ML18153B571

Forwards Investigation Summary Re Inservice Insp Exam of Class 1 Piping Sockets Welds,Per 881026 Meeting. Investigation Concluded That Observed Indications Not Svc Induced

ML18153B571
Person / Time
Site:	Surry
Issue date:	01/13/1989
From:	Cartwright W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.)
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
88-689B, NUDOCS 8901180418
Download: ML18153B571 (6)

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,. VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 W, R. CARTWRIGHT VICE P""'BSIDBNT January 13, 1989 NUCLEAR United States Nuclear Regulatory Commission Serial No. 88-6898 Attention: Document Control Desk NO/DAS:vlh Rl Washington, D. C. 20555 Docket Nos. 50-280 50:...281

• License Nos. DPR-32 DPR-37 Gentlemen:

VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNITS 1 AND 2 CONFIRMATION OF ACTION LETTER CLASS 1 PIPING SOCKET WELDS

SUMMARY

OF INVESTIGATION Our letter (Serial No.88-689). of October 19, 1988, in conjunction with commitments made during a meeting on October 26, 1988, identified several items which required investigation and appropriate corrective action prior to ~lant restart. One of those items was to complete our investigation of indications found during IS! examination of Class 1 piping socket welds. This letter forwards for your information a summary of that investigation which concluded that the observed indications were not service induced.

Should you have any questions concerning this investigation summary, please do not hesitate to contact us.

W.R. Cartwright Attachment Investigation Summary - Class 1 Piping Socket Weld In_dications

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8901180418 890113 PDR F,

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cc: U. S. Nuclear Regulatory Commission Region II 101 Marietta Street~ N. W.

Suite.2900 Atlanta, Georgia 30323 Mr. W. E. Holland NRC Senior Resident Inspector Surry Power Station Mr. B. C. Buckley NRC Surry Project Manager Project Directorate II-2 Division of Reactor Projects - I/II

Surry Power Station Units 1 &2 Investigation Su11111ary Class I Piping Socket Weld Indications

Surry Power Station Investigation Summary of Class 1 Piping Socket Weld i~dications

1.0 Background

During the present Unit 2 refueling outage, ISi examinations of Class 1 piping socket welds resulted in the report of rejectable indications.

Consistent with Code requirements the inspection sample was increased and expanded to include Unit 1. Eventually, a total of 335 Class 1 socket welds were examined of which 28 were reported to have indications (Unit 1:

31 welds inspected/2 indications; Unit 2: 304 welds inspected/26 indications).

2.0 Evaluation of Indications Using the original evaluation procedure, seven indications were removed under the guidance of a Company engineer. In five cases, the indications were judged to be either the result of initial construction or poor NOE technique. In two cases, the indications ~ere removed without specifically identifying the cause of the indication. No service induced flaws were identified during these initial evaluations.

Because of the need to specifically identify the cause of the remaining indications, a more detailed evaluation procedure was developed with assistance of Babcock and Wilcox. The remaining indications were evaluated using the new procedure. Nondestructive reexaminations performed by the Company Corporate Level III did- not identify any service induced flaws. (Eighteen of these reexaminations were witnessed by either the ANII or the NRC).

In addition, material investigations were performed by both the Company and B&W on a total of 12 weld joints. These material investigations also concluded that the indications were nonrelevant or formed during initial manufacture. No service induced flaws were identified.

A summary of the indications and evaluation conculsions are provided in Table 1.

3.0 Conclusions With the exception of two weld indications which were removed without identification of cause, the investigation was able to conclusively determine that none of the indications were caused by service conditions.

Babcock and Wilcox concurs in this conclusion for the 21 weld joints in which they participated in the evaluation process. The indic~tions in the two unresolved joints were removed with only light grinding (excavation depths were 1/32 inch and 3/64 inch, respectively). It is our opinion that the indications in these two joints were not service related. But, because the evaluation process did not conclusively confirm this position, these two weld joints will be reexamined at least once in the next three

IS! inspection periods to the requirements of the .ISi program in effect at that time. *

• In reviewing why these indicattons had not been identified in previous inspections,* the following observations were made: Requirements of the codes related to the construction and past ISi inspection activities_ are in fact consistent with the above findings. Acceptance criteria were less stringent than present requirements ~nd little or no base material required examination by surface NOE methods.

In conclusion, we have identified no socket weld indications that were service induced flaws and believe that these indications have existed from original construction.

TABLE 1

SUMMARY

OF SOCKET WELD INDICATIONS AND EVALUATIONS Original Final Excavation Weld No. ISI NO. Indication Resolution . De~th 05 VIR-1-4209 Rounded in Weld Porosity 3/64 inch 04 VIR-1-4209 Rounded in Weld Porosity Very Slight 40 VIR-1-4108 Linear in Weld Not resolved 1/32 inch 43 VIR-1-4204 Linear in Weld NRI by Level III 33 VIR-1-4310 Linear in Base Metal Lap 1/16 inch 34 VIR-1-4310 Linear in Base Metal Lap 1/64 inch 50 VIR-1-4310 . Linear jn Base Metal Lap 7/64 inch 18 VIR-1-4213 Linear in Weld NRI

. by Level III 33 VIR-1-4308 Linear in Base Metal NRI by Level III 11 VIR-1-4114 Linear in Base Metal Lap 1/16 inch 13 VIR-1-4114 Linear in Base Metal NRI by Level III 23 VIR-1-4114 Linear in Base .Metal Lap

• 1/64 inch 15 VIR-1-4108 Linear in Base Metal Laps Lab Analysis 20 VIR-1-4209_ Linear in Weld Undercut Lab Analysis 21 VIR-1-4209 Linear in Weld Surface Condition 1/64 inch 15 VIR-1-4308 Linear in Base Metal Lap 1/16 inch 16 VIR-1~4308 Linear in .Base Metal Lap/LOF 1/16 inch+

and Weld 3/32 inch 18 VIR-1-4308 Linear in Base Metal Manufacturing Defect 1/32 inch 22 VIR-1-4313 Linear in Weld Acceptable Size by Code 12 VIR-1-4213 Linear in Weld and Not Resolved 3/64 inch Base Metal 17 VIR-1-4213 Linear in Weld NRI by Level II I 20 VIR-"1-4308 Linear in Base Metal NRI by Level III 11 VIR-1-4213 Linear in Weld NRI by Level III 33 VIR-1-4208 Rounded in Base Metal Arc Strike 1/32 inch 20 VIR-1-4307 Linear in Weld NRI by Level III 21 VIR-1-4307 Rounded in Weld NRI by Level III 06 VPA-1-4213 Linear in Base Metal Lap 1/32 inch 07 VPA-1-4213 Linear in Base Metal Lap and Arc Strike 3/64 inch NRI- Non Relevant Indication