ML17306B114

LER 92-014-00:on 921008,discovered Operation in Excess of Licensed Condition for Thermal Power.Caused by Inaccurate Span Correction Factors.Operating Units Reduced Power to 99.5 Percent power.W/921106 Ltr

ML17306B114
Person / Time
Site:	Palo Verde
Issue date:	11/06/1992
From:	Bradish T, James M. Levine ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
192-00809-JML-T, 192-809-JML-T, LER-92-014, LER-92-14, NUDOCS 9211160282
Download: ML17306B114 (14)

Text

~CCZI.ZR~TZD SmISuTIOX DiiVrOmra~nOw svsrzvr REGULATORY INFORMATION DISTRIBUTIO&SYSTEM (RIDS)

'ACCESSION NBR:921'1160282 DOC.,DATE: 92/11/06 NOTARIZED: 'NO DOCKET FACIL:STN-50-528 Palo Verde Nuclear Station,'nit',. Arizona Publi 05000528 AUTH'MPd4E AUTHOR AFFILIATION BRADISH,T.R'. Arizona Public Service Co. (formerly Arizona Nuclear Power LEVINE,J.M. Arizona Public:Service Co. (formerly Arizona Nuclear Power RECIP.NAME =

RECIPIENT AFFILIATION SUBJECT,: LER 92-01'4-00:on 921008,di;scovered operation in excess. of licensed condition for thermal power. Caused by inaccurate span correction factors. Operating Units reduced power to 99.5 percent, power.,W/921106 ltr.

DISTRIBUTION CODE:, IE22T COPIES RECEIVED:LTR ENCL. .SIZE:

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

PLANT 05000528/ D'OTES:STANDARDIZED

'A PD5 LA RECIPIENT ID CODE/NAME TRAMMELLiC l,l COPIES LTTR ENCL 1 .1 PD5 RECIPIENT ID PD'CRS CODE/NAME COPIES LTTR ENCL 1 1' D D

INTERNAL: ACNW 2 2' 2 AEOD/DOA 1 AEOD/DSP/TPAB 1 1 AEOD/ROAB/DSP 2 2 7E

'RR/DET/EMEB 1 1 NRR/DLPQ/LHFB10 1

• NRR/DLPQ/LPEB10 '1 1

=1'1 NRR/DOEA/OEAB'RR/DST/SELB 1' NRR/DREP/PRPB11 2 2 8D 1 NRR/DST/SICB8H3 1 1 RR/KQT/ PLB8Dl 1 1 NRR/DST/SRXB 8E .1 1 REG FILE 02 1 1 RES/DSIR/EIB 1 '

RGN ILE 01 1 1' EXTERNAL 'EG&G BRYCEg J H 2 L ST LOBBY WARD l.'

NRC PDR ~

1 1 NSIC MURPHY,G.A 1 1 NSIC POOREgW 1 1 NUDOCS FULL TXT 1 1 D

NOTE TO ALL RIDS RECIPIENTS PLEASE HELP-US TO REDUCE WASTE! 'CONTACT THE DOCUMENT D CONTROL DESK.

ROOM Pl-37 (EXT. 504-2065) TO ELIMINATEYOUR NAME FROM'DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 31 ENCL 31

igt Arizona Public Service Company PALO VERDE NUCLEAR GENERATING STATION P.O. BOX 52034 ~ PHOENIX, ARIZONA 85072-2034 JAMES M. LEVINE VICE PRESIDENT 192-00809-JML/TRB/JJN NUCLEAR PRODUCTION November '6,. 1992 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Mail Station D.C.

Pl-37'ashington, 20555.

Subject:

Palo Verde Nuclear Generating Station (PVNGS)

Units 1, 2, and 3 Docket 'Nos. STN 50-528, 529, and 530 License No. NPF-41, 51, and 74 Licensee Event Report 92-014-00 File'2-020-4'04 Attached please find Licensee Event Report (LER) 92-014-00,prepared and submitted pursuant to 10CFR50.73. This LER'eports the probable violation of the operating license condition 2.C.1 for maximum thermal power level due to inaccurate span correction factors supplied by Rosemount Inc. for the static pressure effect on differential pressure transmitters. In accordance with 10CFR50.73(d) a 'copy of this LER is being forwarded to the Regional Admini'strator, 'NRC Region V.

If you have any questions,,please contact T. R. Bradish, Compliance Manager, at (602) 393-5421.

