ML20054F759
| ML20054F759 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 06/11/1982 |
| From: | Dale L MISSISSIPPI POWER & LIGHT CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0831, RTR-NUREG-831 AECM-82-261, NUDOCS 8206170295 | |
| Download: ML20054F759 (31) | |
Text
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l M MISSISSIPPI POWER & LIGH Helping Build Mississippi P. O. B OX 164 0, J AC K S O N, MIS SIS SIP PI 3 9 2 0 5 June 11,1982 NUCLEAR pro 00CTioN DEPARTMENT U. S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, D. C. 20555 Attention: Mr. Harold R. Denton, Director
Dear Mr. Denton:
SUBJECT:
Grand Gulf Nuclear Station Units 1 and 2 Docket Nos. 50-416 and 50-417 File: 0260/0840/L-350.0 Transmittal of Evaluation for Control Systems Failures; SER License Condition Item 1.11(10)
AECM-82/261 Mississippi Power & Light (MP&L) letter, AECM-82/159, dated April 22, 1982, transmitted information in regard to Safety Evaluation Report (SER),
NUREG-0831 License Condition 1.11(10). It was noted in the report that certain reviews / verifications were required and that a final report would be forthcccing. The attachment to this letter represents our final report and
, therefore, supercedes Attachment I to AECM-82/159.
If you have any questions or require further information, please contact this office.
s truly, M
L. F. Dale Manager of Nuclear Services JTB/JGC/JDR:lg
Attachment:
- 1. Control Systems Failure Evaluation cc: (See Next Page) o\
o 8206170295 820611 PDR ADOCK 05000416 E PDR Member Middle South Utilities System
MISSISSIPPI POWER O LIE HT COMPANY cc: Mr. N. L. Stampley Mr. R. B. McGehee Mr. T. B. Conner Mr. G. B. Taylor Mr. Richard C. DeYoung, Director Office of Inspection & Enforcement U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Mr. J. P. O'Reilly, Regional Administrator Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Region II 101 Marietta St., N.W., Suite 3100 Atlanta, Georgia 30303
- E MISSISSIPPI POWER Q L12HT COMPANY bec: Dr. D. C. Gibbs (w/o)
Mr. A. Zaccaria (w/o)
Mr. L. E. Ruhland (w/o)
Mr. R. S. Trickovic (w/a)
Mr. C. D. Wood (w/o)
Mr. J. F. Hudson, Jr. (w/o)
Mr. T. H. Cloninger (w/o)
Mr. J. P. McGaughy (w/o)
Mr. T. E. Reaves (w/o)
Mr. C. K. McCoy (w/o)
Mr. J. W. Yelverton (w/o)
Mr. A. R. Smith (w/o)
Mr. R. F. Phares (w/a)
Mr. A. G. Wagner (w/a)
Mr. C. C. Hayes (w/o)
Mr. M. D. Houston (w/a)
Mr. J. F. Pinto (w/o)
Mr. M. D. Archdeacon (w/a)
File (w/a) l l
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CONTROL SYSTEMS FAILURES EVALUATION The evaluation discussed in this attachment was performed in response to the NRC letter dated April 16, 1981 (MAEC-82/80), from R. L. Tedesco to J. P. McGaughy.
A. Common Power Supplies Methodology This evaluation covers the spectrum of all non-safety control systems whose failures (resulting from the loss of common power supplies) could have the potential to cause the consequences of transients or accidents evaluated in FSAR Chapter 15 analysis to be more severe.
The evaluation was developed in accordance with the steps described below:
- 1. A review of FSAR Chapter 15 events was conducted and a list of non-safety control systems was developed whose failure could have the potential to impact reactor pressure, reactor water level or reactor power. The list consisted of the following.
non' safety control systems:
- a. Reactor Feedwater System
- b. Reactor Turbine Pressure Regulator System
- c. Recirculation Flow Control System
- d. Feedwater Heater System (Condensate and Extraction Steam)
- e. Condenser. Vacuum System
- f. Reactor Water Level 8 Turbine Trip
- g. Bypass System Operation
- h. Rod Control and Information System (RC&IS)
- i. Environmental Control System (Offgas Vent and Offgas Flow Control System)
- j. Instrument Air System (Isolation Actuation) i Master Parts List (MPL) system number prefixes associated with l
the above non-safety control systems:
B33, C11, C34, C85, D17, N19, N21, N23, N31, N32, N33, N34, i N35, N36, N43, N62, N64, PS2, P53
- 2. This step provided the data base necessary to identify the potential control systems and electrical loads which were to be considered for this analysis. In preparing data for a i response to IE Bulletin 79-27 (letter submittal AECM-82/121, dated April 29, 1982), a complete set of tables were developed which included all electrical loads of power generation design basis systems. Each electrical load listed in the tables was identified by its unique MPL system number, circuit description, power distribution (lowest to highest level power source) and effects (primary and secondary) due to power loss.
If the actual effect for each power loss evaluated could not I be determined, the effect was delineated by a worst case assumption. For example, an actual effect would be a pump trip resulting from loss of power. However, if the loss of power caused a fail-as-is condition to a throttle valve, a worst case assumption would have to be made since the position of the valve prior to the power loss would be undetermined.
An example of these tables is provided on Attachment No. I to this report.
MIDI
+
i CONTROL SYSTEMS FAILURES EVALUATION - Ccatinu:d
- 3. All supporting electrical components'or loads having the same !
MPL tystem number prefix as the ten non-safety systems defined i in Step 1 were identified utilizing the drawings referenced in )
Step 2.
~
1
- 4. After identifying all components, a list of elimination criterion was established which provided a basis for
' determining whether an individual component would require further consideration or could be deleted from the analysis.
Each of the original loads identified.on the. drawings (Step 3) were reviewed against each of the criteria listed below. .A component which met any one of the following criteria was eliminated from consideration and the applicable elimination code (NI, N2, etc.) was indicated on the associated drawing next to the component's MPL system prefix. (Examples of loads eliminated are indicated on Attachment No. 1.)
Elimination Elimination Criterion Code
- Criterion N1 Components whose failure effects are '
clearly bounded by a dominant failure effect on the same breaker can be eliminated by inspection. For example, the loss of several trips such as feedwater turbine overspeed trip on the same breaker as the solenoid that controls all remote trips. The solenoid loss is clearly the dominant effect. Also, in the case of identical components, only one of the components on that breaker need be listed. However, when it was not obvious by inspection that a component could be eliminated by this criteria, it was included for further analysis.
