ML20077H068

First Interim Rept on Significant Const Deficiency 85 Re Damage to in-core Instrumentation Guide Tubes.Initially Reported on 830622.Previously Identified as PRD 118.NSSS Vendor & Ae Evaluating Condition.Next Rept by 831031

ML20077H068
Person / Time
Site:	Waterford
Issue date:	07/28/1983
From:	Drummond F LOUISIANA POWER & LIGHT CO.
To:	Jay Collins NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
10CFR-050.55E, 10CFR-50.55E, W3I83-0249, W3I83-249, NUDOCS 8308090586
Download: ML20077H068 (2)

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l OUISIANA f ,42 octARoNoe sineer POWER & LIGHT / P O. box 6008

• NEW ORLEANS LOUISIANA 70174 * (5041 366-2345 MIOCLE SOUTH UTIUTIES SYSTEM July 28, 1983 W3I83-0249 Q-3-A35.07.85 Mr. John T. Collins, Regional Administrator, Region IV E U. S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 1000 .

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SUBJECT:

Waterford SES Unit No. 3 J, 'j8 - 3 f983 t

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fj, Docket No. 50-382 Lf/f '

Significant Construction Deficiency No. 85 o

" Damage to Incore Instrumentation Guide Tubes" --A First Interim Report

REFERENCES:

Telecon dated June 22, 1983 to Mr. M. Boardman Telecon dated July 25, 1983 to Mr. C. Oberg

Dear Mr. Collins:

In accordance with the requirements of 10CFR50.55(e), we are hereby providing two copies of the Interim Report of Significant Construction Deficiency No. 85,

" Damage to Incore Instrumentation Guide Tubes." This item was previously identified as PRD 118.

If you have any questions, please advise.

Very truly yours,

,m m F. J. Drummond Project Support Manager - Nuclear Attachment FJD/WAC/ MAL:keh cc: 1) Director 3) Mr. E. L. Blake Office of Inspection & Enforcement U. S. Nuclear Regulatory Commission Washington, D. C. 20555

2) Director 4) Mr. W.M. Stevenson Office of Management Information and Program Control U. S. Nuclear Regulatory Commission Washington, D. C. 20555 1E- A7 F308090586 830728 PDR ADOCK 05000382 O PDR

j- .1 INTERIM REPORT OF SIGNIFICANT CONSTRUCTION DEFICIENCY NO. 85

" DAMAGE TO INCORE INSTRUMENTATION GUIDE TUBES" r b INTRODUCTION s This report is submitted pursuant to 10CFR50.55(e). It describes damage to the inc' ore instrumentation guide tubes upon' disassembly after Hot Functional Testing.

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To the best of our knowledge, this deficiency has not been reported to the USNRC pursuant to 10CFR21. ,

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. DESCRIPTION Upon disassembly of the Reactor Vessel (RV) internals after hot functional testing four Incore Instrumentation (ICI)fguide tubes on one guide tube cluster were found to be broken at the point where they enter the lower flange of the cluster.

Additionally, wear at points of contact between thefupper flange of the cluster assembly and the nozzle'in the RV head was'noted on this cluster and two others.

The ICI consists csf a string of five vertically st'acked. Rhodium neutron detectors and a core exit thermocouple. There are 56 such assemblies located throughout' the core. The neutron detectors are used as an input to the Core Operating Limit Supervisory System (COLSS) for determination of azimuthal flux tilt magnitude and normal axial power distribution. They also provide, through COLSS, indication of approach to core power limits based on DNBR and local power density.

The Core Exit Thermocouples (CET's) are used as an input to the Inadequate Core Cooling Instrumentation (ICCI) system as described in FSAR Section 1.9.

SAFETY IMPLICATIONS The COLSS and ICCI Systems are not safety related but do provide information to the operator which is important in assessing the plant status. Investigation and analysis is in progress to determine the mechanism which caused the Incore Instrumentation guide tube damage and to evaluate the possible safety impli-Cations.

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CORRECTIVE ACTION TAKEN ,

The NSSS vendor and Architect Engineer are presently evaluating this condition.

An interim or-final report will be provided to the USNRC by October 31, 1983.

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