ML18052B226

LER 87-023-00:on 870712 & 0621,inadvertent Actuation of Diesel Generators Occurred When Latching Turbine Generator. Caused by Personnel Error.Procedures Changed & Operations Personnel Notified as to Cause of event.W/870811 Ltr

ML18052B226
Person / Time
Site:	Palisades
Issue date:	08/11/1987
From:	Johnson B, Lewis J CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
LER-87-023, LER-87-23, NUDOCS 8708170161
Download: ML18052B226 (4)

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• l - l r fl- b NO llflf/**IPK* tr1>>written /inal 1111 IUIMllllON DATE 1151 I I I On July 12, 1987 at 0346, die~el generators 1-1 and 1-2 [EK;DG] inadver-tently actuated while Operations personnel were latching the turbine generator [SB;TG] during performance of a Reactor Protection System (RPS) [JC] checklist. The Plant was in hot shutdown condition (primary coolant system: 2011 psia, 528 degrees F) at the time of the event.

Electric/hydraulic circuit timing during the latching process creates a situation which can result in inadvertent diesel generator start if not carefully prevented.

On June 21, 1987, a similar event occurred which resulted in the inad-vertent actuation of the diesel generator when latching the turbine generator. The corrective actions for this event included procedure changes and notification of Operations personnel as to the cause of the event. Procedural changes were completed prior to the assigned due date, however, all Operations personnel had not been notified.

The failure to notify all operators in a timely manner resulted because the Operations Superintendent and Plant Corrective Action Review Board Chairman approved a 30 day completion date, assuming the Plant would not be shutdown during the action completion time. Procedural changes have been completed, and Operations personnel notified of these changes and their significance.

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18-831 LER 87-023-NL02

NRC form 3HA *. NUCLEAR REGULATORY COMMISSION 19-831 LICENSEE EVENT REPORT (LERI TEXT CONTINUATION APPROVED OMB NO. 3150~104 EXPIRES: 8/31 /85 FACILITY NAME Ill DOCKET NUMBER 121 LER NUMBER (Ill PAGE 131 VEAR ;:;:;:;:;:SEQUENTIAL ;:;:;:;:::* "EVISION

NUMBER  :::::::::: NUMBER PALISADES NUCLEAR PLANT 0 1s I 0 I 0 I 0 12 15 I 5 81 7 - 012 I 3 - 0 I 0 0 12 OF 0I3 TEXT l/f,,,,,,. - ia fW/uftd, u* MJditioMI NRC Fann 31115A'*I 1171 Description On July 12, 1987 at 0346, diesel generators 1-1 and 1-2 [EK;DG] inad-vertently actuated while Operations personnel were latching the turbine generator [SB;TG] during performance of a Reactor Protection System (RPS) [JC] checklist. The Plant was in hot shutdown condition (primary coolant system: 2011 psia, 528 degrees F) at the time of the event.

In preparation for returning the Plant to service, Operations personnel were performing Checklist 36; "Reactor Protective System Checklist, Breakers and Cables". During performance of this checklist, operators are directed to latch the turbine generator and then verify that turbine trip output functions would receive an actuation signal. As the turbine generator was.latched, and prior to any further operator action with regard to Checklist 36, diesel generators 1-1 and 1-2 actuated.

Investigations into the cause of the event revealed that operators on-shift did not hold the diesel generator control switch in the stop position when latching the turbine generator. Direction to perform this action was added to Standard Operating Procedure (SOP) 8; "Main Turbine and Generating Systems" on July 10, 1987. This action and additional precautionary statements were added to SOP 8 in response to the June 21, 1987 inadvertent diesel generator actuation. Information regarding the June 21, 1987 actuation can be found in Palisades Licensee Event Report 87-019, "Failure of Autostop Oil Pressure Switch Results in Inadvertent Diesel Generator Actuation".

The diesel generators were subsequently secured and Checklist 36 comp-leted at 0417.

