ML20076L518
| ML20076L518 | |
| Person / Time | |
|---|---|
| Site: | Catawba  |
| Issue date: | 07/11/1983 |
| From: | Tucker H DUKE POWER CO. |
| To: | Adensam E, Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8307190218 | |
| Download: ML20076L518 (5) | |
Text
.
Duxu Powen GOMPANY P.O. HOx 33180 CHAMLOTTE. N.C. 28242 IIAL II. TUCKEH TELEPHONE vna ressament -
(704) OT}4031 mm. -
=m.
July ll, 1983 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Attention:
Ms. E. G. Adensam, Chief Licensing Branch No. 4 Re: Catawba Nuclear Station Docket Nos. 50-413 and 50-414
Dear Mr. Denton:
Section 8.4.7 of the Catawba Safety Evaluation Report discusses Confirmatory
. Item 36, Flooding of Electrical Equipment as a Result of a LOCA.
In response to this item, please find attached a revised response to FSAR question 440.48.
Very truly yours,
<g b(
x w Hal B. Tucker
.s ROS/php Attachment cc:
Mr. James P. O'Reilly, Regional Administrator U
S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30303 NRC Resident Inspector Catawba Nuclear Station Mr. Robert Guild, Esq.
Attorney-at-Law P. O. Box 12097 Charleston, South Carolina 29412 Palmetto Alliance 2135 Devine Street Columbia, South Carolina 29205 8307190218 830711
{DRADOCK05000 h/
///.
__.___m_
Mr. Harold R.~Denton, Director July.ll, 1983-Page 2 cc:
Mr. Jesse L. Riley Carolina Environmental Study _ Group' 854 Henley Place Charlotte, North Carolina 28207 Mr.. Henry A. Presler,-Chairman Charlotte-Nhcklenburg Environmental Coalition 943 Henley Place Charlotte, North Carolina 28207
CNS Mo. V8
Response
The maximum post-accident flood level inside containment has been determined to be elevation 570'0".
The only safety related control
' room instrumentation below this elevation are the reactor coolant loop elbow flow rate instruments.
This instrumentation provides both control room indication and a reactor trip (on low flow in any one loop) neither of which is required after an accident (no operator actions taken on indication, and reactor trips due to safety injec-tion signal).
A list of safety related solenoid valves in containment that are be-low maximum flood elevation is presented in Table Q440.48-1.
These solenoids perform one of two functions; namely, controlling air to air diaphragm operated valves and providing air to the lower personnel air lock inflatable seals.
All of the air diaphragm operated valves are designed to assume their safety position on loss of air.
All of the solenoids controlling the air supply are designed to vent the air diaphragm on loss of power.
Therefore, even if control of these solenoid valves is-lost the air operated valve will assume its correct position.
The solenoids which supply air to the lower personnel air lock seals are designed to fail in the position which supplies air to the seals.
None of these valves are required to be repositioned to perform short or long term ECCS functions.
A list of active valves in containment that are below maximum flood elevation is presented in Table Q440.48-2.
In this evaluation it was discovered that two valves were required to be raised above flood elevation (the two valves -- INW46A and 1NW1108 provided sealing water for several containment isolation valves).
The valves which will potentially be flooded are, except as noted, electric motor operated.
These are assumed to fail in the position they are in when flooded.
There is sufficient time for the ones which receive a safety signal to stroke to their safety positions before being flooded.
None of these valves are required to be repositioned to perform short or long term ECCS functions.
In addition, 18 valve operators were not previously qualified for submergence (1KC4298, INC54A, INI95A, 1NI266A, 1NI267A, INM6A, 1NM72B, 1NM758, INM788, 1NM818, INH 187A, INM190A,-INM1978, INM200B, INH 207A, INM210A, INM2178, and INH 2208).
These valves close on Containment Isolation Phase A (ST) signals.
There is sufficient time for them to close before being flooded.
To prevent possible repositioning after flooding, the valves motor con-
.trols circuits are being modified (see Fig. Q440.48-1).
One relay per train will be energized by a ST signal and mechanically latched in.
Normally closed contacts from this relay will be wired between the limit switches and the open motor starter coils of valves of the corresponding train.
These contacts will open on ST and prevent any spurious limit switch operation from repositioning the valves.
These-i relays will have manual reset capability in the control room.
i 440-45a Rev. 8
Breakers and fuses are coordinated such that, in the case of faults caused by submergence, the faulted valve circuits will be isolated without adversely affecting the upstream class IE power sources.
These modifications will be completed prior to fuel loading.
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