ML20084S622

AO 50-265/75-15:on 750426,reactor Made Critical W/Reactor Water Chloride Concentration Exceeding Tech Spec Limit. Caused by Unplugging of Condenser Tube.Condensor Tube Replugged

ML20084S622
Person / Time
Site:	Quad Cities
Issue date:	05/05/1975
From:	Kalivianakis N COMMONWEALTH EDISON CO.
To:	Oleary J Office of Nuclear Reactor Regulation
Shared Package
ML20084S625	List: ML20084S622 ML20084S634
References
AO-50-265-75-15, NJK-75-256, NUDOCS 8306170137
Download: ML20084S622 (4)

Text

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May 5, 1975 N.~s[

Mr.* John F. O' Leary, Di rector Directorate of Licensing Regulation

-U. S. Nuclear Regulatory Commission Washington, D. C. 20545

Reference:

Quad-Cities Nuclear Power Station Docket No. 50-265, DPR-30 Appendix A, Sections 1.0.A.2, 3.6.C.3, 6.6.B.I.a

Dear Mr. O' Leary:

Enclosed please find Abnormal Occurrence Report No. 50-265/75-15 for quad-Cities Nuclear Power Station. This occurrence was previously reported to Region li t , Directorate of Regulatory Operations by telephone on April 27, 1975 and to you and Region Ill, Directorate of Regulatory Operations by telecopy on April 28, 1975 This report is submitted to you in accordance with the req 0lrements of Technical Specification 6.6.B.I.a.

Very truly yours, COMMONVEALTH EDISON COMPANY ,

QUAD-CITIES NUCLEAR POWER STATION ,# 4.ga ,7

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REPORT NUMBER: A0 50-265/75-15 6

,, REPORT DATE: May 5, 1975 -

OCCURRENCE DATE: April 26, 1975 FACI LITY: quad-Ci ties Nuclear Power Station Cordova, Illinois 61242 IDENTIFICATION OF OCCURRENCE:

Reactor made critical with reactor water chloride concentration greater than 0.1 ppm.

CONDITIONS PRIOR TO OCCURENCE:

Unit 2 had been shutdown following the initial post-refueling startup to change control rod patterns.

DESCR!PTION OF OCCURRENCE:

The unit was being started up following the cycle one refuel outage. The following events occurred:

Date Time Event Conductivity Chlorides 3/24 9:05 pm Pulling rods for criticality 10: 12 pm Critical Reactor water samples during startup 1 pmho/cm <0.03 ppm 3/25- 7:30 pm Reactor water sample 2 pmho/cm 0.075 ppm 11:30 pm Reactor water sample 5.8 pmho/cm 0 32 ppm 3/26 1:45 am Generator synchronized 1:20 pm Shutdown for control rod pattern change 5:00 pm Reactor water sample 8.65 pmho/cm 0.295 ppm 7:02 pm Pulling rods for crl'ticality

' Shortly thereaf ter, it was realized that Technical Specification 3.6.C 3 .

had been exceeded by starting' up with a chloride concentration greater than 0.10 ppm. An orderly shutdown _ commenced at 8:32 pm on April 26, 1975

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. . s A0 50-265/75-15 May 5, 1975 4 i

t DESIGNAT10H OF APPARENT CAUSE: ,

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. Equipment failure I 9

The apparent cause of this occurrence is attributed to a reoccurring com-  !

ponent failure. While Investigating for a possible condenser tube leak {

on April 28, it was discovered that the plug in a previously identified leaking condenser tube had come out, thus allowing cooling water inleakage j

into the hotwell and subsequent high Ion concentrations in the reactor.

ANALYSIS OF OCCURRENCE: .

Any stress corrosion damage resulting from chloride attack on the system or its components is negligable due to the conservative nature of the limit and the short time the reactor'was operated in this manner. There were no hazards or potential hazards on the health and safety of the public.

CORRECTIVE ACTION: F p

The initial corrective action was to initiate reactor shutdown. This was done at 8:32 pm April 26. After completion of shutdown, blowdown from the reactor to the hotwell commenced so that the condensate domineralizer system and the condensate makeup could be used to reduce the conductivity and the

, chloride condentration. By 8:45 am April 27, the conductivity had been reduced to 1.15 pmho/cm and the chloride concentration to less than .03 ppm. At 11:05 am April 27, control rods were pulled for another startup.

By 3:05 am April 28, an orderly shutdown was again initiated due to a con-ductivity of 3 05 pmho/cm in the reactor water and I pmho/cm in the hotwell.

The chloride concentration during this period from startup to shutdown was maintained at 0.03 ppm or less. Subsequent identification and reptugging 4 of a previously identified leaking condenser tube corrected the problem.

e FAILURE DATA:

There is no previous data of a reactor startup with condenser cooling water inleakage. Previous condenser leaks have occurred during power operation. ,

Cumulative experience with condenser tube leaks has shown there to be no adverse safety implications since corrective action has always been quickly taken to re-establish the reactor water quality within allowable limits.

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