ML20236M366
| ML20236M366 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 06/11/1987 |
| From: | Beebe H SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | |
| Shared Package | |
| ML20236M344 | List: |
| References | |
| ECN-A-5415, ECN-A-5415-R03, ECN-A-5415-R3, TAC-64359, NUDOCS 8708110035 | |
| Download: ML20236M366 (119) | |
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-3.s DESIGN BASIS REPORT -.../ 4 May 9, 1?S7
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a.m ig A-5415, Rev. 3 N/A 104415
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- l. PURPOSE OF DESIGN CHANGE:
See Attacned
- 5. DESIGN CRITERIA USED:
See Attached
- 63. CALCULATIONS & DESIGN INFORMATION:
See Attached .
IV. FAILURE MODES:
C TMS CHANGE DOES NOT AFFECT COPUROL ROOM INSTRUMEN"!ATION X% THIS CHANGE AFFECTS CONTROL ROOM l INSTRUMENTATION. SEE ANALYSIS V.- SPECIAL MAINTENANCE. REQUIREMENTS:
See Draft Test Specification Surveillance Requirements; Reference 11 VI. SPECIAL OPERAT'NG REQUIREMENT 3. ,
See Attached Vit. VERIFICATION dRITERIA:
SeeAitached V!!E COMMENTS:
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-1 COGNIZANT ENGINEER'S CHECKLIST ,
DESIGN BASIS REPORT-Cognizant Engineer- Person. Responsible indicates by "Y" @t' program or "N" programs initials items requiring review marked "Y" L Design Considerations. -
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0 USAR Comitments C Nr3 f fjg 0 Fire Protection- G _ '.)] my y 9 0 SafetyImpactPrograar(II/I) - h n a
, , , m u m - n a c. i cwa emuo ~u ee 0 Electricai Cable and Raceway
. Separation Program- /wrrd' 0 Radiological Considerations /
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/v - f'nl87 l- ALARA 0 Environmental Qualifications. ~2fX. )
- Seismic Qualifications Ng. g,p 0 Human Factors W 5l,qhy 0 Reg Guide 1.97'
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l TABLE OF CONTENTS, J
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02 f PREFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l 02 I
I . P U RPO SE OF D E S I GN C HANGE . . . . . . . . . . . . . . . . . . . .
05 I I I . DE S IGN C RITE R I A . . . . . . . . . . . . . . . . . . . . . . . . 1 05 I I . A.
SUMMARY
OF C HANGE . . . . . . . . . . . . . . . . . . . . . .
19 (
I I . B . D E S I GN B AS I S . . . . . . . . . . . . . . . . . . . . . . . . .
24 f II.C. SCOPE . . . . . . . . . . . . . . . . . . . . . . . . . . . .
24 II.D. EQUIPMENT CLASS & POWER REQUIREMENTS . . . . . . . . . . . . .
24 II.E. TESTING . . . . . . . . . . . . . . . . . . . . . . . . . . .
26 III. CALCULATIONS AND DESIGN INFORMATION . . . . . . . . . . . . . .
26 III,A. DESIGN FEATURES . . . . . . . . . . . . . . . . . . . . . . .
26 III.B. FUNCTIONAL DESCRIPTION . . . . . . . . . . . . . . . . . . .
,26 i i
III.C. DESIGN CALCULATIONS . . . . . . . . . . . . . . . . . . . .
26 l I I I . C .1, AF W FL OW . . . . . . . . . . . . . . . . . . . . . . . . .
27 {
III.C.2. CONDENSATE STORAGE TANK CAPACITY . . . . . . . . . . . . .
27 f III.C.3. EFIC SETPOINTS . . . . . . . . . . . . . . . . . . . . . .
28 III.C.4. STEAM GENERATOR LEVEL CONTROLS . . . . . . . . . . . . . . l' III.C.5. MAIN FEEDWATER OVERFILL . . . . . . . . . . . . . . . . . . ?8 29 III.C.6. LOMFW ANTICIPATORY TRIP . . . . . . . . . . . . . . . . .
30 III.C.7. AFW PUMP RUNOUT 1 30 III.C.8. EFIC AFW POWER SOURCES . . . . . . . . . . . . . . . . . .
31 III.C.9. UPGRADE AFW RELIABILITY 32 III.C.10. HELBA & MISSILE STUDIES . . . . . . . . . . . . . . . . .
33 III .C.11. EFIC SHUTDOWN BYP ASS. . . . . . . . . . . . . . . . . . .
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' - . TABLE OF CONTENTS ;
33 IV. FAILURE MODES . . . . . . . . . . . . . . . . . . . . . . . . .
34 IV . A AFW V ALVE F AILU RE . . . . . . . . . . . . . . . . . . . . . . .
35 IV.B FAILURE OF FIBER 0PTIC CABLES BETWEEN CHANNELS . . . . . . . . .
37 IV.C F AILURE OF RPS INPUTS TO EFIC . . . . . . . . . . . . . . . . .
I 38 l
! IV.D FAILURE OF SFAS INPUT TO EFIC . . . . . . . . . . . . . . . . .
39 IV.E F AILURE OF EFIC TRIP INTERFACE EQUIPMENT . . . . . . . . . . .
.... 39 IV.F EFIC POWER SOURCE FAILURES . . . . . . . . . . . . . . 1 41 IV.G EFIC CONTROL F AILURE . . . . . . . . . . . . . . . . . . . . .
44 l l
VI. SPECIAL OPERATING REQUIREMENTS . . . . . . . . . . . . . . . . .
44
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VI.A OPERATING DESCRIPTION OF EFIC CONTROLLED DEVICES . . . . . . . ,
48 VII. VERIFICATION CRITERIA . . . . . . . . . . . . . . . . . . . . .
48 I VIII. COMMENTS ..........................
48 VIII. A DESIGN VERIFICATION . . . . . . . . . . . . . . . . . . . . .
49 VIII.B DIFFERENCES BETWEEN R.S, CR-3, AND ANO EFICS . . . . . . . .
53 VIII.C USE OF ORIGINAL PLANT VALVES . . . . . . . . . . . . . . . .
54 FIGURE VI - EFIC CONTROLS ON HISS (E) . . . . . . . . . . . . . . .
55
. . . . . . . . . . . . . . . . . . . . . i TABLE VI - EFIC CONTROLS 57 LIST OF REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . .
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l l REVISION PAGE j ITEMS PAGES REVISION DATE l 3 5/7/87 Added Revision Page, Changed AFW Flow 22, 26, 58, 59, 60 4
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NCF Work Reques" 104415 ECN A-5415 MAJOR !
6 001 Date 5-8-87 Discipline _ I & C MOD ,
PREFACE This DBR covers the Emergency Feedwater Initiation and Control System l (EFIC) and its functional ties to associated equipment. That is, it l ;
covers the concept and equipment design of EFIC and the Trip Interf ace l
Equipment (TIE) as well as the functional requirements imposed by EFIC on equipment which interfaces directly with EFIC or the TIE, or is otherwise included in Mod 1. Other than EFIC and TIE cabinets, this DBR does not 3
attempt to address component specific design criteria or design information associated with new equipment (or changes to existing ;
equipment) except when such criteria or information directly impacts the ;
function of EFIC. For instance, this DBR explains that EFIC requires-Steam Generator level taps at 6",156", and 619", but does not cover the l specific designs of the new level taps. That tap design and its attendant calculations is covered by the CBR for sub-ECN A-5415A.
Another example would be that this DBR covers required channel separation for cabling between EFIC and equipment connected to it. However, the i actual cable routing and separatian studies showing that the required i separation has been maintained, is to be covered by the appropriate '
sub-ECN. Another example is that this DBR covers the functional necessity to have two nomally open, fail open, control valves in j parallel (each with a motor operated isolation valve in series) feeding J AFW to each steam generator. However the seismic design of the modified l piping and valves would be covered under the sub-ECN which installs the l valves ( A5415 J),
The scope of each sub-ECN can be found in the major ECN A-5415. l I. PURPOSE OF DESIGN CHANGE:
Several severe transients at nuclear power plants with Babcock &
Wilcox supplied NSS's which occurred during the 1970's were caused by l j
inappropriate, post reactor trip, steam generator feedwater and/or !
steam pressure control. Reactor Coolant System overcooling at '
Rancho Seco and Crystal River 3, undercoolings at Davis-Besse and TMI-2, and others were investigated by the NRC in the spring of l 1980. The transients and suggested plant alterations are sammarized l in NUREG 0667, " Transient Response of B&W Designed Reactors." In summer 1980 following issuance of NUREG 0667, and in the hiatus between TMI Short-Tem lessons learned (NUREG 0578) and the clarification of TMI Action Plan Requirements (NUREG 0737) SMUD l agreed in discussions with the NRC to install "EFIC" and to upgrade j
' th2 AFW system to substantially comply with the NRC: " Standard Review Plan" for auxiliary Feedwater Systems (NUREG 0800, Section 10.4.9).
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T L,' ' ECN A-5415 MAJOR NCr - Bork Request ~ 104415 1 Discipline f&C MOD,_ 001 Date 5-8-87 ,
l A conceptional design for EFIC and its related plant modifications was submitted in draf t form to the NRC in October of 1980 and a preliminary Safety Evaluation Report based on a point by point comparison with SRP 10.4.9 was received from the NRC in January 1981. The salient features of the design at that time were to provide:
o Assured redundant availability of automatically initiated AFW for all AFV design basis events. l o Redundant safety grade control of AFW to assure sufficient but not excessive AFW flow. l I
o Isolation of Main Feedwater (MFW) and AFW to prevent continued feeding of a Steam Line Break (SLB) inside containment.
o Failsafe control of ADV's to prevent "mid-range" failure on loss )
of control power and to prevent comon mode f ailure which would ;
open ADV's on both main steam lines. i Following the District's initial commitment to install the Mod 1 changes, several licensing issues have been resolved by inclusion of the specific licensing requirement into the design base of Mod 1.
Thus, the Mod 1 (EFIC) responsibility to resolve NUREG 0737 II.E.1.1, l II.E.1.2.1, and II.K.2.10 ( AFW reliability, saf ety grade AFW initiate, and Anticipatory Reactor trip.on loss of MFW), and portions ,
! of Reg Guide 1.97 (class I Steam Generator level and pressure indication).
Listed here is pertinent licensing correspondence:
- 1. SMUD to NRC letter dated May 6,1980; Responds to IE Bulletin 80-04 Steam Line Breaks in Containment.
- 2. SMUD to NRC letter dated October 6,1980; Correction of ADV f ailure mode on loss of NNI or ICS power.
I 3. NRC to SMUD letter dated January 22, 1981; Preliminary Safety Evaluation Report of AFW upgrade.
- 4. NRC to SMUD letter cated July 10, 1981; Order letter to comply with NUREG 0737.
l 5. SMUD to NRC letter dated September 8,1981; Submitted AFW System Description (B&W Document No. 15-1120580-01) as AFW upgrade design; also submitted upgraded AFW reliability analysis.
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I&C 001 Date 5-8-87 ]
Discipline MOD I
- 6. SMUD to NRC letter dated April 15, 1982; Clarifies use of Flux vs. MFW flow as ultimate Anticipatory Reactor Trip (NUREG 0737 II.K.2.10).
- 7. SMUD to NRC letter dated July 6,1082; Responds to IE Bulletin 81-14; Seismic Qualification of AFW System.
I 8. NRC to SMUD letter dated September 7,1982; Safety Evaluation Report of upgraded AFW system (per AFW System Description B&W Document 15-1120580-01).
- 9. SMUD to NRC letter dated October 22,10*2; Clarifies intent of j
District response to 0737 II.E.1.2.1 and 1.2.2; Asserts SMUD
' ability to alter de.,ign f rom SER'd version of AFW upgrade.
- 10. NRC to SMUD letter dated November 12, 1982; SER of Seismic l
design of the then " current" AFW system.
- 11. SMUD to NRC letter dated February 18, 1983; Supplies additional AFW design basis infonnation.
l 12., NRC to SMUD letter dated April 71983; 5.E.R. for 0737 II.E.1.1 l
' but with three open items.
! 13. SMUD to NRC letter dated April 28, 1983; Submitted B&W Document 15-1120580-03 as latest design for AFW upgrade.
- 14. NRC to SMUD letter dated September 26, 1983; SER for 0737 II.E.1.1 but with one exception.
- 16. SMUD to NRC letter dated January 17, 1986; Brief statement of Cycle 8 EFIC scope.
- 17. SMUD to NRC letter dated March 3,1986; Clarification of Cycle 8 EFIC.
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NCr^ Work Reques* 104415 ECN A-5415 MAJOR I&C 001 Dato 5-8-87 Discipline MOD II. DESIGN CRITERIA II. A. Summary of Chance II.A.l. This modification will place into service the Emergency Feedwater Initiation and Control System (EFIC). EFIC is a four channel electronic logic and l l
control system designed to meet IEEE 279 requirements for redundancy, channel independence, testability, etc. The principal functions of EFIC are to "initiata" AFW, to control AFW flow to assure )
l sufficient (and not excessive) flow, to detect a leak in the Main Steam System (as indicated by low pressure in either Steam Generator), to isolate Main Feedwater (MFW) to a depressurized or overfilled Steam Generator, to control the Atmospheric Dump Valves ( ADV's), and to assure that AFW is fed only to an operable (ie. not depressurized) Steam Generator. ,
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II.A.2. To support the EFIC and its required functions the following changes will be made: l II.A.2.1. Install level sensors on the steam generators and pressure sensors on the l main staca lines. Specifically, this l includes: r l
II.A.2.1.1. Install level taps and root valves in two placer on the l secondary side of each steam generator at 156" above the l top of the lower tube sheet and two places at 619" above ;
the top of the lower tube sheet.
II.A.2.1.2 Install four wide range level transmitters on each steam generator between taps at 6" and 619" (LT-20507A, B, C, D and LT-20508a, B, C, D).
i Install four low range level transmitters on each steam generator between taps at 6" and 156". (LT-20505 A,B,C,0 and LT-20506 A,B,C,D) .
Transmitters shall be grouped as indicated on Fig. 3.1-1 sheet 2 attached to EFIC AFW System Description (Ref. 28).
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II.A.2.1.3 Install four pressure transmitters to each main steam line (outside {
i containment). (PT-20546 A,B,C,0 and PT-20545 A,B ,C,D) . Transmitters grouped as showr. on Fig. l 3.1-1 Sheet 2 (Ref. 28). l l
II.A.2.1.4 One wide range and one low range steam generator level j transmitter, and onc steam l generator pressure transmitter '
i will be connected to each of the four EFIC channels. Power for the transmitters is supplied by the respective EFIC channel.
II.A.2.2 Provide non-interruptable Class 1, AC power j to EFIC Cabinets H4FWA, H4FWB, H4FWC, H4 FWD l and reliable AC power to the non-1E portion of H4FWC and H4 FWD. Provide power to the Trip Interf ace Cabinets H4EI Al, H4EI A2, z H4EIB1 and H4EIB2. )
II.A.2.3 Install the electrical and fiberoptic connection between the EFIC cabinets (H4FWA, B,C and D) and to the Trip Interf ace Cabinets (H4EIA1, H4EIB1).
II.A.2.4 1E connections between the four EFIC cabinets and the plant computer (IDADS) shall be made {
to monitor all EFIC analog indications (24 total signals). Isolated outputs of the EFIC and TIE annunciations will also require connection to the plant computer. Indication out of the TIE that EFIC has started the AFW pumps will be annunicated in the control room and indicated on H2SF. Indication out of the TIE that EFIC has isolated MFW will be annunicated in the control room. I II.A.2.5 Implementation of NI/RPS changes. B&W Field l Change Package 3473 changes the RPS to accept MFW flow signals; to develop a reactor power to MFW flow reactor trip (See figure 4.2.1 or REF. 28); to output power /MFW flow trip, RCP running status, channel bypass, and loss of MFW Pump Anticipatory Reactor Trip infomation to EFIC. Although the power /MFW flow trip modules will be installed, it will not be used by EFIC at this time.
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Work Requesm104415 Discipline I&C MOD 001 Date 5-8-87 II.A.2.5.1 Modify the B&W NI/RPS Field Change Package FCP-3473 such j that Reactor Power vs. MFW flow l
trip logic does not trip the reactor. l l )
II.A.2.5.2 Jumper the power /MFW flow inputs at EFIC so that they will not actuate EFIC.
II.A.2.5.3 Adapt Field Change Package FCP-3473 to conform to existing NI/RPS module and tenninal block layout. Modify RPS seismic and thermal analyses to conform to revised layout.
j II.A.2.5.4 Install the RPS Field Change l
l Package hardware.
II.A.2.5.5. Connect the NI/RPS outputs to their respective EFIC channels and tr. the Plant Computer (IDADS) as appropriate. .
I II.A.2.6 Implement B&W SFAS field change package FC-3478 Revision 5 and upgrade seismic analysis to conform to actual SFAS system configuration. The B&W Field Change Package Changes the SFAS to output to EFIC a signal to start AFW on low RC pressure and/or high containment pressure.
Indication that SFAS has signalled EFIC to start AFW and that EFIC has started AFW will be displayed on H2SF.
II.A.2.7 Delete SFAS control functions for P-319, SFV-30801, SFV-20577, and SFV-20578 f rom H2SF.
II.A.2.8 Modify AFW pump P-319 to receive a priority start signal from TIE cabinet H4EIA1. Manual start /stop controls will be installed on H1SS i in the Control Room. All other start /stop l controls will be deleted except pump / motor protection and diesel generator N.S. Bus loading logic.
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Discipline I&C MOD 001 Date 5-8-87 II.A.2.9 The AFW pump turbine steam inlet valve l HV-3r301 (Formerly SFV-30801) controls shall be modified to receive a priority open signal from TIE cabinet H4EIBl. The SFAS auto start control f or HV-30801 will be deleted.
II . A.2.10 Implement miscellaneous changes to EFIC to l accommodate Rancho Seco control configuration and to add initiation time delay module.
Specifically, modify the EFIC to implement the following items:
Make wiring changes necessary to provide for transfer of control from the Control i Room to the shutdown panel and to provide !
isolation of EFIC from the control room to meet Appendix R requirements for safe shutdown in the event of fire in the l control room.
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Change the color of some of the LED
' indicators on the EFIC panel fronts to improve readability.
l Make wiring changes to provide vector enable directly from the AFW trip initiate modules and to provide only control enable from the C/V Enable (to be renamed Control Enable) trip module.
This gives the capability to reset the Vector enable without resetting the control enable.
Install jumpers on any unused inputs that are fail actuated (i.e. ARTS 1, ARTS 2 and power /MFW flow trip).
Make wiring changes necessary to provide separate annunciation for the non-lE power supply and the lE power supplies.
Modify the shutdown bypass pennissive circuitry such that bypassing is possible when either SG pressure is below bypass setpoint.
l Disconnect the overfill inputs f rom the vector logic. This will disable the -
automatic isolation of auxiliary feedwater on steam generator overfill.
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' Discipline - I_ & C MOD 001. Date 5-8-87 Implement an overfill bistable circuit for use in monitoring S.G. overfill setpoint without risk of spurious EFIC initiates.
Add the spare fiber optic cables between EFIC channels so they will be installed spares.
Install time delay modules in each EFIC cabinet such that the outputs of the following bistables can be delayed by an adjustable time of 0.0 to 9.9 seconds:
SGA Low Level, SGB Low Level, SGA Hi Hi Level, SGB Hi Hi Level, SGA Low Pressure, ,
SGB Low Pressure, SGA Pressure less than SGB Pressure, and SGB Pressure less than SGA Pressure.
Note that installation of the time delay circuits is desirable but not critical tc the operability of EFIC.
II.A.2.ll Modify controls for AFW Flow Test Valve FV-31855 to allow modulating control from the control room with position indication and priority close commands from TIE Cabinets H4EIA1 and H4EIB1 upon AFW initiate.
II.A.2.12 Disconnect ICS control to tne atmospheric dump valves and connect ADV's to EFIC control.
PV-20562 A,B and C will be connected to EFIC channel B. PV-20571 A,B and C will be connected to EFIC. channel A. Existing f manual / auto stations on HlRI will be removed.
New manual / auto pressure control stations will be mounted on the control room panels HlRI and l f
the shutdown panel; one set for SGA, one set l for SGB.
II.A.2.13 Reconfigure the AFW control and isolation valves to add isolation valves in series with existing AFW control valves FV-20527 and FV-20528. Add control valves in series with existing AFW valves SFY-20577 and SFV-20578.
This gives for each Steam Generator redundant parallel control valves each with independent isolation.
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I&C 001 Date 5-8-87 Discipline MOD II. A.2.13.1 Controls for air operated valves FV-20527 and FV-20528 shall be from EFIC Channel "A" only, via the Class 1 electric / pneumatic converters FY-20527 and FY-20528. Both valves will be normally open, fail open on loss of signal l or loss of air. Actual valve position for both valves will <
' be available in the control room on HISS.
Though normally supplied with regular plant instrument air, a seismic Class I (non-interrupted on loss of offsite power) source of air will power the valves for two hours if necessary.
II. A.2.13.2 Controls for 0.C. powered Valves FV-20531 and FV-20532 shall be from EFIC Channel "B" only, via transducers l
' FY-20531 and FY-20532 respectively. Actual i
! Position indication will be indicated in the control room on HlSS, Both valves will be l normally open, fail open on loss of control signal or power. Valve power and position indication shall be powered from the same D.C.
bus which supplies power to EFIC channel "B".
l l II.A.2.13.3 Controls for valves HV-20577 (fomerly SFV-20577) and HV-20582 will be from the control room and EFIC channel "D". Valves are normally closed. HV-20582 and HV-20577 will be powered by a non-interruptable Class 1 l D.C. power source.
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Discipline 1&C MOD 001 Date 5-8-87 II.A.2.13.4 Control for valves HV-20578 i i
(formerly SFV-20578) and !
HV-20581 will be f rom the
' control room and EFIC channel "C". Valves are normally closed. HV-20581 and HV-20578 will be powered by a non ;interruptable Class 1 D.C. power source.
II.A.2.14 Connections f rom EFIC '%" to the shutdown panel will be made t3 accommodate cooldown of the plant with a fire in the control room. Steam generator A and B pressure indication, full range level indication and hand / auto controls for valves FV-20527, FV-20528, PV-20562A, B, C and PV-20571 A, B, C will be required at the shutdown panel. Isolation switches for EFIC and EFIC controlled componets will be added as appropriate for Appendix "R" isolation of components affected by a fire in the Control Room.
II.A.2.15 Modify control of the main feedwater control and block valves to accept a l
' priority close signal f rom the Trip Interf ace Equipment (TIE). Class 1 Solenoid Valves which close FV-20525, ,
FV-20575, FV-20526, and FV-20576 should be )
commanded from TIE cabinet H4EI A1. Valves HV-20529 and HV-20530 to be powered f rom emergency bus $2A3 will receive close comands f rom TIE Cabinets H4EIA1.
II.A.2.16 Add motor operators to valves FWS-015 and FWS-016; renumber valves to FV-23515 and FV-20516 respectively. These two motor operated valves should be operable from the main control room with a priority l
close signal from TIE cabinet H4EIBl.
l Class 1 power to these valves will be f rom emergency bus $2B3.
