when not detected. To classify a

failure, using this code, as aging,

there must be an aging effect

code identifiable in the failure

description.

EDW Improper Flow

The EDW cause code includes

high/low flow, no flow, and pulsating flow.

Aging Classification: Nonaging - This code represents an

immediately detectable system

condition due to either a random

or aging-related failure of some

component. The aging classification would be assigned to the

failure cause of the component.

EE Electromagnetic Interference

This cause code applies to all electromagnetic interferences generated by

equipment in dr around the plant. It

does not include lightning, an "act of

nature."

Aging Classification: Non-aging - Electrical failures resulting from these

causes (or effects) are considered to be

random.

EEI Inadvertent Electrical Energy

Exposure

The EEI code includes static

charge buildup.

EEM Magnetic Field Exposure

This cause code includes magnetization of ferritic components.

EEN Noise

Noise is the generation of random electrical impulses that are

transmitted with signals.

B-18
EF Fire/Smoke

This cause code applies to fire or any

form of combustion. This stress may be

due to heat or the combustion products.

This could be inside or outside the

plant.

Aging Classification: Non-aging - Fires

result in immediate degradation of

equipment performance.

EH Human Caused Event

This code refers to human actions that

are outside normal operation of the

plant (i.e., the personnel involved, if

they are plant employees, caused a failure doing something other than the performance of their jobs). Nonplant

personnel may be antagonistic and/or

violent.

Aging Classification: Non-aging - Failures resulting from human actions are

random events.

EHD Deliberate Acts

This code includes malicious

mischief.

EHU UnintentionalActs

The EHU code includes transportation accidents and industrial accidents.

El Impact Loads

This cause code applies to impact loads

imposed on a component. Examples are

component damage by a falling body or

distortion of a check valve caused by

water hammer. These could affect the

component either internally or externally.

Aging Classification: Non-aging - Failures resulting from impacts are random

events. Events such as water hammer

are precluded by operational procedures. Should continuing water hammer events degrade a system, the failure

would be classified aging under a procedural cause code.

EL Electrical Failure

This cause code is used for electrical

items where more detailed information

is not obtainable. These causes interfere

with the function of electrical components.

ELA Arcing

Arcing is a condition of electric

current breaking down air and

spanning a gap between open

contacts.

Aging Classification: Conditional aging - In general, this

cause (or effect) would result in

immediate failure of the electrical component. However, in the

case of c

_!n.via multiple switch or relay

opening and closure, the cause

would be considered aging.

ELC Over/Under Current

This code refers to a condition of

too high or too low current.

Aging Classification: Conditional aging - In general, this

cause (or effect) applies to events

where over/under current conditions caused by some other event

lead to an immediate failure.

Since the continual application

of over/under current conditions will lead to degradation of

eguiwnentj the cause (or effect)

is considered to be aging-related

if the failure description indicates that the condition has

existed for some period of time,

such as longer than a mainteELD Set Point Drift

This code refers to electrical

equipment varying from a fixed

B-19
setting for starting a process,

stopping a process, or modifying

a process.

Aging Classification: Aging -

Set point drift of electrical components requires the timedependent degradation of the

material electrical properties.

ELE Electrical Overload

The ELE code refers to more

power demanded or delivered

than the component is designed

for.

Aging Classification: Conditional aging - In general, this

cause (or effect) applies to events

where an overload condition

caused by some other event leads

to an immediate failure. Since

the continual application of

overload conditions will lead to

degradation of equipment, the

cause (or effect) is considered to

be aging-related if the failure

description indicates that the

condition has existed for some

period of time, such as longer

than a maintenance interval.

ELF Faulty Module

Faulty module refers to a condition where an electrical unit

composed of more than one

solid-state component (such as

an amplifier, circuit board, integrated circuit, etc.) does not perform its function. The cause for

failure to perform is likely to be

undetermined.

Aging Classification: Conditional aging - In general, the

cause will be aging-related

because a component in the

module failed due to continued

operation at stressful conditions, such as abnormal temperature, excessive vibration, or

electrical overload. Some cases

will exist where the failure is due

to mishandling or a single event;

in those cases, the failure is nonaging.

ELG Abnormal Specific Gravity

Abnormal specific gravity refers

to a condition of the electrolyte

in a lead-acid storage battery.

Specific gravity is an indicator of

the charge of a battery. Low specific gravity indicates a low state

of charge. Abnormal specific

gravity is usually low, but some

situations can cause the measured specific gravity to be high.

Aging Classification: Conditional aging - When the failure

description indicates that the

abnormal specific gravity is

related to an aged battery that

can no longer be successfully

charged, the failure is agerelated. In some cases, the specific gravity will be low because

the battery had not been charged

or because water had been

recently added; the failure cause

is then non-age-related.

ELH Abnormal Resistance

Abnormal resistance refers to a

condition in which the resistance

is not as expected but is neither a

short circuit or an open circuit.

Windings, coils, and contacts in

switches, relays, or connectors

can have an abnormal resistance

that prevents proper operation.

Aging Classification: Agingrelated - Abnormal resistance is

caused by corrosion, insulation

breakdown, or other timerelated effects that either

increase or decrease the resistance of the circuit.

B-20
ELI Insulation Breakdown ELO Open Circuit

The ELI code refers to a

degraded condition of electrical

insulation that allows current to

seek a path through the insulation.

Aging Classification: Conditional aging - In general, the

cause (or effect) will be agingrelated since the decomposition 1

of insulation is a time-dependent

process. Cases will exist, however, where the insulation was

damaged by an random event,

such as impact. In the latter situELK Contact Failure

Contact failure refers to a condition of a relay when the failure is

known to be at the contact rather

than the coil but additional

information is not provided. The

event could be a failure of the

contact to close, to open, or to

make proper electrical contact

even though it mechanically

operated, such as would happen

with corroded contacts.

Aging Classification: Conditional aging - If the failure

description indicated the existence of time-related factors, the

failure is age-related. If the failure is caused by a single event,

such as over-current damaging

the contacts, the failure is nonage-related.

ELL End ofLife

End of life is a condition in

which the failure is attributed to

the component being old or having reached its natural end of life

without providing more detailed

information.

Aging Classification: Agingrelated - The stated condition is

end of life.

Open circuit is a condition where

the resistance between two conductors of a electrical circuit is

very large. Examples include

broken wires, wires coming loose

from terminals, connectors

becoming loose, and excessive

corrosion at connections.

Aging Classification: Conditional aging - In general, this

condition would result in immediate failure of the circuit to perform its intended function.

However, in the case of connections corroding or wires breaking due to continual flexing or

frequent handling, the cause

would be considered aging.

ELR Erroneous/Spurious Signal

The ELR code refers to a signal

that is unwanted or unneeded,

sometimes generated by electrical noise.

Aging Classification: Nonaging - This cause (or effect) is

considered a random event.

ELS Short Circuit

Short circuit refers to a condition is which the resistance

between two conductors or

between a conductor and ground

is very small and much less than

normal for that particular circuit.

Aging Classification: Conditional aging - Often this condition will be age-related, since

short circuits usually result from

is ie-en t rcess.

Cases will exist where the short

circuit is a result of damaged

insulation or some event that

causes a mechanical connection

(

B-21
of the two conductors. In the latter situation, the failure is nonaging-related.

ELT Out of Calibration

The ELT code refers to a component being out of calibration and

not performing as required.

Sending a signal at an incorrect

voltage is an example of out of

calibration.

Aging Classification: Conditional aging - This cause (or

effect) code may be the result of

random actions that disturb the

equipment. A common example

would be maintenance errors.

This code is analogous to drift

when a time-dependent aging

phenomenon is involved. In

order for this code to be classified as aging, some indication of

a time dependence must be

present in the failure description.

ELV Over/Under Voltage

This code refers to a condition of

too high or too low voltage.

Aging Classification: Conditional aging - In general, this

cause (or effect) applies to events

where over/under voltage conditions caused by some other event

lead to an immediate failure. But

since the continual application

of over/under voltage conditions will lead to degradation of

equipment, the cause (or effect)

is considered to be aging-related

if the failure description indicates that the condition has

existed for some period of time,

such as longer than a maintenance interval.

ELW WVinding/Coil Failure

Winding/coil failure is a condition in which a winding/coil in a

motor, solenoid, relay, switch,

etc. has failed (often burned out)

but the cause of the failure is not

defined. Causes could be a result

of a failure within the winding/

coil or a result of some adverse

condition that was applied.

Aging Classification: Conditional aging - Failures as a result

of insulation breakdown or continued operation at elevated temperature or in a high humidity

environment would be agingrelated. Failures as a result of a

single event would be non-agingrelated.

EM Moisture

This cause code is applied to ice, water,

or water vapor in the environment that

causes a component failure. Spray and

flood are two examples.

EMH High Humidity

The EMH code refers to high

humidity inside the power plant.

Aging Classification: Conditional aging - The presence of

moisture in high concentrations

has degrading effects on equipment and is addressed by equipment qualification standards. A

failure that can be categorized

using this code is classified as

aging-related if the failure

reports contain indications of

other aging-related effects, such

as corrosion.

EMI Icing

The EMI code refers to icing

inside the plant, such as in ice

condenser units.

Aging Classification: Nonaging - Icing of equipment will

result in the immediate failure of

the affected equipment.

B-22
EML Low Humidity

This refers to lower-than-normal

humidity inside the power plant.

Aging Classification: Nonaging - Equipment qualification

standards do not consider low

humidity a concern to component operational life.

EMW Water Intrusion

The EMW code refers to water

entering the plant from outside

or for water intruding from area

to area inside the plant.

Aging Classification: Conditional aging - In general, the

intrusion of water is a random

event and will cause immediate

equipment failure. Undetected

and uncorrected water intrusion

can cause accelerated aging. For

this situation, the failure

description must also identify

aging-related effects to be classified as aging.

EN Acts of Nature

This cause code applies very selectively

to those causes that are in no way

induced by the plant itself, such as

_.gxihaiiukcs, tornadoes, floods, lightning, and precipitation.

ENA Atmospheric Conditions

The ENA code is used for conditions that are more or less stable

and originate due to climate or

other location-dependent conditions. This includes high or low

barometric pressure, high or low

atmospheric temperature, and

saline atmosphere.

Aging Classification - Conditional aging - Equipment failures attributable to atmospheric

conditions would be considered

aging-related if other effect or

failure causes such as corrosion

or foreign materials intrusion

were present in the failure

description. These types of

effects could result from

atmospheric conditions, such as

high saline content or winds with

high dust content.

ENG Geological/Geographic Conditions

This includes avalanche,

landslide/mudslide, and seismic

activity.

Aging Classification - Nonaging - These types of conditions

or events result in immediate

equipment failure.

ENM Meteorological Conditions

This includes weather conditions, such as electrical storm,

high wind, hurricane, lightning,

tornado, tsunami, rain or freezing rain, hail, and snow.

Aging Classification - Nonaging - This code is used where

these types of conditions or

events result in immediate equipment failure.

EP Pressure

This code is applied to liquid and gas

system pressure problems. It does not

include barometric pressure (code

ENA).

Aging Classification: Non-aging - Plant

design and operations are established to

control pressure. Therefore, failures

related to pressure would result from

procedural or equipment failures.

Aging classification would be reserved

for the failures causing the pressure

transient.

EPF Fluctuating Pressure

EPH High Pressure

B-23
EPI Improper Differential Pressure

EPL Low Pressure

ER Radiation

This cause code applies to damage due

to radiation (i.e., alpha, beta, gamma,

neutrons, or combinations thereof).

Aging Classification: Aging - Material

property degradation due to radiation is

considered to be aging-related.

ERH High Level Radiation

ERL Low Level Radiation

ET Temperature

machinery causes the loosening of

screws within a circuit breaker.

Aging Classification: Conditional

aging - Vibration will cause accelerated

aging to occur. The categorization of a

failure using these codes is classified

aging if one of the aging effect codes,

such as cyclic fatigue or wear, can be

identified in the failure description.

Vibration would be considered nonaging if, for example, a pump were out

of adjustment and began vibrating to

the point that it destroyed itself or a

piece part of the pump very quickly.

EVF Flow Induced Vibration

EVM Mechanical Vibration

H Human Actions

The ET cause code applies to the stress

caused by abnormal temperatures

within the plant.

Aging Classification: Conditional

aging - Temperature effects can cause

embrittlement or other material degradation, such as loss of plasticity or degradation of electrical equipment.

Improper differential temperatures can

cause binding or wear so as to eventually degrade a component. These effects

are time-dependent, and failures

labeled with these codes are classified as

aging if the failure description identifies

the presence of aging-related effects.

ETF Fluctuating Temperature

ETH High Temperature

ETI Improper Differential Temperature

ETL Low Temperature

EV Vibration Loads

These are human errors of omission, commission, and accidental human actions committed

during plant operation and maintenance.

("Design inadequacies" and "procedure inadequacies" are of human origin also, but are

remote from the on-line decisions that must be

made by a plant operator.)

HA Accidental Action

The HA code is used when the human

action is purely accidental. For example, the plant operator is correctly following the appropriate calibration

procedure, but the screwdriver slips and

short-circuits the signal line.

Aging Classification: Non-aging -

These causes refer to immediate equipment failures resulting from accidental

actions.

HAC Calibration Activity

HAM Maintenance Activity

HAO Operations Activity

This cause code applies to vibrationinduced loads imposed on a component

from sources within the plant. For

example, vibration from rotating

HAQ Quality Assurance Activity

HAT Testing/Surveillance Activity

B-24
HC Communication Problem

This cause code is used when personnel

encounter a communication discrepancy or problem, either written (such as

ambiguous plant orders or memos) or

oral (such as poor telephone connections or noise). This code is not used for

difficulties with procedures.

Aging Classification: Non-aging -

These causes refer to immediate events

resulting from poor communications.

HCC Calibration Activity

HCM MaintenanceActivity

HCO Operations Activity

HCQ Quality Assurance Activity

HCT Testing/Surveillance Activity

HE Human Error

HM Misdiagnosis (Followed Wrong Procedures)

The HM cause code applies when plant

personnel, through misdiagnosis,

choose the wrong procedure to follow.

Aging Classification: Conditional

aging - Actions associated with these

causes can cause accelerated aging. In

order for a failure to be classified as

aging-related when using one of these

codes, the failure description must also

contain an aging-related environmental

stress effect or failure cause (described

under the environmental codes) resulting from the error.

HMC Calibration Activity

HMM Maintenance Activity

HMO OperationsActivity

HMQ Quality Assurance Activity

This HE code is used when personnel

perpetrate an error of commission by

exceeding an appropriate procedure.

An example is when an operator overtorques a valve when directed to close it.

These types of errors are usually termed

"good practice" errors.

Aging Classification: Conditional

aging - Actions associated with these

causes can cause accelerated aging. In

order for a failure to be classified as

aging-related when using one of these

codes, the failure description must also

contain an aging-related environmental

stress effect or failure cause (described

under the environmental codes) resulting from the error.

HEC Calibration Activity

HEM MaintenanceActivity

HEO Operations Activity

HEQ Quality Assurance Activity

HET Testing/Surveillance Activity

HMT Testing/Surveillance Activity

HP Failure to Follow Procedures

This HP code is used when the procedures are correct but plant personnel

fail to follow the procedures.

