ML20137E418

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Forwards Interim Rept 85-M-017, Metallurgical Evaluation of Recirculation Piping Ctr Cross Surface Cracking Following Induction Heat Stress Improvement Grand Gulf Station Unit 1, Per 851115 Request
ML20137E418
Person / Time
Site: Grand Gulf Entergy icon.png
Issue date: 11/20/1985
From: Dale L
MISSISSIPPI POWER & LIGHT CO.
To: Harold Denton
Office of Nuclear Reactor Regulation
Shared Package
ML20137E425 List:
References
AECM-85-0372, AECM-85-372, TAC-60165, NUDOCS 8511270254
Download: ML20137E418 (2)


Text

4-4 m))

EulkkiltilddB MISSISSIPPI POWER & LIGHT COMPANY Helping Build Mississippi P. O. B O X 164 0. J A C K S O N. MIS SIS SlP PI 39215-1640 November 20, 1985 NUCLE AR LICEN$1NG & $AFETY DEPARTMENT U. S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, D. C. 20555 Attention: Mr. Harold R. Denton, Director

Dear Mr. Denton:

SUBJECT:

Grand Gulf Nuclear Station Unit I Docket No. 50-416 License No. NPF-29 Preliminary Evaluation of Recirculation Crosses After Induction Heat Stress Improvement (IHSI)

AECM-85/0372 In the current Fall 1985 outag-c, Mississippi Power & Light (MP&L) elected to conduct IHSI on the Grand Gulf Nuclear Station (GGNS) Unit I recirculation system welds susceptible to integranular stress corrosion cracking.

Indications were revealed in the recirculation system cross forgings during post-IHSI inspections.

In a telephone conversation on November 15, 1985, Mr. Warren Hazeleton of your staff requested that MP&L submit a report on the status of MP&L's evaluation of the indications to dete.

The attachment to this letter is an interim report as requested presenting MP&L's p.eliminary investigation of the subject indications and an overview of the GGNS Unit 1 IHSI results. The report includes:

1. A background discussion of IHSI on the recirculation crosses.
2. Field observations and actions.
3. Metallurgical evaluation.
4. IHSI residual stress and' fracture mechanic analysis.

As presented in the attached report, one significant conclusion is that the grain boundary defects were not caused by IGSCC.

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AECM-85/0372 Page 2 If any additional information is needed, please contact this office.

Yours truly, L. F. Dale Director GCS/MLC/JGC: dam

Attachment (Originals of . photographs to GGNS NRC Project Managers only:

L 1L. Kintner - NRR and R. E.. Carroll - Region II) cc: Mr. T. H. Cloninger-(w/a)

Mr. 0. D. Kingsley, Jr. (w/a)

Mr. R. B. McGehee (w/a)

Mr. N. S. Reynolds (w/a)

'Mr. H.-L. Thomas (w/o)

Mr. R. C. Butcher (w/a)

Mr.-James M. Taylor,' Director (w/a)

Office of Inspection & Enforcement-U. S. Nuclear. Regulatory Commission Washington, D. C. 20555

'Dr. J. Nelson Grace, Regional Administrator (w/a)

U. S. Nuclear Regulatory Commission

' Region II 101 Marietta St., N. W., Suite 2900 Atlanta,. Georgia 30323 l

J14AECM85111801 ~2

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