ML17261A916

LER 89-016-00:on 891220,determined That Single Failure of Safety Injection Block/Unblock Switch Could Render Some Automatic Actuation Features Inoperable.Caused by Design Deficiency.Also Reportable Per Part 21

ML17261A916
Person / Time
Site:	Ginna
Issue date:	01/12/1990
From:	Backus W ROCHESTER GAS & ELECTRIC CORP.
To:
Shared Package
ML17261A915	List: ML17261A914 ML17261A916
References
REF-PT21-90 LER-89-016, LER-89-16, NUDOCS 9001240152
Download: ML17261A916 (8)

Text

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LICENSEE CONTACT tOII THIS Ltll 115)

NAME TELtt)SONS HUIASKII Wesley H. Backus AIIEA COOS Technica' sistant to the rations Mana er 31 5524 -4446 COMt LET E ONE LINE t Oil EACH COMAONCNT tAILUAEOKSCIII~ KO IH TSSIS llctOAT llcl MANUSAC. ttOIITASLK MANUSAC. ttOATASL CAV5K SYSTEM COMtONEHT TVAEII TO HtIIOS CAUS t SYSTEM COMtONEHT TVAKII TO Htl)OS &~4~4>@w:

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On November 17, 1989, an initial Engineering evaluation was completed, which identified a potential problem with the Safety injection (SZ) Block/Unblock Switch.

On December 20, 1989, at 1630 EST, with the reactor at approxi-mately 99% full -power, the Plant Operating Review Committee (PORC) reviewed the Engineering evaluation, and made a final determination that a single failure of the SI Block/Unblock Switch could render some automatic actuation, features of both trains. of SZ inoperable. f The PORC, after reviewing the situation thoroughly, ;:oncluded that sufficient justification existed, for continued safe plant operation.

The underlying cause of the event was a - design;=error '.which occurred during the original construction of -,the R.E.. Ginna.. .

Nuclear Power Plant.

Immediate corrective action was taken to verify that the plunger position of the SX Block/Unblock Switch contacts were in 'he et" s io proper position.

NAC Sere SOS I&45I 5)0012401 2 900112 PDR 'DOCK 05000244 ee' . 1o PDC

NRC Form 844A U.S. NUCLEAR REOULATORY COMMISSION I9$ 51 LICENSEE EVENT REPORT ILER) TEXT CONTINUATION . APPROVED OMB NO. 5150&144 EXPIRES. BISI/85 FACILITY NAME (11 DOCKET NUMBER IXI LER NUMBER (El ~ AOE IS) 5EOVCNTIAL sP I REVISION NVMPER '<1; NVMPPR R.E. Ginna Nuclear Power Plant o s o o o 2 448 9 0 1 6 0 0 0 OF 0 8 TEXT iH moro spoco is rxrrerorL oso RsrOooW HRC Forrrr SBSA'sl I IT I PRE-EVENT PLANT CONDITIONS The plant was at approximately 994 steady state full power with no major activities in progress.

DESCRIPTION OF EVENT A. DATES AND APPROXIMATE TIMES FOR MAJOR OCCUREKNCES:

o Initial plant operation in 1969: Event date.

o November 17, 1989: Discovery date.

o December 20, 1989, 1630 EST: Reportability date and time.

o December 20, 1989, 1630 EST: Plant Operating Review Committee (PORC) determines that safe operation of plant may continue.

B. EVENT On November 17, 1989, an initial Engineering evaluation was completed, which identified a potential problem with the SI Block/Unblock Switch. Subsequently, PORC review of the Engineering evaluation, on December 20, 1989, with the reactor at approximately 994 full power, determined that a single failure of the Safety Injection (SI) Block/Unblock Switch could render some automatic actuation features of both trains of SI Inoperable. This determination followed. an evaluation of the following correspondences:

o Letter from S.P. Swigart of the Westinghouse Electric Corporation (NS-OPLS-OPL-I-89-517) to Mr. R. Eliasz, Rochester Gas and Electric Corporation (RG&E), dated October 12, 1989, Sub)ect: Control Room Safety Injection Block Switches.

NRC FORM 554A 1945 I

NRC Form 344A U$ . NUCLEAR REOULATORY COMMISSION

(&43l LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVEO OMS NO. 3150&10(

EXPIRES. Sfll/85 FACILITY NAME (11 OOCKET NUMSER (ll LER NUMSER IS) PACE (3I "EA" AN SEOVENTIAL oiy. IIEVOION NVM ER :AA NVM 81 R.E. Ginna Nuclear Power Plant o s o o o 244 8 9 016 0 0 3 DF0 8 TEXT N moro oPoco r'o rorRrood, uw dduoonro( HRC %%dnrr 383A1I (ITI o Interoffice Correspondence from Richard Baker to P. Wilkens and G. Wrobel, dated November 17, 1989, Sub)ect: Control Room Safety Injection Block Switches.

