ML20079G538
| ML20079G538 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 09/30/1991 |
| From: | Joshua Wilson TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9110090150 | |
| Download: ML20079G538 (3) | |
Text
___
i A
Jr. i W.
September 30, 1991 U.S. Nuclear Regulatory Conmisalon ATTN:
Document Cent rol Desk Washington, D.C.
20555 Gentlemen:
In the Matter of
)
Docket Nos. 50-327 Tenriessee Valley Authority
)
50-329 SEQt'0YAH NUCLEAR PLANT (SQN) - REVISED COMPLETION DATE FOR ESSENT' AL RAW COOLING WATER (ERtW) TFMPERATURE r0NTRCL VALVE REPLACEMENT C05S1!TMENT FCK THr MAIN CONTkOL h00M (MCR) AND ELECTRICAL BOARD ROOM (EBR ) AIR CONDITIONERS - INbPECTION REPORT NOS. 50-327, 328/87-73
References:
1.
TVA letter to NRC dated March 29, 1491, "Sequoyah Nuclear Plant (SQN) - Revised Completion Date for Essential Raw Cooling Water (ERCW) Temperature Contral Valve Replacement Commitment - NRC Inspection Report No. 50-327, 328/87-73" 2.
7VA letter to NRC dated September 25, l ') 8 4, "Sequoyah Suelear Plant (SQN) - NRC Inspection Report Nos. 50-327/87-73 and 50-328/S7 Suppl-: mental Response" The commitment completion date for replacing the ERCW temperature control valves for the MCR and EPR chiller packages was June 3, 1991, by Reference 1.
Since Reference 1 was submitted, the installation of components needed to implement the modification to tre subject temperature control valves has been completed under Design Change Notice M03h42A. However, during the testing af the control system after the associated condenser had been out of service for an extended period of time, the valves would not open within sufficient time to allow the ref rigerant nachine to continue to operate before tripping on high head pressure.
This is attributed to a reset mechanism in the controller and a phenomenon known as reset " wind-up."
A new pneumatic controller with 91g0090150 910930
}h ADOCK0500f,y7 gg PDR O
._-...____...._..___.-~._....._...___..___..._.__._.._..__.__m j
a l
k i
4 2
U.S. Nuclear Augulatory Consnission c
September 30, 1991 i
reset capability and an anti-remet wind-up feature has been purchased for i
one temperature control valvo, and a ffold test was completed on September 20, 1991.
Based on successful completion of the test, the schedule for the procurement, qualification, and installation of the controllers is April 3, 1992.
If you have.sny questions concerning this submittal, please telephone M. A. Cooper at (615) % 3-5422.
Sincerely, l
$ r1'L J
L. Wilson Enclosure ec.(Enclosure):
Mr. D. E. LaBarge, Project Manager U.S. Nuclear Regulatory Commi.sion One White Flint, North 11555'Rockville Pike Rockville, Maryland 20B52 NRC Reutdent inspector Sequovah Nuclear Plant 2600 Igou Forry Road Soddy-Daisy, Tennessee 37379 Mr. 3. A. Wilson, Project Chief U.S.. Nuclear _ Regulatory Commission j
= Region.II 101 Marietta Street.-N% Suite 2900 Atlanta, Georgia 30323 9
l l-l
~
L
... -.... ~..
~. -.. -
.. ~.--.. ~.. _..-~. -
,, +
ENCIMURE Conuni tmen t The ma!n control room and electrical board room chiller package enentini raw cooling water. temperature control valves will be modifled to ptovide reliable automatic operation by-Aprli 3, 1992.
PLO90204/122 i
i 1
l 1
I l
i 1
l r
s f
- W"
w-
'--a4 1a,e r w w e eww w en -a m-wmwww Q,,ve.-w-
,.pm-.yp. y4 m
,,ngg.
,_,,g, 4.,
,g.
,