Aging Classification: Conditional

aging - Actions associated with these

causes can cause accelerated aging. In

order for a failure to be classified as

aging-related when using one of these

codes, the failure description must also

contain an aging-related environmental

stress effect or failure cause (described

under the environmental codes) resulting from the error.

HPC Calibration Activity

HPM MaintenanceActivity

HPO Operations Activity

HPQ Quality Assurance Activity

HPT Testing/Surveillance Activity

B-25
S Supervision/Management Inadequacy Inadequacy SP Procedures Inadequacy

This group of causes pertains to utility management. It includes failure areas of management or supervision. Management is

considered responsible for non-plant personnel

working within the plant. Inadequate procedures and inadequate training programs arise

from improper managerial control. It is considered an error in supervision to send personnel into a hazardous environment without

proper protective clothing.

SC Contractor/Other Personnel Activity

The SC code applies to contractors or

other non-plant personnel who are

working in the plant area, but are not

plant employees. This code is used for

errors such as a contractor inadvertently tripping a circuit breaker in the

work location or incorrectly performing

a function so as to cause a component

to fail.

Aging Classification: Non-aging - The

cause refers to immediate failures

resulting from human interaction.

This is the group of causes associated

with procedures, written or not, that are

the prescribed way of operating and

maintaining the equipment. Inadequate

procedures include ambiguous, incomplete, or erroneous procedures. An

ambiguous procedure is one that lacks

clarity, or one that can easily be misinterpreted. An incomplete procedure is

one that omits an important detail or

assumes the operator knows more than

is normally expected. An erroneous

procedure is one that, if followed

exactly, would lead to an undesirable

result.

Aging Classification: Conditional

aging - Inadequacies associated with

these causes can cause accelerated

aging. In order for a failure to be classified as aging-related when using one of

these codes, the failure description must

also contain an aging-related environmental stress effect or failure cause

(described under the environmental

codes) resulting from the inadequacy.

SPC Calibration Procedures

SH Inadequate Human Environment

The SH code is used when the working

environment is hazardous or extreme,

containing such factors as high heat,

excess noise, steam leakages, or high

radiation.

Aging Classification - Non-aging -

These causes refers to immediate failures resulting from human interaction

due to environmental stress.

SHC Calibration Activity

SHM Maintenance Activity

SHO Operations Activity

SHQ Quality Assurance Activity

SHT Testing/Surveillance Activity

The SPC code applies to procedures on when and how to check

for calibration error, and how to

recalibrate.

SPM Maintenance Procedures

This code applies to procedures

on when and how to maintain

the plant equipment. It includes

schedules and procedures for

preventative maintenance, as

well as procedures for repairing

failed equipment.

SPO Operational Procedures

The SPO code applies to procedures on how to operate the

plant, as well as procedures that

tell operators when and how to

start, stop, and make operating

adjustments in equipment.

B-26
SPQ Quality Assurance Procedures

SPQ applies to procedures on

how to check and ensure the

quality of plant equipment.

SPT Testing/Surveillance Procedures

SPT applies to procedures on

when and how to test plant

equipment and follow surveillance instructions.

ST Training Inadequacy

The ST cause codes are used to describe

personnel who fail to perform their

function properly because of poor or

improper training, or because of unfamiliarity with the power plant.

Aging Classification: Conditional

aging - Inadequacies associated with

these causes can cause accelerated

aging. In order for a failure to be classified as aging-related when using one of

these codes, the failure description must

also contain an aging-related environmental stress effect or failure cause

(described under the environmental

codes) resulting from the inadequacy.

STC Calibration Activity

STM Maintenance Activity

STO Operations Activity

STQ Quality Assurance Activity

STT Testing/Surveillance Activity

U Unclassif able Cause

This code should only be used as a last resort.

It is used when the cause is simply not stated

within the failure report. Often the effect is

stated, so the third level was generated to retain

and show the effect displayed by the component.

Aging Classification: Conditional aging - Failures categorized with these codes are considered to be conditional aging-related. If the

failure description indicates that an unidentifiable, time-dependent process has occurred, the

failure would be classified as "unclassifiable

aging/wearout." If the failure description indicates an unidentifiable random event or provides no indication of what caused the failure,

then the failure would be classified non-aging

or unknown and one of the UE codes would be

used.

UA Unclassifable Aging/Wearout

UE Effects Displayed

UEB Burned Out

The UEB cause code is used to

indicate a loss of function due to

adverse electrical energy exposure.

UEC Closed

UEE Bent

UEF Computer Malfunction

UEF covers computer-oriented

problems whose nature is not

well explained. Resolution down

to hardware or software faults

should be covered with the other

cause categories (hardware

faults-E codes, software

faults-D or S codes).

UEK Broken

UEL Leakage

This code is used for between

systems leakage (internal) and

for out-of-system leakage (external).

UEM Missing/Misplaced

UEO Open

UES Loose

UET Tight

UN No Effect Displayed

B-27
APPENDIX C

COMPONENT BOUNDARIES FOR THE

FAIWRE CAUSE IDENTIFICATION STUDY

C-l
APPENDIX C

COMPONENT BOUNDARIES FOR THE

FAILURE CAUSE IDENTIFICATION STUDY

This appendix describes the component boundaries used in the root cause identification study.

Examples of subcomponents and piece parts are

also given for each of the components.

Battery Chargers

Battery chargers are units composed of transformers and rectifiers. The transformer converts

the alternating current (AC) input voltage to a

lower AC voltage, and the rectifier converts alternating current to a direct current (DC) voltage

which is filtered. Protection electrical devices and

monitoring instrumentation also exist to ensure

adequate operation (no overcharging, for example). A cooling system is likely to be internal to the

battery charger as well. The boundary includes the

output breaker between the charger and the battery.

Piece Parts:

Transformer (with subcomponents)

Rectifiers (with subcomponents)

Circuit breaker (with subcomponents)

Protective electronics

Monitoring instrumentation

Wiring

Connectors

Switches

Filters

Cooling subsystem (fans, for example)

Buses

Buses are bars of conducting material, such as

copper or aluminum. These are generally located

inside switchgear cabinets. Connectors are used to

join cables to buses. The component boundary is

around the bar itself and the connectors. Cables are

considered separately. Circuit breakers or motor

starters that may have a direct mechanical connection are also considered separately.

Cables

Electrical cables consist of one or more conducting material(s), usually strands of copper or aluminum, surrounded by insulated materials. Multiple

conductors are individually insulated. Insulating

materials are generally rubber, asbestos, enamel

coatings, mineral oil impregnated paper, or various

plastics.

The boundary is around the cable perimeter. Terminals and connectors are considered separately.

Circuit Breakers

The component boundary is the breaker casing

itself, including the internals such as the mechanism that moves the contacts, power lead connectors, and circuitry (such as relays). The control

power and line power cables are not considered to

be part of the circuit breaker.

Piece Parts:

Arc suppressor

Bearing

Bushing

Cable

Casing

Circuit board

Coil

Connector

Contacts

Converter

Drive pawl

Fuse

Indicator

Lockout device

Latch

Motor

Plunger

Relays

Solenoid

Spring

Switch

C-3
Emergency Diesel Generators Fuel System

The boundary for emergency diesel generators is

the diesel engine, generator, and associated subsystems. These subsystems include the lube oil system,

fuel system, starting air system, cooling system,

and engine exhaust system. The amount and type

of subcomponents are numerous. The output

power leads out of the generator, up to and including the output circuit breaker, are included in the

component boundary. The cooling systems include

heat exchangers that provide an interface to the

essential service water system, but not the piping

associated with the service water.

It should be noted that several types of valves,

such as gate or globe valves, may appear in failure

reports as part of emergency diesel generator subsystems. This will be treated as a subcomponent of

the diesel generator system, and the failure of the

diesel generator will be reported.

Components:

Principal System

Cables

Circuit breakers

Diesel engines (with associated components

and piece parts)

Generator (with associated components and

piece parts)

Governors

Instrumentation and control circuits

Relays

Switches

Voltage regulator

Filters

Gaskets

Motors

Pipes, supports, hangers

Pumps

Tanks

Valves and valve operators

Starting Air System

Air tank

Compressors

Filters

Gaskets

Piping, supports, hangers

Valves and valve operators

Cooling Systems

Heat exchangers

Heaters

Motors

Piping, supports, hangers

Pumps

Valves and valve operators

Tanks

Indicators (level, temperature,

pressure)

Engine Exhaust System

Piping

Baffles

Gaskets

Covers

Filter/Strainer

Lube Oil System

Filters

Gaskets

Heat exchangers

Heaters

Motors

Pipes, supports, hangers

Pumps

Valves and valve operators

Dip stick

A filter is a device containing a porous material

through which fluid is passed to remove suspended

impurities or to recover solids. The filter resides in a

housing, which holds and supports the filter material and also provides a pressure boundary.

Filters range in complexity from a filter material

in a housing to self-cleaning or traveling screens.

The boundary for the self-cleaning type includes

spray nozzles, refuse troughs, a pump, motor, and

sometimes a space heater to ensure continuous

operation during subfreezing temperature conditions. The boundary for the simple filter encloses

the housing and the filter material.

C-4
Filter/Strainer (continued) Measurement Systema

Piece Parts:

Filter material

Housing

Vent valves

Drain valves

Pump

Motor

Refuse troughs

Spray nozzles

Space heater

Piping from pump to nozzle

Inverters

Inverters convert DC power into AC power suitable for use for instrumentation. The boundary

around the inverter encloses the casing but stops at

the input and output leads. An inverter is sometimes referred to as an uninterruptible power supply.

A measurement system or subsystem consists of

one or more measurement devices and any other

necessary subsystem elements interconnected to

perform a complete measurement from the sensor

to the output. A measurement subsystem is divided

into general functional groups consisting of primary detector, intermediate means, and the end

device. The definitions of these functional groups

are as follows:

Primary Detector (sensing element or initial

element)-The primary detector is the first subsystem element or group of elements that

responds quantitatively to the parameter being

measured and performs the initial measurement

operation.

Intermediate Means-The intermediate means

includes all subsystem elements that are used to

perform necessary and distinct operations in the

measurement sequence between the primary

detector and the end device. It adapts the operational results of the primary detector to the input

requirements of the end device.

Piece Parts:

Annunciator control card

Capacitor

Choke

Control card/module

Cooling fan

Diode

Driver board

Firing circuit

Frequency board

Fuse

Inductor

Internal power supply

Oscillator

Protection card

Rectifier

Relay

Resister

Switch

Transformer

Transistor

Undervoltage coil

Undervoltage trip

Voltage regulator

End Device-An end device is the final subsystem element that responds quantitatively to the

parameter being measured and performs the

final measurement operation. It performs the

final conversion of measurement energy to an

indication, record, or the initiation of control.

The components of the measurement subsystem

are:

Pressure indicator

Flow indicator

Temperature indicator

Pressure indicator control

Temperature indicator control

Level transmitter

Inverter

Position switch

Pressure switch

Level switch

Temperature switch

a. Strictly speaking, a measurement system is a purist concept.

In practice, it is altered to fit the conditions of the engineer. For

instance, root cause analysis deals with systems containing

mechanical subsystems and electrical subsystems. In this case, a measurement system is considered a subsystem.

C-5
Measurement System (continued) seals use extremely close gaps so a fluid film forms

and keeps leakage acceptably low.

Piece Parts (continued):

Pressure differential switch

Timer

Thermowella

Cable

Motor-Driven Pumps

For these pumps, the component boundary is

chosen to be the pump unit and the driver. The

pump unit description is the same as that for the

turbine driver. The pump motor driver boundary is

around the driver housing and shaft coupling.

Power failures are not considered. Some motordriven pumps may have a reducing gear for variable

speed of the pump shaft. This special coupling is

included within the boundary. Any lubrication systems are also included.

Piece Parts:

Electric motor with internals

Housing/stator

Stator windings

Rotor body

Rotor windings

Magnets

Bearings

Motor shaft

Coupling to pump unit

Pump unit

Casing/housing

Impeller

Shaft

Bearings

Seals (see information below)

Suction

Lubrication subsystem

Pump Seals

Packing Materials:

Asbestos

Carbon

Graphite

TFE (Tetrafluoroethylene compounds, i.e.

Teflons)

Glass fiber

Metals [aluminum, copper, or Babbitt (an

antifriction alloy of tin, copper and antimony)]

0 and T rings of various elastomers

Mechanical seals:

Generally these are fine tolerance metal parts.

Spring loaded rings or injection fluids may be

used.

Pipes

Pipes include the following:

Elbows

Tees

Junctions

Unions (flanged or welded connection)

Tubing

Pipes and extruded tubing are in this category.

The component boundary is the outer wall of the

pipe or tubing. A junction is viewed as a small

diameter pipe welded to the side of a larger diameter pipe. In this case, the weld is considered as part

of the junction. A union is a connection between

two similar diameter pipes, either a flanged and/or

welded connection.

Piece Parts:

Pump seal failures will generally be described in

pump reports; however, they can be considered separately. Some pumps have complicated seals. A seal

is defined as a material "packed" about a shaft (or

between metal parts by either compression or

mechanical action to hold it in place). Mechanical

a. A piece of material (e.g., pipe) that protrudes into the system

boundary and forms a pressure boundary of the system. The

function of the thermowell is to measure the temperature inside

the system boundary.

Pipes

Tubing

Rectifiers

Generally, a rectifier converts alternating current

to direct current. It is composed of diodes (usually

solid state but may be selenium or mercury valves)

that are connected to each other.

The boundary is around the rectifier casing.

C-6
Rectifiers (continued)

Piece Parts: Supports and Snubbers

Connectors

Casing

Cooling fan

Diodes

Relays

The boundary around a relay includes the casing,

coil, and contacts. Control or line power faults are

outside the boundary.

Piece Parts:

Solenoid coil

Contacts

Wires

Springs

Connectors

These complex devices are used to accommodate

thermal movement, hydraulic transient loads, and

seismic event loads in piping and components in

accordance with American Society of Mechanical

Engineers (ASME) code requirements. They

include constant supports (CS), variable spring

supports (VSS), mechanical snubbers (MS), and

hydraulic snubbers (HS). The boundary encompasses the attachment to the pipe or component,

the attachment to the beam or other appurtenances, all external auxiliary systems that support

the device, and the device per se. The piece parts

for these devices are shown in the following matrix

(Table C-1).

Table C-1. Supports and snubbers piece parts

Device

CS VSS

X

MS

X

HS

X

X

Housing/body/eylinder

Wiper

Turnbuckle

Reservoir

Rod/Hanger

Bleed Plug

Welded Attachment

Clamp

Steal Beam

Filter

Valve

Travel Scale

Spring

Nut

Washer

Plate

Piston

Pivot

Shaft

Bearing

Inertia Mass

Torque Trans. Drum

Cylinder End Plug

Telescoping Cylinder

Paddle

Head

X

X

X

X

X

X X

X

X

X

x

x

x

x

x

x

X

x

x

X

x

X

x

X

x

x

x

x

x

x

x

x

x

x

C-7
Transformers

The component boundary is the transformer casing itself, including the internals such as the core

and wire winding. Cables are not considered as part

of the boundary.