N2 Instrumentation which have no direct or indirect controlling function or passive input (such as permissive) into control logic. Instrumentation and other dedicated inputs to the process computer, as well as the computer itself, can be excluded. Operator actions as a result of indications are not considered control functions for the control systems failure analysis.
N3 Control systems and controlled components (heaters, fans) which have no direct or indirect interaction with reactor operation or reactor parameters. For example, communications, most unit heaters and controls, lighting controls and ventilation control systems for exterior buiidings.
MID2
CONTROL SYSTEMS FAILURES EVALUATION - Ccntinu:d Elimination Elimination Criterion Code
- Criterion N4 Control systems and controlled components (pumps, valves) that do interact or interface with reactor operating systems but which cannot affect the reactor parameters (water level, pressure or reactivity) either directly or indirectly.
For example, some offgas components and area radiation monitors.
N5 Systems which are not used during normal power operation. For example, start-up, shutdown or refueling systems not used.
during normal operation.
N6 Some lube oil pumps are powered from AC busses but have a back-up pump powered from a DC source. Since a single electrical failure cannot disable the lube oil function these components were eliminated from the analysis.
Y Required further analysis and therefore, were not eliminated.
- In some cases more than one of these criteria may apply.
- 5. Bus tree tables were then developed for all components requiring further analysis, utilizing the power distribution and other information described in Step 2. The bus tree tables were primarily developed in order to group all components according to their common bus structures thus, establishing a format to evaluate all potential combinations of electrical load failures that could occur as a result of a single bus failure. Bus tree development was limited to certain pre-selected high leval busses in the power distribution system (See FSAR 8.1-1). The evaluation of loss of power supply was taken no higher than these pre-selected busses because the loss of the next higher level bus (bus 12R) initiates an event that is already bounded by loss of AC power evaluations presented in FSAR Chapter 15.2.6.
- 6. The above process resulted in a bus tree table consisting of those control systems remaining common at some power level and whose individual failures were shown to have a potential effect (see Attachment No. 2 columns labled " Primary Effect" and "Second(y Effect") on one or more reactor parameters.
Further analysis was performed to determine the combinational effects of multiple control systems failures where applicable due to the loss of a lowest common level power source (See Attachmert No. 2 column labled "Combinational Effects").
MID3
1 CONTROL SYSTEMS FAILURES EVALUATION - Continuzd ;
- 7. Further analysis was performed to determine the most severe bus failures and their combinational effects resulting from ,
the effects of cascading power losses extending from lowest- !
common level power sources to higher level distribution. j panels, battery busses, and load centers. This task was '
accomplished by. utilizing the combined effects at the lowest common level bus (Attachment No.' 2) as a starting point. The next higher common level bus was then postulated to. fail and the total effects at that level were analyzed. This method was repeated for each higher level bus; continuing the process up to the highest level bus.in the bus tree tables. For power -
losses where competing effects existed, the dominant failure effect was determined by an evaluation of the circuitry involved or a worst case assumption was made. An example of two competing effects resulting from the same bus loss, would be the generation of a trip signal to a pump's trip solenoid initiating a pump trip, in conjunction with the deenergization ;
of the same trip solenoid resulting in the loss of the trip function. By evaluation, the dominant effect for the above case was determined to be the loss of the trip function. If-it was not possible to determine the dominant effect, worst case assumptions were made considering all cases involved.
Attachment No. 3 delineates the highest level busses and shows the most severe bus failures and their combinational effects resulting from the effects of cascading power losses.
- 8. The most severe combinational effects resulting from power-losses were then analyzed against specific events in FSAR Chapter 15 (Attachment No. 3). The evaluation revealed no )
power supply failure which initiated an event not bounded by i the current transient analysis presented in FSAR Chapter 15.
B. Common Instrument Line Methodology This evaluation covers the spectrum of all non-safety control systems whose failure (resulting from the loss of common instrument lines) could I have the potential to cause the consequences of transients or accidents evaluated in FSAR Chapter 15 analysis to be more severe.
The common instrument line failure analysis was performed after the common bus failure analysis was completed. The methodology used was as follows:
- 1. A list of instruments was developed that provided inputs to the non-safety control systems identified in Step 1 above and which also shared a common instrument line with another instrument.
- 2. The effect of the loss of these instruments was listed in terms of the systems or components affected.
- 3. Instrument combinations whose loss had been covered previously in the electrical portion of-the control systems failure analysis were eliminated.
MID4 1
f CONTROL SYSTEMS FAILURES EVALUATION - Continu;d
- 4. The remaining instruments were then grouped according to their common taps and evaluated for the case of a broken line or plugged line (Attachment No. 4). In the case of absolute ,
pressure instruments, the plugging mechanism was assumed to cause an increase in pressure since this would cause the worst case effects.
- 5. The effects on the reactor parameters resulting from the loss of common instruments were then analyzed against events in
-FSAR Chapter 15 (Attachment No. 4). The evaluation revealed no common instrument failure which initiated an event not bounded by the current transient analysis presented in FSAR Chapter 15.
MID5
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IEB 79-27 S YS. COMF0n E ET PRIVARY SECOEDARY COM014AT10hAL -
TABLEkm. hD. DESCRIPTION EFFECT EFFECT EFFECTS
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g i BATTE RY BUS 1501-5 B33 RECIRC PUMP MOTOR A LOSS OF TRIP CIRCUIT LOSSOF AUTOPROTECT 11DA {1DA1 .
