05000265/LER-1980-012-03, /03L-0:on 800428,reactor Water Conductivity Exceeded 10 Umhos/Cm Tech Spec Limit.Caused by Depleted Demineralizers.Unit Shutdown Initiated.Demineralizers Regenerated & Low Conductivity Coolant Added to Reactor

/03L-0:on 800428,reactor Water Conductivity Exceeded 10 Umhos/Cm Tech Spec Limit.Caused by Depleted Demineralizers.Unit Shutdown Initiated.Demineralizers Regenerated & Low Conductivity Coolant Added to Reactor

ML19316B115
Person / Time
Site:	Quad Cities
Issue date:	05/27/1980
From:	Vahrenwald J COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19316B109	List: 05000265/LER-1980-012, Forwards LER 80-012/03L-0 05000265/LER-1980-012-03, /03L-0:on 800428,reactor Water Conductivity Exceeded 10 Umhos/Cm Tech Spec Limit.Caused by Depleted Demineralizers.Unit Shutdown Initiated.Demineralizers Regenerated & Low Conductivity Coolant Added to Reactor
References
LER-80-012-03L-04, LER-80-12-3L-4, NUDOCS 8006110330
Download: ML19316B115 (2)

LER-1980-012, /03L-0:on 800428,reactor Water Conductivity Exceeded 10 Umhos/Cm Tech Spec Limit.Caused by Depleted Demineralizers.Unit Shutdown Initiated.Demineralizers Regenerated & Low Conductivity Coolant Added to Reactor

Event date:
Report date:
2651980012R03 - NRC Website

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On April 27, 1980, at 5:25 p.m. Unit Two was placed in the STARTUP mode and the l

reactor was made critical at 6:50 p.m.

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for a five month outage. At 3:45 4.m. on April 28, 1980, reactor water analysis I

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1. o to i i limi t of TS 3.6.C.3 The chloride-oxygen concentration during this occurrence was l

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system after a five month outage, contributed to by the introduction of new clean-up [

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of the demineralizers. At 5:45 a.m. conductivity was decreased to 9 umhos/cm.

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LER NUMBER: 80-12/03L-0 11.

LICENSEE NAME: Commonwealth Edison Company quad-Cities Nuclear Power Station Ill.

FACILITY NAME: Unit Two IV.

DOCKET NUMBER: 050-265 V.

EVENT DESCRIPTION

On April 27, 1980, at 5:25 p.m.,

Unit Two was placed in the STARTUP mode and the reactor was made critical at 6:50 p.m.

Prior to startup, the unit had been shutdown for a five month outage. At 3:45 a.m., on April 28, 1980, analysis of reactor water Indicated conductivity had increased to 13 umhos/cm, which was in excess of the 10 umhos/cm limit of Technical Specification 3.6.C.3.

At this time the Chemistry Technician notified the Shif t Engineer and an orderly unit shutdown was initiated.

Following this, reactor water clean-up demineralizers and condensate demineralizers were regenerated. At 5:45 a.m. reactor water conductivity decreased to 9 umhos/cm and reactor startup was resumed.

VI.

PROBABLE CONSEQUENCES OF THE OCCURRENCE:

Technical Specification 3.6.C.3 is concerned with limits for conductivity and chloride concentration to prevent stress corrosion cracking of stain-less steel.

Figure 4.6-1 of Technical Specification 3.6.C; Limiting Conditions for Operation Bases, indicates the stainless steel failure boundary for ranges of chloride-oxygen combinations in reactor water.

The chloride-oxygen concentration for Unit Two reactor water during this startup never exceeded the 3.6.C.3 limits and subsequently was well below the Figure 4.6-1 failure boundary. Thus, the safety consequences of this cccurrence are minimal.

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CAUSE

The cause of this occurrence was due to depleted demineralizers. The exact cause of the decrease in reactor water quality is not known. A possible cause being the effect of startup temperatures on the system af ter a five month outage contributed to by the introduction of new clean-up system piping.

During the outage the clean-up system piping was modified to improve clean-up pump reliability. Main condenser tube leaks were also deemed probable.

Vill. CORRECTIVE ACTION:

An orderly unit shutdown was initiated. The reactor water clean-up de-mineralizers and condensate demineralizers were regenerated and low con-ductivity coolant was added to the reactor. At 5:45 a.m. reactor water conductivity decreased to 9 umhos/cm and reactor startup was resumed. On April 29,1980, reactor water conductivity had decreased to I umho/cm. On May 18,1980, during a weekend outage, a number of main conder.ser tube leaks were detected and were repaired by plugging tubes.