Text

High Energy Line Break/Control Sys Failure Analysis
	ML20084J820
Person / Time
Site:	Limerick
Issue date:	04/30/1984
From:	Schroeder R, Schrull E, Strong R; GENERAL ELECTRIC CO.
To:	;
Shared Package
ML20084J817	List: ML20084J814; ML20084J820;
References
	IEIN-79-22, NUDOCS 8405100080
	Download: ML20084J820 (78)
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{{#Wiki_filter:. , . 3. rg HIGH ENERGY LINE BREAK / ! I I CONTROL SYSTEMS FAILURE ANALYSIS REPORT ON LIMERICK GENERATING STATION UNIT I l l PREPARED FOR PHILADELPHIA ELECTRIC CGMPANY l PREPARED BY R. K. SCHROEDER E. D. SCHRULL R. W. STRONG GENERAL ELECTRIC COMPANY NUCLEAR ENERGY EUSINESS GFICATION SAN JOSE, CALIFORNIA l l 8405100080 840504 APRIL 1984 PDR ADOCK 05000352 E PDR 12-1479 (I)

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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). This report has been reviewed and approved by: b . S. H. Slivinsky, Technical eader, Regulatory Compliance Engineering Nuclear Control and Instrumentatiot Product Design Operation M. A. Smith, Manager, Regulatory Compliance Engineering Nuclear Control and Instrumentation Product Design Operation E. C. Eckert, Manager, Plant Transient Performance Engineering Nuclear Power Systems Engineering Department l \ R. R. Bloom (trand, Senior Licensing Engineer, Project Licensing Nuclear Safety and Licensing Operation I l 12-1479 (2)

1.0 INTRODUCTION

Pay 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 l 2.4 Zone Determination 2-7 1 2.5 Pipe Break Location and Effects 2-8 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 12-1479 (3)

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1. 0 - INTRODUCTION 1

1.1 PURPOSE l The purpose of this study was to determine the effects of a High Energy Line Break (HELB) 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 HELB 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 analysis 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 HELB 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 4

HELB zone analysis was performed (Section 2.7) and the results summar-ized in Appendix A. . Final conclusions and recommendations are presented in Section 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 HELB.

events and their limiting effects on the reactor parameters. In most cases, the effects of the postulated HELB/ control systems failures i events are less severe than the Unacceptable Results for Incidents of f Moderate Frequency - Anticipated Operational Transients presented in FSAR Chapter 15. .In all cases, the effects of the postulated events are bounded' by the Unacceptable Results for Limiting Faults. - Design Basis (Postulated) Accidents presented in FSAR Chapter 15. It is 3 concluded' that safe reactor shutdown is assured for all events postu-1ated herein, and the consequences of these postulated' events do not ! result'in any significant risk to the health and safety of the public.

                     .12-1480                                       1-1

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j. 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:

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 energy lines, location of postulated breaks, and evaluation of 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;

4. Perform a plant walkdown to verify the location of the-control 2

systems components and their proximity to high energy lines;

;                         5. Postulate pipe breaks in the zones defined and determine which                             -

! control systems components are affected by each possible pipe j break;

6. Analyze the potential effects on the control systems components: impacted and determine the effects on any controlled components;; 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; i 8. Compare the effects with the -transient and accident analyses in i

Chapter 15 of the FSAR, ccasidering an additional single active i component failure.

                         .9. Identify postulated events that are beyond Chapter 15 analyses and recommend corrective actions.

l 2.1 SYSTEM ELIMINATION l 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).

1. ' Non-electrical ' systems , i.e. , mechanical and ' structural systems I comprised only of structural steel, piping, - tanks, cranes, and )

                               -like equipment are excluded.                                                               .

1 12-1481 2-1 _ _ .-_ __ __ _ ~ . _ _ _ - - _ -_ _ _ _.. _ ,_ _

2. Instrumentation systems with no direct or indirect controlling function (i.e, systems which provide monitoring, status, and alarm indications only) are excluded. Instrumentation and dedicated inputs into the process computer, as well as the process computer itself, are excluded.

3. Control systems which have no direct or indirect interaction with reactor operation or reactor parameters are excluded. Examples are communication, lighting, and external building ventilation systems.

4

4. Control systems that interact or interface with the reactor operating systems directly, but which cannot affect the critical

, reactor parameters either directly or indirectly in the short term are excluded. Systems which can only indirectly affect the reactor parameters through long term effects (such as water quality) are excluded. An example is the Condensate Filter / Demineralizer System. The effects of failures in these systems , will surface slowly in comparison to the dynamic effects associ-i ated with a HELB event.