CLASS IE BREAKER 2521205C SERVICifvG i TRIP CIRCUIT FOR BREAKER 252-1202 REMOTE TRIP CAPABILIT'r THE SAME MOTOR IN SERIES IS AVAILA8LE TO S l NO EFFECT
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l10A2 1501-22 B33 RECIRC PUMP MOTOR B LOSS OF TRIP CIRCUlT LOSS OF AUTO PROTECT CLASS 1E BREAKER SERVICING THE SAME I TRIP CIRC
- LIT FOR BREAKER 25211038 REMOTE TRIP CAPABILIT'r MOTOR IN SE RIES IS AVAILABLE TO TRIP. .'
l NO EFFECT*
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BATTERY BUS 1502-3 B33 RECIRC PUMP A & B MOTOR RECIRC PUMP A & B FAIL CLOSED. NO EFFEC r NO EFFECT AT NORMAL POWER OPERATIOpL 1108 11081 BREAKER BREAKER Fall AS IS Fall OPEN . LFMG ONLY *
' d POWER SOURCE;LIMITINC l PUMP TO 25% OF MAX
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- NO EFFECT AS USED IN THESE EVAL JATI(livS MEANS NO SIGNIFICANT C)NTRIBUTION TO AN EFFECTON SAF ETY OUTSIDE THE BOUNDS OF rHE FSAR CHAPTER 15 ANALYSIS,
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.s IEB 79-27 SYS. COMPO4EET PRIMARY SE C040 ARY CBettitAit0tAL (
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f LOSS OF FEEDWATER LOSS OF BUS UNLIKELY $1NCE INVERTER WHICH BATTERY BUS 1504-6 N23 BOP PROCESS INSTRUMENTS LOSSOF POWER TO BOP ,
11DD PROCESS INSTRUMENTS AND CONDENSATE FEEDSIT IS BACKEDUPBY AN ALTERNATE AC CONTROL SOURCE AND AUTO-TR.*NSFER LOSS OF THIS BUS CANNOT CASCADE INTO FAILURE OF 1Y74 i
LOSS OF FEEDWATER AND CONDENSATE ALT.AC i -
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PAGE 3 OF 17 Attachment 2 Cemon Bus Tree Te1c J
SYS Co W0 LENT PRiv AR Y SEE0hDARY COU34ATactAt IL479 27 EfIECTS T ABLE NO. h D. DESCRIFY104 ElFECT EfFECT BATTERY BUS l504 29 t421 RFPT A DISCHARGE LOSS OF RFPT A LOSS OF AUTO CAPA- LOSS OF REMOTE ABILITY TO TRIP RFPT A.
11DD T RIP DISCHARGE TRIP ABILITY TO TRIP RF PT PARTIAL LOSS OF FEEDW ATER HE ATING.
PUMPS C004A & C004B ON DISCH ARGE PHESSURE THE LOSS OF REMOTE MANUAL CAPABILITY
" k F421 RFPT A TRIP ON LOSS OF RFPT A LOSS OF AUTO ABILtTV ON REACTOR WATER LEVEL.
LOW RECIRC FLOW OR T RIP RELAY TO TRIP ON RECIRC LOW LOW SUCTION .RFPT 8 TRIP ON BUS 11 DE) F LOW OR LOW SUCTION PR ESSUR E PRESSUR E 1504 30 r436 EXT R ACTION STE AM I AILS CLOSED INLETS TO FLOW SYSTEM SOLENOID HE ATERS SA & 6A VALVE SVF 525A CLOSE D. LOSS OF DD2 HE AIER STRING, RATED g
FW FLOW REDUCED TO .
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95%.
i 1504 32 'J21 RFPT A TRIP ;VF 612A OE ENE RGl2ED LOSS OF REMOTE CAPA-SOLENOID SVF 612A (T RIP B SOLENOID ON BILITY TO TRIP RFPT A-llUS 11DE) 1504 32 'J21 RFPT A SPEED LOSS OF SPEED LOSSOF REMOTE
, CHANGER CONTROL CHANGE R CONTROL MANUAL CAPABILITY lRFPT B ON BUS 11DE) TO CH ANGE SPE ED.
1504-33 (133 RECIRC PUMP BKR 3A F AILS AS IS NONE BREAKE R 3A CONTROL ICLASS 1E BKR l$ BACK.UP) ,
ll33 RECIRC PUMP BKR 4A FAILS AS IS NONE BREAKER 4A CONTROL ICLASS 1E BKR IS BACK-UP) e S
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4 -y IES 79-27 sys. Cowattti PRIMARY stC0tDARY COMf14AT104AL l
- 40. DESCRIPflot EffECT iffECT tifECTS TABLE hD.
i , THE LOSS OF REL*CTE MANUAL CAPABILITY TO BATTE RY BUS 1504-49 N21 RFPT A SPEED CHANGER LOSS OF SPEED CHANGER LOSS OF REMOTE MAMJAL CAPABILITY TO CHANGE CHA,4GE SPEED OF RFPT A HAS NO EFFECT ON . 's 1100 CONTROL CONTROL REACTOR WATER LEVEL. -'
1 (RFPT B ON BUS 11 DE) SPEED OF RFPT A. O I
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POSStBLE MAIN TURBtNE TRIP. t 1504-50 N35 MOISTURE SEPAR ATOR LOSS OF DRAIN CONTROL POSSIBLE WATER INDUC-l REHEATER VENTS & DRAIN. TION AND/OR OVER
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SPEED TRIP OF MAIN TURBINE. ~ f, s 4 l1DD1 N35 MOISTUR E SEPAR ATOR LOSS OF LEVEL INPUT LOSS OF DIV. "A" CON-
! REHEATER DRAIN LEVEL CONTROLi. TACTS TO TRIP TURBINE j"
AND ALARMS ON H1-HI LEVEL ,
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(DIV."B" B ACK-UP) _i 1504-54 C34 REACTOR HIGH WATER HICH WATER LEVEL StGNAL RX HI LEVEL TRIP "C" LEVEL TRIP *C" 'T" GENE RATED OCCURS (2 OF 3 RE-(TRIP "A" ON BUS 1100) ,
OulRED TO TRIP RFPT'S ,
(TRIP ~8"ON BUS 11DE) NO EFFECT) s j
833 RECIRC PROTECTIVE RELAY LOSS OF PROTECTIVE NONE
. LOGICS "A" R E LAY LOGICS "A"
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~l4 IEB 79-27 sys. COMPontNT PRIMARY SECONDARY COMBilliAfl0NAL TAptt ho. h D. Ot$C RIPTf 04 EffICT EFFECT EFFECTS BATTERY BUS [ 1505 12 N21 RFPT B TRIP SOLENOID SOLENOID DE-ENERG12ED LOSS OF REMOTE CAPA. THE LOSS OF REMOTE MANUAL CAPABILITY TO 11 DE SVF-6128 (RFPT A TRIP SOLENOID ON ABILITY TO TRIP RFPT B CHANGE SPEED OF RFPT B HAS NO EFFECT ON% f BUS 11DD) REACTOR WATER LEVEL. 'i
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150513 N21 RFPT B SPEED CHANGER LOSS OF SPEED CHANGER LOSS OF REMOTE MAN- l 1DE2 I CONTROL CONTROL (RFPT A ON UAL CAPABILITY TO l BUS 11 DD) CHANGE SPEED OF l h RFPT B.