II.A.2.17 Add a motor operated isolation valve (HV-20521) on 10" line 20529 to isolate Turbine Bypass Valves PV-20561 and PV-20563. Valve power should be Class 1 backed by diesel GEA with manual open/close controls from the control room.
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1 II.A.2.18 Add.a motor operated isolation valve HV-20522 on line 20530 to isolate Turbine Bypass Valves PV-20564 and PV-20566.
Valve power shall be Class 1 backed by l I
diesel GEB with manual _open/close controls from the control room.
II.A.2.19 Add a motor operator. to valve MSS-017 and valve MSS-018 to provide isolation of Atmospheric Dump valves PV-20562A and !
PV-20571 A respectively. MSS-017 and l MSS-018 are to be re-tagged HV-20517 and {
HV-20518 respectively. Valve power shall l be Class 1 with manual open/close controls i from the control room. HV-20517 shall have power backed by GEA; HV-20518 by GEB. Note: ADY manual isolation valves MSS-019, MSS-021, MSS-020, MSS-022 are to :
remain closed during normal operation until motor operators can be added to them.
II.A.2.20 Modify MFW punp turbine steam valve ,
HV-20565 control to receive a priority i
close signal on AFW initiate from TIE cabinets H4EIA1 and H4EIB1.
II . A. 2. 21 In addition to control room indication required above, the following Class 1 indication and controls will be panel mounted in the control room:
l II . A. 2. 21.1 SG "A" low level, wide range I
level and pressure f rom EFIC channels A and B (f rom ;
- cabinets H4FWA, H4FWB).
II.A.2.21.2 SG "B" low level, wide range j level and pressure from EFIC i channels A and B (from cabinets H4FWA, H4FWB).
II.A.2.21.3 SG "A" AND SG "B" level selection back lighted pushbuttons plus auto selected level setpoint indication lenses.
II.A.2.21.4 AFW flow rate indication (Channel A & Channel B) for both SG "A" and SG "B". j 5415MAJ Page 12 Rev. 3 I hh
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A-5415 MAJOR NCIL Work Request _ 104415 l -
- Divaioline MOD II . A.2.21. 5 One shutdown bypass back
' lighted pushbutton for each EFIC channel.
II . A. 2. 21. 6 EFIC channel A and channel B l manual trip / reset pushbutton matrices. l II . A. 2. 21. 7 EFIC channel A and channel B l AFW control valve control reset switches.
II . A. 2. 21. 8 Open/close switches for HV-31826 and HV-31827 mounted with other AFW controls.
II.A.2.21.9 Condensate Storage Tank level ,
j l
i indication (A and B l Channels). (Not recuired for !
initial operation of EFIC.)
II.A.2.22 Control Room modifications required to implement the above changes include:
l II.A.2.22.1 Removal from HlRC the ICS hand / auto control stations i for FV-20527 and FV-20528. '
Add EFIC hand / auto controls for FV-20527, FV-20528, FV-20531 and FV-20532 to HISS.
l II.A.2.22.E Removal of AFW flow I indication f rom H2PS.
II.A.2.22.3 Removal of AFW control valve hand controllers (HC-20527 and HC-20528) from H2PS.
II.A.2.22.4 Removal of steam generator level indicator LI-20503B and LI-20504B f rom H2PS.
l II.A.2.22.5 Replacement of ICS, ADV hand / auto control station with EFIC ADV hand / auto control station on (HlRI).
II.A.2.22.6 Removal of ICS power f ailure ADV failure mode select switch (HS-20562C) from HlRI.
5415MAJ Page 13 Rev. 3 bD
A-5415 MAJOR NCr ' t'ork Reques9 104415
- ECN Discipline I&C MOD 001 Date 5-8S87
! II.A.2.22.7 Removal of Steam Line Failure Logic " Enable / Bypass" switches f rom H1SS.
II.A.2.22.8 Removal of ICS AFW control i
override switches (HS-20527 '
and HS-20528) f rom HISS.
II.A.2.22.9 Addition of open/close hand f switches for HV-20515, HV-20516 on HlRI.
II.A.2.22.10 Changing location of i open/close hand switches for !
AFW cross-tie valves HV-31826 i
and HV-31827 from H2PS to H1SS.
II. A.2.22.11 Install an extension panel on the end of panel HlSS to be called HlSS (E). This panel will contain all of the AFW controls. The icyout of this panel is shown in Figure VI.
II.A.2.22.12 Add motor operators to valves MSS-022, MSS-020, MSS-021 and ,
MSS-019 to provide isolation of Atmospheric Dump Valves PV-20562B, PV-20562C, PV-2051718 and PV-20571C respectively. Valve power shall be Class 1 with manual open/close controls from the control room. Not required for initial operation, see II . A. 2.19.
II.A.3. Changes which are part of Mod 1, but which are to be implemented at the next refueling following implementation of the above modifications.
II.A.3.1 Modify the NI/RPS Field Change Package FCP-3473 to include the Reactar Power vs.
MFW flow Anticipatory Reactor Trip into !
the RPS trip string. Modify the NI/RPS I Field Change Package FCP-3311 to delete the " Loss of Both Main Feedwater Pumps with Reactor Power greater than 20%" l Anticipatory Reactor Trip. Implement these changes in the NI/RPS.
5415MAJ Page 14 Rev. 3 ;
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A-5415 MAJOR NCF .,, Bork Reques?$104415 ECN w u
. I&C 001 Data 5-8-87
-Discipline MOD )
l II.A.3.2 Removal of existing H1SS console and.the i' new H1SS (E) extension and replacement with a new one of same cross section but j 24" longer. Console structure is Class 1 '
seismic. Console layout consolidates AFW controls, MFW controls, Condensate Controls, Turbine Controls and Generator Controls, as required by the Control Room Design Review. Console byout is shown on Specification N25.08 drawing sheets 1 thru 8,
II.A.3.3 Using operating data gathered during fuel Cycle 8, develop a procedure for setting and maintaining the EFIC MFW overfill level bistable and delay setpoints.
II.A.4. Changes of power sources to move the AFW components to the new TDI diesel generators (GE-A2 and GE-82) is to be complete prior to initial EFIC operation. This was decided upon after initial issue of this DBR.
Changes to reflect the move are based upon the following:
l II.A.4.1 Assumptions :
Motor driver for P-319 and I
II.A.4.1.1
' P-318 must be moved to new diesels.
1 P-318 to remain a "B" train II.A.4.1.2 component; P-319 an "A" train I l
component.
l II.A.4.1.3 AN flow, AFW pump pressures, i and CST levels would require l no changes (i.e., signal 1 conversion cabinets H4SCA and H4SCB are powered from S1 A2 i and S1B2; the same 120 VAC !
assured sources which power EFIC "A" and "B" i respectively. )
II.A.4.1.4 AFW should be " associated" with the new diesels (GE-A2 &
GE-B2) while HPI/LPI should be " associated" with old diescis (GEA & GEB).
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l A-5415 MAJOR NC"' Mork Requeso- 104415 ECN ~
~
I&C 001 Date 5-8-87 l Discipline MOD II.A.4.1.5 Heat tracing, IDADS, SPDS and '
Yard Lighting are not considered essential to AFW operability.
II.A.4.1.6 Interaction between GEA and GE-A2 is not considered although R.G.1.75 separation is not observed; similar for GEB and GE-B2.
II.A.4.2 Important Constraf nts:
II.A.4.2.1 Battery "A2" is required to load GE-A2; Battery "B2" is required to load GE-B2; Battery "A" is required to load GEA; Battery "B" is i j
l required to load GEB.
II.A.4.2.2 AFW must be available for loss of all AC power cases, I
" Station Blackout" (min. 2 l l
j hours). A single turbine l driven AFW pump is acceptable l for this case.
i II.A.4.2.3 Although ECIC channels A, B, f
' C and D are separated electrically, there are two )'
important points of commonality. First, for operation of the channels I longer than two hours, and concurrent loss of off site I oower, battery BA2 which ,
powers Channel A and battery l BC2 which powers, Channel C are both re-charged from i
' diesel GE-A2 while batteries BB2 and BD2 which power Channel B and D respectively are re-charged by diesel GE-B2.
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ECN A-5415 MAJOR NC! t5ork Reques' _ 104415 I&C 001 Date 5-8-87 Discipline MOD ,
Secondly, for Appendix "R" scenarios with worst case interaction assumptions for fires in the tank farm or Auxiliary Building, EFIC Channels A and C cr B and D i are assumed to be impacted.
Therefore, for certain Appendix "R" scenarios the AFV control valve arrangement effectively reverts to a two j channel arrangement. With !
such an arran* ment it is possible with assumed
" single" failure to assure feed or assure isolation but j not both.
II.A.4.3 For the AFW system the following power sources were agreed to.
II.A.4.3.1 Move controls and power sources for HV-20577 HV-20578 to the NSEB. These valve motor actuators should be ,
I changed to D.C. motors.
Valve HV-20577 will retain its control signal from EFIC Channel D but power will be from battery backed panel I SOD 2. Valve HV-20578 will retain its control signal from EFIC Channel C but will be powered from battery backed panel SOC 2.
II.A.4.3.2 Valves MV-31826 and HV-31827 will have their controls l
moved to the NSEB and will be powered from GE-B2 (S2B3) and GE-A2 (S2A3) respectively.
II.A.4.3.3 Valve HV-30801 will have its controls moved to the NSEB and will be powered by battery backed panel SOB 2.
5415MAJ Page 17 Rev. 3
NCP - Work Requestyl04415 A-5415 MAJOR ECN Q
001 Date 5-8-87 I&C Discipline MOD II.A.4.3.4 The motor driver for AFW pump P-318 will have its controls !
moved to the NSEB and will have controls powered f rom switchgear 54B2 and be powered from GE-B2.
II.A.4.3.5 The motor driver for AFW pump P-319 will have its controls moved to the NSEB and will have controls powered by switchgear S4A2 and be powered f rom GE-A2.
II.A.4.3.6 The relative physical placement of AFW isolation valves HV-20578 and HV-20582 will be re-configured f rom previous concepts such that FV-20528 and FV-20578 are in series and FV-20532 and HV-20582 are in series.
From II.A.4.2.3 this yields a priority " feed" mode and requires for Appendix "R" scenarios that either the exact routing of control and power cables will show that I there is not common mode fire damage to Channels B and D or I A and C, or that other operator action to stop and/or control flow are available (e.g. cycling of the AFW pump). A detailed review of cable routing will-be required to detennine the appropriate failure modes and/or required operator actions.
II.A.4.4 Other components associated with either MOD 001 or EFIC were assigned power sources as follows:
II.A.4.4.1 Isolation valves for ADV's and TBV's will be powered from the Bruce - GM diesels.
Power " Train" assignment matches the steam line.
Therefore, HV-20517 and HV-20521 will be powered from S2Al; HV-20518 and HV-20522 from S2B1. This same Page 18 Rev. 3 5415MAJ 7ky
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NC" Work Reques" 102415 A-5415 MAJOR ECN I&C 001 Date 5-8-87 i Discipline MOD reasoning applies to HV-20569 and HV-20596 the steam isolation valves to the AFW pump Turbine (K-308) which will remain on their current l source s.
I I
II.A.4.4.2 MFW isolation valves HV-20515 and HV-20516 will continue to be powered by GE-B2 (S2B3).
And MFW block valves HV-20529 and HV-20530 will have their controls moved to the NSEB and be powered from GE-A2 (S2A3).
II.A.4.4.3 Main Steam cross-tie HV-20565 is both a steam isolation valve and a valve necessary j to assure steam availability l to K-308. Since the valve is normally closed and closure is the " safe" position it was decided to leave the controis "as is" with power from GEB (52B1).
II.B. Desian Basis II.B.1. Design Basis for the AFW system (including MFW isoS ' ion following Steam Line break) is fundamentally based upon NUREG-080010.4.9, Standard Review Plan Auxiliary Feedwater System (PWR).
Specific exceptions to NUREG 0800 are: i II.B.l.1 The AFW system at Rancho Seco does not ,
normally operate (provide flow to the steam generator) during start-up, hot s'.andby and shutdown. The AFW system is an emergency back-up to the Main Feedwater System, or may be used at the control room operator's discretion. The AFW system will initiate and function in the fully automatic mode when required (see section 2.1.4.2 Actuation Requirement; System Description; Reference 28) if the pressure in both Steam Generators had been operating at 750 psig or greater. It shall be possible to initiate the APW System manually (in the fully manual or fully automatic mode) at any time that the Decay Heat Removal (DHR) system is not the principal core cooling system.
5415MAJ Page 19 Rev. 3
1 NCF " Work Reques- 104415 ECN A-541 GMAJOR
% e I&C 001 Date 5-8-87 Discipline MOD II.B.l.2 Plant cooldown from hot standby to the DHR cut-in temperature using only safety grade equipment controlled from the control room (NUREG 080010.4.9 1.18) assuming worst case single active f ailure is not a design basis for Rancho Seco. This is however a i design objective (as opposed to }
requirement) for the EFIC system and its l
controls in the control room. l II.B.1.3 AFW system unreliability as analyzed using methods and data presented in NUREG-0611 !
and NUREG-0635 may not meet the absolute l requirements of NUREG 0800 II.5.C. This !
is discussed in SMUD letter to NRC dated September 8,1981, " Auxiliary Feedwater System upgrade Reliability Analysis dated April 1981 (See I.8) and NRC's SER of EFIC dated Sept. 26,1986 (Ref. 53) . Using methods appropriate to the specific design of the " upgraded" AFW system at Rancho Seco, B&W concluded that unavailability of full auto initiation was 9 x 10-5 per f t demand. The unavailability per demand as l calculated for the NRC by Brookhaven National Labs was 7.6 x 10-4. The differences are discussed in section II.B.6 (page 33) of the SER (Ref. 53).
II.B.2. Additional Desion Bases for EFIC and EFIC Related ]
Chances per MOD 1 ;
t I
Section 2.0 System Requirements of the EFIC AFW System Description (Ref. 28) lists design bases for the AFW system.
l The EFIC AFW System Description is the most recent i' evolution of the documentation which forms the licensing base for the EFIC concept. The EFIC AFW System Description is a direct descendent of B&W document 15-1120580. Revision 00 of that document was the basis for the NRC's positive preliminary Safety Evaluation Report of the AFW Upgrade issued to the District by letter dated January 22, 1981.
l As the design of EFIC and related system upgrades were fleshed out, revision 01 of t5e AFW System Description (15-1120580-01) was sent to the NRC September 8,1981 (Ref. 25). The NRC subsequently '
issued on September 7,1982, on S.E.R. against that revision of the System Description. Following issuance of that S.E.R. there was some confusion within the NRC as to whether they had acted upon sufficient infomation.
5415MAJ Page 20 Rev. 3 g
NC" Work Reques" 104415 ECN A-5415 MAJOR w
I&C 001 Date 5-8-87 ,
Discipline MOD So, in a letter dated December 8,1982 (Ref. 7) the NRC requested additional EFIC and AFW information. l Subsequent letters from SMUD to the NRC (references 1 I and 2) supplied additional information and on April 7,1983 the NRC issued an SER covering this AFW upgrade, but noted three exceptions.
On April 28,1983 (Ref. 6) the District sent a revised AFW System Description to the NRC (15-1120850-03). That document is the last revision of the B&W System Description sent to the NRC.
On September 26, 1983 the NRC issued an SER which covered the EFIC and related changes to the AFW l
system. That SER stands as the last official i approval of EFIC (Ref. 53).
B&W revised document 15-1120850 one more time (Rev.4), however, the only substantial change to the document was the addition of Rancho Seco specific EFIC setpoints for S.G. low level initiate, etc. The I
EFIC AFW System Description, which is attached to and forms a part of this D.B.R., is a SMUD Nuclear Engineering revision of B&W decament 15-1120580-04. :
SMUD letters to the NRC dated January 17,1986 and f March 3,1986 (References 26 and 27) briefly describe
' the Mod 1 (EFIC) scope particularly for fuel cycle
- 8. The latter reference contains, for the NRC, a brief description of the substantive differences i between the last official system description sent to l i
them and the design as stated in the most recent EFIC AFW System Description. ,
I Significant pennanent changes to AFW upgrade design as compared to the status of design described in System Description Doc. 15 1120580-03:
AFW pump P-319 will be actuated by EFIC channel A. 1.ikewise AFW A) pump P-318 will be actuated by EFIC channel B using it's turbine driver.
B) The use of ime delay circuits in the initiate logic will be utilized to a.!nimize spurious actuations. See Figure 2.2-4.
C) The shutdown bypass permissive signal has been altered to allow bypass when either steam generator secondary pressure is below 725 psig. (See Figure 2.2-4). This simplifies operator action during a tube rupture scenario.
D) Position indication of manual valves in the AFW flow path is not to be provided since each is locked in its safety position during plant operation.
Page 21 Rev. 3 5415MAJ
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. .1 A-5415 MAJOR NCP Bork Request 1104415 ECN -
Discipline I&C MOD 001 Date 5-8-87 _
E) The required AFW flow capacity has been altered from 760 gpm to h 475 gpm.
II.B.3 Appendix R - Components used in various appendix "R" procedures are impacted by this modification, this ,
includes Atmospheric Dump Valves (ADV's), AFW control !
valves and AFW pumps. Also hand / auto stations to control ADV'S and AFW control valves are being added to the Appendix "R" shutdown panel to f acilitate plant control in the event of fire in the control room.
II.B.3.1 It shall be possible to electrically isolate any EFIC control circuit which passes through the control room such that after isolation has occurred no adverse EFIC control action can occur due to fire in the control room. No damage to the EFIC circuitry shall occur due to fire in ;
the control room. l II.B.3.2 Automatic initiation of AFW and/or automatic isolation of MFW is acceptable but not necessary to mitigate tne effects of a fire in the plant. Manual initiation of the AFW via EFIC is sufficient. l II.B.3.3 Controlled AFW flow and pressure control I
via the ADV's shall be possible for at least one steam generator for all Appendix :
"R" scenarios.
II.B.3.4. EFIC powered control parameters (S.G.
level, S.G. Pressure) shall be indicated at the place where the controlling EFIC hand / auto station is located. Indication shall be from the same EFIC channel as the controls.
II.B.3.5. Those portions of EFIC, its controls and l
indication which are used scenarios need to not miti (gate Appendix "R" for Appendix "R" reasons) be Class I, but must operate operate with or without the availability of off site power. Assured power sources including both battery backed electrical power and compressed air bottle back-up instrument air must be available for at least 2 (two) hours following loss of offsite power. After two hours, local manual control is permitted.
5415MAJ Page 22 Rev. 3 1
ECN A-5415 MAJOR NCP' Work Reques o 104415 l Discipline I&C MOD 001 Date 5-8-87 II.B.4 EQ Requirements - Some components in Mod 001 are subject to the EQ requirements of 10CFR50.49. The i specific components and requirements are identified )
I in the DBR's for each sub ECN.
II.B.5 ADV Controls and Isolation - The three reasons that l I
EFIC is required to control the ADV's are:
- To avoid "mid-scale f ailure" problems associated with loss of power to the ICS.
I To provide safety grade controls and components, i to assist in assuring ability to cooldown from hot ;
shutdown to the decay heat system cut-in l temperature.
To provide three independent turbine bypass I I
controls to preclude common mode failures associated with the N.I. Calibration error l problem; one for "A" steamline ADV's, one for "B" i steamline ADV's, and leave the TBV's under ICS control . j The last of these is the least obvious. It stems l from a Babcock & Wilcox preliminary safety concern l l
FSC 7-78 N.I. calibration error. The final report docesenting specific analyses for Rancho Seco i i
l which forms the basis for having no more than 28% l bypass is reference 60.
i The operating license for the Cycle 7 core limits the amount of " turbine bypass" to less than 28%
) bypass. That is, the combined valves wide open (VWO) flow of all operable turbine bypass valves (TBV's) and atmospheric dump valves ( ADV's) must be less than 28% of total main steam flow at 100%
power. This is currently accomplished by requiring closure of the manual isolation valves in series with at least four of the ten ADV's and TBV's . The basis for restriction is the need to limit inadvertent core over-power conditions due l
to Neutron Instrumentation errors from moderate frequency overcooling transients caused by a single control system f ailure. This is discussed in reference 60.
5415MAJ Page 23 Rev. 3
o Work Reques 104415 ECN A-5415 MAJOR NCr ' j 4
v I 001 Date 5-8-87 Discipline I&C MOD Unless the fuel operating license is ammended, this restriction on allowable ADV/TBV flow capability will cont nue even though the assumed basis will no longer moly. That is, with EFIC l
l channel A controlling t. Vee ADV's, EFIC channel B controlling three ADV's, and ICS controlling all j four TBV's no single control circuit or shared
{
control component can cause more than 28% bypass j flow. Therefore, although MOD 1 will implement controls to all six of the ADV's, the current restriction allowing use of only two will still apply for the durat1on of cycle 7.
Note also, that the companion requirement for motor operated valves in series with the ADV's and TBY's (sub-ECN A5415 AC and AD) doesn't impact this design bases. Those isolation valves are for isolation of a not closed ADV (or TBV) to prevent overcooling following reactor trips.
II.C. Scoce Scope of design criteria is covered in II A and II B above.
II.D. Eouipment Class and Power Requirements The classification of equipment and their power sources is ]
covered in the EFIC AFW System Description section 3. Seismic !
classification of APW piping is specifically covered in a SMUD l l
letter to the NRC dated January 14, 1983 (Ref. 2).
The design of EFIC and it's relationship to components it !
l interf ace with, assumes that an emergency diesel generator and !
it's associated emergency bus is independent of any other.
i.e. failure of a diesel generator and/or its bus will not cause f ailure of any other. Also, loss of a diesel generator l cannot cause loss of a battery powered bus for as long as the batteries are able to power the bus.
II.E. Testino II.E.1. Surveillance Testing for safety critical systems and components is covered by the Rancho Seco Technical Specifications as amended to include the Draft Tech ,
Specs, B&W document 05-0004 dated March 25, 1985 i (Ref. II).The draf t tech specs cover only the EFIC, l l
SFAS, and RPS.
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Mork Reques+'104415 ECN A-5415 MAJOR NC .'~
. .g MOD 001 Date 5-8-87 Discipline __I & C II.E.2. Start-Up Testing II.E.2.1. Insitu testing of'the EFIC circuitry is required to assure that the CMOS Devices have not altered since the system test was performed at the Vitro f actory in February 1984. Vitro Equipment Test Procedure TP-3801-4009 functionally tests each circuit and is available for our use. ,
I II.E.2.2. Test specifications for the RPS and SFAS changes (B&W Field Changes Packages FC-3473 and FC-3478 respectively) are included in the change packages. In addition, the Reactor Power vs. MFW flow ,
Anticipatory Reactor Trip (ART) will not l be_used to trip the reactor until it has j been tested for a fuel cycle under normal operating conditions. (See Section III C)
II.E.2.3. Test specifications for other specific components will be addressed by the ,
specific Sub-ECN design package. l l
II.E.2.4. A test specification for the entire i upgraded AFW system including EFIC, Main Feedwater Isolation and ADV control is l presented in B&W Document 62-1149372-00 (Ref. 10). The Test Specification was l 1
prepared prior to the start-up of the j EFIC system at Arkansas Nuclear One and '
Crystal River 3 and therefore could not t reference that operating experience. It ;
l is recommended that those portions.of the test spec requiring high decay heat rates not be perfomed if RCS and secondary system response has been demonstrated at other B&W operating plants. Rather, the adeauacy of equipment response should be verified using a test procedure ' adapted from TP-3801-4009 (Ref. 29).
