Text

Forwards High Energy Line Break/Control Sys Failure Analysis, Which Demonstrates Consequences of Postulated High Energy Line Breaks & Effects on nonsafety-related Control Sys Components.Related Correspondence
	ML20084J614
Person / Time
Site:	Limerick
Issue date:	05/09/1984
From:	Kemper J; PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Schwencer A; Office of Nuclear Reactor Regulation
References
	RTR-NUREG-0991, RTR-NUREG-991 OL, NUDOCS 8405090161
	Download: ML20084J614 (80)
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                                                                      @TED CORRESPONDENCE c55 PHil.ADELPHIA ELECTRIC COMPANY 2301 MARKET STREET P.O. BOX 8699              OggqED PHILADELPHIA, PA.19101    MAY - 41984
         . .... ..                                  tam m so:            '84 MY -9 A10:37 VICE#REllOENT Csetsataneses ases nestascu Mr. A. Schwencer, Chief            .                Docket hhk5h2,"d.Od Licensing Branch No. 2 Division of Licensing B608353   g U. S. Nuclear Regulatory Commission Washington, D.C. 20555

Subject:

Limerick Generating Station, Units 1&2 SER Open Issue Thirteen

Reference:

Limerick Safety Evaluation Report (NUREG-0991) File: , GOVT 1-1 (NRC)

Dear Mr. Schwencer:

Open issue thirteen of the reference requested Philadelphia Electric to evaluate the effects and consequences of a high energy line_ break (HELB) to verify that when the safety systems respond to mitigate the effects of the HELB, a single active failure in the safety systems in conjunction with all possible combinations of control systems and nonqualified safety systems failures induced by the HELB are bounded by the Limerick FSAR Chapter 15 analyses. Enclosed is a copy of our report, High Energy Line Break / Control Systems Failure Analysi_s, which demonstrates that the consequences of postulated high energy line breaks and their effects on adjacent, non-safety-related control systems components are bounded by Limerick FSAR Chapter 15 analysis. Sincerely, 8405090161 840509 DR ADOCK 05000 5 . JLP/gra/032384115 cc: See Attache: Service List b dM I : 1

cc: Judge Iawrence Brenner (w/ enclosure) Judge Richard F. Cole (w/ enclosure) Troy B. Conner, Jr., Esq. (w/ enclosure) Ann P. N n, Esq. (w/ enclosure) Mr. Frank R. Romano (w/ enclosure) Mr. Robert L. Anthony (w/ enclosure) Charles W. Elliot, Esq. (w/ enclosure) Sori G. Ferkin, Esq. -(w/ enclosure) Mr. Thcznas Gerusky (w/ enclosure) Director, Penna. Dnergency (w/ enclosure) Managenent Agency Angus R. Iove, Esq. (w/ enclosure) David Warsan, Esq. (w/ enclosure) Robert J. Sugaman, Esq. (w/ enclosure) Spence W. Perry, Esq. (w/ enclosure) Jay M. Gutierrez, Esq. (w/ enclosure) Atcznic Safety & Licensing (w/ enclosure,) Appeal Board Atcznic Safety & Licensing (w/ enclosure) Board Panel Docket & Service Section (w/ enclosure) Martha W. Bush, Esq. (w/ enclosure) - Mr. James Wiggihs (w/ enclosure) Mr. Tinothy R. S. Canpbell (w/ enclosure) Ms. Phyllis Zitzer (w/ enclosure) Judge Peter A. Morris (w/ enclosure) 9 a

4-HIGH ENERGY LINE BREAK / CONTROL SYSTEMS FAILURE ANALYSIS

           ,,             REPORT ON LIMERICK GENERATING STATION UNIT 1 PREPARED FOR PHILADELPHIA ELECTRIC COMPANY PREPARED BY R. K. SCHROEDER        E. D. SCHRULL     R. W. STRONG GENERAL ELECTRIC COMPANY NUCLEAR ENERGY BUSINESS OPERATION SAN JOSE, CALIFORNIA -

APRIL 1984 12-1479 (1) . (

O

o. .

This report was prepared by the General Electric Company (GE) for the Philadel-phia Electric Company (PECO). A significant technical contribution to the report was made by Bechtel Power Corporation (BPC). j This report has been reviewed and approved by: b . S. H. Slivinsky, Technical cader, Regulatory Compliance Engineering Nuclear control and Instrumentation Product Design Operation h M. A. Smith, Manager, Regulatory Compliance Engineering Nuclear Control and Instrumentation Product Design Operation 2: C. E. C. Eckert, Manager, Plant Transient Performance Engineering Nuclear Power Systems Engineering Department i R. R. Bloom (trand, Senior Licensing Engineer, Project Licensing Nuclear Safety and Licensing Operation t a 12-1479 (2)

O I

1.0 INTRODUCTION

Page 1.1 Purpose 1-1 1.2 Scope of Study 1-1 1.3 Summary of Results 1-1 2.0 METHODOLOGY 2.1 System Elimination 2-1 2.2 Component Elimination 2-3 2.3 High Energy Pipe Criteria 2-4 2.4 Zone Determination 2-7 2.5 Pipe Break Location and Effects 2-8 4 2.6 Plant Walkdown 2-9 2.7 Zone Analysis 2-10

3.0 CONCLUSION

S AND RECOMMENDATIONS 3-1

4.0 REFERENCES

4-1 APPENDIX A - ANALYSIS

SUMMARY

A-1 APPENDIX B - FIGURES B-1 l l 12-1479 (3)

                       ,     ,             _ _ . , _ , . , - - ~ - - -- av-- ' * * ' - - ' '    ' ' " ' - ~ ' ' ' " ' ' " " ~ "

1.0 INTRODUCTION

1.1 PURPOSE The purpose of this study was to determine the effects of a High Energy Line Break (ELB) on any non-safety-related control systems in , Limerick Generating Station Unit 1. In particular, the purpose was to determine whether any adverse effects initiated by a ELB could result in an event more severe than the transient and accident events analyzed in Chapter 15 of the Limerick Generating Station Final Safety Analysis Report (FSAR). The analyr's presented in this report responds to the IE Information Notice 79-22, as published by the NRC in September 1979. 1.2 SCOPE OF STUDY The scope of this ELB analysis was restricted to high energy pipe , breaks and their effects on components of non-safety-related control systems at Limerick Generating Station Unit 1. A computerized list of all plant components was reduced based on the system elimination criteria presented in Section 2.1 and further reduced by using the component elimination criteria of Section 2.2. The basis for consi-dering a line as being "high energy" and the effects of postulated pipe ruptures are detailed in Sections 2.3 and 2.5, respectively. Zones containing both control systems components of interest and high energy lines were defined (Section 2.4) using the appropriate drawings and verified during a plant walkdown (Section 2.6). The effects of postulated pipe ruptures were also assessed during the walkdown. A ELB zone analysis was performed (Section 2.7) and the results summar-ized in Appendix A. . Final conclusions and recommendations are presented in Sec, tion 3.0. 1.3

SUMMARY

OF RESULTS A comprehensive, systematic study has been conducted to determine the , consequences of postulated high energy line breaks and their effects

           .                               on adjacent, non-safety-related, control systems components.                                            The Analysis Summary (Appendix A) describes each of the postulated ELB

. events and their limiting effects on the reactor parameters. In most l cases, the effects of the postulated HELB/ control systems failures events are less severe than the Unacceptable Results for Incidents of Moderate Frequency - Anticipated Operational Transients presented in FSAR Chapter 15. In all cases, the effects of the postulated events i are bounded by the Unacceptable Results for Limiting Faults - Design i Basis (Postulated) Accidents presented in FSAR Chapter 15. It is i concluded that safe reactor shutdown is assured for all events postu-lated herein, and the consequences of these postulated events do not result in any significant risk to the health and safety of the public. ' l l 12-1480 1-1 __ _ -- _ . _ _ . _ _ __.________.____.__.m.____._.__._,._._

i . 2.0 METHODOLOGY The methodology contains criteria, . assumptions , and a scope of work developed to be consistent with the intent of IE Information Notice 79-22. The procedure followed was to: 3

