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| issue date = 04/11/1994
| issue date = 04/11/1994
| title = LER 94-003-00:on 940318,ARPI Indicated Greater than Twelve Steps Deviation from Associated Group Counter.Caused by Rod Position Indication Varying W/Temp.Apris Adjusted.W/ 940411 Ltr
| title = LER 94-003-00:on 940318,ARPI Indicated Greater than Twelve Steps Deviation from Associated Group Counter.Caused by Rod Position Indication Varying W/Temp.Apris Adjusted.W/ 940411 Ltr
| author name = MOWREY C L, PLUNKETT T F
| author name = Mowrey C, Plunkett T
| author affiliation = FLORIDA POWER & LIGHT CO.
| author affiliation = FLORIDA POWER & LIGHT CO.
| addressee name =  
| addressee name =  
Line 16: Line 16:


=Text=
=Text=
{{#Wiki_filter:ACCELERATED DISTRIBUTION DEMONSTRATION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)ACCESSION NBR:9404190005 DOC.DATE: 94/04/11 NOTARIZED:
{{#Wiki_filter:ACCELERATED DISTRIBUTION DEMONSTRATION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)
NO DOCKET FACIL:50-251 Turkey Point Plant, Unit 4, Florida Power and Light C 05000251 AUTH.NAME AUTHOR AFFILIATION MOWREY,C.L.
ACCESSION NBR:9404190005               DOC.DATE: 94/04/11   NOTARIZED: NO           DOCKET FACIL:50-251 Turkey Point Plant, Unit 4, Florida Power and                 Light   C 05000251 AUTH. NAME           AUTHOR AFFILIATION MOWREY,C.L.         Florida     Power   & Light Co.
Florida Power&Light Co.PLUNKETT,T.F.
PLUNKETT,T.F.       Florida     Power   & Light Co.
Florida Power&Light Co.RECIP.NAME RECIPIENT'FFILIATION
RECIP.NAME           RECIPIENT'FFILIATION


