ML20044F574

LER 93-006-00:on 930418,safety Injection Initiated During Slave Relay Testing.Caused by Personnel Error.Team Reminded to Request Assistance When Operational Questions Arise.W/ 930517 Ltr

ML20044F574
Person / Time
Site:	Vogtle
Issue date:	05/17/1993
From:	Mccoy C, Sheibani M GEORGIA POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LCV-0008, LCV-8, LER-93-006, LER-93-6, NUDOCS 9305280270
Download: ML20044F574 (5)

Text

Gemga Power Compriy 40 l'wemen Cenw Pahay

. Pon: 0"ce G a 1295 Bemergham. Ata* an.a 35201 To.eproye 2D5 6773122 m

C. K. McCoy Georeiav Power Vce Puscent Nx+c Vo@e Prejed IT Cot,1 hero ehrtT system LCV-0008 Docket No. 50-424 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555 Gentlemen:

VOGTLE ELECTRIC GENERATING PLANT LICENSEE EVENT REPORT S AFETY INJECTION INITIATED DURING SLAVE RELAY TESTING In accordance with the requirements of 10 CFR 50.73, Georgia Power Company submits the enclosed report related to an event which occurred on April 18,1993.

Sincerely, C. K. McCoy

/

/

CKM/NJS

Enclosure:

LER 50-424/1993-006 xc: Georgia Power Company Mr. W. B. Shipman Mr. M. Sheibani NORMS U. S. Nuclear Reculatory Commission Mr. S. D. Ebneter, Regional Administrator Mr. D. S. Ilood, Licensing Project Manager, NRP.

Mr. B. R. Bonser, Senior Resident Inspector, Vogtle P80 0 7. 3

BP EEE E8Skg4 e .

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nn 0:4 U.5. N 1 LLAn RLUd M Y n m lbhiUN AryH i GiO4 LICENSEE EVENT REPORT (LER) l I

l iALitiin hAML (1) UULAti hbMets (2) Fw 131 l VOGTE ELECIRIC GDERATING PIANT - UNIT 1 05000424 1l0Fl4  !

IllLE (4)

SAFL'IY IlUECTION INITIATED DURUE SIAVE REIAY TESTUC '

EVEh1 DATE (5) LER huMBER [6) REPCkl DATE (7) OTHER FACILITIES Ihv0LVED (8)

MGkIN DAV VLAR VEAR 5EQ hbM REW m0h1M DAY YEAR FACILITY hAME5 DOCAET h0MBEk(5)

O5000 04 18 93 93 006 00 05 17 93 05000 CPERATlhG IMS nN 15 M M h*M M M WMMBS M M UR [H)

MODE (9) 5 20.402(b) 20.405(c) ^ 50.73(a)(2)(iv)

_ 73.71(b)

POUER 20.405(a)(1)(1) -

50.36(c)(1) -

50.73(a)(2)(v) 73.71(c)

LEVEL 0 20.405(a)(1)(ii) T OTHER (Specify in 50.36(c)(2) 50.73(a)(2)(vii) 20.405(a)(1)(tii) 50.73(a)(2)(1) -

50.73(a)(2)(viii)(A) Abstract below) 20.405(a)(1)(iv) ~~

50.73(a)(2)(ti) 50.73(a)(2)(vi11)(B) Tech. Spec.

20.405(a)(1)(v) 50.73(a)(21(111) 50.73(a)(2)(x) Special Report LICEh5EE C0hlAC1 FOR THis LER (li)

NAME TELEPN0hE huMBER LREA CODE MDIDI SHEIBANI. NUCIIAR SAFEIY AND COMPLIANCE 706 826-3209 COMPLETE Cht LIhE FOR EACH FAILURE DE50RlbED Ih IN15 REP 0kT (13) ,

CAUSE SYSTEN COMP 0hENT MAhurAC- R P0RT CAUSE SYSTEM COMFONENT R PORT TU pgD5 jANUFAC-ggER SUPPLEMENTAL kEPORI EXPECIED (14; M0hTN DAY 1 EAR EXPECTED SUBMISSION

] YES(If yes coniplete EXPECTED SUBMISSION DATE) "E] h0 DATE (15)