Piece Parts:

Bonnet

Cap

Disc

Disc guide

Packing

Seat

Spindle

Spring

Bushings

Casing (perhaps an oil bath, too)

Coil windings

Connectors

Core

(some transformers may have a cooling subsystem for an oil bath or cooling fans)

Over-Pressure Protection Valves

This category includes the following:

Code safety valves

Power-operated relief valves

Safety/relief valves

These are specific valves for safety applications.

Code safety valves are safety valves that meet the

requirements of the ASME Boiler and Pressure

Vessel Code. This type of valve uses spring pressure

to hold the valve disc shut against the system pressure. It is totally self-activated and is used for quick

relief of excessive system pressure. The component

boundary is around the valve surface. The welds

that join the valve base and outlet to the associated

pipes are included with the pipe component.

Power-operated relief valves (PORVs) are controlled either automatically or manually. These

valves generally have a pilot tube and solenoid

plunger to control the valve disc (closure member)

motion. The component boundary is treated the

same as that for a code safety valve, with the inclusion of the solenoid and plunger. Power leads are

outside the boundary.

A safety/relief valve is another type of pressure

relief valve. This valve, like the PORV, can be operated automatically or manually. The component

boundary is treated the same as above, with the

boundary over the valve surface and welds included

in the piping system.

Piece Parts:

Code Safety Valve

Adjusting screw

Base

Power-Operated Relief Valve

Body

Lever

Packing

Pilot valve disc

Pilot valve seat

Piston

Plunger

Solenoid or other operator

Spring

Switch

Valve disc

Valve seat

Safety/Relief Valve

Base

Compression screw

Disc

Drop lever

Lifting gear

Operator

Packing

Seat

Spindle

Spring

Yoke

Check Valves

Check valves are considered to be simpler than

air- or motor-operated valves. The check valve is

designed to permit only one-directional flow.

Piece Parts:

Valve body

Valve closure member

Hinge

Access panel

Bolts, seals

C-8
Motor-Operated Valves

The boundary around a motor-operated valve

includes the valve and the motor operator. The

valve is defined as the valve body, all internals, and

seals. The motor operator is defined as all components inside the motor housing that are necessary to

make the valve function correctly. The control

power and main power cables are outside the

boundary.

Valve Piece Parts:

Valve stem

Yoke

Packing

Packing follower

Bonnet

Closure member

Flange

Valve body

Bolts, nuts

Valve seat

Seals

Motor Operator Piece Parts:

Flange

Valve body

Bolts, nuts

Valve seat

Seals

Air Operator Piece Parts:

Actuator housing

Air chamber

Diaphragm

Spring

Actuator shaft, coupling

Bolts

Linkages

Pneumatic positioner unit with internals (this

unit is not generic to all valve operator

designs.)

Air flow control valve (solenoid operated).

Manual Valves

The boundary around a manual valve includes

the valve body and actuator. The valve body is

defined as including all internals and seals.

Electric motor with internals

Housing/stator

Stator windings

Rotor body

Magnets

Bearings

Motor shaft

Gears

Limit switch

Torque switch

Manual operator

Valve stem connection

Housing assembly

Air-Operated Valves

The air-operated valve boundary is similar to the

motor-operated valve boundary. The valve parts

are basically the same, however, the operator is different. Loss of air pressure to the operator is not

considered to be a valve or operator fault.

Valve Piece Parts:

Valve Piece Parts:

Valve stem

Valve stem connection

Yoke

Packing

Packing follower

Bonnet

Closure member

Flange

Valve body

Bolts, nuts

Valve seat

Seals

Mechanical stop

Welds

A weld is the joint between two pipes, formed by

either heat or pressure or both, as well as the use of

a filler material for the gap between pipes. For this

definition, the heat-affected zone in the pipe material is included with the weld.

Valve stem

Yoke

Packing

Packing follower

Bonnet

Closure member

Piece Parts:

Welds

Filler material

Heat-affected zone of piping or tubing

C-9
APPENDIX D

FAILURE MODE CODES AND DEFINITIONS

D-1
APPENDIX D

FAILURE MODE CODES AND DEFINITIONS

Table D-1. Failure mode codes

Component

Battery/Battery Charging Unit

Bus

Cable

Circuit Breaker

Diesel Generator

Filter/Strainer

Hanger/Snubber/Support

Instrumentation

Inverter

Motor

Pipe

Power Supply, Electric

Motor-Driven Pump

Turbine-Driven pump

Relay

Thermowell

Code

GLF

GLF

GLF

GFP

GSO

GFS

GFU

GNF

GLF

GPL

GLF

GFP

GEE

GLF

GFU

GRU

GPL

GLF

GFS

GFU

GEL

GFS

GFU

GEL

GFC

GFO

GSH

GFP

GLF

Description

Loss of function (no output)

Loss of function

Loss of function

Fails to operate

Opens (premature)

Fails to start

Fails to run

No failure (only used when diesel generator

is still operable despite subcomponent

failure)

Loss of function

Plugged

Loss of function

Fails to operate

Erroneous/erratic signal

Loss of function

Fails to run

Rupture

Plugged

Loss of function

Fails to start

Fails to run

External leakage

Fails to start

Fails to run

External leakage

Fails to close (normally open)

Fails to open (normally closed)

Short circuit

Fails to operate (energize)

Loss of function

D-3
Table D-1. (continued)

Component Code Description

Timer GLF Loss of function

Transformer GLF Loss of function

Valves (general) GFO

GFC

GEL

GFR

GOC

GPL

Check Valve GFO

GIL

GEL

Motor-Operated Valve GFO

GFC

GEL

GPL

GFR

GOC

Fails to open

Fails to close

External leakage

Fails to operate as required

Fails to open/fails to close

Plugged (fails to remain open)

Fails to open

Internal leakage (reverse leakage)

External leakage

Fails to open

Fails to close

External leakage

Plugged (fails to remain open)

Fails to operate as required

Fails to open/fails to close

Fails to open

Fails to close

External leakage

Plugged (fails to remain open)

Fails to operate as required

Fails to open/fails to close

Fails to open

Opens (premature)

Fails to close (reseat)

Fails to open

Fails to close

External leakage

Fails to operate as required

Fails to open/fails to close

Plugged (fails to remain open)

Pneumatic Valve GFO

GFC

GEL

GPL

GFR

GOC

Relief/Safety Valve GFO

GSO

GFC

Vent Valve GFO

GFC

GEL

GFR

GOC

GPL

D-4
Table D-2. Failure mode descriptions

Battery/Battery Charging Unit

1. Loss of function-This failure mode is the inability of the charging unit to perform its function to

specifications or the lack of specified output from the battery.

Bus

I. Loss of function-This failure mode is the inability of the bus to perform its intended function.

Cable

1. Loss of function-This failure mode is the inability of the cable to transmit the correct signals. An

example of this type of failure mode is insulation breakdown around the cable producing a short or

ground.

Circuit Breaker

1. Fails to operate-This failure mode describes the circuit breaker that does not function properly. It

can either fail to open or fail to close on demand.

2. Opens (Premature)-This failure mode is the opening of the circuit breaker prior to demand.

Diesel Generator

1. Fails to start-Fails to start encompasses diesel generator failures that resulted from the diesel

failing to start, failing to reach rated speed and voltage once a start sequence was initiated, and

failing to achieve expected loading (kW).

2. Fails to run-Failure to run mode is any failure of an operating diesel generator to supply power to

the emergency bus, given that the diesel generator had undergone a successful start. It also includes

the spurious stopping of the diesel generator and the inability of the diesel generator to continue to

run as demanded.

3. No failure-The diesel generator does not fail when the narrative states that the diesel generator is

still operable despite the failure of a subcomponent in one of the diesel generator's subsystems. An

example of this is when a cooling pump fails but a back-up pump is available for the diesel

generator involved.

Filter/Strainer

1. Loss of function-This is the inability of the filter/strainer to perform its intended function.

2. Plugged-This includes plugging of the filter/strainer.

Hanger/Snubber/Support

1. Loss of function-This is the failure of the component to provide the pipe with the necessary

support and it is the inability of a snubber to perform to seismic requirements.

Instrumentation

1. Fails to operate-This failure mode is the inability of the instrument to perform its function.

2. Erroneous/Erratic signal-Erroneous or erratic signals are produced by the instrument.

D-5
Table D-2. (continued)

Inverter

1. Loss of function-This is the failure of the inverter to perform its intended function to specified

requirements.

Motor

1. Fails to run-This failure mode is the inability of a motor to run as required.

Pipe

1. Rupture-Rupture of a pipe is a break in the pipe that can or does produce leakage of the

contained medium.

2. Plugged-Plugging of a pipe is a restriction of flow of the contained medium.

Power Supply, Electric

1. Loss of function-This is the failure of the power supply to provide the required amount of power

to the interfacing component.

Pump

I. Fails to start-This failure mode is used to describe faults involving pumps that did not start upon

demand or which started and only operated for a brief period of time before tripping off-line.

2. Fails to run-Fails to run indicates that an operating pump was automatically or manually tripped

off-line to prevent damage to the pump. It also includes pumps that fail to run to specifications.

3. External leakage-The leakage failure mode describes a fault in which the pump is operational, but

is removed from service because of excessive leakage of the pumped medium. A common example

of this mode is a packing leak.

Relay

I. Fails to close-Fails to close is the failure of a normally open relay to close upon demand.

2. Fails to open-Fails to open is the failure of a normally closed relay to open upon demand.

3. Short circuit-This failure mode describes short circuit of either a normally open or normally

closed relay. This may include the improper operations of the relay.

4. Fails to operate (energize)-This failure mode is the failure of the relay to operate due to lack of an

input signal.

Thermowell

1. Loss of function-This failure mode is the inability of the thermowell to perform its function. This

includes leaks around the thermowell.

Timer

1. Loss of function-This failure mode is the inability of the timer to perform its function.

D-6
Table D-2. (continued)

Transformer

I. Loss of function-This failure mode is the inability of the transformer to continue to function

properly.

Valve

I. Fails to open-Valve fails to open fully when demanded.

2. Fails to close-Valve fails to close fully when demanded. This includes safety/relief valves failing to

reseat.

3. External leakage-A leak or rupture of the valve that would allow the contained medium to escape

from the component boundary. The most common example of this mode is a flange leak.

4. Plugged (fails to remain open)-This failure mode refers to any event that would stop or limit flow

through a normally open valve. Valves that fail to open or valves that are either intentionally or

unintentionally closed by human action when required open are not considered plugged valves. Two

examples of a plugging event are (a) a valve disc that separates from the stem and falls into the

closed position and (b) the air supply to an air-operated valve fails, allowing the valve to drift

closed.

5. Fails to operate as required-The fails-to-operate-as-required mode is to be used whenever (a) a

valve fails to meet specific requirements such as stroke time or (b) a valve loses the ability to

control system parameters.

6. Fails to open/fails to close-This failure mode is used when the narrative lacks specific information

on whether the valve failed to open or failed to close.

7. Internal leakage (reverse leakage)-Reverse leakage is a mode used to describe internal leakage

through a check valve.

8. Opens (premature)-This failure mode applies strictly to relief and safety valves. A relief or safety

valve opening prior to its pressure setting is a typical example of this mode; however, the cause of a

"premature open" is not always a pressure transient.

D-7
APPENDIX E

AGING FAILURE SURVEY INFORMATION

E-1
APPENDIX E

AGING FAILURE SURVEY INFORMATION

Appendix E is divided into nine subsections.

These subsections contain information pertinent to

the nine systems analyzed and appear in the following order:

1. Class 1E electrical power distribution system (IE)

2. Auxiliary feedwater system (AFW)

3. Component cooling water system (CCW)

4. High-pressure injection system (HPIS)

5. Main feedwater system (MFW)

6. Reactor protection trip system (RPS)

7. Residual heat removal system (RHR)

8. Service water system (SWS)

9. Standby liquid control system (SBL).

The following tabular information is provided for

each subsection:

I. A listing of the NSSS, system, and component codes and descriptions present in the

data for that specific system. This listing is

provided for ease of interpreting the codes

used in the tables.

2. A table summarizing the total counts per

failure category and total counts per system effect category with the corresponding

overall fractions per category. These failure fractions were calculated by dividing

the total counts within a failure category or

system effect category by the total failure

counts for that system.

3. A summary table indicating the total

counts for the major component divisions

and the corresponding fractions for the

five major failure categories. These

component/failure-category fractions

were calculated by dividing the total failure

counts per component/failure-category by

the total failure counts per component

within the appropriate system.

4. Detailed aging tallies tables (on microfiche

inside back cover). These tables display the

detailed breakdown for the data by component, system effect, failure category,

and age of component at time of failure.

The information is presented in these

tables by NSSS, system or subsystem, and

component. For each NSSS/system/

component combination, a failure total

and system effect breakdown is enumerated. The failure total indicates the total

failure counts for that particular NSSS/

system/component combination. The system effect number (sys. eff. no.) indicates

the total number of failures for that NSSS/

system/component that resulted in that

system effect.

E-3
Table E-1. Class 1 E electrical power distribution system

NSSS: A-BABCOCK & WILCOX

C-GENERAL ELECTRIC

E-WESTINGHOUSE

SYSTEM: A-BABCOCK & WILCOX

EBE-PLANT AC POWER

EBG-INSTRUMENT AC POWER

ECD-DC POWER

EEC-EMERGENCY POWER

EECDAA-DIESEL STARTING AIR

EECDCA-DIESEL COOLING WATER

EECFOA-DIESEL FUEL OIL

EECLOA-DIESEL LUBE OIL

C-GENERAL ELECTRIC

EBA-PLANT AC DISTRIBUTION

EBJ-INSTRUMENT AC POWER

ECB-DC POWER

EEA-EMERGENCY POWER

EEADAA-DIESEL STARTING AIR

EEADCA-DIESEL COOLING WATER

EEAFOA-DIESEL FUEL OIL

EEALOA-DIESEL LUBE OIL

E-WESTINGHOUSE

EBF-PLANT AC POWER

EBK-INSTRUMENT AC POWER

ECC-DC POWER

EEB-EMERGENCY POWER

EEBDAA-DIESEL STARTING AIR

EEBDCA-DIESEL COOLING WATER

EEBLOA-DIESEL LUBE OIL

COMPONENTS: ACCUMU INDREC

AIRDRY INTCPM

ANNUNC IPWSUP

BATTRY IXMITR

BLOWER MECFUN

CKTBRK MOTOR

ELECON PIPE

ENGINE PUMP

FILTER RELAY

GENERA TRANSF

HEATER TURBIN

HTEXCH VALVE

IBISSW VALVOP

ICNTRL

E-4
Table E-2. Class 1 E electrical power distribution system totals and fractions