5. Systems not used during normal operation in the "Startup" or Run" modes are excluded. Normal plant conditions also include opera-tion in the " Refuel" and " Shutdown" modes, however. the fact that there are no high energy lines with the plant operating in these modes precludes the possibility of a HELB event.

6. Electrical systems involved in power generation and distribution, j the loss of which will not impact the ' reactor parameters or safety system performance (e.g., the. station auxiliary ' trans-formers), are excluded.

l The following list details control systems not eliminated via the above criteria. These were included in the HELB analysis. Any systems which could possibly be eliminated, but were questionable, were

retained for analysis purposes.

MPL System

B21 Nuclear Boiler Process Instrumentation B21 Steam Leak Detection-

! C11 Control Rod Drive / Reactor Manual Control D12 Process Radiation Monitoring D22 Area Radiation Monitoring C32 Feedwater Control j B32 Reactor Recirculation / Jet-Pump Instrumentation s C51 Neutron Monitoring G31 Reactor Water Cleanup M01 Main Steam M02 Extraction Steam MOS Condensate M06 .Feedwater M09 Circulating Water i l 12-1481 2-2

                    .       ,,        . - . , . . . -    , , , - -       , , , - . . - .-             . , . . - , , , - . - - - - - - -                 + - .

M10 Service Water M12 RHR Service Water M13 Reactor Enclosure Cooling Water ! M14 Turbine Enclosure Cooling Water

                       -M15          Compressed Air M19          Lube Oil M25          Plant Leak Detection M26          Plant Process Radiation Monitoring

.- M28 Generator Hz Cooling and CO2 Purge M57 Containment Atmospheric Control M59 Primary Containment Instrument Gas M75 Turbine Enclosure HVAC M76 Reactor Enclosure HVAC M77 Drywell HVAC M78 Control Enclosure HVAC M79 Radwaste Enclosure HVAC M87 Drywell Chilled Water Turbine Control Systems Main Turbine Generator System Turbine Bypass System 2.2 COMPONENT ELIMINATION 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-i ing elimination criteria were applied to the remaining components to arrive at the final list of components considered in the detailed HELB 4 analysis. The appropriate system Piping and Instrumentation Diagrams and Elementary Diagrams were used to aid in this clinination.

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 j may be physically located on mechanical components, are included.; 2. Instruments and other dedicated inputs to the process computer are eliminated.; 3. Components which prnvide 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 interlocked with other equipment.
4. Components which provide indication and/or inputs for alarms or recording devices only, are eliminated.

In general, " initiating" type control components such as elements, switches, transmitters, controllers, and converters were included in the detailed HELB analysis, along with their related taps and process tubing. Switchgear and Motor Control Centers (MCC) were included as components subject to failure, and control systems components supplied by the i

             .12-1481-                                       .2 - 3

        .                                                                                         i affected switchgear and MCC were analyzed for loss of power as 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 defin 1 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:

a. Maximum operating temperature exceeds 200*F.

b. Maximum operating pressure exceeds 275 psig.

Those lines that operate above these limits for less than 2% of the time they are required to perform their intended function are classi-fled as moderate energy lines and are therefore excluded from the scope of this study. Piping whose diameter is 1 inch NPS 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. i 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 C1canup From shutdown cooling suction line through RWCU pumps, regenerative and nonregenerative heat exchangers, and cleanup filter /deminer-alizers to feedwater lines 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 containment isolation valve and drain line isolation valves RPV Head Vent Line From reactor vessel head nozzle to main steam line "C" Standby Liquid Control From reactor vessel nozzle to first upstream check valve 12-1481 2-5

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 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 Auxiliary Steam From auxiliary boiler to various steam consum-ing components High Pressure Drains From final feedwater heater to associated drain valve in each feedwater heater string Extraction Steam From main steam line "B" to feedwater pump turbines; from crossaround steam lines to

;                                              feedwater heaters and faedwater pump turbines; j                                               from moisture separators to feedwater heaters and condenser inlet valves; from high and low
!.                                             pressure turbines to feedwater heaters
,           Air Removal                        From main steam line            "C"   to steam seal j                                               evaporator
    .       Turbine EHC                        From electro-hydraulic control power unit to turbine stop valves (NSV's), combined inter-cept valves (CIV's) and bypass control valves 4

I k l 12-1481 2-6

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

2.4 ZONE LETERMINATION 1 The Turbine and Reactor Enclosures for Limerick Unit I were separated l 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 i the defined zone would impact all control system components it. the zone. Using this approach, the effects of pipe whip, jet impingement i 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 , 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-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 major elevation other than that at which the pipe break occurs. The j 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 ! is used. The Analysis Summary in Appendix A reflects this approach.

