ML20140G809

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Forwards 850825 Morning Rept on Tube Rupture & Steam Line Breaks.Incident May Indicate Need for ACRS to Reflect Further on Proposed Primary Blowdown Concepts for Pwrs. Viewgraphs Encl
ML20140G809
Person / Time
Site: Palo Verde, 05000000
Issue date: 09/11/1985
From: Reed G
Advisory Committee on Reactor Safeguards
To: Wylie C
Advisory Committee on Reactor Safeguards
Shared Package
ML20140B723 List:
References
FOIA-86-45, FOIA-86-47 NUDOCS 8604030595
Download: ML20140G809 (18)
v • d • e


Text

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o UNITED STATES NUCLEAR REGULATORY COMMISSION 3 .I ADVISORY COMMITTEE ON REACTOR SAFEGUARDS

%...../ September 11, 1985 MEMORANDUM FOR: C. Wylie, Chairman, CE System 80 Subcormiittee o ACRS Members FROM:

G.A. Reed [

SUBJECT:

Attached Morning Report on Palo Verde Incident You are acquainted with my position that the Palo Verde (CE System 80) units had " lean" systems as far as assured core cooling was concerned and that my opinion favored the inclusion of a PORV system. (ACRS letters in

. the past have expressed concern about the noninclusion of PORVs in the i System 80 design.) The attached Morning Report of August 25, 1985 indi-cates to me that reliance by CE on Auxiliary Feed Pumps (in the configura-tion at Palo Verde) for the accidents of tube rupture and steam ifne breaks (wherein.the need for primary depressurization and assured core cooling becomes complicated) should be further reviewed on an urgent basis.

In my opinion, this Palo Verde incident may also be a precursor indicating a need for ACRS to reflect further on my proposed primary blowdown --

redundant in principle -- concepts for some PWRs.

Attachment:

as stated cc: J. Flack i

I l

l 8604030593 860311 PDR FOIA SCOTT 86-4 d PDR

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  • MORNING REPORT - REGION V .

DATE: AUGUST 25, 1985

  • REGIONAL ACTION NOTIFICATION ITEM OR EVENT FACILITY FOLLOWUP PER MC 25t5 FAX FROM SENIOR BECHTEL NOTIFIED THE LICENSEE THAT AN ENGINEERING' ARIZONA PUBLIC EVALUATION HAS SH0HN THAT A MAIN STEAM LINE BREAK SERVICE COMPANY RESIDENT INSPECTOR IN THE MAIN STEAM SUPPORT STRUCTURE COULD RESULT
  • PVNGS 81 IN TH0 AUXILIARY FEEDHATER (AFH) PUMP ROOMS BEING DN 50-528 7 PRESSURIZED TO APPROXIMATELY 20 PSIG AND 260 F 'e

'I / 7- -;

'TC).

DEGREES. THE LICENSEE HAS DECLARED BOTH PUMPS INOPERABLE BASED ON THE PUMPS AND ASSOCIATED

'7 INSTRUMENTATION NOT BEING QUALIFIED FOR THE REVISED, -

A*SUMED ENVIRONMENTAL CONDITIONS. PALO VERDE 1 HILL jf # ROMAIN IN MODE 4 UNTIL CONDUIT SEALANT (HHICH IS THE c eul7dIdd 'I)[/

W 4 j~[gg MEANS BY HHICH THE STEAM HOULD BE COMMUNICATED INTO I

m THE AFH PUMP ROOMS) IS UPGRADED TO PREVENT LEAKAGE.

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3 FOLLOWUP PER MC 2515 -

FAX FROM SENIOR THE LICENSEE N/.S NOTIFIED BY COMBUSTION ENGINEERING ARIZONA PUBLIC THAT AT PALO VERDE 1 THE VARIABLE SETPOINT (VSP)

SERVICE COMP RESIDEyT INSPECTOR CARDS ASSOCIATED HITH THE VARIABLE OVERPDHER TRIP PVNGS 81 '

j (V0PT) RATE CIRCUIT IS SUBJECT TO RANDOMIFSETPOINT DN 50-528 /) A RANDOM s / FLUCTUATIONS AT VARYING POWER LEVELS.

SETPOINT INCREASE HERE TO OCCUR SIMULTAMEOUS HITH A

- CONTROL ELEMENT ASSEMBLY EJECTION, THE ACCIDENT

'" ANALYSES MAY BE VIOLATED. THE UNIT IS CURRENTLY

, ,,r" SHUTDOHN AND HAS BEEN SINCE JULY 24, 1985, TO PERFORM VARIOUS MAINTENANCE ACTIVITIES. THE LICENSEE HAS MODIFIED THE VSP CARD IN ACCORDANCE NITH CE RECOMMENDATIONS TO PREVENT A SETPOINT FLUCTUATION.

