ML20045E676
| ML20045E676 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 06/25/1993 |
| From: | Fenech R TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9307020303 | |
| Download: ML20045E676 (2) | |
Text
-
a.,.
t
't
-~
.?
j 6
k
. ~..
.. _. _ ~. _. ~,,....
.y..-,.%
s
-4..
,_.m..
am.-
.m Tennessee Vaaey Authtv4 Post O'f:ce Box 2000 Soday Damy. Tennessee 37379 2000 i
)
l Robert A. Fenech
'f vee Prescent sequoyan t4uclear Plant i
June 25, 1993 t
U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 l
-t Gentlemen:
l In the Matter of
)
Docket Nos. 50-327 i
Tennessee Valley Authority
)
50-328 i
SEQUDYAH NUCLEAR PLANT (SQN) - UNITS 1 AND 2 PRELIMINARY ACCIDENT t
SEQUENCE PRECURSOR (ASP) ANALYSIS t
Reference:
NRC letter to TVA dated June 10, 1993, " Preliminary Accident Sequence Precursor (ASP) Analysis-for Sequoyah Nuclear Plant l
Units 1 and 2" The purpose of this letter is to provide comments in accordance with the j
above reference. The following comments are separated by event and page j
number.
-}
l Ser,11on B.18. Licensge Event _Aepor.t (LER) No. 327/92-027.
j Page B-315, Section B18.1 Summary: This event did not occur as a result l
of a loss of offsite power. The breaker fault caused an undervoltage condition. This undervoltage condition caused the reactor. coolant pumps i
to trip, which caused each unit to trip.
S.ettion_B11L_LEJ1 No. 328/92-010 Page B-334,.Section B.19.4, Modeling Assumptions:
It appears that only-f two of the three cases that were run for this event are included in'this i
package. The conditional core damage frequency for having the diesel j
generator and residual heat removal pump failures for 17 hours1.967593e-4 days <br />0.00472 hours <br />2.810847e-5 weeks <br />6.4685e-6 months <br /> is shown on pages B-336 and B-338 as 2.0 E-6 +.2.6-E-7 = 2.3'E-6..
This is not the.
-l value given in Section B.19.5.
'i 020005 t
~
'9307020303 930625
- PDR.ADOCK 05000327
\\Q
'9.
von.
at j, -
I 6
L U.S. Nuclear Regulatory Commission Page 2 June 25, 1993 l
Additionally, the model allows no credit for_the safety injection pumps at SQN being available in addition to the centrifugal _ charging pumps for high-pressure injection. The exclusion of this modeling assumption from i
the ASP model will raise the core damage frequency for SQN.
Please direct questions concerning this issue to W. C. Ludwig at
[
(615) 843-7460.
Sincerely, 42/6' A
Robert A. Fenech cc:
Mr. D. E. LaBarge, Project Manager U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852-2739 NRC Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy-Daisy. Tennessee 37379-3624 Regional Administrator U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323-2711 I
l l
h
,