ML17312A775

LER 96-003-00:on 960122,missed Surveillance for Logic Check of Logs 1 & 2 Safety Excore Bypasses.Caused by Procedural Error.Log Power Functional Test Revised to Check Logs 1 & 2 Bypasses Regardless of Power level.W/960517 Ltr

ML17312A775
Person / Time
Site:	Palo Verde
Issue date:	05/17/1996
From:	Grabo B, James M. Levine ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
192-00969-JML-B, 192-969-JML-B, LER-96-003, LER-96-3, NUDOCS 9605280258
Download: ML17312A775 (12)

Text

CATEGORY 1 REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDE)

ACCESSION NBR:9605280258 DOC.DATE: 96/05/17 NOTARIZED: NO FACIL:STN-50-529 Palo Verde Nuclear Station, Unit 2, Arizona Publi DOCKET I 05000529 AUTH. NAME AUTHOR AFFILIATION GRABO,B.A. Arizona Public Service Co. (formerly Arizona Nuclear Po~er LEVINE,J.M. Arizona Public Service Co. (formerly Arizona Nuclear Power RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 96-003-00:on 960122,missed surveillance for logic check of log 1 & 2 safety excore bypasses. Caused by procedural error.Log Power Functional test revised to check Log 1 a 2 bypasses regardless of power level.W/960517 ltr.

DISTRIBUTION CODE: ZE22T COPIES RECEIVED:LTR I ENCL I SIZE:

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

NOTES:Standardized plant. 05000529 @

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD4-2 PD 1 1 CLIFFORD,J 1 1 INTERNAL: ACRS 1 1 A AB 2 2 AEOD/SPD/RRAB 1 1 ILE CENTE 1 1 NRR/DE/ECGB 1 1 ELB 1 1 NRR/DE/EMEB 1 1 NRR/DRCH/HHFB 1 1 NRR/DRCH/HICB 1 1 NRR/DRCH/HOLB 1 1 NRR/DRCH/HQMB 1 1 NRR/DRPM/PECB 1 ~

1 NRR/DSSA/SPLB 1 1 NRR/DSSA/SRXB 1 1 D

-RES/DSIR/EIB 1 1 RGN4 FILE 01 1 1 EXTERNAL: L 'ST IOBBY WARD 1 1 LITCO BRYCE,J H 2 2 NOAC MURPHY,G.A 1 1 NOAC POORE,W. 1 1 NRC PDR 1 1 NUDOCS FULL TXT 1 1 E

N NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM OWFN 5D-5(EXT. 415-2083) TO ELIMINATE YOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 26 ENCL 26

I Arizona Public Service Company PALO VERDE NUCLEAR GENERATING STATION P.O. BOX 52034 ~ PHOENIX, ARIZONA 85072-2034 192-00969-JML/BAG/DLK JAMES M. LEVINE May 17, 1996 VICE PRESIDENT NUCLEAR PRODUCTION U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Station P1-37 Washington, DC 20555-0001

Subject:

Palo Verde Nuclear Generating Station (PVNGS)

Unit 2 Docket No. STN 50-529 License No. NPF-51 Licensee Event Report 96-003-00 Attached please find Licensee Event Report (LER)96-003 prepared and submitted pursuant to 10CFR50.73. This LER reports a condition that resulted in a missed surveillance. The surveillance test used to check the Log 1 and Log 2 Safety Excore channel bypass logic did not require the logic to be checked when reactor power was above 1E-4 percent; so when the surveillance test was performed at 100 percent power on January 19, 1996, the Log 1 and Log 2 bypass logic was not checked. On January 22, 1996, when Unit 2 changed MODES from 3 to 2, the test was recognized as a full credit test. In reality, Surveillance Requirement 4.3,1.2 for bypass testing was not satisfied, and the plant's Technical Specifications were violated. All Units are currently in compliance.

In accordance with 10CFR50.73(d), a copy of this LER is being forwarded to the Regional Administrator, NRC Region IV. If you have any questions, please contact Burton A. Grabo, Section Leader, Nuclear Regulatory Affairs, at (602) 393-6492.

Sincerely, JML/BAG/DLK/pv Attachments cc: L. J. Callan (all with attachments)

K. E. Perkins K. E. Johnston INPO Records Center PDR 280258 960517 ADOCK 05000529 J

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LICENSEE EVENT REPORT (LER)

FACILITYNAME (1) ~

OOCKETNUMBER(2) PAGE (3)

Palo Verde Unit 2 0 5 0 0 0 5 2 9 1oFO 4 ITLE (4)

Missed Surveillance for Logic Check of Log 1 and Log 2 Safety Excore Bypasses EVENT DATE 6 LER NUMBER 6 REPORT DATE 7 OTHER FACILITIES INVOLVED 6 MONTH YEAR YEAR SEQUENTIAL 4~<; REVISIOM MONTH DAY YEAR FACIUTY NAMES KET NUMBERS Vga'UM BF R Pygmy NUMBER N/A 0 1 2 2 9 6 9 6 0 0 3 0 0 0 5 1 7 9 6 N/A OPERATING (HIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR L; (Check one o, more ol the toaowep) (11)