1. Identify any non-safety control systems and components within these systems which could impact the critical reactor parameters (e.g. water level, pressure, critical power ratio);

2. Establish assumptions and criteria for identification of high j , energy lines, location of postulated breaks, and evaluation of j consequences;

3. Identify the locations (area / elevation / room), referred to as zones, containing both high. energy lines and control systems components determined in 1. above; 1

4. Perform a plant walkdown to verify the location of the . control systems components and their proximity to high energy lines;

! 5. Postulate pipe breaks in the zones defined and determine which j control systems components are affected by each possible pipe l break; L 6. Analyze the potential effects on the control systems components impacted and determine the effects on any controlled components; i

7. Combine the effects of the HELB with potential, simultaneous malfunctions of adjacent control systems components and determine the effects on the critical reactor parameters;

8. Compare the effects with the transient and accident analyses in i

Chapter 15 of the FSAR, considering sa additional single active component failure. l . 9. Identify postulated events that are beyond Chapter 15 analyses

!                                                          and recommend corrective actions.

2.1 SYSTEM ELIMINATION The scope of this HELB analysis was restricted to non-safety-related control systems components. Safety systems and safety-related compon-ents of control systems were eliminated from consideration. The effects of piping failures on safety-related equipment are documented in FSAR 3.6. The criteria for further eliminating systems from the detailed HELB analysis are listed below. These criteria were applied to a complete list of plant systems provided by Bechtel Power Corpora-- tion (BPC). l 1. Non-electrical systems, i.e., mechanical and structural systems comprised only of structural steel, piping, tanks, cranes, and l like equipment are excluded. 1481 2-1

          .-- -                               -.  . .                      .                                   -          . - ~ . _ - - -

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                                                           -r f

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i . , 1

2. Inststtaentation sycteas with no direct or indirect controlling fanction (i.e, systems which provide monitoring, status, and alara indications only) are excluded.

                                                                                           .               Instrumentation and              i
                                                 -dedicated inputs -iuts the process computer, as well as the                               '

process computer itsG t, are excluded. i 3. Contrt,1 systems which have no direct or indirect interaction with l reactor operation or reactor parameters are excluded. Examples are communication, lighting, and external building ventilation j systems.

4. Control syste: cs that interact or interface with the reactor; operating systems directly, but which cannot affect the critical i reactor parameters either directly or indirectly in the short ters are excluded. Systems which can only indirectly affect the j reacter parameters through long term effects (such as water t j quality) are excluded. An example is the Condensate Filter /

l Demineralizer System. The effects of failures in these systems i will surface slowly in comparison to the dynamic effects associ- ) ated with a HELB event. l 5. Systems not used during normal operation in the "Startup" or Run"

modes are excInded. Nortsal plant conditions also include opera- !

l tion in the " Refuel" and " Shutdown" modes, however, the fact that ! l there are no high energy lines with the plant operating in these

modes precludes the possibility of a EELB event, i f
6. Electrical systems involved in power generation and distribution, (

the loss of which will not impact the reactor parameters or l

;                                                 srfety system performance (e.g., the station auxiliary trans-j                                                  formers), are excluded.

! The following list details control systems not eliminated via the i above criteria. These were included in the EELB analysis. Any systems : ! which could possibly be eliminated, but were questionable, were r l retained for analysis purposes. l 1

MPL System

! B21 Nuclear Boiler Process Instrumentation l B21 Steam Leak Detection l C11 Control Rod Drive / Reactor Manual control ; D12 Process Radiation Monitoring ! D22 Area Radiation Mor.itoring

I C32 Feedwater Control *

) 832 Reactor Recirculation / Jet Pump Instrumentation C51 Neutron tfonitoring . l G31 Beactor Water Cleanup Mol Main Steam M02 Estraction Steam N05 Condensate M06 Feedwater - M09 Circulating Water i i 12-1441 2-2 A ,. _ _ _ . _ _ _ . _ . _ _ _ _ _ - . _ _ ~ _ _ _ .

i ) { M10 Service Water M12 RHR Service Water , M13 Reactor Enclosure Cooling Water M14 Turbine Enclosure Cooling Water i MI5 Compressed Air l M19 Lube 011 ! M25 Plant Leak Detection j M26 Plant Process Radiation Monitoring j M28 Generator H Cooling and CO Purge i M57 Containment Atmospheric Control j M59 Primary. Containment Instrument Gas i M75 Turbine Enclosure HVAC i M76 Reactor Enclosure HVAC Drywell HVAC M77 j M78 Control Enclosure HVAC i .. M79 Radwaste Enclosure HVAC M87 Drywell Chilled Water Turbine Control Systems Main Turbine Generator System Turbine Bypass System 1 ! 2.2 COMPONENT ELIMINATION l The computerized list of all plant components (References 1 and 2) was ! reduced not only by system but also on a component basis. The follow- { ing elimination criteria were applied to the remaining components to j arrive at the final list of components considered in the detailed HELB ,

analysis. The appropriate system Piping and Instrumentation Diagrams
and Elementary Diagrams were used to aid in this elimination. !

l . j 1. Mechanical components (e.g., structural steel, tanks, pipes,

valves) are not considered control system components subject to
failure. However, instrument taps, tubing, and control compon-

!                                                                       ents not excluded via these component elimination criteria which i                                                                        may be physically located on mechanical components, are included.

j . 2. Instruments and other dedicated inputs to the process computer are eliminated. 1

3. Components which provide position status information only, and do not perform any control function, are eliminated. This includes position switches on air and motor operated valves which are not j interlocked with other equipment.

j 4. Components which provide indication'and/or inputs for alarms or recording devices only, are eliminated.

In general, " initiating" type contro'1 components such as elements,

! switches, transmitters, controllers, and converters were included in i the detailed HELB analysis, along with their related taps and process i tubing. Switchgear and Motor Control Centers (MCC) were included as components ; subject to failure, and control systems components supplied by the ) i 12-1441 2-3

     =                -                .-.                       --. -...,            - - ,-            .-.--.-_.---.-.-.a-                          =

1 affected switchgear and MCC were analyzed for loss of power as l necessary. ' 2.3 HIGH ENERGY PIPE CRITERIA The criteria for determining high energy lines used in this study are based on criteria established in Reference 3 and Section 3.6.3 of the Limerick Generating Station FSAR. High energy piping is defined as including those fluid systems that, during normal plant conditions, are either in operation or maintained pressurized under conditions where either or both of the following are met: 1

a. Maximum operating temperature exceeds 200*F. l l

b. Maximum operating pressure exceeds 275 psig. l Those lines that operate above these limits for less than 2% of the time they are required to perform their intended function are classi-fied as moderate energy lines and are therefore excluded from the scope of this study. Piping whose diameter is 1 inch HTS or smaller is also excluded.

The following table details the list of high energy piping systems in which breaks were postulated as the HELB initiating event. This table is consistent with the high energy piping systems defined in Sec-tion 3.6.1 of the Limerick Generating Station FSAR. 1 1 4 l l 12-1481 2-4

           ._.     -. -        _ , ~ . . _ . . . . _ _-- _.               ~__     . _ . . . . ._.. . . _ . _ _ . . . . _ .