- l 150518 N21 RFTP B TRIP & ALARMS LOSSOF TRIP & ALARMS LOSS OF ABILITY TO TR P
i 150516 N32 TURBINE TRIP SYSTEM LOSS OF TRIP SYSTEM LOSS OF LOW VACUUM PARTIAL LOSS OF CAPABILITY'TO TRIP MAIN .
POWER SUPPLY T RIP. TURBINE THRUST TURBINE BEARING TRIP. LOW AUTOMATIC PROTECTIVE CAPABILITY TO TRIP LUBE OIL PRESS TRIP MAIN TURBINE NOT AFFECTED.
B ATTE RY BUS 50522 N21 RFPT B CONTROLLER LOSS OF RFPT B CON- LOSSOF REMOTE AUTO LOSS OF BUS UNLIKE LY SINCE INVE RTER WHKH TROL (RFPT A ON CONTROL OF RFPT B. F EEDS IT IS BACKED UP BY AN ALTERNATE AC i BUS 1100) .
SOURCE. l AC ! 1505-25 B33 RECIRC LOOP"B" FLOW LOSS OF LOOP "B" FLOW NONE ALT. CONTROL CONTROL (LOOP A ON BUS 11 DD) LOSS OF REACTOR nECIRC LOOP"B* FLOW
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CONTROL l B33 HPU CONTROL CIRCUITS SHUTDOWN OF LOOP"B WITH THE LOSS OF RFPT B REMOTE AUTO
! DIVISION "B" LOSS OF DIV "B" HPU CON-l CONTROL. MAINTENANCE OF NORMAL REACTOR
- INV TROL CIRCUlTS DIV. *A" TAKES OVE R 1YR7 WATER LEVEL IS LIMITED TO THE CAPACITY OF (DIV "A"ON BUS 11 DD) (BUS IS INVERTER FED THE REMAINING RFPT WORST CASE LOSS OF TO.
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TAL FEEDWATER CONTROL OF REMAINING RFPT IS IN MANUAL MODE. .
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i I IEB 79-27 SYS. COMPONENT PRIMARY SECONDPRY COMetNAT104AL ]
TABLEkO. h0. DESCRIPTION EFFECT IFF E C) EFFECTS ;
?.
r C34 REACTOR HIGH WATER HIGH WATER LEVEL SIGNAL Hf LEVELTRIP"B" THE LOSS OF REMOTE MANUAL CAPA81LITY TO '(
BATTERY BUS 1505 32 - .j LEV E L T RIP "B" "B" GENER AT ED OCCURS (2 OF 3 RE. CHANGE SPEED OF RFPT B HAS NO EFFECT ON 11 DE (TRIP "A" ON BUS 11DD) OUIRED TO TRIP RFPT*S REACTOR WATER LEVEL. j 1DE3 M (TRIP *C" ON BUS 11DD) NO EFFECT) ,
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g 1505-33 N21 RFPT B SPEED ' LOSS OF RFPT B LOSS OF REMOTE If BUS CHANGER CONTROL SPEEDCHANGER CONTROL MANUAL CAPABILITY (RFPT AON BUS 11 DD) TO CHANGE SPEED. l4 h i t
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IEB 79-27 SYS- COMPO4ENT FRlMARY SE C040 ARY COM6144flotAL hD. DESCRIPTION EffECT EFFECT EFFECTS TABLE kD.
w BATTERY BUS
( 1508-1 EHC CABINET TURBINE LOSS OF POWER BATTERY BACK-UP . SEE AC BUS 13AD AND SEE BATTERY BUS 11 DJ : 5 11 DH CONTROL NO EFFECT FOR BACK.UP -
CHANNE L 1 STEAM LOSS OF POWE R e j
.'A PRESSURE CONTROL ., 'i CHANNEL 2 STEAM LOSS OF POWER
- PRESSURE CONTROL
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CHANNE L 3 STE AM LOSS OF POWER PRESSURE CONTROL } ,
0 AUXtLIARIES STE AM LOSS OF POWE R PRESSURE CONTROL STRESS / SPEED MEASURING LOSS OF POWER rr UNIT -
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.s IEB 79-27 SYS ED WONENT PRIMARY SEEDEDARY E0 Mil 4&TIStAE . 1 T ABLE NO. 40. DESCR& TION EFFEET EFFEET EF F E ETS I
BATTERY BUS 15091 N32 EHC CABINET TURGINE LOSS OF POWER BATTERY BACK-UP- SEE AC BUS 13AD AND SEE BATTERY SUS 11 DH i 11 OJ 1509 2 TUR81NE CONTROL NO EFFECT FOR BACK-UP CHANNE L 1 STE AM LOSSOF POWk8 PRESSURE CONTROL t
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CHANNE L 2 STEAM LOSS OF POWER f PRESSURE CONTROL c 1 r CHANNEL 3 STE AM LOSSOF POWER PRESSURE CONTROL i s
I AUXILIARIES STEAM LOSS OF POWE R !
PRESSURE CONTROL I STRESS /SPEEO MEASURING LOSS OF POWER
( UNIT
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AC BUS 1201-2
- B33 REACTOR RECIRC SYSTEM PUMP A INOPERATIVE PLANT POWER LEVEL IS PLANT POWE R LEVEL IS LIMITED RECIRC PUMP A MOTOR AT FULL SPEED LIMITED 11 HDlc POWE R CIRCulT (PUMP B ON BUS 12 HE)
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l t IES 79-27 $Y$. COMPONENT PRIMARY SE COND ARY COM5thAT104AL TABLE NO. 40. DESCRIPTION EFFECT EFFECT EFFECTS IfH 12BM 1121-4 N23 MOV HEATER DRAIN PUMP B MOV FAILS F.C.: ORAIN PUMP B OUT NO EFFECT UNLESS FEEDWATER FLOW DEMANO DISCHARGE OF SERVICE. DRAIN INCREASES, 1[BE1 PUMP A AVAIL l N23 MOV HEATER DRAIN PL'MP B F.C.: DRAIN PUMP B OUT l OF SERVICE. DRAIN l SUCTION ,
! g PUMP A AVAIL. j
! 1121 4 N19 MOV CONDENSATE PUMP I AILS AS IS F.C.: LOSS OF CONDEN.
