ML20041F541

LER 82-009/03L-0:on 820208,differential Pressure Transmitter PDT-5000 Failed High,Rendering Emergency Ventilation Sys Train 1-1 Inoperable.Caused by Ice Buildup on Vent Line Outside Auxiliary Bldg.Ice Removed

ML20041F541
Person / Time
Site:	Davis Besse
Issue date:	03/09/1982
From:	Isley T TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20041F533	List: ML20041F532 ML20041F541
References
LER-82-008-03L, LER-82-8-3L, NUDOCS 8203170119
Download: ML20041F541 (2)

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LICENSEE EVENT REPORT 90 TROL BLOCK: l

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(PLEASE PRINT OR TYPE ALL REQUIRED INF8RMATION) le l i 8l 910'l H l D l B l S 14l 1 l@l 15 0 l0 l- 10LICENSE 10 l0 10 l0 l- 10 10 NyVSER 25 l@l 26 4 l 11 il TYPE LICENSE 1l 1l@l Jo l

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EVENT DESCRIPTION AND PROB ABLE CONSEQUENCES h l o 121 l (NP-33-82-09) On February 8, 1982 at 1210 hours0.014 days <br />0.336 hours <br />0.002 weeks <br />4.60405e-4 months <br />, a control room operator observed thatI g a ;3 i lPDl-5000 had failed high. With transmitter PDT-5000 failed, Emergency Ventilation l 1/4 inch negative pressure in thel Io la l I System (EVS) Train 1-1 would not be able to draw a

[o;3gjannulus. EVS Train 1-1 was declared inoperable and the station entered the action I loleI lstatement of Technical Specification 3.6.5.1. There was no danger to the health and i l o l 7 l l safety of the public or station personnel. EVS Train 1-2 was operable and capable of I l o Ia l Imaintaining the required negative pressure. l 80 7 8 9 E CODE SUBC E COMPONENT CODE SUSC OE S E lol91 lS lH l@ ]@ l Xl@ lI j N l S lT lR lU l@ {@ J @

13 18 19 20 7 8 9 10 11 12 OCCURRENCE REPORT REVISION

,,,, SEQUENTI AL EVENT YEAR REPORT No. CODE TYPE NO.

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_ 22 23 24 26 27 28 29 30 AK ? A O ON PL NT MET HOURS 22 SB IT FC B. SUPPLIE MANUFACTURER IX J3 lgl34Z lg l35Z lg l36Zl@ 31 l0l0l0l 40 l gg 43 lN lg l3Z lg l Z l 9 l 9 l 9 lg 42 4 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS h l i l o l l The cause was an ice buildup on the transmitter vent line outside of the Aux 111arv l l,l3; l Building. Apparently the unusual weather had caused the buildup. With the line I

,,,,,l plugged, PDI-5000 was not indicating the true differential pressure between the annu-l g l lus and the outside atmosphere. Under MWO IC-146-82, the ice was removed from the j g l line. At 1400 hours0.0162 days <br />0.389 hours <br />0.00231 weeks <br />5.327e-4 months <br /> on February 9, 1982, EVS Train 1-1 was declared operable. 80 l

7 8 9 STA S  % POWER OTHER STATUS ISCO RY DISCOVERY OESCRIPTION iTTTl l El@ l 0 l 6 l 9"l@l"NA l l A l@l Operator Observation l ACTIVITY CO'N T E NT AYOUNT OF ACTIVITY LOCATION OF RELEASE RELE ASED OF RELEASE R W8 9@ l Z l@l NA l l NA l 44 45 80 I 7 to 11 PERSONNEL EXPOSURES NUVBER

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• 8203170119 820309 PUstiETY NRC USE ONLY PDR ADOCK 05000346 ,

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om Isley 419-259-5000, Ext. 230 2 BVR 82-019 NAME OF PREPARER - PHONE:

. .. . TOLEDO EDISON COMPANY DAVIS-BESSE NUCLEAR POWER STATION UNIT ONE SUPPLEMENTAL INFORMATION FOR LER NP-33-82-09 DATE OF EVENT: February 8, 1982 FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Mechanical Penetration Room 4 Pressure Gauge PDI-5000 failed high Conditions Prior to Occurrence: The unit was in Mode 1 with Power (MWT) = 1911.6 and Load (Gross MWE) = 611.

Description of Occurrence: On February 8, 1982 at 1210 hours0.014 days <br />0.336 hours <br />0.002 weeks <br />4.60405e-4 months <br />, the control room operator observed PDI-5000 had failed high indicating a failure of PDT-5000. The differential pressure transmitter feeds a controller which regulates dampers which allow recirculation of Emergency Ventilation System (EVS) exhaust back to contain-ment. This allows the differential pressure to be maintained at a nominal 3/4" w.g. and permit mixing of containment vessel leakage with purified air. This pre-vents direct streaming of radioisotopes to the filter system by increasing holdup within the annulus. With PDI-5000 failed high, EVS Train 1-1 would not maintain 0.25 inches w.g. negative pressure in the containment annulus because full recircu-lation would be demanded. EVS Train 1-1 was declared inoperable placing the unit in the action statement of Technical Specification 3.6.5.1.

Designation of Apparent Cause of Occurrence: The indicator failed high because of ice buildup on the transmitter vent line outside of the Auxiliary Building. The ice plugged the vent line causing the indicator to fail high.

Analysis of Occurrence: There was no danger to the health and safety of the public or station personnel. EVS Train 1-2 was operable and capable of maintaining the required negative pressure.

Corrective Action: The Instrument and Control mechanics remor. 'he ice from the vent line and returned the transmitter to service under Maintes a.. Work Order IC-146-82. EVS Train 1-1 was declared operable at 1400 hours0.0162 days <br />0.389 hours <br />0.00231 weeks <br />5.327e-4 months <br /> on Tebruary 9, 1982, l removing the station from the action statement. It is presently being investigated whether a cost effective facility change can be designed to prevent recurrence.

Failure Data: None previously reported due to ice buildup.

l LER #82-008

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