ML20046C490

LER 93-019-00:on 930709,determined That TS Requirement of MSIV Was Not Met Due to Inadequate Design of Field Change to Testing Function of Solid State Protection Sys.Corrected Missing Jumpers & Overlap Testing discrepancy.W/930805 Ltr

ML20046C490
Person / Time
Site:	South Texas
Issue date:	08/05/1993
From:	Cloninger T, Pinzon J HOUSTON LIGHTING & POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-93-019, LER-93-19, ST-HL-AE-4536, NUDOCS 9308110073
Download: ML20046C490 (7)

Text

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The Light  !

c o m p a n yS uth Texas Project Electric Generating P. O. Station Box 289 Wadsworth, Texas 77483

^

Ilouston Lighting & Power l

l August 5, 1993 ST-HL-AE-4536 '

File No.: G26 10CFR50.73 i

U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 South Texas Project Unit 1 Docket No. STN 50-498 Licensee Event Report 93-019 Failure to Meet Technical Specification Surveillance Testing Reauirements of the Main Steamline Isolation Valve Pursuant to 10CFR50.73, Houston Lighting & Power (HL&P) submits the attached Unit 1 Licensee Event Report 93-019 regarding the identification by HL&P personnel that a Technical Specification requirement was not being met with regards to surveillance testing of the Main Steamline Isolation Valve. This event did not have an adverse effect on the health and safety of the public. -

If you should have any questions on this ma , please contact Mr. J. M. Pinzon at (512) 972-8027 or me at 972-8787.

s T. H. Cl ninge Vice Preside ,

Nucle E inee ing JMP/pa

Attachment:

LER 93-019 (South Texas, Unit %

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100052 o I c LER-93\L93019RO.U1- .

Project Manager on Behalf of the Participants in the South Texas Project / [ '

9308110073 930709 * #

PDR ADOCK.05000498 +

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Houston Lighting & Power Company South Texas Project Electric Generating Station ST-HL-AE-4536 File No.: G26 Page 2 c:

Regional Administrator, Region IV Rufus S. Scott Nuclear Regulatory Commission Associate General Counsel 611 Ryan Plaza Drive, Suite 400 Houston Lighting & Power Company Arlington, TX 76011 P. O. Box 61867 Houston, TX 77208 L. E. Kokajko Project Manager U.S. Nuclear Regulatory Commission Institute of Nuclear Power Washington, DC 20555 Operations - Records Center 1100 Circle 75 Parkway D. P. Loveless Atlanta, GA 30339-3064 Senior Resident Inspector c/o U. S. Nuclear Regulatory Dr. Joseph M. Hendrie Commission 50 Bellport Lane P. O. Box 910 Bellport, NY 11713 Bay City, TX 77414 D. K. Lacker J. R. Newman, Esquire Bureau of Radiation Control Newman & Holtzinger, P.C., Ste. 1000 Texas Department of Health 1615 L Street, N.W. 1100 West 49th Street Washington, DC 20036 Austin, TX 78756-3189 D. E. Ward /T. M. Puckett U.S. Nuclear Regulatory Comm.

Central Power and Light Company Attn: Document Control Desk P. O. Box 2121 Washington, D.C. 20555 Corpus Christi, TX 78403 J. C. Lanier/M. B. Lee City of Austin Electric Utility Department 721 Barton Springs Road Austin, TX 78704 K. J. Fiedler/M. T. Hardt City Public Service P. O. Box 1771 San Antonio, TX 78296 LER-93\t93019RO.U1

NRC FORM 366 U.S. NUCLEAR REQJLATOR7 COPO41SSION APPPOVED BT OMB NO. 3150-0104 (5 92) EXPIRES 5/31/95 ESilMATED BURDEN PER RESPONSE TO CCNPLY WITH I

LICENSEE EVENT REPORT (LER) $4an"NgNfS 3 RE ARDIN BURDEN ST MATE b THE INFORMATION AND RECORDS MANAGEMENT BRANCH (MNBB 7714), U.S. NUCLEAR REGULATORY COMMISSION, (See reverse for required rmber of digits / characters for each block) WASHINGTON, DC 20555-0001, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY MAE (1) DOCKET NUMBER (2) PAGE (3)

South Texas, Unit 1 05000 498 1 OF 5 TITLE (4) Failure to Meet Technical Specification Surveillance Testing T?nmii v nmente: of thn Main Stnamlinn T e-nl a t i on Valve EVENT DATE (5) LER NUMBER (6) REPORT DAl' (7) OTHER FACILITIES INVOLVED (8)

RE S FACILITY NAME DOCKET NUMBER SE AL MONTH DAY YEAR YEAR MONTH DAY YD.R $outh Texas, Unit 2 05000 499 F M NAME D Crn "

