ML20147G671

Forwards Comments Re Insp Plan & Proposed Mitigation & Repair of Inconel Butter Welds.Comments Should Be Addressed in Outage Insp/Repair Rept to Be Submitted at Least 2 Wks Prior to Restart of Unit 2 from Reload 7 Outage

ML20147G671
Person / Time
Site:	Brunswick
Issue date:	03/02/1988
From:	Sylvester E Office of Nuclear Reactor Regulation
To:	Utley E CAROLINA POWER & LIGHT CO.
References
TAC-66546, NUDOCS 8803080293
Download: ML20147G671 (3)

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Docket No. 50-324 DISTTRIBUTION:

jN EJordan <

NRC & Local PDRs JPartlow Mr. E. E. Utley PD21 r/f ACRS(10)

Senior Executive Vice President SVarga Power Supply and Engineering & Construction Glainas l Carolina Power & Light Company EAdensam l P. O. Box 1551 BMozafari l Raleigh, North Carolina 27602 ESylvester '

l CCheng l

Dear Mr. Utley:

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SUBJECT:

BRUNSWICX STED, ELECTRIC PLANT, UNIT 2. INTERGRANULAR STRESS CORROSION CRACK 1(iG INSPECTION PLAN (TAC NO. 66546)

The NRC staff has reviewed your submittals dated October 2 and December 30, 1987, regarding the intergranular stress corrosion cracking (IGSCC) inspection / repair [

plan for Unit 2 during the Reload 7 Outage. Your October 2 submittal contained  ;

an indication that the inspections will be performed in accordance with the

draft NUREG-0313, Revision 2, with 72 welds scheduled for inspection using the i

automated GE SMART UT system (where physical clearances will allow).

I Based on the information provided in the October 2 submittal, the proposed IGSCC inspection plan is acceptable. Also, based on the information provided in the December 30, 1987 submittal, as supplemented by infonnation provided during our ,

January 27, 1988 meeting, the use of the mechanical stress improvement process  :'

i (MSIP) on the 28-inch recirculation nozzles, Al and 81, is acceptable.

t l However, we have enclosed coments regarding the inspection plan and the proposed  :

l mitigation and repair of Inconel butter welds. These coments should be ad-dressed in the outage inspection / repair report to be submitted at least two weeks prior to the restart of Unit 2 from the Reload 7 Outage.  ;

The reporting and/or recordkeeping requirements contained in this letter, i affect fewer than ten respondents; therefore OMB clearance is not required ,

l under P.L.96-511. l Sincerely, 8803080293 880302 ADOCK 0500 4 Ernest D. Sylvester, Project Manager

$DR Project Directorate 11-1 Division of Reactor Projects I/II i

Enclosure:

As stated cc w/ enclosure: l See next page l

1 LA 1 rso%p P :DRPR PM:PD21 DRPR h b : DEST D :DRPR P BMozafari ESylvester YCheng EAdensam l 2 88 2/p/88 3/ \ /88 /p/88 }/g/88 l

1 Mr. E. E. Utley. Brunswick Steam Electric Plant Carolina Power & Light Company Units 1 and 2 cc:

Mr. P. W. Howe Mr. C. R. Dietz Vice President Plant General Manager Brunswick Nuclear Project Brunswick Nuclear Project Box 10429 Box 10429 Southport, North Carolina 28461 Southport, North Carolina 28461 Mr. R. E. Jones, General Counsel Mr. H. A. Cole Carolina Power & Light Company Special Deputy Attorney General P. O. Box 1551 State of North Carolina Raleigh, North Carolina 27602 Post Office Box 629 Raleigh, North Carolina 27602 Mr. Mark S. Calvert Associate General Counsel Mr. Robert P. Gruber Carolina Power & Light Company Executive Director Post Office Box 1551 Public Staff - NCUC Raleigh, North Carolina 27602 Post Office Box 29520 Mr. Christopher Chappell, Chairman Board of Comissioners Post Office Box 249 Bolivia North Carolina 28422 Mrs. Chrys Baggett State Clearinghouse Budget and Management 116 West Jones Street Raleigh, North Carolina 27603 Resident Inspector U. S. Nuclear Regulatory Comission Star Route 1 Post Office Box 208  :

Southport, North Carolina 28461 ,

Regional Administrator, Region II U. S. Nuclear Regulatory Comission 101 Marietta Street, Suite 2900 Atlanta, Georgia 30303 Mr. Dayne H. Brown, Chief Radiation Protection Branch Division of Facility Services N. C. Department of Human Resources 701 Barbour Drive Raleigh, North Carolina 27603-2008

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t ENCLOSURE C0t$ENTS ON BRUNSWICK STEAM ELECTRIC PLANT, UNIT 2 INTERGRANULAR STRESS CORROSION CRACKING (IGSCC) INSPECTION PLAN DOCKET N0. 50-324 (TAC N0. 66546)

(1) The October 2,1987 submittal did not provide detailed infomation on how the welds in each category were selected for inspection. We requ2st that such selection criteria be provided at the time of reporting the inspection results. ,

(2) The listing of Category A weldments should also include the piping welds made of low carbon austenitic stainless steel materials such as 316NG and 304L.

(3) In CP&L's submittal, the mechanical stress improvement process (MSIP) and pipelock are proposed for mitigation or repair of selected Inconel butter welds. We verbally infonned CP&L that, depending on the orientation and size of the flaws in the welds, the proposed mitigation or repair of Inconel butter welds may not be acceptable to the staff. In a December 10 '

1987 meeting, CF&L presented a plan to mitigate two axially flawed 28-inch nozzle welds by MSIP for NRC staff information. The proposal was supported by detailed fracture mechanics evaluation. These two nozzle welds were found to contain minor axial flaws during the last refueling outage and were left in an as-is condition. Subsequently, by letter dated December 30, 1987, CP&L again proposed the use of MSIP for these axial flaws in the event that crack growth does not exceed 70% of the throughwall thickness. In a meeting on January 27, 1988, the licensee infonned the staff that during the on-going IGSCC inspection, these flaws were founo to have not grown.

As noted in NUREG-0313. Revision 2, issued by Generic Letter 88-01, "hRC Position on IGSCC in BWR Austenitic Stainless Steel Piping," dated  ;

January 25, 1988, MSIP is considered as an acceptable mitigation process i for IGSCC susceptable weldments. However, it is considered effective only '

when applied to uncracked weldments or weldments with short or shallow circumferential cracks. The details of the use of MSIP at Brunswick l should be addressed in the Reload 7 Outage IGSCC inspection / repair report. l l

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