AE51RACT (16)

On April 18, 1993, while in cold shutdown, the solid state protection system (SSPS) mode selector switch was taken to " Operate" in order to support slave relay testing. Immediately, the SSPS processed a safety injection (SI) signal due to low pressurizer pressure and low steamline pressure. At the time that the mode selector switch was taken to " Operate," SI actuation should have been blocked. However, due to work in progress that affected the pressurizer pressure instrumentation channels, automatic unblock permissive conditions were present. Control room operators recognized the inadvertent SI signal and responded to reduce injection flow and restore the normal charging system flowpath. Because this actuation had resulted in emergency core cooling system discharge to the RCS, and operators had returned the unit to normal operation, a Notification of Unusual Event was both declared and terminated at 0824 EDT.

The cause of this event was a personnel error on the part of the control room team for allowing the SSPS to be returned to service when a SI signal would not be blocked. Contributing to this was the large number of activities occurring as restoration of plant systems took place following the refueling. The crew did not fully evaluate the impact of other maintenance activities on this procedure. The team was reminded to request assistance when operational questions arise and/or to take sufficient time for review prior to changes in  ;

the configuration of plant systems.

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LICENSEE EVENT REPORT (LER) )

TEXT CONTINUATION ,

FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (5) PAGE (3) l YEAR SEQ NUM REV  :

V0GI1E ELECIRIC GDUATING PLANT - UNIT 1 05000424 93 006 00 2 or 4 j TEXT i A. REQUIREMENT FOR REPORT f This report is required per 10 CFR 50.73 (a)(2)(iv) because an unplanned. l engineered safety feature (ESF) actuation occurred when a safety injection i (SI) signal resulted in an emergency core cooling system (ECCS) discharge j into the reactor coolant system (RCS). It is also required per Technical  !

Specification 3.4.9.3, because residual heat removal (RHR) suction relief. l valves opened to mitigate an RCS pressure transient.  :

1 B. UNIT STATUS AT TIME OF EVENT i i

At the time of this event, Unit 1 was in Mode 5 (cold shutdown) at 0 percent l of rated thermal power for a refueling outage. The RCS was solid.with a  !

temperature of 120 degrees F and a pressure of 345 psig. Other than that described herein, there was no inoperable equipment which contributed to the occurrence of this event. j i

C. DESCRIPTION OF EVENT j On April 18, 1993, personnel were preparing to perform slave relay testing j per Procedure 14606-1, " Slave Relay K618 Train A Test Safety. Injection." For j this test, the solid state protection system (SSPS) is required to be in  !

service. To ensure that no unnecessary. actuation would occur when placing  !

the SSPS in service. a control room operator checked the bypass permissives  :

light board (BPLB) and found that all required blocks were illuminated l However, two of the three pressurizer pressure channels were also in trip.due  !

l to other work that was in progress at the time. As a result, the leetc for j the P-11 safety injection automatic unblock permissive was complete.  ;

Therefore, at 0756 EDT, when the operator took the Train A SSPS mode selector  !

switch to " Operate," the SSPS processed an SI signal for Train A due to low- i pressurizer pressure and low steamline pressure, conditions which are always [

present during cold shutdown, but normally blocked. Control room operators recognized the inadvertent SI signal and responded to reduce injection flow i and restore the normal charging system flowpath. This action and the-lifting  ;

of the residual heat removal (RHR) suction relief valves at approximately {

450 psig, as designed, prevented any serious RCS pressure transient from i occurring. After the required 60-second delay for SI signal processing, the l SI actuation signal was reset, and normal unit operation was restored.

Because this actuation had resulted in ECCS discharge to the RCS and operators had returned the unit to normal operation, a Notification of ,

Unusual Event was both declared and terminated at 0824 EDT, and appropriate  !

notifications were completed.

D. CAUSE OF EVENT l The cause of this event was a personnel error on the part of the control room f team for allowing the SSPS to be returned to service when a S1 signal would not be blocked. The control room team, led by the unit shift supervisor I (USS), questioned among themselves the action of placing the SSPS in  !

" Operate." The error oc::urred when the crew placed the SSPS switch to ).