07 09 93 93 -- 019 -- 00 08 05 93 0 0 OPERATING TH 3 REN M MMIHH) NUANT TO THE RNWNM OF 10 CR D (C%ck one or m) (M)

C'DDE (9)

$ 20.402(b) 20.405(c) 50.73(a)(2)(iv) 73.71(b)

POWER * *" " '

0 20.405(a)(1)(li) 50.36(c)(2) 50.73(a)(2)(vii) OTHER LEVEL (10) 20.405(a)(1)(lii) X 50.73(a)(2)(i) 50.73(a)(2)(viii)(A) (Specify in Abst act ow 20.405(a)(1)(iv) 50.73(a)(2)(ii) 50.73(a)(2)(vill)(B) ,

20.405(a)(1)(v) 50.73(a)(2)(ill) 50.73(a)(2)(x) NRC Form 366A)

LICENSEE CONTACT FOR THis (ER (12)

NAME TELEPHONE NUMBER (Include Area Code)

Jairo Pinzon - Senior Engineer (512) 972 - 8027

[ COMPLETE ONE lINE FOR EACH CIMPONENT FAltuRE DESCRIBED IN THIS REPORT (13)

CAUSE SYSTEM COMPONENT MANUFACTURER CAUSE SYSTEM COMPONENT MANUFACTURER B JG ECBD W120 NO SUPPLEMENTAL REPORT EXPECTED (14) MONTH DAY YEAR EXPECTEI)

YES (If yes, cocplete EXPECTED SUBMISSION DATE). X NO E 1 ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16)

On July 9, 1993, Unit 1 was in Mode 5 at 0% power and Unit 2 was defueled in a refueling outage. HL&P personnel determined that a Technical Specification requirement was not being met in that the actuation logic surveillance test for the Main Steamline Isolation Valves (MSIV) had not been completely implemented. During a design review of the Solid State Protection System (SSPS) wiring, the System Engineer discovered that the Logic Test for the MSIV Actuation function failed to perform a continuity test through the final output device (Master Relays) as required by the Technical Specification 1.2 definition of a Logic Test. Technical Specification 4.3.2 requires that a monthly surveillance of the Steamline Isolation Actuation Logic and Actuation Relays be performed. The surveillance test previously performed had failed to meet the Technical Specification requirements. The cause of this event was an inadequate design of the testing function of the Solid State Protection System with regards to the Main Steamline Isolation Valve. Corrective actions include performing a review of all SSPS design changes related to logic circuitry for proper design.

Wat FOkN 366 (R2)

LER-93\L93019RO.U1

NRC FORM 366A U.S. NUCLEAR REGULATORY CDetISSION l APPRWED BY GB No. 3150-0104 (5-92) l EXPIRES 5/31/95 ESTIMATED BU DEN PER RESPONSE TO COMPLY WITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS.

LICENSEE EVENT REPORT (LER) Non$Tf0N AND RECORD "kAIAGE4N BR NCH M TEXT CONTINUATION 7714), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555-0001 AND TO THE PAPERWORK REDUCTION PROJECT (3180-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY EAK (1) DOCKET Nt.MBER (2) LER NLMBER (6S PAGE (3)

SEQUENTIAL REVISION YEAR South Texas, Unit 1 05000 498 2 OF 5 93 -- 019 -- 00 TEXT tif more space is reautred. use additional cooles of NRC Form 366A) (17)

DESCRIPTION OF EVENT:

On July 9, 1993, Unit 1 was in Mode 5 and Unit 2 was defueled in a refueling outage. HL&P personnel determined that a Technical Specification requirement was not being met in that the actuation logic surveillance test for the Main Steamline Isolation Valves (MSIVs) had not been properly implemented. During a design review of the Solid State Protection System (SSPS) wiring, the System Engineer discovered that the Logic Test for the Main Steamline Actuation function failed to perform a continuity test through the final output device (Master Relays) as required by the Technical Specification 1.2 definition of a Logic Test. Technical Specification 4.3.2.1 requires that a monthly surveillance of the Steamline Isolation Actuation Logic and Actuation Relays be performed, and that the Steamline Isolation Actuation Logic be operable in Modes 1, 2 and 3.

The logic test function consists of both a test of the logic circuits and a continuity check of the master relays, when applicable. The logic test involves applying a series of pulses to the logic circuits which represent various combinations of input signals, then verifying that the expected output signal is produced. The continuity check involves switching the power source-to the master relays from a normal 48 VDC supply to a 15 VDC supply, to prevent actuation, and monitoring the voltage level at the logic output driver while the logic test is being conducted. When properly configured, the test circuits will detect incorrect responses to the input pulses if continuity does not exist through the master relays to the 15 VDC source.