==SUBJECT:==
==SUBJECT:==
LER 94-003-00:on 940318,ARPI indicated greater than twelve steps deviation from its associated group counter.Cause was rod position indication varies w/temperature.
LER   94-003-00:on 940318,ARPI indicated greater than twelve steps deviation from its associated group counter. Cause was                       D rod position indication varies w/temperature. Corrective action:ARPIs were adjusted.W/940411 ltr.
Corrective action:ARPIs were adjusted.W/940411 ltr.DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR ENCL SIZE: TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.NOTES D RECIPIENT ID CODE/NAME PD2-2 PD INTERNAL: AEOD/DOA AEOD/ROAB/DSP NRR/DE/EMEB NRR/DRCH/HHFB NRR/DRCH/HOLB NRR/DRSS/PRPB NRR/DSSA/SRXB RES/DSIR/EIB EXTERNAL EG&G BRYCE i J~H NRC PDR NSIC POORE,W.COPIES'ECIPIENT LTTR ENCL ID CODE/NAME 1 1 CROTEAUiR AEOD/DSP/TPAB NRR/DE/EELB NRR/DORS/OEAB NRR/DRCH/HICB NRR/DRIL/RPEB 2 RH~SSA/SPLB 1 RES FI.N 02 1 GNM~Ol 2 2 L ST LOBBY WARD'1 NSIC MURPHY i G A 1 1 NUDOCS FULL TXT COPIES LTTR ENCL 1 1 1 1 1 1'1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 D D D NOTE'TO ALL"RIDS" RECIPIENTS:
DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR                   ENCL     SIZE:
D D PLEASE HELP US TO'REDUCE WASTE!CONTACT THE DOCUMENT CONTROL DESK, ROOM P 1-37 (EXT.20079)TO ELIMINATE YOUR NAME FROM DISTIuBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 27 ENCL 27
TITLE: 50.73/50.9 Licensee Event Report (LER),               Incident Rpt, etc.
!l I, APR 11 leqrr L-94-075 10 CFR 50'3 U.ST Nuclear Regulatory Commission Attn: Document Control Desk Washingtonr D C 20555 Gentlemen:
NOTES RECIPIENT              COPIES'ECIPIENT                      COPIES            D ID  CODE/NAME            LTTR ENCL      ID CODE/NAME       LTTR ENCL D
Re: Turkey Point Unit 4 Docket No.50-251 Reportable Event: 94-003-00 Four Aanlog Rod Position Indicators Greater Than Twelve Steps From Group Step Counter;Technical Specification The attached Licensee Event Report 251/94-003-00 is being provided in accordance with 10 CFR 50.73, (a)(2)(i)(B).If there are any questions, please contact us.Very truly yours, g+T.F.Plunkett Vice President Turkey Point Plant TFP/CLM/cm enclosure copies: S.D.Ebneter, Regional Administrator, Region II, USNRC T.P.Johnson, Senior Resident Inspector, USNRC, Turkey Point Q~8 re@vvv (V 9404190005 940411 ,PDR ADOCK 05000251 8 PDR an FPL Group companY 0 4 ,I LICENSEE EVENT REPORT (LER)FACILITY NAME (1)TITLE (4)TURKEY POINT UNIT 4 DOCKET NUMBER (2)05000251 PAGE (3)QF 3 FOUR ANALOG ROD POSITION INDICATORS GREATER THAN TWELVE STEPS DEVIATION FROM GROUP STEP COUNTERS;ENTRY INTO TECHNICAL SPECIFICATION 3.0.3 evENT DATe (s)LER NUMBER(6)RPT DATE (7)OTHER FACILITIES INV, (8)MON DAY YR 03 18 94 OPERATING MODE (9)YR SEQ 4 R)003 00 MON DAY YR 04 XX 94 FACII ITY NAMES DOCKET 4<S)PONER LEVEL (10)88%10 CFR 50.73 a 2 i B LICENSEE CONTACT FOR THIS LER (12)C.L.Mowrey, Licensing OEF Engineer/Analyst TELEPHONE NUMBER 305-246-6204 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)CAUSE SYSTEM IU COMPONENT MANUFACTURER W120 NPRDS2 NO CAUSE SYSTEM COMPONENT MANUFACTURER DAY NPRDS2 YEAR'UPPLEMENTAI tREPORT EXPECTED<14)NO 0 YES 0 (If Yes, coeylete EXPECTED SUBMISSION DATE)EXPECTED SUBMISSION DATE (15)MONTH ABSTRACT (16)On March 18, 1994, with Unit 4 at about 8896 rated power, Analog Rod Position Indication (ARPI)for first one, rod, then three more rods, all in Bank D, indicated more than twelve steps deviation from their associated group step counters.Incore flux maps verified that all Bank D rods were at 190 steps.ARPIs were adjusted to read 190 steps.The rod position indication varies with temperature, and the phenomenon has been known since 1972.The vendor has stated that the variation is inherent to the design of-the system, and Technical Specifications allow a one-hour soak time after rod motion, during which most of the apparent misalignments correct themselves.
PD2-2 PD                     1    1    CROTEAUiR              1    1 INTERNAL: AEOD/DOA                                   AEOD/DSP/TPAB          1    1 NRR/DE/EELB            1    1' AEOD/ROAB/DSP NRR/DE/EMEB                               NRR/DORS/OEAB                1 NRR/DRCH/HHFB                             NRR/DRCH/HICB          1    1 NRR/DRCH/HOLB                            NRR/DRIL/RPEB          1    1 NRR/DRSS/PRPB                       2      RH~SSA/SPLB            1    1 NRR/DSSA/SRXB                       1    RES  FI.N      02      1    1 RES/DSIR/EIB                       1      GNM~          Ol      1    1 EXTERNAL   EG&G BRYCE i J ~ H           2    2    L ST LOBBY  WARD'      1    1 NRC PDR                             1    NSIC MURPHY i G A      1    1 NSIC POORE,W.                 1    1    NUDOCS FULL TXT        1   1 D
Since there is no Technical Specification action statement for more than one inoperable ARPI in a bank, Unit 4 entered Technical Specification 3.0.3.A task team investigating an earlier similar event (LER 251-92-001), confirmed the cause, and identified and corrected several contributing conditions.
D D
The team was not able to arrive at a cost-effective modification to completely eliminate the problem, but investigation for other contributing conditions continues.
NOTE'TO ALL "RIDS" RECIPIENTS:
The ARPIs for the four rods were adjusted to read 190 steps, and Technical Specification 3'.3 was exited.
PLEASE HELP US TO'REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM P 1-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTIuBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!
IO LICENSEETENT REPORT (LER)TEXT QHTINUATION FACILITY NAME TURKEY POINT UNIT 4 DOCKET NUMBER LER NUMBER PAGE NO.05000251 94-003-00 02 OF 03 X.DESCRXPTXON OF THE EVENT On March 18, 1994, Turkey Point Unit 4 was raising power toward 100%, following a maintenance outage.At about 1505, with power at approximately 88%and Bank D group step counters indicating 190 steps, Analog Rod Position Indication (ARPI)[EIIS:IU]for Rod D-8 indicated greater than twelve steps deviation from its associated group step counter.Technical Specification 3.1~3.1 Action Statement was entered, requiring verification of the rod location by flux map.Reactor Engineering was notified and at about 1600 completed flux maps which verified that all Bank D rods were at 190 steps.Maintenance personnel were called to adjust ARPI for Rod D-8 to read 190 steps.Before the adjustment was made, at about 1615, ARPIs for rods M-8, H-4, and H-12, all in, Bank'D, also drifted to greater than.twelve steps deviation from their associated group step counters (still at 190 steps).Because all Bank D rods had just been verified to be at 190 steps, ARPIs for all four rods were declared inoperable.
FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR               27  ENCL   27
Since there is no Technical Specification action statement for more than one inoperable ARPI in a bank, Unit 4 entered Technical Specification 3.0.3.By 1625, all four ARPIs had been adjusted to 190 steps, and Unit 4 exited Technical Specification 3.0.3.The NRCOC was notified at 1700.XX.CAUSE OF THE EVENT The root cause of this event is that rod position indication varies with temperature.
 
