ML20093G427

Interim Deficiency Rept 55-83-10 Re Welding Defects on Containment Liner Dome Closure Weld Seam.Initially Reported on 831201.Sargent & Lundy Evaluation Continuing.Final Rept Will Be Submitted in 90 Days

ML20093G427
Person / Time
Site:	Clinton
Issue date:	07/11/1984
From:	Hall J ILLINOIS POWER CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
References
55-83-10, U-10175, NUDOCS 8407240148
Download: ML20093G427 (4)

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16 05-L ILLIN0/8 POWER COMPANY y y.10175 CLINTON POWER STAflON. P.O. BOX 678. CLINTON. ILLINOIS 61727 July 11, 1984 Docket No. 50-461 Mr. James G. Keppler Regional Administrator Region III U.S. Nuclear. Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137

Subject:

Potential 10CFR50.55(e) Deficiency 55-83-10 Weld Deficiencies on Containment Liner Dome

Dear Mr. Keppler:

On December 1,1983, Illinois Power notified Mr. F.

Jablonski, NRC Region III (ref: IP memorandum Y-18886 dated

. December 1, 1983) of a potentially-reportable deficiency per 10CFR50.55(e) concerning welding deficiencies identified on the containment liner dome closure weld seam. This initial notification was followed by two (2) interim reports (ref: IP letter U-10116, D. P. Hall to J. G. Keppler dated December 29, 1983: and IP letter U-10140, D. P. Hall to J. G. Keppler dated April 6, 1984). Our investigation of this issue continues, and this letter represents an interim report inLaccordance with 10CFR50. 55 (e) (3) . '

Statement of Potentially Repcrtable Deficiency / Background -

During the removal of temi.orary attachments from the con-tainment liner dome, vender.weldin

-Baldwin Associates-(BA) personnel'g, on deficiencies'were the' containment liner observed dome.by closure weld seam (designated R2-R3), fabricated by-Chicago Bridge & Iron Co. (CB&I). The deficiencies include areas of undercut, porosity, incorrect weld profile, arc strikes, and several small cracks. Also found were~ dimensional tolerance violations during base' metal ~ fit-up of the weld, and the presence -

of a foreign substance on the seam weld.. An evaluation-is being performed to determine the full extent and significance of'these conditions on operational safety of Clinton Power Station ~(CPS). l i

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Mr. James ' G. Keppler Page 2 Investigation Results/ Corrective' Action Illinois Power has prepared and implemented an investigation plan to identify and evaluate the extent and nature of weld deficiencies and other irregularities noted by Baldwin Associates

_ personnel. .The-investigation han proceeded-in the following

. manner:

1. Illinois Power retained the servi'ces of a chemist from Southwest Research Institute (SWRI).to inspect and to obtain.and analyze a sample of the foreign-substance found on the' dome weld. SWRI reported that the foreign substance was chewing gum placed over the weld area after the primer paint had been applied. The area where the gum was removed was subsequently cleaned and magnetic particle (MT)' examined. No adverse indications were found, indicating that the gum had not masked any weld defects. It has been concluded that

.this was an isolated incioent.

2. The liner areas reported as dimensionally out of tolerance were evaluated by Sargent & Lundy. This evaluation determined that the identified dimensional deviations will not affect the functioning of_the liner.

3. An area twelve (12) inches on either side of the-closure seam R2-R3 and several. adjacent areas exhibiting suspect visual indications were cleaned and examined by magnetic particle testing by U.S. Testing Company and then visually -inspected _ by - BA. The examination / inspection was performed:in 10' increments around the circumference of the R2-R3 weld, and.

resulted in the issuance of 36 Nonconformance: Reports, primarily for adverse visual indications. The visual-inspection criteria used_by~BA.was, however,fdifferent from that.used bylCB&I.at-the' time of construction.

Two~(2) small cracks.and two (2) linear-MT-indications-were identified by :the examinations. . These adverse indications areLbeing explored furtherEto determine the-

. relevance / significance;of.the indications:and the need.

for-repairs.

Illinois Power retaindd the services :of an independent third party,cBrand ExaminationLServices and Testing.Co.

(BESTCo),ftolact as'IP's Designated Reviewer,.to .

.further evaluate:the weld surface condition,. visual. . .

inspection results,:and MT examination ~results. The Designated. Reviewer evaluated _.the MT. procedures used'by CB&I and U.S. Testing Company,'therfa,'i. cation specification ~, andLapplicable design coues_for the.

original work.

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11r'. 1 James : G; = Reppler. . .Page 3 Additional'MT examin'ations were; performed by.the Designated Reviewer to further evaluate the adequacy of installation and investigation work performed on the dome welds.

. The results of our. investigation, following completion of activities by the' Designated Reviewer (BESTCo)..are as follows:

1. The surface of the R2-R3 weld is suitable for MT inspection.

2. Two (2) areas on vertical welds intersecting R2-R3 are  !

considered unsuitable for MT and will be cleaned and-  !

reinspected (NCRs 14348 and 14349).

3. The MT' inspection of the R2-R3 weld was valid at the time'it was performed by Chicago Bridge.& Iron (CB&I).

CB&I had also vacuum box tested this weld for leakage t per specification requirements, and found it acceptable.

4.- -Indications noted'now must be explored for relevance (NCRs 14360, 13402, and 14640).

5. The crack in the liner must be. repaired (NCR 14340).

6. The weld area previously reported with gum overlayed is acceptable (NCR 15513).

7. Welds.on the repair plate at azo 9' will be excavated /

repaired (NCR 14927).

8. . Areas with out of tolerance liner geometry.are acceptable as is'(NCR 12824).

-Safety Evaluation / Significance Investigation of this' issue ~is proceeding at this time'to-determine the significance of the.-identified welding deficiencies. The final disposition'to several NCRs.is pending

'the excavation of designated weld: areas'and MT:reius?ections.

The.results.'of these MT reinspections.could. add to the significance of this; investigation. Sargent &:Lundy will bel requested to: provide an; evaluation of the significance to the safe operation of Clinton Power Station in-light of the confirmed Lcrack in the : liner. 1The determination: of 'the .reportability of

.this-matter will'be made uponfIllinoi's Power's-review of-Sargent'

&:Lundy's evaluation. It:is. expected'that approximately ninety-  !

l(90) days will'be-'necessary tolfurther' evaluate this issue'and to'

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provide 1a final report on.the' matter.-

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-Ilr -Janna G.-Ksppler Page 4 i

. . 1We trust that:this interim report provides sufficient background information to perform a general assessment of this potentially reportable deficiency, and adequately describes our overall approach to resolve the issue.

Sincerely yours, D. P. Hall

- Vice President RLC/ lag cc: NRC Resident Office Director-Office of I&E, USNRC,_ Washington, DC 20555 Illinois Department of Nuclear Safety INPO Records Center -

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