ML20213G125
| ML20213G125 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 11/07/1986 |
| From: | Agosti F DETROIT EDISON CO. |
| To: | Adensam E Office of Nuclear Reactor Regulation |
| References | |
| VP-86-0154, VP-86-154, NUDOCS 8611170335 | |
| Download: ML20213G125 (2) | |
Text
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1 I/c7e$s@i" suci r oper.t.on.
DOITOil r.<, i a Edison E5BFN ta.
November 7, 1986 j
VP-86-0154 Office of Nuclear-Reactor Regulation Ms. Elinor G. Adensam, Director Project Directorate No. 3 i
Division of BWR Licensing U. S. Nuclear Regulatory Commission Washington, D. C. 20555
Dear Ms. Adensam:
Reference:
1)
Fermi 2 NRC Docket No. 50-341 l
NRC License No. NPF-43 2)
Detroit Edison to NRC Letter, " Service Life of Main Steam Bypass Line",
l VP-86-0146, dated October 16, 1986
Subject:
Service Life of Main Steam Byoans Line Reference 2 described the preliminary evaluations of the new i
main steam bypass piping performed by Hopper and Associates and j
by Stone and Webster (S&W).
Hopper's final results indicate the lines are acceptable if cumulative operation with bypass valve position between 30% and 45% opened does not exceed 100 days.
l Based on this evaluation, the new piping has a service life I
which will allow it to remain in service for the life of the plant under anticipated operating conditions.
The continued i
serviceability of the bypass piping will be validated. further by performing Nondestructive Examination (NDE) of the seam weld in the 30 inch piping from the west bypass valve to the first orifice plate in that line during the first refueling outage.
While the Hopper analysis indicated that the piping was acceptable for its expected service life, the analysis provided by S&W using different calculation methodology did not support this conclusion.
S&W indicated that additional testing would
{.
allow them to refine their calculations, possibly resulting in i
less restrictive operating constraints for the bypass lines.
This additional testing has been performed, and S&W was able to reduce the equivalent stress frequency to 8.2 Hz and to replace i
a conservatively assumed stress index with a more realistic 1
value of 2.66.
As a result, S&W has concluded that the bypass lines are acceptable for operation within the constraints previously provided by Hopper.
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o Ms. Elinor G. Adensam November 7, 1986 VP-86-0154 Page 2 As committed in Reference 2, Detroit Edison will maintain a i
record of the cumulative time the lines are operated with the bypass valves between 30% and 45% opened.
This time will be reported annually, and will not exceed a cumulative value of 100 days without prior notice.
If you have any questions on this matter, please contact Mr. Joseph Conen, (313) 586-4275.
Sincerely, N 8 cc:
Mr. J. J. Stefano Mr. W. G. Rogers USNRC Document Control Desk Washington, D. C. 20555 i
l I
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