ML17055C756

Summary of 861218 Meeting W/Util & S&W Re Logic Mods to MSIVs Actuators Due to 861203 Full Scram as Result of Loss of Power to Both Reactor Protection Sys Scram Sensor Busses. Util Design Mods Unacceptable,Per Reg Guide 1.6

ML17055C756
Person / Time
Site:	Nine Mile Point
Issue date:	01/02/1987
From:	Haughey M Office of Nuclear Reactor Regulation
To:	Office of Nuclear Reactor Regulation
References
RTR-REGGD-01.006, RTR-REGGD-1.006 NUDOCS 8701090087
Download: ML17055C756 (36)

Text

January 2,

1987 Docket No. 50-410 LICENSEE:

Niagara Mohawk Power Corporation (NMPC)

FACILITY:

Nine Mile Point Nuclear Station Unit 2 (NMP-2)

SUMMARY

OF MEETING WITH NMPC ON DECEMBER 18,

1986, CONCERNING LOGIC MODIFICATIONS TO THE MAIN STEAM ISOLATION VALVES ACTUATORS AT NMP-2 On December 18, 1986, the NRC staff met with representatives of NMPC and their consultants, Stone and Webster Engineering Corporation (SWEC), to discuss the logic modifications made to the main steam isolation valves (MSIVs) at NMP-2.

On December 3, 1986, a full scram occurred at NMP-2 as a result of a loss of power to both reactor protection system (RPS) scram sensor busses.

This event was caused by an overcurrent resulting from the crossing of loads in the MSIV logic circuit.

Alerted by this event, the NRC requested NMPC to meet with them on December 18, 1986 to discuss the details of the logic modifications to the MSIVs.

During the meeting, NMPC provided details of the MSIV logic circuits for the original MSIV actuators, the modified actuators before the December 3 event, and the modified actuators following the December 3 event.

Logic diagrams and circuit diagrams were provided in a handout from NMPC which is included as en-closure l.

Because the revised MSIV actuator design eliminates the latching mechanism and relies on the hydraulic system to maintain the MSIVs in the open position, an automatic auctioneering circuit was installed on each of the solenoids to reduce the probability of inadvertent closure of the MSIVs.

The hydraulic system sole-noid valves open on loss of power, venting the hydraulic system and allowing the MSIVs to close from unbalanced spring forces.

The automatic auctioneering circuit allows the solenoids to remain energized from power sources from either division, thereby reducing the chance of an inadvertent MSIV closure on loss of power from either division.

While the NRC staff agreed that inadvertent MSIV actuation was undesirable, the staff expressed concern that such an arrangement could permit a transfer of loads across power. supplies.

The NRC also noted that this design was specifically noted as being unacceptable in Regulatory Guide 1.6.

.The staff stated that the design was unacceptable and that NMPC should proceed with determining an alternate design for the MSIV actuator logic.

NMPC questioned what testing of the circuits could be performed to prove that the design was acceptable.

The staff indicated that it could not state what, if any, test program of these circuits could provide the assurance needed to support the proposed logic circuitry.

870 1 090087 870 i02 PDR ADQCK 050004iO P

PDR

%h

'p L

i)

Mr. C. V. Mangan Niagara Mohawk Power Corporation r

Nine Mile Point Nuclear Station Unit 2,

CC:

Mr. Troy B. Conner, Jr.,

Esq.

Conner 8 Wetterhahn Suite 1050 1747 Pennsylvania

Avenue, N.W.

Washington, D.C.

20006 Richard Goldsmith Syracuse University College of Law E. I. White Hall Campus

Syracuse, New York 12223 Ezra I. Bialik Assistant Attorney General Environmental Protection Bureau New York State Department of Law 2 World Trade Center New York, New York 10047 Resident Inspector Nine Mile Point Nuclear Power Station P. 0.

Box 99

Lycoming, New York 13093 Mr. John W. Keib, Esq.

Niagara Mohawk Power Corporation 300 Erie Boulevard West

Syracuse, New York 13202 Mr.'James Linyille U. S. Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, Pennsylvania 19406 Norman Rademacher, Licensing Niagara Mohawk Power Corporation 300 Erie Boulevard West

Syracuse, New York 13202 Don Hill Niagara Mohawk Power Corporation Suite 550 4520 East West Highway

Bethesda, Maryland 20814 Regional Administrator, Region I U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pennsylvania 19406

1300 PSI, MSIV CONVERTED HYDR AULIC S YSTE M ac NC a

a);.e)flp ac Sl!