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ECN A-541 SMAJOR NC" t$ork Reques" 104415 l-
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Disciplir:e I&C MOD 001 Date 5-8-87 III. Calculations and Design Information III.A. Design Features i
The design features of the EFIC AW upgrade are covered by section 3 of the System Description (Ref. 28). Additional specific information concerning the EFIC and T.I.E. can be l
obtained from the vendor drawings. A listing of the Vitro l (EFIC) and Consolidated Controls Co. (T.I.E.) vendor drawings is included as reference 9. Equipment instruction manuals are also available.
A study of the " human factors" associated with operation of l the EFIC is available; see reference 13.
III.B. Functional Description ,
l I
l A functional description of the EFIC AFW upgrade is found in f I
I the EFIC AFW System Description (REF. 28).
III.C. Design Calculation III.C l. AFW Flow - The minimum required AFW flow required even under the worst case single failure assumption l
which would limit AFW flow to the steam generators l is 475 gpm total flow to the SG's within 70 seconds of loss of Main Feedwater (LOMF). Reference 63 summarizes the calculation input and results for the design base case Loss of Main Feedwater with no loss of offsite power. j Previous correspondence with the NRC (References 1, 2, and 6) established the Loss of Main Feedwater as l the design base case and showed that a required AFW l flow rate of 76C gpm was supported by analysis (References 43 and 45). The NRC has specifically accepted that position via the AFW upgrade S.E.R.
(Ref. 53). The new analysis (Reference 63) which ,
shows that 475 gpm AFW flow will also fulfill tne cooling requirements for the design base case will be submitted to the NRC as part of the EFIC AFW l
upgrade Technical Specification Change Request 152.
As stated in the EFIC AFW System Description Section 2.1. the AFW flow to a single SG should not exceed 1800 gpm. This limit is affirmed by a recent B&W Study; Reference 64.
5415MAJ Page 26 Rev. 3
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NC" Bork Reques' 104415 q l ECN. A-S415 MAJOR I&C 001 Date_, 5-8-87 Discipline MOD III.C.2. Condensate Storaae Tank Capacity - The required AFW flow calculation cited aoove recognizes that not only decay heat, but also Reactor Coolant Pump (RCP) heat input must be considered for AFW cooling requirements. A calculation showing the effective cooli'ig capacity of the CST which takes this into consideration is shown in reference 44. This shows !
that at a minimum initial level approximately 10.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> of water are available to cooldown to the Decay Heat Removal cut-in temperature. l III.C.3. EFIC Setooints - There are several EFIC setpoints which are of interest due to their potential impact f on t.omal and emergency operating procedures. These include S.G. low level initiate, S.G. low pressure initiate, ADV pressure control setpoint, and AFW level control setpoints. The various setpoints (see Table 4.2-1 of the System Description) were I
calculated based on operating experience, transmitter error, special S.G. fluid condition i l
calculations, containment environment, etc. The calculations which are the basis for the setpoints i
are collected in one B&W calculation 32-1155738-00 l
dated 1/22/85 (Ref. 48). References 30 and 31 became the basis for environmental tcuperature range l input for level transmitter and liquid filled reference legs inside containment. Reference 39 documents the accuracy of the level transmitters to be used. Reference 46 documents the basis for the l "ECC Level Setpoint". Note that the level transmitter string accuracies assume that the reference legs are insulated and therefore never exceed 145'F; even during accident conditions in containment.
l l '
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. t Discipline I&C MOD 001 Date 5-8-87 III.C.4. Steam Generator Level Controls - The EFIC steam generator level controls nave the requirement to assure sufficient but-not too much cooling water flow. This requirement must be fulfilled with two redundant flow paths. EFIC employs for each S.G.
two independent control trains each utilizing the same but independently measured feedback parameters. This raises several control stability questions, particularly during natural circulation conditions in the RCS. These questions were investigated by B&W. Reference 40 establishes the preference for a " rate limited" level rise control and Reference 38 investigates control stability and the ability of the controls to act in the full automatic mode for et least 10 minutes for all expected decay heat scenarios without requiring operator action to keep pressurizer level within limits.
III.C.5. Main Feedwater Overfill (MFWOF) Overfilling the Steam Generator has been a concern for several years. However since the required action to mitigate overfill produces a LOMFW event, there has been reluctance to protect against it.
Additionally, there are with the OTSG design two distinctly different " overfill" problem regimes.
The one is excessive feedwater flow at high power levels. This regime has the potential to produce hydraulic instability in the SG's and to send wet steam to the first stage of HP turbine blades. The other regime could occur at low power levels and would literally fill the SG's with liquid. RCS overcooling and weight of water in the steam lines are concerns for this event. Reactor power excursions due to moderator temperature feedback are of interest but of no concern. i B&W investigations specifically aimed at proving l out the EFIC MFW overfill concept are presented in j reference 35, 36 and 37. Reference 36 is the confirmatory calculation showing that isolation of .
MFW within 15 to 30 seconds is sufficient to l prevent excessive moisture from carrying over into the steam lines. Reference 35 and 37 were investigations into more elaborate MFWOF detection schemes than that used by EFIC. Their so called
" variable overfill limits" were rejected as ineffectual or not cost effective.
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ECN A-5415 MAJOR NC^ Work Reques " 104415 Discipline faC M00 001 Date_ 5-8-87 The original EFIC concept included MFW and AFW overfill isolation logic. However that design utilized a common bistable in each EFIC channel to i
" decide" to isolate both MFW and AFW. Even though i the particular f ailure would have required four independent failures (or eight bistables to be
. grossly mis-calibrated by a single technician) the "conrnonality" aspect led to deletion of the AFW overfill portion of the designs; See also P55 of the NRC EFIC SER, Ref. 3.
Having no automatic protection for AFW overfill is justified since it is a slow developing transient which would allow time for operator intervention.
The operator will still be alerted to an overfill via the MFWOF circuits, and controls and indications are available to the operator to isolate AFW from the control room.
III.C.6. LOMFW Anticipatory Trip - As noted in several submittals to the NRC (e.g. References 6 and 24) {
l the District intends to install as its response to
! NUREG 0737 II.K.2.10 an Anticipatory Reactor Trip (ART) based on a comparison of reactor power and MFW flow. This is described as the Reactor Power vs. MFW Flow ART's, the Flux /MFW flow ART's, or the 0/MFW Flow ART's. The Trip is developed in the RPS in a comparitor module which compares measured reactor flux to total measured MFW flow.
Since MFW flow tends to be a fairly noisy signal, i I
there was initial concern that this scheme might lead to spurious trips of the reactor. Therefore,
" operability" evaluations were undertaken to collect data from Rancho Seco and other operating plants to assure that spurious trips would not be a
< problem. References 21 and 23 transmit B&W studies 51-1135242-01 and 51-1141558-00 respectively.
These studies show that spurious trips should not be expected. Reference 18, 19, 20 and 22 transmitted Rancho Seco operating data to B&W as a partial basis for the studies. >
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upon MFWP Turbine EHC pressure will continue.
However, the Flux /MFW flow trip may be used to tell l EFIC to start AFW, This is acceptable since based l
upon the considerable existing data we expect there to be no problem, and starting the AFW will not produce flow to the SG's as long as sufficient inventory actually exists.
III.C.7. AFW Pumo Runout - EFIC and the upgraded AFW system i
~
have provisi,Jn for automatically isolating AFW to a depressurized steam generator. However, various l probable scenarios can have one or both AFW pumps l
pumping for a short time to depressurized S.G.'s. J A study performed by Emergency Research &
Consultants Corp. (Report No. ERCO-693 dated February 16, 1984) shows that the Rancho Seco AFW pumps could be operated in the full " runout" condition for at least 30 minutes without destruction (Reference 12).
III.C.8. EFIC AFW Power Sources - The EFIC system initiates That is, either AFW via two 100% trains of AFW.
train is sufficient to supply the required AFW to both steam generators. The A channel of EFIC starts P-319 and controls flow to both SG's through FV-20527 and FV-20528. The B channel starts P-318 by opening valve HV-30801 and controls flow to both SG's through FV-20531 and "V-20532. Either channel is sufficient to assure sufficient AFW flow, but care must be taken to assure that the failure of a common electrical source will not prevent AFW from both trains from reaching at least one SG. Another EFIC function is to isolate AFW to a steam generator which has experienced a major steam line failure. This is accomplished using four channel logic which acts directly on the AFW isolation and centrol valves. As with the AFW initiation and control function, care must be taken to assure that l a comon electrical power source doesn't prevent required AFW isolation. Additionally, care must be taken that single electrical power f ailures comon to more than one piece of equipment cannot prevent flow or isolation when required.
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ECN A-5415 MAJOR NC^ Mork RequesO104415 Discipline I&C MOD 001 Date 5-8-87' This theme is addressed in a study (Ref. 25) which shows that with power and logic channelized per the AFW system description, single f ailure will neither prevent feed nor isolation of AFW flow. In mid-September 1986, a decision was made to shif t all of the AFW electrical loads to the new Transamerica De Laval diesel generators- (GEA2 and GEB2) prior to initial EFIC startup. The power source study was updated to reflect the new sources and found to be acceptable (Ref. 59).
III.C.9. Voorade AFW Reliability - There are several sources l of information concerning reliability analysis'for l the Rancho Seco AFW system. The sources which (
figure prominently in the licensing of the upgraded 1 AFW system are:
This was used in early evaluations of the AFW system, including NUREG 0667. It also formed the analytical basis for requiring auto loading l of P-319 on the emergency bus following LOOP. l
- A Rancho Seco specific AFW Reliability Analysis ,
performed by B&W (Ref. 33). This analysis was l sent to the NRC in fulfillment of NURG 0737 II.E.1.1. (Ref. 26). It assumed EFIC and an AFW configuration like that which we will have af ter completion of MOD 1. I
- A Rancho Seco specific AFW Reliability Analysis l was performed by Brookhaven National Labs under contract to the NRC. This Analysis forms the analytical basis for the EFIC S.E.R. issued in April 1983, and is discussed and compared in the SER (Ref. 3) to both the B&W prepare analysis (Ref. 26) and the requirements of the Standard Review Plan (Ref. 4).
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III.C.11. EFIC Shutdown Bypass - There are four conditions which can cause EFIC to auto initiate AFW and/or I isolate MFW which need to be manually bypassed for a normal plant shutdown condition. Bypassing a safety system on a system level requires a i coincident permissive signal (See IEEE-279). In the original EFIC hardware specification two of the conditions (low SG pressure, and loss of all 4 RCP's) were bypassed on a system basis, but required individual manual action locally at the four EFIC cabinets at different times during '
cooldown. The other two (low level in a SG, and high level in a SG) were to be handled procedurally by pulling breakers on the AFW pumps, etc. These shutdown bypassing methods were not acceptable to the District due to complexity and remote location of the EFIC cabinets.
A shutdown bypassing concept acceptable to B&W and the District was incorporated into the EFIC hardware. The concept uses a single bypass pennissive (pressure in the Steam Generator less than 725 psig), and can be enacted from the control room by pushbuttons on the HISS console. The correspondence which documents the design is found in Reference 14,15,16,17 and 49.
II.C.12 Sincle Failure Analysis - An analysis was performed by Vitro Ref erence 5N, in accordance with IEEE-279-1971 and IEEE-379-1977, that shows that the EFIC System meets the single f ailure criterion.
IV. FAILURE MODES Many of the operating modes of EFIC are discussed in detail in section 6.0 of the EFIC System Description (ref. 28). The plant casualty events discussed include the following: Loss of MFW (LMFW),
LMFW with loss of offsite AC power, LMFW with loss of onsite and offsite AC power, plant cooldown requiring AFW, turbine trip with and without bypass, main feedline break, main steamline break /AFW line break, small break LOCA, fire outside control room, fire in tne control room. In addition to these, various EFIC system failures are discussed in the following paragraphs.
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III.C ll. EFIC Shutdown Bypass - There are four conditions which can cause EFIC to auto initiate AFW and/or isolate MFW which need to be manually bypassed for a normal plant shutdown condition. Bypassing a ;
safety system on a system level requires a I coincident permissive signal (See IEEE-279). In !
the original EFIC hardware specification two of the i '
conditions (low SG pressure, and loss of all 4 RCP's) were bypassed on a system basis, but required individual manual action locally at the four EFIC cabinets at different times during h cooldown. The other two (low level in a SG, and l high level in a SG) were to be handled procedurally l; by pulling breakers on the AFW pumps, etc. These shutdown bypassing methods were not acceptable to the District due to complexity and remote location l of the EFIC cabinets.
A shutdown bypassing concept acceptable to B&W and '
the District was incorporated into the EFIC hardware. The concept uses a single bypass permissive (pressure in the Steam Generator less than 725 psig), and can be enacted from the control room by pushbuttons on the HlSS console. The correspondence which documents the design is found j
in Reference 14,15,16,17 and 49. t Sinale Failure Analysis _ -- An analysis was performed i II.C.12 by Vitro (Ref erence 55), in accordance with IEEE-279-1971 and IEEE-379-1977, that snows that .
the EFIC System meets the single f ailure criterion. l t
IV. FAILURE MODES i
Many of the operating modes of EFIC are discussed in detail in section 6.0 of the EFIC System Description (ref. 28). The plant casualty events discussed include the following: Loss of MFW (LMFW), i LMFW with loss of offsite AC power, LMFW with loss of onsite and offsite AC power, plant cooldown requiring AFW, turbine trip with and without bypass, main feedline break, main steamline break /AFW line breck, small break LOCA, fire outside control room, fire in the ;
control room. In addition to these, various EFIC system f ailures l are discussed in the following paragraphs. ,
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l IV.A. AFW Valve Failure I
Since each OTSG is supplied auxiliary feedwater from a line !
which is controlled by a parallel combination of series sets l l
of valves, there is no single failure which will prevent the l l isolation of or the feeding of the appropriate OTSG. Each of j l
the four valves is powered and controlled by a separate EFIC j Channel and power source. Consequently, a single channel !
failure will only cause the f ailure of one valve of the l parallel combinations, (i.e. one valve per OTSG). Each e
series set of valves is comprised of an isolation valve and a control valve. The control valves fail open on a loss of power or signal. The isolation valves, being motor operated, fail as-is. Since only one valve in the parallel combination i of the series set of valves fails, each OTSG can be either l fed or isolated. See also Section II.A.4.2.3 and II.A.4.3.6.
1 For f ailure modes of the individual valves see the DBR of the appropriate sub-ECN. l Note that the use of nomally open, fail open control valves with nomally closed isolation, valves, requires that at least one and sometimes two specific valves operate to close off excess flow for failures of moderate probability (e.g.
loss of a single battery set such as 50B2). Additionally, !
the isolation typically requiries operator recognition of the ;
! problem and subsequent action. Having the isolation valves
! nomally closed virtually requires battery backed, DC motor l
operators, since they must operate during the loss of "all l
AC" power case. If they were AC powered, a potential common l
mode failure is also present; i.e. failure of an "A" or "B" i battery would fail open the associated control vaives and loading of the associated diesel generator bus would also be prevented. Thus, the isolation valve might not be operable off of the diesel backed AC bus. All of the above withstanding, the proposed design is, none the less, very acceptable.
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c ECH A-5415 MAJOR NCT ' Mork Reques [104415 j Discipline I&C MOD 001 Date 5-8-87 IV.B. Failure of Fiberoptic Cables Between Channels The fiberoptic communication between EFIC channels is designed such that a single failure (such as a loss of all fiberoptic cables going into one EFIC cc5inet) shall not result in a failure of EFIC functions to actuate when needed. A single event, however, can cause an inadvertent actuation of either AFW initiation or MFW Isolation if the event affects more than one channel of initiation logic.
Initiation of AFW is of little consequence because it will l only supply low and they water to the steam need water. Isole ion !. enerators of MFW isif more the levels are serious and can lead to a plant trip, but this condition is 1 acceptable because AFW is available to cool the plant.
To meet this criteria interchannel fiberoptic cables do not require the same kind of separation that would be required of electrical cables. The difference is that the cables i entering a comon EFIC cabinet do not require separation from each other even though they belong to different ( A, B, C and D) safety channels. There are two reasons why this is so.
The first reason is that fiberoptic cables, unlike electrical cables, cannot propagate energy along the cable in large enough quantity to damage adjacent cables. Consider a cable running between the A and the B cabinets. A disturbance to the cable in Cabinet A can in no way damage an adjacent cable .
in Cabinet B. {
The other reason why the fiberoptic cables that enter a comon EFIC cabinet do not require separation is that the communication system is designed so that a f ailure of any cable can only cause trat signal to revert to an actuated state. In all cases this is the safe state which is shown in the following list of fiberoptic cable types:
l
- 1. Test Results l These cables are used to indicate at the other three l channels that a test is in progress on eithe.r A or B channel. The purpose of this indication is to warn technician / operators at the EFIC cabinets that testing is in progress. A failure of these cables will cause the test confirm (i.e., test in progress) light to turn on. This is the safe condition.
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- 2. Channel Bypass These cables transmit infonnation used to prevent more than one channel of EFIC being placed in maintenance l' bypass and to prevent other channels of EFIC being placed in maintenance bypass when an RPS channel is in bypass. A failure of these cables will both prevent 1
placing of channel in maintenance bypass and will take l out of maintenance bypass any channel that was already in bypass. The latter of these can cause a half trip of the EFW initiation and/or the Generator A and/or B MFW solation if work in another EFIC cabinet were in progress.
- 3. Vector Enable and Control Enable These cables are used to " enable" or start the vector i and control modules when EFW initiation occurs, and l allows automatic level control to begin. When the ,
cables are damaged the associate control and/or vector j modules are enabled. This is the safe condition since these modules are dormant during normal plant operations i only to decrease valve stroking.
- 4. Trip Inputs These cables transmit the outputs of the initiate l modules from the four channels to the trip modules in l Channels A and B to give the four channel initiation of trips. A failure in these cables can cause a half or a '
full trip of the EFW initiation and/or the Generator A and/or B MFW Isolation.
IE Information Notice 86-15 addressed the f ailure of some fiberoptic The cables duefrom memo to Radio Frequency Daniels to Lewis (Reference Interference.
- 56) explains why this should not adversely affect the EFIC fiberoptic cables and states that EFIC will be tested for this problem during start-up testing.
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ECN A-5415 MAJOR NCP " Work RequesQ104415 w e 5-8-87 Discipline I&C MOD 001 Date IV.C. Failure of RPS Inputs to EFIC Each channel of EFIC receives an actuation signal from the corresponding channel of RPS for the condition when both MFW pumps tripped at greater than 20 percent reactor power. The function of this signal is to initiate A7W.
Each channel also receives four Reactor Coolant Pump (RCP) ,
I trip signals from the corresponding channel of RPS. when all four RCP's have tripped, EFIC initiates AFW and the l s
channels A and B control modules raises their steam generator level setpoints to a level appropriate for {
natural circulation. In both of these cases, EFIC looks at the inputs as four channel and actuates based on one out of l two taken twice logic. Because of this, any single failure i of the inputs to one EFIC channel will not prevent l actuation of EFIC functions nor will it, by itself, cause !
1 inadvertent actuation.
l Each channel of EFIC also receives a channel bypass signal from the corresponding channel of RPS. The function of !
this signal is to prevent other channels of EFIC from being put into bypass when a channel of RPS is in bypass. A failure of this signal to actuate could allow one channel of EFIC to be put into bypass while a different channel of RPS was in bypass. In this condition it is possible to have two channels of RPS giving the signals for an EFIC initiation with both being bypassed. This does not prevent EFIC initiation, though, because there are two other channels of RPS that can initiate EFIC. Also, this event is extremely unlikely because the bypass of both RPS and EFIC channels will be under strict administrative control.
A failure of the channel bypass causing bypass actuation will simply prevent other channels of EFIC from being I placed in bypass or if any channel was in bypass it will ,
take it out of bypass. The latter of these can cause a !
half trip of AFW initiation or a half trip of the generator i A or B MFW Isolation. Also if the operator persisted in testing the bypassed RPS channel with the EFIC half trip condition and the corresponding EFIC channel not bypassed, j
! a full EFIC AFW initiation could occur. ;
The failure modes of the RPS inputs to EFIC are listed i below:
l Loss of Power - A loss of power in one channel of RPS 1.
will force the MFW pumps tripped and the RCP's tripped inputs to the actuated state and will force the channel bypass to the not bypassed state. A loss of ;
i the EFIC power used to sense the contacts in RPS will I cause the MFW Pump Trip to appear actuated and the channel bypass to appear bypassed but will have no affect on the RCP's tripped signals.
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Loss of Signal - a loss of signal will cause the MFW l 2.
pumps tripped and the RCP's tripped signals to appear actuated. A loss of signal will cause the channel bypass to appear to be in the bypassed state. ;
1 l
IV.D. Failure of SFAS Inout to EFIC The SFAS inputs to EFIC are designed so that a single failure will not stop EFIC from initiating AFW when SFAS :
actuates. There are channel A and channel B initiate {
signals sent to EFIC from SFAS, two signals per channel, each delivering a half trip to the AFW trip module. Either channel will initiate EFIC if both of its signals are :
actuated (i.e. two out of two taken once). In each channel J of SFAS there are two unit modules that supply the inputs to the corresponding channel of EFIC. These inputs are ;
open contact to trip EFIC and energize to open the contacts '
in SFAS.
! The following paragraphs summarize the failure modes:
- 1. Loss of Power -
A loss of power in a SFAS channel will prevent that channel from initiating the corresponding channel of EFIC but will have no affect on the other channel. A loss of power in an EFIC channel will prevent that channel of EFIC from initiating.
- 2. Sional Failure -
A loss of the closed contact signal integrity in one input to EFIC will cause a half trip of EFIC and a loss of both signals in one channel will cause a full trip. Similarly, a withdrawal of a unit module from SFAS will cause a half trip in its corresponding input to EFIC.
Since the SFAS signal is an energize to actuate a failure of an SFAS module to actuate will result in a f ailure of receiving the half trip input in EFIC.
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Discipline I&C MOD 001 Date 5-8-87 IV.E. Failure of EFIC Trip Interf ace Ecuipment EFIC actuates various components through the trip outouts of the train A and B Trip Interf ace Equipment (TIE) cabinets. These components actuate in response to an AFW Initiation or a steam generator A or B MFW Isolation. The outputs of train A are redundant to train B; therefore, a single event will not cause the failure of a required actuation. A loss of power to the TIE cannot prevent availability of the lE output in that train. However, loss of power to the 1E to non-lE TIE will prevent output of the non-lE circuit but cannot affect the lE portion of the signal. A loss of signal between the TIE and EFIC or between the TIE and a device will prevent actuation of the device.
IV.F. Power Sources Failures for EFIC and EFIC Related Hardware As addressed in Section III.C.8. and in Reference 25 and 59, a single failure of an electrical power source will not prevent controlled feeding of AFW to either steam generator nor prevent isolation of AFJ to a steam generator.