Failure Category Totals

Design Failures 259

Aging Failures 716

Test and Maintenance Failures 143

Human-Related Failures 46

Other Failures = 1027

Total 2191

Failure Category Fractions

Design Fraction = 0.118

Aging Fraction = 0.327

Test and Maintenance Fraction = 0.065

Human-Related Fraction 0.021

Other Fraction = 0.469

System Effect Totals

Loss of System Function 51

Degraded System Operation 380

Loss of Redundancy 627

Loss of Subsystem/Channel 582

System Function Unaffected 551

Total 2191

System Effect Fractions

Loss of System Function Fraction 0.023

Degraded System Operation Fraction 0.173

Loss of Redundancy Fraction = 0.286

Loss of Subsystem/Channel Fraction = 0.266

System Function Unaffected Fraction 0.251

E-5
Table E-3. Class 1 E electrical power distribution system component failure category

fractionsa

Component Total Design Aging Testing Human Other

Pipe 3 - 0.667 - - 0.333

Pump 60 0.067 0.633 0.100 - 0.200

Valve Operator 8 0.125 0.625 - - 0.250

Blower: Compressor 215 0.005 0.623 0.056 0.005 0.312

Motor 30 0.100 0.600 0.067 - 0.233

Valve 150 0.173 0.587 0.060 0.007 0.173

Electronic Power 2 - 0.500 - - 0.500

Supply

Airdry 4 - 0.500 _ - 0.500

Heat Exchanger 14 - 0.429 - - 0.571

Instrumentation: 5 - 0.400 0.200 - 0.400

Indicators

Heater 11 0.182 0.364 0.091 - 0.364

Battery 242 0.107 0.326 0.045 0.025 0.496

Engine 496 0.131 0.256 0.099 0.028 0.486

Mechanical Function 55 0.109 0.255 0.091 0.055 0.491

Unit

Relay 88 0.125 0.250 0.045 0.034 0.545

Generator/Alternator/ 390 0.115 0.236 0.033 0.015 0.600

Inverter/Dynometer

Instrumentation: 87 0.069 0.230 0.069 0.011 0.621

Switch

Filter 9 0.444 0.222 0.222 - 0.111

Circuit Breaker 241 0.145 0.212 0.058 0.046 0.539

Turbine 5 0.200 0.200 - - 0.600

Instrumentation: 15 0.067 0.133 0.200 - 0.600

Transmitter

Transformer 30 0.233 0.133 0.033 - 0.600

Electrical Conductors 24 0.542 0.083 0.125 - 0.250

E-6
Table E-3. (continued)

Component Tc

Instrumerftation:

Computation Module

Accumulator

Annunciator

Instrumentation:

Controller

a. Components ordered by aging fraction.

ftal Design Aging Testing Human Other

I 1.000

2

3 0.667

1.000

1.000

0.333

E-7
Table E-4. Auxiliary feedwater system

NSSS: A-BABCOCK & WILCOX

E-WESTINGHOUSE

SYSTEM: A-BABCOCK & WILCOX

HHB-EMERGENCY FEEDWATER

E-WESTINGHOUSE

HHC-AUXILIARY FEEDWATER

COMPONENTS: ANNUNC

CKTBRK

ENGINE

IBISSW

ICNTRL

INDREC

INTCPM

IPWSUP

ISODEV

IXMITR

MECFUN

MOTOR

PIPE

PUMP

RELAY

SUPORT

TURBIN

VALVE

VALVOP

E-8
Table E-5. Auxiliary feedwater system totals and fractions

Failure Category Totals

Design Failures 85

Aging Failures 258

Test and Maintenance Failures 73

Human-Related Failures 15

Other Failures 398

Total 829

Failure Category Fractions

Design Fraction = 0.103

Aging Fraction = 0.311

Test and Maintenance Fraction = 0.088

Human-Related Fraction = 0.018

Other Fraction = 0.480

System Effect Totals

Loss of System Function 5

Degraded System Operation 161

Loss of Redundancy 153

Loss of Subsystem/Channel 255

System Function Unaffected 255

Total 829

System Effect Fractions

Loss of System Function Fraction = 0.006

Degraded System Operation Fraction = 0.194

Loss of Redundancy Fraction = 0.185

Loss of Subsystem/Channel Fraction = 0.308

System Function Unaffected Fraction = 0.308

E-9
Table E-6. Auxiliary feedwater system component failure category fractionsa

Component Tc

Annunciator

Valve 2

Instrumentation:

Isolation Device

Instrumentation:

Computation Module

Instrumentation:

Controller

Instrumentation:

Electrical Power Supply

Relay

Valve Operator

Instrumentation:

Switch

Pump I

Pipe

Mechanical Function

Unit

Motor

Circuit Breaker

Turbine

Instrumentation:

Recorder

Instrumentation:

Transmitter

Support

Engine

a. Components ordered by aging fraction.

)tal

67

2

Design

0.097

Aging

1.000

0.521

0.500

Testing

0.082

Human

0.007

Other

0.292

0.500

26 -

47 0.043

3 0.333

0.385 0.115 0.500

0.340 0.021 0.596

0.333 0.333

12

03

24

10

5

16

7

22

60

19

0.250

0.078

0.042

0.091

0.400

0.062

0.136

0.150

0.333

0.252

0.250

0.245

0.200

0.188

0.143

0.136

0.133

0.105

0.104

0.045

0.167

0.107

0.091

0.250

0.227

0.100

-0.105

0.026

0.019

0.027

0.125

0.050

0.039

0.250

0.544

0.708

0.545

0.400

0.375

0.857

0.500

0.567

0.789

0.688

0.455

0.667

77 0.143

22

6

0.364 0.136

0.333

E-10
Table E-7. Component cooling water system

NSSS: A-BABCOCK & WILCOX

C-GENERAL ELECTRIC

SYSTEM: A-BABCOCK & WILCOX

WBB-COMPONENT COOLING WATER

C-GENERAL ELECTRIC

WBA-REACTOR BLDG. CLOSED COOLING WATER

COMPONENTS: ACCUMU

CKTBRK

HTEXCH

IBISSW

ICNTRL

INDREC

INTCPM

IXMITR

MOTOR

PIPE

PUMP

RELAY

SUPORT

VALVE

VALVOP

E-I1
Table E-8. Component cooling water system totals and fractions

Failure Category Totals

Design Failures 27

Aging Failures 110

Test and Maintenance Failures 33

Human-Related Failures 8

Other Failures 108

Total 286

Failure Category Fractions

Design Fraction = 0.094

Aging Fraction = 0.385

Test and Maintenance Fraction = 0.115

Human-Related Fraction = 0.028

Other Fraction = 0.378

System Effect Totals

Loss of System Function 0

Degraded System Operation 62

Loss of Redundancy 45

Loss of Subsystem/Channel 90

System Function Unaffected 89

Total 286

System Effect Fractions

Loss of System Function Fraction = 0.000

Degraded System Operation Fraction = 0.217

Loss of Redundancy Fraction = 0.157

Loss of Subsystem/Channel Fraction = 0.315

System Function Unaffected Fraction = 0.311

E- 12
Table E-9. Component cooling water system component failure category fractionsa

Component Total Design Aging Testing Human Other

Pipe I - 1.000 - -

Instrumentation: 4 - 0.750 0.250 - -

Controller

Pump 54 0.074 0.685 0.056 - 0.185

Motor 13 - 0.538 0.154 - 0.308

Heat Exchanger 30 0.133 0.433 0.033 0.033 0.367

Valve 63 0.048 0.381 0.159 0.032 0.381

Circuit Breaker 21 0.095 0.333 0.048 0.048 0.476

Instrumentation: 14 - 0.214 0.286 - 0.500

Recorder

Valve Operator 52 0.173 0.212 0.154 0.038 0.423

Support 5 0.200 0.200 - - 0.600

Instrumentation: 11 0.091 0.182 0.091 - 0.636

Switch

Instrumentation: 13 0.154 0.077 0.154 0.077 0.538

Transmitter

Relay 3 0.333 - - 0.333 0.333

Accumulator I - - - - 1.000

Instrumentation: 1 - - - - 1.000

Computation Module

a. Components ordered by aging fraction.

E-13
Table E-10. High-pressure injection system

NSSS: A-BABCOCK & WILCOX

E-WESTINGHOUSE

SYSTEM: A-BABCOCK & WILCOX

PCB-LETDOWN PURIFICATION AND MAKEUP

SFD-HIGH PRESSURE INJECTION

E-WESTINGHOUSE

SFK-HIGH PRESSURE SAFETY INJECTION

SFKUHI-HIGH PRESSURE SAFETY INJECTION -

UPPER HEAD INJECTION SUBSYSTEM

COMPONENTS: ACCUMU

CKTBRK

FILTER

HEATER

HTEXCH

IBISSW

ICNTRL

INDREC

INTCPM

IXMITR

MOTOR

PIPE

PUMP

RELAY

SUPORT

VALVE

VALVOP

E-14
Table E-11. High-pressure injection system totals and fractions

Failure Category Totals

Design Failures 122

Aging Failures 221

Test and Maintenance Failures 83

Human-Related Failures 27

Other Failures 583

Total 1036

Failure Category Fractions

Design Fraction = 0.118

Aging Fraction - 0.213

Test and Maintenance Fraction 0.080

Human-Related Fraction 0.026

Other Fraction = 0.563

System Effect Totals

Loss of System Function 7

Degraded System Operation 197

Loss of Redundancy 138

Loss of Subsystem/Channel 251

System Function Unaffected 443

Total 1036

System Effect Fractions

Loss of System Function Fraction = 0.007

Degraded System Operation Fraction = 0.190

Loss of Redundancy Fraction = 0.133

Loss of Subsystem/Channel Fraction = 0.242

System Function Unaffected Fraction = 0.428

E-15
Table E-12. High-pressure injection system component failure category fractionsa

Component Tot

Relay

Support 3

Filter

Heat Exchanger

Valve 30

Pump 8

Instrumentation: I

Recorder

Valve Operator 16

Circuit Breaker 4

Instrumentation: 14

Transmitter

Heater 3

Instrumentation: I

Controller

Instrumentation: 15

Switch

Accumulator

Motor

Pipe

Instrumentation:

Computation Module

a. Components ordered by aging fraction.

al

1

2

6

9

7

6

8

1

3

1

Design

0.156

0.444

0.127

0.105

0.081

0.163

0.106

0.111

0.158

Aging

1.000

0.375

0.333

0.333

0.326

0.314

0.278

0.211

0.209

0.113

0.111

0.105

0.039

Testing

0.031

0.500

0.085

0.116

0.143

0.070

0.071

0.111

Human

0.031

0.020

0.047

0.031

0.047

0.007

0.167

Other

0.406

0.167

0.222

0.443

0.419

0.722

0.534

0.512

0.702

0.500

0.737

0.830

0.750

0.667

0.400

0.833

6

9

3 0.124 0.007

4

9

5

6

0.111

0.400

0.167

0.111

0.200

0.250

0.111

E-16
Table E-13. Main feedwater system

NSSS: A-BABCOCK & WILCOX

C-GENERAL ELECTRIC

SYSTEM: A-BABCOCK & WILCOX

HHA-FEEDWATER

C-GENERAL ELECTRIC

CHA-FEEDWATER

COMPONENTS: CKTBRK

FILTER

HTEXCH

IBISSW

ICNTRL

INDREC

INTCPM

IPWSUP

ISODEV

IXMITR

MECFUN

MOTOR

PIPE

PUMP

RELAY

SUPORT

TURBIN

VALVE

VALVOP

E-17
Table E-14. Main feedwater system totals and fractions

Failure Category Totals

Design Failures 94

Aging Failures 310

Test and Maintenance Failures 49

Human-Related Failures 6

Other Failures 368

Total 827

Failure Category Fractions

Design Fraction 0.114

Aging Fraction 0.375

Test and Maintenance Fraction 0.059

Human-Related Fraction 0.007

Other Fraction 0.445

System Effect Totals

Loss of System Function 9

Degraded System Operation 153

Loss of Redundancy 102

Loss of Subsystem/Channel 157

System Function Unaffected 406

Total 827

System Effect Fractions

Loss of System Function Fraction 0.011

Degraded System Operation Fraction 0.185

Loss of Redundancy Fraction 0.123

Loss of Subsystem/Channel Fraction 0.190

System Function Unaffected Fraction 0.491

E-18
Table E-15. Main feedwater system component failure category fractionsa

Component

Relay

Heat Exchanger

Valve

Instrumentation:

Electronic Power

Supply

Instrumentation:

Switch

Pump

Circuit Breaker

Valve Operator

Mechanical Function

Unit

Total

3

21

334

2

Design

0.048

0.108

Aging

1.000

0.667

0.524

0.500

Testing

0.048

0.042

Human

0.006

Other

0.238

0.320

0.500

11 0.182 0.455 0.364

49

9

113

15

Pipe 4

Instrumentation: 41

Computation Module

Turbine 26

Motor 5

Instrumentation: 10

Controller

Instrumentation: 82

Transmitter

Support 55

Instrumentation: 43

Recorder

Instrumentation: I

Isolation Device

Filter 3

a. Components ordered by aging fraction.

0.143

0.111

0.071

0.067

0.500

0.115

0.600

0.024

0.491

0.023

0.449

0.444

0.319

0.267

0.250

0.244

0.231

0.200

0.200

0.171

0.127

0.116

0.102

0.106

0.067

0.024

0.020

0.018

0.286

0.444

0.487

0.600

0.250

0.732

0.577

0.200

0.700

0.077

0.100

0.049 0.756

0.055

0.047

0.018 0.309

0.814

1.000

1.000

E-19
Table E-16. Reactor protection trip system

NSSS: C-GENERAL ELECTRIC

E-WESTINGHOUSE

SYSTEM: C-GENERAL ELECTRIC

IBA-REACTOR PROTECTION

IBAIAA-REACTOR PROTECTION - NEUTRON

MONITORING SUBSYSTEM

E-WESTINGHOUSE

IBG-REACTOR PROTECTION AND LOGIC

IBK-ENGINEERED SAFEGUARDS ACTUATION AND

LOGIC

COMPONENTS: ANNUNC

CKTBRK

ELECON

GENERA

IBISSW

ICNTRL

INDREC

INTCPM

IPWSUP

ISODEV

IXMITR

RELAY

E-20
Table E-17. Reactor protection trip system totals and fractions

Failure Category Totals

Design Failures 448

Aging Failures 740

Test and Maintenance Failures 189

Human-Related Failures 26

Other Failures = 1761

Total 3170

Failure Category Fractions

Design Fraction - 0.141

Aging Fraction - 0.233

Test and Maintenance Fraction = 0.060

Human-Related Fraction = 0.008

Other Fraction = 0.556

System Effect Totals

Loss of System Function 6

Degraded System Operation 529

Loss of Redundancy 538

Loss of Subsystem/Channel = 1247

System Function Unaffected 851

Total 3170

System Effect Fractions

Loss of System Function Fraction = 0.002

Degraded System Operation Fraction = 0.167

Loss of Redundancy Fraction = 0.170

Loss of Subsystem/Channel Fraction = 0.393

System Function Unaffected Fraction = 0.268

E-21
Table E-18. Reactor protection trip system component failure category fractionsa

Component Total Design Aging Testing Human Other

Instrumentation: 30 0.033 0.367 - - 0.600

Isolation Device

Annunciator 3 0.333 0.333 - - 0.333

Generator/Alternator/ 16 0.250 0.312 0.125 - 0.312

Inverter

Instrumentation: 851 0.063 0.276 0.033 0.009 0.618

Computation Module

Instrumentation: 199 0.126 0.271 0.060 0.005 0.538

Recorder

Circuit Breaker 41 0.098 0.268 0.098 - 0.537

Instrumentation: 254 0.075 0.252 0.043 - 0.630

Electronic Power

Supply

Instrumentation: 199 0.090 0.241 0.055 - 0.613

Controllers

Relay 335 0.284 0.230 0.033 0.018 0.436

Electrical Conductors 10 0.100 0.200 - - 0.700

Instrumentation: 753 0.117 0.189 0.106 0.009 0.571

Transmitter

Instrumentation: 479 0.288 0.188 0.063 0.008 0.453

Switch

a. Components ordered by aging fraction.

