ML17058B892

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Provides Results of Exams of FW Nozzle A,In Response to Commitment Made in Providing in Part,Results of ISIs Performed on Four Nmpns,Unit 1 FW Nozzles During 1988 Refueling Outage,Per NUREG-0619
ML17058B892
Person / Time
Site: Nine Mile Point Constellation icon.png
Issue date: 08/25/1993
From: Terry C
NIAGARA MOHAWK POWER CORP.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
RTR-NUREG-0619, RTR-NUREG-619 NMP1L-0777, NMP1L-777, NUDOCS 9308310049
Download: ML17058B892 (6)


Text

ar.CKI.ERATE DOCUMENT DIST REGULAT INFORMATION DISTRIBUTIO UTION SYSTEM STEM (RIDS)

ACCESSION NBR:9308310049 DOC.DATE: 93/08/25 NOTARIZED:

NO FACIL:50-220 Nine Mile Point Nuclear Station, Unit 1, Niagara Powe AUTH.NAME-AUTHOR AFFILIATION TERRYpC.D.

Niagara Mohawk Power Corp.

RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Provides results of exams of FW nozzle A,in response to commitment made in 910111 ltr providing in part, results of ISIs performed on four NMPNS,Unit 1

FW nozzles during 1988 refueling'outage,per NUREG-0619.

DISTRIBUTION CODE:

SOOID COPIES RECEIVED:LTR I

ENCL 0 SIZE:

TITLE: OR Submittal: General Distribution DOCKET 05000220 D

NOTES:

RECIPIENT ID CODE/NAME PDl-1 LA BRINKMAN,D.

COPIES LTTR ENCL RECIPIENT ID CODE/NAME PDl-1 PD COPIES LTTR ENCL D

D INTERNAL: ACRS NRR/DORS/OTSB NRR/DRPW NRR/DSSA/SRXB O~C~t B EG FIL 01 NRR/DE/EELB NRR/DRCH/HICB NRR/DSSA/SPLB NUDOCS-ABSTRACT OGC/HDS1 EXTERNAL: NRC PDR NSIC D

D NOTE TO ALL"RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTEI CONTAC1'HE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 504-2065) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

D TOTAL NUMBER OF COPIES REQUIRED:

LTTR 22 ENCL

p 'A r

NIAGARAMOHAWKPOWER CORPORATION/301 PLAINFIELDROAD, SYRACUSE, N.Y. 13212/TELEPHONE (315) 474-1511 August 25, 1993 NMP1L 0777 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C.

20555 Re:

Nine Mile Point Unit 1 Docket No. 50-220 DPR-Gentlemen:

SUBJECT:

NUREG-0619, BWR FEEDWATER NOZZLE AND CONTROL ROD DRIVE RETURN LINE CRACKING By letter dated January 11, 1991, Niagara Mohawk submitted to the Commission the information required by NUREG-0619, "BWR Feedwater Nozzle and Control Rod Drive Return Line Cracking."

NUREG-0619 requires that licensees provide the Commission a detailed report of NUREG-0619 required inspections performed during an outage.

Our January 11, 1991 letter, in part, provided the results of the inservice inspections performed on the four (4) Nine Mile Point Unit 1 feedwater nozzles during the 1988 refueling outage.

As indicated in our letter, seven (7) "recordable" indications were identified on feedwater nozzle "A". These indications were attributed to two (2) separate flaws.

Niagara Mohawk evaluated these flaws using fracture mechanics and determined that continued plant operation was acceptable.

Also, Niagara Mohawk committed to examine feedwater nozzle "A" during the next refueling outage (1993).

The purpose of this letter is to provide you the results of the examinations of feedwater nozzle "A".

The previous indications were found only in Zone 4 of feedwater nozzle "A". However, all four (4) zones of nozzle "A" were examined during Nine Mile Point Unit 1's 1993 refueling outage.

Zones 1, 2 and 3 were examined with the same ultrasonic techniques used during our 1988 outage examinations.

The examinations indicated no recordable indications.

Zone 4 was also examined with the same ultrasonic technique as previously used.

However, the calibration standard was modified to include code allowable 10% notches as well as the previously used 5% notches.

The Zone 4 indications detected in the 1988 outage were seen but not at recordable levels based on either the 5% or 10% notch calibrations.

Electric Power Research Institute sizing techniques were then attempted to see ifan adequate through-wall dimension could be attained on the previously recorded indications.

Although a base signal could be seen, no tip signals were noted with either the Relative Arrival Time technique or the Absolute Arrival Time technique.

Since no tip could be resolved, the source of these reflectors was 930831'0049 '>930825

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Document Control Desk Page 2 determined to be from scratches or inside diameter gD) surface irregularities and not from ID cracking.

These inservice inspection results have been reviewed and approved by a Niagara Mohawk Level IIIexaminer.

Very truly yours, C. D. Terry Vice President Nuclear Engineering JMT/mls 004169GG pc:

Mr. T. T. Martin, Regional Administrator, Region I Mr. R. A. Capra, Director, Project Directorate I-l, NRR Mr. D. S. Brinkman, Senior Project Manager, NRR Mr. W. L. Schmidt, Senior Resident Inspector Records Management

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