- Very truly yours, JML/TRB/JJN/mh Attachment cc: W. F. Conway (all with attachment)

J. B. Martin J. A. Sloan INPO Records Center 92111b0282 05000528, TI2110b PDR ,ADOCK S PDR

i+i LICENSEE EVENT REPORT (LER)

FACIUTYNAl% (I) DOCKET NUMBER (2) PACE Palo Verde Unit 1 0 5 0 0'0 52 B 1OFO 5 TITUi(4)

Operation in Excess of Licensed Condition for Thermal 'Power EV (4) R <4) EPORT ATE P) 0 F 8 0 ED(4)

YEAR FACIUIYNAMES DOCKET NUMBER(S),

e. DAY MONTH DAY YEAR NUMBER NUMBER MONTH Palo Verde Unit 2 osooo 1 008 2 9 2 0 14 0 0 THIS REPORT IS SUBMITTED PURSUANT TO THE REOVIREMENTS OF 10 CFR Palo Verde Unit 3 I: (Check one or mora ot tha MowIng) (11) osooo,50 MoDE (4) 20A02(b) 20AOS(c) 50.73(a)(2)<iv) 73.71(b) 1 20AOS(aXI g) 5096(c)(1) SIL73<aX2) ) 73.71(c) 20AOS(aXIXIB 5044(c)(2) 50 73<aX~)b6t). OTHER Ppact<y In Abrtrart balcw anrt tn TatA NRC Form 20AOS(aXI)gl) 50'73<a)(2Ã) so.73<a>g)B61>(A) 366A) 20AOS(aXI)gv) 50.73(a)(2)(ll) 50 73<aX2)<~XB) License 20AOS(a/1/v) 50.73(a) (2XIH) 50.73(a)(2)(x) Condition UCENSEE CONTACT FOR THIS LER (I 2)

NAME TELEPHONE NUMBER Thomas R. Bradish, Compliance Manager 602 393-5421 COMPUiTE ONE UNE FOR EACH COMPOIIENT FAILURE DESCRBED SI TIES REPORT (13)

CAUSE YSTEM COMPONENT MANUFAC TURER 'o EPORTABLE NPRDS .

COMPONENT MANUFAC.

TURER EPORTABL TO NPRDS SUPPtEMENTAL REPORT EXPECTED (16) DAY YEAR EXPECTED SVBNSSION DATE (15)

YES (tfyaa, contplata EXPECTED SUBMISQOII DATQ No AssTRAGT <Ltmtt to 1600 apacaa la, appccvrtmataty Shran atngta apnea typawrtttantnaa) (14)

On October 8, 1992, Palo Verde Units 1 and 2 were in Mode 1 (POWER OPERATION) and Unit 3 was shutdown for a refueling outage, when Engineering personnel concluded that license condition 2.C.l for the power level may have been periodically exceeded by as much as 0.2 percent in all- three Units. This condition was discovered as a result of an APS Engineering review of a 10CFR21 notification from Rosemount. The notification provided revised correction factors for the effect of static pressure on the measurement of differential pressure.

The cause of the thermal power exceeding the licensed condition limit: was inaccurate span correction factors provided by Rosemount, the manufacturer of the differential pressure transmitter. As a result, the calibration procedures insufficiently compensated for the effect of static pressure which in turn resulted in the actual feedwater flow rate being greater than the indicated value. The feedwater flow rate is used in the algorithm to calculate the secondary calorimetric.

As immediat:e corrective action, the operating Units reduced power to approximately 99.5 percent power. No similar events have been"previously reported pursuant to 10CFR50.73.

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION FACII.ITYNAME DOCKET NUMBER 'AOE YEAR SEOUENTIAl REVISION 5> NUMBER zc~<'UMBER Palo Verde Unit 1 osooo,528 9 2 014 0 002 OF 0 5 I. DESCRIPTION OF WHAT OCCURRED:

A. Initial Conditions:

On October 8, 1992, Palo Verde Units 1 and 2 were in Mode 1 (POWER OPERATION) at approximately 100 percent power and Unit 3 was shutdown with the core offloaded for a refueling outage.

Reportable Event Description (Including Dates and Approximate Times of Major Occurrences):

Event Classification: Violation License Condition 2.C.l, Maximum Power Level On October 8, 1992, APS Engineering personnel concluded that license condition 2.C.1 for the maximum power level (3800 megawatts thermal) may have been periodically exceeded by as much as 0.2 percent in all three Units. This condition was discovered as a result of an APS Engineering review of a 10CFR21 notification from Rosemount Inc. This notification provided revised correction factors for the effect of static pressure on the measurement of differential pressure. As a result of the original correction factors being used in the calibration procedures, the feedwater flow rate was nonconservatively indicated which in turn resulted'n a nonconservative calculation of thermal power.

Prior to the event, Rosemount Inc. discovered the inaccurate span correction factors during testing of model 1152 differential pressure transmitters (PDT). Using new and more accurate test equipment, Rosemount Inc. was able to more precisely measure the affect of static pr'essure on the measured differential pressure.

On August 31, 1992, Rosemount Inc. sent APS a 10CFR21 notification providing revised span correction factors for the static pressure effect on the indicated differential pressure for the model 1152 PDTs.