E-22
Table E-19. Residual heat removal system

NSSS: C-GENERAL ELECTRIC

SYSTEM: CFA-RESIDUAL HEAT REMOVAL/LOW PRESSURE

INJECTION

COMPONENTS: CKTBRK

ELECON

HTEXCH

IBISSW

ICNTRL

INDREC

INTCPM

IPWSUP

IXMITR

MOTOR

PIPE

PUMP

RELAY

SUPORT

VALVE

VALVOP

E-23
Table E-20. Residual heat removal system totals and fractions

Failure Category Totals

Design Failures 126

Aging Failures 245

Test and Maintenance Failures 75

Human-Related Failures 22

Other Failures 590

Total 1058

Failure Category Fractions

Design Fraction = 0.119

Aging Fraction = 0.232

Test and Maintenance Fraction = 0.071

Human-Related Fraction = 0.021

Other Fraction . 0.558

System Effect Totals

Loss of System Function 10

Degraded System Operation 173

Loss of Redundancy 168

Loss of Subsystem/Channel 212

System Function Unaffected 495

Total 1058

System Effect Fractions

Loss of System Function Fraction = 0.009

Degraded System Operation Fraction - 0.164

Loss of Redundancy Fraction = 0.159

Loss of Subsystem/Channel Fraction = 0.200

System Function Unaffected Fraction = 0.468

E-24
Table E-21. Residual heat removal system component failure category fractionsa

Component Total Design Aging Testing Human Other

Heat Exchanger 33 0.121 0.485 0.030 - 0.364

Valve 250 0.076 0.464 0.056 0.016 0.388

Pump 28 0.214 0.321 - 0.107 0.357

Valve Operator 227 0.137 0.225 0.079 0.035 0.524

Circuit Breaker 71 0.183 0.197 0.085 - 0.535

Instrumentation: 6 - 0.167 - - 0.833

Computation Module

Relay 26 0.077 0.154 0.115 - 0.654

Support 101 0.119 0.119 0.050 0.030 0.683

Instrumentation: 43 0.093 0.093 0.116 - 0.698

Recorder

Instrumentation: 11 0.182 0.091 0.182 - 0.545

Controller

Instrumentation: 175 0.109 0.086 0.051 0.017 0.737

Switch

Instrumentation: 68 0.059 0.029 0.162 0.015 0.735

Transmitter

Pipe 10 0.800 - - - 0.200

Motor 6 0.333 - 0.167 - 0.500

Electrical Conductor I - - - - 1.000

Instrumentation: 2 - - - - 1.000

Electrical Power

Supply

a. Components ordered by aging fraction.

E-25
Table E-22. Service water system

NSSS: A-BABCOCK & WILCOX

C-GENERAL ELECTRIC

E-WESTINGHOUSE

SYSTEM: A-BABCOCK & WILCOX

WAB-LOW PRESSURE SERVICE WATER

C-GENERAL ELECTRIC

WAA-ESSENTIAL SERVICE WATER

E-WESTINGHOUSE

WAD-NUCLEAR SERVICE WATER

COMPONENTS: CKTBRK

ELECON

FILTER

IBISSW

ICNTRL

INDREC

INTCPM

IPWSUP

IXMITR

MOTOR

PIPE

PUMP

RELAY

SUPORT

VALVE

VALVOP

E-26
Table E-23. Service water system totals and fractions

Failure Category Totals

Design Failures 88

Aging Failures = 570

Test and Maintenance Failures 83

Human-Related Failures 16

Other Failures = 515

Total 1272

Failure Category Fractions

Design Fraction = 0.069

Aging Fraction - 0.448

Test and Maintenance Fraction - 0.065

Human-Related Fraction = 0.013

Other Fraction = 0.405

System Effect Totals

Loss of System Function 3

Degraded System Operation = 216

Loss of Redundancy = 233

Loss of Subsystem/Channel = 435

System Function Unaffected = 385

Total 1272

System Effect Fractions

Loss of System Function Fraction = 0.002

Degraded System Operation Fraction = 0.170

Loss of Redundancy Fraction = 0.183

Loss of Subsystem/Channel Fraction = 0.342

System Function Unaffected Fraction = 0.303

E-27
Table E-24. Service water system component failure category fractionsa

Component

Instrumentation:

Electronic Power

Supply

Filter

Pump

Pipe

Valve

Instrumentation:

Controller

Total

2

98

248

18

362

17

Design

0.102

0.044

0.066

0.059

Aging

1.000

0.571

0.569

0.556

0.555

0.529

Testing

0.041

0.077

0.056

0.039

0.118

Human

0.025

Other

0.286

0.310

0.389

0.315

0.294

Motor

Circuit Breaker

Valve Operator

Instrumentation:

Switch

Instrumentation:

Recorder

Instrumentation:

Transmitter

Support

64

48

307

38

0.078

0.062

0.072

0.079

0.391

0.354

0.293

0.263

0.016

0.083

0.117

0.026

0.016

0.042

0.013

0.500

0.458

0.505

0.632

22 0.045

27 0.037

0.227 0.727

0.111 0.037 0.815

I

Relay

Electrical Conductor

Instrumentation:

Computation Module

a. Components ordered by aging fraction.

0

5

4

2

0.300

0.600

0.250

0.100 0.600

0.400

0.750

1.000

E-28
Table E-25. Standby liquid control system

NSSS: C-GENERAL ELECTRIC

SYSTEM: PCA-STANDBY LIQUID CONTROL

COMPONENTS: ACCUMU

CKTBRK

HEATER

IBISSW

ICNTRL

INDREC

IPWSUP

IXMITR

PUMP

RELAY

SUPORT

VALVE

VALVOP

E-29
Table E-26. Standby liquid control system totals and fractions

Failure Category Totals

Design Failures 10

Aging Failures 49

Test and Maintenance Failures 10

Human-Related Failures I

Other Failures 103

Total 173

Failure Category Fractions

Design Fraction 0.058

Aging Fraction 0.283

Test and Maintenance Fraction 0.058

Human-Related Fraction 0.006

Other Fraction 0.595

System Effect Totals

Loss of System Function 0

Degraded System Operation 39

Loss of Redundancy 24

Loss of Subsystem/Channel 34

System Function Unaffected 76

Total 173

System Effect Fractions

Loss of System Function Fraction 0.000

Degraded System Operation Fraction 0.225

Loss of Redundancy Fraction 0.139

Loss of Subsystem/Channel Fraction 0.197

System Function Unaffected Fraction 0.439

E-30
Table E-27. Standby liquid control system component failure category fractionsa

Component Total Design Aging Testing Human Other

Pump 19 0.053 0.632 - - 0.316

Relay 2 - 0.500 - - 0.500

Accumulator 12 0.083 0.333 0.167 - 0.417

Instrumentation: 17 0.118 0.294 - - 0.588

Transmitter

Instrumentation: 14 - 0.286 - - 0.714

Recorder

Instrumentation: 4 - 0.250 - - 0.750

Electronic Power

Supply

Valve 66 0.076 0.242 0.091 - 0.591

Instrumentation: 5 - 0.200 0.200 - 0.600

Controller

Heater 10 - 0.200 0.100 - 0.700

Support 6 - 0.167 - - 0.833

Instrumentation: 14 - 0.143 - - 0.857

Switch

Circuit Breaker 2 - - - 0.500 0.500

Valve Operator 2 0.500 - - - 0.500

a. Components ordered by aging fraction.

E-31
APPENDIX F

REPORTED FAILURE CAUSE DATA SUMMARIES

F-i
APPENDIX F

REPORTED FAILURE CAUSE DATA SUMMARIES

Specific vendors and plant identifications are

maintained in the data base created during this

study. To preserve the proprietary nature of the data

and yet obtain acceptable data populations, the failure cause data presented in this report are systemspecific. Tables F-i and F-2 summarize the failure

cause data. Table F-i lists components having five

or more failure counts, and Table F-2 lists those

with less than five failure counts. Tables F-3

through F-19 show the number of failure causes, the

failure cause fractions, the upper bound failure

cause fraction, and the lower bound failure cause

fraction for each failure mode of each component,

excluding the unclassified causes. These latter tables

do not contain any components having less than five

failure counts. The failure causes are presented in

alphabetical order in the tables. Table F-20 lists the

system, component, failure mode, system effect,

and aging classification for all the records coded

"unclassifiable."

F-3
TABLE F-1. SUMMARY OF DATA ANALYZED DURING THE FAILURE CAUSE IDENTIFICATION ANALYSISa

System

Essential Service Water System

b

Components

Circuit Breaker, AC

Failure

Mode

Failure Mode Code

c

Counts

11

I6

Fails to Operate

Opens (Premature)

GFP

GSO

Flow Switch

Check Valve

IT1

Flow Indicator

Hand Control Valve

Motor-Driven Pump

Motor-Operated Valve

Pressure Indicator

Pnuematic-Operated Valve

Strainer

Erroneous/Erratic Signals

External Leakage

Fails to Open

Internal Leakage

Erroneous/Erratic Signals

Fails to Operate

External Leakage

Fails to Close

Fails to Open

Failure to Operate as Required

Fails to Open/Fails to Close

External Leakage

Fails to Start

Fails to Run

External Leakage

Fails to Close

Fails to Open

Failure to Operate as Required

Fails to Open/Fails to Close

Erroneous/Erratic Signals

Fails to Operate

External Leakage

Fails to Close

Fails to Open

Failure to Operate as Required

Fails to Open/Fails to Close

Loss of Function

Plugged

Fails to Operate

GEE

GEL

GFO

GIL

GEE

G(P 4

GEL

GFO

uFR

GUC

2

y

1

6

1

16

2

4

25

GEL

(ifS

GFU

GEL

GFC

GFO

GFR

GOC

64

91

7

43

27

17

17

GEE

GFP

5

1

GEL

GFC

GFO

GFR

GOC

GLF

GPL

GFP

5

15

9

13

S

13

Instrumentation & Uninterruptible 5

Power Supply System--Class 1E

Circuit Breaker, AC

Inverter Loss of Function GLF 63
TABLE F-1. (continued)

System

DC Power System - lE

Emergency On-site Power Supply System

Componentsb

Battery

Battery Charger

Circuit Breaker, AC

Diesel Generator

Failure Mode

Loss of Function

Loss of Function

Fails to Operate

Fails to Start

Fails to Run

No Failure

Failure

Mode c

Code Counts

GLF 10

GLF 3b

UtP 5

GFS lb

uFU 46

GNF 4v

a. See Table F-20 for summary of data categorized as unclassifiable.

b. See Table F-2 for those components having less than S counts.

c. Total counts: 669.

71
TABLE F-2. SUMMARY OF COMPONENTS HAVING LESS THAN 5 COUNTS EACHa

System

Essential Service Water System

Components

Position-Limit Switch

Pressure Switch

IT1

Level Switch

DC Overcurrent Relay

Flow Modifier

Electric Power Supply

Level Transmitter

Motor

Differential Pressure

Indicating Switch

Differential Pressure

Control Recorder

Pipe

Relay

Relief Valve

Snubber

Support

Safety Relief Valve

Temperature Indicator

Temperature Control

Indicator

Temperature Switch

Failure Mode

Erroneous/Erratic Signals

Erroneous/Erratic Signals

Fails to Operate

Erroneous/Erratic Signals

Fails to Operate

Erroneous/Erratic Signals

Loss of Function

Fails to Operate

Fails to Run

Erroneous/Erratic Signals

Erroneous/Erratic Signals

Fails to Operate

Plugged

Rupture

Fails to Close

Fails to Open

Short Circuit

Fails to Close

Loss of Function

Loss of Function

Fails to Close

Erroneous/Erratic Signals

Fails to Operate

Fails to Operate

Failure

Mode

Code

GEE

GEE

GFP

GEE

GFP

GEE

GLF

GFP

GFU

GtE

GEE

GFP

GPL

GRU

GFC

GFU

GSH

GFC

GLF

GLF

GFC

GEE

GFP

uFP

Counts

3

1

1

1

3

1

3

4

2

1

Erroneous Output GtU I
TABLE F-2. (continued)

System

Essential Service Water System (continued)

Medium Voltage Power Supply System--Class lE

Low Voltage Power Supply System--Class 1E

Components

Thermowell

Vent Valve

Zone Modifier

Circuit Breaker, AC

Cable

Transformer

Circuit Breaker, AC

Bus

Relay

Circuit Breaker, AC

Temperature Indicator

Timer

Failure Mode

Loss of Function

Fails to Close

Fails to Open/Fails to Close

Erroneous/Erratic Signals

Fails to Operate

Opens (Premature)

Loss of Function

Loss of Function

Fails to Operate

Loss of Function

Fails to Operate

Short Circuit

Fails to Operate

Erroneous/Erratic Signals

Erroneous/Erratic Signals

Failure

Mode

Code

GLF

GFC

GOL

GEE

GFP

GSO

GLF

GLF

GFP

GLF

GFP

GSH

GFP

GEE

GEE

Countsb

I

4

1

3

. 4

3

2

DC Power System--Class lE

Emergency On-Site Power Supply System

a. Table summary does not contain data for any failure categorized unclassifiable

b. Total counts: 63.

