ML20140G813

From kanterella
Jump to navigation Jump to search
Forwards Morning Rept Discussing 850912 Planned Load Rejection Test W/Reactor Power Level at 55%.Test Resulted in Unanticipated Sequence of Turbine Trip,Bus Failure,Reactor Trip & Safety Injection.Event Being Reviewed
ML20140G813
Person / Time
Site: Palo Verde, 05000000
Issue date: 09/23/1985
From: Houston D
Advisory Committee on Reactor Safeguards
To: Ebersole J
Advisory Committee on Reactor Safeguards
Shared Package
ML20140B723 List:
References
FOIA-86-45 NUDOCS 8604030596
Download: ML20140G813 (29)
v • d • e


Text

_ _ . _ _ . _ _ . . . -

/ ~% ~

UNITED STATES

,8 , j NUCLEAR REGULATORY COMMISSION e r ADVISORY COMMITTEE ON REACTOR SAFEGUARDS

'oh [ WASHINGTON D. C. 20555 September 23, 1985 MEMORANDUM FOR: J. Ebersole, Chairman Palo Verde Nuclear Station Subcommittee FROM: D. Houston, Staff Engineer

SUBJECT:

PALO VERDE UNIT 1 LOSS OF LOAD EVENT On September 12, 1985, a planned load rejection test was performed at Palo Verde, Unit 1, with the reactor power level at 55%. This test led to the unanticipated sequence of turbine trip, bus failure, reactor trip, safety injection, containment isolation and loss of pressurizer auxiliary spray system. Attached are copies of the morning reports and OR Briefing slides that describe the sequence of events and the NRC concerns about it. The pressurizer did not require the spray system to function for pressure reduction. However, the spray would have been unavailable during the event. The primary spray is fed off the reactor coolant pump discharge and these pumps had tripped on undervoltage. The auxiliary spray is fed from charging pumps and these were unavailable due to the bus failure (autotransfer malfunction).

The Staff is still reviewing many aspects of this event. I am told that Region V has issued a Conformation of Action letter to the Utility which prohibits start-up of Unit I until these concerns are satisfactorily resolved. When available, I will provide the Staff's SER on this matter.

Attachments: As Stated cc: ACRS Members ACRS Technical Staff ACRS Fellows 8604030596 860311 PDR FOIA SC3TT86-45 PDR '1

n

4 2 * '

l

. ( l

~

MORNING REPORT - REGION V DATE: SEPTEMBER 13, 1985 .

i ITEM OR EVENT REGIONAL ACTION AN UNUSUAL EVENT HAS DECLARED AT 10:23 PM THURSDAY, l

SEPTEMBER 1Z, 1985, FOLLONING AN UNPLANNED REACTOR TRIP. FOLLOWUP PER MC 2515 AT 10:10 PM AN UNPLANNED MAIN TURBINE TRIP GCCURRED HHEN A PLANNED LOAD REJECTION WAS INITIATED DURING THE CONDUCT OF POWER ASCENSION TESTING AT UNIT t. WITH THE REACTOR AT 55% FULL POWER, A CONDITION UF THE PL ANNED TEST, THE MAIN GENERATOR WAS SUPPLYING APPROXIMATELY 70 MH OF HOUSE LOADS TO THE REACTOR COOLANT PUMPS (RCPS) AND NON VITAL LOADS ON THE 13.8 KV ELECTRICAL BUSSES. AFTER THE TURBINE TRIPPED THE LOADS ON THE MAIN GENERATOR DID NOT AUTOMATICALLY TRANSFER TO THE STARTUP TRANSFORMER AND SEQUENTIALLY DEENERGIZED UNTIL THE RCPS TRIPPED ON LOW VOLTAGE.

