ML19209A852
| ML19209A852 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 07/26/1979 |
| From: | Reed C COMMONWEALTH EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| Shared Package | |
| ML19209A843 | List: |
| References | |
| NUDOCS 7910050480 | |
| Download: ML19209A852 (4) | |
Text
Commonwealth Edison
~
y one First National Plaza. Chicago, lihnois 7 Address Reply to: Post Office Box 767 Chicago, Illinois 60690 July 26, 1979 M"r. James G. Keppler, Director Directorate of Inspection and Enforcement - Region III U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, Illinois 60137
Subject:
Zion Station Unit 1 Disposition of UT Indications in 8" RHR Weld NRC Docket No. 50-295 Reference (a):
January 5, 1979 letter from R. F.
Heishman to Byron Lee, Jr. transmitting IE Inspection Report No. 50-295/78-22
Dear Mr. Keppler:
Per Reference (a), the NRC inspector observed UT shear wave examination of the recirculation loop No. 2, 8
, ^
inch stG less steel RHR return line, weld No. 29.
Indica-tions were noted and recorded during the examination ranging from 20% to 80% of calibration in various locations around the circumference of the weld.
During this inspection, it was generally agreed that this weld would be removed during the next refueling outage and replaced with a new spool.
- However, subsequent in-house discussions at Commonwealth Edison Company have led to the development of the inspection program outlined in Attachment 1 to this letter.
In June 1979, Mr. W. J. Key of your office was verbally informed of Commonwealth Edison's intended course of action.
With your concurrence, the inspection program in will provide the basis for the proper disposition of this issue.
Please address any ad tional questions that you might?have concerning this matter to this office.
Very truly yours, C,(
dUl.301979 Cordell Reed Assistant Vice-President 1
jj27 1910050 attachment
Commonwealth Edison NRC Docket No. 50-295 ATTACHMENT 1 DISPOSITION OF UT INDICATIONS IN ZION UNIT 1 8" RHR WELD L
A continuing examination program on UT indications in an 8" RHR line weld has been conducted at Zion Station as I
-t of the Inservice Inspection Program (ISI).
This weld was identified in IE Inspection Report No. 50-295/78-22 as Weld 29 on Sketch CWE-158.
A subsequent updating of the IST sketches has reidentified this weld as Weld 29 on Sketch CWE-1-4203 which is now the correct reference.
The following is a brief review of inspections to date on this weld.
A.
During the Preservice Inspection (Jan. - Feb. 1974) a mid-wail reflector was identified in weld 29.
At that time, the indications appeared to be due to geometric or metallurgical reflectors resulting from the anomalous behavior frequently observed in the ultrasonic beam path in austenitic materials.
B.
Re-examination during the first Inservice Inspection (March - May,1976) identified the indications as being identical to the preservice indications, therefore, acceptable for continued operation.
C.
Re-examination during the second ISI (Nov. 1977) again identified the indications as exhibiting no appreciable changes in size or amplitude.
At this time, additional mid-wall reflectors, not of sufficient amplitude to have been classified as recordable, were scrutinized and documented to provide information for future comparisons.
Since the recordable indications showed no change and since all observed reflectors were seen at mid-wall locations, they were again evaluated as not being service induced.
Therefore, the weld was found acceptable for further operation and scheduled for examination during the next two refueling outages.
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Commonwealth Edison NRC Docket No. 50-295 I,
D.
The weld was examined for a fourth time during the Fall 1978 refueling outage (Sept. - Nov., 1978) with the indications previously noted identified.
No appreciable changes in these indications were
(
found and especially none that could be attributed to growth.
i However, a small, acceptable mid-wall indication not noted during the previous inspections was observed.
The data did not appear to indicate the reflector was a service-induced flaw, but the possibility of anomalous ultra-sound behavior made any qualitative determination indecisive.
Thus, at the conclusion of the Fall 1978 refueling outage, the following was left unresolved:
1)
The newly identified reflector was in fact service indu.~ed, or 2)
The reflector was not observed previously due to technique variables or anomalous ultra-sound behavior.
In order to resolve this issue, commonwealth Edison will perform during the Fall 1979 refueling outage the following in-spections to assure that the ultrasonic reflector is not growing and the indication does not communicate with the ID wall:
A)
A repeat of the Ultrasonic Inspections (UT).
This will provide data to be compared with previous inspections.
B)
Radiographic Inspection (RT).
This will allow comparison to the original construction radiographs.
Shots can be made at various angles to allow determination of through wall location.
Radiographs showing the in-dication to be purely mid-wall will confirm that no service induced mechanism is involved.
1127 135
3-C)
Internal Visual Inspection (VT).
If the radiographs are inconclusive, a visual inspection of the inside e
surface of the weld area will be performed.
This will allow confirmation of whether the indication communicates with the ID wall.
t Upon completion of this inspection program,_ this issue will be disposed as follows:
1)
Upon confirmation of the indication as purely mid-wall and exhibiting no significant growth, the weld will ba considered acceptable for further safe operation; or 2)
If the above inspections are inconclusive or if any of the inspections indicate that the indication is a service-induced flaw, the weld will be repaired or replaced.
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1127 136 9
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