ML19254E984

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LER 79-027/03L-0:on 790921,Tech Specs Exceeded for Water Reactor Conductivity & Chloride Concentration.Caused by Personnel Error.All Personnel Informed of Importance of Knowing Surveillance Limits
ML19254E984
Person / Time
Site: Quad Cities Constellation icon.png
Issue date: 10/19/1979
From: Markwalter T
COMMONWEALTH EDISON CO.
To:
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19254E981 List:
References
LER-79-027-03L-02, LER-79-27-3L-2, NUDOCS 7911050292
Download: ML19254E984 (3)


Text

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EVENT DESCRIPTION AND PROBABLE CONSEQUENCES h o 2 l Prior to and during startup, T.S. 3.6.C.3 limits were exceeded from 1: 30 a.m. until l o 3 l 10:27 a.m. for reactor water conductivity and from 1:30 a.m. until 2:15 p.m. for r o ,, l chloride concentration. The chloride xygen concentration during this occurrence j g 3 ,

was well below the failure boundary of figure 4.6-1 of T.S. 3.t.C. Thus, the g

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10161l consequences of this occurrence were minimal. An orderly unit'shua'own was s tarted  ;

ITTT'l I and the reactor water cl'eanup demineralizers were regenerated. l o a l l 7 8 9 80 SYSTEM CAUSE CAUSE COVP. VALVE CCDE CCCE SUSCOCE COMPCNENT CODE SUSCOCE SU8 CODE

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i o l The cause of this occurrence was personnel error. The chemistry technician should l lil3 l l have realized the abnormal conductivi ty value and taken appropriate action. Cor- g

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1. LER NUMBER: 79-27/03L-0 ll. LICENSEE NAME: Commonwealth Edison Company Quad-Cities Nuclear Power Station 111. FACILITY NAME: Unit One IV. DOCKET NUMBER: 950-254 "V. EVENT DESCRIPTION:

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On September 2 ,1979, at 0140, Uni t One was placed in the start-up mode and the reactor was made critical at 0255 Prior to startup, the unit had been shutdown for a six day outage, fulfilling requirements of NRC IE Bulletin 79-02. At 0140, analysis of reactor water indicated conductivity was 18 umhos/cm, which exceeds the 10 cmhos/cm limit of Technical Specification 3.6.C.3 During this time, the chemistry technician did not notify the unit operator, and startup continued At 0530, another sampled reactor water indicated that conductivity was 20 mhos/cm, but no notification was given to the operating staff. At 0730, the chemistry staff found the conductivity exceeding the limits for startup and notified the unit operator, whereby control rod insertion was initiated. Following this, reactor water cleanup demineralizers were regenerated and low conductivity coolant was added to the reactor. At 1030, reactor water conductivity decreased to 8.7 umhos/cm and the unit operator was notified to resume unit startup.

At 1050, the laboratory chloride electrode was recalibrated and analysis of reactor water showed the chloride concentration to be 0.18 ppm. The unit operator was immediately notified that reactor water exceeded startup limits f or chloride concentration and an orderly shutdown was initiated. At 1415, the chloride concentration was reduced to 0.035 ppm and the conductivity had droppped to 7.1 pmhos/cm.

The unit operator was notified that both parameters were within limits for startup and control rod insertion was terminated.

As a result of this occurrence, Technical Specification 3.6.C.3 limits were exceeded from 0130 until 1027 for conductivi ty and f rom 0130 until 1415 for chloride concentration on September 21, 1979 VI. PROBABLE CONSEQUENCES OF THE OCCURRENCE:

Technical Specification 3.6.C.3 is concerned with limits for con-ductivity and chloride concentration to prevent stress corrosion cracking of stainless steel. Figure 4.6-1 of Technical Specifica-tions 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 one reactor water during this startup was well below this failure boundary. Thus, the safety consequences of this occurrence are minimal.

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Vll. CAUSE:

The primary cause of this occurrence was due to personnel error; procedure inadequacy was a contributing factor. The chemistry technician should have realized the abnormal conductivity value and taken appropriate action by notifying the unit operator and chemistry staff.

Due to the fact that the limits for reactor water chemistry were not specifically stated on the laboratory surveillance log sheet, the technician was not aware that reactor water conductivity exceeded

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limits for startup; and tnerefore, did not notify the unit operator or chemistry staff of the chemistry results.

The basis of this transient was *.'e reactor water had degraded to an abnormally high conductivity during the outage. Reactor water con-ductivity log indicates the cleanup demineralizers were depleted at 0615 on September 17, 1979 and no corrective action was taken to regenerate the demineralizers.

Vill. CORRECTIVE ACTIONS:

The responsible chemistry technicians were contacted and told the significance of their lack of action during this event. In addition, all radiation / chemistry department technicians were informed of the importance for knowing all surveillance limits and actions that should be taken if these limits are exceeded. To prevent a reoccur-rence of this nature, the start up surveillance procedure will be reviewed and appropriate changes made that will delineate the proper limits and corrective actions to be taken. The frequency of chloride electrode calibration will be increased to accumulate a history of instrument drift so that an interval can be selected which will minimize erroneous analyses.

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