The surveillance test previously performed had failed to meet the Technical Specification requirements. The existing configuration did verify that the Steamline Actuation Logic was functional; however, it failed to check continuity of the wiring from the logic output driver to the master relays.

The specific configuration of the test circuit is peculiar to the Westinghouse Three Train SSPS because of the physical separation between the logic cabinets and the actuation trains which contain the master relays. In the more common Two Train SSPS, the location of the test points in the circuit is such that the master relay test verifies continuity all the way from the logic output driver through the master relays and the logic test is not required to perform this verification.

Although the Three Train SSPS test design was intended to provide the required continuity check, a ground jumper had been onitted from the test switch configuration when Westinghouse prepared a Field Change Notice (FCN) to move the Steamline Isolation actuation function to separate master relays from the Safety Injection actuation function in 1986. Other Engineered Safety Features Actuation System (ESFAS) functions at the South Texas Project Electric Generating Station (STPEGS) contain the jumpers necessary to perform the continuity test through the master relays. Only the Steamline Isolation Actuation function was deternined to be inoporable as a result of this wiring design error.

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LER-93u 93019RO.U1

NRC FORM 366A U.S. NUCLEAR CIGULATORY (D MISSION APPROVE ~) SY DMB NO. 3150-0104 (5-92) EXPIRES 5/31/95

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ESTIMATED BURDEX PER RESPCMSE TO COMPLY UITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS.

LICENBEE EVENT REPORT (LER) YO$ff0N AND REC D MANACEMfNT 8R NCH MN TEXT CONTINUATION TM ') , U.S. NUCLEAR REGULATORY C04MISS10N, WASHINGTON, DC 20555-0001 AND TO THE PAPERWORK REDUCTION PROJECT (31$0-0104), OFFICE OF MANAGEMENT AND BUDGET. WASHINGTON, DC 20503.

FACILITY NAME (1) DOCKFT NLMBFR (?) LER HLMBER (61 PAGE (3)

SEQUENTIAL REVISION YEAR South Texas, Unit 1 05000 498 3 OF 5 93 -- 019 -- 00 TEXT (If more socce is reautred use o&Jitional cooles of kRC Form 366A) (17)

DESCRIPTION OF EVENT: (Cont'd)

The Steamline Isolation Actuation function was fully functional during all the time that it was technically inoperable. The deficiency affected only the test circuit , and continuity of the wiring from the logic output drivers to the master relays has been regularly verified during the plant's operating life. Response time tests and Trip Actuating Device Operational Tests (TADOT) are conducted at 18 month intervals. The Response time tests verify continuity through each complete circuit from the logic power supply through the master relays and back to the logic output driver. The TADOT verifies the overall functionality of the Main Steamline Isolation from manual isolation.

Additionally, the master relay test performed on a monthly basis (90 day staggered test interval) checks continuity from the power supply through the master relay by actually energizing the master relay.

On July 6, 1993, the System Engineer confirmed that the ground jumpers which facilitate a continuity test of the master relays were, in fact, not installed on the test switch positions for the Steamline Isolation Actuation logic test in Unit 1. Although the Westinghouse Technical Manual for the SSPS describes the function of the generic test circuit accurately, the required jumpers did not appear on the interconnection drawings or the wire lists for the Steamline Isolation Actuation function. This omission was consistent across both logic trains in both STPEGS Units.

The NRC was notified of this event on July 9, 1993, at 1719 hours0.0199 days <br />0.478 hours <br />0.00284 weeks <br />6.540795e-4 months <br /> (Central time)

CAUSE OF EVENT:

The cause of this event was an inadequate design of a field change to the testing function of the Solid State Protection System. The original SSPS design actuated Steamline Isolation from the same master relays as are used for Safety Injection. During the plant licensing phase, an agreement was reached with the NRC staff to provide a separate Steamline Isolation Actuation function. Westinghouse prepared a Field Change Notice (FCN) containing design details for the change. This change connected the Steamline Actuation circuits to separate master relays and which would be actuated by a separate logic output driver card. Test circuits were incorporated for the new actuation scheme to provide logic test, master relay test, and _ ave relay test functions. In order to verify continuity through the master relays, as required by the Technical Specification Section 1.2 definition of an Actuation Logic Test, pin 43 of the Test card must be grounded through deck "K" of the test selector switch. The new Steamline Isolation master relay test position contacts on deck "K" should have been jumpered to ground by the FCN instructions; however, no connections were discussed in the instruction or shown in the wire list revision. The SSPS Technical Manual correctly describes operation of the test circuit and mentions the requirements for the grounding of pin 43 via the deck "K" contacts. This event is the result of the omission of the ground jumpers in the FCN instructions and wire list revision.