OPERATIONAL RESTRICTIONS PROPOSED BY CE HILL ALSD BE IMPLEMENTED UNTIL THE MODIFIED CIRCUITRY HAS BEEN TESTED.

FOLLOWUP PER MC 25f2 TELEPHONE CALL FROM PDTENTIAL 50.55(E) AND PART 21:

ARIZONA PUSLIC CE HAS IDENTIFIED MONCONFORMANCES CONCERNING 4

SERVICE COMPANY LICENSEE AT 2:00 PM DN 08/21/85 STAINLESS STEEL FLEXIBLE CONDUIT ON CE SUPPLIED PVNGS 828S INSTRUMENT RACKS AS INSTALLED IN UNIT 2. THESE DN 50-529 ..

NONCONFORMANCES INCLUDE VIOLATION OF MINIMUM SEND

- 50-550 RADIUS CRITERI A, DAMAGED CONDUIT, LOOSE FITTING I

NUTS, ONE DISCONNECTED END FITTING. (DER 85-28) i

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

, _1.

K ANPP/NRC MEETING T0 DISCUSS PVNGS AUXILIARY SPRAY CAPABILITY AND THE STARTUP TESTING EVENT OF SEPTEMBER 12, 1985 1

i I. INTRODUCTION J. G. HAYNES V. P. - NUCLEAR PRODUCTION II. SEPTEMBER 12, 1985 EVENT 1) R. E. G0UGE

, UNIT 1 DAY SHIFT SUPV.

2) D. D. SWAN UNIT 1 ASST. SHIFT SUPV.
III. AUXILIARY SPRAY DESIGN / T. F. QUAN I

LICEf1 SING COMMITMENTS LICENSING SUPERVISOR l

IV. EVEllT EVALUATION T. F. QUAN '

V. CONCLUSION J. G. HAYNES V. PP- NUCLEAR PRODUCTION n

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

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CONDITIONS PRIOR TO EVENT OF 9-12-85 1.

REACTOR AT 53% FULL POWER

2. TURBINE GENERATOR ONLINE AT 585 MWe
3. PREPARING FOR 50% LOSS OF LOAD TEST t

PURPOSE OF 50% LOSS OF LOAD TEST:

1 y

1. DEMONSTRATE THAT THE PLANT CAN ACCOMMODATE A LOAD REJECTION FROM 50% POWER
2. VERIFY THAT THE TRANSIENT DID NOT IlllTIATE A REACTOR POWER CUTBACK f

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._ . ; ~ =..= :... .. .: . . . .

SEQUENCE OF EVENTS 2208 TEST INITIATED BY REMOTE MANUAL OPENING OF BOTH GENERATOR OUTPUT BREAKERS. (TURBINE-GENERATOR FLUCTUATIONS) 2209 REACTOR TRIP (FLOW-PROJECTED DNBR TRIP FROM CPC) 2209 TUR3INE TRIP (CAUSED BY REACTOR TRIP) 2215 NON-SAFETY RELATED AUXILIARY FEEDWATER PlNP STARTED 2217 ATMOSPHERIC DUMP VALVES (0NE ON EACH STEAM GENERATOR)

OPENED 3%

2218 MAIN STEAMLINE DRAINS AUTOMATICALLY RE0PENED UPON RESTORATION ON NON-1E ELECTRICAL POWER 2222 SIAS AND CIAS INITIATED (1837 PSIA; 540 F)

SIAS AND CIAS ACTUATIONS WERE VERIFIED AS PER DESIGN WITH HPSI INJECTING APPR0XIMATELY 75 GPM TO EACH COLD LEG 2223 NOTIFICATION OF UNUSUAL EVENT DECLARED DUE TO COMPLICATED REACTOR TRIP AND INITIATION OF A SIAS 2225 AUXILIARY OPERATOR RE-ENERGIZED MOTOR CONTROL CENTER NHN-M-72 UNDER CONTROL ROOM DIRECTION (RE-ENERGIZED CHN UV-501, VCT OUTLET AND UV-536, RWT HIGH SLCTION TO CHARGING PUMPS )

Il-2

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.. ..: . .z.; :: . . . . .-.. ..... . . .. .

