|

w

U.S. NUCLE AA f<EOULATORY i,Oi==siteSIONesRC Fwe 3se# APPROVED OMS NO.3190-4104#

''*REs. Si3uesLICENSEE EVENT REPORT (LER)

DOCKET NUMSER (2) PAGE(3FACILITV NAast til

Brunswick Steam Electric Plant Unit 1 015 | 0 | 0 | 0 l 31215 1|OF|013Unit i Reactor Scram and Unit 2 Reactor Protection System Actuation Resulting From" ' ' ' ' ' '

Lichtnine Strikes Durine inclement Weather Activity Preceding Hurricane Diana.SvtNT DATE IS) LER NUnaeER 643 REPORT DATE 171 OTHER F ActLITIES 6 fv0LVEO tel

8,E {E MONTH DAY YEAR F ACILITV Nawts OOCKET NUMEERl53MONTH QAY YEAR YEAR 8 E,0 '"b

, : s

Brunswick Unit 2 0 | 5101010131214

0|9 1| 0 8 4 8|4-

0 |2 | 5-

0|0 1| C 1|0 8| 4 0 t 5|0 1 0 1 0 t i ITHIS REPORT 18 $USMITTED PURSUANT TO THE REQUIREMENTS OF to CPR $: (Chere one or sao,e of ene feireemps 111)

OPERATINGMODE W | 20.40219) 20 40 Sis) X 30.73teH2) tivi

_73.71(b)

20.405tal(1HQ to.3sleHti 30.73(aH2Hv) 73.71(a)R ,

_

0-nHv.,_ = ,3.g 7 ,,999 .0...,=>

1 a.O.wiH.i_ _

J56AJ

nel

20.40siaH1Hieil 50.73(alcH0 50.73(aH2Hvi44HAl

20 400laH1H8vl 60.73(aH2He) 80.73(aH2|lvtulIS)i - - -

M405(sit 1Het 50.734el(2ltiid 90.73(aH2Hm!

LICENSEE CONTACT FOR TMig LER |12|

NAME TELEPHONE NUMSER

ARE A COQE

M. J. Pastva, Jr., Regulatory Technician 91119 415171 -1915 | 2| ICOMP.ETE ONE LINE FOR EACM COMPONENT FAILURE DESCRIGED IN THIS REPORT 1133

O Np'n" M ' ""#" " "

CAUSE SYSTEM COMPONENTCAUSE SYSTEM COMPONENT E tO PR 5TV E

X I;J ; I Z| 1 N;0 | 6|8 No [ , , , ; , , m

I I I I I l | | | | | | # | ' MeSUPPLEMENTAL REPORT EXPECTED 114e MONTM OAY YEAR

susuissioN

YES fit yes, cono,ese EXPECTED SUSA,ISSION DATEJ NO | | |ATACTm,,,,,,.,.o0,,,..,,,,,,,,,,,,e,,,,,,,,,,,,,,,,,,n.i

On 9-10-84, at 0909, a Unit 1 automatic reactor scram and a primarycontainment Group 1 isolation occurred due to an instrument upscale actuationof Unit I reactor main steam line radiation high monitors 1-D12-RM-K603C and D.At the time, Unit I was at 99 percent power. At 0915, on 9-10-84, the Unit 2Reactor Protection System (RPS) automatically initiated due to a neutron fluxhigh signal to the reactor average power range monitoring system. At thetime, Unit 2 was in a refuel / maintenance outage.

The events resulted from lightning striking the units' common Turbine Buildingstructure heater bay semigantry crane and common electrical switchyard area,which induced electrical impulses into each unit's subject instrumentation. I,

l1

After the Unit 2 event, the RPS trip signal was reset. During the Unit 1scram recovery, reactor level briefly decreased to low level No. 1. The unit

High Pressure Coolant Injection and Reactor Core Isolation Cooling Systemsautomatically started but did not inject. Reactor safety relief valve (SRV)F013G automatically lifted at the highest reactor pressure of 1105 psig, andSRVs F013A and E were manually opened to control reactor pressure. No sonicindication of SRV positions was available, although the SRV tailpipetemperature indicators were functioning properly.

Following passage of Hurricane Diana, subsequent reactor criticality on Unit Iwas established on 9-15-84.

f 22 ;/l l8410180587 841010PDR ADOCK 05000325S PDR|;,i'" "*

y --

h.

U S. NUCLEfM LEGULAToMY Cossamm40es*ameC Fem se64'""

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION Areaovio oue No mo-cio.* smeians. enon

FACILITY NAast (H DOCKET NuteSER Q) ggn gyggggg g$) PAGE (31

'I '[,'' . ::[, gy,'VEAR

|

Brunswick Steam Electric Plant Unit I o|5|0|o|0|3|2|5 8| 4 -- O | 2| 5 -- 0|0 0|2 OF 0 |3 |hat,n . -4 =-w=ca- mwwnn j

!

On September 10, 1984, at 0909, a Unit 1 automatic reactor scram with a iPrimary Containment Isolation System (PCIS) Croup 1 isolation occurred. An )

_ assessment of appropriate Unit 1 Control Room indications and alarm'

annunciations determined the event resulted from an instrument upscaleactuation of the unit reactor main steam line radiation high monitors1-D12-RM-K603C and D. These instruments respectively provide A2 and E2 logicchannel input to the Reactor Protection System (RPS) and the IsolationActuation Instrumentation System. At the time of this event, Unit I wasoperating at 99 percent power. Later the same day at 0915 an automaticinitiation of the Unit 2 RPS occurred. An assessment of appropriate Unit 2Control Room indications and alarm annunciations determined the event resultedfrom a high neutron flux signal to the Reactor Average Power Range Monitoring(APRM) System. At the time of this event, Unit 2 was in a refueling /maintenance outage.