I I

Le I-L

'%%4~

I I

f I

I I

I t

I I

umaoa SI%l05 ILCN.11I71JH.VCL4I

PR E R E QU IS ITES

~

MSIV NOT OPENING ACT ION

~

TURN CONTROL SWITCH.TO CLOSE

~R".=Uk T

~

DE-ENERGIZE AND OPEN SVC

~

BLOCK START OF MAIN Pl3MP

~

BLOCK START OF JOCKEY PUMP C OMPLET ION DE -ENER IZE AND OPE N SVE -A, SVE -B, SVC

~

DE-ENERGIZE MAIN PUMP

~

DE-ENERGIZE JOCKEY PUMP MSIV CONVERTED HYDRAULIC SYSTEM

'IISBP Ic

'fi-'IBRP I

I Le FS avuauruo ACCJWLATQR I-lCIOATOI S%XQ5 n.oettmsx.vn..e

RPS TRIP TEST

~P ~ ERE >>TRIT

~

MSIV IN FULLY OPEN POSITION

~

CHANNEL I 4 2 CONTROL POWER AVAILABLE

~

NO MANUAL OR AUTOMATIC El1ERGENCY TRIPS

~ACT ON

~

PRESS RPS TRIP TEST PUSHBUTTON RESULT DE-ENERGIZE AND OPEN SOLENOID SVC

~

BLOCK MAIN AjIJD JOCKEY PUl1P STARl MSIV COMMENCES SLOW CLOSURE UNTIL

'RPS TRIP POSITION IS REACHED OR UPON 25 SEC DURATION COMPLETION

~

ENERGIZE 4 CLOSE SOLENOID SVC

~

START MAIN PUMP

~

START JOCKEY PUMP

~

MSIV-RETURNS TO FULL OPEN POSITION o

STOP PUMPS WHEN o

1300PSI MSIV CONVERTED HYDR AUL IC SYSTE M XC bm bC ST!

b

'ti'iNP

'l I

a L>>

N anno uo ACCULIILATCb I-tI.OKItltMKIICL.II

.EMERGENCY TRIP PR ERE QU IS ITE S

" ~

NONE ACT ION

~

PRESS CHANNEL I AND 2 EMERGENCY. TRIP PUSHBUTTONS

-OR-AUTOMATIC ISPLATION SIGNAL RESULT.

p DE-ENERGIZE AND OPEN SVE "A, SVE-B, SVC

~

TRIP AND LOCKOUT MAIN PUMP

~

TRIP AND LOCKOUT JOCKEY PUMP COMPLETION

~

DE-ENERGIZE AND OPEN SVE-A, SVE-B, SVC DE-ENERGIZE MAIN PUMP

~

DE-ENERGIZE JOCKEY PUMP MSIV CONVERTED HYDRAULIC SYSTEM VBP sc kc IC IC N'

ka R4~ egizatc

'l I

IL PS Ieaavuo AONWLATDll l-n.eaamseva.a

RPS /

MSIV POWER SU P PLY A 100 B

100 A 103 D1 RPS A 104 D3 RPS A 110 D4 RPS B 103 D2 RPS B

110 D3 RPS B 104 D4 RPS A 106 DP.

RPS YL-/ W MSIV (D2)

I I

I I

I I

IL A 105 MSIV GREEN (DU I

IL B 105 D1

'PS MSIV GN /1M (D1)

B 106 YELLOW MSIV (D2)

I FLCH.I2 I77.EH.MDL.I3

0 MSIV ORIGINAL POtAtER SUPPLY 8ATIERY BACK-UP BATIERY BACK-UP PREFERRED NORMAL STATION SERVICE ALIERNATE RESERVE STATION SERVICE PREFERRED NORMAL STATION SERVICE ALTERNATE RESERVE STATION SERVICE UPS 3A

'PS 3B EPA EPA NON"1E NORMAL POWER SOURCE EPA PNL A100 NON-lE CLASS" 1E EPA PNL 'B100 NON-1E NORMAL POWER SOURCE

'NL A105 PNL A106 PNL B106 PNL B106 OUTBOARD LOGIC PANEL INBOARD LOGIC PANEL BLACK GREEN GREEN / WHITE NON"1E CHANNEL I CHANNEL 2 YELLOW CHANNEL 1 YELLOW/WHITE BLACK CHANNEL 2 NON-1E A

SFA 8

SFB A

SFA SVA B

SFB OUTBOARD -MSIV S INBOARD MSIV S FLCH. I2 I77.E H.MDI..O7

1

MSIV MODIFIED POtAtER SUPPLY BATTERY BACK-UP BATTERY BACK-UP PREFERRED NORMAL STATION

SERVICE, ALTERNATE RESERVE STATION SERVICE PREFERRED NORMAL STATlON SERVICE ALTERNATE RESERVE STATION SERVICE UPS

.3A UPS 3B

, EPA EPA NON"1E BACKUP POWER SOURCE I

EPA PNL A100 NON-1E CLASS 1E EPA PNL B100 NON-1E BACKUP POWER SOURCE I

I PNL A106 ISO L ON PNL A106 PNL B105 ISOLATION PNL B106 I

I I

I II.