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1 SEQUENCE OF EVENTS (CONT.)

i

, 2237 CHARGING HEADER LOW FLOW ALARM (40 GPM)

, INTERMITTANT CHARGING HEADER PRESSURE ALARMS FOR THE NEXT 43 MINUTES, OPERATORS WERE ATTEMPTING TO REESTABLISH CHARGING PUMP SUCTION FROM:

(1) RWT HIGH SUCTION VIA CH UV 536 (2) RWT LOW SUCTION VI A CHN V 327

(3) RWT HIGH SUCTION VIA UV 532 -- BAMP CH 514 TO THE CHARGING PUMPS (AFTER NON-1E POWER RESTORATION)
2320 REESTABLISHED CHARGING FLOW WITH TWO CHARGING PLMPS INJECTING 44 GPM TO RCS 2358 RESET SIAS AND CIAS (RCS PRESSURE AND INVENTORY l STABLE AND UNDER CONTROL) 0102 9/13/85 TERMINATION OF NOTIFICATION OF UNUSUAL EVENT l

II-3 8

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CHRONOLOGY OF AUXILIARY SPRAY DESIGN / LICENSING CRITERIA PRE RSB5-1 ORIGINAL DESIGN i

1978 RSB5-1 ISSUED, SYSTEM UPGRADED TO MEET l CLASS 2 PLANT REQUIREMENTS -- REDUNDANT AUX SPRAY VALVE B

2ND OTR,

1981 0440.6 SUBMITTED BY THE NRC ON CESSAR/

PVNGS DOCKETS A6 m'l #5 * "'fW an; .ut h: mb, i B s S 10/8/81 CESSAR RESPONSE TO 0440.6 SUBMITTAL > beva c.y^^%(44 i

8 u cu,a h pp m L.Z o.M c.ma w y'.t )st vp' i r 10/29/81 CESSAR COMMITS TO UPGRADE CH-141 AND 1

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" La y CH-501 w y~ g t uwp,~ y pvuw.-  %,

l E ik j S 11/3/82 #

" SAFETY GRADE AUXILIARY SPRAY SYSTEM" sbh** ,

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.. 1 z

7/28/83 -

"SA'FETY-RELATED METHOD FOR RAPID } [<<y' h{'s DEPRESSURIZATION ... CONSISTENT WITH ?l' ,

4., s THE RECOMMENDATIONS OFi RSB5-1 } ,.

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STATED CEN-239 APPLICABLE TO PVNGS

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. SUBMITTED CEN-239, SUPPLEMENT 3 "' . r.' ; ..

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, CHRONOLOGY OF AUXILIARY SPRAY (CONT.)

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4/27/84 -

NRC LETTER REQUIRiflG AtlALYSIS ASSUMitlG

%% IN%g N

h $%s f rz FULL OPEf! ADV FAILURE k

05E uA 4 F, 7t2 c u k %.u 9 4 N i  !ES 9/1/84 -

PLANT-SPECIFIC SGTR + LOP + FAILED w )%a bR ca-EE ADV ANALYSIS SUBMITTED Y.'

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ORIGINAL AUXILIARY SPRAY CRITERIA i

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! OPERATOR CONTROL OF THE RCS PRESSURE DURING i

FINAL STAGES OF C00LDOWN (WHEN PRESSURE LESS THAN l REQUIRED FOR RCP) AND FOR C00LDOWN OF PRESSURIZER.

i CURRENT AUXILIARY SPRAY CRITERIA i

l SAFETY GRADE PLANT C00LDOWN CONSISTENT WITH l THE GUIDANCE OF BTP RSB 5-1. FOR CLASS 2 PLANTS:

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l 3 OPERATOR ACTIONS OUTSIDE CONTR N

o OPERATOR ACTIONS INSIDE CONTAINMENT  %

AFTER SSE IN o- REMAINING AT HOT STANDBY UNTIL MANUAL l ACTIONS OR REPAIRS ARE COMPLETED.

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i l- Alg SPRAY SYSTEM ACTIVE COMPONENTS f

SPRAY VALVES l

i LOOP ISOLATION VALVES CHARGING PUMPS [ y f 7 A )

DETAILED DESCRIPTION IN RESPONS:'. TO 440.6 wl - on,n ,) . c.0.

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AUX SPRAY SYSTEM i CESSAR vs PVNGS o PVNGS liAS REMOVED INTERNALS FROM

[ MAIN SPRAY BACKFLOW CHECK VALVE i

o PVNGS HAS MODELED AUX SPRAY IN s

) TRANSIENT ANALYSIS OF CERTAIN SG 1 TUBE RUPTURE TRANSIENTS 3

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AUX SPRAY USE IN SAFETY ANALYSES e DURING LONG-TERM C00LDOWN PHEE FOLLOWING EVENT:

j CESSAR-F PVNGS-FSAR (0RIGINAL)

ALL WITH LOP ALL WITH LOP

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e DURING SHORT-TERM MITIGATION. 1 PHASE OF EVENT: . b" CESSAR-F  %/ $

PVNGS-FSAR(AMEND 14) gg9

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NONE SGTR/ LOP / FULL OPEN (5 \' i

[h\ YMy c .,.