(Table F-20).
TABLE F-3. FAILURE CAUSE TALLIES, FAILURE CAUSE FRACTIONS, AND AGING FRACTIONS FOR SWS CHECK VALVES

SYSTEM

ESSENTIAL SERVTICE ATER SYSTEM

COMPONENT

CHrCK VALVES

Failure Mode: EXTERNAL LEAKAGE - GEL

Failure Cause

Failure Cause Code EBR

Failure Cause Count I

Failure Cause Fraction 0.500

Totals

HPM

I2 2

00

IAging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

1/0/0

0.500

0.500

0.500

0/1/0

0.000

0.000

1/l/U

1.000

0.50U

0.500

Failure Mode: FAILS TO OPEN - GFO

Failure Cause

Failure Cause Code DCI

Failure Cause Count I

Failure Cause Fraction 0.250

/

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

EBE

0.250

1/0/0

0.250

0.250

EBR

0.250

1/0/0

0.250

0.250

ECC

1

0.250

1 /U/O

0.250

0.250

4

1.U00

3/1/0

Totals

0/1/0

0.000

0.000

0.75U

0.750
TABLE F-3. (continued)

SYSTEM

ESSENTIAL SERVICE WATER SYSTEM

COMPONENT

CHECK VALVES

Failure Mode: INTERNAL LEAKAGE - GIL

Failure Cause

Failure Cause Code DE

Failure Cause Count I

Failure Cause Fraction 0.040

Totals

Aqnu

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

EBE

3

0.120

3/1/0

0.120

0.120

* EBR ECC EDB EDI _

12 6 1 2

0.480 0.240 0.040 0.080

1/0/0

0.040

0.040

12/0/0

0.480

0.480

6/0/0 0/0/1 1/1/0

0.040

0.040

25

1.U000

23/1/I

0.*960

U.92U

0.240

0.240

0.040

0.000
TABLE F-4. FAILURE CAUSE TALLIES, FAILURE CAUSE FRACTIONS, AND AGING FRACT1O0S FOR SWS HANU CONTRUL VALVES

SYSTEM

ESSENTIAL SERVI WATER SYSTEM

COMPONENT

hAND CONTROL VALVES

Failure Mode: EXTERNAL LEAKAGE - GEL

Failure Cause

Failure Cause Code EBR

Failure Cause Count I

Failure Cause Fraction 0.500

Totals

ECC

1

0.500

2

1 .O(U

IT0

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

1/0/0

0.500

0.500

1/0/0 2/U/U

0.500

0.500

I .UUU

1.UU0

Failure Mode: FAILS TO CLOSE - GFC

Failure Cause

Failure Cause Code EBE

Failure Cause Count I

Failure Cause Fraction 0.143

Aging

Yes/No/Unknown 1/0/0

Aging Fractions

Upper Bound 0.143

Lower Bound 0.143

Totals

EBR

2

0.286

2/0/0

0.286

0.286

ECC

3

0.429

3/0/0

0.429

0.429

EDI

0.143

1/0/0

0.143

0.143

7

I .000

7//0U

1 . UUO

1.000
TABLE F-4. (continued)

SYSTEM

ESSENTIAL SERVICWATER SYSTEM

COMPONENT

HAND tURTR=VALVES

Failure Mode: FAILS TO OPEN - GFO

Failure Cause

Failure Cause Code HEO

Failure Cause Count I

Failure Cause Fraction 1.000

Totals

1 .uUU

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

0/l/0 Oil/i

0.000

0.000

0.000

0.000

Failure Mode: FAILURE TO OPERATE AS REQUIRED - GFR

Failure Cause

Failure Cause Code ECC E08

Failure Cause Count 1 I

Failure Cause Fraction 0.167 0.167

Totals

HEM

1

0.167

HED

3

0.500

6

1.000

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

1/0/0

0.167

0.167

0/0/1

0.167

0.000

0/1/0

0.000

0.000

0/3/0 1/4/1

0.000

0.000

0.334

0.167
TABLE F-4. (continued)

SYSTEM

ESSENTIAL SERMllE-WATER SYSTEM

COMPONENT

HAND CONTROL VALVES

Failure Mode: FAILS TO OPEN/FAILS TO CLOSE - GOC

Failure Cause

Failure Cause Code EDB

Failure Cause Count I

Failure Cause Fraction 1.000

Agin

Yes/No/Unknown 1/0/0

Aging Fractions

Upper Bound 1.000

Lower Bound 1.000

Totals

l.UUO

1.uuO

71J
TABLE F-S. FAILURE CAUSE TALLIES, FAILURE CAUSE FRACTIONS, AND AGING FRACTIONS FOR SWS MOTOR-OPEHATEU VALVES

SYSTEM

ESSENTIAL SERV1CEWATER SYSTEM

COMPONENT

MOTOR-OPERATEU VALVES

Failure Mode: FAILS TO CLOSE - GFC

Failure Cause

Failure Cause Code DCI

Failure Cause Count I

Failure Cause Fraction 0.023

Totals

EBE

3

0.070

EBR

6

0.140

ECC

2

0.047

EOB

23

0.535

EDI

3

0.070

ELO ELK ELS

1 1 1

0.023 0.023 0.023

71

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

0/1/0

0.000

0.000

3/0/0

0.070

0.070

6/0/0

0.140

0.140

2/0/0 0/2/21 3/0/0

0.070

0.070

0/U/i

0.023

0.000

1 /U/0

0.023

0.023

0/0/1

0.023

0.000

0.047

0.047

0.488

0.000

Failure Mode: FAILS TO CLOSE - GFC(continued)

Failure Cause

Failure Cause Code HEM HEO

Failure Cause Count 1 I

Failure Cause Fraction 0.023 0.023

Totals

43

1.u~u

Agng

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

0/1/0

0.000

0.000

0/1/0 15/b/Z3

0.000

0.000

U.884

0.350
TABLE F-5. (continued)

SYSTEM

ESSENTIAL SEMiCE WATER SYSTEM

COMPONENT

MOTOR-OPERATED ALYES

Failure Mode: FAILS TO OPEN - GFO

Failure Cause

Failure Cause Code DM

Failure Cause Count 1

Failure Cause Fraction 0.037

Aging

Totals

EBF

0.037

EBR

3

0.111

EDB

8

0.296

EDI

2

0.074

EDU EL

2 2

0.074 0.074

ELK

3

U.U37

ELO

0.111

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

0/0/1

0.037

0.000

1/0/0

0.037

0.037

3/0/0

0.111

0.111

1/2/5 1/0/1 0/1/1

0.037

0.000

O/U/2

0.074

0.000

O/U/1

O.U37

0.000

u/0/3

0.111

0.000

0.222

0,037

O.U74

0.037

Failure Mode: FAILS TO OPEN - GFO(continued)

Failure Cause

Failure Cause Code ELS ELT

Failure Cause Count 1 I

Failure Cause Fraction 0.037 0.037

Totals

HEM

0

0.037

HEO_ _ _

0.037

27

1.000

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

0/0/1

0.037

0.000

1/0/0 0/1/0 0/1/0 7/5/15

0.037

0.037

0.000

0.000

0.000

0.000

0.814

0.259
TABLE F-S. (continued)

SYSTEM

ESSENTIAL SERVICWATER SYSTEM

COMPONENT

MOTOR-OPERATED VALVES

Failure Mode: FAILURE TO OPERATE AS REQUIRED - GFR

Failure Cause

Failure Cause Code DEI EBE

Failure Cause Count 1 2

Failure Cause Fraction 0.059 0.118

Totals

r11

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

0/1/0

0.000

0.000

EBR

3

0.176

3/0/0

0.176

0.176

ECC

1

0.059

2/0/0

0.118

0.118

1/0/0 1/1/3 0/0/1

0.059

0.000

O/U/i

0.059

0.000

2/0/U

0.118

0.118

0/1/U

0.000

0.000

EDB EL ELO EVM HPM

5 1 1 2 1

0.294 0.059 0.059 0.118 0.059

17

1.OOu

9/3/S

0.824

0.53U

0.059

0.059

0.235

0.059

Failure Mode: EXTERNAL LEAKAGE - GEL

Failure Cause

Failure Cause Code EBR

Failure Cause Count 5

Failure Cause Fraction 0.714

Totals

ECC

2

0.286

7

1 .UUU

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

5/0/0

0.714

0.714

2/0/0 7/U/U

0.286

0.286

1 . uuu

I .uOU
TABLE F-5. (continued)

SYSTEM

ESSENTIAL SE1ZV1~FWATER SYSTEM

COMPONENT

MOTOR-UPERATEU VALVES

Failure Mode: FAILS TO OPEN/FAILS TO CLOSE - GOC

Failure Cause

Failure Cause Code DC DM

Failure Cause Count 1 1

Failure Cause Fraction 0.059 0.059

Totals

EBR EDB ELE ELH ELK EMW EVN

2 2 4 1 2 3 1

0.118 0.118 0.235 0.059 0.118 0.176 0.059

17

1.000

0'.1

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

0/1/0 2/0/0

0.118

0.118

1/0/1 1/2/1 O/u/l

0.059

O.OOU

0/0/2 1 /U/U 5/1/7

U. 7Ud

0.2ia

0.000

0.000

0.059

0.000

0.118

0.059

0.118

0.059

0.118

0.000

O.U59

0.000

O.Ub9

U.059
TABLE F-6. FAILURE CAUSE TALLIES, FAILURE CAUSE FRACTIONS, AND AGING FkACTIONS FOR SWS PNLUMAIIC-UPEKATLU VALVLS

SYSTEM

ESSENTIAL SERVICE WATER SYSTEM

COMPONENT

PNEUMATIC-OPE`ATED VALVES

Failure Mode: EXTERNAL LEAKAGE - GEL

Failure Cause

Failure Cause Code EBR

Failure Cause Count 5

Failure Cause Fraction 1.000

Totals

5

1.000

71I

-J

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

5/0/0

1.000

1.000

5/0/0

1 .0UU

1.000

Failure Mode: FAILS TO CLOSE - GFC

Failure Cause

Failure Cause Code EBR

Failure Cause Count 5

Failure Cause Fraction 0.333

Total s

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

ECC

1

0.067

1/0/0

0.067

0.067

EDB

4

0.267

0/1/3

0.200

0.000

EDI

4

0.267

EVM _

0.067

15

1.000

5/0/0

0.333

0.333

4/0/0 1/0/0 1/1/3

0.267

0.267

0.067

0.067

U. 934

0.734
TABLE F-6. (continued)

SYSTEM

ESSENTIAL SER=VIWATER SYSTEM

COMPONENT

PNEUMATIC-OPERATED VALVES

Failure Mode: FAILS TO OPEN - GFO

Failure Cause

Failure Cause Code EBF

Failure Cause Count I

Failure Cause Fraction 0.111

Totals

71

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

EBR

3

0.333

3/0/0

0.333

0.333

EDB

2

0.222

0/0/2

0.222

0.000

EDI

2

0.222

EDU _

0.111

1/0/0

0.111

0.111

2/0/0 0/(/1 oiO/4

9

1.UOU

0.222

0.222

0.111

0.000

1.U00

0.666

Failure Mode: FAILURE TO OPERATE AS REQUIRED - GFR

Failure Cause

Failure Cause Code EBB EBR

Failure Cause Count 1 5

Failure Cause Fraction 0.077 0.385

Totals

EDB

2

0.154

EDI

0.077

ELD

1

0.077

EVM

2

0.154

HA

1

0.077

13

1LOW

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

1/0/0

0.077

0.077

5/0/0

0.385

0.385

0/0/2

0.154

0.000

1 /U/U 1/0/0 2/U/0

0.154

0.154

0/1/0 lU/1/W

0.077

0.077

0.077

0.077

0. 0U

0.000

U. 924

U.771
TABLE F-6. (continued)

SYSTEM

ESSENTIAL SERVICE WATER SYSTEM

COMPONENT

PNEUMATIC-OPERATED VALVES

Failure Mode: FAILS TO OPEN/FAILS TO CLOSE - GOC

Failure Cause

Failure Cause Code EBR ECC

Failure Cause Count 1 1

Failure Cause Fraction 0.200 0.200

Aging

Yes/No/Unknown 1/0/0 1/0/0

Aging Fractions

Upper Bound 0.200 0.200

Lower Bound 0.200 0.200

EDB

0.200

0/0/1

0.200

0.000

EVM

2

0.400

2/0/0

0.400

0.400

Totals

5

1.000

4/0/1

1 .OuU

0.800
TABLE F-7. FAILURE CAUSE TALLIES, FAILURE CAUSE FRACTIONS, AND AGING FRACTIONS FOR SWS MOTOR-DRIVEii PU14PS

SYSTEM

ESSENTIAL SERVICE WATER SYSTEM

COMPONENT

MOTOR-URIVEN PUMPS

Failure Mode: EXTERNAL LEAKAGE - GEL

Failure Cause

Failure Cause Code EBB

Failure Cause Count I

Failure Cause Fraction 0.016

Totdls

* EBF

1

0.016

EBR

45

0.703

- EDB

0.016

EDI

9

0.141

EVM

2

0.031

HAM

1

0.016

HEM

1

0.016

HEO

1

0.01 o

01

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

1/0/0

0.016

0.016

1/0/0

0.016

0.016

45/0/0 O/u/I 8/1/U 2/0/U 0/1/U 0/1/U

0.000

0.000

1 /u/U

U.0lb

0.016

0.703

0.703

0.016

0.000

0.125

0.125

0.031

0.031

O.OUU

0.000

Failure Mode: EXTERNAL LEAKAGE - GEL(continued)

Failure Cause

Failure Cause Code SPM SPO

Failure Cause Count 1 1

Failure Cause Fraction 0.016 0.016

Totals

b4

1 .UUU

Aqinq

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

1/0/0

0.016

0.016

1/0/0

0.016

0.016

6U/J/l

U.9as

U.939
TABLE F-7. (continued)

SYSTEM

ESSENTIAL SERVICE WATER SYSTEM

COMPONENT

MOTOR-URIVEN PUMPS

Failure Mode: FAILS TO RUN - GFU

Failure Cause

Failure Cause Code DC

Failure Cause Count 1

Failure Cause Fraction 0.011

Totals

DCI

0.011

DM

3

0.033

EAO

0.011

EBE

2

0.022

EBR

29

0.319

ECC

4

0.044

ELb

10

0.110

EDI

23

0.253

t'J

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

1/0/0

0.011

0.011

1/0/0

0.011

0.011

0/3/0

0.000

0.000

1/0/0 2/0/0 29/0/0 4/U/0 1/4/5

0.066

0.011

16/7/0

0.176

0.176

0.011

0.011

0.022

0.022

0.319

0.319

0.044

0.044

Failure Mode: FAILS TO RUN - GFU(continued)

Failure Cause

Failure Cause Code EDU EI

Failure Cause Count 4 1

Failure Cause Fraction 0.044 0.011

Totals

ELI

2

0.022

ELO

1

0.011

ELS

0.011

EMW

1

0.011

EVM

3

0.033

HAM

1

0.011I

HEM

0.011

Aqing

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

3/1/0

0.033

0.033

0/1/0

0.000

0.000

2/0/0

0.022

0.022

1/0/0 0/0/1 0/1/0

0O.000

0.000

3/U/0 O/l/u O/1/0

O.000

0.000

0.011

0.011

0.011

0.000

0.033

0.033

O.0u 0

0.000
TABLE F-7. (continued)

SYSTEM

ESSENTIAL SERVICE WATER SYSTEM

COMPONENT

MOTOR-DRIVEN PUMPS

Failure Mode: FAILS TO RUN - GFU(continued)

Failure Cause

Failure Cause Code HPM SPM

Failure Cause Count 1 1

Failure Cause Fraction 0.011 0.011

Totals

1 .UUU

71q

Itj

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

0/1/0

0.000

0.000

1/0/0 66/2U/B

0.011

0.011

U.7d1

0.715

Failure Mode: FAILS TO START - GFS

Failure Cause

Failure Cause Code EBF

Failure Cause Count I

Failure Cause Fraction 0.083

Totals

EBR

0

0.083

EOB

4

0.333

EDI

3

0.250

ELC

.

