05000321/LER-1981-051-03, /03L-0:810607,turbine Failed to Trip at Less than or Equal to 5,000 Rpm During Testing.Caused by Broken Turbine Trip Ball,Scored Trip Piston & Out of Calibr Diaphragm Oil Control Valve.Ball Replaced & Valve Cleaned

/03L-0:810607,turbine Failed to Trip at Less than or Equal to 5,000 Rpm During Testing.Caused by Broken Turbine Trip Ball,Scored Trip Piston & Out of Calibr Diaphragm Oil Control Valve.Ball Replaced & Valve Cleaned

ML20005A053
Person / Time
Site:	Hatch
Issue date:	06/23/1981
From:	Coggin C GEORGIA POWER CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20005A046	List: 05000321/LER-1981-051, Forwards LER 81-051/03L-0 05000321/LER-1981-051-03, /03L-0:810607,turbine Failed to Trip at Less than or Equal to 5,000 Rpm During Testing.Caused by Broken Turbine Trip Ball,Scored Trip Piston & Out of Calibr Diaphragm Oil Control Valve.Ball Replaced & Valve Cleaned
References
LER-81-051-03L, LER-81-51-3L, NUDOCS 8106290303
Download: ML20005A053 (2)

LER-1981-051, /03L-0:810607,turbine Failed to Trip at Less than or Equal to 5,000 Rpm During Testing.Caused by Broken Turbine Trip Ball,Scored Trip Piston & Out of Calibr Diaphragm Oil Control Valve.Ball Replaced & Valve Cleaned

Event date:
Report date:
3211981051R03 - NRC Website

text

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8 EVENT DESCRIPTION AND PROB ABi.E CONSEQUENCES h o 2 lWith Unit 1 in the startup mode and Rx pressure at 150 lbs, 4!. thermal I

test being performed, the; g,g,, power and the HPCI turbine mech overspeed trip lo til l turbine f ailed to trip ct less than or equal to 5000 RPM.

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lo 131 I reportable under Tech Specs 6.9.1.9.B.

As per Tech Specs 3.5.D.2 RCIC. I IADS, CSS, and LPCI were operable, and no significant events occurred.

I o o o 7 IThis is a repetitive event; ref. LER #50-321/1980-088.

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JJ 34 35 36 34 43 41 42 43 44 47 CAUSE DESCnlPTION AND CORRECTIVE ACTIONS h 1:101IThe event was due to a broken turb. trio ball. a scored trip piston, andi lilillan out of calibration diaohranm oil control valve.

The ball was re-lplaced, the piston polished, and the valve cleaned and calibrated.

The I i 2 li i al l HPCI turb. was tested and was declared operable.

The unit is now in I

lii41Ifull compli ance wi th the requi rements, and no further rerprting is required.

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LER #:

50-321/1981-051 Licensec:

Georgia Power Company Facility Name:

Edwin I. Ilatch Docket #:

50-321

Narrative

Report for LER 50-321/1981-051 On 6-7-81, at 0310 and with Unit 1 in the startup mode holding at 150 lbs Rx pressure and 4% thermal power the llPCI Turbinc Mechanical Overspeed Trip

Test, ilNP-1-5289 was being performed.

As per the procedure the flPCI turbine was uncou-pled from the pump, thereby making the system temporarily inop.

Requirements of Tech Specs 3.5.D.2 (RCIC, ADS, LPCI, CSS operabic) were met prior to the uncoupling of the turbine.

The overspeed test was performed, and the turbine would not trip at or below 5000 rpm as specified in Tech Specs tabic 3.2-2-2 for llPCI turbine overspeed trip setpoint.

No signif-icant event occurred.

This was determined reportable under Tech Specs section 6.9.1.9.b.

The reason for the turbine's failure to trip was due to the mechanical trip ball being broken due to the ball and tappet not having proper clearance between the ball and pin type emergency governor weight.

The ball and tappet was replaced and the cicarance calibrated.

The test was repeated and was unsuccessful due to improper reset timing.

A vendor represen-tative was called on site, and upon further investigation it l

was found that the Robert Shaw diaphragm control valve (model VC-210) was not functioning resulting from deposits in the valve body obstructing the movement of the valve.

Also the l

mechanical trip piston was

scored, thus, preventing smooth movement of the piston in the cylinder.

The diaphragm control valve was cleaned and recalibrated, and the trip piston was polished to a satisfactory condition.

On 6-12-81, the over-speed test was performed and was satisfactory; the turbine was recoupled, and on the same date llN P 3 30 3, ilPCI Pump Operab-

ility, was then performed and was satisfactory.

IIPCI was declared operable.

This is a repetitive

event, ref.

LER 50-321/1980-088, and there were no effects upon public health and safety due to this evcat.

The unit is now in full compliance with the requiremenmts of Tech Specs, and no further reporting is required.

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