HELB ANALYSIS - INITIATING HIGH ENERGY PIPING SYSTEMS FLUID SYSTEM EXTENT OF HIGH ENERGY PIPING Reactor-Recirculation From reactor vessel suction nozzle to recir-culation pump to reactor vessel discharge nozzles Main Steam From reactor vessel nozzles to high pressure turbine and bypass valve manifold; from high pressure turbine through moisture separators to low pressure turbine and condenser inlet valves Feedwater From condensate filter /demineralizers through feedwater heaters and feedwater pumps to reactor vessel nozzles Condensate From condensate pump discharge through steam jet air ejector condenser, steam packing exhauster, and condensate filter /demineral-izers Reactor Water Cleanup From shutdown cooling suction line through 4 1 RWCU pumps, regenerative and nonregenerative heat exchangers, and cleanup filter /deminer-alizers to feedwater lines-l Reactor Vessel Drain From reactor vessel bottom head nozzle to reactor water cleanup line inside primary containment HPCI Steam Supply From main steam line "C" to HPCI turbine steam supply valve RCIC Steam Supply From main steam line "B" to RCIC turbine steam supply valve ! Main Steam Drain Lines From main steam lines inside drywell to inboard containment isolation valve; from main steam lines outside drywell to outboard i containment isolation valve and drain line isolation valves RPV Head Vent Line From reactor vessel head nozzle to main steam j line "C" Standby Liquid Control From reactor vessel nozzle to first upstream check valve 12-1481 '2 - 5

                                                                    - . - - - . , - - -     . . . ~ . . - - -

l INITIATING HIGH ENERGY PIPING SYSTEMS (CONTINUED) FLUID SYSTEM EXTENT OF HIGH ENERGY PIPING RHR Shutdown Cooling Suction From reactor recirculation loop to inboard containment isolation valve RHR Shutdown Cooling Return From reactor recirculation loop to first j upstream check valve LPCI Injection From reactor vessel nozzle to first upstream check valve Core Spray Injection From reactor vessel nozzle to first upstream

                 .-                                          check valve

! Control Rod Drive Hydraulic From drive water pump to master control station to hydraulic control units I Auxiliary Steam From auxiliary boiler to various steam consum-ing components High Pressure Drains From final feedwater heater to associated drain valve in each i edwater heater string Extraction Steam From main steam line "B" . to feedwater pump turbines; from crossaround steam lines to feedwater heaters and feedwater pump turbines; from moisture separators to feedwater heaters , and condenser inlet valves; from high and low i pressure turbines to feedwater heaters Air Removal From main steam line "C" to steam seal evaporator

    .       Turbine EHC                                      From electro-hydraulic control power unit to turbine stop valves (MSV's), ccabined inter-cept valves (CIV's) and bypass control valves l

l l l 12-1481 2-6

2.4 ZONE DETERMINATION l The Turbine and Reactor Enclosures for Limerick Unit I were. separated into definable sections referred to as zones. The zones were defined in terms of area, elevation, and grid location. The area designation corresponds to the scheme shown in Figure 1 of Appendix B. The major plant elevations, as shown in the remaining figures of Appendix B, were used to define the elevation. The grid location was used to further define the zone with a grid designation which approximates the center of the location of concern. A zone need not exist entirely ' within one area or one elevation. The zones were initially constructed along existing boundaries such as concrete walls and floors using the appropriate Architectural Drawings (Reference 5) as guides. Zones were initially maintained as large as

                            ..       possible for conservatism in applying the " sacrificial" approach in the analysis. The " sacrificial" approach assumes that any HELB within the defined zone would impact all control system components in the zone. Using this approach, the effects of pipe whip, jet impingement and adverse environment are enveloped. Further divisions of zones were performed where a pipe break was judged to affect the components in only a confined portion of an " architecturally" defined zone. The bases for these judgements are detailed in Section 2.5.2. One example i                                     is the main turbine condenser bay areas. A high energy line break postulated to occur on the south side of the condenser area at Eleva-l                                     tion 217 (see Figure 3 of Appendix B) is assumed not to affect control systems components on the north or south side of the condensers at any 4

' major elevation other than that at which the pipe break occurs. The bays allow for the adverse environment associated with the break to spread throughout the condenser bay up to the turbine main floor, which is also a large, open zone, minimizing the environmental effects on other areas within the condenser bay. Therefore, even though no air / steam / water boundary exists in the condenser bays between Eleva-tion 217 and 'other elevations, the zone is defined in- terms of the condenser bays at Elevation 217, for which the " sacrificial" approach l is used. The Analysis Summary in Appendix A reflects this approach. For the Reactor Enclosure, the zones of influence defined in the FSAR 4 Chapter 3.6 were used. The figures in Appendix B detail the final i zones used for the study. 2.5 PIPE BREAK LOCATION AND EFFECTS 2.5.1 PIPE BREAK LOCATION t The high energy pipes defined by the table in Section 2.3.1 of this report are assumed to break at all locations where control systems components of concern (defined in Section 2.2) are physically located in the vicinity of the high energy piping, unless piping runs subject i to high stress have been specifically identified and analyzed as a result of the studies in FSAR 3.6.1. Piping evaluated via-previous HELB studies (see FSAR 3.6) are considered to break as defined. in those studies. Only one pipe break is postulated to occur at any one time and only during normal plant conditions. Normal plant conditions 12-1481 2-7

o . are defined as the plant operating conditions during reactor startup, operation at power or reactor cooldown .to cold shutdown excluding upset, emergency, faulted, or testing conditions (see Section 2.1, Item 5). As part of the detailed analysis described in Appendix A, the worst case combination of a specific HELB and consequential control systems failures is examined for the reactor in the limiting I condition (i.e., "Startup" or "Run" mode) for that postulated event. 2.5.2 PIPE BREAK EFFECTS Pipe breaks and consequential control systems failures are evaluated considering the effects of pipe whip, jet impingement and adverse environment on the control systems components. The effects associated , with any adverse environment (increasing humidity, temperature, pressure, radiation) are enveloped by employing the " sacrificial" approach. The " sacrificial" approach assumes that any HELB within the defined zone (area / elevation / grid location) would adversely impact all control systems components in the zone. Using this approach, environ-mental effects are enveloped in the detailed analysis presented in Appendix A. 2.5.2.1 PIPE WHIP CONSIDERATIONS

The criteria used for evaluating the effects of pipe whip are consis-

, tent with the analysis performed in Reference 4. Movement of a circumferential1y broken pipe is assumed to occur in the direction of the jet reaction while the pipe hinges at the nearest rigid support, 4 anchor, or penetration, producing an arc of motion. The pipe is allowed to move in an arc with a radius from the break to the hinge point and motion is assumed to be limited by pipes of equal or greater diameter or reinforced concrete walls, floors, or columns. The whipping pipe is assumed capable of incapacitating any control systems component within the are of motion. The " sacrificial" approach detailed in Section 2.4 envelopes these pipe whip considerations. 2.5.2.2 JET IMPINGEMENT CONSIDERATIONS Jet impingement is considered for both circumferential and longitu-dinal breaks. The criteria used for evaluating the effects of jet impinsement are consistent with those listed in Reference 4. The basic approach assumed is that the jet from a postulated break is c sufficient to fail all impacted components within the jet cone of ! influence for a distance of 25 feet, except in those areas where major - ! structures provide natural barriers. The " sacrificial" approach used , in this analysis (see Section 2.4) envelopes these jet impingement

considerations.

i 2.6 PLANT WALKDOWN 2.6.1 WALKDOWN PREPARATION i The appropriate Architectural, Piping and Mechanical, and Instrument Location Drawings (Reference 5) were gathered in preparation for a plant walkdown. The drawings were used to define preliminary zones l 12-1481 2-8 i

                          , ,   ,--   . , , - . . -   - , . - , , - , , - . - - - - - ~ . - - - - - . - -

j where control systems components of concern (Sections 2.1 and 2.2) and high energy lines (Section 2.3) coincide. 2.6.2 WALKDOWN EFFORT The plant walkdown was performed to accurately define appropriate zones, verify the location of control systems components, and assess the proximity of the components and associated taps and tubing to high 4 energy lines. i Using the pipe break criteria established in Section 2.5.2, control systems components affected by a HELB were determined for each high j energy line in each zone. The " sacrificial" approach envelopes the effects of pipe whip, jet impingement and adverse environments on instruments which exist within the same zones as high energy lines.