I LER-93\L93019R0.U1

Mtc FORM 366A U.S. NJCLEAR RECULATORY CupMISSION APPROVED BY oms No. 3150-0104 .

(5-92) EXPIRES 5/31/95 l ESTIMATED BLCDEN PER RESPONSE TO COMPLY WITH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS.

FORWARD COMMENTS RECARDING BURDEN ESTIMATE TO THE

]

, LICENSEE EVENT REPORT (LER) INFORMATION AND RECORDS MANAGEMENT BRANCH (MNBB {

TEXT CONTINUATION 7714), U.S. NUCLEAR REGULATORY COMMISSION, j WASHINGTON, DC 20555-0001 AND TO THE PAPERWORK  ;

REDUCTION PROJECT (3150-0104), OFFICE OF 1 MANAGEMENT AND BUDGET, WASHINGTON, DC 20503,  ;

I FACitITY MAE (1) DOCKET MUMBER (2) Lf R NtDIRER (65 PAGE (3)

SEQUENTIAL REVISION YEAR South Texas, Unit 1 05000 498 4 OF 5 93 -- 019 -- 00 TEKT (1f more sosce is reo; ired, use additional copies of NRC Form 366A) (17) l ANALYSIS OF EVENT:

Failure to completely perform the monthly MSIV actuation logic test surveillance requirement relative to the ESFAS function is reportable pursuant to (2 Both Units did not meet the requirements of 10CFR50.

Technical Specif73 (a) ica) tion (i) (B) .which states that each Engineered Safety 4.3.2.1 Features Actuating System (ESFAS) instrumentation channel and interlock and the automatic actuation logic and relays shall be demonstrated OPERABLE by performance of the ESFAS Instrumentation Surveillance Requirements specified in Table 4.3-2. ,

This deficiency only affects the surveillance testing of the Steamline Isolation Actuation function. The Actuation function itself remained fully functional since the FCN was incorporated. The ability of the actuation logic to generate a Steamline Isolation actuation signal is confirmed through performance of a response time test and an ESF Manual Initiation TADOT every 18 months. Additionally, continuity from each train's logic power supply to the associated master relays is confirmed monthly, on a staggered basis (90 days staggered test interval) by the master relay test. The, master relay test actually energizes the master relays, but does not verify continuity of the complete circuit back to the logic output driver. Because of these assurances that the affected circuits have been fully functional, the risk attributed to this event is considered to be minimal. There were no adverse safety or radiological consequences as a result of this event.

CORRECTIVE ACTIONS:

1. The missing jumpers and overlap testing discrepancy have been corrected in Unit 1. This action will be completed in Unit 2 prior to startup from the current refueling outage.

2. HL&P has performed a review of all Unit 1 SSPS design changes related to logic circuitry for proper design. The original scope of this task was to review FCNs affecting the SSPS logic with a concentration on the differences between the three train design and the standard two train design. The scope was ultimately broadened to look at all FCNs affecting the SSPS. One additional discrepancy was identified in the overlap testing configuration of another logic test scheme (it did not cause a failure to meet a Technical Specifications requirement). The equivalent review will be completed for Unit 2 prior to startup from the current refueling outage.

LER-93\L93019RO.U1 i

NRC FORM 3664 U.s. NUCLEAR REGULATORY CDetISSION APPROWE3 BY (MB No. 3150-0104 (5 92) EXPIRES 5/31/95 ESTIMATED BURDEC PER RESPONSE TO COMPLY WITH VHIS INFORMATION COLLECTION REQUEST: 50.0 HRS.

FORWARD COMMENTS REGARDING BURDEN ESTIMATE To THE

. LICENSEE EVENT REPORT (LER) INFORMATION AND RECORDS MANAGEMENT BRANCH (MNBB TEXT CONTINUATION 771'), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555-0001 AND TO THE PAPERWORK REDUCTION PROJECT (31!!0-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.

FACILITY NAE (1) DOCKET NLMBER (2) LER WUMBER (61 PAGE (3)

YEAR SEQUENTIAL REVISION WWBER NWBER South Texas, Unit 1 05000 498 5 OF 5 93 -- 019 -- 00 TEXT (If more soace is reouired, use additional cooles of NRC For1n 366A) (17)

ADDITIONAL INFORMATION:

The Solid State Protection System was designed and manufactured by Westinghouse.

Unit 2 Voluntary LER 90-009 documented an event in which incorrect wiring was discovered in the SSPS. The cause of this event was inadvertent installation of an extra wire in the SSPS by the manufacturer. Corrective actions included removing the extra wire and successfully testing the system. In addition, the remaining SSPS logic train cabinets on both Units were inspected to verify the absence of this wiring error.

LER 93\L93019R0.U1