I F C SUCTION SATE PUMP C I
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l FAILS AS IS F.C.: LOSS OF CONDEN-N19 MOV CONDEl4 SATE PUMP
! B SUCTION SATE PUMP B .
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l N19 MOV CONDENSATE PUMP FAILS AS IS F.C.: LOSS OF CONDEN- "f l 12B12 B DISCHARGE SATE PUMP B g -
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N 1122 3 N23 FEEDWATER HEATERS FAIL ASIS (CLOSED) DUMP VALVE WILL M AIN PARTIAL LOSS CF FEEDWATER HEATING g l*g g 30,3C,4B & AC LEVEL l TAIN LFVEL HEATER 3
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, l 8 CONTROL VALVES MAY LOSE EFFICIENCY' s A r
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- IEB 79-27 SYS. COMP 0 TENT PRIMARY SEf0hDARY ', COM86EATIDtAL .
TABLE hD. 40. DESCRIPTION EFFECT E_f F ECT EtfECTS g
.x s 12 HE { 1125-1 N19 CONDENSATE BOOSTER F All AS IS
\
PUMP C OUT OF LOSS OF CONDENSER VACUUM AND TURBINE .$
PUMP "C" DISCHARGE MOV SE RVICE TRIP AFTER TWO MINUTES - WORSE CASE
. , ., j 1125-4 N62 MOV, CONDENCE R OUTLET F ALLS AS IS PUMP B OUT OF '
1}BE4l12841 MOV STE AM SUPPLY Fall AS IS WORSE CASE 'IS LOSS OF 1'
! l L MOV FIRST STAGE SJAE Fall AS IS s. CONDENSER VACUUM .~
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-l g' "B" SUCTION AND TURBlNE TRIP "A" f l Fall AS IS AFTER TWO M*NUTES , {
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1 11255 MOV SECOND STAGE Fall AS IS g g ]B42 2Pis? SJAE SUCTION j
. i MOV SEPARATOR "B" Fall AS IS j g
l DRAIN l g
l l 1125-6 MOV INTERCONDENSER Fall AS IS l
! *B" DRAIN f l '
l MOV FIRST STAGE SJAE FAIL AS IS g g j
l "B"lNLET
- LOSS OF CONDENSER VACUUM AND TURBINE 1126 2 N64 GAS DRYER SKlD AND LOSS OF PANEL"A" NONE. PANE L "B"-
CONTROLPANEL AVAILABLE TRIP AFTER TWO MINUTES WORSE CASE I N64 OFF GAS HYDROGEN LOSS OF ANALYZER "A" NONE,"B" AVAILABLE l l* ANALYZ ER "A" h N64 OFF GAS VALVES VALVES Fall AS IS NONE I LOSS OF SYSTEM NONE [
1126 3 N64 OFF GAS POWER SUPPLY NONE .!
N64 HEATER AND CONTROL LOSS OF HEATER ClRCUIT "A" N64 HEATER ANDCONTROL LOSS OF HEATER NONE 'd
( CIRCUIT "B" i
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IEB 79-27 SYS. COMPON ENT PRIM AR Y SECONDARY C0tl8IhAT104AE I TABLENO. 40. DESCRIPTION EFFECT iFFECT EFFECTS
.,'4 12 HE AC BUS ( 1126 1 N64 GLYCOL REFRIG COM- LOSS OF COMP WORSE CASE-LOSS OF TURBINE TRIP AFTER TWO MINUTES -WORSE PRESSOR "A" CONDENSE R VACUUM CASE t GLYCOL REFRIG COM-- LOSS OF COMP AND TURBINE TRIP ,",
1[8E4 ' #
, 12B42 PRF9SOR "C" AFTER TWO MINUTES
=
l GAS DRYER BLOWER "A" LOSS OF BLOWER -
1 I GLYCOL COOLER TANK k LOSSOF AGITATOR
- l l AGITATOR ,
GAS DRYER HEATER LOSSOF HEATER I CONDENSER GLYCOL PUMP LOSS OF PUMP ,.
l !C "A" l CONDENSER GLYCOL PUMP LOSS CF PUMP "C-MOV WATER SEPARATOR FAIL AS IS OUTLET CATALYTIC RECOMBINER LOSS OF TRANSFORME R .
E
( HEATE R TR ANSFORMER 1202-3 B33 REACTOR RECIRC SYSTEM PUMP B INOPERATIVE PLANT POWER LEVEL PLANT POWER LEVEL LIMITED 3
c RECIRC PUMP B MOTOR AT FULL SPEED LIMITED POWER CIRCUlT (PUMP A ON BUS 11 HD)
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PAGE 13OF 17 I.ttachment 2 ,
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- n IFB 79-27 PRlWARY SECONDARY COM8ttATlot4L SVs E0rP0nENT EFFECTS ..
DESCRIPTION EfIECT EFFECT T ABLE hD. h 0. '4 TURB CONT SYS BCU/IPC LOSS OF AC POWER NONE-BATTERY BACK-UI' 13AD ^ 0 1131-6 N32 f
AUX CH B (SEE BATTERY BLS- J#
13BD1 13811
- t TURB CONT SYS BCU/IPC LOSS OF AC POWER IIDH AND 11DJ) j M y CHANNE L 1 CAB j TURB CONT SYS BCU/IPC LOSS OF AC POWER t g
CHANNEL 2 CAB ~j I TURB CONT SYS BCU/IPC LOSS OF AC POWER l l
' CHANNEL 3 CAB l 13Pi2 ( ' j LOSS OF AC POWER NONE BATTERY BACK-UI NONE l 13812 1132-10 N32 TURB CONT SYS ELECTRO-j HYDRAULIC CONTROLLER (SEE BATTERY BUS.