Discussed here are some specific f ailures and their effects. All of these f ailures assume concurrent loss of offsite power.
IV.F.1 Failure of Diesel Generator GEA or GEE l
No AFW components are powered from these diesel i i
l generators. However, mainsteam system branch isolation valves are. Without GEB the normally closed HV-20565 would fail in its last position. j If closed, its EFIC function would be correct. If I open, and a major steam leak were occurring, both !
main steam lines would de-pressurize. In this !
event, P-318 would not function using the turbine !
driver. EFIC would feed both SG's. To avoid I overcooling, operator action would be required i either to close HV-20560 or to regulate AFJ flow !
manually.
1 IV.F.2 Failure of Diesel Generator GE A2 Without GEA2 power the APW pump P-319 would not operate. P-318 is sufficient for all cooling requirements and would be available in either its turbine or motor driven form.
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.3 Mork Reques? ' 1 04415 ECN A-5415 MAJOR l %. w I&C 001 Date 5-8-87 Discipline MOD Without GEA2 power MFW block valves HV-20529 and HV-20530 would not function. The EFIC MFW isolation function would still be assured by l
HV-20515 and HV-20516.
The above scenarios hold for a minimum of two hours.
IV.F.3. Failure of Diesel Generator GEB2 i
Without GEB2 the motor driver for P-318 will not be available. P-318 might still be functional on its turbine driver, and P-319 would still be functional.
Without GEB2, HV-20515 and HV-20516 would f ail in i
their last position. However, without offsite power, the condensate pumps would probably fail and flow through these valves will not occur. In any case, isolation of MFW would still occur via the MW control & block valves.
IV.F.4. Failure of EFIC and AFW indication in the Control Room.
Power for control circuits and for backlighting of pushbuttons which control EFIC comes from the EFIC channel affected e.g., if power to EFIC Channel i "A" is lost, the "A" channel EFIC control circuits on H155 will go dark and controls will be non-functional.
i The Class I analog indication on HISS requires two inputs to be functional; signal and power. If the 1 I
signal is lost, the display will go "off scale low". That is, the digital readout will be at it's lowest possible value, and the bargraph will flash a single LED in the lowest position. If the 120 VAC power is lost the indicator will go dark.
Power to the Channel "A" indicators is from the ,
same battery backed inverted power which powers EFIC Channel "A". P9wer to che Channel "B" indicators is from the same battery backed inverted power which powers EFIC Channel "B".
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Discipline _ I & C MOD 001 Date 5-8-87 Since all Class I indications except AFW pump l discharge pressure have redur. dant indicators of a l
different channel, the only process indication i
! lost on loss of a single power source would be ane of the pump discharge pressures. Control lights to the back lighted pushbuttons and the ammeter would be back-up indication showing pump operation.
IV.G. EFIC Control Failure l
The EFIC has six points of process control; two AFW flow .
l control and one main steam bleed off control per steam l generator. These six points are controlled by process ,
l control circuits within the A and B EFIC channels which send signals to the modulating control valves on the AFW l and Main Steam Systems. The function, logic, and control setpoints are discussed at length in the EFIC Auxiliary .
Feedwater System Description. l The f ailure of any process control, by its nature, will cause the process variable to move away from its desired l value. Failure of EFIC controls would cause the controlled variable (s) to move away from the desired value(s) causing l process changes which ultimately shift the point cf control. Preciseness, responsiveness, and stability of control are kinds of control f ailures. They are addressed in Sections III.C.3 and III.C.4. What we are talking about here is grass control failure which will cause the swif test shift in control point (i.e., what happens if a single event causes valve (s) to fail open or closed).
It should be noted that for the failures below, the rate of change of RCS and Secondary System parameters is not different than would be expected for similar control f ailures to the existing AFW and ADV controls.
IV.G.1 Atmospheric Dump Valve Fails Closed If not controlled by Turbine Bypass Valves main steam pressure would rise in the worst case and be controlled by the main steam relief valves. In the event the other steam generator was available, and has pressure control, RCS cooling would proceed through it and steam pressure in the impacted generator would follow saturation pressure consistent with RCS hot leg temperature.
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Discipline I&C MOD 001 Date 5-8-87 IV.G.2 Atmospheric Dump Valve f ails open l
The energy release would cause main steam pressure to decrease with a resulting decrease in S.G. secondary temperature. The RCS would in turn decrease in temperature. Operator action to isolate the open ADV(s) using the motor operated ADY isolation valves is the best response. However if S.G. pressure drops below 600 psig, EFIC will isolate MFW and AFW to the affected generator.
IV.G.3 AFW Valve Fails Closed ;
If an AFW control valve f ails closed, the process control point would shift rapidly to the parallel control valve.
IV.G 4 AFW Valve Fails Open The energy required to heat the cold AFW to saturation will cause a temperatun v i subsequent pressure decrease in the steam gewator. Operator action to isolate the open AFW valve using the series aligned motor operated isolation valve is the best operator response. Actual valve position indication is available to identify the errant valve If only one S.G. is impacted, the EFIC will l
automatically isolate AFW to that S.G. if pressure t drops below 600 psig. In the event that the excess AFW develops to an overfill condition, the MFW overfill protection and annunciation would alert t1e operator to the need to isolate the errant valve.
Note, however, that for initial operation of EFIC the MFW overfill setpoint will be at its uppennost setpoint in order to avoid spurious MFW closure.
IV.G.5 Single EFIC Control Failures The four bounding EFIC control failures are: loss of power to EFIC "A" or "B" channel, loss of a control module within EFIC "A" or "B" Channel, failure of a pressure c? level sensing circuit, wacko signal to a single device. A single tailure cannot simultaneously cause f ailure of control signals from both Channel "A" and Channel "B", and control f ailures for either channel would be similar. Therefore, only f ailures of Channel "A" will be discussed below.
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NCT Bork Reques9 104415 ECN- A-5415 MAJOR Discipline I&C MOD 001 __ Date 5-8-87 Loss of power to Channel "A" would cause the ADV(s) on one main steamline to f ail ;losed, and one AFW control valve to each S.G. to f ail open. During normal plant i operation no change in operation would result. If AFW has been initiated, the ADV closure would play a minor roll initially as cooling from excess AN flow would eventually dominate secondary pressure.. Manual '
closure of the series AFW isolation valves is required. Following re-pressurization, the failure of ,
the ADV(s) will become apparent and the course of action is as described in IV.G.l.
Loss of one of the two control modules within EFIC Channel "A" will cause either a control valve to the "B" 5.G. to fail open (see IV.G.4.) or a control valve and the ADV (s) of the "A" S.G. to f ail open and i closed respectively. This latter failure becomes a subset of loss of channel power.
Failure of a pressure sensor signal, though possible i in either direction, would be expected to f ail low.
This would cause the ADV(s) on one S.G. to fail closed and one AFW valve on the same S.G. to f ail closed (due to F.0.G.G. logic). Manual control of both valves, through EFIC, would still be possible. l.
Failure of a low range level sensor, though possible in either direction, would be expected to f ail low.
If it failed low, and AFW has been initiated, one AFW l control valve would fail open (see IV, G.4). If it l f ailed high one AFW control valve would f ail closed (see IV.G.3).
Failure of a wide range level sensor, though possible in either direction, would be expected to fail low.
This would lead to like scenarios for a failed low level sensor, but only if all RCP's were not running.
A failed signal to a single controlled component could cause a valve to open or close. Those events are described in IV.G.1 to IV.G.4. However, due to the nature of the 4-20ma control circuits used, f ailures which produce 4 ma or less are the expected failure modes. Therefore, the expected f ail state for a single component would be closed for an ADV(s) or open for an AFW control valve.
5415MAJ Page 43 Rev. 3 l
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ECN A-5415 MAJOR NCP ^ Work Request '104415 ;
i Discipline I&C MOD 001 Date 5-8-87 )
This control f ailure discussion assumes less of only l
one sensor or loss of power to all sensors in one channel. EFIC sensors may share process sensing lines with other EFIC channel sensors or other system ,
sensors depending upon specific sensor installation {
details. If more than one EFIC sensing parameter can l
l be effected by a single sensing line f ailure, those failures must be analyzed as a part of the sub-ECN, and the acceptability of installation detail judged therein. See sub-ECN's 5415A, 5415B, and 5415C. The r 1 relationship of shared sensing lines to IEEE-279 is /
i discussed in Ref. 61.
VI. __oecial S Operating Requirements i
Operating Description of EFIC Controlled Devices VI.A.
f VI.A.l. EFIC indicators - EFIC control room indicators display a comprehensive cet of infomation on the status and condition of the steam generators and the Auxiliary Feedwater System. During the following discussion of these, refer to Figure VI and Table VI for panel HlSS.
VI.A.l.l. For both steam generators A and B there are redundant (c.hannels A&B) meter indications of low range level (items 2&3 and 7&B), high range level (ite:ns 4&5 and 9&l0), pressure (items 27&28 and 32&33) and AFW flow to the steam generators (items 29&30 and 34&35).
VI.A.l.2. The Hand / Auto (H/A) stations for the four flow control valves, FV-20527,28,31 and 32, each contain a meter that indicates the position demand signal for its associated valve (items 35,87,89 and 91). Also actual position indications for each valve (items 84,86,88 and
- 90) are located directly above the associated H/A station.
VI.A.l.3. The two H/A stations for ADV control (located on HlRI not shown on Figure VI) contain a meter that indicates the position demand for the ADV's.
Actual position indications for these valves are not a part of MOD 1.
VI.A.l.4. For the AFW pumps there are meter indications of discharge pressure for each pump (items 119 &
124). Also there is a digital readout of the AFW test line flow and a meter indication of the flow valve's actual position (items 121 and 148).
5415MAJ Page 44 Rev. 3
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ECN A-5415 MAJOR NCF
- Work Request 3104415 Discipline I&C MOD 001 Date 5-8-87 l VI. A.l.5. The " Remote / Manual / Reset" pushbutton matrices which are mounted on the control room consoles (see items 6 and 31 of figure VI of section VI.A.) provide channelized indication of automatic actuation of EFIC functions. They also provide capability of operator manual actuation of some EFIC functions. To assure that manual r action at these two matrices could not cause all feedwater to be inadvertently isolated, nor that i an overfill situation could be inadvertently caused, a study was perfomed. It looked at all possible manual actions at the matrices, without I regard to reason for the action, and combined those actions with all automatic EFIC functions which might affect or be affected by that '
action. The results show that following EFIC actuation no action or combinations of actions at the matrices will prevent all feedwater from reaching the steam generator. Also no overfill can be similarly automatically or manually commanded.
It is theoretically possible for an operator to inhibit automatic actuation of AFW or MFW isolation. This reonires simultaneously pressing at least two buttor shich are spacially separated by at la . eight inches. This
" correct" combina, 1 of buttons must be depressed prior tt 'ceipt of a valid actuation and held continuously in order to inhibit ,
l actuation. It is also possible for the operator to place the AFW initiate in manual after AFW initiation. This would not prevent AFW initiation, but it would prevent subsequent " feed only good generator" logic from isolating AFW to a depressurized Steam Generator. This selection of the manual mode is indicated at the matrix and does not prevent the operator from manually isolating AFW to the affected generator. Any manual bypass or manual inhibit of an i.nitiate can be immediately reversed by operator selection of the actuation mode.
VI. A.l.6. In addition to analog indications, backlighted pushbuttons indicate status of EFIC initiation / manual operation, channel bypass, control enable and the steam generator level setpoints selected. Also backlighted pushbuttons indicate the status or position of the AFW pumps, isolation valves and crosstie valves. ,
5415MAJ Page 45 Rev. 3
Mork Request ~104415 'l ECN A-5415 MAJOR NCF .' l
% O I&C 001 Date 5-8-87 Discipline MOD VI.A.2. AFW control without auto Initiation of EFIC - Without l
auto initiation of EFIC all of the AFW controls can -l be directly operated manually.
l VL A .2.1. AFW pumps can be started or stopped manually (items 117,118 and 123). Also the AFW test flow valve can be manually t
operated (item 120) to increase or decrease test flow to the condenser. ,
VI.A.2.2. AFW flow to the. steam generators can be ;
started manually by starting an AFW pump, opening the isolation valves (item 56, 57, !
62 and 63), placing the H/A stations for ,
1 the flow control valves (item 85, 87, 89 and 91) in manual and running the valves ,
l I
open to obtain the desired flow..
VI.A.2.3. AFW flow to the steam generators can also be obtained by manually initiating EFIC channels A and/or B (items 6 and 31).
This causes starting of the AFW pumps, opening of isolation valves and initiation of automatic level control in the steam generators. In this state an operator can place the control valve H/A's in manual if l
desired to manually regulate the AFW flow to the steam generators.
VI.A.3 AFW control with Auto Initiation of EFIC - With an automatic initiation of EFIC the AFW and colated controls will be automatically positioned to supply AFW regardless of their manual position at the time VI.A.3.1. When EFIC initiates, the following equipment is automatically positioned with override of their manual controls: AFW pumps start, AFW isolation valves open, AFW test valve closes, Main Steam cross tie valve, HV-20565, closes. In order for these to be manually controlled, except the AFW isolation valves, EFIC must first be placed in manual or if the EFIC initiating signals have cleared then EFIC must be reset (items 6 and 31).
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NCF Mark Reques9 04415 ECN A-5415 MAJOR I&C 001 Date, 5-8-87
! Dis:ipline , MOD VI.A.3.1.1 The AFW isolation valves can be manually controlled while EFIC is initiated by first pressing the override button (combined with the open and
' close button, items 56, 57, l 62, and 63) and then pressing
' the open or close button to position the valve. When EFIC is reset or placed in manual the override automatically resets.
VI.A.3.2 Wnen EFIC initiates AFW, the AFW flow control valves begin to automatically control the level in the steam generators. At any time H/A stations for these valves can be put in manual and the valves manually positioned. When EFIC is placed in manual or reset these valves continue to automatically control steam generator level until the control enable switches are reset (items 59 and 61).
VI.A.3.3. Vector logic (Feed only good generator) i can cause isolation of AFW to either, but not both, steam generators by closing the appropriate isolation valves. These valves then can be manually opened if
- desired as described in Section VI. A.3.1.1.
VI.A.? i.FIC isolation of the Main Feedwater (MFW) - The MFW flow can be shut off to the steam generators by EFIC, either automatically or manually.
VI.A.4.1 The MFW isolation valves can be controlled manually to isolate or allow MFW flow to the steam generators. These controls are i overridden by the actuation of the EFIC Main Feed Water Isolation (MFWI) for either steam generator which causes the valves for the operator to close. MFWI can also be manually initiated (item 6 and
- 31) for either steam generator causing an isolation of MFW to that generator, Page 47 Rev. 3 5415MAJ I
1 l-A-5415 MAJOR NCF dark Reques' 104415 ECN _
I&C 001 Date 5-8-87 Discipline MOD l
VI.A.4.2. An actuation of MFWI causes the MFW t
! isolation valves to close, as stated above, and also overrides the ICS control of the MFW flow control valves causing the i valves to shut. These valves cannot be l cperated in manual until MFWI is placed in manual or reset (item 6 and 31). When i l
MFWI is placed in manual or reset the isolation valves will remain closed until manually opened. The MFW flew valves will i revert back to ICS control. l VI.A.4.3. When Main Steam Line Isolation (MSLI) is actuated its only function is to actuate the same devices as MFWI. The same functions of manual and reset will apply to MSLI as are described above for MFWI.
1 EFIC Control of Atmospheric Dump Valves ( ADV's) - l VI.A.4. '
Automatic control of the ADV's is always active in EFIC regardless of whether EFIC is initiated or not.
The ADV's can be placed in manual control at any time l from the H/A stations located on panel HlRI and l l
manually positioned. 1 i
VII. VERIFICATION CRITERIA:_
See VIII. A below.
VIII. COMMENTS:
VIII.A. Desfon Verification l
The functional design of the Emergency Feedwater Initiation and Control System was developed by Babcock &
Wilcox. As a part of the design process, B&W included a formal independent verification of EFIC and its relationship to the Rancho Seco upgraded AFW system. At B&W the independent verification is performed and documented by a Design Review Board. The members of that board are selected based upon their technical background, their germain experience and their lack of prior involvement in the task. The positive findings of the Design Review Board are documented in references 8 and 62.
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I&C 001 Date 5-8-87 Discipline MOD I
l VIII.B. Differences Between the Rancho Seco and SR-3, ANO-1 EFIC's l
Though known by several different names, all B&W Nuclear l
i Plants have Emergency Feedwater Initiation and Control Systems which are independent from the ICS. The form and features of these systems differ as required for site specific reasons. Three of the utilities operating B&W plants have system designs of their own or an A/E's design (Toledo Edison, GPU Nuclear, and Duke Power). The B&W late model (205 FA) plants have systems designed into the safety plant (grade plant protection systras delivered with theSupply The remaining three operating B&W 177 FA plants purchased l
the "EFIC" design from B&W (Crystal River-3, Arkansas l Nucloar One, and Rancho Seco).
Each of the three EFIC plants uses the same basic concept. Hardware for the three plants was purchased under a generic specification from the Vitro Corpor; tion. l However, some differences in hardware and its application
! do exist. The specific differences between the EFIC as it will be utilized at Rancho Seco (RS) and the EFIC l
installation at one or both of the other EFIC plants are listed below:
B.1. R.S. uses a single remote shutdown bypassing feature which will allow bypassing of EFIC initiation of the following: low SG level, low SG pressure, high-high SG level loss of all 4 RCP's. l This is only possible if SG pressure is less than l 725 psig.
ANO bypasses the low S.G. pressure and loss of all 4 RCP's locally (individually) at the EFIC cabinets. They don't " bypass" the low and high-high initiates. They prevent operation by pulling the trip breakers located in EFIC cabinets A and B.
CR-3 has a remote shutdown bypass for the icw S.G.
pressure only. Bypassing of the loss of all 4 RCP's is done locally at the cabinets. Bypassing of low S.G. level and high-high S.G. level are not provided, but (like ANO) are blocked by pulling breakers in the EFIC A&B cAinets.
Page 49 Rev. 3 5415MAJ 9
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A-5415 MAJOR NC F Work Reques*^ 104415 ECN
- w. .
Discipline I&C MOD 001 _ Date 5-8-87 l B.2. R.S. utilizes a shutdown bypass permissive such i
that shutdown bypassing is possible if either S.G.
cressure goes below and stays below 725 psig. ANO i
' will use a similar permissive for bypassing their low S.G. pressure initiate. CR-3 uses S.G.
pressure less than 725 psig in both S.G.'s.
CR-3 and ANO use a shutdown bypass permissive for loss of all four (4) RCP's based on reactor power being less than 10%.
B.3. R.S.'s EFIC uses a latch-in feature for the control enable circuits such that placing the EFIC Trip circuits in manual will not drop out the automatic level controls. This simplifies the operating procedures by not requiring manual control of AFW valves prior to placing EFIC in manual. Conversely it still allows the operator to take manual control of the control valves at anytime. CR-3 and ANO do not at this time have this latch-in feature.
B.4. The EFIC A & B channels have control signals for the AFV centrol valves emerging. from both their level control and their Vector (F.0.G.G.) logics.
l RS's EFIC prioritizes these signals internal to EFIC so that only one set cf control signals (from one power source) is necessary to convey all EFIC information to the valve controller. CR-3 and ANO require additional relay logic external to EFIC to perform the same function.
B . 5. The R.S. EFIC has provision for altering the ADV opening setpoint from the control room. CR-3 and ANO do not have this designed into their EFIC.
This feature will not be used at R.S.
B.6. The low range S.G. level at R.S. is between 6" and 156" above the lower tube sheet (TS) with the upper tap extending thru the downcomer annulus to sample pressure in the tube bundle. The high or wide range taps extend between 6" above the lower TS to 6" below the upper TS (6" to 613" above the lower TS). No composite full range is necessary.
5415MAJ Page 50 Rev. 3 6
NCP - Bork Request- 104415
ECN A-5415 MAJOR Discipline f&C MOD" 001 Date 5-8 i87 i At ANO the low range S.G. level is between 6" and j
156" above the lower TS with 7 of the 8 upper taps j
sampling downcomer pressure and the eighth >
extending through the downcomer into the tube bundle. The high range S.G. level extends between 102" and 500" above the lower TS with lower tap measuring downcomer pressure, and upper tap l j
measuring tube bundle pressure. A composite full j range level ulitilized by the control module is generated with signal conditioning and switching ;
l logic. j 1
CR-3 uses low range S.G. level taps at '6" and 277" i
above the lower TS. The upper tap samples downcomer pressure. The low range span is 150" e
I between 6" and 156" above the lower TS. The high range level taps are coincident with the operate !
range level taps at 102" and 384" above the lower T.S. A composite full range signal is utilized by ;
l the control module.
ANO Lses separate S.G. sensing taps for each of i it's 16 EFIC level transmitters whereas ANO and l R<S. share some taps. For the R.S. Specifac tap :
I scheme see sub-ECN 5415B.
l I
. B.7. R.S. will be using Gould type PD 3200 level transmitters. ANO and CR-3 use Rosemount l transmitters B . 8. All three EFIC's have relay switching internal to the cabinets, available to isolate and switch valve i i
control commands to either the main control room or j an alternate shutdown panel. CR-3 and ANO do not use the switching capability. At R.S. the switching is used to switch and isolate EFIC i' hand / auto control from the Control Room to the shutdowr panel for fires in the Control Room.
Also, the " manual / reset", bypass, and Channel DC I power circuits to EF C from the Control Room will be isolatable for the same fire scenario.
i B.9. The SFAS signals which comand EFIC to start AFW originate in two separate unit modules per SFAS actuation channel. This prevents f ailure of a 3 single SFAS module from spuriously initiating AFW. I 3
CR-3 and ANO designs use only one unit control module per SFAS actuation channel.
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A-5415 MAJOR NCP~- Work Request- 104415 ECN Discipline I&C M05 001 Date- 5-8'87 l
B.10. CR-3 and ANO use EFIC to command closure of Main Steam Isolation Valves. This function is available i
in the R.S. EFIC but is not used.
B.11. The EFIC cabinets at R.S. are located in four (4) separate rooms in the- NSEB. ANO has the four (4) cabinets adjacent to each other in the control room. CR-3 has the cabinets located in four (4) i rooms in the building which houses the control room.
B.12. At R.S. each SG has parallel AFW feed arrangements of one air operated control valve (from original I installation) and one Target Rock modulating I solenoid control valve. CR-3 and AN0' utilize two target Rock manuf actured modulating solenoid control valves in parallel per S.G.
B.13. At R.S. loss of IE and non-IE power within the C or I D EFIC channels is annunciated separately. Loss'of non-IE power to the C or D channels at CR-3 and ANO is not annunciated.
B.14. R.S. will utilize an administratively set time delay to filter pressure transients from S.G. low level, S.G. low pressure, S.G. high-high level, and S.G. differential pressure bistable initiate signals. CR-3 utilizes a time delay filter for their S.G. low level initiate only. ANO currently uses no time delays.
B.15. R.S. and ANO have Trip Interf ace Equipment (T.I.E.)
which forms a part of the EFIC actuation logic.