This temperature variation was first observed at Turkey Point in 1972.Westinghouse stated that temperature variations in indications are inherent to the design of the system.A special test was conducted at Turkey Point in 1975 to investigate this phenomenon, but the results were inconclusive.
  !l I,
Generally the temperature dependent variation is corrected within the one hour thermal soak time allowed by Technical Specification 3.1.3.2.A Turkey Point task team investigated a similar event, reported in LER 251-92-001, and verified that the temperature variation is indeed inherent to the design of the system.While no cost-effective modification has been identified to completely eliminate the problem, the investigations continue at Turkey Point and at another facility with the same design.Two contributing factors identified by the task team (contaminated connectors, and coil polarity)have been corrected.
 
Additionally, procedures have been developed to aid in diagnosing and correcting ARPI troubles.III.ANALYSIS OF THE EVENT The operability of the ARPIs is required to determine control rod positions and thereby ensure compliance with the control rod alignment and insertion limits.The requirements of Technical Specification 3.1.3.2 are intended to ensure that the potential effects of rod misalignment are bounded by the accident analyses.Incore flux maps determined that all rods were aligned properly, and the ARPIs were adjusted to indicate the correct rod positions.
APR 11 leqrr L-94-075 10 CFR 50 '3 U. ST  Nuclear Regulatory Commission Attn: Document Control Desk Washingtonr      D C  20555 Gentlemen:
Since all rods were physically aligned at all times, the health and safety of the public were not affected.
Re:      Turkey Point Unit  4 Docket No. 50-251 Reportable Event: 94-003-00 Four Aanlog Rod Position Indicators Greater Than Twelve Steps From Group Step Counter; Technical Specification The      attached Licensee Event Report 251/94-003-00    is being provided in accordance with 10 CFR 50.73, (a) (2) (i)  (B) .
0 0 I ICENSEEITENT REPORT (LER)TEXT eNTINCATION FACILITY NAME)TURKEY POINT UNIT 4 DOCKET NUMBER 05000251 LER NUMBER PAGE NO.94-003-00 03 OF 03 ZV.CORRECTIVE ACTZONS 2.Incore Flux maps were performed and determined the rods to be aligned properly,.
If there are any questions, please contact us.
In accordance with procedures 4-PMI-028.3 and'MI-028.30, the ARPIs were adjusted to indicate properly.V.ADD ZT ZONAL INFORMATION EIIS Codes are shown in the format[EIIS SYSTEM: IEEE component function identifier, second component function identifier (if appropriate)].
Very      truly  yours, g+Plunkett T. F.
A similar event occurred in February, 1992, and was reported in LER 251-92-001.
Vice President Turkey Point Plant TFP/CLM/cm enclosure copies:
il'0}}
S. D. Ebneter, Regional Administrator, Region II, USNRC T. P. Johnson, Senior Resident Inspector, USNRC, Turkey Point Q~ 8 re@
vvv    (V 9404190005 940411
,PDR    ADOCK 05000251 8                    PDR an FPL Group companY
 