THE REACTOR TRIPPED WHEN THE CORE PROTECTION CALCULATOR SENSED THAT THE RCPS HAD TRIPPED. FOLLOWING THE REACTOR TRIP. THE PLANT OPERATORS MANUALLY REENERGIZED THE 13.8 KV NONESSENTIAL SUSSES. WHEN THE BUSSES REENERGIZED, DRAIN VALVES ON THE MAIN STEAM HEADER AND ON THE MAIN TURBINE STOP VALVES, HAD AUTOMATICALLY STARTED TO OPEN WHEN THE MAIN TURBINE TRIPPED AND THEN STOPPED NMEN POWER WAS LOST, AND CONTINUED TO COMPLETE THE OPENING. THE INCREASED COOL DOWN OF THE REACTOR COOLANT SYSTEM (RCS) CAUSED THE PRESSURIZER PRES $URE AND LEVEL TO DECREASE TO THE SAFETY INJECTION SETPOINT. THE SAFETY INJECTION ALSO INITIATED A CONTAINMENT SUILDING ISOLATION. THE STATION EMERGENCY PLAN REQUIRES THAT WITH A REACTOR TRIP, SAFETY INJECTION

' AND CONTAINMENT ISOLATION, AN UNUSUAL EVENT BE DECLAREC.

OPERATORS SHUT DOWN THE DRAIN VfLVES AT 11:24 PM AND COMMENCED RESTORING THE PLANT TO NORMAL STATUS. AFTER PRESSURIZER PRES $URE AND LEVEL NERE RESTORED AND THE RCPS STARTED, THE UNUSUAL EVENT WAS TERMINATED AT 1:03 AM SEPTEM8ER 13, 1985. THE LICENSEE IS MAINTAINING THE PLANT IN MODE 3 NHILE DETERMINING THE CAUSE OF THE TURBINE TRIP, AND MAKING MODIFICATIONS TO THE MAIN STEAM HEADER AND MAIN TURBINE STOP VALVE CONTROL CIRCUITRY TO PREVENT THE VALVES FROM OPENING AUTOMATICALLY AFTER A TURBINE TRIP.

ALL ENGINEERED SAFETY FEATURES PERFORMED AS REQUIRED.

THE RESIDENT INSPECTOR HAS ON $1TE DURING THE RECOVERY FROM THE EVENT. THE NEWS MEDIA NAS NOTIFIED OF THIS EVENT.

Raportable Event number 00066 .

Fccility : ,fALO VERDE Date Notified : 09/13/85 Unit : 1 Time Notified : 01:56 Rsgion : 5 Date of Event : 09/1~/85 Vandor : C-E,C-E,C-E Time of Event : 00:10 OpGrations Officer : Chouncey Gould Classification : Unusua! Event

  • NRC Notified By : TAYLOR Categcry 1 : SCRAM Red Release : No Category 2 : ESF Actuation Ccune : ELECTRICAL Category 3 :

Corr.p enen t : BUS NANSO1 & SO2 Category 4 :

EVENT DESCRIPTICN :

t PLANT HAD RTR TRIP FROM 54% ON LOW RCS FLOW SIGNAL DUE TO LOSS OF RC PUMPS

" CECAUSE OF LOSS OF POWER TO NANSO1 & S02 BUS WHICH OCCURRED DURING A LARGE t

LOAD REJECTION TEST WHEN THE BUS FAILED TO AUTO TRANSFER FROM THE GENERATOR BACK TO THE STARTUP TRANSFORMER. THEY ALSO LOST THE CIRC WATER FMPS WHICH ARE POWERED BY THE SAME BUS. THE CAUSE OF THE TRANSFER FAILURE IS BEING INVESTIGATED. SI OCCURRED ON LOW PRESSURE IN THE FRIMARY AND THEY ALSO GOT CONTAINMENT, ISOLATION. AT THIS TIME THE AMOUNT OF WATER INJECTED HAD NOT BEEN CALCULATED. THE PLANT IS IN HOT S/B AND NATURAL CIRCULATION WITH THE SI PMPS STILL ON. PLANT ALSO HAS THEIR AUX FEED PMPS OPERATING. *** UPDATE ***

l NOUE TERMINATED AT 010CMT. PLANT HAS 2 RC PMPS RUNNING. SI WAS ALSO SECURED. NOTIFIED RDO CREWS,ED PARTLOW, FEMA GREINER I