,                .-             During the walkdown, the pipe whip and jet impingement criteria vere conservatively applied in judging which instrument taps and tubing j

could be adversely affected. In some cases, no high energy lines existed in the vicinity of controlling components. A number of zones and many components were eliminated from the detailed analysis as a result of the plant walkdown. All areas of the Radwaste and Diesel Generator Enclosures were elim-insted from the detailed analysis since no high energy lines are routed through these enclosures. The Auxiliary Boiler Enclosure was eliminated since only Auxiliary Steam System components exist within i the enclosure. Specific zones of the Reactor and Turbine Enclosures eliminated are noted in the analysis presented in Appendix A. 2.7 ZONE ANALYSIS I I J The detailed analysis was performed ou a zone by zone basis. The

following description is representative of the analysis performed for l each zone. Appendix A, which presents the summary of the analysis for

{ each zone, follows this format. +

    .                           I.         High Energy Systems 1

i A list was made which identified all the high energy piping in i the zone. Each high energy line was reviewed to determine the l effects of a piping failure upon its own system. This was done ! for each high energy line independently, since only a single pipe break is postulated as the initiating event. The effect of the break itself on reactor parameters was examined and the bounding FSAR Chapter 15 event identified, where appropriate. i ! II. Control Systems $ A list was made of all control systems components within the i sone. The failure mode (s) of each component and the effect(s) of { its failure on all controlled components were reviewed. Con-i trolled components are assumed to operate in the worst possible ] node as a result of the failure. 12-1481 2-9 .

p III. Combined Effects The postulated piping failure for each high energy line in the zone was examined in combination with the resulting, worst case failures of control systems components in the zone to detemine if any combination of possible failures could exacerbate the postulated HELB. The " sacrificial" approach detailed in Sec-tion 2.4 was used, and the worst case combined HELB and possible consequential control systems failures were defined. The conse-quences of these events were then compared to the accident and transient analyses presented in the FSAR, Chapter 15, which include discussions of a single additional active component failure, to ensure they are less severe than the existing analyses. I 4 1 i l l l \ 12-1481 2 - 10

I

3.0 CONCLUSION

S AND RECOMMENDATIONS The Analysis Summary of Appendix A presents a summary of the results of the analysis performed for those zones of the Turbine Enclosure and Reactor Enclosure which required the detailed analysis described in Section 2.7. The " sacrificial" approach, as outlined in Section 2.4, has been applied, and conservative assumptions have been applied to

all analyses of system failures. No credit has been taken for opera-
tor action in any event beyond those already assumed in the existing i FSAR Chapter 15 analyses.

The worst-case combined effects of the postulated ELB and consequen-tial control systems failures have been examined. In many cases, the i postulated ELB is not exacerbated by any combination of control systems failures in the zone. The " Combined Effects" portion of the analysis for each zone in Appendix A describes the conditions result-ing from each ELB and the associated control systems failures in each zone. The " Combined Effects" sections also define the appropriate

 .                         FSAR Chapter 15 events, which discuss the effects of a single addi-l                           tional active component failure, which exhibit the same or more severe i

effects than the postulated events (i.e., " bounding" events). i The worst postulated combination of events presented in the analysis ' of Appendix A occurs from a pipe break in the Turbine Enclosure, Areas 1,2/ Elevation 217/ Grid Q15, the moisture separator drain tank area. A ELB within this zone may cause a partial loss of feedwater heating and an eventual turbine trip, if the appropriate instrumenta-tion and controls are disabled leading to improper valve positioning. j Using the " sacrificial" approach, which assumes that all control systems components in the zone could fail in the _ worst possible i combined manner, the loss of feedwater heating which could occur is

 ;                         less than 30*F. This assumes the break occurs in the most critical location 'of an Extraction Eteam line and the resulting pipe whip or jet impingement causes failure in the worst case combinations of instruments on all six moisture separators. Data compiled during the
       .                   plant walkdown effort indicates that such an event is unlikely. Even a circumferential break in the most critical line/ location discussed above could impact, via pipe whip and/or jet impingement., instruments
,                          on' only three moisture separators.           This is due to the physical j                           distance between the two sets of three moisture separators.

i For this event, the reduction in feedwater inlet temperature causes a l gradual rise in reactor power. Depending on the specific timing involved, the turbine trip may occur at power level elevated from the

;                          initial operating value.      Investigation has shown that, should this unlikely worst case combined sequence occur, the reactor may experi-i ence a change in the critical power ratio greater than that shown in the Unacceptable Results for Incidents of Moderate Frequency - Antici-l                           pated Operational Transients of FSAR Chapter 15, but only for a short time. However, the effects of this accident event, even considering i

an' additional single active component failure, pose no threat to the Unacceptable Results. for Limiting- Faults - Design Basis (Postulated) l Accidents presented in the FSAR, Chapter 15. l l l l 12-1545 3-1

          -                                                                                       1
        .                                                                                         l All other " Combined Events" are bounded by the accident and transient events analyzed in FSAR Chapter 15, as noted in Appendix A. It is concluded that a postulated high energy line break and resulting control systems failure event poses no threat to the transient and accident limits set forth in the FSAR Chapter 15, and does not result in any significant risk to the health and safety of the public. No further accident analysis or design modifications are recommended.

e ( 4 I i 12-1545 3-2

4.0 RE N NCES

1. Bechtel Power Corporation, " Mechanical and Electrical Equipment List for Limerick Generating Station Units 1 and 2", Revision 44, November 4, 1983.

2. Bechtel Power Corporation, " Instrument Index List - EBOP Data Base", Revision 50, November 14, 1983.

3. Nuclear Regulatory Commission, " Standard Review Plan 3.6.2 -

Determination of Rupture Locations and Dynamic Effects Associated with the Postulated Rupture of Piping", Revision 1, July 1981.

4. Bechtel Power Corporation, "High Energy Pipe Break Report", by A.

V. Benamou and J. Berry (no date).

5. Bechtel Power Corporation, " Architectural Drawings - Air / Steam /

Water Boundaries": Drawing Revision A-305 10 A-306 9 A-307 7 A-308 7 A-309 7 A-310 6 A-311 5 I l 12-1546 4-1

         ,                                                                                                                      1 i

1 (Reference 5, Continued) Bechtel Power Corporation, " Instrument Location Drawings": Drawing Revision Drawing Revision M-150 52 M-197 18 M-151 34 M-198 8 M-152 27 M-200 12 M-153 24 M-201 16 M-154 14 M-202 27 , M-155 14 M-203 9 M-157 71 M-485 44 M-158 80 M-159 68

                .. M-160           40 M-161           27 M-162           37 M-163           71 M-164           53 M-165           52 M-167           44

, M-168 32 M-169 17 M-170 21 M-172 15 M-173 53 M-174 22 M-175 24 M-176 16 M-177 23 M-178 12 M-179 14 M-180 28 M-181 16 M-182 11

     ,               M-183           44 M-184           65 M-185           44 M-186           35 M-187           39 M-188           31 M-189           24 M-190           13 H-191             7 M-193           22 M-195           56 l

M-196 28 - I I l t 12-1546 4-2 l _ _ . _ _ _ _ _ . . . . _ _ _ _ , _ _ _ . . _ _ - - _ _ _ _ _ _ _ . _ . _ _ .