l j
! I 11DH AND 11DJ) '
l I r i L _
y, WORSE CASE- PARTIAL LOSSOF FEEDWATER j I -4 HEATING l l "
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1 l 1132-2 N21 FEEDWATER SYSTEM HIGH MOV F009A-N F AILS ASrtS F AILED CLOSED- LOSS O
' r l PRESS. F EEDWATER H.P. FN STRING. PLANT
, y HEATER OUTLET MOV
- POWER LIMITED TO 95%
g -
f 1 MOV F042A-N F AILS AS IS F AILED CLOSED-LOSS 01 I N19 CONDENSATE SYSTEM LOW l PRESS. FEEDWATER HTRS LP. F W STRING "A" l
l STRINGS"A" INLET MOV l MOV F040A-N FAILS AS-IS F AILED CLOSED-LOSS O l N19 CONDENSATE SYSTEM LOW l l PRESS FEEDWATER HTRS L.P' FW STRING "A" ,
I l i t STRINGS "A" OUTLET MOV l(
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Common flug Tree Table '
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- ;, 3 IEB 79-27 SYS. COMPOWE NT PRIMARY SECONDARY COWllhATIONAL [
TA8tf ho. N O. DESCRIPTION EFFECT EFFECT 4 E F F E CT5 ;3 IMD AC BUS f
~ ~~
'I gCont'd) 13P12 1132 3 N36 EXTRACTION STEAM SYS. MOV F010A-N FAILS ASIS FAILED CLOSED-LOSS PARTIAL LOSS OF FEEDWATER HEATING
< ,i l FEEDWATER HTR 5A lNLET OF FEEDWATER HTR I B005A ,,
l N36 EXTRACTION STEAM SYS. MOV F011 A-N FAILS ASIS F AILED LLOSED-LOSS )
1 FEEDWATER HTR 6A INLET OF FEEDWATER HTR B006A 1132-5 N36 EXTRACTION STEAM SYS, BTV F013 FAILL CLOSED LOSS OF B0058 FEED- i l F EEDWATER HEATER WATER HEATER N36 EXTRACTION STEAM SYS, BTV F012 FAILS CLOSED LOSS OF B0068 F EED-l FDW HTR & DRAIN VALVE F008A FAILS OPEN WATER HEATER
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- i Common Pua Tree Table i IEB 79-27 SYS Courchthi PRIV AR Y 5tC0h0ARY COVEth AfichAL s 13A D AC BUS T ABLE h0. h0. DESCRIPTich EffECT EfftCT EfftC15 138D2 (Conr0 + i 1134 2 N62 CONDENSER AIR REMOVAL LOSS OF PRESSURE LOSS OF CONDENSER - WORSE CASE MAIN TURBINE TRIP-AFTE R SOME ;
! 13p21 L i .
g SYSTE M CONTROLLERS VACUUM-TURBINE DELAY 5 l ,
TRIP r I i a
i 13P21 r 1134 1 N19 CONDENSATE BOCSTER F All AS IS F All OPE N - NONE NO IMMEDIATE EFFECT UNLESS FEEDWATER 1 l PUMP DISCH ARGE VALVE FAIL CLOSED -LOSS OF FLOW DEMAND INCREASES C0028 PUMP
N19 CONDENSATE BOOSTER Fall AS IS F All CLOSED - LOSS
! PUMP SUCTION MOV OF C002B PUMP I 1134-5 N19 CONDENSATE MOV SPACE F All AS IS WORSE CASE - LOSS OF I le ; HEATER C003A PUMP, C002A l N19 CONDENSATE MOV# UMP F AIL AS l$ PUMP, "B" DISCH.
N19 CONDENSATE MOVPUMP FAIL AS IS "A* SUCTION N19 CONDENSATE MOV- PUMP FAIL AS IS l "B" SUCTION ;
1134 6 N19 CONDENSATE MOV4 UMP FAIL ASIS "A" DISCHARGE 13802
] 1 822 11351 135 MOISTURE SEPARATOR FAIL AS IS WORSE CASE - LOSS PARTIAL LOSS OF FEEDWATER HEATING
] j l
! i l j j l 11353 123 FEEDWATER HEATER 4A & FAIL AS IS (CLOSED) DUMP VALVE WILL _
l 3A LEVEL CONTROL VALVES MAINTAIN LEVEL. HEAT. t I l
( ERS MAY LOSE EFFI- 1 5
I I l' A CIENCY. i J
t I r 1203 1 N19 CONDENSATE BOOSTER PUMPS INOPERATIVE NONE RFPT A & B WILL TRIP ON LOW SUCTION , i PUMPS C002 A & C0028 PRESSUR E l
12032 N19 CONDENSATE PUMP PUVP INOPE RATIVE NONE ;
l C003A 3 I i j N23 HEATER ORAIN PUMP A PUVP A INOPERATIVE NONE I
($ ACE UP PUMP B ON BUS h 4
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' . .4 IEB 79-27 SYS CourotENT PRIMARY SECOND ARY COMB 14AT10hAL ;
TABLE ND. 20. DESCRIPTION EFFECT EFFECT EFFECTS .
I 14 AE AC BUS f 1143-2 N36 EXTRACTION STEAM H.P. HEATER STRING PARTIAL LOSS OF FEEDWATER HEATING 4( ,
SYSTEM "B" OUT & FEEDWATER FLOW i 1,;.
14BE2 .i I 1143-3 N36 EXTRACTION STEAM Fall AS IS DROP IN WATER TEMP ' '3
' pB21 i 1 SYSTEM FW HEATER VALVE TO REACTOR s -I l l 1143 7 N21 HIGH PRESSURE FW HEATER FAIL ASIS FAIL OPEN-HEATE R
, START-UP MOV OU'PUT BYPASSED TO 1, g CRW,95% OF FEED-WATER FLOW TO ;
14822 i g REACTOR
, 11P22 ( #
l 1144- 5.6 N64 OFF GAS CONTROL SYS. LOSS OF POWER SUPPLY WORSE CASE IS WORSE CASE-TURBINE TRIP l l 1 ' OWE R SUPPLY , TURBINE TRIP
~
[ 1204 1 N32 CONTROL FLUID PUMP LOSS OF PUMP BACK.UP AVAILABLE. WORSE CASE-TURBINE TRIP e TURSINE TRIP IF NOT.
N23 HEATER DRAIN PUMP 8 PUMP B INOPERATIVE (BKU NO EFFECT RFPT A & B WILLTRIP PUMP A ON BUS 13AD )
N19 CONDENSATE BOOSTER PUMPS INOPE RATIVE RFPT A & B WILL TRIP PUMPS C002C, C0038,C003C ON LOW SUCTION PRESSURE
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Attachment 2 .
Common Bus Tree Table -
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PRIMARY SECCADARY COMBINAfl0NAL ,P IEB 79-27 SYS. COMPONENT TABLE No. N o. DESCRIPTION EFFECT EFFECT EFFECTS 15AA AC bus 15BA3 PS2 SERVICE AIR LOSS OF BACK-UP AIR MSIV CLOSURF, REACTOR SCRAM i
11512 gsgyeS CLOSE ,
' 15Bf1 15431 g PS3 DSTRIMENT AIRTO C(1.7AINl I ASS OF INSTRINENT AIR ..