The Westinghouse Correspondence (NS-OPLS-OPL-I 517) identified a potential single failure mechanism which could result in blocking of some automatic actuation features of both trains of SI, (i.e. SI automatic actuation from low pressurizer pressure and low steam line pressure). Specifically, a single manual switch on the Main Control Board (MCB) is used to control this SI Block/Unblock function for both SI trains. An Engineering Evaluation of the existing Ginna Station SI Block/Unblock wiring configurations has concluded that, the Westinghouse described potential single failure mechanism is applicable to Ginna Station. The Engineering Evaluation also concurred with the Westinghouse position that due to the low probability of a switch failure sufficient )ustifica-tion exists for continued plant operation until separate A train and B train SI Block/Unblock Switches can be installed.

The PORC after reviewing the above correspondence concluded that sufficient Justification exists for continued safe operation of the plant.

C ~ INOPERABLE STRUCTURES, COMPONENTS, OR SYSTEMS THAT CONTRIBUTED TO THE EVENT:

None.

D. OTHER SYSTEMS OR SECONDARY FUNCTIONS AFFECTED:

None.

NRC FORM 344A 18431

NRC Form BASSA U.S. NUCLEAR REOULATORY COMMISSION 1943)

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVEO OMS NO, 3)50&104 EXPIRES) 8/31/85 FACILITY NAME I 1) DOCKET NUMSER IS)

LER NUMBER 14) PACE IS)

VEA4 '4 QrK SEQUENTIAL NVM 44 889

~>i8 4EVISION NVM 44 R.E. G'nna Nuclear Power Plant o 5 o o o" 44 8 9 016 0 0 0 4 OF TEXT /// moro o/rooo 4 44/vomE Iroo ///ooro///RC For//I JSSA'el I)7)

E. METHOD OF DISCOVERY:

The event was made apparent due to Engineering's review of the following correspondence:

o, Letter from S.P. Swigart of the Westinghouse Electric Corporation (NS-OPLS-OPL-I-89-517), to Mr. R. Eliasz, RG&E, dated October 12, 1989,

Subject:

Control. Room Safety In)ection Block Switches.

o This was documented in Interoffice Correspondence from Richard Baker to P. Wilkens and G. Wrobel, dated November 17, 1989, Sub)ect: Control Room Safety Injection Block Switches.

o The event was determined to be reportable following PORC review of the previous correspon-dence.

F. OPERATOR ACTION:

As this was a design deficiency, with only the potential for component failure, no immediate operator action was necessary.

G. SAFETY SYSTEM RESPONSES:

None required.

U OP The underlying cause of the event is a design error which occurred during the original construction of th;E.

Ginna Nuclear Power Plant.

NRC FORM SSSA

)943)

NRC Fons 3SSA U.S. NUCLEAR REOULATORY COMMISSION (943)

LICENSEE EVENT REPORT (LERI TEXT CONTINUATION APPROV EO OMS NO, 3150M(04 EXPIRES. 8/31/SS FACILITY NAME (II OOCKET NUMSER (2) LER NUMBER (SI PACE (3I VEAR .~j: SSOVSNTIAL hSVISION NUMeth R.E. Ginna Nuclear Power Plant o 5 o o o 2 4 4 8 9 0 j.6 0 0 0 5 OF 0 8 TExT ///more toeot /I reovethE e>> /A/o'st////Ic %%drrrr 30%4't/ l)TI IV. ANALYSIS OF EVENT This event is reportable in accordance with 10 CFR 50.73, Licensee Event Report System, items (a)(2)(v)(D) and (a)(2)(vi) which requires a report of, "any event or condition that alone could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident", and 10 CFR 21, "Reporting of Defects and Noncompliances". The "basic component" is the SZ Block/Unblock Switch, supplied by Westinghouse Electric Corporation as part of the original Ginna Station design. The potential failure of the SI Block/Unblock Switch rendering the automatic actuation of SI from low pressurizer pressure and low steamline pressure inoperable is considered a condition that alone could have prevented the immediate fulfillment of a safety function needed to mitigate the consequences of an accident.