1 (Reference 5, continued) Bechtel Power Corporation, " Instrument Location Drawings": Drawing Revision Drawing Revision M-675 13 M-726 17 M-676 11 M-727 14 M-677 8 M-728 3 M-678 7 M-729 4 M-679 14 M-731 5 M-680 8 M-732 8 M-681 14 M-733 3 M-682 6 M-734 5 M-683 6 M-749 6 M-685 5 M-750 4 M-686 9 M-751 8 H-687 6 M-753 7 M-688 4 H-754 9 H-689 10 M-766 0 M-690 5 M-843 0 M-691 7 M-844 2 M-693 7 M-848 4 M-694 2 M-850 2 M-695 12 M-696 13 M-697 7 M-699 9 M-700 2 M-704 14 (Sh. 1) 4 (Sh. 2) M-705 12 M-706 12 M-707 17 M-708 16 M-709 16 M-710 7 M-711 8 M-712 12 M-713 13 M-714 19 M-715 18 M-716 3 M-717 13 M-718 16 +

M-719 18 i M-720 17 l M-721 12 .

M-722 6 M-723 15 M-724 12 M-725 11 l 12-1546 4-3

 - . _. _ _ . _       _    m .. _ _     _ _ . _ _ _ . _ _ - _ . _ _ _ . - _ _ . _ _ _ _ _ . _ _ _ _ _ . _ _ . _ _ _ - . _ _ . _ . . _

6. General Electric - LSTG, "High- Pressure Hydraulic Fluid Piping" Diagrams: ,

Drawing Revision 824E519 3 ! 838E889 2 [ i i ( i i i I I

l 12-1546 4-4 1

l l l l l 1 i APPENDIX A ANALYSIS

SUMMARY

l l l l l l l l l 12-1482 A-1

I Note that the format followed throughout this Appendix is presented and described in Section 2.7. TURBINE ENCLOSURE 1

,                The Turbine Enclosure was divided into the zones listed below, These zones are represented in Figures 2 through 7 of Appendix B. Also noted below are the zones eliminated from the detailed analysis for at least one of the following two reasons:

1. No high energy lines are routed through this zone.

2. All control systems components which reside within this zone have been i eliminated per the criteria detailed in Sections 2.1 and 2.2 of this

                    ,, report. Therefore, no applicable control systems components reside within
]                       this zone.

i Zone Eliminated (?) Reason i Area 2/ Elevations 189,200/ Grid Q15 No Areas 2,3/ Elevations 189,200,217/ Grid R20 No Areas 6,7,2/ Elevation 200/ Grid M12 No i Area 8/ Elevation 200/ Grid M21 Yes 2 ) Area 1/ Elevation 217/ Grid Q6 No i l Areas 1,2/ Elevation 217/ Grid Q15 No Areas 2,3/ Elevation 217/ Grid Q20 Yes 2 Areas 2,3/ Elevation 217/ Grid P20 Yes 2 $ Areas 2,3/ Elevation 217/ Grid P22 Yes

     ,                                                                                                                 1 Areas 6,7/ Elevation 217/ Grid M15                                    No i

i Area 8/ Elevation 217/ Grid H21 Yes 1 Area 1/ Elevation 239/ Grid Q7 Yes 1 Areas 1,2/ Elevation 239/ Grid P14 No Areas 2,3/ Elevation 239/ Grid P20 Yes 1 j Area 6/ Elevation 239/ Grid M7 No

,! Areas 6,7/ Elevation 239/ Grid M12 Yes 2 Area 7/ Elevation 239/ Grid M16 Yes 2 i l t 12-1482 A-2

Zone Eliminated (?) Reason

       . Areas 6,7/ Elevation 239/ Grid J14                                              Yes                   1 Area 8/ Elevation 239/ Grid K22                                                 Yes                   1 Area 1/ Elevation 269/ Grid Q(n)10                                              Yes                  2 Areas 1,2,3/ Elevation 269/ Grid Q15                                            No Area 6/ Elevation 269/ Grid N9                                                  No Area 7/ Elevation 269/ Grid N14                                                 Yes                  2 Area 7/ Elevation 269/ Grid N16                                                 No Areas 6,7/ Elevation 269/ Grid M12                                              No i

Area 8/ Elevation 269/ Grid M22 Yes 1

Areas 6,7/ Elevation 302/ Grid M12 Yes 1 Area 7/ Elevation 302/ Grid K14 Yes 1 Area 8/ Elevation 304/ Grid M22 Yes 1 Area 8/ Elevation 321/ Grid K(f)23 Yes 1 Area 8/ Elevation 332/ Grid M23 Yes 1 Area 8/ Elevation 350/ Grid K(f)23 Yes 1 i

1 I 12-1482 A-3 i

6 Area 2/ Elevations 189,200/ Grid Q15 I. High Energy Systems A. Extraction Steam

1. 10" GBD-103 !

a. Function: Six lines designated GBD-103 carry inventory I from the six moisture separator drain tanks to feedwater l heaters 14AE104, 14BE104, and 14CE104.

b. Effect of Break: A break in any of these six lines results in a loss of inventory through one of the moisture separa-

                       ..                                    tors and a loss of some (<100*F) feedwater heating. The                                      ,

effects of this break are bounded by the Loss of Feedwater ' Heating event (FSAR 15.1.1).

2. 6" GBD-131; 6" GBD-133

a. Function: Six lines tap off from the six 10" GBD-103 condensate lines discussed above. These lines carry inventory from the moisture separator drain tanks to the high pressure or low pressure condensers. These lines are high energy up to normally closed, fail open valves up-stream of the condensers.

b. Effect of Break: A break in any of these six lines results in a loss of inventory through one of the moisture separa-tors and a loss of some (<100*F) feedwater heating. The effects of this break are bounded by the Loss of Feedwater i Heating event (FSAR 15.1.1).

B. Condensate

, 1. 30" GBD-116

a. Function: Condensate supply line from the condensate

!                                                            filter demineralizers to the inlet nozzle of the feedwater drain coolers IAE107, IBE107, and ICE 107.

b. Effect of Break: Line break results in a feedwater line break event. The effects of this break are bounded by the Feedwater Line Break Outside Primary Containment event
(FSAR 15.6.6).: 2. 20" GBD-117 .; a. Function: Three lines designated GBD-117 carry condensate from the three drain coolers to the first feedwater heater
in each string of heaters.

1 12-1482 A-4

t . 4 4

b. Effect of Break: Line break results in a feedwater line break event. The effects of this Dreak are bounded by the )

1 Feedwater Line Break Outside Primary Containment event i (FSAR 15.6.6). C. Auxiliary Steam

1. 8" GBD-176

s. Function: Provides steam for heating the LP, IP, and HP condenser shells on the low pressure turbines "C", "B", and

,! "A", respectively.

!                                                                b.          Effect of Break:                                        Loss of the above discussed heating capabilities.

1 II ." Control Systems ;

A. Extraction Steam

1. ZS-02-112C,113C i

a. Function: Control position of level control valves LV-C 02-112C and 02-113C which are normally open, fail closed 1

valves in lines leading from two moisture separator drain tanks to feedwater heater 14CE104.

!                                                                b.          Failure Effects: These position switches could cause LV-Cs 112C and 113C (normally open) to close. Effect of closure is a loss of some (<100*F) feedwater heating.