0 4
    ,I
 
LICENSEE EVENT REPORT                                                        (LER)
DOCKET NUMBER  (2)        PAGE (3)
FACILITY NAME (1)
TURKEY POINT UNIT 4                                                   05000251                        QF      3 TITLE (4)
FOUR ANALOG ROD POSITION INDICATORS GREATER THAN TWELVE STEPS                                                 DEVIATION FROM GROUP STEP COUNTERS; ENTRY INTO TECHNICAL SPECIFICATION                                               3.0.3 evENT DATe (s)           LER NUMBER(6)           RPT DATE (7)             OTHER FACILITIES INV, (8)
YR           YR     SEQ       R)     MON     DAY   YR                                                         DOCKET 4 <S)
MON      DAY                              4                                                    FACII ITY  NAMES 03        18      94                  003      00    04      XX    94 OPERATING MODE (9)
PONER LEVEL  (10)       88%
10 CFR     50.73     a     2     i   B LICENSEE CONTACT FOR THIS LER (12)
TELEPHONE NUMBER C. L. Mowrey,           Licensing       OEF   Engineer/Analyst                                                       305-246-6204 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT   (13)
CAUSE   SYSTEM         COMPONENT     MANUFACTURER             NPRDS2     CAUSE       SYSTEM                       MANUFACTURER       NPRDS2 COMPONENT IU                              W120                NO
'UPPLEMENTAI tREPORT EXPECTED <14)     NO   0         YES 0                                     EXPECTED SUBMISSION MONTH        DAY        YEAR DATE (15)
(If Yes, coeylete EXPECTED SUBMISSION DATE)
ABSTRACT (16)
On   March 18, 1994, with Unit 4 at about 8896 rated power, Analog Rod Position Indication (ARPI) for first one, rod, then three more rods, all in Bank D, indicated more than twelve steps deviation from their associated group step counters. Incore flux maps verified that all Bank D rods were at 190 steps.
ARPIs were adjusted to read 190 steps.                             The rod position indication varies with temperature, and the phenomenon has been known since 1972. The vendor has stated that the variation is inherent to the design of -the system, and Technical Specifications allow a one-hour soak time after rod motion, during which most of the apparent misalignments correct themselves.                                                 Since there is no Technical Specification action statement for more than one inoperable ARPI in a bank, Unit 4 entered Technical Specification 3.0.3.
A task team investigating an earlier similar event (LER 251-92-001),
confirmed the cause, and identified and corrected several contributing conditions. The team was not able to arrive at a cost-effective modification to completely eliminate the problem, but investigation for other contributing conditions continues.
The ARPIs for the four rods were adjusted to read 190 steps, and Technical Specification 3 '.3 was exited.
 