For the Reactor Enclosure, the zones of influence defined in the FSAR Chapter 3.6 were used. The figures in Appendix B detail the final l zones used for the study.

2.5 PIPE BREAK LOCATION AND EFFECTS i ! 2.5.1 PIPE BREAK LOCATION , ! 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 l in the vicinity of the high energy piping, unless piping runs subject . to high stress have been specifically identified and analyzed as a 1 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 i 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 0

                                                               -_,-y               ,    - - - - -

e 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 condition (i.e. , "Startup" or "Run" mode) for that postulated event. ! l 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-i 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, 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 arc of motion.             The " sacrificial" approach j                     detailed in Section 2.4 envelopes these pipe whip considerations.

l 2.5.2.2 JET IMPINGEMENT CONSIDERATIONS l Jet impingement is considered for both circumferential and longitu-dinal breaks. The' criteria used for evaluating the effects of jet impingement are consistent with those listed in Reference 4. The basic approach assumed is that the jet from a postulated break is 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.

2.6 PLANT WALKDOWN 2.6.1 WALKDOWN PREPARATION 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 12-1481 2-8

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

e

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 energy lines.

, Using the pipe break criteria established in Section 2.5.2, control systems components affected by a HELB were determined for each high 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 were conservatively applied in judging which instrument taps and tubing could be adversely affected. In some cases, no t.igh 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-inated from the detailed analysis since no high energy lines are l routed through these enclosures. The Auxiliary Boiler Enclosure was 1 eliminated since only Auxiliary Steam System components exist within the enclosure. Specific zones of the' Reactor and Turbine Enclosures eliminated are noted in the analysis presented in Appendix A. 2.7 ZONE ANALYSIS The detailed analysis was performed on a zone by zone basis. The , following description is representative of the analysis performed for

;                         each zone. Appendix A, which presents the summary of the analysis for each zone, follows this format.

i . I. High Energy Systems

A list was made which identified all the high energy piping in the zone. Each high energy line was reviewed to determine the 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 l FSAR Chapter 15 event identified, where appropriate. II. Control Systems

A list was made of all control systems components within the zone. The failure mode (s) of each component and the effect(s) of its failure on all controlled components were - reviewed. Con-

trolled components are assumed to operate in the worst possible j mode as a result of the failure.

l' 12-1481- 2-9 l

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 determine 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 exieting analyses. l 12-1481 2 - 10

                                                                  - - - - .            +,

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 l 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 app:ied 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.

i The worst-case combined effects of the postulated HELB and consequen-

' tial control systems failures have been examined. In many cases, the <

postulated HELB 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 HELB 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-

! tional active component failure, which exhibit the same or more severe

effects than the postulated events (i.e., " bounding" events).

3

The worst postulated combination of events presented in the analysis l of Appendix A occurs from a pipe break in the Turbine Enclosure, j Areas 1,2/ Elevation 217/ Grid Q15, the moisture separator drain tank

;                area. A HELB within this zone may cause a partial loss of feedwater i

heating and an eventual turbine trip, if the appropriate instrumenta-tion and controls are disabled leading to improper valve positioning. Using the " sacrificial" approach, which assumes that all control systems components in the zone could fail in the worst possible

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 Steam 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 distance between the two sets of three moisture separators. For this event, the reduction in feedwater inlet temperature causes a i 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-ence a change in the critical power ratio greater than that shown in the Unacceptable Results for Incidents of Moderate Frequency - Antici- ! pated Operational Transients of FSAR Chapter 15, but only for a short ! time. However, the effects of this accident event, even considering an additional single active component failure, pose no threat to the i Unacceptable Results for Limiting Faults - Design Basis (Postulated) Accidents presented in the FSAR, Chapter 15. , i 12-1545 3-1

J All other " Combined Events" are bounded by the accident and transient events analyzed in FSAR Chapter 15, as noted in Appendix A. I t' 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. i ) 4 j. l i 12-1545 3-2