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LICENSEE EVENT REPORT (LER) l TEXT CONTINUATION i FACILITT NAME f3) DOCKET NUMBER (2) LER NUMBER (b) PAGE (3)

YEAR SEQ hum REV  ;

VDGI1E ELECIPJC GmTRATING PIANI - INIT 1 05000424 93 006 00 3 0F 4 -

TEXT f operate even though they had not resolved their initial concern or completed f a full assessment of current plant conditions. There were no unusual  !

characteristics of the work loca cion that contributed to the occurrence of  ;

this error by the Georgia Power Company personnel involved. .

i Contributing to the cause of this event was the large number of activities {'

which were occurring as restoration of plant systems took place following the refueling. l Also contributing to the cause of this event was a procedure which was not  !

written to be performed under the plant conditions that existed when the SSPS ,

was returned to service. Procedure 13503-1, " Reactor Control Solid State  ;

Protection System," did not provide the information that the BPLB indications  ;

may not reflect all necessary blocking conditions. This procedure directed i operators to ensure that the pressurizer low pressure SI signal and the steamline low pressure SI signal were blocked. Handswitch designations are provided to ensure the blocks are initiated if necessary. Operators use  !

block status light indicatiens to verify that the block is in effect. When  ;

the SSPS is in " Test," the status lights will illuminate when their associated block switches are placed in block, even if plant conditions are  :

above P-ll (or process inputs are tripped, simulating conditions above'P-11). l If actual P-11 conditions are not met when the SSPS is placed in " Operate,"  !

the block is removed. Additionally, if the SSPS logic is met for an SI i condition, an SI would result when the SSPS is taken to " Operate," as occurred on April 18, 1993, because P-11 will automatically unblock the l actuation signal. The operating procedure in use did not provide adequate l precautionary guidance to the operators to warn them of the potentially misleading indications, and it did not provide other guidance to ensure that l P-11 conditions were met and the SI signals were appropriately blocked. .

E. ANALYSIS OF EVENT I The SI signal was not valid since no condition requiring an SI existed.  !

Additionally, operators responded properly to divert the Train A charging l pump flowpath from the RCS. This action and the lifting of the residual heat  ;

removal (RHR) suction relief valves at approximately 450 psig, as designed,  !

prevented any serious RCS pressure transient from occurring. The Train B j SSPS was out of service due to work in progress, and the SI pumps were inoperable in accordance with the Technical Specifications. The Train A RHR l system was in the shutdown cooling mode of operation. Consequently, only the l Train A centrifugal charging pump injected water into the RCS. Therefore, no excessive pressure condition occurred in the RCS. This event could not have j occurred while the unit was at power because the SSPS must already be  ;

operable prior to resuming power operations and because RCS pressure remains  ;

above 2000 psig during power operations. Based on these considerations, -!

there has been no adverse effect on plant safety or on the health and safety l of the public as a result of this event. j 1

I

u.s. uwm eanum w.n>im g ,nuA ungggpix LICENSEE EVENT REPORT (IZR)

TEXT CONTINUATION FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (5) PAGE (3)

VEAR 5EQ hum REW V0GIE ELICIRIC GDDATING PIANT - LWIT 1 05000424 93 006 00 4 0F 4 lEXl F. CORRECTIVE ACTIONS i

1. The team was reminded to request assistance when operational questions arise and/or to take sufficient time for review prior to changes in the configuration of plant systems.

2. A caution was added to Procedure 13503-1 to warn operators of the potential for an SI when taking the SSPS to " Operate."

3. By July 1,1993 Procedures 13503-1 and 13503-2 will be further enhanced to require verification that conditions within the SSPS are established to permit blocking of the SI signal.

4. The details of this event will be reviewed as a " Lesson Learned" in licensed operator requalification training.

G. ADDITIONAL INFORMATION

1. Failed Components None t

2. Previous Similar Events ,

LER 50-425/1992-004, dated May 11,1992.

Corrective actions from this earlier LER addressed specific solutions that were not applicable for the prevention of the April 18, 1993, SI event.

3. Energy Industry Identification System Code Solid State Protection System - JG Reactor Coolant System - AB .

120 Volt AC 1E Power System - ED Safety Injection System - BQ Main Steam System - SB

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