IO LICENSEETENT         REPORT   (LER) TEXT QHTINUATION FACILITY NAME                 DOCKET NUMBER     LER NUMBER         PAGE NO.
TURKEY POINT UNIT 4                05000251          94-003-00           02 OF 03 X. DESCRXPTXON OF THE EVENT On March 18, 1994, Turkey Point Unit 4 was raising power toward 100%,
following a maintenance outage. At about 1505, with power at approximately 88% and Bank D group step counters indicating 190 steps, Analog Rod Position Indication (ARPI) [EIIS:IU] for Rod D-8 indicated greater than twelve steps deviation from its associated group step counter. Technical Specification 3.1 3.1 Action Statement was entered, requiring verification of the rod
    ~
location by flux map. Reactor Engineering was notified and at about 1600 completed flux maps which verified that all Bank D rods were at 190 steps.
Maintenance personnel were called to adjust ARPI for Rod D-8 to read 190 steps.
Before the adjustment was made, at about 1615, ARPIs for rods M-8, H-4, and H-12, all in, Bank 'D, also drifted to greater than .twelve steps deviation from their associated group step counters (still at 190 steps).               Because all Bank D rods had just     been verified   to be at 190 steps,   ARPIs for all four rods were declared inoperable.         Since there is no Technical Specification action statement for more than one inoperable ARPI in a bank, Unit 4 entered Technical Specification 3.0.3. By 1625, all four ARPIs had been adjusted to 190 steps, and Unit 4 exited Technical Specification 3.0.3.               The NRCOC was notified at   1700.
XX. CAUSE OF THE EVENT The   root cause of this event is that rod position indication varies with temperature. This temperature variation was first observed at Turkey Point in 1972. Westinghouse stated that temperature variations in indications are inherent to the design of the system. A special test was conducted at Turkey Point in 1975 to investigate this phenomenon, but the results were inconclusive. Generally the temperature dependent variation is corrected within the one hour thermal soak time allowed by Technical Specification 3.1.3.2.
A Turkey Point task team investigated a similar event, reported in LER 251-92-001, and verified that the temperature variation is indeed inherent to the design of the system. While no cost-effective modification has been identified to completely eliminate the problem, the investigations continue at Turkey Point and at another facility with the same design. Two contributing factors identified by the task team (contaminated connectors, and coil polarity) have been corrected. Additionally, procedures have been developed to aid in diagnosing and correcting ARPI troubles.
III. ANALYSIS OF     THE EVENT The   operability of the ARPIs is required to determine control rod positions and thereby ensure compliance with the control rod alignment and insertion limits. The requirements of Technical Specification 3.1.3.2               are intended to ensure that the potential effects of rod misalignment are bounded by the accident analyses.     Incore flux maps determined that         all rods were aligned properly,   and the ARPIs were adjusted   to indicate   the correct   rod positions.
Since   all rods were physically aligned at       all times, the health and safety of the public   were not   affected.
 
0 0
 
I ICENSEEITENT   REPORT   (LER) TEXT eNTINCATION FACILITY NAME             DOCKET NUMBER     LER NUMBER         PAGE NO.
) TURKEY POINT UNIT 4              05000251          94-003-00          03 OF 03 ZV. CORRECTIVE ACTZONS Incore Flux maps were performed and determined the rods to be aligned properly,.
: 2. In accordance with procedures 4-PMI-028.3 and 'MI-028.30, the ARPIs were adjusted to indicate properly.
V. ADDZT ZONAL INFORMATION EIIS Codes are shown in the format [EIIS     SYSTEM: IEEE component function identifier, second component   function identifier   (if appropriate)].
A similar event occurred in February, 1992, and was reported in LER 251-92-001.}}

Latest revision as of 08:36, 22 October 2019

LER 94-003-00:on 940318,ARPI Indicated Greater than Twelve Steps Deviation from Associated Group Counter.Caused by Rod Position Indication Varying W/Temp.Apris Adjusted.W/ 940411 Ltr
ML17352A532
Person / Time
Site: Turkey Point NextEra Energy icon.png
Issue date: 04/11/1994
From: Mowrey C, Plunkett T
FLORIDA POWER & LIGHT CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
L-94-075, L-94-75, LER-94-003, LER-94-3, NUDOCS 9404190005
Download: ML17352A532 (10)
v • d • e


Text

ACCELERATED DISTRIBUTION DEMONSTRATION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9404190005 DOC.DATE: 94/04/11 NOTARIZED: NO DOCKET FACIL:50-251 Turkey Point Plant, Unit 4, Florida Power and Light C 05000251 AUTH. NAME AUTHOR AFFILIATION MOWREY,C.L. Florida Power & Light Co.

PLUNKETT,T.F. Florida Power & Light Co.

RECIP.NAME RECIPIENT'FFILIATION

SUBJECT:

LER 94-003-00:on 940318,ARPI indicated greater than twelve steps deviation from its associated group counter. Cause was D rod position indication varies w/temperature. Corrective action:ARPIs were adjusted.W/940411 ltr.

DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR ENCL SIZE:

TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

NOTES RECIPIENT COPIES'ECIPIENT COPIES D ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL D

PD2-2 PD 1 1 CROTEAUiR 1 1 INTERNAL: AEOD/DOA AEOD/DSP/TPAB 1 1 NRR/DE/EELB 1 1' AEOD/ROAB/DSP NRR/DE/EMEB NRR/DORS/OEAB 1 NRR/DRCH/HHFB NRR/DRCH/HICB 1 1 NRR/DRCH/HOLB NRR/DRIL/RPEB 1 1 NRR/DRSS/PRPB 2 RH~SSA/SPLB 1 1 NRR/DSSA/SRXB 1 RES FI.N 02 1 1 RES/DSIR/EIB 1 GNM~ Ol 1 1 EXTERNAL EG&G BRYCE i J ~ H 2 2 L ST LOBBY WARD' 1 1 NRC PDR 1 NSIC MURPHY i G A 1 1 NSIC POORE,W. 1 1 NUDOCS FULL TXT 1 1 D

D D

NOTE'TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO'REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM P 1-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTIuBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 27 ENCL 27

!l I,

APR 11 leqrr L-94-075 10 CFR 50 '3 U. ST Nuclear Regulatory Commission Attn: Document Control Desk Washingtonr D C 20555 Gentlemen:

Re: Turkey Point Unit 4 Docket No. 50-251 Reportable Event: 94-003-00 Four Aanlog Rod Position Indicators Greater Than Twelve Steps From Group Step Counter; Technical Specification The attached Licensee Event Report 251/94-003-00 is being provided in accordance with 10 CFR 50.73, (a) (2) (i) (B) .

If there are any questions, please contact us.

Very truly yours, g+Plunkett T. F.

Vice President Turkey Point Plant TFP/CLM/cm enclosure copies:

S. D. Ebneter, Regional Administrator, Region II, USNRC T. P. Johnson, Senior Resident Inspector, USNRC, Turkey Point Q~ 8 re@

vvv (V 9404190005 940411

,PDR ADOCK 05000251 8 PDR an FPL Group companY

0 4

,I

LICENSEE EVENT REPORT (LER)

DOCKET NUMBER (2) PAGE (3)

FACILITY NAME (1)

TURKEY POINT UNIT 4 05000251 QF 3 TITLE (4)

FOUR ANALOG ROD POSITION INDICATORS GREATER THAN TWELVE STEPS DEVIATION FROM GROUP STEP COUNTERS; ENTRY INTO TECHNICAL SPECIFICATION 3.0.3 evENT DATe (s) LER NUMBER(6) RPT DATE (7) OTHER FACILITIES INV, (8)

YR YR SEQ R) MON DAY YR DOCKET 4 <S)

MON DAY 4 FACII ITY NAMES 03 18 94 003 00 04 XX 94 OPERATING MODE (9)

PONER LEVEL (10) 88%

10 CFR 50.73 a 2 i B LICENSEE CONTACT FOR THIS LER (12)

TELEPHONE NUMBER C. L. Mowrey, Licensing OEF Engineer/Analyst 305-246-6204 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

CAUSE SYSTEM COMPONENT MANUFACTURER NPRDS2 CAUSE SYSTEM MANUFACTURER NPRDS2 COMPONENT IU W120 NO

'UPPLEMENTAI tREPORT EXPECTED <14) NO 0 YES 0 EXPECTED SUBMISSION MONTH DAY YEAR DATE (15)

(If Yes, coeylete EXPECTED SUBMISSION DATE)

ABSTRACT (16)

On March 18, 1994, with Unit 4 at about 8896 rated power, Analog Rod Position Indication (ARPI) for first one, rod, then three more rods, all in Bank D, indicated more than twelve steps deviation from their associated group step counters. Incore flux maps verified that all Bank D rods were at 190 steps.