4.0 REFERENCES

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": Drawina Revision

A-305 10 A-306 9 A-307 7 A-308 7 A-309 7 A-310 6 A-311 5 4

l l 12-1546 41 i

I (Reference 5, Continued) Bechtel Power Corporation, " Instrument Location Drawin8s": Drawina Revision Drawina 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 M-191 7 M-193 22 M-195 56 M-196 28 12-1546 4-2

(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 4 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-752 8 M-687 6 M-753 7 M-688 4 M-754 9 M-689 10 H-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 / l 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 M-720 17 M-721 12 M-722 6 M-723 15 M-724 12 M-725 11 12-1546 4-3

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

4' i 3

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I- ~6. General Electric - LSTG, "High Pressure Hydraulic Fluid Piping" . j- Diagrams: l J t t. Drawina- Revision. l

l. 824E519 3 i l' 838E889 2 >

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f 4 e l APPENDIX A ANALYSIS SUtefARY 12-1482 A-1 I L ._ , .. .

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

Zone Eliminated (?) Reason 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 Area 8/ Elevation 200/ Grid M21 Yes 2 I Area 1/ Elevation 217/ Grid Q6 No 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 MIS No Area 8/ Elevation 217/ Grid M21 Yes 1 Area 1/ Elevation 239/ Grid Q7 Yes 1 i Areas 1,2/ Elevation 239/ Grid P14 No Areas 2,3/ Elevation 239/ Grid P20 Yes 1 Area 6/ Elevation 239/ Grid M7 No Areas 6,7/ Elevation 239/ Grid M12 Yes 2 I Area 7/ Elevation 239/ Grid M16 Yes 2 I 12-1482 A-2 L

l Zone Eliminated (?) Reason Areas 6,7/ Elevation 239/ Grid J14 Yes 1 l 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 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 H23 Yes 1 Area 8/ Elevation 350/ Grid K(f)23 Yes 1 l l l i 12-1482 A-3

  .   ~

Area 2/ Elevations 189,200/ Grid Q155 s I. High l'nergy Systems A. Extraction Steam = _

1. 10" GBD-103

a. Function. Six lines designated GBD-103 carry inventory from the .six moisture separator drain tanks to feedwater 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 eventx(FSAR 15.1.1).

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

i

a. Function: Six linas tap off from the six 10" GBD-103 condensate lines . discussed above. These lines carry inventory from the poisture separator drain tanks to the high pressure o.r low pressure condensers. These lines are hign' 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-toes 4 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).

B. Condensate, '

    ,                   1.         30" GBD-116
                                                                                                       \
                                                               ~

i a. Fonction: Condensatn Aupply line ,from the condensate filter:demineralizers to the inlet nozzle of the feedwater drain'ecclers '1AE107,1BE107, and ICE 107.

b. Effect' of Bresk: 'Line break ' results in a feedvater line break ' everm The effects of1this break are bounded by the l Feedwater Line Break '- wtside Primary Containment evert (FSARL15.6.6) : . ,

w - I, 2. MI' GBD-117 H

                                                                 '                           \

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                                                                                              , ,,,t l

a. Function: Three lines ?derignated GBD-117 carry condensate l , froa- the. tnree drain' coolers to 'the first 'feedwater heater q,, ' in, e'ach string of heaters. r, n {1 : .

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12-1482 9 ,' Y

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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).

C. Auxiliary Steam

1. 8" GBD-176

a. 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.

II. Control Systems A. Extraction Steam

1. ZS-02-112C,113C

a. Function: Control position of level control valves LV-C 02-112C and 02-113C which are normally open, fail closed 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 inventory through the Main Steam system, and a reduction in feedwater heating. Closure of the valves in the lines supplying extraction

   ,                  steam to the 14CE104 feedwater heater could result in an additional 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 line break in this zone is bounded by the Feedwater Line . Break Outside Primary Containment event analyzed in FSAR 15.6.6. The 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 1

f

                                                                                                                  -                                                       ~'

components in the zone, a, partial loss of feedwater heating (<100'F) . , The effects of this event are bounded by the I.oss of ' could result. Feedwater IIeating event analyzed in FSAR 15.1.1. An additional single active failure in a r.itigating system also results in bounded event, as discussed in FSAR ,15.1.1. ,.