. . . = . _  :-a . . . . i

. t o

PALO VERDE UNIT 1 - REACTOR TRIP, SAFETY INJECTION, LOSS OF PRESSURIZER AUXILIARY SPRAY SYSTEM SEPTEMBER 12, 1985 (E. A, LICITRA, NRR)

_ PROBLEM - DURING LOSS OF LOAD TEST PL TRIP, REACTOR TRIP, SAFETY INJECTION, CONTAINMENT ISOLA AND LOSS OF PRESSURIZER AUXILIARY SPRAY SYSTEM SAFETY SIGNIFICANCE - THE PRESSURIZER AU WAS NOT AVAILABLE, IF REQUIRED, FOR RAPID COOLDOWN AND DEPRESSURIZATION OF REACTOR COOLANT SYSTEM (P NOT HAVE PORVS)

DISCUSSION PLANT AT 557. POWER FOR LOSS OF LOAD TEST 'rf!T GENERATOR SUPPLYING ONSITE LOADS, INCLUDING RCP'S ON LOSS OF LOAD, GENERATOR FAILED TO PROVIDE POWER TO ONSITE LOADS; RCP TRIPPED ON UNDERVOLTAGE REACTOR TRIPPED ON PROJECTED LOW DNBR AUTOMATIC TRANSFER TO OFFSITE POWER FOR N LOADS DID NOT OCCbR i

AUXILIARY FEEDWATER SYSTEM WAS MANUALLY ACTUA LOW RCS PRESSURE CAUSED SI INITIATION PLANT STABILIZED IN HOT STANDBY; RCPS RESTORED IN ABOUT ONE HOUP TEST WAS PE-RUN WITHOUT INCIDENT ON SEPTEMBER 16, 1985, WITH A MODIFIED TEST PROCEDUPE

m.u_. . m .a . - _ _ _

. t NRC FOLLOWUP ACTION (1) CONFERENCE CALL WITH LICENSEE ON SEPTEMBER 16, 1985 (2) EVALUATING SINGLE FAILURE VULNERABILITY OF AUXILIARY SPRAY SYSTEM FOR PRESSURIZER PROBLEMS BEING EVALUATED F

A. DOES PRESSURIZER AUXILIAP.Y SPRAY SYSTEM MEET SINGLE FAILURE CRITERION?

B. IN RESTARTING THE PLANT, DID THEY VIOLATE TECHNICAL SPECIFICATIONS?.

C. WHY DID TURBINE TRIP ON LOSS OF LOAD AT 55% POWEP?

(SUPPOSEDTOSTAYOh4TOHANDLEHOUSELOADS)

D. WHY WAS TEST INITIALLY RUN BEFORE CHECKING WHETHER AUTOMATIC TRANSFER TO OFFSITE POWER FOR THE NONESSENTIAL LOADS COULD TAKE PLACE? (AUTO TRANSFER DID NOT OCCUR)

, E. REPORTING OF INCIDENT WAS INCOMPLETE AND INACCUPATE

+

.s. . .r, u .- . . . ...A

~~ _ ,

uj

, 4 AGENDA PRESSURIZER AUXILIARY SPRAY DESIGN REVIEW OCTOBER 8, 1985 INTRODUCTION R.M. BUTLER DIRECTOR OF TECHNICAL SERVICES, ANPP DESIGN HISTORY G.A. DAVIS MANAGER, STANDARD PLANT LICENSING, CE SGTR USE OF AUX SPRAY G.W. S0WERS SUPERVISOR OF SAFETY ANALYSIS, ANPP EXISTING DESIGN B.K. MCOUDID SYSTEM ENGINEER, CE DESIGN MODIFICATIONS M.A. RADSPINNER MECHANICAL ENGINEER, ANPP

SUMMARY

T.F. QUAN LICENSING SUPERVISOR, ANPP

. ,. . Ii

. . __ . . . _.__ m_. . . _ _ _ _. _ -

i i DEFINITION OF SYSTEMS THAT ARE SAFETY RELATED l ,

l FROM 10CFR100, APPENDIX A:

i "CERTAIN STRUCTURES, SYSTEMS, AND COMP 0NENTS ARE DESIGNED TO REMAIN FUNCTIONAL [AFTER A SAFE SHUTDOWN EARTH 00AKEl. THESE