ARPIs were adjusted to read 190 steps. The rod position indication varies with temperature, and the phenomenon has been known since 1972. The vendor has stated that the variation is inherent to the design of -the system, and Technical Specifications allow a one-hour soak time after rod motion, during which most of the apparent misalignments correct themselves. Since there is no Technical Specification action statement for more than one inoperable ARPI in a bank, Unit 4 entered Technical Specification 3.0.3.

A task team investigating an earlier similar event (LER 251-92-001),

confirmed the cause, and identified and corrected several contributing conditions. The team was not able to arrive at a cost-effective modification to completely eliminate the problem, but investigation for other contributing conditions continues.

The ARPIs for the four rods were adjusted to read 190 steps, and Technical Specification 3 '.3 was exited.

IO LICENSEETENT REPORT (LER) TEXT QHTINUATION FACILITY NAME DOCKET NUMBER LER NUMBER PAGE NO.

TURKEY POINT UNIT 4 05000251 94-003-00 02 OF 03 X. DESCRXPTXON OF THE EVENT On March 18, 1994, Turkey Point Unit 4 was raising power toward 100%,

following a maintenance outage. At about 1505, with power at approximately 88% and Bank D group step counters indicating 190 steps, Analog Rod Position Indication (ARPI) [EIIS:IU] for Rod D-8 indicated greater than twelve steps deviation from its associated group step counter. Technical Specification 3.1 3.1 Action Statement was entered, requiring verification of the rod

~

location by flux map. Reactor Engineering was notified and at about 1600 completed flux maps which verified that all Bank D rods were at 190 steps.

Maintenance personnel were called to adjust ARPI for Rod D-8 to read 190 steps.

Before the adjustment was made, at about 1615, ARPIs for rods M-8, H-4, and H-12, all in, Bank 'D, also drifted to greater than .twelve steps deviation from their associated group step counters (still at 190 steps). Because all Bank D rods had just been verified to be at 190 steps, ARPIs for all four rods were declared inoperable. Since there is no Technical Specification action statement for more than one inoperable ARPI in a bank, Unit 4 entered Technical Specification 3.0.3. By 1625, all four ARPIs had been adjusted to 190 steps, and Unit 4 exited Technical Specification 3.0.3. The NRCOC was notified at 1700.

XX. CAUSE OF THE EVENT The root cause of this event is that rod position indication varies with temperature. This temperature variation was first observed at Turkey Point in 1972. Westinghouse stated that temperature variations in indications are inherent to the design of the system. A special test was conducted at Turkey Point in 1975 to investigate this phenomenon, but the results were inconclusive. Generally the temperature dependent variation is corrected within the one hour thermal soak time allowed by Technical Specification 3.1.3.2.

A Turkey Point task team investigated a similar event, reported in LER 251-92-001, and verified that the temperature variation is indeed inherent to the design of the system. While no cost-effective modification has been identified to completely eliminate the problem, the investigations continue at Turkey Point and at another facility with the same design. Two contributing factors identified by the task team (contaminated connectors, and coil polarity) have been corrected. Additionally, procedures have been developed to aid in diagnosing and correcting ARPI troubles.

III. ANALYSIS OF THE EVENT The operability of the ARPIs is required to determine control rod positions and thereby ensure compliance with the control rod alignment and insertion limits. The requirements of Technical Specification 3.1.3.2 are intended to ensure that the potential effects of rod misalignment are bounded by the accident analyses. Incore flux maps determined that all rods were aligned properly, and the ARPIs were adjusted to indicate the correct rod positions.

Since all rods were physically aligned at all times, the health and safety of the public were not affected.

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I ICENSEEITENT REPORT (LER) TEXT eNTINCATION FACILITY NAME DOCKET NUMBER LER NUMBER PAGE NO.

) TURKEY POINT UNIT 4 05000251 94-003-00 03 OF 03 ZV. CORRECTIVE ACTZONS Incore Flux maps were performed and determined the rods to be aligned properly,.

2. In accordance with procedures 4-PMI-028.3 and 'MI-028.30, the ARPIs were adjusted to indicate properly.

V. ADDZT ZONAL INFORMATION EIIS Codes are shown in the format [EIIS SYSTEM: IEEE component function identifier, second component function identifier (if appropriate)].

A similar event occurred in February, 1992, and was reported in LER 251-92-001.

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