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Areas 2,3/ Elevations 189,200,217/ Grid R20 V I. High Energy Systems A. Auxiliary Steam

1. 12" GBD-176; 4" GBD-135 i a. Function: Provide steam for heating the LP, IP, and HP l

condenser shells on the low pressure turbines "C", "B", and "A", respectively. i

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

B. 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 4

such a break are bounded by the Feedwater Line - Break Outside Primary Containment event (FSAR 15.6.6). II. Control Systems A. Condensate

1. HY-05-110A,B,C; XC-05-110A-1,A-2,B-1,B-2,C-1,C-2

     .                                   a.        Function:     Control    normally-closed,    fail-open   valves (HV-C 05-110A,B,C)     on the 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 >

normally closed valve upstream. (i.e. , closer to the ad n steam tapoff) than the controlled valves such that'there is no steam downstream of HV 01-109. l b. . Failure Effects: Instrument -failure could cause the HV-C 05-110 valves to open during a time when - they are normally closed. The opening of these valves has no effect due to HV 01-109 being closed. HV 01-109 is unaffected. i

2. PSL-05-107,108

a. Function: Monitor pressure on condensate ' pump "A" dis-I charge and control valves LV-C 05-104 (fail-closed) in the

                     . 12-1482'                                       A'- 7

l condensate rej ect line and FV-C 05-103 (fail-open) in the l condensate recirculation line. I b. Failure Effects: Failure of both pressure switches would generally result in closure of LV-C 05-104, the reject 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 recirc and reject lines, a larger reduction in feedwater flow would be realized. III. Combined Effects A. The Auxiliary Steam system functions are required during reactor

!                                         startup and pre-sta rt.up operations.      Such a break could abort a startup, but would not adversely impact the reactor parameters. A break in this system in this zone which affects the control system components in the zone could result in a loss of some feedwater flow.

The effects of this partial loss of feedwater flow are bounded by the i 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. - i B. A break in the Condensate system piping in this zone 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 system components within this zone. An additional single active failure in a mitigating system also results in a bounded event, as discussed in FSAR 15.6.6. l 1 l 12-1482 A-8

          .     .                         -    -_=

Areas 6,7,2/ Elevation 200/ Grid M12 1 I

1. High Energy Systems !

A. Condensate

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

a. Function: Condensate supply lines from the steam packing exhauster through the condensate filter demineralizers to the feedwater drain coolers.

b. Effect of Break: A break in this line results in a loss of condensate supply to the Feedwater system. This break is bounded by the Feedwater Line Break Outside Primary Con-tainment event (FSAR 15.6.6).

2. 12" GBD-115

a. Function: Condensate reject line.

b. Effect of Break: A b reak in this line results in a loss of some condensate supply to the Feedwater system. This break is bounded by the Fcedwater Line Break Outside Primary Containment event (FSAR 15.6.6).

B. Auxiliary Steam

1. 10" JBD-7

a. Function: Supply steam to the condensate storage tank (CST) and refueling water storage tank heaters.

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

2. 4" GBD-136

a. Function: Test steam supply for the RCIC and HPCI turbines.

b. Effect of Break: Loss of test steam supply to RCIC and HPCI turbines. Line is blind flanged - during operations ,

other than testing. ,l II. Control Systems A. Extraction Steam l

1. HY-02-115

a. Function: ' Controls one normally closed, fail open valve.in a 2" line from the HP turbine to the HP condenser.

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                                                                                                       -l i            12-1482                                   A-9.                                                i I                                                                                                          I L                                                                                                          !
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b. Failure Effects: A slight loss of feedwater heating

(<100*F) would result if the valve were opened during normal operation. B. Condensate

1. LT-05-101A,B

a. Function: Control throttle valves which are fail-closed I 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 the condensate reject line.

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

1. PSL-06-102A,B,C

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

b. Failure Effects: Failure to provide the trip signal may result in pump cavitation and loss of feedwater flow.

Failure of the components such that a trip signal is

                                               - generated would result in a loss of feedwater flow.

2. FT-06-101A,B,C

a. Function: Control the condensate recire flow control valve to the LP condenser shell on 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 possible reduction of feedwater flow.

                       '12-1482                                   A - 10

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

W

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.

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 demineralizers and the Air Removal and Sealing Steam system.

l 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. E. Compressed Air

1. PC-15-150

,                            _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.

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.