An assessment was performed considering both the safety consequences and implications of this event with the following results and conclusions:

PORC determined there were no immediate operational or adverse safety consequences due to the potential failure of the SZ Block/Unblock Switch because:

0 Westinghouse has stated that the probability of a SI Block/Unblock Switch failure is very low (approximately 10 to 10 /yr) .

o Immediate action step 4 (performed from memory) of Emergency Operating Procedure E-O, Reactor Trip or Safety Zn) ection, directs the operator to check parameters for SZ actuation rather than rely on automatic actuation features. Manual actuation of SI and containment isolation is required fall below the auto SZ actuation setpoints.

if parameters NRC FORM 3SSA 1943)

NRC Ferrtr 3ddA V.S. NUCLEAR REOULATORY COMMISSION

)883) t LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVED OMS NO, 3150M)04 EXPIRES,'/31/85 FACILITY NAME (I) DOCKET NUMbER (31 PACE (31 LER NUMSER Idl YEAII SSOVSNTIAL II@ V IS IO N

??.o NVM SN NVM SN R.E. Ginna Nuclear Power Plant p t?pp ps 4 4 89 016 0 006 OF 0 8 TEXT /// more douce it /equeed, ute I/IRuuM/HRC Fer?II ~'t/ I)7) o Containment pressure of 4 psig will automatically actuate SI independent of the SI Block/Unblock Switch configuration. SI on HI Containment Pressure is used as a backup to the low pressurizer pressure and low steamline pressure SI actuation.

o If the SI signal is blocked during depressurization, a bistable light. will alert the operator of the blocked status.

o Initial inspection of the plunger position of the SI Block/Unblock Switch verified that the switch contacts were (and continue to be) in the proper position.

Based on the above, it can be concluded that the public's health and safety will be assured at all times. Due to the date of occurrence, the condition is technically not 10 CFR 21 reportable. However, due to the potential significance of the failure scenario, Rochester Gas and Electric is submitting voluntary notification.

V. CORRECTIVE ACTION A. ACTION TAKEN AS A RESULT OF THE EVENT:

0 Knowledgeable personnel inspected the plunger position of the SI Block/Unblock Switch and "

verified that the switch contacts were in the proper position.

0 Operating Procedure 0-1.1 (Plant Heatup From Cold Shutdown to Hot Shutdown) "was changed to add the following note and chyck-off to step F 11.6: I NIIC FOIIM SSSA IS431

NRC FOIRI 344A U.S. NUCLEAR REOULATORY (:OMMISSION (P43)

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVEO OMS NO, 3150&1(N EXPIRES: 813(185 FACILI'TY NAME (11 OOCKET NUMSER (ll LER NUMSER (5) PACE I31 YEAR: M 55QVENTIAL NVMSER

+ REVISION

",X'VM ER R.E. Ginna Nuclear PGwer P3.ant: o s o o o 24 489 01 6 00 07 OF TEXT Il(mom NMce N IeqviNS u>> ddcoonsl lyRC FomI 3(5(AS( (ITI NOTE: Prior to placing the SZ Block/Unblock Switch to the normal position, station an operator inside the MCB in direct observation of the SZ Block/Unblock Switch, to observe that both plunger tips are recessed inward after the switch is placed to normal position.

Block switch plunger tips position inward o An RG&E operator aid tag was placed on the MCB ad)acent to the SZ Block/Unblock Switch denoting the note from O-l.l.

o An RG&E operator aid tag was also placed inside the MCB adjacent to the rear of the SZ Block/Un-block Switch stating the following: This is the switch we verify that the plunger's tips are recessed inward when the switch is placed to normal (labeled LAK).

o A spare switch of similar design has been placed in the Control Room for the purpose of training the operators to recognize the differences in plunger position.

B. ACTZON TAKEN OR PLANNED TO PREVENT RECURRENCE:

0 During the 1991 Refueling Outage, subject to equipment availability, a design change and modification will be made-,to:, separate the Block Switches for each SZ train".

0 A review of the application of:similar switches will be performed, to determine sric implications.

if there are 0 Due to the delay between "discovery -.date" ...and "reportability date", improvements will 'be 'made in the RG&E internal review process, including means for formal notification of Ginna Station of potentially reportable.

issues.'RC FORM 355A (5431

NRC form 3$ 4A U.S. NUCLEAR REOULATORY COMMISSION (NI3)

LICENSEE EVENT REPORT (LERI TEXT CONTINUATION APPROVEO OMS NO. 319)&(OS EXPIRES; 8/31/8$

FACILITY NAME (I I OOCKET NUMBER l2) LER NUMSER (8) PACE ISI YEA/I SSOUCNTIAL IIS V IS IO N NUM S II NUM SA R.E. Ginna NUclear Power -Plant o 5 o o o 2 489 0 1 6 0 008 OF 0 8 TEXT /I/ moro s/>>so /s or)UsOIE oso sASSO'cv>>/ H//C forrrr 3/E(A'/ Ill) o Westinghouse will be notified of this isolated occurrence, in which Ginna Station was not notified by Westinghouse.

VI .. ADDITIONAL INFORMATION A. FAILED COMPONENTS':

None identified.

B. PREVIOUS LERs ON SIMILAR EVENTS:

A similar LER event historical search was conducted with the following results: No documentation of similar LER events with the same root cause at Ginna Station could be identified.

C. SPECIAL COMMENTS:

None.

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NIIC FORM 344A (943)