ML20045B040

LER 93-010-00:on 930514,unplanned ESF Actuation Occurred Due to Less That Adequate Procedures.Procedures 34SV-B21-001-1S & 34SV-B21-001-2S, MSIV Closure Instrument Functional Test revised.W/930610 Ltr

ML20045B040
Person / Time
Site:	Hatch
Issue date:	06/10/1993
From:	Beckham J, Tipps S GEORGIA POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
HL-3335, LER-93-010, LER-93-10, NUDOCS 9306160144
Download: ML20045B040 (5)

Text

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Geofa Power Company 40 inverness Center Parkway

, Post O* fees Box 1295

- Bwmsngham, Alabama 35201 Telephone 205 877-7279 b I J. T. exkham, Jr. Georgia Power Vce President - Nuclear q Hatch Propct  ??t' D..P+"n Mor fynern June 10, 1993 Docket No. 50-321 HL-3335 005590 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Edwin I. Hatch Nuclear Plant - Unit 1 Licensee Event Report less Than Adequate Procedure Results in Unplanned Enoineered Safety Feature Actuation Gentlemen:

In accordance w'th the requirements of 10 CFR 50.73(a)(2)(iv), Georgia Power Company is submitting the enclosed Licensee Event Report (LER) concerning a less than adequate procedure which resulted in an unplanned Main Steam Isolation Valve closure. This event occurred at Plant Hatch Unit 1.

Sincerely,

. - Jf9%

. T. Beckham, Jr.

OCV/cr

Enclosure:

LER 50-321/1993-010 cc: Georaia Power Company Mr. H. L. Sumner, General Manager - Nuclear Plant NORMS U.S. Nuclear Reaulatory Commission. Washinaton. D.C.

Mr. K. Jabbour, Licensing Project Manager - Hatch U.S. Nuclear Reaulatory Commission. Reaion II l Mr. S. D. Ebneter, Regional Administrator '

Mr. L. D. Wert, Senior Resident Inspector - Hatch  !

l 9306160144 930610 Y I PDR ADOCK 05000321 S PDR a

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U.5. hhlM nu1Adf W%5510h Arv 50-0104 7grm .x;6 LICENSEE EVENT REPORT (LER) rALitliY hAME (1) UQLAti hvMoth (2) FW (4)

PIANT HATCH, UNIT 1 05000321 1 gpl4 ilTLE (4)

LESS THAN ADEIK1 ATE PROCEDURE RESULTS IN USTIANNED ENGINEERED SAFETY FEATURE ACIUATION T vEhI DAIL (5) LER hum 6ER (6) REFORI DATE (7) OTHER F ACILITIES IhWOLVED (6)

M0hTN DAY TEAR TEAR 5E0 hum REV MQhlh DAY YEAR FACILITY hAMES DOCAEI huMBER(5) 05000 05 14 93 93 010 00 06 10 93 05000 OPERAT1hG INIS 60 n MMI E W W 10 M MMMM N 10 m (H) '

MODE (9) 3 20.402(b) 20.405(c) ^ 50.73(a)(2)(iv) 73.71(b)

P08ER -

20.405(a)(1)(i) -

50.36(c)(1) 50.73(a)(2)(v) 73.71(c)

LEVEL 000 20.405(a)(1)(ii) 50.36(c)(2)

~

50.73(a)(2)(vii)

OTHER (Specify in 20.405(a)(1)(iii) 50.73(a)(2)(1) 50.73(a)(2)(viii)(A) Abstract below)

~

20.405(a)(1)(iv) -

50.73(a)(2)(ii) ~

50.73(a)(2)(viii)(B) 20.405(a)(1)(v) 50.73(a)(2)(tii) 50.73(a)(2)(x) +

LICEh5EE CChTACI FOR THIS LER (12)

NAME TELEPn0hE huMBER t l A CODE STEVEN B. TIPPS. MANAGER NUCIIAR SAFEIY AND COMPLIANCE, HATCH 912 367-7851 LOMFLElE GhE LIhE FOR EACn F AILURE DESCRIBED IN IN15 REPORT (13)

CAUSE SYSTEM COMPONENT R P0RT CAUSE SYSTEM COMPONENT NANUFAC- R P RT FAyUFAC-j Ep ppDS T i

I 5UFFLEMEhlAL REFOR1 EAFECTED (14) M0hlh DAY TEAR l

EXPECTED SUBMISSION l

] YES(If yes, complete EXPECTED SUEMISSION DATE)  % NO DATE (15) l Ab51RACI (16)

)

On 5/14/93 at 1948 CDT, Unit I was in the Hot Shutdown mode with all control rods fully inserted and reactor pressure at 75 psig. At that time, all eight Main Steam Isolation Valves (MS1Vs) closed on the unexpected receipt of a Group 1 Primary Containment Isolation System (PCIS) signal during the performance of plant surveillance procedure 34SV-E21-001-1S, "MSIV Closure ,

Instrument Functional Test." The isolation was the result of a failure to reset l partial Group 1 PCIS trips generated during the performance of the surveillance. '

No other Group 1 PCIS valves closed nor should any have closed given the logic tripped during the performance of the procedure. The MS1Vs were re-opened and the surveillance was completed successfully at 2210 CDT on 5/14/93.

