ML19339A683
| ML19339A683 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 10/28/1980 |
| From: | Delgeorge L COMMONWEALTH EDISON CO. |
| To: | Youngblood B Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8011040524 | |
| Download: ML19339A683 (3) | |
Text
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Commonwealth Edison one First National Plaza. Chicago, !!!inois Addre2s Reply to: Past Office Box 767 Chicago, Illinois 60690 October 28, 1980 Mr. B. J. Youngblood, Chief Licensing Branch No. 1 Division of Licensing U.S. Nuclear Regulatory Commission Washington, DC 20555
Subject:
LaSalle County Station Units 1 and 2 Response to INFORMAL Request for Information Concerning S/RV T-Quencher Frequency Range NRC Docket Nos. 50-373/374
Dear Mr. Youngblood:
The purpose of this submittal is to respond to an informal inquiry from your staff (Messrs.
A. Bournia and F. Eltawila) concerning the frequency range over which the LaSalle County S/RV T-Quencher air clearing load assessment was made.
This issue is an outgrowth of discussions on Section II.8.5 of Supplement 1 of NUREG-0487, " Mark II Lead Plant Acceptance Criteria".
Our specific comments in this regard are documented in the attachment to this letter.
We provide therein the basis upon which, for LaSalle County Units 1 and 2, the range of 3.4-10Hz was derived and demonstrated to be conservative.
If you have any further questions in this regard, please direct them to this office.
Very truly yours, j'r 1
9
- . r,a.xf u L. O. DelGeorge Nuclear Licensing Administrator Attachment cc:
RIII Resident Inspector - LSCS 8011040Mf 7745A
F Attachment LaSalle All Valve Discharge Case Design Basis Frequency Range As stated in the LaSalle County Station Design Assessment Report, Chapter 3.2, the Safety / Relief Valve (S/RV) discharge load definition used for assessment of the T-quencher is entirely consistent with the methods described in the Susquehanna Steam Electric Station (SSES) Design Assessment Report, Chapter 4.
These methods have been demonstrated to be conservative by full scale tests performed by KWU at the Karlstein test facility and reported in the SSES, DAR, Chapter 9.
In our judgment the S/RV discharge load definition methods referenced in the preceeding sentences, provice a complete and conservative basis for plant design.
In order to further demonstrate the adequacy of the LaSalle Station design basis frequency range for the all valve discharge case, a comparison has been made between it and the frequency range provided in NUREG-0487, Supplement No. 1 (September, 1380).
The comparison has been accomplished by generating envelopes of the magni.ude of the Fourier transforms of the sets of factored design traces produced by the two methods.
The LaSalle station design basis envelopes 19 traces which were derived from using a 1.5 amplitude multiplier on the three KWU design traces and sweeping a dominant frequency range of 2.9 to 9.9 hertz.
The NRC design basis envelopes 12 traces which were derived from using a 1.1 amplitude multiplier on the three KWU design traces and sweeping a dominant j
frequency range of 3 to 11 hertz.
The resulting design envelopes are compared in the attached figure.
The LaSalle station design l
basis is bounding for essentially the entire specified range of 3 to i
11 hertz.
l The small region where the LaSalle station design basis is not bounding is judged to be insignificant.
This judgment is based on the conservative method used to apply the design basis traces i
described above.
Each of the response spectra which are computed for the 19 scaled design traces are broadened about 15% to account for uncertainties.
This technique provides additional margin in plant design.
Further, LaSalle in-plant S/RV discharge tests will De used to confirm cath the design S/RV loao amplitude and the S/RV frequency range for first and subsequent actuations.
Based on this comparison and the above discussion, it is concludeo that the LaSalle station design basis frequency range for the all valve discharge case is in compliance with the requirements of NUREG-0487, Supplement NC 1.
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