ML19340E443
| ML19340E443 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 01/08/1981 |
| From: | Delgeorge L COMMONWEALTH EDISON CO. |
| To: | Youngblood B Office of Nuclear Reactor Regulation |
| References | |
| 9498A, NUDOCS 8101140512 | |
| Download: ML19340E443 (5) | |
Text
.
Commonwealth Edison cne First National Ptaza. Chicago.11ncis Address Reply to: Post Office Box 767 Chicago. Ilknots 60690 January 8, 1981 Mr. B. J. Youngblood, Chief Licensing Branch No.1 Division of Licensing U.S. Nu clear Regulatory Commission Washington, DC 20555 Subj e ct :
LaSalle County Station Units 1 and 2 Supplemental Response to NRC Request For Information Concerning S/RV T-Quencher Frequen cy Range NRC Do cket Nos. 50-373/374 Reference (1):
L. O. DelGeorge letter to B. J. Youngblood dated November 3, 1980 l
Dear Mr. YoungDlood:
The purpose of this letter is to provide supplemental information in response to an inquiry from your staff on the I
frequency range over which the LaSalle County S/RV T-Quencher air clearing load assessment was made.
The information that is I
presented in the attachment was dis cussed with Messrs. Bournia, Su l
and Ho of the NRC in a telecon on November 20, lyd0.
If you should have any further questions in this regard, please direct them to j
this of fi ce.
t This dis cussion is responsive to the LaSalle County open issue ident'ified as No. 4( C)(a) in the list provided by Mr. Bournia in De cember, 1980.
Very truly yours, L. O. DelGeorge Nuclear Licensing Administrator g[
At t a chment cc:
NRC Resident Inspe ctor - LSCS I
9498A 8101140 & Q
Atta chment LaSalle All Valve Discharge Case Design Basis Frequency Range i
In oroer to demonstrate the adequacy of the LaSalle Station design basis frequency range for the all valve discharge case, a comparison was made between it and the frequency range provided in NUREGl0487, 4
Supplement No. 1 (September, 1980).
The comparison was accomplished by generating envelopes of the magnitude of the Fourier transforms of the sets of factored design traces produced by the two methods.
The LaSalle Station design basis is 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 is derived from using a 1.1 amplitude multiplier on the three KWU design traces and sweeping a dominant frequency range of 3 to 11 l
l hertz.
The resulting design envelopes are compared in the attached figure.
Note that the LaSalle design basis is 25% higher than the NRC design basis ex cept in the narrow frequency range of 11 to 13 H7; In this narrow range, the NRC design basis is, on the average l
8% higher.
l L
. In our judgment this small increase over a narrow frequency range is of no design significance.
Our opinion is based on the following:
A.
The total structural and piping response has contributions from several frequencies.
The LaSalle Design casis is 35% higher than the NRC design basis except in the 11-13 Hz range where it is 8% lower.
In our opinion any increase in structural or piping response due to a higher 11-13 Hz input will be more than compensated by a lower input (and response) for all other f requen cie s.
B.
The LaSalle design is based onthe simultaneous occurance of the SSE, LOCA and the SRV events.
As the combined design response has contribution from all three loads, the increase in the combined response would be a small fraction of the increases in the SRV responses.
Based on the combined ASME Service Level C response spectra at six selected locations in the containment-Reactor Building complex we have determined that 8%
increase in the SRV response spectra in the 11-13 Hz frequency range will result in a less than 0.8% increase for the vertical response spectra components and a less than 4% increase for the horizontal response spectra component s.
These small increases, coupled with the discussions presented in paragraph A above, make the small variations of the LaSalle SRV design specifications from the NRC SRV design specificatidn of no
_3_
design significance.
Baseo on the above discussion, it can be concluoed that the LaSalle SRV load specification meet or ex ceed the intent of the NRC requirements as Contained in NUREG-0487, Supplement 1.
9498A
..........................-........IlU.S.go o
....s
........... CO M PA RI SON OF.LAS ALLE DESIGN B ASIS AND I
....._...... MUREG-093'l SU PPLEVdN T i 3
6 i
o
-. w
-__.u----.....-..
.u i
i w
. _i._.:.. -
....... _.. v>
m
....2_._.i._._
t..
a.
l v
e
=_-_
. i....:..,....i......i w
4
.._.a..._.
i
....o
.o f--
i
!l l
i
..:..i..:..'. :...!
i i
i I
i r
..;..d..'__....:.
[
I.... I
. _ _ ' _. [t [dSEI.LE DESlGN BAS!S g
l
~
.. ;. :. r.i. ;_.. l e
....:. i..
7 g
j s
i
.l..l.,. }
2
.(
.. s.
- 1...i.l o
. u. -
NUR1EG -Ou. S7.
i
\\
.i s
s O
5 to.
15 20 f i g C T... %)
- r..r *,. P ' V s il n wo
..wi g
M ' F~D)Y i'
D ChbN S
.