ML20012D744
| ML20012D744 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 03/16/1990 |
| From: | Schnell D UNION ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| REF-GTECI-A-47, REF-GTECI-SY, RTR-NUREG-0830, RTR-NUREG-1217, RTR-NUREG-1218, RTR-NUREG-830, TASK-A-47, TASK-OR GL-89-19, ULNRC-2177, NUDOCS 9003280318 | |
| Download: ML20012D744 (6) | |
Text
'
1901 Gratht strut l'ost offte Bu l49
. St Louis. Missouri 63166 -
314-554-2650
(
L u
1
- "*u r. schneu UNION Etscru.i.55
~~ ' u= "*" c c March 16, 1990 th*ar 2
U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail-Stetion P1-137
' Washington, D.C.
20555 ULNRC-2177 i
Gentlemen DOCKET NUMBER.50-483 CALLAWAY PLANT SAFETY IMPLICATION OF CONTROL SYSTEMS IN LWR EUCLEAR POWER PLANTS
Reference:
Generic Letter 89-19 dated September 20, 1989 Generic Letter 89-19 documented NRC resolution i
of Unresolved Safety Issue (USI) A-47, " Safety.
Implications of Control Systems in LWR Nuclear Power Plants".
This resolution is based on NUREG 1217,
" Evaluation of Safety Implications of' Control Systems in LWR Nuclear Power Plants" and NUREG-1218, " Regulatory
. Analysis for Resolution of USI A-47".
NRC has. concluded that all PW3 plants should provide automatic steam-generator (S/G)-overfill protection and that plant procedures and technical specifications should include provisions to periodically verify the operability of the overfill protection system.
The S/G overfill protection for Callaway Plant satisfies-the requirements of Item 2(a) of Generic Letter 89-19, Enclosure'2.
The S/G overfill protection system is based on a 2-out-of-4 safety grade initiating logic, thus making Callaway a Group 1 plant.
Upon-sensing high level in any S/G, the system isolates Main Feedwater flow to_all S/G's by closing the Main Feedwater Isolation Valves (MFIV), the Main Feedwater Centrol Valves, the Main Feedwater Control Bypass Valves, and by tripping the turbine-driven Main Feedwater' Pumps which closes the associated pump discharge valves.
This circuitry is depicted on FSAR Figure 7.2-1, Sheets 7, 13, 14 and meets the separation l
criteria described in FSAR Section 7.1.2.2.1.
NRC has previously evaluated the Callaway separation criteria and S/G overfill protection system in support of NUREG-0830, " Safety Evaluation Report Related to the 9003280318 900316 h)
O PDR ADOCK 05000483
!(
P.
PDC y
{
\\g
E VL E
1",
Sections Operation of Callaway Plant, Unit No.
7.2.2.7 and 7.3.2.8.
NUREG-0830, Supplement 3,.Section 7.3.2.8 documents NRC site visits which confirmed the existence of this circuitry.
With the exception of the Main Feed Pump Turbine trip solenoids, as discussed below, the entire S/G overfill protection system is safety-related.
Redundant circuitry ensures that a failure of a single active component will not prevent completion of the protection functions (closure of the MFIV's and the Feedwater Control and Bypass Valves).
Loss of power will also close the MFIV's and the Feedwater Control and Bypass Valves.
Even though the Main Feedwater Pump Turbine trip signals are generated by the same safety grade system as the remainder of the S/G overfill protection system, the trip solenoids which accomplish the trip function (and the trip solenold's power source) are non-safety grade and must be energized to trip the turbine.
Therefore, a loss of power will not result in a direct Main Feedwater Pump trip.
This has little consequence relative to S/G overfill protection because, as discussed above, a safety grade high-high S/G level signal or loss of power will result in closure of the MFIV's and Feedwater Control and Bypass Valves (which are in series, effectively isolating feedwater flow to the steam generators).
The control portion of the S/G level control system is completely separated, both physically and electrically, from the S/G overfill protection system.
The S/G level control system inputs from the level transmitters are isolated via loop power supply cards from the safety grade portion of the system that generates the S/G overfill protection signals.
The power source which supplies the level control equipment t
is different than the power source which supplies the overfill protection system.
In addition, the cabinets which house the level control equipment are physically separated from the cabinets which house the overfill protection system.
Therefore, a fire in the level control circuitry will not cause a failure of the overfill protection system to perform its intended function.
i Callaway Technical Specification Table 3.3-3, Functional Unit 5.b, requires the subject circuitry be operable in Modes 1 and 2 and Table 4.3-2, Functional Unit 5.b.
specifies the appropriate surveillance requirements and frequencies.
Plant procedures assure these requirements are met.
j 3.-
4.
L
~*
Based upon the above, Callaway is a plant that already provides a satisfactory design for overfill protection and also has-Technical. Specifications dealing with the overfill protection system which were previously approved by the Staff.
Therefore, no changes or implementation schedule need be provided in response to this generic letter.
If there are any questions with regard to this, please contact me.
Very truly yours, j
/
C appcub---
Donald F.
Schnell DFS/dla 1
4
/
M 34
?
s J.^
L d
- STATE OF MISSOURI )
)
y i
Alan C.
Passwater, of lawful age, being first dul'/ sworn upon oath says that he is Manager, Licensing and Fuels (Nuclear) for Union Electric Company; that he has read the foregoing document and knows the content thereof; that he has_ executed the same for and on behalf of said company with full power and authority to de so; and that the facts therein stated are true and correct to thr best of his knowledge, information and belief, n
By
/
~ '
Alan C.
Passwater Manager, Licensing and Fuels-Nuclear
.SUBSJC IBED and sworn to before me this
/S7 IA'
-- day of //u421
- 1990, e
N
- c.,,s.;..i#3. er n.# f [
N01 ARY PUBLIC. STATE OF MISSOURI MY COMMISSION EXPIRES APRIL 22, 1993 g.
ST. LOUIS COUNTY
)
~p :
ces-_ Gerald Charnoff, Esq.
Shaw, Pittman, Potts & Trowbridge 2300 N.
Street, N.W.
{
Washington, D.C.
20037 Dr.
J..O.
Cermak-CFA, Inc.
4-Professional Drive (Suite 110)
Gaithersburg, MD 20879 t
R.
C.
Knop l
Chief, Reactor Project Branch 1 U.S.
Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn,. Illinois'60137 Bruce Little Callaway Resident. Office U.S.
Nuclear Regulatory Commission RRM1 Steedman, Missouri 65077 S. V. Athavale.(2)
Office of Nuclear Reactor Regulation U.S, Nuclear Regulatory Commission 1 White Flint, North, Mail Stop 13E21 11555 Rockville Pike Rockville, MD 20852 Manager, Electric Department Missouri Public Service Commission P.O.
Box 360 Jefferson City, MO 65102 i
t i
t L
bec: D. Shafer/A160.761
/QA Record (CA-758)
Nuclear Date E210.01 5
DFS/ Chrono.
D.
F.
Schnell J. E.
Birk J. V.
Laux M. A.
Stiller G.
L. Randolph R. J.
Irwin H. Wuertenbaecher W. R. Campbell A. C.
Passwater R. P. Wendling D. E.
Shafer D. J. Walker O. Maynard (WCNOC)-
l N. P. Goel (Bechtel)
T. P.
Sharkey NSRB (Sandra Auston) poo,412 ( M-t 4)
G.b. f
- h. T. WJAn^
T i
l l
i '
I P
r
,