05000285/LER-1976-021, Suppl 1 to LER 76-21/03L:on 760802,timer Relays for SI-3A, AC-3B & SI-3B Failed to Time Out at Set Times.Caused by Binding Operating Mechanisms.Timers Tested Twice Weekly to Verify Operability Until Replacements Received

Suppl 1 to LER 76-21/03L:on 760802,timer Relays for SI-3A, AC-3B & SI-3B Failed to Time Out at Set Times.Caused by Binding Operating Mechanisms.Timers Tested Twice Weekly to Verify Operability Until Replacements Received

ML20087K028
Person / Time
Site:	Fort Calhoun
Issue date:	08/09/1976
From:	Connolley J, William Jones, Nagl J OMAHA PUBLIC POWER DISTRICT
To:	Howard E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
Shared Package
ML20087K031	List: 05000285/LER-1976-021, Suppl 1 to LER 76-21/03L:on 760802,timer Relays for SI-3A, AC-3B & SI-3B Failed to Time Out at Set Times.Caused by Binding Operating Mechanisms.Timers Tested Twice Weekly to Verify Operability Until Replacements Received
References
FC-242-76, LER-76-21-03L, LER-76-21-3L, NUDOCS 8403230221
Download: ML20087K028 (6)

LER-2076-021, Suppl 1 to LER 76-21/03L:on 760802,timer Relays for SI-3A, AC-3B & SI-3B Failed to Time Out at Set Times.Caused by Binding Operating Mechanisms.Timers Tested Twice Weekly to Verify Operability Until Replacements Received

Event date:
Report date:
2852076021R00 - NRC Website

text

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. LICENSEE EVENT REPORT En 50-285/76-21 (Suppicment) ,

1 CONTROL OLOCK:l l l l l l l [PLEASE PRINT ALL REQUIRED INFORMATION) 1 o  !

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7 89 l NI El ric 1811l 14 1S 31 32

" EVENT DAM REPDHT DATE CAllCOHY 5 DOCKLT NUM014

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@ CON'T l ' l 61 00 Go 74 75 00 7 u 57 du 60 EVE'NT DESCn:PTION

. @ lDuring the twice weekly testing of Sequencer timer relnys the monthly Sennencer sur- 00l 7 u9

__i@ lv~e111ance Test ST-ESF-5 was performed. Timer relays for SI-3A. AC-3B and SI-3B failed l l

-7 09

, @ lto time out at their set times. (LER 50-285/76-21 Supplement No. 1) l i UU 7 oo -

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CODE COMPONENT CODE W

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@ l Sl Fl @ l Cl K] Tl El K l R l l Al lE' l0 l2 l0 l  ;

7 89 10 11 12 17 43 44 47 40 CAUSE DESCRIPTION 1

@ lThe Blisa Eagle timer relays had binding operating mechanisms which retarded the UU 7 ao

@ l timer relays after they' had received their initiating signal . The timers are beine 80 7 89 l

@ l tested on a twice weekly basis to verify their operability.

OTHER STATUS 1 COVERY DISCOVERY DESCAPTON

'^[AIU S  % POWER Q

7 0

~lEj 0

l 1l 0l 0l l NA 10 12 13 l

44 d45 l 46 NA 80 l

AMOUNT OF ACTNtTY LOCATON OF RELEASE i EAS OF l

7 0 0 b [_ZjEASENA 10 11 l l 44 l

45 NA 80 PERSONNEL EXPOSURES NUM0E R TYPE DESCR@ ION l

@ l0 l0 l 0 11l 7 09 Wl 12 13 NA 80 PERSONNEL INJURIES NUMDER DESCHiPTON h l0l0l0l11 12l NA

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OFFSITE CONSEQUENCES' l

{IS l NA - - 80 7 09 LOSS OR OAMAGE TO FACILITY T YF'E DESCROTON ~

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! 7 89 10 l NA 00 PUBLtCITY 0

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ADOITIONAL FACTORS l

g gg l See Attachmenta No.1, 2 and 3. B0 l 7 8D I

DE I 80 7 89 NAME: J. M. Nag 1/J. L. Connn11oy PHONE: 402-426 h011

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O O LER 50-285/7(2-21 (Suppleme,nt No. 1)

Page Two . ,

. ATTACHMENT NO. 1 Safety Analysis The plant electrical system is so designed that no single. failure can jeopardize enough engineered safeguard equipment to prevent the safe shut-down of th.c plant. The failure of timer relays' for CH-1A, SI-3A, AC-3B and SI-3B vould not have prevented the complete and proper sequential loading of the above equipment had it been required.

Prior to starting ST-ESF-5, prime signal sequencers S1-1 and 32-1 were operable and in auto standby. The derived signal sequencers Sl-2 and S2-2 were then separately bypassed as per ST-ESF-5 to test their " Bliss Eagle" timing relays. In the event the derived signal sequencers (Sl-2 and S2-2) ,

had been called upon to load the above equipment during the performance of ,

ST-ESF-5, the respective prime signal sequencers (Sl-1 and S2-1) would have loaded CH-1A, SI-3A, AC-3B and SI-3B at their prescribed times.

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e NITACID4ENT NO. 2

, Corrective Action The timer relays for the derived signal sequencers S1-2 and S2-2 are being tested twice wealdy since the initial timer failures of June 29, 1976. During this twice veckly testing it has frequently been necessary to perform the timer test twice to verify the operability of the timers.

(See Attachment No. 3 for Failure Data during twice veckly testing.)

One additional timer fai]ure has been noted during this testing; Sequencer 81-2 timer relay for SI-1A has failed to time out at its set time of 14.0 seconds.

These failed relays vill continue to be tested on a twice veckly '.

basis until the replacement timers are received from the Bliss Eagle 1 Signal Company at which time they will be installed and tested.

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LER 50-285/'(6-21 (Supplement No. 1)

Page l'our -

- ATTAC]iMENT Ho. 3 Failure Datn This is the fourth event involving the failure of Bliss Eagle Signal timing relays. See Abnormal Occurrence Reports 50-285/75-1, 75-13 and 75-16.

F See the attached failure data from twice weekly testing July 12 - August 6, [

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.Q_T Omaha Public Power District ...-

1623 HARNEY a OMAHA. NEllRASKA 68102 m - TELEPHONE 036-4000 AREA CODE 402 August 10, 1976 FC-2h2-76 f 5 Mr. E. Morris Howard

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A['$LlJ[f 9 (UL f ;f}XdE.gf U. S. Nuclear Regulatory Commission [ s Region IV 611 Ryan Plaza Drive Suite 1000 Arlington, TX 76012

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Dear Mr. Howard:

Q@ 7gyjjf;j'h Vat pe n '%,

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Reference:

Fort Calhoun Station Unit No.1 -

Docket No. 50-285 In accordance with the Fort Calhoun Station's Technical Specifica-tions, the Omaha Public Power District, as holder of facility operating license DPR-40, submits three copies of the following supplement to licensee event report 50-285/76-21 to satisfy the requirements of Regula~

tory Guide 1.16.

Sincerely, f/dV W. C. fones Sectio Manager Operations WCJ/WDD:rge Enclosure cc: Director, Office of Management Information and Program Control U. S. Nuclear Regulatory Commission Washington, DC _ 20555 (3)

Director, Office of Inspection and Enforcement U. S. Nuclear Regulatory Commission Washington, DC 20555 (30)

Mr. L. C. Shalla .. \,

SARC Chairman PRC Chairman Fort Calhoun File (2) V 8415; -

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