These interposing relay arrays are not used at CR-3.
B.16. R.S. utilizes automatic MFW overfill isolation, but not AFW overfill. CR-3 utilizes Automatic AFV overfill isolation, but not MFW overfill. ANO does not use its automatic overfill isolation capability.
B.17. CR-3 initiates AFW on low level in both steam generator. ANO and RS initiate AFW on low' level in either steam generator.
5415MAJ Page 52 Rev. 3 l
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104415 A-5415 MAJOR NCPe- Work Reques?
ECN Discipline I&C MOD 001 Date 5-ii-'87 VIII.C. Use of Oriainal Plant Valves Of the twenty-five active fluid system components which receive direct comands from EFIC, only four are new; the AW Control valves FV-20531 and FV-20532, and AFW isolation valves HV-20581 and H'/-20582. Additionally, new motor operators are being installed on the previously manually operated gate valves FWS-015 and FWS-016. Clearly, the newly installed items are purchased, designed, and installed to the applicable codes as required by the EFIC AFW system description. Similarly the sigr.als from EFIC and the transducers which receive those signals are designed and installed to the applicable codes. Also,.the valves and valve actuators which receive EFIC comands but which were installed as original plant equipment, and which l have been performing the same safety function, may require i re-certification or other pedigree or qualification i upgrade. Specifically, the'MFW control and start-up valves, the AFW control valves, FV-20527 and FV-20528, and l the ADV's will continue to be used. The functions of each of these valves has not changed, and since initial operation the valves have provided precise, reliable fluid control. What is changed with the upgraded design is that signals and transducers which tell the valves how to respond will now be safety grade, as will their motive power sources. Also, in each case, a safety grade, emergency power backed isolation valve will have been installed in series with each valve. And except for the ADV's the safety grade function of each of these proven dependable valves is also performed redundantly by newly ,
l installed safety grade equipment.
A review of qualification documentation for these components is being perfomed. Upgrading of documentation, l
including testing as required, will be comoleted prior to startup.
l 5415MAJ Page 53 Rev. 3 l
' ' 'l ECN A-5415 MAJOR NCP-- dork Request- 104415 Discipline I&C MOD" '001 Date 5-8-87 i
1 i
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'e m se s 7 e n uo
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sna t l 1 4 i FIGURE VI - EFIC CONSOLE H1SS(E) 5415MAJ Page 54 Rev. 3 J
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NCR, Work Request- 10415 s ECH A-5415 MAJOR i 001 Date 5-B-87 l Discipline f&C MOD' )
1 l
2 li SMUO I; TEM I Dre
"" CRIDTION ltNSTR TA0 NO.
No. !
l L* -!!!O? ,
I I 00NOENSATE STORAGE TANK T-355 LEVEL INO:0 ATOR CW A !
l L*-!O5054 i 2 l STM G"N. A LOW RANGE ZvE.L. CH ANNEL A D40! ATOR l 3 l STM GEN. A LOW RANGE L8VE, CWANNE 5 INO f.ATCR lLI 2050!S l
IL* 2050TA
- 4. I STM GEN. A HiGH RANGE LEVEL, CHANNE A NO::ATOR lL!-205C?S 5 l EIM GEN. A WlGW RANGE LEVEL, CHANNE SIN; :ATOR i i
l 6 l NmATE / TEST MAUllX,18lC CHANNEL A l L*-2050;a A 7 l STM GEN. B LCW RANGE LEVEL, CH ANNEL A IN010 ATOR I L1-10504r B 8 l 57M GEN. B LOW RANGE LEVEL, CH ANNE 5 IN010ATOR
$ l STM GEN. 5 WiGH RANGE LEVEL, CHANNE A IMO:C ATOR l LI-20508 A l(; 205 CSS 10 l STM GEN. S M4H RANGE LEVE. CHANNEL o ;gg:;A70g 1
27 l SIM GEN. A CRE*SURE, CHANNE A INC:0ATOR l FI-205 45 A 1
j 25 l ETM GEN. A PF5.55URE, CHANNEL S IN010ATOR lDI-205455 29 l AFW F.0W 70 STM GEN. A, CHANNEL A INO 0ATOR lF.-51801 1
18~ -!!S 05 j 10 I AEW " LOW TO CTM GEN. A. CHANNEL S IN0!CATOR l
fl l INMATE / TEST MaiRIX, E:lC CHANNEL 5 l l P"-205 4, A 32 l 5'TM GEN. S FFJ S SU81, CH ANNE A IN010ATOR .
l P"-1051;,5
!! l STM GEN S 8RE55URE, CMANNE S IN0!:ATOR l 3A l AFW F.0W TO STM GEN. S, CWANNE. A IN010ATOR lF-5!S07 25 l A=W FLCW TO STM GEN. 5, CHANNE 51N01CATOR j F;-!:001 l
er l E=r :WANNE A STFA55 (H50)-l l 5: lEFi; CHANNE S SYPASS (MS:)-1 l 55 l E*1C. CHANNE C EYPA*,5 ( M50). l l l 54 l E*tf. CH ANNE D SY#A55 ( MSC]_ I l l 55 i v0LTAGE Risu;ATOR tup *LY SRe.v.s.R (v5:1-2 {
i H5-M $!!
fo ' AFW 0 ETM GEN. A '50L. VALVE HV.205 51 (M50)-!
l HS-20577 57 l AFW TO STM CEN. A ISOL. VALVE HV- 205 7 (M5l.)- 2 55 l STM GEN. 5:::. LEvn CO,vRoL CHANNEL A l l
59 I E::0 C.WANNE. A CONTROL DJmAT50 (M50)-l 60 l STM GEN. E:~;. LEVEL 00NTROL CHANNT 5 l
)
I i l E.8: . 0W ANNE. E CONTRE !NmATE 'M50)-1 61 62 l A8W TO STM GE.N. 2 ISOL va:.vE W-2055:(MS )-2 l HS-705 S:
I a l Afri 0 sm GEN.5 SOL. VALVE uv-20573(.v.5:1-2 % 1H5-ZO575 l TABLE VI - EFIC CONTROLS ON H1SS(E) PANEL Page 55 Rev. 3 5415MAJ
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NC9' Work Reques+-- 104415 ECN A-5415 MAJOR
. z..
001 Date 5-8'-87 Discipline I&C MOD
- p. ,g
'TE DESCRIPTION l EI -2057'I S' l APH CONTRO., VALVE PV-20077 D0517;0N INOICATOR IH5-20:27 55 l AFW TD STM EN. A CONTROL VALVE N-20527 l0*-205fl POSMON INO:CATOR SG l AFW C0t#ROL VALVE W-205tl j H5 -10 5 51,___
67 i AFW TO STM GEN. A. 00MTR0; VALVE FV-20$5:
i"I-2052e Bt l AFW CONTR0;. VALVE FV-20$2$ FOSITION !NOICATOR l WS -20526 ,
29lAFW TO STM GEN. S CONTROL VALVE Fv *0525 1::-20sn l 30 ; AFW 00sTRO. vnvE v-:05n m.m0w :NO::.ATOR l
VALVE FV- 0530 lW6-705:2 l 91 } ASW "D STM 3D4. t CONTROL l HS-trazw 104 l AFW :.ROS5Tli VALVE HV-SIS 2b (M50)-2 i HS -!!SI7 l
- 05 l AFW OR055Tif.fVALVE HV-!!S27 (HSC)-2 l _-
lS l AFW PUMP #-315 AMMETER l 117 ' AFW #UM8 P-ite (M5:)-t (M5 0)-2 I HE-!!!DJ 110 l ASW PUMP F.518 STM STOP VALVE W-5080: ~
l ~-3!?01 ,
119 l AFW PUHF P-!!B 0:50 HARE FRE55URE INO:0A*0R l 1 120 l AFW P5T ROK VALVE HV-!!!!! (MS:)-2 l til ) AFW TES~ FLOW 2N01CATOR (OtGITAL) l
!!2 ! A*W P.:M8 P-!!S AMME~ER l
- 13 i AcW P. MS 5-i!P (MS".) -2 l ~~.-3! E 01 ._
- 24 ' AN FUMP F !!9 O!50 HARE FRE55LlRE *.N010ATOR f
l I!1 l SECONOARY SYSTv.5 ANNUNCIATOR /Filf57 OLTT RESET WSC)= A l 11 -!!!!5 INO!OATOR we j Anw EST FLOW Vt4.VE W-hS55 P05 MON ! _t 1174) A4 006 D-316 MO~0R KEYLCCK TABLE VI (CONT) - EFIC CONTROLS ON H1SS(E) PANEL Page 56 Rev. 3 5415MAJ I
) _
l . .
Work Request 104415 A-5415 MAJOR NCR-ECN .
y.ks 5-@B7 Date __
' LIST OF REFERENCES _
l 18, 1983; AFWS review - NUREG 0737 i
1.
Letter; SMUD to NRC; Feb.II.E.1.1; Additional info requested; seismic, T .
t control valve control air; ATW pump protection.
14, 1983; upgraded AFW Sys-Nureg 0737 l l
- 2. Letter; SMUD to NRC; Jan.II.E.1.1.; responds to request from 12-8-82 fo 3.
SER; NRC to SMUD; April 7,1983; Rancho Seco - Status of the AFWS upgrade Review (NUREG 0737 item II.E.1.1).
4.
Standard Review Plan; NUREG 0800, 10.4.9 AFW System (PWR) 5.
Letter; B&W to SMUD; July 9,1984; EFW Third Pump; explains ,
reliability data difference between NRC & B&W. I 28, 1983; EFIC upgrades AFWS; 0737 Items
- 6. Letter; SMUD to NRC; AprilSent 15-1120850-03 Rev 3 of System l l
II.E.1.2 and II.K.2.10.
Description.
7.
Letter; NRC to SMUD; Dec. 8,1982; AFW upgrade Additional Information Request.
- 8. Emergency Feedwater System, B&W Design Review Board (Doc. 1 I
- 80-1125704-00).
62-1149372-00, Apr. ' 84 )
- 10. EFW upgrade for R.S.; Test Spec.;
05-0004; Mar. 25, 1985
- 11. Draft Tech Specs. EFIC/RPS/SFAS; B&W Doc. !
- 12. Anticipated Performance Behavior of the AFW Pumps under extreme conditions with A MSLB with both Nuclear Steam generators at Atmospheric Pressure, Elemer Makay, Report ERC0 - 693, Feb.16,1984.
- 13. Control Roon Implementation of EFIC; July 9,1984 End Extension review.; Starkey; SMUD memo from J. Williams to Distribution.
- 14. Letter SMUD to B&W; Mar. 2,1982; EFIC 3hutdown Bypass; Rejects 4 original shutdown bypass concepts.
Says to go
- 15. Letter; SMUD to B&W; Dec. 13, 1982; Shutdown Bypass.
i
' w/ single shutdown bypass (& Reset)
Rev. 3 Page 57 5415MAJ
1 NCP~
l'ork Reques0- 104415 ECN A-5415 MAJOR 001 Date 5-8-87 ,
- 17. Memo; Wichert to Redeker Oct. 4,1982; Evaluation of 0A.82-003; )
acceptability of Shutdown bypass release. l
- 18. Letter SMUD to B&W (Whitney to Holt); April 6,1982; Feedwater Flow l Versus Reactor Power Comparator Anticipatory Trip Operability Study; Shows F.W. flow data f or normal shutdown. from Apr. 2,1982.
1
- 19. Letter SMUD to B&W; Aug. 30, 1982; FW flow vs. Reactor Power Comparator Anticipatory Trip Operability Study; Startup FW flow from I August 19, 1982.
- 20. Letter SMUD to B&W; Sept. 27, 1982; FW flow vs. Reactor Power Comparator Anticipatory Trip operability Study; shows FW flow vs.
Power for the return to power of Sept. 17, 1982.
- 21. Operability Evaluation of proposed Power to Main Feedwater Flow l Trip; B&W Doc. 51-1135242-01; Sent w/B&W 1etter SMUD-82-227 dated '
Oct. 20,1982. Says it works.
- 22. Letter SMUD to B&W, Nov. 24, 1982; Flow Signal for Flux /MFW Flow J Trip.
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- 24. Letter SMUD to NRC; July 20, 1983; NUREG 0737 II.X.2.10 ARTS; gives details of Flux /MFW flow ARTS.
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- 25. SMUD Memo; Beebe to Daniels; 12-18-85; AFV Power Sources.
- 26. Letter SMUD to NRC; January 17, 1986; Status of EFIC Implementation; I Brief statement of Cycle 8 EFIC System.
b l 29. EFIC Test Procedure, Vitro Doc. TP3801-4009, SMUD 00C. N28.02-309.
- 30. Containment Transmitter Enclosure, Inside Temperature Transmitted During MSLB; Z-ZZZ-M1795,17 pages ; 12-24-85; Bechtel.
- 31. Temperature Rise in level Transmitter Reference Leg Under Transient I condition. (LT-20001 A/B; LT20002 A/B); Calc. Z-RCS-I-0059; 3-28-84; Bechtel.
- 32. HELB Analysis - AFWS changes: ECN A-2806 A, A-2912, A-3094, A-3622, A-3653; Bechtel Calc. M21.30-363, 34 pages; 6-14-83.
Page 58 Rev. 3 5415MAJ l
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R Work Reques~ 104415 l ECN A-5415 MAJOR NCF Date 5-8T87 Discipline I&C M0b 001 l
- 33. AFW upgrade Reliability Analysis for R.S.; Document dated April 1981.
- 34. Reliability / Availability Analysis for EFIC (Vitro); May 1, 1984; Vitro Doc #03801-4340 Rev. A; B&W Doc #32-1010496 01,
- 35. Overcooling effects of a Variable Overfill Protection System for SMUD dated 11-5-82; ' ale; B&W doc. #51-1138358-00.
- 36. BAW-1655, Jan. '81; Main Feedwater Overfill; Evaluates OTSG Differential Pressure overfill parameter. l
- 37. B&W Study; 86-1134596; An Improved Concept for Controlling Main f Feedwater Overfill (36 pages).
- 38. BAW-1686; Aug. '81; Emergency Feedwater Level Rate Control-Control Evaluation sent W/B&W 1etter SMUD 81-120, Apr. 3,1981. Evaluates Rate Limited follower concept. 1
- 39. B&W Doc. 77-1151127-00; Steam Generator Level Accuracy w/Gould Transmitter; sent w/ letter April 30, 1984.
- 40. BAW-1612 Rev.1; March '80; Conceptual Design Study for AFWS feed l rate control for B&W 177 FA plants.
- 41. Deleted b !
- 42. AFW flow rate Flow Orifice Calc.; SMUD Memo; Wichert to Stephenson; f 9-28-81.
86-1123794-00.
- 44. Heat Removal Capability of-SMUD Condensate Storage Tank; Mar 29, 1983; B&W No. 32-1141727-00.
- 46. ECCS Analysis; EFW System Upgrade; B&W doc. #77-1125999-01 Substantiates 801 (actual equipment height) as absolute minumum level.
- 47. Intentionally left blank.
Shows at least 10 mins. to initiate AFW if MFW lost @ 750 psig during nonnal cooldown.
Page 59 Rev. 3 5415MAJ
ECN A-5415 MAJOR NCR Work Request 104415 !
I Discipline I&C MOD 001 Date 5-8-87 l
- 50. MFW Flow Element Differential Pressure; calc. Z-FWS-M1500.
- 51. MFW Flow Element Pressure; calc. Z-MlS15. 1
- 52. Deleted /k
- 53. SER NRC to SMUD; September 26, 1983; " Rancho Seco - Status of the Auxiliary Feedwater (AFWS) Upgrade Review (NUREG-0737 Item II.E.1.1)". )
l
- 54. Letter NRC to SMUD; April 1, 1985; " Status of Auxiliary Feedwater (AFWS) Upgrade Review".
l 55. Single Failure Analysis of EFIC, B&W Doc. 32-1010482-01, prepared by Vitro, March 1983, Vitro No. 3801-1330,
- 56. Memorandum from R. Daniels to V. Lewis; May 28, 1986; RED 86-169; "IE l Information Notice 86-15: loss of offsite power caused by problems in )
Fiberoptic Systems."
- 57. Letter J. J. Mattimoe to J. F. Stolz of NRC dated May 3, 1984 transmitting report on "Effect of Internally Generated Missiles on I I
the Auxiliary Feedwater System Outside Containment" for Rancho Seco Nuclear Generating Station Unit 1".
- 58. Memo; Jerry Williams to Bob Daniels, D.C. Motor Dutz cycles for AFW valves, dated Oct. 28, 1984.
- 59. Memo; Harold Beebe to Ed Dowling, EFIC Electrical change to TDI {
Diesels, Sept. 30, 1986. l
- 60. Report; Task 170 N.I. Calibration Error Final Report, March 1981, B&W document # 12-1125041.
l 61. Memo; Bud Beebe to Rob Roehler, EFIC level sensing failure affecting multiple channels, Oct. 6, 1986.
- 62. Babcock & Wilcox to SMUD letter, AFW upgrade implementation shutdown bypass design review, SMUD 83-108, May 27,1983.
- 63. Calculation summary; Babcock & Wilcox Document Number 86-1167930 Rancho Seco: AFW Minimum Flow Analysis dated May 1, 1987; SMUD Calculation Number Z-FWS-I 0150.
- 64. B&W Study 51-1165937 dated February 3, 1987; " Rancho Seco AFW Flow 4J Limit" (SMUD Document ERPT-I-0016).
5415MAJ Page 60 Rev. 3
ENCLOSURE 4 EFIC Auxiliary Feedwater System Description i
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i Cycle 8 Auxiliary Feedwater System Description (EFIC)
Table of Contents Pace .
11 Preface iii Revision Page 1
1.0 Scope
'l 2.0 System Requirements 9 t 3.0 Design Description
)
3.4 EFIC System Description 13 l Input logic 14 3.4.1 15 3.4.2 Initiate Logic 3.4.3 Trip Logic 16 3.4.4 Vector Logic 18 3.4.5 Control Logic 20 1 3.4.6 EFIC Trip Testing 21 l 3.4.7 EFIC Signal Application 22 )
3.4.8 OTSG Level Sensing 23 'l 3.4.9 Interf ace with Valve and Pump Controllers 24 24 3.5 Annunciation 24 1 3.6 Main Feedwater Overfill Te mination 3.7 Appendix "R" Interface 25 4.0 System Limits, Precautions, and Setpoints. 25 28 5.0 Operation 6.0 Casualty Events and Recovery Procedures 29
- 7. 0 Testing and Maintenance 33 Tables Analog Output Signals 34 1
- 3. 4 -1 Equipment Actuation through the T.I.E. 35 l 3.4-2 AFW System Setpoints 36 l 4.2-1 Flux To Feedwater Setpoint 37 4.2-2 Appendices 38 A List of Figures B Instrumentation Requirements 39 C EFIC. Electrical Cabling Separation Requirements 41 D EFIC Annunciation 46
' - PREFACE i
This document is a detailed description of the AFW System including f EFIC. It includes also a functional description of Atmospheric Dump Valve (ADV) control, MFW isolation control, and loss of Main Feedwater l anticipatory Reactor Trip. For a cursory introduction please read Section 6 and consult the Post EFIC AFW P & ID (Figure 3.1-1).
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REVISION PAGE !
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DATE PAGES REV. i 5-7-87 Added Revision Page; Changed AFW Flow 1, 9, j l 2 25, 29, 1 l l 30 l 1 t
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1.0 SCOPE This document describes the Post EFIC Auxiliary Feedwater (AFW) System.
Any physical changes to the plant necessary to bring the present system to conform to this description including AFW valving modifications, Control Room control and indication modifications, EFIC SG 1evel transmitter installation, etc, are covered by Mod 1 and Mod 123. It also describes the Reactor power versus Main Feedwater Flow Anticipatory trip (Flux /MFW Flow trip) located in the Reactor Protection System, control to l
isolate Main Feedwater (MFW) for steamline break protection and MFW l overfill, and control of Atmospheric Dump Valves ( ADV's) independently from ICS.
l This document is based largely on the AFW System Description written for the Distict by Babcock & Wilcox (B & W Document No. 15-1120580 Rev. 4).
l Functional requirements needed to properly interface the AFW System with the nuclear steam supply (NSS) are taken from that document. Other l
sources of requirements are NUREG - 0578, Short Term Lesson Learned; ,
NUREG - 0667, Transient Response of B & W Designed Reactors; NUREG -
0737, Clarification of TMI Action Plan Requirements.
This document contains the criteria necessary to upgrade the AFW system to substantially comply with the Standard Review Plan Section 10.4.9, Branch Technical Position ASB10-1 and other standards generally applied to new designs. In implementing these requirements, some exceptions may be taken where the improvement in system reliability is so small that the required modification is not justified for an operating plant. Note that "feedwater", as used in this document, refers to AFW unless otherwise stated. i 2.0 SYSTEM REQUIREMENTS The AFW system requirements are listed below.
2.1 NSS Interf ace Requirements i 2.1.1 Maximum Feedwater Flow The maximum allowable continuous AFW flow is 1800 gpm per steam generator (SG). This maximum AFW flow limit is required to minimize flow induced vibration of the steam generator tubes. This limit must not be exceeded at any l
steam pressure.
2.1.2 Minimum Available Feedwater Flow The AFW system must be sized so that a minimum of 475 gpm (total) can be delivered to either one or both SGs at a SG
'A pressure of 1050 psig. This flow must be available for all accident conditions considered in the design basis for the plant even with a sincle active f ailure in the system.
AFWTECD0 Page 1 Rev. 2
7 2.1.3 Maximum Automatic Initiation Time The system shall be designed so that the minimum AFW flow is established within 70 seconds after an initiation signal is reached. This initiation time is based on the requirements to:
A. Maintain continuity in reactor coolant system (RCS) flow in the transition from forced to natural circulation when the Reacter Coolant pumps (RCPs) are tripped.
B. Provide margin to prevent overpressurization of the RCS following a loss of main FW event and reactor trip.
And the desirability of:
C. Reducing the probabiltiy of boil off of the entire inventory of liquid water from the SG's immediately following a loss of main FW occurrence.
2.1.4 Initiation and Control Requirements 1 2.1.4.1 General Requirements The requirements to which the AFW control system '
shall be designed are:
A. The system shall provide automatic actuation of AFW, for the conditions specified in Section 2.1.4.2. The capability for bypassing certain initiations shall be provided for unit startup or shutdown in accordance with the IEEE-279 provisions for shutdown bypasses.
B. The system shall be designed to minimize overcooling following a loss of main FW event.
This feature of the system is not required to meet the single failure criterton.
C. The system, including control valve positioners, sensors, control and actuation signals and their auxiliary supporting systems, shall be designed as safety grade systems to the extent possible. As such, they function independently of the ICS, NNI, and other non-safety systems.
D. Redundancy and testability shall be provided to enhance the reliability demanded ci a safety grade system.
AFWTECD0 Page 2 Rev. 2 D
3 ll E. A single failure shall not prevent actuation _of AW when required. This criterion shall apply to the AFW system and its auxiliary supporting features. In addition to this single f ailure, ;
all failures which can be predicted as a condition or a result of the initiating event I l
requiring AFW shall be considered.
