BSEP 18-0044, Application of Dissimilar Metal Weld Full Structural Overlay - Reactor Pressure Vessel Nozzles N4A and N4D

Application of Dissimilar Metal Weld Full Structural Overlay - Reactor Pressure Vessel Nozzles N4A and N4D

ML18101A142
Person / Time
Site:	Brunswick
Issue date:	04/11/2018
From:	Wooten B Duke Energy Progress
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
BSEP 18-0044
Download: ML18101A142 (5)

Text

Brunswick Nuclear Plant P.O. Box 10429 Southport, NC 28461 April 11, 2018 Serial: BSEP 18-0044 U.S. Nuclear Regulatory Commission A TIN: Document Control Desk Washington, DC 20555-0001

Subject:

Brunswick Steam Electric Plant, Unit No. 1 Renewed Facility Operating License No. DPR-71 Docket No. 50-325 Application of Dissimilar Metal Weld Full Structural Overlay - Reactor Pressure Vessel Nozzles N4A and N4D

Reference:

Letter from William R. Gideon (Duke Energy) to the U.S. Nuclear Regulatory Commission Document Control Desk, Proposed In-service Inspection Alternative for Application of Dissimilar Metal Weld Full Structural Overlay - Nozzles N4A and N4D, dated March 19, 2018, ADAMS Accession Number ML18078A804 Ladies and Gentlemen:

By letter dated March 19, 2018 (i.e., Reference), Duke Energy Progress, LLC (Duke Energy),

proposed a 10 CFR 50.55a(z)(1) alternative to apply dissimilar metal weld full structural weld overlays (FSWOLs) to the reactor pressure vessel (RPV) nozzles N4A and N4D for the Brunswick Steam Electric Plant (BSEP), Unit No. 1.

Within 14 days of completion of the final ultrasonic testing (UT) examination of the FSWOLs, Duke Energy committed to provide: (1) a listing of indications detected in the overlaid welds and (2) disposition of all indications and, if possible, the type and nature of the indications. Duke Energy completed ultrasonic testing examination of the FSWOLs on the N4A and N4D nozzles on March 31, 2018. The Enclosure to this letter provides a summary of the UT examinations and dispositions.

Please refer any questions regarding this submittal to Mr. Lee Grzeck, Manager - Regulatory Affairs, at (910) 832-2487.

Sincerely,

~ -.Bl&~

Brya7 wooten Director - Organizational Effectiveness Brunswick Steam Electric Plant MAT/mat

U.S. Nuclear Regulatory Commission Page 2 of 2

Enclosure:

Brunswick Steam Electric Plant, Unit No. 1 - Summary of the Ultrasionic Testing (UT)

Examinations and Dispositions for the Reactor Feedwater Nozzles N4A and N4D Full Structural Weld Overlays cc:

U.S. Nuclear Regulatory Commission, Region II ATTN: Ms. Catherine Haney, Regional Administrator 245 Peachtree Center Ave, NE, Suite 1200 Atlanta, GA 30303-1257 U.S. Nuclear Regulatory Commission ATTN: Mr. Andrew Hon (Mail Stop OWFN 8G9A) 11555 Rockville Pike Rockville, MD 20852-2738 U.S. Nuclear Regulatory Commission ATTN: Mr. Gale Smith, NRC Senior Resident Inspector 8470 River Road Southport, NC 28461-8869 Chair - North Carolina Utilities Commission (Electronic Copy Only) 4325 Mail Service Center Raleigh, NC 27699-4300 swatson@ncuc.net Mr. Cliff Dautrich, Bureau Chief North Carolina Department of Labor Boiler Safety Bureau 1101 Mail Service Center Raleigh, NC 27699-1101

BSEP 18-0044 Enclosure Page 1 of 3 Brunswick Steam Electric Plant, Unit No. 1 - Summary of the Ultrasionic Testing (UT)

Examinations and Dispositions for the Reactor Feedwater Nozzles N4A and N4D Full Structural Weld Overlays

Background

By letter dated March 19, 2018, Duke Energy Progress, LLC (Duke Energy), proposed a 10 CFR 50.55a(z)(1) alternative to apply dissimilar metal weld full structural weld overlays (FSWOLs) to the reactor pressure vessel (RPV) nozzles N4A and N4D for the Brunswick Steam Electric Plant (BSEP), Unit No. 1. As committed to in the March 19, 2018 request, the following provides: (1) a listing of indications detected in the overlaid welds and (2) disposition of all indications and, if possible, the type and nature of the indications. Duke Energy has completed ultrasonic testing examination of the FSWOLs on the N4A and N4D nozzles.