0.083

ELF

3

0.083

EMH

0.083

12

1.UOU

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

1/0/0

0.083

0.083

1/0/0

0.083

0.083

0/0/4

0.333

0.000

1/2/0 1/U/0 0/1/0

0. 000

0.000

O/1/U 4/4/4

0.083

0.083

0.083

0.083

0.MO0

0.000

U. 665

U.j32
TABLE F-S. FAILURE CAUSE TALLIES, FAILURE CAUSE FRACTIONS, ANO AGING FRACTIONS FOR SwS STAMRtkS

SYSTEM

ESSENTIAL SERVICE WATER SYSTEM

COMPONENT

S IRAiN=

Failure Mode: LOSS OF FUNCTION - GLF

Failure Cause

Failure Cause Code EBR

Failure Cause Count 8

Failure Cause Fraction 0.615

Totals

ECC

3

0.231

HAM

1

0.077

HPM

1

0.077

13

1 .uUU

7'

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

8/0/0

0.615

0.615

3/0/0

0.231

0.231

0/1/0

0.000

0.000

0/0/1 1/1/1

0.077

0.000

0.96

U.846

Failure Mode: PLUGGED - GPL

Failure Cause

Failure Cause Code

Failure Cause Count

Failure Cause Fraction

Aginm

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

Totals

EAO

2

0.250

2/0/0

0.250

0.250

EDI

6

0.750

4/2/0

0.500

0.500

8

1.000

6/2/U

0.750

U.75U
TABLE F-9. FAILURE CAUSE TALLIES, FAILURE CAUSE FRACTIONS, ANU AGING FRACTIONS FUR SWS CIRCUIT BREAKERS, AC

SYSTEM

ESSENTIAL SERVICE WATER SYSTEM

COMPONENI

CIRCUIT bREAKERS, AC

Failure Mode: FAILURE TO OPERATE - GFP

Failure Cause

Failure Cause Code EBF

Failure Cause Count 2

Failure Cause Fraction 0.182

ALinm

Totals

EBM

1

0.091

EBR

2

0.182

EDB

2

0.182

EDI

3

0.273

HEM

1

0.091

II

1.00O

.I

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

2/0/0

0.182

0.182

Failure Mode: OPEN (PREMATURE) - GSO

Failure Cause

Failure Cause Code EOB

Failure Cause Count I

0/0/1

0.091

0.000

EDI

1

0.167

2/0/0

0.182

0.182

ELE

1

0.167

1/0/1 3/0/0 O/1/U

0.000

0.000

0.182

0.091

ELW

2

0.333

0.273

0.273

U.9 IU

0.728

8/1/2

Totals

-

SPC

1

0.167 0.167

6

Failure Cause Fraction 1.UUU

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

0/1/0

0.000

0.000

0/1/0

0.000

0.000

0/1/0

0.000

0.000

1/0/1 0/1/0 1/4/1

0.333

0.167

0.000

0.000

U.333

0.167
TABLE F-10. FAILURE CAUSE TALLIES, FAILURE CAUSE FRACTIONS, AND AGING FRACTIONS FOR SWS FLOW INDICATORS

SYSTEM

ESSENTIAL SERVrr=4ATER SYSTEM

COMPONENT

FLOwTNflTCAIRS

Failure Mode: ERRONEOUS/ERRATIC SIGNALS - GEE

Failure Cause

Failure Cause Code ELF

Failure Cause Count I

Failure Cause Fraction 1.000

Totals

1.000

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

0/O/l

1.000

0.000

0/O/1

1.OUO

0.000

Failure Mode: FAILURE TO OPERATE - GFP

Failure Cause

Failure Cause Code EDI

Failure Cause Count I

Failure Cause Fraction 0.250

Aging

Yes/No/Unknown 0/1/0

Aging Fractions

Upper Bound 0.000

Lower Bound 0.000

Totals

ELT _

3

0.750

4

1.uu0

3/0/0 3/1/U

0.750

0.750

0.7bU

0.750
TABLE F-li. FAILURE CAUSE TALLIES, FAILURE CAUSE FRACTIONS, AND AGING FRACTIONS FOR SWS FLOW SWITCHES

SYSTEM

ESSENTIAL SERVICE WATER SYSTEM

COMPONENT

FLO 3SWT S

Failure Mode: ERRONEOUS/ERRATIC SIGNALS - GEE

Failure Cause

Failure Cause Code EDI ELD

Failure Cause Count 1 13

Failure Cause Fraction 0.062 0.812

Aging

Yes/No/Unknown 1/0/0 13/0/0

Aging Fractions

Upper Bound 0.062 0.812

Lower Bound 0.062 0.812

ELI

l

0.062

1/0/0

0.062

0.062

ELT -

1

0.062

1/0/0

0.062

0.062

Totals

16

1 .UUU

I b/u/u

1 .UUU

1.0Q0
TABLE F-12. FAILURE CAUSE TALLIES, FAILURE CAUSE FRACTIONS, AND AGING FRACTIONS FOR SWS PRESSURE INUICATORS

SYSTEM

ESSENTIAL SE iT=WATER SYSTEM

COMPONENT

PRESSURE INDICATORS

Failure Mode: ERRONEOUS/ERRATIC SIGNALS - GEE

Failure Cause

Failure Cause Code EDI EDT

Failure Cause Count 2 2

Failure Cause Fraction 0.400 0.400

Aging

TotaIs

ELT

1

0.200 1 .UUU

71

t'j

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

2/0/0

0.400

0.400

2/0/0 0/0/1 4/U/I

0.400

0.400

0.200

0.000

1.000

0.800

Failure Mode: FAILURE TO OPERATE - GFP

Failure Cause

Failure Cause Code EDT

Failure Cause Count I

Failure Cause Fraction 1.000

Totals

1 .UuU

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

0/0/1 0/U/I

1.000

0.000

I .Uur

0.000
TABLE F-13. FAILURE CAUSE TALLIES, FAILURE CAUSE FRACTIONS, AND AGIHG FRACTIONS FOR UPS CIRCUIT BREAKERS, AC

SYSTEM

INSTRUMENT & UNINTERRUPTIBL77POWER SUPPLY SYSTEM - CLASS IE

COMPONENT

CIRCUIT BREAKERS, AC

Failure Mode: FAILURE TO OPERATE - GFP

Failure Cause

Failure Cause Code EBR

Failure Cause Count I

Failure Cause Fraction 0.200

Aging

Yes/No/Unknown 1/0/0

171 Aging Fractions

00

Upper. Bound 0.200

Lower Bound 0.200

ELE

1

0.200

0/1/0

0.000

0.000

HE -

3

0.600

0/3/0

0.000

0.000

Totals

5

1.OUU

1/4/U

0. 2U0

U.20U
TABLE F-14. FAILURE CAUSE TALLIES, FAILURE CAUSE FRACTIONS, AND AGING FRACTIONS FOR UPS INVERTLRS

SYSTEM

INSTRUMENT & UNINTERRUPTIBLFE POWER SUPPLY SYSTEM - CLASS IE

COMPONENT

INV ERIER

Failure Mode: LOSS OF FUNCTION - GLF

Failure Cause

Failure Cause Code DE

Failure Cause Count S

Failure Cause Fraction 0.079

Aging

Totals

DM

2

0.032

EBR

5

0.079

EDB

2

0.032

EL

2

0.032

ELA

1

0.016

ELD

2

0.032

ELE

9

0.143

ELF

I8

0.286

50

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

0/4/1

0.016

0.000

0/2/0

0.000

0.000

5/0/0

0.079

0.079

0/0/2 1/0/1 O/U/i

0.016

0.000

2/0/0

0.032

0.032

0/8/I

O.ulb

O.000

5/4/9

0.2 2

0.079

0.032

0.000

0.032

0.016

Failure Mode: LOSS OF FUNCTION - GLF(continued)

Failure Cause

Failure Cause Code ELI ELO

Failure Cause Count 2 2

Failure Cause Fraction 0.032 0.032

Totals

ELS

8

0.127

ELT

1

0.016

ELV

1

0.016

HE,

1

0.016

HEM

2

0.032

63

1.OUU

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

2/0/0

0.032

0.032

2/0/0

0.032

0.032

1/3/4

0.079

0.016

0/0/1 0/1/0 0/1/U

0.000

0.000

0/2/0 18/25/20

0.016

0.000

0.000

0.000

0.OU0

0.000

O.bU4

U.28b
TABLE F-15. FAILURE CAUSE TALLIES, FAILURE CAUSE FRACTIONS, AND AGING FRACTIONS FOR DC PUWER BATTERIES

SYSTEM

DC POWER SUPPEr-Y1SEM - CLASS IE

COMPONENT

BATTERIE

Failure Mode: LOSS OF FUNCTION - GLF

Failure Cause

Failure Cause Code OM

Failure Cause Count 3

Failure Cause Fraction 0.300

Totals

EBB

1

0.100

EL ELF ELG ELL

1 1 1 1

0.100 0.100 0.100 0.100

ELS

2

0.200

l1

1.UOU

7T

0

Agi

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

3/0/0

0.300

0.300

0/0/1

0.100

0.000

0/0/1

0.100

0.000

0/0/1 1/0/0 1 /U/U o/0/2

0.100

0.000

0.100

0.100

0.100

0.100

0.200

0.000

1.000

0.500
TABLE F-16. FAILURE CAUSE TALLIES, FAILURE CAUSE FRACTIONS, AND AGINb FRCIIUtNS FOR DC POWLk BATTLRY CmAkbING UNIT

SYSTEM

DC POWER SUPPLY SYSTEM - CLASS 1E

COMPONENT

BATTERY CHARGINU UNITS

Failure Mode: LOSS OF FUNCTION - GLF

Failure Cause

Failure Cause Code EBR

Failure Cause Count 1

Failure Cause Fraction 0.029

Totals

EDB

2

0.057

EDI

1

0.029

EL

3

0.086

ELA

1

0.029

ELD

1

0.029

ELF

23

0.657

ELO

1

0.029

ELR

1

0.029

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

1/0/0

0.029

0.029

0/0/2

0.057

0.000

1/0/0

0.029

0.029

1/0/2 0/0/1 I /U00

0.029

0.029

14/0/9 0/U/1 O/l/U

O.000

U.000

0.086

0.029

0.029

0.000

0.657

0.400

0.u29

0.000

Failure Mode: LOSS OF FUNCTION - GLF(continued)

Failure Cause

Failure Cause Code ELS

Failure Cause Count 1

Failure Cause Fraction 0.029

Aging

Yes/No/Unknown 0/0/1

Aging Fractions

Upper Bound 0.029

Lower Bound 0.000

Totals

35

1.000

18/1/l6

0.974

u.516
TABLE F-17. FAILURE CAUSE TALLIES, FAILURE CAUSE FRACTIONS, AND AGING FRACTIONS FOR EMERGENCY POWER CIRCUIT BkEArERS

SYSTEM

EMERGENCY ON-SITE POWER SUPPLY SYSTEM

COMPONENT

CIRCUIfMEAERS, AC

Failure Mode: FAILURE TO OPERATE - GFP

Failure Cause

Failure Cause Code EBR

Failure Cause Count 2

Failure Cause Fraction 0.400

Totals

71

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

EDB

3

0.600

0/0/3

0.600

0.000

2/0/0

0.400

0.400

2/u/3

5

1.UUU

I.UUO

0.400
TABLE F-18. FAILURE CAUSE TALLIES, FAILURE CAUSE FRACTIONS, ANU AGING FRACTIONS FOR ENLRGENLY POWER DItSEL GENERATOR

SYSTEM

EMERGENCY ON-SITE POWER SUPPLY SYSTEM

COMPONENT

DIESEL GENERATORS

Failure Mode: FAILS TO START - GFS

Failure Cause

Failure Cause Code DEI

Failure Cause Count 2

Failure Cause Fraction 0.111

Aging

Totals

EBR

2

0.111

EOB

3

0.167

EDI

3

0.167

EEN

1

0.056

EL

2

0.111

ELF

1

0.056

ELR ELT

1 1

0.056 0.056

7,J

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

2/0/0

0.111

0.111

2/0/0 0/1/2 2/1/0 0/1/0 0/2/U

0.000

O.OOU

1/0/0

0.056

0.056

0/1/0

0.000

0.OOU

0/1/0

0.000

0.000

0.111

0.111

0.111

0.000

0.111

0.111

0.000

0.000

Failure Mode: FAILS TO START - GFS(continued)

Failure Cause

Failure Cause Code EMW

Failure Cause Count 2

Failure Cause Fraction 0.111

Totals

18

1.000

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

0/2/0 7/9/2

0.000

0.000

0.500

0.389
TABLE F-18. (continued)

SYSTEM

EMERGENCY ON-SITE POWER SUPPLY SYSTEM

COMPONENT

DIESEL GENERATORS

Failure Mode: FAILS TO RUN - GFU

Failure Cause

Failure Cause Code OEI

Failure Cause Count I

Failure Cause Fraction 0.022

Totals

EBB

2

0.043

EBF

01

0.022

EBM

2

0.022

EBR

14

0.304

EDB

4

0.087

EDI

3

0.065

EUU

2

0.043

EL

1

U.022

7I

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

0/1/0

0.000

0.000

2/0/0

0.043

0.043

110/0

0.022

0.022

0/0/1 14/0/U 1/2/1

0.043

0.022

2/l/U

0.043

0.043

2/U/U

0.043

0.043

U/i/1

O.ud2

0.000

0.022

0.000

0.304

0.304

Failure Mode: FAILS TO RUN - GFU(continued)

Failure Cause

Failure Cause Code ELD ELE

Failure Cause Count 5 2

Failure Cause Fraction 0.109 0.043

Totals

ELF

3

0.065

ELO

1

0.022

ELS

3

0.065

EVM

1

0.022

HEM

1

0.022

SPC

l

0.022

40

1 .uUU

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

5/0/0

0.109

0.109

0/2/U

0.000

0.000

2/U/1

0.065

0.043

0/0/1 2/0/1 1 /O/U

O.U22

O.U22

0/1/U

O.OOU

0.000

Ol/u

0.022

0.000

0.065

0.043

O.OUU

O.U0U

U.8eb

j. 6V4
TABLE F-18. (continued)

SYS1EM

EMERGENCY ON-SITEPOWER SUPPLY SYSTEM

COMPONENT

DIESEL GENEWATORS

Failure Mode: NO FAILURE - GNF

Failure Cause

Failure Cause Code DE

Failure Cause Count 1

Failure Cause Fraction 0.020

Totals

OM

2

0.041

EBB

2

0.041

EBF

5

0.102

EBR

6

0.122

ECC

1

0.020

EDB

4

0.082

EDI

2

0.041

EUU

1

0.020

Yes/No/Unknown 0/1/0 0/1/1 2/0/0 5/0/0 6/0/0 1/0/0 1/0/3 2/0/0 0/1/0

I71 Aging Fractions

Upper Bound

Lower Bound

0.000

0.000

0.020

0.000

0.041

0.041

0.102

0.102

0.122

0.122

0.020

0.020

0.082

0.020

0.041

0.041

0.000

0.000

Failure Mode: NO FAILURE - GNF(continued)

Failure Cause

Failure Cause Code EDS EDU

Failure Cause Count 1 1

Failure Cause Fraction 0.020 0.020

Totals

EL

2

0.041

ELD

1

0.020

ELF

1

0.020

ELU

1

0.020

ELT

3

0.061

ELW

1

0.020

i EMW

0.184

Aging

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

1/0/0

0.020

0.020

1/0/0 0/0/2 1/0/0 0/0/1 1/0/0

0.020

0.020

1/0/2

0.061

0.020

O/U/1

0.020

0.0UO

2/6/1

O.U61

0.041

0.020

0.020

0.041

0.000

0.020

0.020

0.020

0.000
TABLE F-18. (continued)

SYSTEM

EMERGENCY ON-SIOE POWER SUPPLY SYSTEM

COMPONENT

DIESEL GENETRATORS

Failure Mode: NO FAILURE - GNF(continued)