STRUCTURES, SYSTEMS, AND COMPONENTS ARE THOSE NECESSARY TO l ASSURE

(1) THE INTEGRITY OF THE REACTOR COOLANT PRESSURE B0UNDARY, (2) THE CAPABILITY TO SHUT D0WN THE REACTOR AND MAINTAIN IT IN A SAFE SHUTDOWN CONDITION, OR (3) THE CAPABILITY TO PREVENT OR MITIGATE THE CONSEQUENCES OF j ACCIDENTS WHICH COULD RESULT IN POTENTIAL OFFSITE EXPOSURES COMPARABLE TO THE GUIDELINE EXPOSURES OF THIS PART."

l I

c. .

-_.u..-... -

. -s REQUIREMENTS FOR SAFETY RELATED SYSTEMS o MINIMUM REQUIREMENTS ARE SPECIFIED IN 10CFR50, APPENDIX A - GENERAL DESIGN CRITERIA FOR NUCLEAR POWER PLANTS o GDC'S RECOGNIZE THAT SPECIFIC REQUIREMENTS FOR EACH SYSTEM DEPEND ON FUNCTION PERFORMED o ACCEPTABLE METHODS FOR MEETING GDC'S PROVIDED IN:

REGULATORY GUIDES STANDARD REVIEW PLANS BRANCH TECHNICAL POSITIONS r-

^ ~ ^

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

o i

} .

COLD VS. HOT SHUTDOWN o PRIOR TO 1978, SAFE SHUTDOWN WAS TAKEN TO MEAN l H0T SHUTDOWN o IN 1978, NRC ISSUED NEW GUIDANCE ON GDC'S WHICH EFFECTIVELY DEFINED SAFE SHUTDOWN AS COLD SHUTDOWN (BRANCH TECHNICAL POSITION RSB 5-1)

[

o RSB 5-1 SPECIFIES THAT:

I

~

"THE DESIGN SHALL BE SUCH THAT THE REACTOR CAN BE TAKEN FROM NORMAL OPERATING CONDITIONS TO COLD SHulDOWN USING ONLY SAFETY-GRADE j SYSTEMS."

s l'

o RSB 5-1 IDENTIFIES THREE CLASSES OF PLANTS FOR IMPLEMENTATION:

i CLASS 1, (NEW PLANTS) FULL COMPLIANCE CLASS 2, (PLANTS UNDER CONSTRUCTION) PARTIAL

IMPLEMENTATION CLASS 3, (OPERATING PLAPTS) BACKFIT o CESSAR AND PALO VERDE ARE IN CLASS 2

'f

,4 ry Am- e. enn e.dme e t

RECOMMENDED IMPLEMENTATION FOR CLASS 2 PLANTS

o CONCERNING AUXILIARY PRESSURIZER SPRAY, TABLE 1 0F BTP RSB 5-1 STATES

POSSIBLE SOLUTION FOR RECOMMENDED IMPLEMENTATION FOR i FULL COMPLIANCE CLASS 2 PLANTS PROVIDE UPGRADING AND ADDIT 0NAL COMPLIANCE WILL NOT BE REQUIRED IF VALVES TO ENSURE OPERATION OF A) DEPENDENCE ON MANUAL ACTIONS AUXILIARY PRESSURIZER SPRAY INSIDE CONTAINMENT AFTER SSE OR USING ONLY SAFETY-GRADE SUB- SINGLE FAILURE OR B) REMAINING AT SYSTEM MEETING SINGLE FAILURE. HOT STANDBY UNTil MANUAL ACTIONS OR POSSIBLE ALTERNATIVE MAY INVOLVE REPAIRS ARE COMPLETE ARE FOUND TO 4

USING PRESSURIZER POWER-0PERATED BE ACCEPTABLE FOR THE INDIVIDUAL i RELIEF VALVES WHICH HAVE BEEN PLANT.