F. Indication of AFW operational availability.,
flowrate and OTSG level shall be available to the operator.
G. The capability for manual override of the automatic functioning of the system shall be i provided. This condition shall be indicated in the Control Room.
H. The capability for manual intiation of AFW shall be provided.
.I. The capability for manual control of AFW shall be provided in the main Control Room. The capability for AFW and ADV control from a remote shutdown panel shall be provided to meet the requirements of 10 CFR 50 Appendix R.
J. The system shall be designed to prevent or minimize cycling of the AFV control valves i during normal plant operation when the AFW system is not in operation.
2.1.4.2. Actuation Requirement AFW shall be automatically initiated after the I occurrence of any of the following conditions: l
- Loss of main feedwater as indicated by the loss of mainfeedwater anticipatory Reactor trip located in the RPS.
- Low level in either steam generator.
- Loss of all 4 reactor coolant pumps.
- SFAS ECCS actuation (high RB pressure or low RC pressure).
AFWTECD0 Page 3 Rev. 2 l-l C
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_. , ,6 2.1.4.3 0,T SG Level
- Control Requirements l
Three level setpoints are required.
A. Following AFW actuation, the level setpoint l
shall be automatically selected to control OTSG l level to approximately 2 feet if one or more RCPs are running.
B. Following AFW actuation, if all four reactor coolant pumps are not running, the level setpoint shall be automatically selected to a level sufficiently high to assure natural circulation within the RCS. This setpoint shall be at least 20 feet.
C. Provision for manual selection of a high level l setpoint of approximately 32. feet shall be provided. This setpoint will be selected by ,
the operator in accordance with operating guidelines and is intended for use during small break loss of ceolant accidents.
- For the purpose of AFV design, " LEVEL" refers to the equivalent height of a saturated liquid column referenced from the top of the lower tube sheet. See Table 4.2-1 for setpoints.
2.1.4.4 Fillrate Requirement The objective of the fillrate control is to minimize overcooling when adding large quantities of AFW during low Decay Heat conditions such as when filling the SG following loss of all RCP's.
If no RCP's are running, the AFW flow rate is controlled by the rate of level increase. A level of 2 to 8 inches per minute has been determined to provide tdequate RCS cooling. This fill rate is varied as function of steam generator pressure in the range of 800 to 1050 psig for the transient conditions which require AFW. Fillrate control is not necessary for the RC pumps running level setpoint.
The level rate limit can to be adjusted at the Channel A and Channel B Cabinets under administrative control.
In operation, the AFW flowrate is modulated to hold the level fill rate or level at the desired value.
AFWTECD0 Page 4 Rev. 2
2.1.5 Steamline Break /Feedwater Line Break A steamline break or feedwater line break which depressurizes a SG shall cause the isolation of the main FW line to any depressurized SG. AFW shall be automatically supplied in accordance with the selection logic below.
l To meet these requirements the following design- shall be implemented:
A. MFW Isolation - Low 'stsam pressure .(below approximately 600 psig) in either SG will isolate the main feedwater line to the affected SG(s).
Once isolated, manuhl action is required to defeat the isolation command if desired.
B. AFW Isolation Logic
- If both SGc are above 600 psig, supply AFW to both SGs.
. If only one SG is below 600 psig, isolate AFW to that SG.
- If both SG's are below 600 psig and the pressure difference between the two SGs exceeds a fixed setpoint-(approximately 100 psig) isolate AFW only to the SG with the lower pressure.
- If both SGs are below 600 psig and,the pressure difference is less than the fixed setpoint, no AFW will be isolated.
AFW isolation logic will reset automatically to allow for changing steam generator conditions. For instance, if the pressure in one steam generator dropped below the 600 psig setpoint r,nd then recovered to a pressure above the l setpoint, AFV would at first be isolated to that SG and then would automatically be fed as the pressure again exceeded the 600 psig setpoint.
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2.1.6 Main Feedwater Overfi11 l Provisions must be made in the design to teminate a main ;
feedwater overfill condition. The steam generator overfill l setpoint should be high enough to prevent spurious tripping of this function (and subsequent MFW isolation) during normal power operation. However, it must also be low enough to minimize the effects of the overfill. See Setpoint Table i
4.2.1.
l AFWTECD0 Page 5 Rev. 2
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_2 l 2.2. Fluid System Requirements i
2.2.1 Branch Technical Position ASB10-1 BTP ASB10-1 places the following requirnent on the AFW system:
A. The auxiliary FW system should consist of at least two
' full capacity, independent systems that include diverse power sources.
1 B. Other powered components of the auxiliary FW system should also use the concept of separate and multiple sources of motive energy. An example of the required diversity would be two separate auxiliary FW trains, each capable of removing the af terheat load of the reactor system, having one separate train powered from either of two AC sources and the other train wholly powered by steam and DC electric power.
C. The piping arrangement, both intake and discharge, for each train should be designed to perstit the pumps to supply FW to any combination of SGs. This arrangement should take into account pipe f ailure, active component f ailure, oower supply f ailure, or control system failure that could prevent system function. One arrangement that would be acceptable is crossover piping containing valves that can be operated by remote manual control from the l Control Room, using the power diversity principle for the valve operators and acutation systems.
D. The auxiliary FW system should be designed with suitable redundancy to offset the consequences of any single i
active component failure: however, each train need not contain redundant active components.
1 E. When considering a high energy line break, the System should be so arranged as to assure the capabiltiy to supply necessary auxiliary FW to the SG despite the postulated rupture of any high energy section of the system, assuming a concurrent single active f ailure.
Note: If the ARI system is not used (and therefore not pressurized) during startup, Hot standby and shutdown conditior:s, then a high energy line break in the AFW system only needs to be considered between the SG and the first check valve upstream of the SG.
AFWTECD0 Page 6 Rev. 2 I
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e vf *w 2.2.2 Water Sources Seismic Category I water sources shall be provided of sufficient volume to remove decay heat for four hours and to subsequently cooldewn the plant to the decay heat removal (DHR) system pressure.
2.2.3 AFV Pump Protection 1 The system design shall protect the AFW pump from runout and cavitation due to high energy line breaks for single failures in the system. Any automatic pump trip features must (a) not override automatic initiation of AFW, or (b) be designed as a Class 1E system.
2.2.4 AFW Support Systems The requirements for diverse power sources and operation with a single failure also apply to the AFW support systems.
These systems include:
- Electrical power to support systems.
- Compressed air for AFW control valves.
- HVAC as applicable.
2.2.5 Cross Connects AFV system shall be designed to allow either pump to feed either steam generator. The crosstie provided for this purpose shall include normally open remotely operated isolation valves.
i 2.2.6 Alarms As a minimum, the following alann outputs are required:
- High SG level. (For SG A and SG B)
- Low SG level to warn approach to low SG level EFIC ;
l initiate. (For SG A and SG B) l j
- Low condensate storage tank level (approach to water l
source transfer)
- AFW Pump Runout
- Low AFW pump suction pressure. (For Pump P-318 and _'
Pump P-319)
Page 7 Rev. 2 ,
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2.2.7 Indicati n As a minimum, the following indication shall be available to the operator.
- AFW flow to each SG. (Channel A and Channel B)
- Low range and wide range SG Level and SG Pressure, (SG A and SG B). (Channel A and B indicated full time and l Channels A, B, C and D available upon request on the
{
plant computer) l
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- Condensate storage tank level (Channel A and Channel B).
- EFIC control system status (level setpoint selected)
(Channel A and Channel B).
EFIC AFW 1evel controls status (active, not active)
(Channel A and Channel B)-
- AFW pump discharge pressure
- Trip Status of the EFIC system. (Channel A and B).
EFIC Channel in shutdown bypass (Channel A,B,C, and D).
- Continuous actual valve position for AFW control valves FV-20527, FV-20528, FY-20531, FV-20532.
- AFW isolation valves HV-20577, HV-20578, HV-20581, HV-20582, and AFW flow test valve FV-31855 shall indicate valve open or closed.
2.2.8 Physical Separation i
System components and piping shall have sufficient physical l separation or shielding to protect the essential portions of the system from the effects of internally and externally generated missiles.
Functional capability of_ the system shall also be assured for !
fires. Specific channel separation requirements to meet !
IEEE-279, HELBA, Missile, and Appendix R requirements are shown in Appendix "C".
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l 2.2.9 Fluid Flow Instabilities The system design shall preclude the occurence of fluid flow ]
instabilities; e.g., water hamer in system piping during normal plant operation or during upset or accident conditions.
2.2.10 Doerational Testing Provisions shall be made to allow periodic operations te . ting.
Paga 8 Rev. 2 AFWTECD0
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w 2.3 Guides end References I The below listed guides and references are those general references l used for the design of the EFIC System and its functional Additional guides and l interaction with the Rancho Seco Plant.
standards for the installation of individual components other than EFIC will be covered by the specific installation documentation.
A. NRC Documents _
NUREG - 0800 Standard Review Plan Short Term Lessons Learned Report NUREG - 0578 Transient Response of B & W Designed Reactors NUREG - 0667 Clarification of TMI Action Plan Requirements NUREG - 0737 B. IEEE Standards 279-1971 Criteria for Protection Systems for Nuclear Power Generating Stations (for initiation portions of AFW System) 323-1971 Standard for Qualifying Class lE Equipment for Nuclear Power Generating Stations 344-1971 Recommended Practices for Seismic Qualification of Class 1E Equipment for Nuclear Power Generating Stations 3.0 DESIGN DESCRIPTION 3.1 Sumary Description The AFW system consists of two interconnected trains capable of supplying auxiliary feedwater (AFW) to either or both SG's by automatic or manual initiation and control. The nomal source of water is the condensate storage tar.k, however the Folsom South CanalA and the onsite reservoir are also available as secondary sources.
simplified piping and instrumentation diagram for the " Post EFIC AFW System" Figure 3.1-1, shows the AFW System and portions of the MFW and Main Steam Systems in their operating fom as modified by the changes included in Mod 1.
In the flow path between the AFW pumps and the SG's there are isolation valves, check valves, control valves, flow instrumentation, and pressure instrumentation to control and monitor The fluid system design is described the flow of AFW toThe theinstrumentation SG's. system design is described in in Section 3.2.
Section 3.4.
3.2 Fluid System Desian The AW system is designed to provide a minimum of 475 gpm the SG's at 1050 psig within 70 seconds of system initiation signal. The system is designed as two interconnected trains with redundant components to insure that the system will meet these requirements even with a single f ailure.
Page 9 Rev. 2 AFWTECD0 0
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3.2.1 Suction The primary water source for both AFW trains is the Seismic Category I condensate storage tank, T-358. Although there are other connections to this tank, they draw through an internal stand-pipe which assures that a minimum of 250,000 gallons is held in reserve exclusively for the AFW system.
This volume of water will remove decay heat (plus RC pump heat for 2 pumps) for approximately 13 hours1.50463e-4 days <br />0.00361 hours <br />2.149471e-5 weeks <br />4.9465e-6 months <br />. This volume will also be sufficient to' remove decay heat plus cooldown to allow cooling by the Decay Heat Removal (DHR) System in approximately 10.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> or allow hot shutdown for approximately 5.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> followed by a 5 hour5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> cooldown Water (50 is supplied degrees F/hr) to DHR System changeover.
from this tank to the AFW pumps by separate 8-inch lines containing locked open manual valves FWS-045, FWS-046, MCM-057, and MCM-058.
Alernative AFW system suction sources are available from the on-site reservoir and the Folsom South Canal. These alternate sources enter the cross connect in the suction piping between locked closed manual valves PWC-076 and PWC-079. Suction must be manually transferred from the condensate storage tank to the reservoir or the Folsom South Canal by opening the locked closed manual valves PWC-076 and PWC-079, closing the locked open manual valves MCM-057 and MCM-058, and either:
(1) operating the Folsom South Canal transfer pumps and valves or (2) opening motor operated valve HV-43011 to l obtain gravity flow from the on-site reservoir. The suction j cross connect also includes pressure r>tief valves PSV-31800 and PSV-31900. The operators are alertad via IMDS to perform this suction transfer by redundant, low level alarms from safety-grade instrumentation on the condensate storage tank. I l
I 3.2.2 Pumos and Discharae Cross-Connect AFW Train B pump, P-318, is a combination turbine-driven and motor-driven pump with both the turbine and electric motor on a common shaft. Either motive source can drive the pump at i its rated capacity of 840 gpm at 1150 psig with a normal minimum flow of 60 gpm. The turbine drive is used as the primary motive source for this pump. The motor drive can be manually initiated, and is powered from a diesel backed emergen:y bus.
AFV Train A pump, P-319, is a motor-driven pump which has the same rated capacity and minimum flow as the Train B pump.
Page 10 Rev. 2 AFWTECD0 A
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The pumps discharge through check valves and locked open manual valves into 6-inch cross-connected discharge lines.
The cross-connection line contains two normally-open motor-operated valves (HV-31826 and HV-31827). The valves are powered from separate diesel backed lE sources. This cross-connect pemits either pu@ to feed either or both steam generators, i
3.2.3 Auxiliary Feedwater Flow Control Valves The flow of AFW to steam generator A is controlled by a normally open pneumatically operated control valve, FV-20527, in parallel with a nomally open modulating solenoid operated control valve, FV-20531. Flow to steam generator B is i l
controlled in a similar manner using valves FY-20528 (pneumatic) and FV-20532 (solenoid). The pneumatic operated valves which fail open on loss of air pressure have a back-up l supply of air available from a seismic class I source which ,
enables the valves to be operated for up to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> following a loss of the plant air supply to the valves. The solenoid operated valves are DC battery backed. Initiation and control instrumentation is described in Section 3.4 of this report.
The class I backup air supply is described in Section 3.2.7.
3.2.4 Auxiliary Feedwater Isolation Valves j In line with each normally open AFW control valve is a r
nomally closed AFW isolation valve; HV-20577, HV-20581, l l
! HV-20578, and HV-20582. These valves receive open and close I l
comands from the EFIC vector logic and can be manually opened or closed from the main Control Room. Section 3.4, I' further describes this control. All four valves are powered by non-interruptable D.C. busses.
3.2.5 Pumo Minimum Flow and Test Lines l
Minimum flow and test lines are connected to the discharge piping of both pumps. The minimum flow required for pump protection is maintained with normally open flow paths to the condenser. The manual valves FWS-051 and FWS-052 located in l
the minimum flow lines shall be locked open whenever the secondary coolant system is the primary cooling medium for l
l the RC system.
Page 11 Rev. 2 AFWTECD0 l
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Full flow test capability is provided through a 6-inch line which intersects the AFW system cross-connect between the two I
nomally open motor-operated valves HV-31826 and HV-31827.
This full flow test path is isolated f rom the cross-connect during normal operation by normally closed manual valve FWS-055 and pneumatically operated control valve FV-31855.
Either AFW train can be full-flow tested by opening valves FWS-055 and FY-31855 and starting the appropriate AFW pump.
l The full capability of both AFW trains to supply AFW on l
demand is maintained during the test since either an EFIC channel A or B AFW initiation signal will result in automatic closure of valve FV-31855. The AFW system is, therefore, automatically restored to its nomal configuration, even in the unlikely event that testing were in progress at the time of system initiation.
3.2.6 Steam Sopoly for the AFW Turbine (K-308)
Steam supply for the AFW pump P-318 turbine (K-308) is obtained from both steam generators through six-inch lines containing check valves MSS-051 and MSS-052, locked-open manual valves MSS-049 and MSS-050, and normally-opened motor operated valves HV-20569 and HV-20596. The check valve and motor operated valve provide redundant isolation capability to preclude blowing down the good steam generator in the event of main steam line or feed line break. Downstream of these valves the lines join to fom a comon supply to the pump turbine. Upstream of the turbine is a normally closed DC motor operated valve FV-30801. A description of the controls for this valve is contained in Section 3.4.
Turbine exhaust is vented to the atmosphere.
3.2.7 Back uo Air Sucoly As Reauired for EFIC Related Pneumatic Valves The nomal air supply for control and actuation of the AFW control valves FV-20527 and FV-20528, MFW valves FV-20525, FV-20575, FV-20526 and FV-20576, cnd Atmospheric Dump Valves PV-20562A, B, C; PV-20571A, B, C comes from the nomal plant air supply which is not a safety system. To assure that the AFW valves and ADV's will function properly even in the event of loss of offsite power or other loss of nomal air supply, and that the MFW valves will close and remain closed if l required by the EFIC, a two hour back-up supply of air is provided. The back-up system is seismic class I and, except l for low pressure indication, functions totally independent of electrical power supplies. It is a four train supply system with one train supplying air to FV-20527, FV-20525, and FV-20575; one train supplying FV-20528, FV-20526, and FV-20576; one train supplying air to PV-20562A, B, and C; and one train supplying air to PV-20571A, B and C. Three of the trains are associated with "A" channel components only, while Channel train.
the train feeding PV-20562A, B and C is a "B" Each train uses a set of high pressure air bottles headered through a pressure reduction valve to supply air to the nomal valve control and actuation air supply at a pressure of 85 psig. Since the nomal air supply pressure is Page 12 Rev. 2 AFWTECD0
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approximately 100 psig, the back-up supply will only function if the nomal supply is unable to. Check valves and excess flow check valves are used to prevent flow from the back-up supply into the nomal supply and to isolate a depmssurized branch of the back-up air supply. Backup supply to the MFW valves will assure only the EFIC closure function of the valve.
i 3.3 Supportino Systems The AFW system valves and pumps, including pump motors and turbine are self-contained entities without dependencies on secondary support systems (exclusive of electrical sources discussed below).
The EFIC cabinets are dependent upon sufficient cooling for the building in which they reside (NSEB).
3.3.1 Electrical Fower The two AFW trains are powered from diverse power sources.
AFW pump P-318 is turbine driven with an AC powered back-up motor, and AFW pump P-319 is AC motor driven. Each of the pump motors are powered from a diesel generator backed emergency bus. The following valves required to operate the AFW system are also on AC power with back-up power from a diesel generator: HV-20569, HV-20596, HV-31826, HV-31627, and HV-20S65.
! In the highly unlikely event that there is a concurrent loss of offsite power, reactor or turbine trip, and f ailure of all !
emergency diesel generators, the AFV system would remain functional although with reduced redundancy. AFW pump P-318
_(only) would be available and driven from its turbine. P-319 would not be available. Valves HV-31826, HV-31827, HV-20569, HV-20596 and HV-20565 would remain in their last position (unless operated by hand locally). All other AFW functions would remain in service for at least 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.
3.3.2 Service Air The normal air supply to the EFIC related pneumatic control j valves is provided by the plant air system. In the event !
that the air supply to these valves is interrupted or lost, a {
back-up supply will be available for at least two hours; see section 3.2.7.
3.4 AFW Initiation and Control (EFIC) System Description !
l It should be noted that all setpoints and values used in the following discussion are approximate and are given for purposes of illustration. For actual setpoints, see Table 4.2-1. l The emergency feedwater initiation and control system (EFIC) is a l logic, control and electrical switching system designed to provide y i
the following: ;
i
- 1. Initiation of auxiliary feedwater (AFW),
- 2. Control of AFW flow to maintein steam generator level at l I
appropriate setpoints, J am m nn p,n, 1g p ,y, p
I
%v
- 3. Level rate control when required to minimize overcooling, i
- 4. Isolation of the main feedwater lines of a depressurized steam generator,
- 5. The selection of AFW flow to the appropriate steam generator (s) j
- under conditions of steamline break or main feedwater or emergency feedwater line break downstream of the last check l
valve.
- 6. Control the Atmospheric Dump Valves ( ADV's) independent of ICS Control should minimize challenges er other non-mar.ual control. !
to the main steam safety valves, and allow cooldown controlled from the main control room or the Appendix "R" shutdown area.
1 The emergency feed initiation and control system (EFIC) functional logic 1
j is illustrated in Figures 3.4-1 thru 3.4-8. Figure 3.4-1 illustrates the
' EFIC organization while the remaining figures illustrate the individual logics that comprise the system. The interface of the EFIC with the secondary plant is illustrated in Figure 3.1-1.
The EFIC - see Figure 3.4-1, consists of four channels (A,B,C, & D).
l
' Each of the four channels are provided with input, initiate, and vector ,
logics. Channels A and B also contain trip logics and control logics.
Channels A and B monitor initiate signals f rom each of the four initiate logics by means of the trip logics to transmit trip signals when requi red. Channels A and B also exercise control of AFW flow to the SG's by means of control logics to mainthin SG level at prescribed values once AFW has been initiated. Channels A and B also monitor SG A and B overfill signals originating in the Channel A, B, C and D initiate "A" Main Steam i logics. In addition Channel A controls the ADV's on the Line. Channel B controls the ADV's on the "B" Main Steam Line.
3.4.1 Input Looic The input logic, depicted in Figures 3.4-3a, 3.4-3b and 3.4-3c The input logic:
is located in each of the four EFIC channels.
- 1. Powers and monitors 6 analog signals; Steam Line Pressure
("A" and "B"), Wide Range Level (SG "A" and SG "B"), Low Range Level (SG "A" and SG "B"),
- 2. Provides input buffering as required,
- 3. Incorporates " bistable" logic to compare analog signals to 12 appropriate setpoints to develop digital signals based on analog values; S.G. level low, S.G. level high, S.G. level high-high, steam pressure less than shutdown bypass permissive, steam pressure low, steam pressure "A" i
less than "B", steam pressure "B" less than "A".
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- 4. Provides for calibration and testing of Analog monitoring equipment.
- 5. Provides for buffered Class lE output signals and isolated "n-lE output signals. Output signals are i sumarizea in Table 3.4-1.
- 6. Provides signals to other logic within the same channel.
- 7. Provides for the insertion of time delays so that '
transient phenomena, which momentarily force EFIC monitored parameters into initiate regions, do not produce spurious initiations.
3.4.2 Initiate Looic The initiate logic, depicted in Figure 3.4-4 is located in each channel. The initiate logic within each channel derives its inputs from input logic in the same channel and provides outputs to the " TRIP LOGICS" in both channels A and B (see 3.4.3 below), and outputs to initiate logic in every other channel. Initiate logics within channels A and B also output a " loss of all RCP's" signal to " CONTROL LOGIC" within their respective channel.
The initiate logic issues a call (to the trip logic) for AFW initiation when:
- 1. All four RC pumps are tripped.
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- 2. Loss of MFW anticipatory reactor trip is present.
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- 3. The level of either steam generator is low.
- 4. Either steam generator pressure is low.
Other functions of the initiate logic are:
"A" !
- 1. Issue a call to the trip logic for Steam Generator isolation when SG A pressure is low.
- 2. Issue a call to the trip logic for Steam Generator "B" iso?stion when SG B pressure is low.
- 3. Issue a call to the trip logic for isolation of MFW to Steam Generator A when SG A level exceeds the high-high level setpoint.
- 4. Issue a call to the trip logic for isolation of MFW to i
Steam Generator B when SG B level exceeds the high-high level setpoint.
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- 5. Provide for shutdown bypassing (manually initiated locally at the EFIC cabinet or f rom the Control Room) which blocks the logic of the Steam Generator low l' level, high-high level, low pressure, and loss of all four RCP's signals out of the initiate logic. Tne shutdown bypassing function is combined with a icw I steam generator pressure pemissive signal suen that manual initiation of shutdown bypassing can occur on a per channel basis, but will automatically be reset (i.e., signal block will be removed', on a per channel basis if the pressure setpoint is exceeded.
