ML19343C336
| ML19343C336 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 10/18/1973 |
| From: | Hartley F CONNECTICUT YANKEE ATOMIC POWER CO. |
| To: | Anthony Giambusso US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| AO-73-09, AO-73-9, CYH-2486, NUDOCS 8103100260 | |
| Download: ML19343C336 (2) | |
Text
}atory File CyT
~
CONNECTICUT YANKEE AT O MIC POWER COMPANY
)F HADDAM NECK PLANT
/
- 1. BOX 127E EAST HAMPTON, CONN. 06424 October 18, 1973 CYH-2486
,( r %,
s$
rt>
/'0' #'k,(,.~(( 3
/ /A 50-213 Mr. A. Giambusso 07 Deputy Director for Reactor Projects
[~'
Q Directorate of Licensing i
p i
l ',',',b. k :Z i
U. S. Atomic Energy Comission U-g_; j Office of Regulation
\\j r
Washington, D. C.
20545 9y
, MD s
Dear Mr. Giambusse:
As defined by Technical Specifications for Connecticut Yankee Atomic Power Station, Section 5.3, the following incident involving an unsatis-factory test of timers associated with the emergency diesel generator / core cooling systems is hereby submitted as Abnormal Occurrence No. 73-9.
One phase of the routine monthly emergency diesel generator system test is to permit observation of the performance of the timing relays affecting operation of safeguards equipment. During the routine test of Emergency Diesel Generator 2A on 10/4/73, the timers that actuate both primary and backup service water pumps and contain ent air recirculation fans failed to operate as required.
Investigation revealed that two voltage sensing relay covers were tightened to the extent that the relay contacts could not function as required to actuate the service water pump timers and the containment air recirculation fan timers. These two voltage sensing relays had recently been inspected, cleaned and checked as part of a routine refueling interva! check of electrical relays and equipment. The two relay covers were loosened and adjusted to normal pressure. Additionally, the relay contact pressure was re-adjusted. All timers, including those associated with Emergency Diesel Generator 2B, were successfully retested.
The Plant Operations Review Comittee investigated the incident and concluded that the relay malfunction was caused by a combination of insuffi-cient relay contact pressure and over-tightened relay covers. There are six of these Westinghouse type-SV, General Purpose Relays in the diesel timer circuitry. The contacts in the two faulty relays will be replaced.
All six SV type relays will be inspected and tested at weekly intervals until the relays are either replaced with relays of improved design or the existing relays have demonstrated ecceptable reliability.
Instructions have been conspicuously posted in the diesel panel in the control room to alert personnel of the requirements for tightening the relay covers.
Additionally, supervisory personnel have been reminded of the importance
~~
of post-maintenance retest.
p
/
f r,.
- Ggsy )
8 c
~.
f'{0f/()64(sd Sh$
s
2-
-tober 18,1973 Mr. A. Giambusse-USAE With the accel'erated' surveillance program ar.d-increased awareness of retest requirements, it is not expected that this situation will recur.
Very truly yours, y
s
-[
A%
j /-F. W. Hartley Plant Superintendent RHG/mb.
4 i
j I
e f
i i
.--.4.--,.
,4--.
.c,....
._.,,,,.--,,_,,,.......,.,.y-,-,v..m,,-,,,,,,--
,-,,,,,,,,c.,,
-, -,...,,,.. _.., _, ~,.. _,,....,.
-