ML19332D518

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LER 89-018-01:on 890515,RCIC Received Div I & Div II Isolation on RCIC High Steam Line Flow.Caused by Spurious High Steam Flow Signal When Steam Added to RCIC Steam Line. Special Test Initiated.Isolation Logic reset.W/891122 Ltr
ML19332D518
Person / Time
Site: LaSalle Constellation icon.png
Issue date: 11/22/1989
From: Diederich G, Tennyson M
COMMONWEALTH EDISON CO.
To:
Office of Nuclear Reactor Regulation
References
LER-89-018, LER-89-18, NUDOCS 8912040076
Download: ML19332D518 (7)
v • d • e


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' Commonwealth Edison LaSalliCountyNuclear Station

.4i 4i Rural Route #1, Box 220 Marsellies,lilinois 61341

, Telephone 815/357-6761 November 22, 1989 i

Director of Nuclear Reactor Regulation  !

' U.S. Nuclear Regulatory Commission  ;

Mail Station F1-137 3 P Washington, D.C.-20555

Dear Sir  :

Licensee tvent Report #89-018-01, Docket #050-373 is being s,ubmitted to your office to supercede previously submitted Licensee Event Report 89-018-00. .

7 NO f G. J. Died rich (Station Manager LaSalle County Station GJD/99tT/kg 3 Enclosure 1

xc: Nuclear Licensing Administrator

' NRC Resident Inspector l NRC Region III Administrator INPO - Records Center

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LICENSEE EVENT REPORT (LER) , g Docket thster (2) Pane (3)

Facility Name (1)

%11e County Sutton Unit 1 01 51 01 01 01 31 71 3 1lofl0l6 ,

i Title (4)

Reactor Core Isolation Coolina isolation Durina Wamue Out to Spurious Hloh 5 tem Flow Sienal nacart Dato (T) Other Facilities involved (8) )

j- Event Date (5) LIR thseer (6)

Year /// Sequential / Revision Month Day Year Facillty Names Docket thster(s)

Month Day Year l ffj

/// thster l//j/

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01 51 01 01 01 I I 01 5 11 5 81 9 81 9 01118 01 1 111 21 2 61 9 01510101of I I l; l

THIS REPORT 15 $UBMITTED PURSUANT TO THE REQUIREMENTS OF 10CFR '

(Check one or wwe of the followine) (11) )

MODE N 1 20.402(b) _

20.405(c) .jL 50.73(a)(2)(lv; _ 73.71(b)

J 20.405(a)(1)(1) 50.36(c)(1) ,,,,,, 50.73(a)(2)(v) _ 73.71(c)

PONER _

50.36(c)(2) 50.73(a)(2)(vil) Other (Specify LEVEL i 20.405(a)(1)(li) _ ,,,,, _

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20.405(a)(1)(lii) 50.73(a)(2)(1) 50.73(a)(2)(vill)(A) in Abstract (10) 0I 8I 9 ,,,_ _ _

,_,20.405(a)(1)(iv) 50.73(a)(2)(ll) 50.73(a)(2)(vill)(8) below and in

/,/ /,/,/,/,/,/,/,/,/,/,/,/,/,/ /,/,/,/,/,/,/,/,/,/ ,,,,, ,,,,,,

50.73(a)(2)(lii) 50.73(a)(2)(x) Text) f

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I LICENSEE CONTACT FOR THIS LER (12)

TELEPHONE NUpBER Name AREA CODE Michael Tennyson. Technical Staff Ennineer. entension 2704 81115 31 51 71 -l 61 71 61 1 werLETE ONE L!NE FOR EACH CurrussE FAILURE DESCRIBED IN TH15 REPORT (13)

CAUSE SYSTEM COMPONENT MANUFAC- REPORTABLE CAUSE SYSTEM COMPONENT MANUFAC- REPORTABLE TURER TO NPRDS TURTR TOWPRR,,,

1 I I I I I N I I i l I l l X Bl N 1 I I I I I I I I I l l l 1 Expected Month l Day l Year SUPPLEMENTAL REPORT EXPECTED (14)

