ML20077C637
| ML20077C637 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 07/20/1983 |
| From: | Phyllis Clark GENERAL PUBLIC UTILITIES CORP. |
| To: | Stolz J Office of Nuclear Reactor Regulation |
| References | |
| 5211-83-212, NUDOCS 8307260196 | |
| Download: ML20077C637 (5) | |
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GPU Nuclear Corporation a si p y,New Je sey 07054 201 263-6500 TELEX 136-482 Writer's Direct Dial Number:
July 20,1983 5211-83-212 Office of Nuclear Reactor Regulation Attn: J. F. Stolz, Chief Operating Reactor Branch #4 Division of Licensing U.S. Nuclear Regulatory Cmmission Washington, D. C. 20555
Dear Sir:
'Ihree Mile Island Nuclear Station, Unit 1 ('IMI-1)
Operating License No. DPR-50 Docket No. 50-289
'IMI-l Steam Generator Repair On July 18, 1983 we transmitted to you a copy of Conam Inspection's letter raising eddy current test program concerns, and a copy of the minutes of our July 15, 1983 meeting with Conam to resolve these concerns. 'Ihe attached letter from Conam confirms their concurrence with the meeting minutes. Based on this concurrence, GPUN plans no additional actions.
Sincerely, rP. R. Clark Executive Vice President
/mt Enclosure cc:
H. Silver J. Van Vliet N[
//
8307260196 830720 PDR ADOCK 05000289 P
PDR GPU Nuclear Corporation is a subsidiary of the General Public Utilities Corporation
$0 CONAM INSPECTION 1247 West Norwood ltasca, lilinois 60143 (312) 773-9400 July 18, 1983 GPU NUCLEAR 100 Interpace Parkway Parsippany, New Jersey 07054 Attention:
Mr. R. F. Wilson, Vice President, Technical Functions
Subject:
Memo of Meeting with CONAM Inspection - July 15, 1983
Dear Mr. Wilson:
Following our meeting on July 15, 1983, I am enclosing c copy of the minutes of that meeting that were signed by N. Kazanas, R. Wilson, B. Creech and R. Marlow.
l l
This letter will serve to formally notify you that l
Mr. Boyd Creech and I have thoro',ghly reviewed subject memo and are in full agreement with its content.
I further wish to confirm that subject memo represents an expansion and clarification of my letter dated June 23, 1983 to the attention of Mr. R. Barley.
Very truly yours, A rh*
h---a Boyd F. Creech ichard E. Marlow President Senior Vice President cc:
R. Barley
- CPU Nuclear N. Kazanas D. Slear T. Patterson P. Clark Att: Minutes of Meeting A Unit of The Penn Central Corporat6on h-.
GPU Nuclear NUC MF 100 Interpace Parkway Parmocany. New Jersey 07054 201 263-6500 TELEX 136-482 Wnter's Direct Dial Number:
July 15,1983 Memo to file Meetine with Conam Inspection, Julv 15, 1983 On July 15, 1933, members of Canam Inspection and GPU Nuclear met to review information pertaining to the eddy current examination of the TNI-1 steam generator tubing and the letter from Conam Inspection (Richard Narlow) dated June 23, 1983, Attention:
R. Barley, GPUN, relating to that inspection.
The attendees of the meeting were:
Name Organization Title R. F. Wilson GPU Nuclear Vice President, Technical Functions N. C. Kazanas GPU Xuclear Director, Quality Assurance B. Creech Conam Inspection President R. E. Marlow Canam Inspection Senior Vice President D. G. 51 ear GPU Xuclear Manager, TNI-1 Engineering Projects T. J. Patterson GPU Nuclear Manager, SPP The group was joined later in the afternoon by P. R. Clark, Executive Vice P esident, GPU Nuclear. As a result of the review, the two organizations came to the following conclusions:
1.
The detectability of steam generator tube defects as illustrated by Figure IX-1, GPU Nuclear Report 008, is believed correct as stated.
It is agreed that this detectability is based on a combination of data from EDM notches, synthetic defects, and metallurgical correlations from service and laboratory introduced circumferential IGS cracks.
There is one point of elaboration raised by Canam Inspection which has to do with the eddy current signal when the probe enters a tube support place or the upper tubesheet, causing some loss of detectability.
This charac-teristic signal interference is typical of all steam generator eddy current examinations.
The signal mixing techniques used (based on low gain data) tends to minimize this sensitivity loss.
2.
It is expected that future eddy current testing of the steam generators (tubing) will find new signals from discontinuities below the Figure IX-1 level of detectability. This is due to the fact kinetic expansion may increase the detectability of a given size defect (length and depth) even though size is not increased.
In addition, signals comparable to the background level are being called as defects.
The steam generator inspec-tion with the 0.540 diameter differential probe is nevertheless valid for ID circumferential cracks greater than Figure IX-1 sensitivity thresholds.
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"Julg15,1983 Page Two 3.- Conam Inspection will clarify in a letter to GPU Nuclear their meaning of -
the words " reportable,* *pluggable" and
- serious" as used in the June 23..
~ 1983, letter.. It was understood-at the meeting that this is meant to bet A.
Reportable was used as any discontinuity located by the eddy current examination that is interpreted as greater; than 20% through wall and that must be recorded for engineering evaluation and disposition.
B.
Pluggable was used as any discontinuity located by the eddy current examination that is interpreted as greater than 40% through wall.
.' C.
Serious discontinuities was used as any discontinuity located by the eddy current examination that would be considered as reportable as stated above..
All above definitions were based on Reg. Guide 1.83 and Tech Spec require-ments and did not take into consideration the ECT sensitivity curve Eor IGSAC_(Figute IX-1 in GPUNC Topical Report 008, Rev. 2).
4 Conam Inspection agrees that those items o'E th'e June 23, 1983, letter which could be interpreted as rendering a judgement as to safety significance or-
~ hat should be or should not be plugged was not intended since-they have w
not made a safety evaluation and that they (Conam Inspection) are not
~
- technically qualified or knowledgeable in areas necessary to come to 'these judgements.
5.
The 8x1 detectability improvement identified in the June 23, 1983, Conam Inspection letter was clarified to be improvements in detectability below the. sensitivity limits of Figure'IX-1 in GPUN Report 008, Rev. 2.
It was noted that the current information available-from inspection of the steam generator with absolute probes (i.e., 4x1 or 8x1) based on over 3,200
. cubes examined already exceeds a 99% correlation between the absolute and differential techniques.
6.
The scope, sensitivity and extent of the THI-1 steam generator (tubing) examination conducted during 1982/83 significantly exceeds that done on any other steam generator in the country, to the best of the knowledge of the meeting attendees.
7.
The basic motivation for the June 23, 1983, Conam Inspection letter was to reflect to GPU Nuclear the fact that interpretationand disposition of the reported eddy current signals from future inspections will be more diEEi-cult.. This is due to newly reported signals originating from discontinui-ties that were previously below the detection limits of Figure IX-1 as discussed in 2. above.
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I Memo cc Viiu -
- ol '
- July 15,1983
' Pag,2hree It is the opinion of the GPU Nuclear attendcas at the meeting that (since the eddy current sensitivity and deccctability were reaffirmed) the conclusions of-the safety analysis and SER prepared by GPU Nuclear are valid as written.
(The signature'of the Conam representatives below does not attest to this since Conam Inspection cannot render this opinion technically.)
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N. C. Kazanas R. F. Wil son-Director, Qu' icy Assurance Vice President, Technical Functions GPU Nuclear GPU Nuclear A
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R. E. Marlow B. Creech Senior Vice President President Conam Inspection Conam Inspection l
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