FAILED ADV

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PVNGS-FSAR (APPENDIX 15A)

SGTR ANALYSIS RESULTS

SA R EST MATED *

' EYf31 IIE TilV Kfri DOSE THY (U U UJ5E (SECONDS) LREM) UREM) hubKOPENADV 0 0 0

. LOP 51 0 0 bhACT/AFFECTED) 122/132 0 0 1 ADV OPENS 460 0 0 1

MSIS 513 SIAS 581 AFW OVERRIDE 655 AUX SPRAY 1015 115 115*

H!5?eReD 1385 182 18s-2 JR DOSE  !

a -AB 7200 200 210*  ;

l

  • ESTIMATED DOSE DASED 03 REMOVAL OF EFFECT OF AUX SPRAY FL0ll.

. (REGULATORY DOSE LIMIT 300 REM) j l

111-8  !

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I EVENT EVALUAHOR l

LTflL1 - LOSS OF .VCT LEVEL l

COMPENSATORY MEASURES - tiONITOR REFERENCE LEG WATER LEVEL 4G%6y - ALIGN REFUELING WATER TANK TO CHARGING PUMP SUCTION PROMPTLY ON LOSS OF POWER * %.4

- INSTITUTE PROCEDURAL CAUTIONS k ON RESTART OF CHARGING PLNPS t

ITEM 2 - LOSS OF POWER TO CVCS VALVES (501, 536) t COMPENSATORY MEASURE - ALIGN REFUELING WATER TANK TO CHARGING PUMP SUCTION PROMPTLY ON LOSS OF POWER l

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[ Page 1 of 2 Sequence of Events

,j PVNGS Unit 1 September 12, 1985 gg$ ,,,d

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.4 Prior to neart of the load rejection test. 525 KV BKR FL 915 (one of two main generator output breakers) was opened per the test procedure.

4

.IIG DESCRIPTION
22
08:29 Generator output breaker PL 918 was opened from the

{ control room to start the test. '

1 ,

j -

22:08:30 Fast closure of the main turbine control and

intercept valves.

1 ,

! 22:08:31:254 Turbine trip "first in" indication was "No ESTV Press trip" (no electric trip solenoid valve j pressure) - turbine trip was not expected to occur, I

troubleshooting ongoing.

1 22:08:53:721 Low DNBR trip on Channel A - CPC projected low flov causing DNER 22:08:53:738 Low DNBR trip on Channel B - reactor trip signal

22
08:53:796-808 Channel A - D trip breakers opened 22:09:45 TWPI '*A" tripped on low control ofi pressure. The '

, control oil pump is supplied from nonesuential power 22:10:51 Main Eenerator exciter tripped 22:10:53 circulating water and condensate pumps trip - test configuration prevented fast transfer.

22:10:58 Main steam line drain valves are msnually shut - auto opened on turbine trip, per design 22:15:10 Nonclass AFV pump started to maintain SC levels 22:17:42 Manually opened ALV on SC2 to dump steam to atmosphere to prevent degrading vacuum and insure adequate delta T for natural circulation f

22:l8:36 ADV on SG1 manually opened 22:19:07 ADV on SC2 manuaAly closed 22:19:37 Main stean line low point drain valves open

' automatically when nonessential power is restored with turbine trip sigcal present 1 22:21:07 ADV on SC2 manually reopened

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l Page 2 of 2

[ Sequence of Events

{ PVNGS Unit 1

September 12, 1985

! 22:21:38 SIAS/CIAS on low pressurizer pressure (1837 psig).

Nonclass AFW pump shed, "B" AFW pump starts but is i

not used to add water due to SG 1evels being in l normal band. Pressurizer prestare low point is 1819 i

psig.

} 22:23:28 ADVs manually closed t .

l 22:23 Unusual Event declared by S/S based on Rx trip and SIAS/CIAS

e 22:32:05 Established boric acid makeup pump flow to charging f pumps via RWT following gas binding of pumps i 22:33:01 Established RCP seal injection i

22:33:47 Established charging flow to ECS Approx 24:00 Pressurizer LVL back in norcal band L i .

Approx 00:50 Started RCPs 01:03 Terminated Unusual Event i RZ:sh i

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204,6 TIME (SEC ) -) 1806,6 P'Est ifCS TEST 501055 Of LOAD M6 ElFFETd SSCWSEC TESTDATE: 12-SEP-85 SIMIIIE: 21:52:33,6 o P106 HINI M 1819,65 PSIA F106 HAXI M 2363,21 FSIA Ai 1684.6 SEC AT S24.0SEC ilE: 228,571SEC/ DIVISION F106 67,315 PSIA / DIVISION P0INTS PL0iiED FFaiEVERY 16 SCAWS

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