Submission

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lyes (If ves. complete EXPECTED SugMISSION DATE) YlNO I l ABSTRACT (Limit to 1400 spaces, i.e. approximately fifteen single-space typewritten lines) (16) on May 15, 1989, at 2156 hours0.025 days <br />0.599 hours <br />0.00356 weeks <br />8.20358e-4 months <br />, the Reactor Core Isolation Cooling System (RCIC) received a Division I and Division 11 (outboard and inboard) isolation on NCIC high steam line flow. Unit I was in Operational Condition 1 (Run) at 89% power.

At the time of the event, RCIC steam line was being womed up following the conpletion of L15-RI-301, " Unit 1 Steam Line High Flow RCIC ! solation Functional Test." RCIC was being returned to standby per procedure, LOP-RI-05, Preparation for Standby of the RCIC system," when the outboard isolation valve (IE51.F008), and inboard isolation valves (IE51-F0b and IE51-F063) Isolated due to a spurious high steam flow signal.

The RCIC steam line isolation was not a valid high steam flow signal. Steam trapped between the inboard valves and the outboard valve was released into the piping downstream of the outboard valve when it was opened. The surge from this release was sufficient to exceed the trip setpoint of the high flow isolation switches.

When the isolation signal was received, the outboard isolation valve closed satisfactorily, RCIC system piping integrity was verified and the isolation logic was reset. Wanning up of the RCic system proceeded with no further incidents.

This event is reportable to the Nuclear Regulatory Comnission as a Licensee Event Report in accordance with 10CFR$0.73(a)(2)(iv) due to an Engineered Safety Feature actuation.

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' L78mt8F WJ;T REPORT (LER) TEXT OWiltalAT13 Fem Rev 2.0

  • L LER in=R (6) Pane (3)

FACILITY Igut (1) DOCKET IRNGER (2)

Year /// 5equential f/j/j/ Revision fff

/// louder /// Ilumber oI1le o! 1 of 2 0F 01 6 l wgnecanniv$tationunit1 o l's I o I o I o 1 31 71 3 e19 - -

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t TEXT- Energy Industry identification System (E!!5) codes are identified in the test as (IK)

. PLANT AllD ST5 TEM IDENTIFICATION General Electric - telling Water Reactor

! Energy Industry identification System (Ell 5) codes are identified in the text as (KX). ,

A. CONDITION PRIOR 70 EVENT.

Event Date: 5/15/09 Event ilme: 2156 Hours

~ Unit (s): 1 t

Mode (s) Name: Run Power Level (s): 895 Reactor Mode (s): 1 l S. DESCRIPTION OF EVENT

. On May 15,1989, at 2156 hours0.025 days <br />0.599 hours <br />0.00356 weeks <br />8.20358e-4 months <br /> the Reactor Core Isolation' Cooling System (RCIC, ON) received a Division I

I. I and Division 11 (inboard and outboard) isolation signal on RCIC high steam line flow. This event occurred while Unit 1 was in operational condition 1 (Run) at 895 power.

l At the time of the event, RCic stem line was being wamed up following the completion of LaSalle f' Instro ent Surveillance, L15-RI-301, " Unit 1 Steam Line Flow RCIC isolation Functional Test." During i this surveillance, the outboard RCIC steam isolation valve (1E51-F008) and the inboard steam isolation vaires (IE51-F063 and IE51-F076) were closed. Upon coupletion of the survelliance, RCIC was being returned to standby per LaSalle operating Procedure, LOP-RI-05, " Preparation for Standby of RCIC System."' The Control Room operator attempted several times to crack open the outboard isolation valve (1E51-F000), with the inboard valves closed.