III. Combined Effects

!                                                  A.      An Extraction Steam line break would result in a gradual loss of 1

inventory through the Main Steam system, and a reduction in feedwater ! heating. Closure of the valves in the lines sh bing extraction steam to the 14CE104 feedwater heater could result in an additional i loss in feedwater heating capability. The total loss of feedwater

!                                                          heating is less than 100*F, and the effects of this event are bounded

! by the Loss of Feedwater Heating event analyzed in FSAR 15.1.1. An additional single active failure in a mitigating system also results in a bounded event, as discussed in FSAR 15.1.1. B. A Condensate l'ine break in this zone is bpunded by the Feedwater Line Break Outside Primary Containment event analyzed in FSAR 15.6.6. The l possible failures of control systems components in this zone will not exacerbate this event. An additional single active failure in a mitigating system also results in a

bounded event, as discussed in FSAR 15.6.6.

C. The Auxiliary Steam system functions are required during reactor startup and pre-startup operations. Such a break could abort a startup, but would not have an adverse impact on the reactor para-meters. If the line break adversely affects the control system , 12-1482 A-5

   .        ..n , , , , . -n             ---n
                                           .          -s--   ,w-    --,e---    =w--~~*wn-r~'^'~'~*' * * * ' * " ' " ' " ' ~ ~ ' ~ ~ * ~ " * ' ' " ~          ~ ~ ' ' ~ ~ ~ ~ ~ ' " ~

components in the zone, a partial loss of feedwater heating (<100*F) could result. The effects of this event are bounded by the Loss of { Feedwater Heating event analyzed in FSAR 15.1.1. An additional

single active failure in a mitigating system also results in bounded event, as discussed in FSAR 15.1.1.

i 1 k 4 i 12-1482 A-6

                     +-----,--.-n+.              _,ey       -    .         - ,.,,,,,-,,a.,+--,nn.
                                                                                                        +--_,-,v.--,.           --m.. y --ew- _ - - - - . , . , ,

Areas 2.3/ Elevations 189.200.217/ Grid R20

1. High Energy Systems A. Auxiliary Steam

1. 12" GBD-176; 4" GBD-135

a. Function: Provide steam for heating the LP, IP, and HP condenser shells on the low pressure turbines "C", "B", and "A", respectively.

b. Effect of Break Loss of the above discussed heating capabilities.

                 " 3. Condensate

1. 18" GBD-109

a. Function: Three 18" lines designated GBD-109 carry conden-sate from the outlet of the condensate pumps to common header 30" GBD-109 which carries condensate to the steam jet air ejector condensers,

b. Effect of Break A break in any of the three GBD-109 lines results in a feedwater line break event. The effects of such a break are bounded by the Feedwater Line Break Outside Primary Containment event (FSAR 15.6.6).

II. Control Systems A. Condensate

1. NY-05-110A,B,C; NC-05-110A-1,A-2,3-1,3-2,C-1,C-2

     ,                       s. Function:     Control   normally-clos'ed, fail-open valves (MV-C 05-110A,B,C)    on the    three lines designated 10" GSD-108 from main steam to the condenser hotwell sparsers on LP turbines "A", "B", and "C". However, NV 01-109 is a normally closed valve upstream (i.e., closer to the main steam tapoff) than the controlled valves such that there is no steam downstream of NV 01-109.

b. Failure Effects: Instrument failure could cause the NV-C 05-110 valves to open during a time when they are normally closed. The opening of these valves has no effect due to NV 01-109 being closed. NV 01-109 is unaffacted.

! 2. PSL-05-107,108 i a. Function: Nonitor pressure on condensate pump "A" dis- , charge and control valves LV-C 05-104 (fail-closed) in the i i 12-1482 A-7

1 condensate reject line and TV-C 05-103 (fail-open) in the , condensate recirculation line.

b. Failure Effects: Failure of both pressure switches would c generally result in closure of LV-C 05-104, the reject l line, and opening of FV-C 05-103, the recire line. This

would result in a slight reduction in feedwater flow. If failure of the instruments resulted in opening both the condensate recire and reject lines, a larger reduction in feedwater flow would be realized. III. Combined Effects i A. The Auxiliary Steam system functions are required during reactor startup and pre-startup operations. Such a break could abort a

                 ,.           startup, but would not adversely impact the reactor parameters. A break in this system in this none which affects the control systen components in the sone could result in a loss of some feedwater flow.

The effects of this partial loss of feedwater flow are bounded by the Loss of Feedwater Flow event analysed in FSAR 15.2.7. An additional i single active failure in a nitigating system also results in a ! bounded event, as discussed in FSAR 15.2.7. ( B. A break in the condensate system piping in this some results in a feedwater line break event. The effects of this event are bounded by the Feedwater Line Break outside Primary containment event analyzed in FSAR 15.6.6. The event is not exacerbated by the failure of any control systes components within this zone. An additional single active failure in a sitigating system also results in a bounded event, as discussed in FSAR 15.6.6. " l f I h - l . l i 12-1482 A-8

     -                .  . . _ _- _ -_ - - - . - - . _ - . - -                                                                     - - - _- . _- _- - _. -.._ - .                      -. - - _ .             ~

i. Areas 6.7.2/ Elevation 200/ Grid M12 l l I. High Energy Systems

! A. Condensate

1. 30" GBD-111; 30" GBD-116 t

j a. Function: Condensate supply lines from the steam packing enhauster through the condensate filter domineralizers to i the feedwater drain coolers. i i l b. Effect of Break: A break in this line results in a loss of condensate supply to the Feedwater system. This break is i ! bounded by the Feedwater Line Break Outside Primary Con-tainment event (FSAR 15.6.6).

2. 12" GBD-115 l a. Function: Condensate reject line.

i l b. Effect of Break: A break in this line results in a loss of some condensate supply to the Feedwater system. This break is bounded by the Feedwater Line Break Outside Primary Containment event (FSAR 15.6.6). I { B. Auxiliary Steam 1 l 1. 10" JBD-7 } ! a. Function: Supply steam to the condensate storage tank j (CST) and refueling water storage tank heaters. 1 !

b. Effect of Break Loss of heating capability for these tanks. .

l 2. 4" GBD-136 j a. Function: Test steam supply for the RCIC and DCI i turbines. j b. Effect of Break Loss of test steam supply to RCIC and l' DCI turbines. Line is blind flanged during operations i other than testing. 1 II. Control Systems l ! A. Estraction Steam i ! 1. NY-02-115 i l l a. Function: Controls one normally closed, fail open salve in l l a 2" line from the D turbine to the D condenser. l l l 12-1482 A-9

                                                                                                                                         ,,n-~-,.mr.          v  ..--,,n- ,,,,-.-v.--,      ,.e   ----, -,-.-

v-------r, .,,,e,--,- ,,,..rn,- _ .n- . , - - -, -.---,-..,,-,nnr,-,----_.

i i , b. Failure Effects: A slight loss of feedwater heating l (<100*F) would result if the valve were opened during

normal operation.

B. Condensate

1. LT-05-101A,B 4

a. Function: Control throttle valves which are fail-closed valves in the condensate lines from the condensate storage

! tank (CST) to the HP condenser shell on LP turbine "A." ! They also control normally-closed, fail-closed valves in j the condensate reject line. l

b. Failure Effects: The worst case failure of these compon-i -

ents would be to open the above valves. Opening the first ! set would send CST water to the condenser, which may affect condenser vacuum in the long term (>15 minutes). Opening

the second set of valves results in a possible reduction of
feedwater flow.

. 2. LC-05-116A,B i ,

s. Function: Control valves in the condensate lines from the condensate drain tank to the HP condenser shell on LP turbine "A."

b. Failure Effects: The worst case failure of these compon-i ents would be to close the drain tank valves, which would cause the drain tank level to rise. This will have no effect on the reactor parameters.