I

)

I OUTBOARD. LOGIC PANEL INBOARD LOGIC PANEL BLACK 'REEN NON"1E,:, CHANNEL 1

I i5 GREEN / WHITE CHANNEL 2 YELLOW YELLOW/WHITE CHANNEL 1 CHANNEL 2 BLACK NON-1E I

I I

SVE I

A OUTBOARD MSIV S SVE B

SVE A

I I

I SVE I

I B

I INBOARD MSIV S FLCk.12177.EH. MOL.O8

e

MSIV TRANSFER CRUITRY POS CR7 CREO CHANNEL 1 UPS POWER OPEN PERMISSIVES

'H SEAL H

i

~

CLOSE PERMISSIVES SEAL IN CIj7 SEQ NORMAL OPEH-I CLOSE RELAY (NORMAL -

SLOVO CHANNEL 1

EMERGENCY

~PS / RESET CR1 0%

0A EMERSEHCY TRIP/

FAST CLOSE RELAYS SEAL IH OR4 01$

CRSr-- a SVE A

L J

OR4 NORIIAL TRIP ISLOW CLOSE)

OKAHHEL 1 EMER TRIP SOI.

CHANNEL V2 TRANSFER CR 4

CR7 CR 4A OR BA CR SA CHANNEL 2 UPS POWER CR CR SA 16 CR CR SA 4A CR CR 7

CR4A r

\\

SVE B ~ J CR4A CHANNEL 2 EMER TRIP SOL CHANNEL 6 EMERGENCY TRIP6 / RE6ET I

J CR37 LSEAL IH CI iA CRli CR CC EMERGENCY T)IIP/

FAST CLOSE RELAY6 (CIL2)

NON-lE CHANNEL POS ORBS ORS RPS lEST TRIP 00II OR38 ORB r

l OR3 CRB NORMAL

'NORMAL RP6 TEST TRIP

'TRIP TRIP NEO NON-lE TRAN8FER RELAY NORMAL/TE8T TRIP 8OL CRBS NON-lE BACKUP POWER SOURCE (BLACK)

FLCH.I2I77ZHiMDLo04

C 0

4

UNINTERRUPTIBLE POSER SUPPLIES NORMAL SUPPLY D.C.

RECT BACK-UP SUPPLY 126V D.C.

ALTERNATE I

l SUPPLY I

INV I

I I

I I

I I

I I

I I

I STAllC TRANSFER I

I I

I

'I I

I I

I I

I I

UPS 3A NORMAL SUPPLY D.C.

RECT BACK-UP SUPPLY ALTERNATE SUPPLY I

INV I

I I

I I

I I

I I

I I

I STATlC TRANSFER I

I I

I I

I I

I I

I I

I UPS 38 TO MSI LOGIC T= 0-T= 0+

T= 0+

PLANT TRANSIENT UPS 3A 132V++ ALTERNATE SUP P LY RELAY RACE, CROSS CONNECT UPS BLOWN FUSE, INPUT LEG STATIC SW.

TRANSFER TO ALT. A.C.

EPA

TRIP, OVERVOLTAGE UPS 3B; LOSE ALT. A.C.

INVERTER FUSE EPA

TRIP, UNDER-VOLTAGE FbCH.I2I77,EM.MQ.Od

NMEHMDL02

SUMMARY

~

PRE-OP TESTING IN PROCESS CONFIRMING DESIGN

~

MSIV RELIABILITY FEATURES HAVE BEEN MAINTAINED AND ENHANCED

~

MSIV STROKE TIMING CONFIRMED

~

MSIV MECHANICAL LATCH PROBLEMS OVERCOME

~

MSIV ACTUATORS HAVE BEEN SUCCESSFULLY CONY.ERTED

~

~

12/18/86 MSIV LOGIC MEETING ENCLOSURE 2 NAME Mary Haughey Peter Francisco Donald Hill M. Srinivasan C. Marschall J.

C. Linville Bob Stevens Jim Bunyon E. J.

Hubner C.

E. Crocker J. J.

Panchison ORGANIZATION NRC Niagara Mohwak NMPC - Licensing NRC/DBL/EICSB NRC/Resident Inspector, NMP NRC RI Section Chief, DRP NRC/EICSB/DBL/NRR NMPC Engineering Stone 5 Webster SWEC SWEC

0 h

January, 2, 1987 MEETING

SUMMARY

DISTRIBUTION

~Docket No.(s).:

50=4100 NRC PDR Local PDR BMD k'3 r/f J. Partlow E.

Adensam

Attorney, OGC E. Jordan B. Grimes ACRS (10)

Project Manager M. Hau hey E. Hylton NRC PARTICIPANTS Mary Haughey M. Srinivasan C. Marschall J.

C. Linville bcc:

Applicant

& Service List

V