Cause Of The Event The failure of on-shift Operations personnel to be aware of the preceeding event has been attributed to corrective action due date assignment the Operations Superintendent and the Plant Corrective Action Review Board (PCARB) Chairman. On June 21, 1987, diesel generators 1-1 and 1-2 inadvertently actuated while operators attempted to latch the turbine generator. Investigations revealed that the inherent design of the turbine.autostop oil pressure system and associated mercoid pressure switches 63 AST/1&2 [TD;PS] could yield turbine trip and consequent diesel generator actuation signals. Corrective actions taken to preclude subsequent diesel generator actuations included the revision of SOP 8. This revision instructed Control Room operators to hold the diesel generator control switch in the stop position for 45 seconds when latching the turbine generator. This practice has been inconsistently performed in the past without procedural guidance, it was not performed during the June 21, 1987 turbine latching. Additionally, a precau-tionary statement was added to alert operators of the possibility of NRC FORM 366.A 19-831 LER 87-023-NL02

'lllRC Form 3611A .S. NUCLEAR REGULATORY COMMISSION 19-831 LICENSEE EVENT REPORT (LERI TEXT CONTINUATION APPROVED OMB NO. 3150--0104 EXPIRES: 8/31185 FACILITY NAME (11 DOCKET NUMBER (21 LER NUMBER 161 PAGE (31 PALISADES NUCLEAR PLANT 0 15 I 0 I 0 I 0 I 2 I 5 15 817 - 012 I3 - 0 I0 013 OF 0 I3 TEXT (If mtn .,,.co ii fW/uftd, u* IMklmon.1 NRC Fonn 31115A 'al 1171 diesel generator actuations due to vibration within mercoid pressure switches. This action was completed July 10, 1987 (prior to the assigned July 24, 1987 completion date), however, all Operations per-sonnel on-shift had not been made aware of the procedural changes. This action was also to be completed by July 24, 1987.

When this date was assigned by PCARB, it.was assumed the Plant would not be shutdown during the period when the actions were to be completed and that the diesel generators would not be subject to inadvertent actuation.

Corrective Actions This item is considered to be an isolated incident as other similar situations have been controlled and appropriate actions implemented without event by the individuals involved.

As stated, SOP 8 has been revised to include precautionary statements and operator guidance regarding the potential for diesel generator actuation when latching the turbine. All shifts of Operations personnel have been made aware of the event and procedure changes made.

System Engineering personnel are evaluating the necessity for system moaifications. This evaluation is to entail a review of actuation logic and the feasibility of utilizing a different style pressure switch ie, without mercury as the conducting mechanism. Included in this review of switch design will be the elimination of bouncing and circuit continuity loss if a switch design utilizing a conducting mechanism other than mercury is utilized.

Analysis Of The Event In that the reactor was in hot standby condition at the time of the event and the deenergizing of autostop oil pressure switches 63 AST/1&2 results in a turbine trip and diesel generator actuation signal, no safety hazard existed.

Also, as the bouncing effect seen in the mercoid pressure switch is believed to only occur during the rapid autostop oil pressure increase when the turbine is latched, no additional safety consequences are believed to exist.

This event is being reported per 10CFRS0.73 (a)(2)(iv) as a condition which resulted in the automatic actuation of an Engineered Safety Feature.

Additional Information For information regarding inadvertent diesel generator actuation when latching the turbine generator, reference Licensee Event Report 87-019.

NRC FOAM 366A 19 831

' LER 87-023-NL02

, POWERIN&

MICHl&AN'S PRO&RESS General Offices: 1945 West Parnall Road, Jackson, Ml 49201 * (517) 788-0550 August 11, 1987 Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT -

LICENSEE EVENT REPORT 87-023 - UNTIMELY COMMUNICATION RESULTS IN INADVERTENT DIESEL GENERATOR ACTUATION Licensee Event Report (LER)87-023, (Untimely Communication Results in Inadvertent Diesel Generator Actuation) is attached. This event is reportable to the NRC per 10CFR50.73(a)(2)(iv).

Brian D Johnson Staff Licensing Engineer CC Administrator, Region III, USNRC NRC Resident Inspector - Palisades Attachment OC0787-0116-NL02