The cause of this event was a less than adequate procedure. Surveillance i procedure 34SV-B21-001-1S did not state that Group 1 PCIS logic could be tripped I by the performance of the procedure nor did it require that the tripped isolation logic be reset following the testing of each MSIV closure instrument logic channel. As a result, the operator did not reset the partial Group 1 trip following the test of the "C" outboard MSIV. A full Group 1 PCIS signal was then generated when the operator began the test of the "D" outboard MSIV.  ;

Corrective actions include revising procedures 34SV-B21-001-1S and l 345V-B21-001-2S, "MSIV Closure Instrument Functional Test." i

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LICENSEE EVENT REPORT (LER)  :

TEXT CONTINUATION [

s FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (5) PAGE (3)  !

YEAR ELQ NUM REV ,

PIRIT HAIG UNIT 1 05000321 93 010 00 2 0F 4 IEAT PLANT AND SYSTEM IDENTIFICATIOT i General Electric - Boiling Water Reactor f Energy Industry Identification System codes are identified in the text as (E1IS Code XX).

DESCRIPTION OF EVENT On 5/14/93 at 1948 CDT, Unit 1 was in the Hot Shutdown mode with all control' f rods fully inserted and reactor pressure at 75 psig. At that time, all eight.

Main Steam Isolation Valves (MSIVs, EIIS Code JM) closed on the unexpected receipt of a Group 1 Primary Containment Isolation System (PCIS, EIIS Code JM) ,

signal during the performance of plant surveillanca procedure 34SV-B21-001-1S, "MSIv ilosure Instrument Functional Test." This procedure provides instructions  ;

to tec; that portion of the logic in the Reactor Protection System (EIIS Code '

JC) whLch initiates a scram signal when the MSIVs are less thaa 90% open. This  :

test is performa .at. least once every 92 days as required by Unit 1 Technical Specifications Table 4.1-1, item 10.

When the reactor mode switch is not in the Run position, as was the case when l the performance of procedure 345V-B21-001-1S began at 1700 CDT on 5/14/93, the ,

Reactor Protection System scram signal on MSIVs less than 90% open is f automatically bypassed. Similarly, the Group 1 PCIS isolation signal on low I main condenser (EIIS Code SQ) vacuum also is automatically bypassed. These two l logic system bypass signals are provided by the same set of four relays, one for each of the four Reactor Protection System and PCIS logic channels. These four  :

relays sense mode switch position and are energized when the mode switch is not in the Run position; when the relays are energized, the Reactor Protection i System scram signal on MSIVs less than 90% open and the Group 1 PCIS isolation l signal on low main condenser vacuum are bypassed.  ;

i Procedure 345V-B21-001-1S contains instructions to defeat the bypass in each of  !

the Reactor Protection System logic channels by de-energizing the relay which j provides the bypass signal for that channel. This allows the Reactor Protection  !

System scram signal in that channel to be functionally tested as required by the  ;

Unit 1 Technical Specifications when the mode switch is not in the Run position.

However, de-energizing the relay also enables the Group 1 PCIS isolation signal on low condenser vacuum in the corresponding Group 1 PCIS logic channel.

I When each relay which provides the Reactor Protection System and Group 1 PCIS  ;

bypass signals was de-energized as required by the procedure, the corresponding '

channel in the Group 1 PCIS logic tripped on low main condenser vacuum per  ;

design (the main condenser vacuum breakers had been opened at 0550 CDT on I 5/14/93; therefore, there was no vacuum in the main condenser). Additionally, annunciators illuminated indicating a Group 1 System "A" or "B" trip, as appropriate, had occurred. The PCIS trips sealed-in as designed; therefore, the isolation logic did not automatically reset as the relay was re-energized following completion of Reactor Protection System testing in that channel.

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u.s. uum eumuum wms3a g g g om LICENSEE EVENT REPORT-(LER)

TEXT CONTINUATION FACILIT1f NAME (1) DOCKET NUMBER (2) LER NUMBER (5) PAGE (3)

YEAR SEQ hum REV PUNI HATCH, UNIT 1 05000321 93 010 00 3 0F 4 TEXT The procedure required that the Reactor Protection System logic be reset prior to testing the next channel (trips in this system also seal-in per design), but it did not require that the Group 1 PCIS logic be reset. The licensed operator performing the procedure reset the Reactor Protection System logic as required.