Feedwater Nozzle N4A Weld Overlay (Weld Identification: 1B21N4A-2-SW1-2 WOL)

Indication 1 Type: Lack of Bond (Laminar)

Location: Circumferential orientation from 1.75" to 2.75" to datum point Axial orientation 2.9" to datum point Dimensions: Length = 1.00" (Circumferential)

Width = 0.25" (Axial)

Comments: The indication is located outside the preservice examination volume and does not interfere with the examination coverage for the circumferential nozzle weld repaired by the weld overlay installation.

Indication 2 Type: Lack of Bond (Laminar)

Location: Circumferential orientation from 2.0" to 4.25" to datum point Axial orientation 4.0" to datum point Dimensions: Length = 2.25" (Circumferential)

Width = 0.25" (Axial)

Comments: The indication is located within the preservice examination volume and interferes with complete examination coverage for the circumferential nozzle weld repaired by the weld overlay installation.

Disposition The two laminar indications identified in Feedwater Nozzle N4A Weld Overlay (i.e., Weld Identification: 1B21N4A-2-SW1-2 WOL) are considered acceptable based on the following:

The axial separation between the two indications is approximately 1.1". This exceeds the separation requirement "S" of 0.125" per IWA-3330. Therefore, the two indications do not have to be considered as a single continuous indication.

The total Laminar Flaw area is 0.81 in2. This meets the acceptance criteria of IWB-3514.6 and table IWB-3514-3 of 7.5 in2.

BSEP 18-0044 Enclosure Page 2 of 3 The longest linear flaw dimension measured is 2.25". This meets the acceptance criteria of ASME Code Case N740-2 Section 3 Item (a)(3)(a) of the greater of 3" or 10% of the pipe circumference (i.e., 4.3").

Considering an overlay area of 349.5 in2, the total reduction in coverage is less than 1%.

This meets the acceptance criteria of ASME Code Case N740-2 Section 3 Item (a)(3)(b) of less than 10%.

Considering a preservice examination area of 100.66 in2, the total reduction in coverage due to the laminar indications is 0.044% (i.e., 0.004% circumferential limitation +0.04%

axial limitation), which is acceptable based on an allowable loss in coverage of less than 10%.

Feedwater Nozzle N4D Weld Overlay (Weld Identification: 1B21N4D-5-SW1-2 WOL)

Indication 1 Type: Lack of Bond (Laminar)

Location: Circumferential orientation from 13" to 13.75" to datum point Axial orientation 5.3" to datum point Dimensions: Length = 0.75" (Circumferential)

Width = 0.25" (Axial)

Comments: The indication is located outside the preservice examination volume and does not interfere with the examination coverage for the circumferential nozzle weld repaired by the weld overlay installation.

Indication 2 Type: Lack of Bond (Laminar)

Location: Circumferential orientation from 30.75" to 31.25" to datum point Axial orientation 5.3" to datum point Dimensions: Length = 0.50" (Circumferential)

Width = 0.25" (Axial)

Comments: The indication is located outside the preservice examination volume and does not interfere with the examination coverage for the circumferential nozzle weld repaired by the weld overlay installation.

Disposition The two laminar indications identified in Feedwater Nozzle N4D Weld Overlay (Weld Identification: 1B21N4D-5-SW1-2 WOL) are considered acceptable based on the following:

The circumferential separation between the two indications is approximately 17". This exceeds the separation requirement "S" of 0.375" per IWA-3330. Therefore, the two indications do not have to be considered as a single continuous indication.

The total Laminar Flaw area is 0.31 in2. This meets the acceptance criteria of IWB-3514.6 and table IWB-3514-3 of 7.5 in2.

The longest linear flaw dimension measured is 0.75". This meets the acceptance criteria of ASME Code Case N740-2 Section 3 Item (a)(3)(a) of the greater of 3" or 10% of the pipe circumference (i.e., 4.3").

BSEP 18-0044 Enclosure Page 3 of 3 Considering an overlay area of 349.5 in2, the total reduction in coverage is less than 1%.

This meets the acceptance criteria of ASME Code Case N740-2 Section 3 Item (a)(3)(b) of less than 10%.

There is no impact of the identified indications on the preservice inspection volume for weld 1B21N4D-5-SW1-2.