ML20091M252
| ML20091M252 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 06/04/1984 |
| From: | Rybak B COMMONWEALTH EDISON CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| 8728N, GL-84-11, IEB-83-02, IEB-83-2, NUDOCS 8406110193 | |
| Download: ML20091M252 (3) | |
Text
7 f~D Commonwealth Edison
/
) one First Nabonal Ptr23. Chicago. Ilhnois
/. Address Reply tr Post Offica Box 767
( C 7
Chicago, lilinois 60690 A
June 4, 1984 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
LaSalle County Station Units 1 and 2 Response to NRC Generic Letter 84-11 Inspection of BWR Stainless Steel Piping NRC Docket Nos. 50-373 and 50-374 Reference (a):
D. G. Eisenhart letter to All Licensees dated April 19, 1984 (Generic Letter 84-11).
Dear Mr. Denton:
The following is the Commonwealth Edison's response to Generic Letter 84-11, as it applies to the present condition of Stainless Steel Piping at LaSalle County Station.
Item 1: IHSI has been performed on LaSalle Unit 2. before initial start-up.
Recirculation system and branch conneting system welds to the first isolation valve were treated at that time.. Eighteen welds have not been treated and are scheduled to be worked on during the first refueling outage.
These welds and other susceptible welds out to the second isolation valve will receive IHSI treatment or last pass heat sink welding.
Ultrasonic inspection will follow all weld treatments.
IHSI or.last pass heat sink welding will be done on all susceptible welds in linit 1.during its first refueling outage.
This treatment will cover the recirc system and branch connecting systems out to the second isolation valve.
Ultrasonic testing of all treated welds will be performed.
Susceptible welds are considered to be those that have not been solution annealed, are made with IGSCC sensitive material, have a normal temperature above 2000F, and have not been treated by IHSI.
Present schedules list Unit I refueling to start during the Fall of'1985, and Unit 2 for the beginning of 1986.
u
-b 7
- H. R. Denton June 4, 1984 Item 2:
a) After the end of the Unit 1 refueling outage all welds would have been treated and examined, thus no susceptible welds would remain and this item would not apply to LaSalle.
b) No cracked welds have been found at LaSalle to date.
c) No weld overlays to mitigate cracking have been done at LaSalle.
d) All IHSI treated welds have received UT examination.
e) In the event of discovery of any cracking, LaSalle would comply with IEB 83-02.
Item 3:'All level 2 and level 3 UT examiners will have demonstrated competence in accordance with IEB 83-02 and level 1 examiners will have demonstrated field performance capability.
We contract for examiners and therefore availability is dependent on industry demand.
Ite:n 4: An extensive containment leakage system has been installed at LaSalle.
It consists of particulate and noble gas monitors, humidity, hydrogen, and oxygen analyzers,d pump down rate and level indication.ps with drywell floor drain and equipment sum fill-up~an Based on the age of the plant and the IGSCC mitigition efforts, it is felt that present tech spec limits adaquately monitor leakage and need no revision.
Item 5: We concur with the requirements of Attachment 2 for crack evaluation and repair criteria.
However, we take exception with Item 2(b) (1) and (ii) requirement to dye-penetrant test the first weld layer and not take credit for it in the repair.
It is our opinion that it is difficult to clean the dye-penetrant from the weld, cleaning unnecessarily.
increases man-rem exposure, and the residual dye-penetrant left may cause a defect.
In lieu of this we assure that the first layer'is an-effective crack barrier-by;
- 1.
Actually measuring that the delta ferrite content is greater than 7.5 Ferrite Number.
f o
H. R. Denton June 4, 1984 3
2.
Enhanced visual examination for cracks, lack of fusion and any evidence of flaw being continued in first layer.
3.
All welding is video taped.
The tapes are reviewed for evidence of flaws in first layer.
It is our opinion that this is a more effective program than the dye-penetrant.
All weld overlays have a minimum of two weld layers including the first layer.
To the best of my knowledge and belief the statements contained herein are true and correct.
In some respects these statements are not based on my personal knowledge but upon information furnished by other Commonwealth Edison and contractor employees.
Such information has been reviewed-in accordance with Company practice and I believe it to be reliable.
If you have any questions regarding this matter, please contact this office.
One signed ori provided for your use. ginal and forty (40) copies of this letter are Very-truly yours,
- Vf, C$Y B. Ryba Nuclear Licensing Administrator 1m cc
NRC Resident Inspector - LaSalle Dr. A. Bournia l-SUBSCRIBEb AND. SWO N to befo 3me this' day er
, 1984
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iotfry Pub;.ic o1-8728N'
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