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Shortly after the outboard valve apparently lifted off of its seat, the Operator noticed a step increase

. In RCIC stem line pressure downstream of the outboard isolation valve and lamediately closed the

. outboard valve. Within 3 seconds of the pressure increase the Olvision 1 outboard RCIC stem isolation valve (1E51-F006), and the olvision 11 inboard RCic stem isolation valves (IE51-F076 and IE51-F063) received an isolation signal due to a high stem flow signal from the pressure differential switches IE3141013AA and IE31-410130A.

l The inboard isolation valves were closed at the time of the isolation signal, and the outboard Isolation 1- valve had already closed due to the Operator's response. Subsequent to the isolation, the outboard

. valve was re-opened and the RCic steam line was wanned in accordance with the same procedure, this ' time l  ;

without incident.

L The relays that isolate the inboard and outboard isolation valves for the RCIC ste m line are time delayed to energire. The isolation time for each relay was checked and it was detennined that they functioned satisfactorily.

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LICENSEE EVENT REPORT (LER) TEXT *;0NTIWuATION _ _

Forn Rev 2.0 LER BRptER (6) Pace (3)

FACILITY MUE (1) DOCKET NuPSER (2)

Year // Sequential // Revision ,

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// thatner

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ol1Ie oI ) of 3 0F ol_1 l i  % 11e County station unit 1 oI5ioIoIo 1 31 71 3 sI9 - -

Energy Inoustry identification System (Ells) codes are identified in the text as (KK) l TEXT 1

g. OESCRIPTION OF EVENT (Continued) l The water which acc oulated in the RCIC steam Ilne piping between the inboard and outboard isolation
  • valves during the surveillance appears to affect the differential pressure instroents when it is pushed The flow elbow cannot accurately measure flow in ,

past one tap of the flow elbow by the trapped steam.

these circ ostances due to the difference of fluid density between the taps. ,

C. APPARENT CAUSE OF EVENT  !

The cause of the RCIC steam line isolation was a spurious high stem flow signal generated when steam j was admitted to the RCIC steam line. Apparently steam was trapped downstream of the inboorti isolation valves (1E51 F076 and 1E51-F063) and upstream of the outboard isolation vatte (1E51-F008). -l Upon re-opening of the outboard isolation valve, the trapped steam expanded into the downstream piping The isolation logic for high kCIC causing a surge of the steamfwater mixture and isolated the system.

steam line flow has a three second time delay built in it to prevent spurious isolation when fast l

. starting RCIC. Howev*r, the basis for the flow measurements used in the isolation logic is that the elbows would sense steam, not a steam / water mixture. The isolation was reset satisfactorily after it occurred.

O. SAFETY ANALYSIS OF EVENT

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Upon receiving the high steam Inne flow isolation signal, the RCIC steam line inboard and outboard  !

isolation valves isolated satisfactorily. This action was conservative from the standpoint of Primary Contaimment(PC)(NH] integrity.

All the valves were already closed. (IE51-F008 was closed due to Operator action prior to the automatic closure signal.) Therefore the isolation function of these valves had been met.

' Since the valves were already closed, the isolation signal did not cause any challenges to the valves or motor operators. RCIC was already inoperable due to surveillance testing. Satisfactory operation of the high flow differential pressure switches was observed during subsequent testing which showed that the pressure pulse (s) did not damage the switch diaphragras. -

Consequences of this event were minimal since the High Pressure Core Spray (HP) (BG) and other emergexy core coeling systems were fully operable.

E. CORRECTIVE ACTIONS RCIC system piping integrity was verifled and the isolation logic was reset. Warning up of the RCIC systam proceeded with no further incidents, and RCIC was returned to standby per procedure LOP-RI-05, "Proparation for Standby of the RCIC System," at 2245 hours0.026 days <br />0.624 hours <br />0.00371 weeks <br />8.542225e-4 months <br /> on May 15, 1989.