UPGRADED. MEET SSE AND SINGLE FALURE WITHOUT MANUAL OPERATION INSIDE CONTAINMENT.

C _ .. _ _ _. . .;.

. z. . . _ . . m- . , . .

. s I

SCOPE OF AUXILIARY PRESSURIZER SPRAY SYSTEM o AUXILIARY PRESSURIZER SPRAY SYSTEM BEGINS AT BRANCH FROM CHARGING SYSTEM AND ENDS AT PRESSURIZER SPRAY N0ZZLES l' o MECHANICAL COMPONENTS CONSIST OF:

I --

PIPING TWO S0LEN0ID OPERATED VALVES (CH-203 & CH-205)

CHECK VALVE o SCHEMATIC 0F AUXILIARY PRESSURIZER SPRAY SYSTEM AND SOURCES OF B0 RATED WATER (VIA CHARGING SYSTEM)

SHOWN IN:

FIGURE 21-4 0F CEN-239, AND FIGURES 5 & 6 0F APPENDIX B IN NUREG-1044 See ge

. . - . a. . .-

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

t

't l

2' FIGURE 2.1-4

{

SIMPLIFIED SCHEMATIC 0F PALO VERDE CVCS SHOWING AUXILIARY I-SPRAY PORTION AND SOURCES OF BORATED WATER i' t

istLasIsNIC AC40 i 94 f0f M (. l A,a 4

5 CDP d i v Ist i>

tLasC AID ya yg,gggy~

A TA'O = ~~4a5 w _25_ -

=aa ~ >

a OP7th OPLl2 mtit r- .i camerant 7 * ~6 **

tm ELP M4f 4 e + i RtP 3 gf y i C8'"SM S- M

, cm.uF orses ower.us me OI-il(Pr d

- lLSIC ACID restic RPT' I Cle Il X .N l FSS , P*Ill llE

&1T,6 I

,,c,,,,, g o esi. M- m, e 8'e

..mc I T 5t* a

IWW

% 6 lT -

P AP.E 1P C es-oMein MSP 3 dL If 7 80 a(P M h Is&((fifts et Al txeres t e .

l

  • l' t

1 h

FIGURE 2,1-4 (cont.)

SIMPLIFIED SCHEMATIC 0F PALO VERDE CVCS SHOWING AUXILIARY [:

PORTION AND SOURCES OF B0 RATED WATER j; 6

matteamy 5,stav

,f__"'_'*"._55 ,

.!_k_  ! r

~~ -~-e.

4% Os I i f@_5___s !

t. .e _ _J ceu. " ,.n, "f,'gj'II . :n a

._, i ,,

e Ow IAl I ",= ,

,am acs

La. . _ -

. i HISTORY OF AUXILIARY PRESSURIZER SPRAY SYSTEM o PRIOR TO BTP RSB S-1 (1978), NO SAFETY RELATED FUNCTION o QUESTION 440 6 (ISSUED AND ANSWERED IN 1981), ADDRESSED SYSTEM 80 CONFORMANCE WITH BTP RSB 5-1

. o COMBUSTION ENGINEERING'S RESPONSE TO QUESTION 440 6

DESCRIBES OPERATION OF SPRAY SYSTEM AND THE PORTION OF j CHARGING SYSTEM WHICH PROVIDES WATER TO SPRAY SYSTEM o REQUIREMENT TO CONFORM TO BTP RSB 5-1 MADE THE AUXILIARY PRESURIZER SPRAY SYSTEM (AND A PORTION OF THE CHARGING SYSTEM) SAFETY RELATED o AFTER REVIEWING C-E'S RESPONSE TO QUESTION 440 6, RSB 4 TOOK POSITION THAT OPERATOR ACTIONS OUTSIDE OF CONTROL

, ROOM COULD ONLY BE USED TO MITIGATE SINGLE FAILURES l

t o FOLLOWING APPEAL MEETING WITH DIRECTOR OF SYSTEMS INTEGRATION ON SEPTEMBER 17, 1981, 3YSTEM 80 DESIGN WAS MODIFIED TO PROVIDE A MOTOR OPERATOR ON VALVE CH-141