- 6. Provide for maintenance bypassing of initiate outputs to the Trip Logics. Interties between the channeI initiate logics preclude more than one channel f rom being in maintenance bypass at any time.
Maintainenance bypassing of a NI/RPS channel will /
, preclude or countermand maintenance bypass of any l other EFIC channel intiate logic (e.g., NI/RPS !
channel A placed in bypass will preclude or countemand maintenance bypassing of initiate logics f in EFIC channels B, C, and D.)
- 7. Provide for local manual initiation of a) Flux /MFW flow AFW initiate (will not trip RPS) b) loss of any or all RCP's (will not trip an RCP) c) either spare AFW initiate trip ( Anticipatory i l
Trip 1, Anticipatory Trip 2) d) Shutdown Bypass (when bypass permissive exists) ~
e) Bypass Reset 3.4.3 Trio Loaic The trip logic is illustrated in Figure 3.4-5. Trip Logic 7A, 8A, 9A,10A, ll A, and 14A are located in EFIC Channel A. Trip Logics 78, 88, 9B,10B, llB and 14B are located in EFIC Channel B. No trip logics are located in either Channel C or Channel D. The trip logic of the EFIC employs a 2(1-out-of-2) fomat. The format provides for !
easy one step testing from the input logic test switches ;
to the initiated controllers. Testing is f acilitated by ;
j locating the AND portion of the 2(1-out-of-2) logic in the trip interf ace equipment (T.I.E.). A characteristic of l coincidence logic systems is that a test stimulus inserted ,
j at the input propagates to the first AND element of the '
system and no further. Since the first AND element of the EFIC is in the TIE, test stimuli inserted at the input logic will be propagated to each appropriate controller in the TIE. EFIC testing philosophy is discussed in Section
- 3. 4. 6.
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l The trip logic is provided with five trip networks which l interf ace with the TIE. These networks monitor the appropriate outputs of the initiate logics in each of the channels. They output a full trip when a [2(1-out-of-2)]
network exists in the intiate logic. Thus, for trip l modules located in Channel "A", AFW initiate signals from all four Channels would be combined to produce a full AFW initiate trip signal when ("A" or "B") and ("C" or "D") l are present. However note that for trip modules located i
in Channel "B", the full trip condition occurs when ("A" l or "C") and ("B" or "D") are present.
The five trip networks per channel are:
- 1. Auxiliary feedwater initiate
- 2. SG A isolate
- 4. SG B isolate
Interf ace Equipment (TIE) cabinets. The trip interf ace l equipment actuates AFW system and related components as a l result of these signals. The components actuated from the l TIE are summarized in Table 3.4-2. l l
An addition to the above, trip modules (called control enable modules) located in Channel "A" and Channel "B" l
will " trip" whenever a full trip is output from the AFW initiate trip module. The control enable module in turn activates the normally domant control logic. The control logic will remain activated until the control enable modules are manually reset. This allows the Control Room i
operator to place the AFW Initiate trip into manual in l
order to release EFIC commands to AFW components without defeating the automatic S.G. level control.
The AFW trip logics (logics 7A and 7B) are input by Safety Features Actuation System (SFAS) trip signals to assure that AFW is initiated coincident with Emergency Core Cooling actuation.
For each trip function, the trip logic is provided with two manual " trip" switches located in the Control Room.
j This affords the operator a means of manually initiating a selected function by depressing both switches. The use of two " trip" switches allows for testing the trip busses and also reduces the possibility of accidental manual initiation.
AFWTECD0 Page 17 Rev. 2 l
Once a trip of the trip bus occurs (i.e., once tne trip bus has sent a signal to the TIE), the trip condition will remain until it it manually reset. A " reset" switch and a
" manual" switch are also provided in the Control Room for each of the five trips in both Channel A and Channel B.
The " reset" switch is a momentary contact button which allows the operator to clear a trip signal from the trip bus af ter the initiating conditions have cleared. The
' man 3'aaT#~ switch is a momentary contact button which allows the operator to clear a full trip signal from the trip busses af ter the trip has occurred but before the initiating conditions have cleared. This allows the operator to take manual control of EFIC actuated equipment to optimize response to the initiating condition.
Whether cleared by the " reset" or the " manual" switches, the trip signal will be re-established if initiating conditions re-initialize; i.e., if the conditions which caused the trip return to acceptable values and then those conditions (or any other) re-enter a trip region.
Both the " manual" and the "mset" switches are also used in conjunction with the " trip" buttons to test the trip ci rcuit s. Each of these switches are located in the main Control Room and locally in EFIC Cabinets A and B.
Trip signals are transmitted out of the EFIC to the TIE by activating a solid state relay, thereby gating power onto the trip busses. In this manner, the EFIC provides power to energize the control relays in the trip interf ace eouipment (TIE) whose contacts form the AND gates in the controllers , The TIE also provides signals to the EFIC in response to half trip conditions for test purposes.
3.4.4 Vector Loaic The Vector logic is shown on figure 3.4-6. The function of the vector logic is to determine whether AFW should not be fed to one or the other steam generator. This is to preclude the continued addition of AFW to a depressurized steam generator and thus minimize the overcooling effects of a steam leak. Each vector logic may isolate AFW to only one steam generator or the other, never both.
There are four sets of vector logic; one in each channel of EFIC. Each set of vector logic receives steam generator pressure infomation from bistables located in the input logic of the same EFIC channel. The pressure infomation received is:
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- 1. steam generator "A" pressure less than 600 psig
- 2. steam generator "B" pressure less than 600 psig
- 3. steam generator "A" pressure 100 psid greater than steam generator "B" pressure I
- 4. steam generator "B" pressure 100 psid greater than steam generator "A" pressure Each vector logic also receives a vector / control enable signal from both EFIC channel A and channel B when AFW is initiated. l The vector logic develops signals for open/close control of steam generator "A" and "B" auxiliary feedwater valves.
The vector logic outputs.are in a neutral state until enabled by the control / vector enable from the channel A or l
B trip logics. When enabled, the channel A vector logic
! can issue close comands to valves FV-20527 and FV-20528.
Channel B can issue close commands to FV-20531 and FV-20532. Channel C can issue open or close comands to HV-20578 and HV-20581. Channel D can issue open or close comands to HV-20577 and HV-20582.
l The valve open/close comands are detennined by the relative values of steam generator pressures as follows:
Pressure Status SG "A" Valves SG "B" Valves If, SG "A" & "B" 600 psig Open Open If, SG "A" 600 psig & Open Close SG "B" 600 psig l IF, SG "A" 600 psig & Close Open SG "B" 600 psig l If, SG "A" 600 psig
& SG "B" 600 psig SG "A" & "B" within Open Open 100 psid AND SG "A" 100 psid SG "B" Open Close SG "B" 100 psid SG "A" Close Open AFWTECD0 Page 19 Rev. 2
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.- .I All commands will automatically reset for a change in pressure status, ,
e.g., if pressure in SG "A" falls to 500 psig while SG "B" stayed at !
900 psig, AFW would be isolated to-SG "A". -If subsequently the l pressure in SG "A" increased to above 600 psig, AFW would be i re-admitted to SG "A". q 3.4.5 Control Logic The control logic is shown in Figure 3.4-2.
Control logic is located in EFIC Channels A and B only. )
The control logic in Channel A controls level in steam generators "A" and "B', and steam overpressure control for steam line "A" only. Likewise, the control logic in Channel B controls level-in steam generators "A" _and "B",
and steam overpressure control for steam line "B" only.
3.4.5.1 Steam Generator Level Control If the AFW system is initiated with one or more Reactor Coolant Pumps running, the level control logic in EFIC channel A will be " enabled" by a ;
signal from the A and/or B channel' trip logic and i will send control signals to AFW flow control valves FV-20527 and FV-20528 (feeding steam generators A and B respectively)(to level of approximately 2 feet. Seemaintain a Table 4.2-1 for exact setpoints).
If all four of- the Reactor Coolant Pumps are not running, the control logic in channel A will automatically select a level setpoint high enough-to assure good natural circulation characteristics in the RCS. The natural circulation setpoint is approximately half way up I the steam generator. To minimize overcooling effects on the RCS while filling to this higher i level, the level control employs a level " rate of increase" control which uses steam generator pressure as a feedback parameter. In this way, the rate of level increase is controlled such that it will not rise faster than approximately 8 inches per minute if the steam pressure maintains 1050 psig or greater. This rate of increase would decrease linearly with decreasing steam pressure to a value of approximately 2 inches per minute at a steam pressure of 800 psig or below.
A third level setpoint called the ECC setpoint (for EMERGENCY CORE COOLING) can be selected if all fcur Reactor Coolant Pumps are off. The operator can select a high level setpoint of approximately 31.75 feet by pushing a button in the Control Room. This option is intended for use during scme LOCAs, and utilizes the same rate of fill limits as the natural circulation I setpoint.
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Level control logic in EFIC channel B, controls level in both steam generator A and B in a similar fashion. Channel B controls AFW flow control valves FV-20531 and FV-20532.
Individual manual control of all four AFW flow control. valves and all four AFW isolation valves is possible from the Control Room whether or not AFW has been initiated.
3.4.5.2 Steam Generator Pressure Control Steam line overpressurization control is aided by the pressure control logic in EFIC. EFIC Channel A pressure control monitors steam line "A" only.
EFIC Cnannel B monitors steam line "B" only. ;
Pressure control logic constantly monitors l pressure in one steam line only and if the i pressure exceeds a setpoint will progressively open the Atmospheric Dump Valves (ADV's) on that steam line. The setpoint is to be set higher than the post reactor trip Turbine Bypass Valve setpoint, but lower than the lowest expected opening setpoint of any steam line code safety )
valve.
l 3.4.6 EFIC Trip Testing The EFIC System is fully testable on a per channel basis during nomal plant operation. Testing is fully in )
i compliance with IEEE 279 sections 4.9 and 4.10; from sensor input to trip actuation. Testing will neither )
initiate nor prevent initiation of AFW. Figure 3.4-7 illustrates the test philosophy of the EFIC in simplified fem for one EFIC trip function (e.g., AFW initiate trip). For purpose of the following discussion, the test pushbuttons associated with each bistable are capable of l forcing the bistable input into the trip region. The
! bistables employ a low dead band so the bistable will reset once the pushbutton is released.
l I
l Completed trip testing (input to controllers) may be !
initiated from the input logic bistable module in each of the channels. Depressing the pushbutton in Channel A will trip the Channel A bistable and:
- 1. The Channel A initiate logic will transmit initiate signals to both the Channel A and Channel B trip logic.
- 2. The Channel A and Channel B trip logics will half trip (trip one of the two trip buses).
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- 3. The Channel A and Channel B trip logics will latch in the half trip. The half trip will be retained after q l
t reset of the bistable. This tests the latching ci rcuit.
I
- 4. Each controller in the TIE receiving the half trip i will acknowledge the half trip by transmitting a test confirmation signal back to EFIC. l l
- 5. A full complement of test confim signals will !
satisfy the AND gate in both Channel A and B. The result is that the confim lanps would indicate test j success.
- 6. The trip logic reset switches in the Control Room or 1 i
locally in the EFIC cabinets can now be depressed to '
reset the half trip. The confim lamp should go out.
l I
- 7. If some, but not all, controllers were to respond due l
to a malfunction, the confim lamp will flash.
- 8. The foregoing tests may be conducted from each channel in turn to test the ability to transmit trips from all channels. ;
- 9. The foregoing tests may be conducted for all trip functions from all channels for complete trip testing.
- 10. Tests as described above may also be conducted by use of the local and remote manual trip and reset switches. This will test only the trip module and j TIE; not the initiate logic. ;
3.4.7 EFIC Sianal Aeolication j
Figure 3.1-1 illustrates the application of EFIC signals. j i
Salient features of the arrangement are:
- 1. The channel A AFW trip signal starts the electric emergency feedwater pump, P-319. The channel B trip signal admits steam to the turbine powered auxiliary feedwater pump, P-318. With this arrangement, at least one pump will be started even with a single f ailure of the A or B trip logics.
AFW will be initiated as in 1 above. In addition, the trip logics in channels A and B will issue SG "A" ,
main feedwater isolation trip signals. The channel A trip logic will isolate SG "A" main feedwater by closing the MFW control valve, S.U. control valve, and MFW block valve on the "A" MFW line (i.e.
FV-20525, FV-20575, and HV-20529) . The Channel B '
trip logic will isolate "A" MFW by closing the MFW isolation valve on the "A" MFW line (i.e. HV-20515) .
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- 3. Isolation of SG "B" main feedwater lines occurs in the same way as described in 2 above for SG A except that the Channel A and B SG "B" main f eedwater trip logics are e@loyed. Channel A will close FV-20526, FV-20576, and HV-20530. Channel 11 will close HV-20516.
- 5. Since MFW isolation is commanded out of the trip logics, the isolation command will not automatically reset if pressure in the SG recovers. The isolate '
command will, however, be removed if the SG isolation trip logic is taken into manual by pushing the manual l
or reset pushbutton in the Control Room. ,
l
! The Auxiiiary Feedwater flow path to each generator i 6.
contains two control valves in para'ilel and an l isolation valve in series with each of the control valves. This assures feeding of both stearr f generators even with the presence of a sin-11e valve I I
or control failure. '
i Atmospheric Dump Valves ( ADV's) PV-20571 A, B, C and j
' 7.
f PV-20562 A, B, C are modulating control valves which relieve main steam to the atmosphere from the main steam line "A" and main steam line "B" respectively. ;
l EFIC Channel A will continuously monitor pressure in l main steam line "A" and will open PV-20571 A, B, and l l
l C if pressure in that line exceeds a setpcint. EFIC ;
Channel B will similarly control PV-20562 A, B, and C, j I 8. Both the AFW control valves and the ADV's have l I
manual / auto control stations located in the Control l Room. The AFW vavles, FV-20527, FV-20531, FV-20528, and FV-20532, have one manual /suto station each, l located on HlSS. For the ADV's one manual / auto 1 station will control PV-20571A, B, and C in parallel, i and another will control PV-20562A, B, and C. These !
two stations will be located on H1RI. Manual positioning of the valves will be possible at anytime !
(whether or not EFIC has initiated AFW). Bumpless l transfer from EFIC auto control to manual control is 2
l provided.
]
3.4.8 OTSG Level Sensing Figure 3.4-1 Sheet 2, contains the arrangement for OTSG !
level sensing. Allowable instrument error requirements l are given in Appendix B. l 1
I To provide for low level control and low level initiation I
signals for the auxiliary feedwater, four level transmitters (dP transmitters) per SG are used. The l sensing lines for these transmitters will be connected :
between level taps located 156 inches above the top f ace l of the lower tube sheet and te level taps at 6 inches above the top face of the lower tube sheet. g 1 t
i
. i To provide high level control and overfill protection The signals, four level transmitters per SG will be used.
upper sensing connections will be taps at 619 inches above the top f ace of the lower tube sheet. The lower sensor connections will be 6 inches above the top f ace of the lower tube sheet.
Both the low and high S.G. level signals are altered within EFIC to compensate for density variations in the liquid and the pressure contribution of steam between the liquid level and the upper level tap. EFIC S.G. levei indication will therefore indicate true liquid height above the lower tube sheet, when low flows in the S.G.
exist (i.e., during post reactor trip operatdon).
3.4.9 Interf ace with Valve and Pumo Controllers All valve and pump controllers shall be designed such that signals f rom the EFIC system will have priority over Also, other comands except equipment protection ccmands.
except for the MFW isolation signal to the MFW start-up and control valves, when an EFIC trip signal is placed in !
manual or is reset, the controller design shall be such that valves will not change position and pumps will not change state without a specific additional manual comand. When the vector logic close comand to an AFW control valve is removed, the control valve shall be positioned as required by the AFW control system (or the l manual control as selected) until the operator resets the l
automatic control function. l Annunciation 3.5 Many annunciated EFIC points will be available to the Control Room ,
operators via the IDADS plant computer. These points are listed i
in Appendix "D".
An IDADS generated alam will warn the Control Room operators when steam generator levels are approaching the EFIC low level setpoint which initiates AFW.
In addition, an annunciator window will show that EFIC has initiated AFW and/or isolated MFW to a steam generator.
3.6 Main Feedwater Overfill Termination The EFIC System, as required in Section 2.1.6, is designed to provide signals for termination of main feedwater Thisto a steam capability generator on approach to an overfill condition.
will be present for initial startup of EFIC, however, the overfill setpoint will be set at its maximum value of 619". This will allow data collection to detemine a safe margin between operation at high power levels and the trip setpoint. Implementation of main feedwater overfill termination is accomplished by EFIC trip circuits and MFW valve closures as is done for MFW isolation on low SG pressure, however there is no automatic initiation of AFW concurrent with SG overfill.
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Interface 3.7 Appendix "R" To integrate the new AFW and ADV control modes into the Appendix "R" mandated shutdown and cooldown procedure, some EFIC instrumentation and controls which are duplicates of those located-in the Control Room will be located at the Appendix "R" shutdown controls area.
Isolation switches at EFIC Channels A and B will transfer and isolate the controls from the Control Room to the Appendix "R" shutdown area. These switches also provide Class 1 isolation between EFIC and the Appendix."R" shutdown area.
EFIC Channel A will provide SG "A" and SG "B" level and SG."A" pressure indication to the shutdown controls area. Channel A will also interface with the shutdown controls area via three hand / auto controls; one each for FV-20527, FV-20528, and PV-20571 A, B and C. EFIC Channel B will provide SG "B" pressure and a hand / auto control for PV-20562A, B and C.
4.0 SYSTEM LIMITS, PRECAUTIONS AND SETPOINTS 4.1 Limits and Precautions 4.1.1 AFW Flow limits Maximum allowable continuous flow - 1800 gpm/SG Minimum required flow - 475 gpm Total flow to both generators, with 1050 psig lA pressure in the generators 4.1.2 AFW Pumo Suction Pressure P-318 minimum required NPSH -.18 feet at 840 gpm, 28 feet at 1200 gpm P-319 minimum required NPSH - 18 feet at 840 gpm, 28 feet at 1200 gpm 4.1.3 System Limits (Desien)
Pressure - 1301 psig Temperaure -
1150F 4.1.4 Minimum Reouired Pumo Flow P-318 - 60 gpm P-319 - 60 gpm AFWTECD0 Page 25 Rev. 2
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Setpoints 4.2 All setpoints given in this section and defined as " normal" are instrument calibration points. Instrument string errors as defined in Appendix B were used in the analyses to determine the conservation maximum and minimum setpoint values. The maximum and minimum setpoints represent the earliest and latest assumed actuation point for use in anlaysis.
For the purpose of this discussion, " Level" refers to the I equivalent height of a saturated water column referenced from the top of the lower tube sheet.
4.2.1 Flux to Main Feedwater Flo.w Ratio Setpoint The flux to feedwater ratio setpoint is shown on Figure 4.2.1. This setpoint was developed as an
' anticipatory trip for loss of feedwater events. The ,
equation used for this setpoint and errors and delay times ;
are also shown on Figure 4.2.1. This trip function is located in the RPS. An output from the RPS will feed the
}
l 4.2.2. Low SG Level AFW Initiate Setpoint l
This is a protective setpoint designed to initiate AFW l following loss of, or insufficient main feedwater flow. l The low range level instrumentation is used to monitor low i level in the steam generators. For setpoints see Table
- 4. 2 -1. .
e.2.3. AFW Control Level Setpoint This is a level control setpoint designed to be automatically selected following initiation of AFW if one l or more reactor coolant pumps are providing forced circulation. The low range level instrumentation is used to monitor steam generator level at this point and to provide signals to the EFIC control system. For setpoints '
see Table 4.2-1.
4.2.4 Natural Circulation Control Levei Setpoint This is a level control setpoint designed to be automatically selected following intiation of AFW if all four reactor coolant pumps have stopped. Twenty (20) feet of steam generator level provides a thermal center in the steam generator at a higher elevation than that of the reactor. Controlling steam generator level at a minimum .
level of approximately 26.4 f eet insures natural I circulation of the reactor coolant system fluid. The wide j range level instrumentation is used to monitor steam j generator level at this point and to provide signals to j the EFIC control system. For setpoint see Table 4.2-1. l AFWTECD0 Page 26 Rev. 2 1
A6'
_s 4.2.5 ECCS Fill Limit Setpoint This is a level control setpoint designed to be manually selected when no RCP's are running following a LOCA. This setpoint will establish a steam generator feedwater level I which will support steam condensation natural l circulation. The wide range level instrumentation is used i I
to monitor steam generator level in this region. For setpoints see Table 4.2-1.
4.2.6 Low Steam Generator Pressure Setpoint This is a pressure setpoint designed to initiate AFW and to automatically isolate the main feedwater lines to the affected steam generator. This setpoint will isolate main feedwater to the affected steam generator only. -Feedwater to the other steam generator will not be isolated. If one or both steam generators are below this setpoint the EFIC system will initiate AFW and terminate MFW to one or both SGs as appropriate. Pressure instrumentation string requirements are given in Appendix B. For setpoint see i Table 4.2-1.
4.2.7 Low SG Pressure Bypass Permissive Setpoint The EFIC shutdown bypass will only work if the steam generator pressure remains below this setpoint. This permissive feature is required by IEEE-279 and NUREG-0737 II.E.1.2. The setpoint must be high enough to allow operators to place the EFIC Channnel in bypass in nomal cooldown sequences prior to reaching the low SG pressure setpoint, but low enough to assure that the system will not be bypassed (will automatically reset) during a normal heatup prior to reaching het shutdown. For setpoint, see Table 4.2-1.
4.2.8 Steam Generator Differential Pressure Setpoint If both SGs are below the low SG pressure setpoint, the differential pressure setpoint will automatically determine, by comparing the difference in steam generator pressures, which steam generator is to be fed with AFW.
Pressure instrumentation string requirements are given in Appendix B. For setpoint see Table 4.2-1.
AFWTECD0 Page 27 Rev. 2
l I
_, s s- ;g 4.2.9 Atmospheric Dump Valve Operating Setpoint l This is a pressure setpoint designed to automatically open the atmospheric dunp valves to relieve steam generator .
I p ressure. This setpoint is higher than ICS setpoint for
- TBV's but is lower than the lowest main steam relief valve lift point and will therefore decrease the frequency of challenges to the relief valves. Pressure instrumentation i string requirements are given in Appendix B. For l
- i setpoints see Table 4.2.1.
5.0 OPERATION The AFW is in standby mode during normal power operation. Manual action will be required to bypass features of the EFIC system during various modes of operation. The system design will pemit bypassing of four EFIC functions when steam generator "A" or "B" pressure is below a pemissive setpoint .of 725 psig. Those functions are steam generator low pressure AFW initiate, all four RC pumps tripped AFW initiate, steam generator low level AFW initiate, and steam generator overfill terminate. All four functions will be capable of being bypassed via a single "EFIC Shutdown Bypass" switch in each channel. The bypass switches are located in the main Control Room on HlSS and in each of the EFIC Cabinets. Eutomatic reset of all four trip functions will occur if they are in bypass and both steam generator "A" and "B" pressures exceed 725 psig. l l
5.1 Heatuo from Cold Shutdown to Hot Standby Before heating up from cold shutdown, the operator should verify the status of the EFIC. All signals should be in bypass.