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LICEMEE EVENT REPORT (LER) TEXT CONTINuATimi Fore Rev 2.0 FACILITY NRpE (1) DOCKET NupSER (2) LER tRDSER (6) P ee (3)

Year /

fj/j/ Sequential ff//j/ Revision

/// Weber /// Neber o I 5 I o I o I o i 31 113 e19 - ol1Ie - oi1 01 4 0F of s l Lasalle County Station unit 1

. TEXT Energy industry identification System (E!!S) codes are identified in the text as (xx]

E.- CORRECTIVE ACTIONS (Continued)

LaSalle special Test, LST-89-019 was written to slaulate the act ul conditions for a RCIC isolation during warm up. The test was perfomed to detemine a course of action to prevent the occurrence of similar isolations. Actuation of one isolation switch was observed, but it was not of sufficient duration to energize the 3 second time delay required for isolation.

Several courses of action for prevention of RCic isolation were discussed at a meeting held on May 24, 1999. The following actions were agreed to be laplemented:

1. During the next required isolation for maintenance of the PCIC high stem flow instruments, a special test would be perfomed in conjunction with the instraent survel11ance. The pressure differential switches IE31-m013AA/Aa/DA/te, the time delay relays associated with these switches, and the RCic steam header pressure indicator 1E51-N001 downstro m of outboard isolation valve 1E51-F000, would all be monitored during system isolation, upon closure of inboard isolation valve IE51-F063, outboard isolation valve IE51-F008 would be closed after the RCIC steam Inne isolation valve 1E51-N007 reached 400 psig. At the completion of the RCic instrument maintenance, monitoring of the instroents would continue until RCIC was returned to standby.
2. LaSalle Onsite Review (LD5R)09-434 would be written to place the pressure differential switches IE31-N007AS/st and IE31-#013AB/88 out of service untti they are permanently removed by modification M01-1-40-052. These switches are piped "in reverse" and cannot sense a legitimate high steam flow condition.
3. LaSalle Operating procedures and LaSalle Instraent Survelliances would be revised as appropriate, following the evaluation of all Special Tests.

LaSalle Special Test, LST 99-059,

  • Pressure / Differential Pressure Observation of RCIC Ste m Line Hi-Flow l= Isolation Switches 1(2)E31-4013AA and 1(2)E31-N0138A,* was perfomed on June 9,1989. Due to the indeterminate results during the test, a new test LaSalle Special Test 89-062 was written and perfomed the following day.

During the RCIC system return to standby, there was no RCIC isolation. The test equipment remained connected and was monitored for three weeks to determine the possible drift that would occur to the pressure differential switches while RCIC was in service. it was determined that the drift in the switches was not sufficient to contribute to a RCIC system isolation during return to a standby condition.

LaSalle Special Test, LST 99-062 was performed a second time on July 11, 1999 inconjunctionwithaRCIC instrument surveillance. Following the closure of inboard isolation valve (IE51-F063), the RCIC steam Ilne pressure was reduced to 400 psig before the outboard isolation valve IE51-F008 was closed. Upon l-l RCIC return to service there was no RCIC isolation.

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  • Foria Rev 2.0 LICENSEE EVENT REMIRT (LER) TEXT CONiluuhTION 00CEtt NupSER (2) LER 8eptER (6) Pm Cl)

PACILITY NRpE (1)

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% )1e County Statten unit 1 015 10 1010131113 e19 - 011Ie - 01 1 01 5 0F 016 TIXT Energy Industry Identification System (Ell 5) codes are identified in the test as (KK) f E. CORRECTIVE ACTIONS (Continued)

After evaluation of the tests, it was decided that LA5alle Operating Procedure. LOP-RI-43

  • Shutdown of the RCIC System," would be revised. The revision was1d instruct the Control Room Operators to reduce the steam line pressure downstream of inboar11 isolation valve IE51-F063 to 400 psig before closing outboard isolation valve 1E51-F008. The pressure reduction in the steaminne would be accomplished by waiting a period of 45 to 50 minutes after closure of the inboar11 isolation valve. The revision of LaSalle Operating Precedure LOP 41-03, was completed on October 10, 1989.