, (LATER RENUMBERED TO CH-536) AND TO PROVIDE EMERGENCY l POWER TO CH-556 AND CH-501 FOLLOWING A LOP EVENT l

' se e .*

a. _ w . .. , . . . - .,-

l '. i l

HISTORY (CONT.)

i l o SUPPLEMENT NO 1 0F THE CESSAR SAFETY EVALUATION REPORT (ISSUED MARCH 1983) CONCLUDED THAT "THE GUIDELINES OF

BTP RSB 5-1 HAVE, THEREFORE, BEEN SATISFIED AND THIS ISSUE IS RESOLVED."

t i o IN CEN-239, COMBUSTION ENGINEERING AND ARIZONA PUBLIC l SERVICE RESPONDED TO NRC REQUEST FOR ADDITIONAL l INFORMATION ON THE DESIGN AND OPERATION OF THE AUXILIARY PRESSURIZER SPRAY SYSTEM I

o CEN-239 STATED THAT " AUXILIARY SPRAY PROVIDES THE l SAFETY-RELATED METHOD FOR RELATIVELY RAPID AND '

CONTROLLED DEPRESSURIZATION OF THE RCS TO COLD SHUTDOWN l CONDITIONS. AS SUCH THE SYSTEM HAS A DEGREE OF l PERFORMANCE CONSISTENT WITH THE NRC BRANCH TECHNICAL l POSITION RSB 5-1."

i o IN NUREG-1044, NRC STAFF EXPRESSED CONCERN ABOUT SINGLE FAILURE VULNERABILITY OF VALVE CH-240 CONCERN WAS RESOLVED BY ADDING VALVE CH-239, IN SERIES WITH CH-240 l

l l

l

J. .L.a . : . . t . ... - , , .

i STEAM GENERATUR TUBE RUPTURE _(SGTR) ANALYSES ,

I o ORIGINAL ANALYSIS INCLUDED IN CESSAR-F (TENDERED IN

1978):

BASED ON CATEGORIZATION MATRIX OF CHAPTER 15 (IN ACCORDANCE WITH REG. GUIDE 1 70, REV.2)

I -

TUBE RUPTURE ONLY l AUXILIARY PRESSURIZER SPRAY WAS NOT CREDITED FOR I ANALYSIS TO CALCULATE OFFSITE DOSES o ANALYSIS REVISED TO BE CONSISTENT WITH STANDARD REVIEW PLANS (1981/1982):

SGTR WITH AND..WITHOUT LOSS OF 0FFSITE POWER AUXILIARY PRESSURIZER SPRAY WAS NOT CREDITED FOR ANALYSIS TO CALCULATE OFFSITE DOSES CREDIT WAS TAKEN FOR THREE SECOND TIME DELAY BETWEEN REACTOR TRIP AND LOSS OF 0FFSITE POWER o NRC STAFF REQUIRED RE- ANALYSIS WITH ADDED SINGLE FAILURE AND RECOGNITION OF EMERGENCY OPERATING PROCEDURES PER CEN-152 (APRIL 1983) o SEPARATE ANALYSES WERE PERFORMED FOR CESSAR AND PALO VERDE (1984). BOTH ANALYSES RECOGNIZED USE OF AUXILIARY PRESSURIZER SPRAY (AS AN OPERATOR ACTION) o o NEW PALO VERDE ANALYSIS IS BEING PERFORMED, WHICH DOES NOT USE AUXILIARY PRESSURIZER SPRAY IN THE FIRST TWO HOURS

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

1. .

3 . .--

i

]

  • k t .

1

[

t h

SUMMARY

i) -

H 1

o AUXILIARY PRESSURIZER SPRAY SYSTEM AND PORTION OF' 3 CHARGING SYSTEM ARE SAFETY GRADE, AS REQUIRED BY NRC T0 l ' MEET BTP RSB 5-1 Li 1

i

].

a f

-1

.t 4

)

'l.

1 i

i 2:

q e .

l i;

t i!