Even though the PCIS reset is not listed in the procedures, he also reset the

.l partial Group 1 PCIS logic trips, generated during the testing of the "A" and "B" outboard MSIVs, in response to the Group 1 System "A" and "B" trip t annunciators received during the performance of the test. However, he failed to  ;

reset the Group 1 PCIS trip generated in trip system "B" when he tested the "C"  ;

outboard MSIV. Consequently, a full Group 1 PCIS isolation signal was generated at 1948 CDT when he began the test of the "D" outboard'MSIV'thereby generating a j trip in sufficient PCIS logic channels (i.e. , trip system "A" in conjunction with the existing trip in trip system "B") to isolate the_eight MSIVs. Because of the order in which the logic channels were tested, only the MSIVs received a Group 1 PCIS isolation signal. No other Group 1 PCIS valves isolated nor should  !

tb- have isolated.  !

i When it was determined that the isolation was the result of the performance of l the surveillance procedure and that the Group 1 PCIS logic functioned properly, I the MSIVs were re-opened. The surveillance was completed at 2210 CDT on 5/14/93 ,

with no further probluns.  !

CAUSE OF THE EVENT I

The cause of this event was a less than adequate procedure. Surveillance procedure 345V-521-001-1S did not state that Group 1 PCIS' logic could be tripped by the performance of the procedure nor did it require that the tripped isolation logic be reset following the testing of each MSIV closure instrument logic channel.

l REPORTABILITY ANALYSIS AND SAFETY ASSESSMENT

]

This report is required by 10 CFR 50.73(a)(2)(iv) because an unplanned actuation of an Engineered Safety Feature (ESF) system occurred. Specifically, several Group 1 PCIS valves unexpectedly closed during the performance of a surveillance procedure. These valves are components in an ESF system, namely the Primary 1 Containment Isolation System. '

The Primary Containment Isolation System provides timely protection against the onset and consequences of accidents involving the release of radioactive materials from the fuel and nuclear system process barriers. To accomplish this, the PCIS initiates automatic isolation of appropriate lines which penetrate the P.imary containment whenever monitored variables such as reactor vessel water level, main steam line radiation, drywell pressure, and main condenser vacuum exceed selected operational limits. 1

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LICENSEE EVENT REPORT (LER) t TEXT CONTINUATION t

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

YEAR SEQ hum REV PIANI HATCH, UNIT 1 05000321 93 010 00 4 0F 4 I 1 EXT In this event, several Group 1 PCIS valves, specifically, the eight MSIVs,  !

unexpectedly closed during the performance of a surveillance of MSIV closure [

instruments. The MSIVs closed on an actual low main condenser vacuum signal }

when the bypass of this isolation was removed as required by the procedure. -

Because the Group 1 PCIS isolation logic was not reset after each channel was j tested, sufficient logic channels to cause the MSIVs to isolate were tripped.

The Group 1 PCIS logic system functioned as designed given the signals which ,

were generated by the performance of the surveillance procedure.

Based on the above analysis, it is concluded that this event had no adverse impact on nuclear safety. This analysis is applicable to all power levels and -

operating modes. ,

CORRECTIVE ACTIONS Procedures 34SV-B21-001-1S and 34SV-B21-001-2S, "MSIV Closure Instrument Functional Test," will be revised prior to their next scheduled performances to caution the user that performance of the procedure could affect Group 1 PCIS ,

logic and to require that this logic be reset, as necessary, following the l completion of testing in each Reactor Protection System logic channel. l

.i ADDITIONAL INFORMATION No systems other than those mentioned in this report were affected by this j event. j l

No failed components caused or resulted from this event.

One previous similar event in the last two years in which an inadequate l procedure caused an unexpected ESF system actuation was reported in Licensee Event Report 50-321/1991-031 dated 12/23/91. In that event, a Group 5 PCIS valve isolated on high Reactor Water Cleanup System (EIIS Code CE) differential flow. The high differential flow signal resulted when a Reactor Water Cleanup System pump was placed into service with the system piping partially voided due to temperature changes while the system was out of service The system ,

operating procedure did not caution against this possibility nor did it provide l sufficient instructions to avoid an isolation while returning a pump to service l under these conditions. Corrective actions included revising the Unit 1 and Unit 2 Reactor Water Cleanup System operating procedures to correct these deficiencies. Corrective actions for the previous similar event would not have prevented this event, however, because the two events involved completely different procedures and activities.