J
,i FILT,DRYWELL. & AUX BLDG. )
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15BA 1157-5 B33 ATWS INSTRUMENTS TRIP RECIRC PUMPS REDUCED REACTOR ATWS TRIP *A" 5861 1961 .i
- POWER SUPPLY (ATWS TFilP "B" ON BUS POWER 3 l 16AB) j 16ABI l 1
's' 15831 j6P31 11612 P53 INSTRUMENT AIR BOOSTER LOSS OF BOOSTER NO EFFECT
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i p NONE ;j
[
l LOSS OF BOOSTER l P53 INSTRUMENT AIR BOOSTER NO EFFECT
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[ 12062 P53 INSTRUMENT AIR COMPRESSOR LOSS OF INSTRLMENT AIR NONE ONE
( (SERVICE AIR IS BACK-UP) {
1167-3 B33 ATWS INSTRUMENTS TRIP RECIRC PUMPS REDUCED REACTOR ATWS TRIP "B" I 1
H POWER SUPPLY (ATWS TRIP "A" ON BUS POWER l [ 15AA) i I I L i 16P61 I 16B61 j 16886 j .
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.P;g2 1.cf 4 Attachment 3 Combinational Effects of Common Bus Loss DC BUS 11DA - The effect of loss of this bushis the loss of the normal recirculation pump.A & B trips. Since the'1E trips powered by safety busses are still available, there are no ef fects on reactor parameters and hence no effect on the Chapter-15 analysis.
DC Bus 11DB - TFe effect of loss of this hus is the loss of ability to-transfer recirculation pumps A & B from the LFMG power _to the normal power source and hence limits the pumps to 25% of normal flow. Limitation of power falls within normal operational limits and does not affect the Chapter 15 analysis.
The Loss of this bus at full power has no effect since the recirculation pumps will be on the normal power source.
DC BUS 11DH - These two busses provide back-up power to the main turbine DC BUS 11DJ controls. Normal power is supplied by AC bus 13AD. Loss of either of these busses will cause no transient and hence l no effect on the Chapter.15 analysis.
DC BUS 11DD -
The busses supplied by 11DD are analyzed separately as follows:
AC BUS 1Y74 - Loss of this bus will cause a loss of control of recirculation loop 'A'. The control valve fails as is and there will be no effects on reactor parameters of water level, pressure, or power, since the
'B' loop will adjust to compensate for any demand changes. Loss of this bus will also cause a total loss of feedwater. This event is analyzed in Chapter 15.2.7. There is no additional consequence of loss of recirculation control since reactor parameters are not affected.
AC BUS 1Y71 - Loss of this bus will cause a loss of icedwater control and l
other elements of the feedwater system. There is also the possibility as a worst case effect of a coincident partial loss of feedwater heating. Normal
! operator action in this event would be to manually control the feedwater pumps and shutdown the plant.
As a result of the total loss of feedwater control the reactor water level may increase significantly, decrease significantly, or remain relativc1y unchanged.
If the water level increases significantly and reaches the high water level trip point, a reactor scrcm and a feedwater turbine trip will result. This event is bounded by the feedwater controller failure event analyzed in Chapter 15.1.2.
B1211g1
Paga 2 of'4 Attachment 3
- Combinational Effects of Common Bus Loss (Continued)
If the water level decreases significantly and reaches the low water level trip point, a reactor scram will result. This event is bounded by the loss of feedwater event analyzed in Chapter 15.2.7.
In either one of these two events the effect of the loss of feedwater heating vill not reach the vessel quickly enough to change the event -before a reactor scram.
If the water level remains relatively unchanged, this event is bounded by the loss of feedwater heating event analyzed in Chapter 15.1.1.
DC BUS IDD1 -
Loss of this bus will cause a loss of the' feedwater speedchanger A and a~possible trip of the main turbine. If the feedwater 'A' control is being operated in the full automatic mode, loss of this remote manual capability has no effect on the automatic control. If operated in the tr.nual mode, the speed changer fails as is and the RFPT speed will remain at the last setting. In either case the reactor water level is not affected.
Main turbine trip is analyzed in Chapter 15.2.3.
DC BUS IDD2 - Loss of this bus will cause the loss of the ability to trip
! feedwater turbine A remotely. There would also be a partial loss of feedwater heating and loss of the remote manual control of feedwater turbine A. The loss of the feedwater turbine trip would not affect the feedwater heating loss event which is bounded by Chapter 15.1.1. The loss of remote manual feedwater
' A' control is discussed under bus 1DDI except for a possible reactor water level decrease due to the increased power from colder feedwater. Loss of the feedwater turbine trip would not affect this event either since the water level is decreasing.
i The only other combination of failures possible on Bus 11DD, since two of the
[ sub-busses are inverter fed with e.utom tic transfer to the AC beck-up, is the coincident loss of 1DDI and IDD2. This event would be identical to the Bus IDD2 event except for the immediate initiation of safety systems in the
- event of a main turbine trip. Main turbine trip is analyzed in l Chapter 15.2.3.
DC BUS 11DE - The busses supplied by llDE are analyzed separately as follows:
AC BUS 1Y76 - Loss of this bus will cause a loss of control of recirculation loop 'B'. The control valve fails as is and there will be no ef fects on reactor parameters of water level, pressure or power, since the
'A' loop will adjust to compensate for any demand changes.
Loss of this bus also causes a loss of automatic control of RFPT B. If RFPT A is in the full automatic node at the time of this event, normal reactor water level will be maintained by RFPT A. If RFPT A is in the manual mode, the water level may increase, decrease, or remain the same as discussed under bus lY71. This event is bounded by Chapter 15.1.2 and 15.2.7 for increase or decrease in water level. There is no additional consequence of loss of recirculatien control since reactor parameters are not affected.
Paga 3 ef 4 Attachment 3 Combinational Effects of Common Bus Loss (Continued)
DC BUS 1DE1 - Loss of this bus will cause a loss of the feedwater speedchanger. If the feedwater 'B' control is being operated in the full automatic mode, loss of this remote manual capability has no effect on the automatic control. If operated in the manual mode, the speed changer fails as is and the RFPT speed will remain at the last setting. In either case the reactor water level is not affected and causes no transient.
