ML18025A479

Interim Report of Reportable Deficiency Defect in RPV Susquehanna Unit 2 Bottom Head Side Plate

ML18025A479
Person / Time
Site:	Susquehanna
Issue date:	11/05/1976
From:	Curtis N W Pennsylvania Power & Light Co
To:	O'Reilly J P NRC Region 1
References
PLA-142
Download: ML18025A479 (4)

Text

TWO NORTH NINTH STREET, ALLENTOWN, PA.18101 1 PHQN~, (215)521 51 IP BIOBrlrQnrll'll Penna%"ania

,'976.Y'ovanber 5, 1976 gnIPHPr rhiLrr2225552rrrl rINHr rtHrdrcrr.

Mr.J.P.O'Reilly Director-Region I U.S.Nuclear Regulatory Qammission 931 Park Avenue King of Prussia, Pennsylvania 19406 SUSQUEHANNA STiRM EU!CZRIC STATICN (SSES)INTERIM REPORT OF.REPORTABLE DEFIC~Cv DEFECT IN RPV UNIT I2 POTCH HEM'IDE PLATE DOCKET NO: 50-388 LICENSE NO: CPPR-102 ERs 100450/100508 FILE 840-4 PLA-142

Dear Mr.O'Reilly:

This relates to a deficiency resulting fram a defect in the RPV Unit I2 bottom head side plate.The contractor has reported that the defect was caused during the rEmoval of a ten~rary support strut.The deficiency was evaluated and reported to Mr.Mattia on October 1, 1976 as being of such conseauence as to be considered as a significant deficiency in construc-tion and, therefore, reportable urger the provisions described in 10CFR Part 50.55 (e), (iii).The impact of this defect is being analyzed by PL, its,contractors, ard a technical consultant, and will be fully addressed in the final, definitive report regarding the deficiency.

It is anticipated that the definitive report will be sukmitted within 30 days aft'er the defect has been raroved and blended.Should it become apparent that this schedule cannot be met, you will be pnxnptly advised.The following is an account of the relevant details of the deficiency, the investigation pursued and the data which have been established to date: A.Chronology of Events 1.The defect in the BPV Unit I2 bottcm head siae plate is believed to have been created about four months ago when a temporary attachment between the vessel and the support skirt was bL22ned off according to CBI Procedure LBP-1.P ENN 5 YL VAN I A POWER 8 L I GH T COMPANY 0'I P Mr.J.P.O'Reilly Page 2 Novanber 5, 1976 2.Due to manpower considerations, the clean up of the attachnent area was delayed until Septanber 28, 1976.In the interim, the activity was under the control of Travel Folder RZK-20, Itan 21A.On Septanber 28, 1976, CBI personnel began rennving metal in the area of the defect.Remrk is allowed by GE Specification 21A9340 which provides for excavation of surface defects to determine their depth.3.The area was excavated to a depth of 15/16" and on Septanber 29, 1976 CBI entered the condition as a defect in their Nonconformance lag.4.On Septanber 30, 1976, GE San Jose notified PL of the defect.After evaluation of the incident, PL unsuccessfully attanpted to reach Mr.Heishnan of NRC Region I at 3:00 p.m.A message was left to return the call.5.Mr.Mattia returned the call at 8:05 a.m.on October 1, 1976 and was advised of the incident.He was informed that the reportability of the defect was being evaluated, and that an interim report or final definitive report, if warranted, auld be suhnitted to the NRC by Ncvanber 1, 1976.6.On Novanber 1, 1976, PL advised Mr.Mattia that the evaluation was not complete a+2 asked for an extension of the report date until November 8, 1976.This extension was granted.B.Anal is of Safe lications l.Evaluation of the impact of'the depth of the defect on the nominal material thickness including reconciliation of the thickness reduction with the stxess report is being pursued.2.The consideration of low cycle, high stress fatigue, due to thermal stress or deterioration of the microstxucture within the heat affected zone is being'studied from a metallurgical aspect.C.Corrective Measures Taken l.On October 10, 1976 CBI issued Request For Acceptance Of Nonconformity As A Deviation (RAD)N8.2.A specific remrk procedure is being prepared to govern the operation.

It is anticipated that the area will be excavated to sound base metal, contour blended, examined by nondestructive examination, acid etched to detexmine that the heat affected zone has been ranoved, and then final inspected.

D.Conclusion This deficiency was discovered during a routine work operation and the inspection activity is under the control of the CBI Quality Assurance Program.This control is assured by the use of the CBI traveler folder which is sequenced such that work will mt progress until the defect is properly dispositioned.

Mr.J.P.O'Reillv Page 3 Novanber 5, 1976 The disposition of the defect is being given full design consideration, including the technical services of a metallurgical consultant.

Remrk will be done in accordance with applicable code and regulatory recuire-ments and will be monitored by PL to assure canpliance.

In the interim, the Cczmission will be advised of any significant issue which may arise.Very truly yours, N.W.Curtis Vice president Eng-ineering e Gcnstructicn JZJ:mcb cc: Mr.Ernst Volgenau (15)Director Office of Inspection and Enforcement U.S.Nuclear Regulatory Camnission Washington, D.C.20555 Mr.G.McDonald Director Of fice of Management Infoxmation and Pnxp:am Control U.S.Nuclear Regulatory Gmmission Washington, D.C.20555