All LaSalle Instroent Survel11ances that require the isolation of the RCIC system will a150 be revised to reflect that system isolation would be perforned in accordance with the specific operating precedure that is discussed in the above paragraph.

The following LaSalle Instrument Surveillances will be revised:

L1541-101, "Unnt 1 Steam Line High Flow RCIC lsolation Calibration.'

L1541-201, " Unit 2 Steam Line High Flow RCIC inciation Calibration.'

L15-RI-301, " Unit 1 Steam Line High Flow RCIC lsolation Functional fest."

L1541-401, " Unit 2 Steam Line High flow RCIC 1501stion f unctional Test.'

The change states that the RCIC system will be isolated in accordance with the revised LaSalle Operating Procedure, LDP-RI-03.

LaSalle Onsite Review, LOSR 99-034 was written on June 5, 1999 and approval to remove the switches from i

service was given on August 4, 1999.

On August 11, 1989, following a second RCIC system high steam flow isolation, a meeting was held and it was decided that the following additional corrective action would also be laplemented:

A revision to the LaSalle Electrical Surveillancee for setting the RCIC high flow isolatloa time delay relay. The setpoint for the time delay relays would be increased to 4 seconds from 3 seconds. The Technical Specification setpoint ilmit is 5 seconds.

LaSalle Setpoint Change Request SPCR 99-039/09-040 was initiated on August 31, 1989. LaSalle Electrical Surveillance LES-RI-1018 has been revised to reflect the 4 second setpoint change. The setpoint for the time delay relays on Unit 1 RCic system was changed on Septenber 28, 1999, during the refuel outage.

The setpoint change for Unit 2 RCIC system will be perforned during the next refuel outage.

The following LaSalle operating procedures and survelliance will be revised to reflect the 4 second change:

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PACILITY NepE (l) DOCKET NupeER (2) AP__:: (6) Sequential Revision i Year ///

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011ie 01 1 01 6 Or 01 6 t I m ile County statlan unit 1 0 i $ 1 0 1 0 1 0 1 31 71 3 sIe - -

Energy industry identification System (Ell 5) codes are identified in the text as (KK) l TEXT l

i E. C(MRECTIVE ACTIONS (Continued) ,

LOP-RI42, " Starting and Operation of the RCic System." i LOP 4144,

LOP 4145, " Preparation for the Standby of the RCic System.' '

LOS4143, *RCIC Sysiten Pep Operability Test.'

The fc110 wing LaSalle Operating Abnormals w'.11 be revised to reflect the 4 second change r

LOA 1(2)H13-P6010201, *RCIC Channel A Stem Line Olfferential Pressure High."

LOA 1(2)H13-P6018309, *RCic Channel S Stem Line Olfferential Pressure High."

The fo)1owing LaSalle schematic drawings will be revised to reflect the 4 second change:

IE-1-4226AD/AF ll-2-4226AD/AF p l

The pressure differentla) switches 2E314007AS/88 and 2E314013AS/es were taken out of service November l

3, 1989. The switches for the Unit 1 RCic system will be taken out of service during the startup sequence fc11owing the refuel outage.

All LaSalle Operating procedures Operating survel11ances, instroent surveillances, Operating

  • Abnormal Electrical survel11ances and schematic drawings will be tracked by Action item Record i

(AIR) 373-200-8947202.

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F. PREVIOUS EVENTS l

LER Number Title 373/85-022-00 RCIC Stem Line High Flow Isolation During Warsup "

373/84 460-00 RCIC Ste m Line Olfferential Pressure High 1so14 tion 373/83-122/03L Reit Stem Line Isolation During Warmup G.. COMPONENT FAlLURE DATA None.

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