F. CRD Hydraulic

1. PSL-46-N001A,B

a. Function: Control the CRD drive water pump flow from the condensate reject line to the HCUs.

b. Failure Effects: Only long term operation .of the HCUs 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 by the Feedwater: .Line Break Outside Primary Containment event ! 12-1482 A l.

l

         .                                                                                  1 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-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 siiscussed in FSAR 15.2.7. - 6 i 12-1482 A = 12

Area 1/ Elevation 217/ Grid Q6 I. High Energy Systems A. Turbine Electro-Hydraulic Centrol (EHC)

1. I "/2" FAS, Fluid Actuator Supply

a. Function: High pressure fluid lines serve to maintain the i 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 scram. Reactor scram is RPS (Reactor Protection System) scram on loss of EHC pressure and/or closure of the MSV's.

II. Control Systems A. Service Water I 1. TE-10-106A,B; TIC-10-106A,B

a. Function: Control valves TC-V 10-106A,B (normally open, 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 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 compon-ents in the zone which could possibly be adversely affected will not i exacerbate this event. An additional single active failure in a mitigat-ing system also results in a bounded event, as discussed in FSAR 15.2.3. { l~ 12-1482 A - 13

1 Areas 1,2/ Elevation 217/ Grid Q15 I. High Energy Systems , A. Extraction Steam

 ,                     1.       10" GAD-108 a.

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

b. Effect of Break: Loss of inventory through the break and a loss of low pressure steam supply to the feed pump tur-bines. The high pressure backup supply is available.

2. 10" GJD-101

a. Function: Two lines designated GJD-101 supply feedwater heater 14CE104 with steam from two moisture separators.

b. Effects of Break: Loss of inventory through one moisture -

separator and a loss of some (<100*F) feedwater heating. The effects of this break are bounded by the Loss of Feed-water Heating event (FSAR 15.1.1).

3. 10"/8" GBD-103

a. Function: Six lines designated GBD-103 carry inventory from the six moisture separator ' drain tanks to feedwater heaters 14AE164, 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).

4. 6" GBD-131; 6" GBD-133

a. Function: Six lines tsp off . from the six 10" GBD-103 condensate lines discussd above. These lines carry

inventory from the - moisture separator drain tanks to the.

I 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-l tors and a loss of some (<100*F) feedwater heating. The-l effects of. this break are bounded by the Loss of Feedwater Heating event (FSAR 15.1.1).

12-1482. _ A'- 14

B. Main Steam

    .                                                                                               I

1. 6"/4" EBD-113

a. Function: High pressure steam supply for the three reactor feedwater pump turbines. This is a backup steam supply.

b. Effects of Break: Loss of inventory through the main steam system and a loss of the backup high pressure steam to the feed pump turbines.

C. Feedwater

1. 20" GBD-116

a. Function: Condensate supply line from the condensate filter demineralizers to the inlet nozzle of the feedwater drain coolers IAE107, 1BE107, 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 feedwater from the three drain coolers to the first feedwater heater 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 Feedwater Line Break Outside Primary Containment event (FSAR 15.6.6).

D. Auxiliary Steam

1. 6" GBD-146

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

b. Effect of Break: A break in this line may abort a startup, but will not adversely affect the reactor parameters.

I E. Turbine Electro-Hydraulic Control (EHC) l

1. 1\"/2" FAS, Fluid Actuator Supply

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 contral valves.

k 12-1482~ A - 15

o ,.

b. Effect of Break: Loss of EHC system pressure resulting in

    .                              reactor scram. Reactor scram is RPS (Reactor Protection System) scram on loss of EHC pressure and/or closure of the MSV's.

II. Control Systems A. Main Steam l 1. LT-01-101A-F; LT-01-103A-F

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 controlled valves in the lines to the condensers (LV-C 01-103A-F) are nor-

!                                 mally closed and fail open.              The controlled valves in the 1

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 l l 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

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 l 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 l l

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

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. Feec' water

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 flow summer which produces a signal to control the position of bypass valve FV-C 05-103. This would result in an opening of the bypass valve and a possible reduction in feedwater flow.

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-cous 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 HELB 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 HELB. 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 l 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.

l Such an event may be outside the bounds of the Turbine Trip Without Bypass and Loss of Feedwater Heating . transient events analyzed in FSAR 15.2.3 due to the elevated power level. However, the effects of this postulated accident are within the bounds of accident criteria l 12-1482 -A - 17

i 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 reduc. ion 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 cculd 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.

3 i 3 l i l I' 12-1482 :A - 18

Areas 6,7/ Elevation 217/ Grid MIS

    .                                                                                               l I. High Energy Systems A. Main Steam

1. 4" EBD-113

a. 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 RFPTs.

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 i

a. Function: Condensate recirculation line.