Shutdown bypassing of the EFIC System is indicated by backlighted i
pushbuttons on the HlSS Console. The reactor power /MFW flow trip
) does not have an explicit bypass. However, this trip will allow l
the plant to go to approximately 20% power with no MFW flow and, I therefore, this trip is effectively bypassed. As heatup progresses the four functions of SG low pressure AFV initiate, all l
four RCP's tripped AFW initiate SG low level AFW initiate, and SG l overfill terminate will automatically reset when both steam generator A and B pressures exceed 725 psig. A manual reset of the shutdown bypass is possible at the EFIC cabinets, regardless of SG pressure.
5.2 Hot Standby to Full Power ]
At hot standby conditions, all trip functions should be active.
No operator actions are required.
Conversely, when reducing power from full power to hot standby, no operator actions are required. Shutdown bypassing is also possible through local switches in the EFIC cabinets.
AFWTECD0 Page 28 Rev. 2 1
5.3 Cooldown from Hot Standby to Cold Shutdown During the cooldown, four EFIC functions must be manually bypassed. These functions are SG low pressure AFW initiate, all four RC pumps tripped AFW initiate, SG low level AFW initiate, and SG overfill terminate. When either steam generator is below 725 psig these functions may be bypassed via a single "EFIC Shutdown Bypass" in each of the four channels. The bypass switches are located in the main Control Room. Action to bypass these function i must be taken before either steam generator pressure reaches 600 psig.
6.0 CASUALTY EVENTS AND RECOVERY PROCEDURES _
6.1 Casualty Events As part of the design of the AFW system, consideration was given to handling the following casualties:
a) Loss of main feedwater (LMFW) b) LMFW w/ loss of offsite AC power c) LMFW w/ loss of onsite and offsite AC power d) Plant cooldown e) Turbine trip with and without bypass f) Main feedline break g) Main steam line break / auxiliary feedwater line break h) Small break LOCA i) Fire outside of Control Room J) Fire in the Control Room 6.2 Desian Features to Mitiaate Effects of Casualty Events 6.2.1 Loss of Main Feewater (LMFW)
Loss Main Feedwater (LMFW) - Upon loss of all feedwater AFW pumps are automatically initiated by the EFIC system.
A valves wide open flow rate of 475 gpm even with a single failure is sufficient to mitigate the effects of LMFW.
ld After initiation, the level will be automatically 4 controlled to about 2 feet. The only required operator actions concerning AFW are to confirm that AFW flow has ,
been initiated and that a level has been established in both OTSG's.
l l AFWTECD0 Page 29 Rev. 2 l
.)
/
C.2.2 Loss of Main Feedwater with Loss of Offsite AC Power -
Upon loss of offsite AC power (which causes.a loss of the RC pumps), the AFW system is used to establish natural circulation. AFW pumps are automatically initiated by the "
EFIC system. The level rate control system will automatically raise the level in the OTSG's to the natural circulation setpoint at a rate of-between 2"/ minute and 8"/ minute. The high auxiliary feedwater injection point in the steam generators provides a high thermal center which will establish natural circulation even with a low steam generator level. For a high decay heat rate event, the level should increase to the natural circulation -
setpoint at 8"/ minute without requiring any operator l action. For lower decay heat rate events, the excess AFW injection will begin to quench the steam, and steam pressure in the OTSG will drop. This decrease in OTSG steam pressure (and saturation temperature) will continue
- to cool the primary system. The EFIC is designed to automatically throttle back AFW flow as steam pressure i drops.
The flow will be throttled to a minimum of about 2"/ minute level increase when steam pressure drops to about 800 psig or below. This feature will minimize the potential for overcooling. For very low decay heat rates, the operator may have to take manual control of the AFW system and further reduce AFW flow to keep from loosing pressurizer level. The design basis for the EFIC is to allow a minimum of 10 minutes with no operator action for all cases. It is anticipated that either no operator action I will be required, or time well in excess of 10 minutes will be available for operator action.
6.2.3 Loss of Main Feedwater with Loss of Onsite and Offsite AC l
Power - This event is not a design basis for the plant, i but the AFW system is designed to supply, as required, up !
to 475 gpm flow with the loss of both onsite and offsite ld ,
AC power. All EFIC controls are powered by battery-backed vital busses as are the AFW control and isolation valves.
The turbine driven train of AFW should start and supply sufficient flow as described in Section 6.2.2. However, single and multiple failures of the AFW system are not taken into consideration.
1 6.2.4 Plant Cooldown - The AFW system is capable of being used to assist in a plant cooldown. The plant, however, was not designed for a normal cooldown using only safety grade systems. The motor-driven AFW pumps can be used with the atmospheric dump valves to cool the plant down to the Decay Heat Removal System cut-in temperature.
6.2.5 Turbine Trip With and Without Turbine Bypass - This event does not affect the AFW system unless MFW fails. In which case, the loss of MFW event in Section 6.2.1 describes the behavior of the AFW system.
AFWTECD0 Page 30 Rev. 2
l 4
Main Feed Line Break - This break is a more abrupt case of l 6.2.6 LOFW and has approximately the same requirements for AFW flow. If the break is upstream of the last feedwater line l check valve, the accident should proceed as the loss of main feedwater event described in 6.2.1. If the break is downstream of the last check valve, the steam generator will blow down to the containment or the tank f arm and AFW will be initiated through EFIC by either a low SG 1evel or l low SG pressure. When the SG has depressurized below approximately 600 psig, the steam generator isolation logic will isolate main feedwater to the affected steam generator. Upon reactor trip the turbine control commands l
the turbine throttle valves to close, thus allowing the unaffected steam generator to repressurize. After isolation of the affected steam generator the EFIC vector logic will supply AFW only to the intact steam generator.
6.2.7 Main Steam Line Break / Auxiliary Feedwater Line Break - The effect on the system from both of these transients is essentially the same. For smaller break sizes, the steam generator will not depressurize or will require a very long time to depressurize. No automatic action is taken for these cases. The operator must diagnose the problem and take appropriate manual actions. For break sizes that will depressurize the steam generator down to approximately 600 psig, EFIC will automatically terminate main feedwater to the depressurized steam generator (s).
Some break sizes and locations may cause both steam generators to depressurize below 600 psig without a 100 psid differential between the two steam generator pressures. In this case main feedwater will be teminated automatically to both steam generators. A reactor / turbine trip signals (via the turbine control) the turbine stop valves to Close. If the break is downstream of the turbine stop valves, both steam generators should repressurize. AFW will then be fed to both steam generators. If the break is upstream of the turbine stop valves, one steam generator will repressurize unless both HV-20560 and HV-20569 are open. The EFIC vector logic will direct AFW only to the intact steam generator or if both are depressurized equally, will feed both.
For a steam line break with a concurrent failure of one turbine stop valve in the unbroken line, the back pressure in the unbroken steam line may prevent the turbine stop valves in the broken lines f rom seating. Both steam generators will blow dry af ter the rupture. Since main feedwater has been isolated, the accident is terminated, and the core does not return to criticality. An equilibrium reactor system cooldown and depressurization is achieved by operator control of the auxiliary feedwater flow with steam relief out of the steam line break.
Refer to Abnomal Transient Operating Guidelines (ATOG) for operator actions required.
Page 31 Rev. 2 AFWTECD0 1
6.2.8 Smalf Break LOCA - For a Small Break LOCA (SBLOCA) event, i
the AFW system will be automatically initiated by an SFAS signal. Current procedure also requires that the RC pumps be tripped for a Small Break LOCA. 'Under these conditions, the EFIC syste should automatically raise level at a controlled rate in the steam generators to the natural circulation setpoint. The time it takes for the controlled rate fill to get level process to the natural circulation setpoint will vary depending on initial SG '
l inventory. During this time, current procedures require that the operator diagnose the event to determine that it is a SBLOCA. When this determination has been made, the operator is instructed to select the ECC level setpoint.
'The purpose of raising the level is to assist in l establishing steam condensation natural circulation if part of the primary system is voided. Prior to reaching the required ECC level setpoint there will be substantial AFW flows high in the OTSG. These flows will provide good heat transfer high in the OTSG.
Selection of the ECC level setpoint will continue the
' filling of the OTSG at a controlled rate.
If filling the OTSG at some rate other than the one used in the EFIC system is required, the operator may take
. manual control of the AFW control valves. AFW can thea be manually controlled as required for a given situation.
6.2.9 OTSG Overfill - A main Feedwater (MFW) overfill event is detected by a high range differential pressure signal.
When an excessive level is detected, main feedwater to the affected steam generator is teminated. Termination of .
MFW will, in most instances, lead to a reactor trip.
Recovery from this condition requires operator action to detemine the causes and restore MFW.
l 6.2.10 Shutdown Initiated by Fire Outside the Control Room - The fire and its location are reported to the main Control i
Room and at the operator's discretion cooldown using auxiliary feedwater may commence. The operator manually initiates auxiliary feedwater via EFIC controls on H1SS.
Automatic level control will be available through EFIC Channel A and/or B. However, one or the other channel may be affected by the fire and require isolation of the control valves using Control Room controls.
6.2.11 Shutdown Initiated by Fire in the Control Room - After evacuation of the Control Room auxiliary feedwater may be controlled from the shutdown panel H2SD in the West Switchgear Room through EFIC Channel A. OTSG pressure control and cooldown rate will be through EFIC Channels A and B for OTSG's A and B respectively. Control Room to Shutdown Panel EFIC control transfer and manual initiation of auxiliary feedwater will be performed locally at the EFIC A and B cabinets located in the NSEB.
Page 32 Rev. 2 ,
AFWTECD0
- 7. 0 TESTING AND MAINTENANCE The AW System is designed to allow periodic testing during power operation. Routine maintenance activit'es, however, should be perfomed during plant outages. The technical s,,vcification will allow one. train of the AW system to be inoperable for only a short period of time during power operation (72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />). Therefore, most corrective l maintenance must be performed with the plant shutdown.
7.1 Periodic Testino of the Fluid System The system design allows testing of the pumps and valves in the AFW system during power operation. The pumps can be tested by manually starting them and flowing through the flow test valw i FY-31855 to the condenser. The AFW isolation valves are closed in the absence of an automatic _ initiation signal. Therefore, no system realignment or bypassing is required to perform this test.
All automatic valves in the AFW system can be full stroke exercised (with the AFW pumps off) during power operation. No system realignment is required to perform these valve tests.
7.2 Periodic Testino of the EFIC The EFIC is designed to be tested from its input teminals to the actuated device controllers. A test of the EFIC trip logic will actuate one of two relays in the controllers. Activation of both relays is required in order to actuate the controllers. The two relays are tested individually to prevent automatic actuation of j the component. Testing of the sensor inputs to the EFIC will t normally be accomplished with the plant at cold shutdown. EFIC j trip testing is discussed in Section 3.4.6.
AFWTECD0 Page 33 Rev. 2
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T Table 3.4-2 Equipment Actuated through the Trip Interface Equipment EFIC lE or flon-lE Channel Control Circuit AFU Initiate (Trio Bus 7)
- 1. AFW Pump, P-319 (start) A lE
?. . AR1 Flow Test Valve HV-31855 (close) A&3 lE FY-31855 (close) A&8 non-lE
- 3. ARJ Pump Steam Inlet Valve B lE FV-30801 (open)
- 5. EFIC AP4 Initiation A&B lE Indication (H2SF)
- 6. Annunciator Window (AFW Initiate) A&B non-lE tiain Steam Line Isolation "A" 0TSG (Trio Bus 8) l - None -
1 Main Feedwater Isolation "A" OTSG (Trio Bus 10) l
- 2. MFW Start-up Control . Valve A lE '
- 3. HV-20d29, Block Vaive (close)
A lE
- 4. MFN Isolation Valve ("A" 0TSG) B' lE HV-20515, (close)
- 5. Annunciator Window (MFW Isolation) A&B non-lE Main Stean Line Isolation "B" OTSG (Trio Bus 9)
- None -
tiain Feedwater Isolation "B" OTSG (Trio Bus 11)
- 2. MFW Start-up Control Valve A lE
("B" 0TSG), FV-20575 (close)
- 3. HV-20530 Block Valve (close) A lE
- 4. tiFW Isolation Valve ("B" OTSG) B lE HV-20515, (close)
- 5. Annunciator Window (MFW Isolation) A&B non-lE AFWTECD0 Page 35 Rev. 2
~1ll6
I l
Taule 4.2-1 AFW SYSTEM SETPOINTS l
ANALYTICAL ANALYTICAL NORMAL f1AXIMUM SETPOINT MINIMUM SETPOINT SETPOINT SETPOINT NORMAL ACCIDENT NORMAL ACCIDENT Low SG Level Initiate 13.5" 16.5" N/A 9" N/A -
AFW Control Level 27.5" --
44.5" --- 9" Natural Circulation Control Level 31 7 " ---
388" --- 240" SG Overfill Setpoint 619" ---- --- --- ---
EFIC Shutdown Bypass Pennissive 725 psig N/A ---
N/A ,
ECCS Fill Limit 381" N/A 420.f" N/A 336" l
Low Steam Generator
! Pressure 600 psig 625 psig N/A* 575 psig N/A*
Steam Generator Differential Pressure 100 psid 150 psid N/A* 50 psid N/A*
ADV Control 1020 psig N/A N/A Setpoint
- The steam generator prer,ure measurements will be located outside the reactor building and protected from temperature excursions so accident environment errors do not apply.
All level setpoints refer to the equivalent height of a saturated water column referenced from the top of the lower tube sheet. It should be i noted that the lowest low range instrument sensing tap is at an '
elevation of 6" above top of lower tube sheet.
AFWTEC00 Page 36 Rev. 2
w .
Figure 4.2.1 Flux to Feedwater Setpoint The following is the eqaation for the nominal setpoint used in Figure 4.2-1.
Flux = 1.9 MFW + 21 where: MFW = total main feedwater flowrate in % of total flow Flux = neutron flux measured in % full power The errors and delay time used in developing this setpoint are:
Flow measurement error = 5.5%
Flux measurement error = 6.0%
Delay time = 2 sec. (max.)
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o APPENDIX A List of ficures which fom a part of this document TITLE NUMBER 3.1 -1 Cycle 8 Auxiliary Feedwater System (2 Sheets)
- 3. 4-1 EFIC Organization 3.4-2 EFIC Control Logic i 3.4-3a EFIC Steam Generator "A" Input Logic 3.4-3b EFIC Steam Generator "B" Input Logic 3.4-3c EFIC Steam Generator Pressure Input Logic 3.4-4 EFIC Initiate Logic 3.4-5 EFIC Trip Logic 3.4-6 EFIC Vector Logic 3.4-7 EFIC Test' Philosophy 3.4-8 EFIC Symbology
' Page 38 Rev. 2 AFWTECD0 I6
t s .
APPENDIX B l
INSTRUMENTATION REQUIREMENTS I l
The instrumentation requirements listed below are capatible with the systems f analysis and setpoints performed under B&W document 32-1155738.
Instrumentation environments listed in the Secondary Notes are valid for those I specific transmitters which provide sensor inputs to EFIC.
- 1. Low Range Level Instrument String I a. Tap Elevations 6" & 156"
- b. Pressure 1200 psig
- c. Tempe uture 600 F
- d. Instrument String Errors:
e.1 Nonnal Operating Environment +3" (trip)/+3.2" (control)
-4.5" -4.6" i
+17" e.2 Design Break Environment -18.5" (trip)/+3.2" (control) l
-4.6 j See Notes 1, 2 and 3 *See also Secondary Notes t., b and c.
- 2. Wide Ranae Level Instrument String
- a. Tap Elevations 6" & 61 9"
- b. Pressure 1200 psig
- c. Temperature 600 F
- d. Instrument String Errors:
e.1 Normal Operating Environment +12.5" (trip)/+15. 5" (control)
-18" -21.5" !
)
e.2 Small LOCA Environment
+39.5" (trip)/+15.5" (control)
-45" -21. 5 "
e.3 Design Break Environment +71" (trip)/+15.5" (control)
-77" -21. 5" See Notes 1, 2 and 3, Also Secondary Notes a, b, and c
- 3. Pressure Instrument Strings
- a. Span 0-1200 psig
- b. Response Time 1 second
- c. Instrument String Errors:
c.1 Normal Operating Environment +/-25 psi Page 39 Rev. 2 AFWTECD0 h
. y .l
. i NOTES:
- 1. Level measurement to be density / pressure compensated over a pressure l range of atmospheric to 1050 psig assuming a saturated volume of steam and water. Since the level measurement is density compensated, the unit
" inches" refers to the actual level in the steam generator over the i l
specified pressure range.
- 2. String errors include a -1.4" and 5.72" reference leg heatup error for the low range and wide range, respectively.
l l
- 3. During power operation, flow rates through the steam generator can be l considerable. The differential pressure transmitter readings feeding EFIC or other systems can therefore be altered considerably due to flow related pressure drop and lack of a definitive steam / water interf ace.
" Level" as read by EFIC or other systems, during power operation, is related to inventory or liquid in the steam generator, but the l
quantitative relationship is complex and varies with generator fouling. f l j For very low power operation, (less than about 5% power), and for steam )
flows typical of past reactor trip, the " Level" as indicated by EFIC is I the real liquid level (in inches) above the lower tube sheet.
Secondary Notes:
- a. Normal Operating Environment 80F to 140F/100%RH
- b. Small LOCA Environment 80F to 240F/100%RH Radiation Dose Air (TID Rads) - 2 Hours = 1.86 x 10 (includes 40 yr. service 36 Hours = 6.0 x 10 dose of 10 RADS) 30 Days = 9.2 x 10 Peak Building Pressure 43 psia 0 2500 seconds after accident l
- c. Design Break Environment Building Pressure - 1 min. - 60 psia Temperature - 3 min. - 320F 2 min. 69 psia 6 min. - 300F 2 hrs. 18 psia l 30 min. - 275F 2 weeks - 18 psia i 1 hr. - 200F I week - 190F Humidity - 100%
Radiation Dose Air (TID RADS) - 3.4 x 10 (includes 40 yr service dose of 10 RADS) soilding Spray pH - 7.5 to 10 Page 40 Rev. 2 AFWTECD0 7b
_j s 23 A t.PPEhuiX C REY. 1 ATTACHMENT TO i l
l EFIC SYSTEM DESCRIPTION l
i k
Subject:
EFIC Electrical Cabling Separation Requirements 1
l The EFIC System uses a four (4) channel input scheme for it's " initiation" logic, but is a two channel " actuation" and " control" logic scheme. Thus, if EFIC is gathering inputs which it will combine logically to automatically
)
initiate AFW or isolate MFW then it will require four channel input. However l
once it has made a decision, or if it is told to do something by another logic system (e.g. Control Room Operator, or SFAS) it will carry out the function with two channels of actuation and/or control. Basically the scheme is, in this regard, just like the RPS and SFAS, all three require four channels of
" inputs" but only " actuate" two output channels. However, we know that SFAS differs from RPS in the details of how this is done, and EFIC also differs from both RPS and SFAS in the details of how it combines logic and carries out i
commands.
AFWTECD0 Page 41 Rev. 2
y In order to detemine the separation and protection criteria for the cabling to be installed as a part of Mod 001, the desired functions were A matrix was developed ]
compared to the required number of redundancies.
1 showing channel separation required to assure sufficient redundancy for each type of cable in each sub-ECN. It shows the required redundancies for each of the accidents being protected against. The matrix reflects the necessity to preserve automatic initiation of AFW for those HELB and missile scenarios which directly cause or result from loss of main feedwater and/or loss of steam generator pressure. Appendix "R" scenarios allow manual initiation of EFIC functions from the Control Room for fires outside the Control Room, and manual initiation of EFIC functions from EFIC cabinet "A" for events requiring evacuation of the Control Room. This is consistent with rules developed for current Appendix "R" procedures and 10CFR50, Appendix R, IIIG and IIIL.
The separation requirements shown are sufficient to assure safe operation in all assumed accidents. However, instances may arise in which the
" separation fomula" may not be possible without extreme measures being l taken. Relief from the separation fomula may be possible for the l
specific instances. For instance, full four channel protection is not j
required for a break of the Decay Heat line inside containment. This is !
because the safety function for automatically starting the AFW system for i a LOCA is via the SFAS to EFIC. Exceptions from the separation fomula should be dealt with on a case by case basis.
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Electrical Separation Appendix R j (Separate wireways) HELBA/ Missile Fire Separation i Sub ECN .
A,B,C,D A,B,C,D A, B 5415B 5415C A,B,C,D AC, BD Pressure Signal A,B,C,D N/A N/A Freeze Protection A, B l
5415D A, B N/A N/.A In Control Room A,B,C,D A,B,C,D A, B Control Room to EFIC MFW Flow X-mitters to RPS A,B,C,D See 0737 II.K.2.10 N/A (Attached)
A,B,C,D N/A N/A RPS to MUX 5415E A,B,C,D A,B,C,D A, B Power A,B,C,D A, B A, B EFIC to Mux A, B A, B A, B EFIC to TIE 5415F A, B N/A N/A In Control Room A, 8 A, B A, B !
Control Room to EFIC 1
A, B A, B A, B 5415G A,B,C,D A, B, C, D A, B 5415L A, B A, B A, B 5415M Page 43 Rev. 2 AFWTECD0
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Electrical Separation Appendix R (Separate wirewasy) HELBA/ Missile Fire Separation Sub ECH A, 8 A, B A, B 5415N 5415P A, B A, B A, B EFIC to transfer switch Transfer switch N/A N/A to shutdown panel N/A 5415Q A, B A, B A, B Signal Cable A, 8 N/A N/A, Freeze Protection 3
A, B, C, D, Non-1E N/A N/A 5415R A, B, C, D, Non-1E A,B,C,D A, 8 54155 l
5415T TIE to FV-31855 A, B A, B N/A A,B,C,D AC, BD AC, BD 5415U A, B A, B A, B 5415V A,B,C,D AC, BD AC, BD 5415W 5415X A,B,C,D AC, BD AC, BD )
a A, B A, B A, B t
5415Y 54152 A, B A, B A, 8 AFWTECD0 Page 44 Rev. 2 i
Electrical Separation Appendix R (Separate wireways) HELBA/ Missile Fire Separation Sub ECN A,B,C,D AC, BD AC, BD 5415AA
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- A, B A, B A, B 5415AB A, B A, B A, B 5415AC A, B A, B A,- B 5415AD A, 8 A, B A, B 5415AE' 4
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1 AFWTECD0 Page 45 Rev. 2-lW
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APPENDIX D DIGITAL STATUS SIGNALS FROM EFIC AND AUXILIARY FEEDWATER SYSTEM The following is a list of those outputs from either the EFIC or the AFW system which will be provided to the IDADS. The " DESCRIPTION" is the actual 32 character desetiption assigned to the signal which will be The " ALM LOG" indicates whether the parameter is to displayed by)IDADS.be logged (L , alarmed and logged (AL), or only available for status (S). Ant. log signals are indicated by the word " Analog" in the " ALM LOG" column.
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