} C. Feedwater i ) 1. PSL-06-102A,B,C

)                                                                                    '

1

       .                        a. Function:    Provide the low net pump suction head (NPSH) j                                     trip signal to the reactor feedwater pump turbines (RFPT).

b. Failure Effects: Failure to provide the trip signal may ,

i result in pump cavitation and loss of feedwater flow. i Failure of the components such that a trip signal is ! generated would result in a loss of feedwater flow. I i 2. IT-06-101A,B,C 1 l a. Function: Control the condensate recirc flow control valve l to the LP condenser shall 6n the LP turbine "C." } b. Failure Effects: The worst case failure of these compon-

ents would be to open the above valve, resulting in a l possible reduction of feedwater flow.

I I 12-1482 A - 10 I

                              -_                                 _ _ - .        .     --     -.                                       .              ~ . . - _

3 l l

3. XC-06-106A,B,C

a. Function: Control feedwater flow from the reactor feed-water pumps (RFP) to the HP, IP, and LP condenser shells, i.e., the minimum flow recirculation line.

b. ' Failure Effects: The worst case failure of these compon-ents would be to open the valve, resulting in a possible reduction in feedwater flow.

I D. Service Water .

1. FSL-10 160

a. Function: Provides control of the low pressure air blower

                          .-                                              (10K105) which is the air supply to the condensate filter desineralizers and the Air Removal and Sealing Steam system.

b. Failure Effects: No adverse consequences would result from this component failure. There are normally-closed valves
downstream of the blower in each of the subject lines which
are not affected.

l E. Compressed Air

1. PC-15-150 l a. Function: Provides control of the low pressure air blower (10K105) which is the air supply to the condensate filter demineralizers and the Air Removal and Sealing Steam system.

i b. Failure Effects: No adverse consequences would result from i this component failure. There are normally-closed valves j downstream of the blower in each of the subject lines which

. are not affected.

i l F. CRD Hydraulic . 1. PSL-46-N001A,B I a. Function: Control the CRD drive water pump flow from the l condensate reject line to the HCUs.

b. Failure Effects: Only long term operation of the HCUs i would be impaired. No impact on scram or the reactor parameters would result.

III. Combined Effects A. A break in any of the Condensate System lines in this zone is bounded i by the Feedwater Line Break Outside Primary Containment event i ! 12-1482 A - 11

l analyzed in FSAR 15.6.6. The failure of any control systems compon- , ents in- this zone does not exacerbate this event. An additional single active failure in a mitigating system also results in a bounded event, as discussed in FSAR 15.6.6. B. The Auxiliary Steam system functions are required during reactor startup and pre-startup operations. Such a break could abort a startup, but would not have an adverse impact on the reactor para-i meters. The worst case effect of the HELB and its effect on control systems components is bounded by the Loss of Feedwater Flow event analyzed in FSAR 15.2.7. An additional single active failure in a mitigating system also results in a bounded event, as discussed in FSAR 15.2.7. 5 i e i l l i l I l 12-1482 A . }g

 ,                                                                                        Area 1/ Elevation 217/ Grid Q6 l

I. High Energy Systeies !

"                                                                                                                                                                                                                                                             I A.                  Turbine Electro-Hydraulic Control (EHC)                                                                                                                                                 '

1. 14"/2" FAS, Fluid Actuator Supply i

a. Function: High pressure fluid lines serve to maintain the main turbine stop valves (MSV) and combined intermediate valves (CIV) open, and control the bypass control valves.

i ! b. Effect of Break: Loss of EHC system pressure resulting in reactor scraa. Reactor scram is RPS (Reactor Protection

                                        ..                                        System) scram on loss of EHC pressure and/or closure of the MSV's.

i II. Control Systems i A. Service Water 4

1. TE-10-106A,B; TIC-10-106A,B

a. Function: Control valves TC-V 10-106A,B (normally open, l fail-open) which supply service water to EHC hydraulic '

] fluid coolers.

b. Failure Effects: Failure of these instruments such that the controlled valves would close results in a loss of EHC fluid cooling.

III. Combined Effects I A break in any portion of the Turbine EHC Fluid Actuator Supply line will

result in a loss of EHC system pressure.. This loss of pressure will t

) , actuate RPS scram functions on loss of EHC pressure and/or PSV closure. l The effects of this event are bounded by the Turbine Trip Without Bypass ' i event analyzed in FSAR 15.2.3. The failure of any control system compon-ents in the zone which could possibly be adversely affected will not exacerbate this event. An additional single active failure in a sitigat-t t ing system also results in a bounded event, as discussed in FSAR 15.2.3. l i 12-1482 ,A - 13 1 __ _., ~-_ ._, _ _ _ _ _ _ . . _ , , . . _ . _ . . ~ . . _ . _ . . . . . . _ . . _ . . . . _ , . _ . - . , . _ _ . . . _ , _ _ _ . _ , _ _ _ . , . . _ _ , . _ _ _ , . . _ . _ . _ .

      -                                                                                                                                                       i 4

Areas 1.2/ Elevation 217/ Grid Q15 4 1 I. High Energy Systees A. Extraction Steam i

1. 10" GAD-10s

a. Function: Low pressure steam supply for the three reactor feedwater pump turbines from crossaround steam.

i i b. Effect of Break: Loss of inventory through the break and a loss of low pressure sessa supply to the feed pump tur- i

bines. The high pressure backup supply is available. I 1 2. 10" GJD-101 i a. Function: Two lines dest;;nated GJD-101 supply feedwater i beater 14CE104 with stese from two moisture separators.; b. Effects of Brca' s: Loss of inventory through one moisture j separator and a loss of some (<100'F) feedwater heating. (

;                                                                  The effects of this break are bounded by the Loss of Feed-                                 l

. water Nesting event (FSt.R 15.1.1). .: 3. 10"/8" GBD-103 i

i

a. Function: Six lines designated GBD-103 carry inventory ,

from the. six moisture separator drain tanks to feedwater ! heaters 14AE164, 143E104, and 14CE104. ; { i !. b. -Effect of Break: A break in any of these six lines results j in a loss of tuventory through one of the moisture separa- , j tors and a loss of some (<100*F) feedwater heating. The - 1 effects of this break are bounded by the Loss of Feedwater j ,

                                                                  - Meating event (FSAR 1$.1.1). '                                                            i 1

4. 6" G3D-331; w" G*D-133

]

a. Functioni six lines tap off from the sin 10" GBD-103 l l condecsate lines dircussed above. These lines carry '

i inventory from the soisture separator drain tanks to the i high Fressure or low pressure condensers. These lines are } bish energy up to normally-closed, fail-open valves up-stresa of the condensers.

b. Effect of Bre(si A break in any of these six lines results i in a loss of inventory through one of the moisture separa-

!                                                                   tors and a loss of some (<100*F) feedwater heating. The i                                                                   effects of this bresk are bounded by the Less of Feedwater l                                                                   Beating event (FAAR 1S.1.1).