These events resulted from lightning strikes during inclement weather activitypreceding Hurricane Diana. Lightning struck the units' common TurbineBuilding structure heater bay semigantry crane and areas within the units'common electrical distribution switchyard. It is believed the incurredlightning strikes caused electrical impulses to be induced into the electricalcircuitry of the subject instrumentation, thereby resulting in each event.

Shortly after the Unit 2 event, the incurred RPS trip signal was reset.

Following the Unit I reactor scram, a reactor scram recovery was carried outin accordance with applicable plant procedures. During the scram recovery,reactor level briefly decreased to the reactor low level No. I setpoint of2 162.5 inches. The unit reactor High Pressure Coolant Injection (HPCI)System and Reactor Core Isolation Cooling (RCIC) System automatically startedbut did not inject to the reactor because the low level No. I condition didnot exist long enough for the required 3-6 second injection permissive toseal-in. Reactor safety relief valve (SRV) 1-B21-F013G automatically openedat the highest recorded reactor pressure of 1105 psig. SRVs B21-F013A and Ewere manually opened to control reactor pressure. In addition, during thescram recovery sonic probe position indication of the subject SRV automaticand manual opening did not function, although respective SRV tailpipeindications of valve openinga were operable.

Following the Unit I reactor scram recovery, an actuation setpoint check and afunctional test of the subject SRV sonic position indicators were performedwith no problems found.

,o. m.

-

a j

p.,gg4Fenn 30eA . u.s IvycLEA A REGLLArORY COesamessoas ]' ' " '

)LICENSEE EVENT REPORT (LER) TEXT CENTINUATION arraovin ow wo. nno-evos. exeiams smes i

..ciur, a.= ni oocan auwaa m t. . u . ,,, emos m

a:=m - =: ;...-

Brunswick Steam Electric Plant Unit 1 o |5 |0 j o lo | 3|2 | 5 8| 4 -- 0| 4 5 -- 0 |0 0|3 0F 0| 3ruxt <n w ma."ec e assaw nn

The Unit 1 SRV Acoustic Monito' ring System (SRVAMS) was checked electrically byinducing a signal at the system instrumentation signal pre-amps in the Reactor

. Building and the SRVAMS response to acoustic signals was also checked. .Bothchecks indicated proper system operation. The initial SRVAMS startup data wasalso reviewed and it was discovered that an important correlation batweenacoustic levels at 250 psig Reactor Pressure and 1000 psig Reactor Pressurewas overlooked.

~

The initial setpoint of the SRVAMS was 250 millivolts as indicated on thesystem fluid flow detector (FFD) modules. This setpoint was selectedarbitrarily based on system acoustic levels recorded during SRV actuation at250 psig, Reactor Vessel Pressure. Since recorded maximum acoustic levelswere 900 mV-1100 mV for all valves and the maximum valve crosstalk wasapproximately 30 mV, 250 mV was selected as an acceptable value. Threc I3)

.

valves were rested during system startup at 1000 psig reactor pressure whileall the valves were tested at 250 psig reactor pressure. Correlating thethree (3) valves tested at 1000 peig with their 250 psig test revealed adrastic SRVAho output decrease at the 1000 psig SRV test. This decrease wasto a value of approximately 1/5 initial 250 psig SRV test. This decrease canbe explained due to a shift in the acoustic signal frequency content due tothe higher steam flow velocities at 1000 psig. Since the acoustic detectorsdo not have a flat response spectrum but centain peaks at various frequencieswith a resonants' frequency between 20-25 KHZ, this behavior can be explained.Also since each detector has its own response spectrum, some decrease whileother channels may not decrease hardly at all. This was also observed whilereviewing the initial SRVAMS startup data.

These results were confirmed with Philadelphia Electric Peachbottom Plantwhich has a system similar to Carolina Power & Light Company but with longeroperational history.

Based on the above, a 100 mV setpoint was chosen to provide more reliable SRVopen indication. This setpoint was implemented on Unit 1 following the unitscram recovery. Following the subsequent startup of Unit 1 on September 15,1984, one Unit 1 SRV was tested and proper SRVAMS operation was observed.Appropriate plant procedures will be revised as required to reflect the newSRVAMS setpoint and enable a more accurate test of the SRVAMS operation.

The subject SRVAMS setpoint will be implemented on Unit 2 prior to completionof the ongoing Unit 2 refueling / maintenance outage. !

l

I1

|||

F0mW 3esa

:

|-

~. ._ .

7-

l

.,.

CP&L-

|'Carolina Power & Light Company

. ..t

Brunswick Steam Electric PlantP. O. Box 10429

Southport,'NC 28461-0429

October 10, 1984

FILE: B09-13510CSERIAL: BSEP/84-2103 -

NRC Document Control DeskU.S. Nuclear Regulatory CommissionWashington, M 20155

BRUNSWICK STEAM ELECTRIC PLANT UNIT 1DOCKET NO. 50-325LICENSE NO. DPR-71

LICENSEE EVENT REPORT 1-84-25

Gentlemen:

In accordance with Title 10 to the Code of Federal Regulations, the enclosedLicensee Event Report is submitted. This report fulfills the requirement fora written report within thirty (30) days of a reportable occurrence and is inaccordance with the format set forth in NUREG-1022, September 1983.

Very truly yours,-

0iqC. R. Dietz, General ManagerBrunswick Steam Electric Plant

MJP/sd1/LETSDL

Enclosure

cc: Mr. R. C. DeYoungMr. J. P. O'Reilly

'//