4 ii j'

i'

._ m -

l I

PVNGS-FSAR (APPENDIX 15A)

. SGTR ANALYS!S QESilLTS t

FSAR

  • REVISED ANALYSIS
  • EVENT IIME. THYD010 DOSE TilYROID DOSE (SECONDS) (REM) (REM)

SGTR &

STUCK OPEN ADV 0 0 0 LOP 51 0 0 AFAS 132 0 0 ADV OPENS 460 0 0 MSIS 513 SIAS 581 AFH OVERPIDE 655 AllX SPRAY 1015/7200 115 115 ,

TUBES REC 0VEPED 1385/1347 182 186 2 HP DOSE a EAB 7200 200 208

  • REGULATORY DOSE LIMIT is 300 REM

~; . . . .

i  %

j 2500. i i i i i OPERATOR TAKES CONTRCL OF PLANT-0 PENS ONE ADV IN EACH SG d .

2000 l /

j h OPERATOR INITIATES AUXILIARY SPRAY

< < ~~

) E 1500 -[ \

OPERATOR CONTROLS AUXILIARY SPRAYFLOW, l Q g' BACKUP PPESSURIZER HEATER OUTPUT, AND y I HPSI FLOW IN ORDER TO KEEP THE RCS 20cp W

c. 1000

- l SUSC00 LED -

, g l 0 c: \

.J

' \

i RCS REACHES SHUTDOWN 500

\ COOLING ENTRY CONDITIONS

~

__ \_

I ' l I I '

0 0 5.000 10000 15000 2000 25000 30:::

TIME, SECONDS i

i r

I r

h Palo Ynde Nuclear Gmerating Station FSAR STEAM GCEPATCR WBE RUPWRE WITH 1455 OF OFFSITE PCWER A!C A 1111,I.Y SWCK OPDi ATHOSP}ERIC DUMP VALVE RCS PRESSURE VS TIME rigure 15A-3 (sheet 2 of 2)

p . . _. .

70 i i i i i j

l - \

/ \

.i t '1

{ 60- i f

i f AUXILIARY GPPAY I

INITIATED i.

1 y 50 i h i 5 \

I f ul g 40 _.

i _

=

y 'l \

ai t

\

, w \ \

8

- 30 \ -

t OPERATOR  %

OPENS ADV h'q

^ ' ^ '

~

20 - " " ~

l 0

O 5000 10000 15000 20000 25000 30000 TIME,SEC0tlDS o

i Palo Ynde Nudear Gmereting Station FSAR STEAM GEttEPATOR TUBE PUPWPI WITH I453 OF OTFSITE POWER AffD A TULLY SWCK OPDI ATMOSPl{ERIC OUMP VALVE TUBE LEAK RATE VS TIME Figure 1,$A-11 fCheet 2 of 2) l

4

~

\ wI R

E Z

R U

S r

S E

AP R S

H T

A J , "

2 P

s , 3

/ T I 7 N L ,

E V

R E

Z I

R U

a, l S

s l s S E

u - I R

P T l NE ER s s

. ME l ,,

. NH IP AS f L TO NM CT

^ vL J l J vTD R

CA

. t

2...... - . . .

j . i

l. .

1 li

~

PRESSURIZER VENT SYSTEM j DEPRESSURIZATION DURING SGTR i

1 REDUNDANT CLASS 1E QUALIFIED VENT PATHS l

i j -

LIMITING PATH (7/32 INCH ORIFICE) i j

~

hf hkhfbkbR!bhRkkEk h PROVIDES ACCEPTABLE DEPRESSURIZATION PERFORMANCE EMERGENCY OPERATING PROCEDURES ADVISE OPERATOR OF AVAILABILITY OF VENT TO BACKUP PRESSURIZER AUXILIARY SPRAY

,i i

[

4

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

.-.-.u.....