Failure Cause

Failure Cause Code EPL EVM

Failure Cause Count 1 3

Failure Cause Fraction 0.020 0.061

Totals

- HEM

0.020

* 49

I .uuu

o1

W~

ALing

Yes/No/Unknown

Aging Fractions

Upper Bound

Lower Bound

0/1/0

0.000

0.000

3/0/0

0.061

0.061

0/0/1

0.020

0.000

0.792

U.548
TABLE F-19. FAILURE CAUSE TALLIES FOR SYSTEM EFFECTa

System

Essential Service Water System

System Effect

Degraded System Operations

Component

Circuit Breaker, AC

--I

Temperature Control Indicator

Flow Indicator

Motor

Pipe

Motor-Driven Pump

Relay

Overcurrent Relay (DC)

Strainer

Flow Switch

Differential Pressure Switch

Pressure Switch

Check Valve

Hand Control Valve

Motor-Operated Valve

Countb

1

I

I

1

2

2

1

1

10

2

1

2

2

7

2

2

Failure

Cause

EBR

EDB

EDI

HEM

EDB

ELT

ELC

EBE

ECC

EBR

EDB

EDI

El

EVM

HAM

HPM

SPM

SPO

DE

ELO

EDI

HAM

ELD

ELI

ELT

EDI

EDI

ELD

EBE

EBR

EBR

ECC

HEM

HEO

DCI

DEI

DM

EBR

ECC

EDB

EDI

ELE

ELH

ELK

ELO
TABLE F-19. (continued)

System System Effect Component

Essential Service Water

(continued)

Degraded System Operation

(continued)

Motor-Operated Valve

(continued)

Pneumatic-Operated Valve

Relief Valve

System Function/Operations Circuit Breaker, AC

Unaffected

00

Flow Indicator

Pressure Indicator

Temperature Indicator

Zone Modifier

Motor-Driven Pump

Relay

Snubber

Strainer

Flow Switch

Differential Pressure Switch

Level Switch

Position-Limit Switch

Level Transmitter

Countb I642322253222323

10

2°1

Failure

Cause

ELR

ELS

EMW

EBR

EDB

EDI

ELD

EVM

EBE

EBR

EDI

ELE

ELF

ELT

EDI

EDT

ELT

ELT

EDB

DC

EBB

EBE

EBF

EBR

ECC

EDB

EDI

EDU

ELC

EMW

EVM

HEM

SPM

EBR

DCI

ECC

EBR

ECC

EDI

ELD

ELD

EMW

EBR

EDI
TABLE F-19. (continued)

System

Essential Service Water

(continued)

System Effect

System Function/Operation

Unaffected (continued)

Component

Check Valve

Hand Control Valve

Motor-Operated Valve

Pneumatic-Operated Valve

Vent Valve

Countb 23322

1212221212921

Failure

Cause

EBE

EBR

ECC

EDB

EDI

HPM

EBE

EBR

ECC

HEO

DC

EBE

EBF

EBR

ECC

EDB

EDI

EDU

EL

ELE

ELK

ELO

ELT

HEM

HEO

HPM

EBB

EBF

EBR

ECC

EDB

EDI

EDU

EVM

HA

EBE

EDB

EBM

EDB

EDI

EDI

ELD

ELS

ELE

Loss of Redundancy Circuit Breaker, AC

Differential Pressure Control

Recorder

Flow Indicator

Flow Modifier

Motor

Electric Power Supply
TABLE F-19. (continued)

System

Essential Service Water

(continued)

System Effect

Loss of Redundancy (continued)

Component

Motor-Driven Pump

7'

09~

Relay

Strainer

Pressure Switch

Check Valve

Hand Control Valve

Motor-Operated Valve

Pneumatic-Operated Valve

Count 3

16412114

121112425222

Failure

Cause

DM

EAO

EBF

EBR

ECC

EDB

EDI

EDU

ELF

ELI

ELS

EMH

EVM

ELC

EBR

ECC

EL

DCI

DE

EBR

ECC

ECC

EDB

EDI

EBR

EDB

EL

ELO

EMW

ECC

EDB

EDI

EBF

EDI

ELW

SPC

EBR

EDI

EDT

EDI

ECC

EMI

DCI

Loss of Subsystem/Channel Circuit Breaker, AC

Differential Pressure Control

Recorder

Pressure Indicator

Motor

Pipe

Motor-Driven Pump
TABLE F-l9. (continued)

System

Essential Service Water

(continued)

System Effect

Loss of Subsystem/Channel

(continued)

Component

Motor-Driven Pump (continued)

Snubber

Strainer

Support

Flow Switch

Differential Pressure Switch

Temperature Switch

Thermowell

Check Valve

Hand Control Valve

Motor-Operated Valve

Pneumatic-Operated Valve

Relief Valve

Safety/Relief Valve

Countb

252

15225333321123433

Failure

Cause

EBE

EBR

ECC

EDI

ELI

EL0

EVM

HAM

HEO D

EDI

EAO

EBR

ECC

EDI

HPM

DEI

EBR

EDI

EBR

ELT

ECC

EBR

ECC

ECC

EDB

EBE

EBR

ECC

EDB

EDI

EDU

EL

ELO

ELS

EMW

EVM

HEM

HEO

EBR

EDB

EDI

EVM

EBR

EDI

EDB
TABLE F-19. (continued)

System

Medium-Voltage Power System--Class IE

System Effect

Degraded System Operations

System Function/Operations

Unaffected

Loss of Redundancy

Loss of Subsystem/Channel

Component

Cable

Circuit Breaker, AC

Transformer

Circuit Breaker, AC

Transformer

Circuit Breaker, AC

Circuit Breaker, AC

Transformer

Countb

I

Low-Voltage Power System--Class lE Degraded System Operations

System Function/Operations

Unaffected

Loss of Redundancy

Loss of Subsystem/Channel

Degraded System Operations

71I

4'J

Instrument & Uninterruptible

Power System--Class lE

Circuit Breaker, AC

Circuit Breaker, AC

Relay

Bus

Relay

Circuit Breaker, AC

Inverter

Inverter

2

3

3

2

4

1

Failure

Cause

ELI

ELE

ELI

HPM

EBR

HPM

ELC

EMW

HEM

ELO

ELT

SPC

HEM

DEI

ELS

HE

DE

EBR

ELD

ELE

ELF

ELO

ELS

HE

HEM

EBR

EDB

ELD

ELE

ELF

ELI

ELO

ELS

ELT

System Function/Operations

Unaffected

3

1

3

7
TABLE F-19. (continued)

System

Instrument & Uninterruptible

Power System--Class IE

(continued)

System Effect

Loss of Redundancy

Loss of System Function

Loss of Subsystem/Channel

Component

Circuit Breaker, AC

Inverter

Inverter

Circuit Breaker, AC

Inverter

Battery

Battery Charger

Circuit Breaker, AC

Battery

tJJ1

Countb 121l1341124211261112

Failure

Cause

ELE

DE

DM

EBR

ELA

ELE

ELF

ELI

ELS

DE

ELF

EBR

DE

EDB

EL

ELF

ELS

ELV

HEM

ELL

EDI

EL

ELD

ELF

ELS

ELL

DM

EL

ELF

ELG

ELS

EDB

ELA

ELF

ELR

EBR

ELF

ELO

DC Power System--Class IE Degraded System Operations

System Function/Operations

Unaffected

Battery Charger

Loss of Redundancy Battery Charger

9l1
TABLE F-19. (continued)

System

DC Power System--Class IE

(continued)

Emergency On-Site Power

Supply System

System Effect

Loss of Subsystem/Channel

Degraded System Operations

Component

Battery

Battery Charger

Countb 1116

Circuit Breaker, AC

Diesel Generator

System Function/Operations

Unaffected

Loss of Redundancy

Diesel Generator

Temperature Indicator

Circuit Breaker, AC

Diesel Generator

3264221322233226

Failure

Cause

EBB

ELS

EDB

EL

ELF

EBR

EDB

EBB

EBF

EBR

EDB

EDI

EDO

EDU

ELD

ELF

ELR

ELS

ELT

ELW

EMW

EPL

DE

EBB

EBM

EBR

EDB

EDI

EOU

EL

ELD

ELF

EVM

SPC

EDB

EBR

DEI

DM

EBR

EDB

EDI

EDU

EEN
TABLE F-l9. (continued)

System

Emergency On-Site Power

Supply System (continued)

System Effect

Loss of Redundancy (continued)

Component

Diesel Generator (continued)

Diesel Generator Loss of Subsystem/Channel

Count

2

l

4l

1

1

5

3

1

2

3

1

1

2

1

2

2

2

2

1

Failure

Cause

EL

ELD

ELE

EMW

EVM

DEI

EBB

EBF

EBR

ECC

EDB

EDT

EDS

EL

ELD

ELE

ELO

ELS

ELT

EMW

HEM

EBR Timer

a. Table summary does not contain data for any failure categorized unclassified (Table F-20).

b. Total counts: 732.
TABLE F-20. SUMMARY OF RECORDS IN WHICH THE FAILURE CAUSE WAS UNCLASSIFIABLE

System Component

Circuit Breaker, AC

Failure Mode System Effect

Essential Service Water System Fails to Operate Degraded System Operations

gi ng Counts

hO 1

UNK 1

Pressure Switch UNK 1

Flow Switch

Check Valve

Fails to Operate

Erroneous/Erratic Signals

Internal Leakage

Degraded System Operations

Hanger

Hand Control Valve

Motor-Driven Pump

Loss of Function

Fails to Open

Failure to Operate as Requires

External Leakage

Fails to Start

Fails to Run

Loss of Redundancy

Degraded System Operations System Function Unaffected

Loss of Subsystem/Channel

Loss of Sunsystem/Lhannel

System Function Unaffected

Degraded System Operations

System Function Unaffected

Loss of Redundancy

Loss of Subsystem/Channel

Loss of Redundancy

Liegraoed System Operations

System Function Unaffectea

UNK

UNK

UNK

UNK 3

1

2

UNK

UNK l

YLS

YES

YES

YES

UNK

YES

[tu

UNK

YES

YES

UNK

NE

YES

1

2

I

1

1

3 Loss of

Loss of

Loss of

Redundancy

System Function

Subsystem/Channel

Motor-Operated Valve External Leakage

Fails to Close

Fails to Open

Failure to Operate as Required

Fails to Open/Fails to Close

System Function Unaffectea

Degraded System Operations

System Function Unaffected

Loss of Redundancy

Degraded System Operations

System Function Unaffected

Loss of Redundancy Loss of Suosystem/Channel Degraded System Operations System Function Unaffected

Loss of Suusystem/Channel

Degraded System Operations

System Function Unaffected

Loss of Redundancy

Loss of Subsystem/Channel

UNK

NO

YES

UhK

YES

UhK

UhK

UNK

UNK

YES

YES

UNK

UNK

UNK

UNK

'ID

I

2

1

2

1.
TABLE F-20. (continued)

System

Essential Service Water System

(continued)

Component

Pneumatic-Operated

Valve

Failure Mode

External Leakage

Fails to Close

Fails to Open

Failure to Operate as Required

Fails to Open/Fails to Close

Strainer

-17

Medium-Voltage Power

System--Class IE

Low-Voltage Power

System--Class lE

Instrument & Uninterruptible

DC Power System--Class IE

Emergency On-Site Power

System--Class 1E

Transformer

Circuit Breaker, AC

Bus

Inverter

Battery

Battery Charger

Diesel Generator

Loss of Function

Loss of Function

Fails to Operate

Loss of Function

Loss of Function

Loss of Function

Loss of Function

Fails to Start

Fails to Run

System Effect

System Function Unaffected

Degraded System Operations

System Function Unaffected

Loss of Subsystem/Channel

Degraded System Operations

System Function Unaffecteo

Loss of Redundancy

Loss of Subsystem/Channel

Degraded System Operations

Loss of Redundancy

Loss of Subsystem/Channel

Degraded System Operations

Loss of Subsystem/Channel

Degraded System Operations

System Function Unaffected

Loss of Subsystem/Channel

System Function Unaffected

Degraded System Operations

System Function Unaffected

Loss of Subsystem/Channel

System Function Unaffected

Degraded System Operations

Loss of Redundancy

Loss of Subsystem/Channel

Degraded System Operations

System Function Unaffected

Loss of Redundancy

Loss of Subsystem/Channel

Aging

YES

YES

UNK

YES

NO

UNK

YES

YES

UNK

YES

UNK

UNK

UNK

NO

UNK

UNK

YES

NO

UNK

NO

UNK

UNK

YES

UNK

UNK

YES

Nh

YES

NU

UNK

UNK

NO

UNK

YES

UNK

YES

UNK

YES

NO

Counts

2

2

12

2

2

2

l

3

1

2

2

S

l

3

12

2
TABLE F-20. (continued)

System Component Failure Mode System Effect Aging Couiits

Emergency On-Site Power Diesel Generator No Failure Degraded System Operations NO l

System--Class lE (continued) (continued) UiK l

YES 1

System Function Unaffected UNK 2

Loss of Redundancy UNK 2

Loss of Subsystem/Channel UNK I

YES I

Temperature Indicator Erroneous/Erratic Signals System Function Unaffected YES I

71

00
NPC FORP K US. aUCLIAR REGULATORY COMISSION1 I REPORT NUMBER IA.,. *V riDC. dd V.I N., ,pI

12-141

3201.3202. BIBLIOGRAPHIC DATA SHEET

SEE INSTRUCTIONS ON THE REVERSE

2 TITLE AND SUBTITLE J LEAVE BLANK

An Aging Failure Survey of Light Water Reactor

Safety Systems and Components 4 DATE REPORT COMPLETED

Volume 1 MONTH I VEAR

5 AUTOORISI July 1987 1987

Babette M. Meale; David G. Satterwhite MONTH TEREOTSSUEDAR

July 1987

7 PERFORMING ORGANIZATION NAME ANoP MAILING AOORESE I)PV- 1 S. PROJSCTITASIEIWORK UNIT NUMBER

EG&G Idaho, Inc.

Idaho Falls, ID 83415 SPIN OR GRT J"{t

A6389

IS. SPONSORING ORGANIZATION NAME ANO MAILING ADORESS II.,M ZIP Cp.)I I.. TYPE OF REPORT

U.S. Nuclear Regulatory Cornmmission Research

Washington, D. C. 20555 R PEIIODCOVERIOI I.V..1fi

12 SUPPLEMENTARY NOTES

Ii ABSTRACT (ads', '.0

This report describes the methods, analyses, results, and conclusions of two different aging studies. The first analysis consists of a survey of light water reactor component failures associated with selected safety and support systems. Tables are

presented, indicating the systems and the components within those systems most

affected by aging. Also provided are engineering insights drawn from the data. The

second analysis consists of identifying and categorizing the reported failure causes of

component failures. The systems used in the failure-cause analysis were service water

systems and Class IE electrical power distribution systems for Babcock & Wilcox

Company pressurized water reactors and service water systems for boiling water

reactors.

O DOCUME'T ANALISIS , KYOR1OSOESCFI1TOHS IS AVAILABILITY

STATEMENT

re SCURITY CLASSIFICArION

b IOENTIFIERS,OPeN ENODE TERMS Uncl.

IT*,,, ,fJ

Uncl. I7. NUMBER OF PAGES

163 .~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~I 7 RICE

-~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~~~~~~~~~ 4

91;a hr.

Wa Faut Wash

AIF