MODE (6) 20,402(b) 20.405(c) 50.73(aX2Xrv) 73.71(b) 3 POWER 20 405(aX1Xi) 50.36(cX I ) 50.73(sX2Xv) 73.71(c)

LEVEL(10) 0 20.405(aX1Xii) M.36(cX2) 50.73(aX2XYTT) OTHER (Specrty h Abstract 20,405(sX1Xii) 50,73(sX2Xi) 50.73(sX2XvwXA) below snd e TexL NRC Fohn 20.405(sX1Xiv) 50.73(aX2Xx) 50.73(aX2XviYiXB) 20.405(a X I Xv) 50.73(aX2Xii) 50.73(aX2Xx)

LICENSEE CONTACT FOR THIS LER (12)

AME ELEPHONE NUMBER EA CODE Burton A. Grabo, Section Leader, Nuclear Regulatory Affairs 6 0 2 3 9 3 - 6 4 9 2 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPOR T (13)

CAUSE SYSTEM COMPONENT MANUFAC REPORTABLE CAUSE SYSTEM COMPONENT MANUFAC REPQRTABLE TURER TO NPRDS N4k~>A . k TURER NPRDS j>Mv.'K~sT6x'j:'('O IN@%a~aSA:&SIC v'Pk" "'F~'453 SUPPLEMENTAL REPORT EXPECTED (14) EXPECTED MONTH DAY YEAR SUBMISSION YES (II yes, Complete EXPECTED SUBMISSION DATE) NO DATE (15)

X BSTRAGT (Lena to 1400 spaces.I.e., approximately filteen aegis-space typewrxten lees) (16)

On January 22, 1996, at approximately 1507 MST, Palo Verde Unit 2 was in MODE 3 at normal operating temperature and pressure when Control Room personnel entered MODE 2. The MODE change was made based on a verified MODE change checklist that included a deficient procedure. The Log 1 and Log 2 Safety Excore channel bypasses are checked as part of the Log Power Functional test; however, the bypass logic was not required to be checked during tests performed at power levels greater than 1E-4 percent. The Log Power Functional Test was last performed on January 19, 1996, when power level was approximately 100 percent. By procedure, the bypass logic was not checked, and the test was credited as a complete surveillance. On January 22, 1996, Control Room personnel recognized the test as a full credit surveillance and proceeded with the startup to MODE 1. Entering MODE 2 without a current logic check of the Log 1 and Log 2 bypasses was a violation Technical Specification Surveillance Requirement 4.3.1.2:

The cause of the event was a deficient surveillance test procedure in that the test was considered a full credit test even though, by procedure, the logic for the Log 1 and Log 2 bypasses was not checked.

As corrective action, the Log Power Functional test was revised to check the Log 1 and Log 2 bypasses regardless of power level.

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LICENSEE EVENT REPORT (LER) TEXT CONTINUATION ACILITYNAME DOCKET NUMBER LER NUMBER PAGE YEAR >~/', SEQUENTIAL EVISIO NUMBER NUMBER Palo Verde Unit 2 0 5 0 0 0 5 2 9 9 6 0 0 3 0 0 0 2 of04 1 . REPORTING REQUIREMENTS:

This LER 529/96-003-00 is being written to report a condition prohibited by the plant's Technical Specifications as specified in 10CFR50.73(a) (2) (i) (B) .

Specifically, at approximately 1507 MST on January 22, 1996, Palo Verde Unit 2 was in MODE 3 (HOT STANDBY) at normal operating temperature and pressure when Control'oom personnel (utility, licensed) entered MODE 2 (STARTUP) . The MODE change was made based on a verified MODE change checklist that included a deficient procedure. As a result of the deficient procedure, the logic checks on the Log 1 and Log 2 Safety Excore (IG) channel bypasses (JC) were not current when Unit 2 entered MODE 2.

Entering MODE 2 without current logic checks of the Log 1 and Log 2 bypasses was a violation of Technical Specification Surveillance Requirement 4.3.1.2 which states in part:

"The logic for the bypasses shall be demonstrated OPERABLE prior to each reactor (AC) startup unless performed during the preceding 92 days."

2. EVENT DESCRIPTION:

On January 22, 1996, Control Room personnel were starting up Unit 2, following an automatic reactor trip that occurred on January 21, 1996 (LER 529/96-001). During the MODE change from 3 to 2, Control Room personnel verified that the applicable MODE change checklist was complete; however, one of the procedures listed on the checklist was deficient. The Log 1 and Log 2 Safety Excore channel bypasses are checked as part of the Log Power Functional test except when the test is performed at power levels greater than" 1E-4 percent. The Log Power Functional Test was last performed on January 19, 1996, when power level was approximately 100 percent. By procedure, the bypass, logic (JC) was not checked, and the test was credited as a complete surveillance. On January 22, 1996, Control Room personnel recognized the test as a full credit surveillance and proceeded with the startup to MODE 1 (POWER OPERATION).