APS Engineering personnel reviewed the notification and evaluated the impact at Palo Verde. This review and evaluation determined that the feedwater flow transmitters (PDT)(SJ) would indicate less.

than the actual flow. Since feedwater flow is an input to the secondary calorimetric and the secondary calorimetric is used to calibrate the primary power, the actual thermal power may have exceeded the indicated thermal power by as much as 0.2 percent.

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LICENSEE EVENT REPORT (LER) TEXT CONTINUATION FACIUTYNAME 'OCKET NtNBER 'ACE REVIQON NVLI8ER Palo Verde Unit 1 o ,s. o o. o 5 2 8 9 2 0 1 4 0 0 0 OF 0;5 C. Status of structures, systems, or components that were'noperable at the start of the event that contributed to the event:

Not appli'cable - no structures, .systems, or components were .

inoperable at the start of, the event which contributed to'his event.

Cause of each component or sy'tem failure, if known:

r Not applicable - no component or system failures were involved.

Fa'ilure mode, mechanism, and effect of each 'failed component, if known:

Not applicable - no component failures were involved'..

,F. For failures of components with mul'tiple 'functions, list of systems or, secondary functions that wer'e,also affected:

Not applicable - no failures of components with multiple functions.

were involved.

For a failure that rendered a train. of a safety system inoperable, estimated time elapsed from the discovery of the failure until 'the train was returned to service:

Not applicable - no failures that rendered a train of a safety system inoperable were involved.

H. Method of discovery of each component or system failure or procedural error As a result of the Rosemount Inc. 10CFR21 notification, APS Engineering personnel were notified of the inaccurate span correction factor and identified that this data was used in the calibration procedure for the affected transmitters.

Cause of Event:

The cause of the maximum thermal power exceeding the license condition limit was inaccurate- span correction factors provided by Rosemount Inc., the manufacturer of the differential pressure transmitter (SALP Cause Code B: Design, Manufacturing, Installation Error). As a result, the calibration procedures insufficiently compensated for- the effect of static pressure which in turn resulted in the actual feedwater flow rate being greater

4l I+I UCENSEE EVENT REPORT (LER) TEXT CONllNUATION PAOE FAClllTTNAME BEQUEMIAL REVIBION

. NUMBEA NUMBEA TEXT'sooo52892 Palo Verde. Unit 1

01'4 0 0'04 oF 0 5 than the indicated value. Since the feedwater flow rate is to the secondary calorimetric and the secondary, calorimetrican'nput is used to calibrate primary thermal power, the inaccurate correction, factor may have. resulted in thermal power exceeding the license condition limit.

No unusual characteristics of the work 'location,(e.g , noise, heat, poor lighting) directly contributed to this event. No procedural nor personnel errors contributed to this event.

J. Safety System Response:

Not applicable - there were no safety system responses and none were'ecessary.

K. Failed Component Information:

No component failures were involved;,however, the affected differential transmitters were manufactured by Rosemount, model number 1152.

ASSESSMENT OF THE SAFETY CONSEQUENCES AND IMPLICATIONS OF THIS EVENT:

The event di'd not result in any challenges to the fission product, barriers or result 'in any releases of radioactive material's. The maximum 0.2 -percent power increase is significantly smaller than the nominal instrument uncertainties bounding the accident analyses.

Therefore, no adverse safety consequences or implications resulted from this event, nor,did this event adversely affect the safe operation of the plant or the health and safety of the public.

III. CORRECTIVE ACTION:

A. Immediate:

Indicated power was reduced .to 99.5 percent power for Unit 1 and 2 (Unit 3 is currently in a refueling outage).

Action to Prevent Recurrence:

The applicable information from the"'10CFR21 notification was incorporated in the technical manual for'the Rosemount differential pressure transmitter,. Model -1152. ,The procedures for the calibration of the affected transmitters have been revised to incorporate the new correction factors.

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LICENSEE EVENT REPORT (LER) TEXT CONTINUATION r

FACIUTY NAME PAOE i BEOUENTIAL NUMBER REVISION NUMBER Palo Verde Unit 1 06000528 9I2 0 1 4 0 0 0 5 OF 05'he algorithm for the secondary- calorimetric. was modified in Units 1 and 2 to compensate for the inaccurate correction factors such that the indicated thermal power is'onsistent with .actual thermal power. This modification will remain effective until the-differential pressure transmitters are recalibrated. The transmitters in Unit 3 will be recalibrated using the revised procedures 'prior to startup from the current Unit 3 refueling outage.

IV. PREVIOUS SIMILAR EVENTS:

No other previous events have been reported pursuant to 10CFR50.73 where the licensed power limit was exceeded as a result of inaccurate data form the vendor.

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