12-1482 A - 14 c

        -        - -. ,        .--,,-.,~..-,...n-.,m,,                 ~ - - - - , -_

f 9 i

B. Main Steam

! 1. 6"/4" ESD-113 ? I a. Function: High pressure steam supply for the three reactor j feedwater pump turbines. This is a backup steam supply. 4 j b. Effects cf Break Loss of inventory through the main steam i system and a loss of the backup high pressure steam to the i feed pump turbines. j C. Feedwater i

;                         1.      20" GBD-116 i

f .- a. Function: Condensate supply line from the condensate i filter domineralizers to the inlet nozzle of the feedwater

;                                         drain coolers 1AE107, 18E107, and 3CE107.

i l b. Effect of Break Line break results in a feedwater line j break event. The effects of this break are bounded by the

Feedwater Line Break outside Primary Containment event (FSAR 15.6.6).
2. 20" GBD-117 i a. Function: Three lines designated GBD-117 carry feedwater

 !                                        from the three drain coolers to the first feedwater heater j                                          in each string of heaters.

b. Effect of Break Line break results in a feedwater line break event. The effects of this break are bounded by the

{ s Feedwater Line Break outside Primary Containment event { (FSAR 15.6.6). 1 D. Auxiliary Steam . i 1. 6" GSD-146 }

a. Function: Supply steam to various steam consuming compon-eats used during startup operations.

t b. Effect of Break: A break in this line may abort a startup, but will not adversely affect the reactor parameters. E. Turbine Electro-Nydraulic Control (INC) i j 1. 14"/2" FAR, Fluid Actuator Supply I a. Function: Mish pressure fluid lines serve to esistain the l mata turbine stop valves (NSV) and combined intermediate j valves (CIV) opea, and control the bypass centrol valves. l 12-1442 A - 15

b. Effect of Break: Loss of EHC system pressure resulting in reactor scram. Reaccor scram is RPS (Reactor Protection Systec2) scram on loss of EHC pressure and/or closure of the

. MSV's'. II. Control Systems A- Main Steam l l

1. LT-01-101A-F; LT-01-103A-F

                        -                                                                                            l l

a. Function: Provide level control in the six (A through F) moisture separator drain tanks by opening / closing valves in the exhaust lines to feedwater heaters 14AE104, 14BE104, and 14CE104, and the HP, IP, and LP condensers of low

                  ..                  pressure turbines            "A", "B", and "C". The co. trolled valves in the lines to the condensers (LV-C 01-103A-F) are nor-mally closed and fail open. The controlled valves in the lines           to     the    feedwater heaters       (LV-C 01-112A,B,C; LV-C 01-113A,B,C) are normally open and fail closed.

b. Failure Effects: These level transmitters could fail in such a manner that the exhaust lines to the condensers open ,

and the lines to the feedwater heaters close. If the instruments fail in such a manner that both exhaust paths from at least one moisture separator are closed, a partial loss of feedwater heating (<100*F) would occur, and a turbine trip could result from high level in the moisture separator.

2. LSHH-01-115A-F; LSHH-01-116A-F; LSHH-01-117A-F

a. Function: Three switches per . moisture separator provide a turbine trip signal when two out of three level switches register high-high level in -any of the six moisture separators. ,

b. Failure Effects: Failure of any two level switches on one moisture separator may result in a turbine trip. These switches could also fail in a manner that would incapaci-tate a turbine trip.

B. Condensate

1. Instrument process tubing for all *of the following components:

HY-05-110A,B,C; XC-05-110A-1,A-2,B-1,B-2,C-1,C-2 l a. Function: Control normally-closed, fail-open valves (HV 05-110A,B,C) on three lines designated 10" GBD-108 from main' steam to the condenser hotwell spargers on LP turbines "A", "B", and "C". However, HV 01-109 is a normally-closed valve upstream (i.e., closer to the main steam tapoff) than the controlled valves such that there is no steam down-stream of HV 01-109. 12-1482 A - 16

b. Failure Effects: Severance of the instrument tubing can result in opening of one or more of the HV-C 05-110 valves during the time they are normally closed. The opening of these valves has no effect due to HV 01-109 being closed.

C. Feedwater

1. Instrument process tubing for FE-06-101A,B,C; a. Function: Monitor feedwater flow between the second and third feedwater heaters in each of the "A", "B", and "C"
feedwater heater strings to control valve FV-C 05-103 in the condensate recirculation line.: b. Failure Effects: A severance of one or more of these '

instrument tubes would result in low flow signal into a 4 flow summer which produces a signal to control the position of bypass valve TV-C 05-103. This would result in an opening of the bypass valve and a possible reduction in feedwater flow. i III. Combined Effects A. A break in any of the Extraction Steam lines results in a loss of ( inventory through one of the moisture separators and could result in ' a combination of a partial loss of feedwater heating, a slight reduction in feedwater flow (though the feedwater controller is not affected), and a turbine trip. If a turbine trip is effected as a result of the HELB and simultan-eous failure of appropriate control systems components, the conse-quences of this event are bounded by the Turbine Trip Without Bypass event analyzed in FSAR 15.2.3. An additional single active failure in a mitigating system also results in a bounded event, as discussed in FSAR 15.2.3.

    .                               It is possible that the ELB will affect the control systems compon-ents in such a manner that a loss of some feedwater heating occurs due to improper valve alignment, and a turbine trip does not occur simultaneously with the ELB.             In this case, the maximum loss of feedwater heating that can occur is less than 30*F, given the worst case combination of failures. A turbine trip on high-high level in at least one of the moisture separators would occur at some time after the reactor stabilized at a power level elevated from its initial value. If turbine trip on high-high level in at least one of the moisture separators does not occur, a turbine trip due to nois-ture carryover to the LP turbines would likely occur at some later time, without operator action.

Such an event may be outside the bounds of the Turbine Trip Without Bypsg) and Loss of Feedwater Heating transient events analyzed in FSAR 45.2.3 due to the elevated power level. However, the effects of this postulated accident are within the bounds' of accident criteria 12-1482 A - 17

                                        . __      _ . _ _ _ _       . _ . _ . _ _ . _   , ~.__ _ ._ ._ _             _   _.. _.

set forth in FSAR Chapter 15. No further analysis of this event is required. See Section 3.0 for additional discussion. B. A break in the high pressure steam supply line. to the feedwater pump turbines will result in a loss of some inventory through the break and could result in a combination of a partial loss of feedwater heating, a slight reduction in feedwater flow, and a turbine trip. The effects of such an event are the same as discussed in A above. C. A break in any Condensate line in this zone constitutes a feedwater line break event. The effects of ' this event are bounded by the Feedwater Line Break Outside Primary Containment event analyzed in FSAR 15.6.6. The failure of any control systems components in the zone will not exacerbate this event. An additional single active failure in a mitigating system also results in a bounded event, as

              .. discussed in FSAR 15.6.6.

D. The Auxiliary Steam system functions are required during reactor startup and pre-startup operations. Such a break could abort a-startup, but would not have an adverse impact on reactor parameters. If the HELB adversely affects the control systems components in the zone, a combination of a partial loss of feedwater heating, a slight reduction in feedwater flow, and a turbine trip could occur. The effects of such an event are the same as discussed in A above. E. A break in any portion of the Turbine EHC Fluid Actuator Supply line will result in a loss of EHC system pressure. This loss of pressure will actuate RPS scram functions on loss of EHC pressure and/or MSV closure. The effects of this event are bounded by the Turbine Trip Without Bypass event analyzed in FSAR 15.2.3. The failure of any control system components in the zone which could possibly be ad-versely affected will not exacerbate this event. An additional single active failure in a mitigating system also results in a bounded event, as discussed in FSAR 15.2.3. O 12-1482 A - 18

J Areas 6,7/ Elevation 217/ Grid MIS I. High Energy Systems A. Main Steam

1. 4" EBD-113

m. Function: High pressure, backup steam supply to the reactor feed pump turbines.

b. Effect of Break: Results in a loss of inventory through the break and a loss of the backup steam supply to the RFFTs.

                    ..                                                                                    ~

B. Extraction Steam

1. 10"/12" GAD-108

a. Function: Low pressure steam supply for the RFPTs from crossaround steam.

b. Effects of Break: Results in a loss of inventory through the break and a loss of the normal steam supply to the RFPTs. The high pressure, backup supply is available.

C. Condensate

1. 14" GBD-113

a. Function: Condensate recirculation line.