ML20084F323
| ML20084F323 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 12/28/1972 |
| From: | Worden W COMMONWEALTH EDISON CO. |
| To: | Anthony Giambusso US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20084F301 | List: |
| References | |
| 67, NUDOCS 8304210098 | |
| Download: ML20084F323 (2) | |
Text
p..
v v
2
--m l
50-237 Commomvealth Edison Company J/ h 72 WEST ADAMS STREE7
- CHICAGO. ILLINOls
'Y(h
,m.., n.s, e.,
te.,
1 on o,, ice oxr.7
- c,o c 4 o o. i s t i n o i s.....
n y
kWO
}
Dresden Nuc1 car Power Station
'1 R. R. #1
,,;,.(,y.y g
/
Morris, Illinois (,0450 y)g\\,s -
y;,,
Vs. s 9,,gk December 28, 1972 f.
4
~
'D h, g:hy, g{f,q.'gl Re~gulatory g"ilo Cy[,
C3, Mr. A. Ciambusso 4
f g'{
],[, y Deputy Director for Reac.cor Projects Directorate of Licensing
.g U. S. Atomic Energy Commission Ij,e y,
Washington, D.C.
20545 gy
Subject:
License DPR-19, Dresden Nuclear Power Station, Unit #2, Section 6.6.C.1 of the Technical Specifications
Dear Mr. Giambusso:
This is to report a condition relating to the unit in which, on December 1,1972, HPCI valve MO-2-2301-4 failed to open when given an open signal from the control room.
PROBLEM AND INVESTIGATION On December 1,1972, the packing gland for HPCI valve #MO-2-2301-3 was adjusted to stop a small steam leak.
After adjusting the gland, the HPCI system was valved out to permit post-maintenance testing of the MO-2-2301-3 valve.
The valving out procedure included closing the M0-2-2301-4 and MO-2-2301-5 valves. After the MO-2-2301-3 test, the MO-2-2301-5 valve was opened but the MO-2-2301-4 valve would not open when given an open signal from the control room. The maintenance department immediately opened valve MO-2-2301-4 by holding in the motor contactor. Normal motor current was observed during the opening cycle, which indicated that no problems existed in the valve mechanical mechanism.
1 Investigation into the cause of the valve failure revealed that a relay coil on an interlock device had burned open.
The defective relay is identified as #902-3-2330-153. The relay function is to require the HPCI 2301-5 valve to be open before the HPCI 2301-4 valve can be opened.
The coil failure prevented this permissive function, thereby rendering normal control inoperable.
l 1he cause of the relay coil failure was component misapplication.
'Ihe burned open coil was rated at 125 volts D.C. and was being used in a 250 volt D.C. circuit.
8304210098 730214 PDR ADOCK 05000237 S
PDR e'
o O
- -. L l
W Mr. A. Giambusso December 28, 1972 Although the HPCI HO-2-2301-4 valve would not open by a signal from the control room, the valve would have opened automatically on reactor low water level.
This feature kept the HPCI System operable during the entire testing procedure for valve HO-2-2301-3 and also allowed auto operation even though the #903-3-2330-153 coil burned open.
_ CORRECTIVE ACTION The burned open coil was immediately replaced, and series resistance added to the circuit to prevent another burnout.
A permanent solution to the problem is to replace the relay coil with one of the proper voltage (250 volta A.C.).
The replacement coil has been ordered. Also,since the same condition exists on the Dresden Unit #3 HPCI system, similar corrections will be made to that circuit.
kuck N. $eww y
W. P. Worden kd/' Superintendent WPW:sdb
.2
~
'W*