DC BUS 1DE2 - Loss of this buss will cause the loss of the ability to trip feedwater turbine B from the control room and a loss of control of feedwater turbine B. The loss of feedwater turbine B control is discussed under bus IDEl. Loss of the feedwater turbine trip does not complicate this event.
The only combination of failures possible on Bus 11DE, since 1Y76 is inverter fed with automatic transfer to the AC back-up, is the coincident loss of IDE1 and IDE2. This event would be bounded by the loss of IDE2 alone and cause no transient.
AC BUS 11HD - The effect of this bus is the crip of recirculation pump A to the LFMG set power. This limits plant power but does not affect the Chapter 15 analysis.
AC BUS 12HE - The worst consequence of the loss of individual busses fed from 12HE, or loss of 12HE itself, is possible loss of condenser vacuum and turbine trip in conjunction with loss of some feedwater heating. The most severe event has been identified to be the loss of condenser vacuum in conjunction with the loss of feedwater heater. Timing would be an important factor to determine the severity of the consequence. The worst combination of these two events would be that the low vacuum induced turbine trip occurs prior to the thermal power monitor (TPM) scram or at the maximum power level if the TPM scram setpoint has not ever been reached.
An ODYN run was performed to simulate this event for Grand Gulf initial core. The maximum temperature reduction resulting from the single power source failure was identified to be 68* F, which was used in the analysis. The result showed that the thermal power leveled of f at 110% NBR power prior to the turbine trip. The peak heat flux at the turbine trip was approximately 110% NBR. The change in CPR is estimated to be only 0.06 compared to 0.12 for the loss of feedwater heater event evaluated in FSAR Chapter 15. The maximum dome pressure was 1212 psia which was bounded by the Chapter 15 turbine trip with bypass failure case (1217 psia). Thus, the loss of bus 12HE event is bounded by the FSAR Chapter 15 analysis.
Pcg2 4 cf 4:
Attachment 3 Combined Effects of Common Bus Loss - (Continued)
AC BUS 13AD - The worst case combination of failures associated with this bus would be a main turbine trip and a partial loss of~
feedwater heating. This. event is bounded by the FSAR.
Chapter 15 analysis as described under Eus'12HE.
AC BUS 14AE - The worst. case combination of failures associated with this-bus is partial loss of feedwater heating and a main turbine trip. This event is identical to the bus 12HE failure and is bounded as described above under bus 12HE.
AC BUS 15AA - The effect of loss of the busses fed from 15AA is either a loss of instrument air which is analyzed in Chapter 15.2.10 or a trip of both recirculation pumps which is analyzed in Chapter 15.3.1. Loss of bus 15AA itself will initiate both events. Recirculation pump trip would also occur as a result of the loss of instrument air scenario and there is no reliance on recirculation pump operation in the loss of instrument air analysis.
AC BUS 16AB - The ef fect of the loss of this bus is identical to 15AA and therefora bounded by Chapter 15 analysis.
AC BUS 12R - This bus feeds 11HD, 12HE, 13AD, 14AE. Loss of bus will cause a plant scram and MSIV closure since it supplies the RPS MG sets. The analysis lin Chapter 15.2.6 would bound this event.
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Attachment 4 Common Instrument Table 1:
n COMMON LINES INSTRUMENT INST FUNCTION SYSTEM AFFECTED EFFECT OF BR0litle LINE PLUGGEO LINE C0ameENT h NO.1 LOWER 821-LT-N0998 ATWS RX VESSEL LEVEL AFFECTS REACTOR INSTRUMENTS INDICATE LOSS OF TRIP FUNCTION. NO RECIRC PUMP
- j TAP B21-LT-N099F ATWS Rx VESSEL LEVEL RECIRC SYSTEM ONLY LOW WATER. TRIPS TO EFFECT WITHOUT ADDITIONAL TRIPS ANALYZED
,., BOTH RECIRC PUMPS FAILURES
- .,: IN CH.13.3.1
'-[ $ [ , +f NO. 2 UPPER 821 LT-N0998 ATWS RX VESSEL LEVEL WATER LEVEL INSTRU. LOSSOF LEVELTRIP FUNC-V k'fd * '
- TAP B21.LT-N099F ATWS RX VESSEL LEVEL MENTS INDICATE HIGH TION, NO EFFECT WITHOUT SAME
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. , , C34 LT.N0048 FW LEVEL B AFFECTS REACTOR WATER, NO TRIP TO RECIRC ADDITIONAL FAILURES AS.
Cd Nh;gQ ONLY B33-PT-N040 VESSEL DOME PRESSURE RECIRC SYSTEM &
FEEDWATER CONTROL PUMPS NO TRIP TO FEED-WATE R (Requwes 2 out of 3)
ABOVE TAP SYSTEM
. -lf, ?*ep@g' g B21-PT N058B ATWS VESSE L PRESSURE PRESSURE INSTRUMENTS - WORSE CASE IS ATWS TRIP a ' 'd[%
INDICATE LOW PRESSURE OF BOTH RECIRC PUMPS,
, YE '# 5 . B21-PT-N058F ATWS VESSEL PRESSURE NO TRIPS OCCUR DOMINANT EFFECT IS A i
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TRIP EVEN WITH LOSS OF '
LEVEL TRIP.
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B21-LT-N099A ATWS RX VESSEL LEVEL AFFECTS REACTOR y m;@fe'ddgg g r -~
TAP B21 LT-N099E ATWS RX VESSEL LEVEL RECIRC SYSTEM ONLY SAME AS NO.1 SAME AS NO,1 SAME AS ABOVE gY 4y-1"d*) NO. 4 UPPER 821-LT.N099A ATWS RX VESSEL LEVEL 4 -
TAP B21 LT099E ATWS RX VESSEL LEVEL AFFECTS REACTOR
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'./ i ~ ? , , C34 LT-N004A FW LEVEL A RECIRC SYSTEM &
, ".. ] F EEDWATER CONTROL
. ,i" ';g ONLY C34-PT-N005 WIDE RANGE PRESSURE SYSTEM SAME AS NO.2 SAME AS NO.2 SAME AS ABOVE
,. -3 TAP
, ;. 821-PT-N058A ATWS VESSEL PRESSUR E
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B21-PT-N058E ATWS VESSEL PRESSURE '
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,, 6 THESE INSTRUME5fTS
~ - ARE LOCATED WITH BOTH ELECTRICAL AND MECHANICAL DIVISION TAKEN INTO CONSIDERATION
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