ML20096F490
| ML20096F490 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 08/14/1984 |
| From: | PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| RO-MM-3-02, RO-MM-3-2, NUDOCS 8409100068 | |
| Download: ML20096F490 (3) | |
Text
-
j
)
3 PHILADELPHIA ELECTRIC COMPANY l
1 2301 MARKET STREET P.O BOX 8699 PHILADELPHI A, PA.191o1 (215)841-4000 August 14, 1984 Docket No. 50-278
]
l Dr. Thomas E. Murley, Administrator Office of Inspection and Enforcement H
U.S. Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406
SUBJECT:
Peach Bottom Atomic Power Station - Unit 3 Moisture Monitoring System
Dear Dr. Murley:
This letter is a report of moisture monitoring system inoperability in accordance with Philadelphia Electric Company's commitment to report moisture monitoring system problems and alarms unrelated to actual system leakage as stated in letter, J. S.
Kemper, PECo, to Dr. T. E. Murley, USNRC, dated September-15, 1983.
Reference:
Docket No. 50-278 Report Number:
MM-3-02 Revision No.:
00 Event Date:
July 15, 1984 Report _Date:
August 14, 1984 Facility:
Peach Bottom Atomic Powe'r Station l
RD #1, Box 208, Delta, PA 17314 ABSTRACT l
On July 15, 1984, during Unit'3 startup operations, routine surveillance testing indicated three moisture sensors in the recirculation system moisture monitoring system were L
functioning improperly.
Hourly monitoring of the drywell sump
' pump out rates is being performed until the sensors can be replaced or repaired during the next outage of sufficient duration to carry out the work.
l I
B409100068 840814 DR ADOCK 050002 8
(
-EA1 f
Dr.' Thomas E. Murley August 14, 1984-Page 2 DESCRIPTION,OF,TH3, EVENT _
On July 15, 1984, during Unit 3 startup-operations, the moisture monitoring system display in the control room
-indicated a moisture alarm and a trouble alarm.
Investigation determined that the alarms originated from Points 1,'2 and 37.
Pointl is installed on weld 10-0-10-in the 20-inch residual heat removal system suction piping.
Point 2 is. installed on weld 10-0-7 in the 20-inch residual heat removal suction
. piping.
Point 37 is-installed on weld 10-B-2 in.the 20-inch
' residual heat removal system inlet piping.
Remote testing of the sensors at.these points indicated that the moisture alarm and trouble alarm.were triggered by the failure of the sensor.
'Following the identification of.the sensor failures,.the moisture monitoring system was-removed from service.
CONSEQUENCES OF THE EVENT Enhanced surveillance requirements (ST 13. 41, " Hourly Drywell Leak Detection") are being performed until an outage of sufficient duration to make the system operable.
The purpose of ST 13.41 is to provide,early warning of reactor coolant leakage via the drywell sump collection system when the moisture monitoring system is inoperable and reactor temperature is above 212 degrees.
These surveillance requirements ensure that drywell leakage rates do not exceed the limits of Technical Specification 3.6.C.l.
Therefore, the safety consequences of this event are considered minimal.
EAEEE gF,THg,3,qgI_
The cause of the event will be determined during the next unit outage of sufficient duration with the drywell deinerted.
[
CgRRECTIVE_ ACTIONS Hourly monitoring of the drywell sump collection system is being performed until the next unit outage of sufficient 4
duration with the drywell deinerted so that these sensors can be made' operable.
Additionally, the system is restored to I
operable status once per day to perform ST 13.40, " Checkout of
. Moisture Monitoring System", as an additional surveillance requirement, j
{ -
~
~:. :.
lDr. Thomas E. Murley August 14, 1984
-Page-3 l
1 PREVIOUS SIMILAR, OCCURRENCES LER 2-83-26/3L, 3-83-16/3L, 3-83-21/3L, 3-83-24/3L letter:
W.
T. Ullrich, PECo, to Dr. T. E. Murley, USNRC, dated March'5, 1984, letter:
W. 'r.
Ullrich, PECo, to Dr. T. E. Murley, USNRC,
' dated March 23, 1984, and letter, R. H. Logue, PECo, to Dr. T.
E. Murley, USNRC, dated July 23, 1984.
Very truly. nurs, A
Superinten ent Nuclear Services cc:
A. R. Blough, Site Inspector J. F. Stolz, Operating Reactors Branch #4 f
u