ML18037A294

Interim Deficiency Rept Re Reactor Pedestal Embedment PB-37. Welding Procedure Deviations Found in Eight Sections of Rebar Which Were Field Welded to Shear Bars.Procedures for Welding Not Qualified.Final Rept to Be Submitted 801208

ML18037A294
Person / Time
Site:	Nine Mile Point
Issue date:	10/08/1980
From:	Rhode G NIAGARA MOHAWK POWER CORP.
To:	Robert Carlson NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 8010160492
Download: ML18037A294 (6)

Text

"* 'l REGULA RY INFORMATION DISTRIBUTI SYSTEM (RIDS)

ACCESSION NSR:0010100 '92 DOC ~ D TE: 00/10/00 NO ARIZED: NO DOCKET rr FACIL:50 410 Nln'e Ni le Po{nt Noel ear Stat onr Unit .2r 'N,1egana Nona 05000410 1

AUTH. NAME AUTHOR AFFILIATION RHODEFG.K. Niagara Mohawk Power Corp. ~P],

REC IP. NAME RECIPIENT AFFILIATION CARLSONFR ~ . 'egion 1F PhiladelphiaF Reactor Construction L Engineeri

SUBJECT:

Inter'im deficiency rept re reactor pedestal, embedment PB-37..

Melding procedure deviations found in eight sections of rebar'hich were field welded to sheaI bars. Procedures fo.r welding not qualified ot tested. Final reptl submitted 801208.

DISTRIBUTION CODE: B019S COPIES RECEIVED:LTR ( ENCL SIZE:

TITLE: Construction Deficiency Repor t'10CFR50.55E)

NOTES!

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME ,LiTTR ENCL ID CODE/NAMEi LrTTR ENCL ACTIONe A/D LICENSNG 04 YOUNGBLOODiB 05 RUSHBROOKgM; 06 KIPERg K ~ 07 INTERNAL: AD'/RCI'/IE 17 1 AEOD 18 ASLBP/J ~ HARD 1 D/DIR HUM FAC15 EDO L STAFF 19 1 EQUIP QUAL BR 1 1 HYD/GEO BR 22 1 ISE" 09 L'IC QUAL( BR. 12 1 MPA 20 NRC PDR 02 1 OELD 21 REV 13 1 QA BR 14 F 01. 1 RUTHERFORDiN ~ IE.

STAN RDS DEV'1 1 EXTERNAL: ACRS 16 16 1 LPDR 03 NSIC>> 08 1 Ogp

/yo(

TOTAL NUMBER OF>> COPIES REQUIRED! LTTR 39 ENCL"

l flf W l,

, c) 1[

J k 1

I i

1'I, ' 4 h l

'lg

7 N1AGAPA

<l MOHA%f(

474-1511 NIAGARA MOHAWK POWER CORPORATION/300 ERIE 8OULEVARD WEST, SYRACUSE, N,Y. 13202/TELEPHONE (315)

October 8, 1980 Office of Inspection and Enforcement Region I Att: Mr. R. Carlson, Chief Reactor Construction and Engineering Support Branch U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406

Dear Mr. Carlson:

Re: Nine Mile Point Unit,2 Docket 50-410 On September 8, 1980 Mr. McGaughy of your staff was notified of a potential 'reportable deficiency under 10CFR50.55(e) at Nine Mile Point Unit 2 involving reactor pedestal embedment PB-37. The following deviations have been identified with eight sections of No. 14 rebar which were field welded to shear bars on reactor pedestal embedment PB-37:

l. The welding procedure used was an ASME Section III procedure but was not qualified to the code applicable for the work performed ( i.e. AWS D12.1) .

2. The welder was qualified to,ASME Section IX but not to the applicable code (i.e. AWS D12.1).

3. The welds were not tested using sister splices as required by the specification.

This particular cadwelding was limited to these eight rebar welds aTId has been evaluated as follows:

PpK (o

S0 >0>60 /~2

1 J j l

Page Two October 8, 1980

1. The welding procedure used for.. the welding of No. 14 rebar to plate PB-37 is qualified to ASME Section Ii"I and was used with 300oF preheat. This procedure is adequate for the work performed and will provide acceptable results. This has been verified by comparing the welding parameters specified in the procedure used with those specified .in a procedure qual ified to AWS D12.1.

2. The 'welding procedure used is comparable to an approved AWS D12.1 procedure and the welder was qualified to the same procedure. A review of the welder's previous qualifications indicates that the rebar and plate.

that he actually welded are .of essentially the same chemistry as the materials he was qualified to weld.

3. A visual inspection was performed and documented for these rebar yields indicating that surface cracks or discontinuities were not present.

4. Initially, the design of embdement PB-37 .was based on a'pullout load of 405 Kips. Subsequently, the actual pullout load to be resisted by this plate for the worst loading condition has been determined to be 336 Kips.

Eight No. 14 rebar welded to the plate can provide maximum pullout capacity of 704 kips. Therefore, the welds in, question will not be stressed to full design load. Design calculations of the plate indicate that maximum pullout load on any single No. 14 rebar is 31.4 kips for the worst loading condition, which is far less than the allowable load of 88 kips.

I In order to further assure the adequacy of the welding procedure used, three sister splices will be prepared using the aforementioned ASME Section III procedure and tested for tensile stress. Action to prevent recurrence is being evaluated. A final report containing this information .will be sent to you by December 8, 1980:

Very truly yours, NIAGARA MOHAWK POWER CORPORATION era d K. R d Vice President System Project Management PEF:bd xc=.D~~ctoooMI:napery& on-5=&Tovcemen~

U. S. Nuclear Regulatory Commission Washington, D. C. 20555

,)

~ ~

J