4 W-I EXISTING DESIGN .

r o PRIMARY PATH FOR SAFE SilVTDOWN l

i l o VALVE BY VALVE FAILURE IN PRIMARY PATH l

o

SUMMARY

- MANUAL ACTIONS OUTSIDE CONTROL ROOM i

I I

l I

I l

i i

i

= _ . . . . _ ._-

LETDOWN s -

s s

R

^

Ne x $0h--

< 164 W

H e VOLUME CHARGING k 6'

r filter hh 4 PUMPS _ _

\d 1:757 - -

~

SP AY SORIC ACID dp,OI s MAKEUP

@ 30 ) 4 k \ _

_f3 -;

s

\ /

V k RCS

\

][755 INJECTON L

e hk

~

d W s 4

V S SAFETY INJECTION h' C- AlG \G AUX _l ARY S37AY

. . . . . = - . . . . . ..

'. i OPERATOR ACTION

SUMMARY

, FAILURE MANUAL ACTION V536 IN CLOSED POSITION MANUALLY OPEN V327 AND V757, V756 on V755 l

V501 To CLOSE MANUALLY DEPRESSURIZE VCT, MANUALLY VENT THE CHARGING

PUMPS b

F . .- .. .

CVCS ENHANCEMENT o REPORT OF ACTIONS UNDERTAKEN TO ADDRESS SEPTEMBER 12, 1985 EVENT ( PER SEPTEMBER 20, 1985 MEETING )

o THREE MODIFICATIONS PLANNED ENSURE CONTINUED CONTROL OF V501 AND V536 FOLLOWING LOP AND SIAS ADD SECOND, DIVERSE REFERENCE LEG FOR VCT LEVEL MONITORING WITH ALARM

- AUTOMATIC REALIGNMENT OF V501 AND V536 1

i 0

88*4P '

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

-(

~

VALVE Poller SUPPLY CilAilr,L

-EXISTING- . MODIFIED- ,

l 16 60s !s- Gus rno p )

  1. ^'

)sids ,I NON /E MC C. / E M C c.

\

l 1

T 501 536 5 01 53(o CllANGE ENSURES OPERABILITY FR0f1 CONTROL ROOM AFTER SIAS AND LOP SUCli TilAT SUCTION COULD BE All6NED TO RlIT FR0ft VCl.

~

r r, . , . . . , _ _ . . .m-

  • 't JMI fINild)1 linin i Vi t I Nilli i. i l'If, ExidTING MODIFIED N

'N i VOLUME v0LUME '-~

CONTROL CONTROL CONTROL TANK CONTROL ROOM p- -ROOM INDICATOR INDICATOR

[

l LT-226 226 T-227 ,

I l l l

LOW LOW . _ __ _t LEVEL - S1GNAL SIGNAL LEVEL i~ COMPAPATOR SIGNAL AND CONTROL I ALARM ON ROOM ALARM '-- I"UI LEVEL DicFERENCE R1PR_02 mfg 1 1.

SEPERATE REFERENCE LEG TO EACH TRANSMITTER 2.

ONE kiET AND ONE DRY LEG TO PROVIDE DIVERSE REFERENCf 3.

COMPARATOR AL ARM DROVIDES INDICATI0ti 0F POSSIBLE LO4 -T

, CORRECT RE F F R E rlCE TO ONE OF THE TRANSMITTERS T

me

1

_ LETDOWN ,,

o f%40 z ey -

UZ ><<

64 i2

^

^I--- -

  • VOLUME CHARGING COfiGCL PUMPS

^

h_ O filter

\/

4 I

4(

r c-

]

A lb I w or m ,

x y 3_ _ __

j V

'6- -

l j \ "mm 121 rm Y

I N AUTOMATIC TRANSFER TO REFUELING WATER TANK

- . . . . . . m ENHANCEMENT EVALUATION o BORATED WATER SOURCE REMAINS AVAILABLE TO CONTROL ROOM OPERATOR FOLLOWING LOP AND SIAS o INACCURATE VCT LEVEL IS ALARMED IN CONTROL ROOM o OPERATOR WORK LOAD REDUCED BY AUTO TRANSFER OF V501 AND V536 1

4

.4 I

4 t

I

.

Retrieved from "https://kanterella.com/w/index.php?title=ML20140G813&oldid=2859773"