Unit 2 continued to operate in MODE 1 until March 16, 1996, when the reactor was manually shut down for a refueling outage. On March 18, 1996, during a routine procedure revision review, an I&C Maintenance Advisor questioned the adequacy of the Log Power Functional test to satisfy

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION AGILITYNAME DOCKET NUMBER LER NUMBER PAGE YEAR ~g:. SEQUENTIAL '<p EVISIO NUMBER <)(~ NUMBER Palo Verde Unit 2 ) NN:

0 5 0 0 0 5 2 9 9 6' 0 3 0 0 0 3 of 0 4 EXT Surveillance Requirement 4.3.1.2. A Condition Report Disposition Request was initiated which prompted an investigation. On April 18, 1996, the preliminary investigation concluded that logic checks of the Log 1 and Log 2 bypasses were required prior to MODE 2 entry on January 22, 1996, because the last test that checked the bypass logic was performed on July 18, 1995, which exceeded the 92 days prior to startup Technical Specification provision. Unit 2 was in MODE 5 (COLD SHUTDOWN) with the reactor trip breakers (AA) opened when the missed surveillance was discovered. As such, the Log 1 and Log 2 bypasses were not required to be OPERABLE. The Log 1 and Log 2 bypasses were verified to be OPERABLE in Units 1 and 3. The preliminary investigation also concluded that the cause of the missed surveillance was a procedural deficiency that existed since the start of commercial operation. A review of Units 1, 2, and 3's archived Log Power Functional tests for the past three years was performed to determine the extent of the problem. No additional missed surveillances were identified.

3. ASSESSMENT OF THE SAFETY CONSEQUENCES AND THE IMPLICATIONS OF THIS EVENT:

The Log 1 bypass is provided to manually bypass the High Log Power trip (JC) when reactor power level is greater than 1E-4 percent to facilitate power operations. The 'safety function of the Log 1 bypass bistable is to automatically remove the trip bypass when reactor power level falls below 1E-4 percent. Conversely, the Log 2 bypass is provided to manually bypass the Low Departure from Nucleate Boiling Ratio (DNBR)/High Local Power Density (LPD) trip (JC) when reactor power is less than 1E-4 percent to facilitate reactor startups. The safety function of the Log 2 bypass bistable is to automatically remove the bypass. when reactor power increases above 1E-4 percent. There are four Safety Excore channels, each channel contains a Log 1 and Log 2 bypass bistable. Each channel controls the bypass function for the Log Power, and DNBR/LPD bypasses iri it' associated channel. Past surveillance tests have demonstrated the bypass bistables to be highly reliable. Because of the number of redundant system channels and previous history of satisfactory surveillance testing, the safety consequences of failing to perform the required surveillance test on the Log 1 and Log 2 bypass bistables prior to MODE 2 entry on January 22, 1996, was very low. Surveillance testing performed on the Log 1 and Log 2 bypasses subsequent to the January 22, 1996 event was satisfactory.

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION AGILITYNAME DOCKET NUMBER LER NUMBER PAGE

'egg SMUENTIAL @'~< EVISIO

'~~@. NUMBER NUMBER Palo Verde Unit 2 $$ .

TEXT 0 5 0 0 0 5 2 9 9 6 0 0 3 0 0 04of 0 4 The event did not result in any challenges to the fission product barriers or result in any releases of radioactive materials. This event did not adversely affect the safe operation of the plant or the health and safety of the public.

4. CAUSE OF THE EVENT:

An independent investigation of this event was conducted in accordance with the APS Corrective Action Program. Based on the results of the investigation, the cause of the event was attributed to procedural error (SALP Cause Code D: Defective Procedures). The procedure deficiency had existed since the start of commercial operation. No unusual characteristics of the work location (e.g., noise, heat, poor lighting) directly contributed to this event.

5. STRUCTURES, SYSTEMS, OR COMPONENT INFORMATION:

No structures, systems, or components were inoperable at the start of the event that contributed to the event. No component or system failures were involved. No failures of components with multiple functions were involved. No failures that rendered a train of a safety system inoperable were involved. There were no safety system responses and none were necessary.

CORRECTIVE ACTION TO PREVENT RECURRENCE:

The applicable surveillance test was revised on April 19, 1996, to implement a new method of testing the Log 1 and Log 2 bypass logic for the Safety Excore channels. The new test. method ensures the Log 1 and Log 2 bypass logic is checked during each scheduled performance, regardless of plant power levels.

7. PREVIOUS SIMILAR EVENTS:

There have been no previous similar events reported pursuant to 10CFR50.73 in the last three years.