ML20084S331
| ML20084S331 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 08/01/1975 |
| From: | Kalivianakis N COMMONWEALTH EDISON CO. |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20084S335 | List: |
| References | |
| AO-50-254-75-18, NJK-75-392, NUDOCS 8306160688 | |
| Download: ML20084S331 (2) | |
Text
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Com r.ith Edison s
Quad ensrating Stati:n j
Pcst Offi 216 Cordova,I!!inois 61242 Telephone 309/654-2241
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NJK-75-392 p_
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August 1, 1975
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Director of Office of Nuclear P.eactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C.
20555
Reference:
Quad-Cities Nuclear Power Station Docket No. 50-254, DPR-29, Unit 1 Appendix A, Sections 1.0.4.2, 3.7.A.3.a, 6.6.B.1.a Enclosed please find Abnormal Occurrence Report No. A0-50-254/75-18 for Quad-Cities Nuclear Power Station. This occurrence was previously reported to Region lil, Directorate of Regulatory ' Operations by telephone on July 25, 1975 and to you and Region lil, Directorate of Regulatory Operations by telecopy on July 28, 1975 This report is submitted to you in accordance with the requirements of Technical Specification 6.6.B.I.a.
Very truly yours, COMMONWEALTH EDISON COMPANY QUAD-CITICS NUCLEAR POWER STATION r
c bb.,e~ 9 N.J. Kal ivianakis u
Station Superintendent NJ K/RAR/vmb
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Region lil, Directorate of Regulocory Operations J.S. Abel
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~ REPORT. NUMBER: A0-50-254/75-18
. REPORT DATE: August 1, 1975 0CCURRENCE DATE: July 24, 1975 FACILITY: Quad Cities Nuclear Power Station Cordova,. Illinois 61242 IDENTIFICATION OF' OCCURRENCE:
Satpoint drift of reactor building to suppression chamber vacuum breaker pressure sensor r
2-16228.
L CONDITIONS PRIOR TO OCCURRENCE:
The-unit was in the RUN mode with 2002 MWt and 630 MW.
e DESCRIPTION OF OCCURRENCE:
-OnJuly2h,1975,at3:00PM, the Instrument Maintenance Department was doing routine
~
quarterly surveillance calibration of the pressure suppression chamber to reactor
~ building vacuum breaker pressure switches when it was discovered that one of the switches tripped at a value in excess of the Technical Specification limit.
Pressure switch PS-1-16228 tripped at-0.5126 psi while the limit is 0 5 psi.
No operator actions were required to bring the situation under control.
DESIGNATION OF APPARENT CAUSE OF OCCURRENCE:
/The apparent cause of this occurrence is designated as instrument drift.
No other cause cculd be determined from-an Inspection of the switch and from the recalibration process.
ANALYSIS OF OCCURRENCE:
PS-1-16220 operates vacuum breaker 1-1601-208.
Because of the increase-in the trippoint, the vacuum'in the pressure suppression' chamber would have had to increase to 0.5126 psi bnfore the. vacuum breaker would have opened.
However, the redundant switch, which operates thc 1-1601-20A vacuum breaker, was within limits; thus, its vacuum breaker would have
. cptned before the vacuum in the suppression chamber reached the limit.
Consequently the safety implications arising from this occurrence are minimal.
In no way was the integrity of the suppression chamber threatened nor were the public health and safety endangered.
CORR'ECTIVE ACTION:
The pressure. switch was recalibrated.
No further action I
~ lanned at this time.
p FAILURE DATA:
This was the first occurrence.of.this type, thus no safety implications related to cumu-lative experience exist.
EQUIPMENT IDENTIFICATION:
H nufacturer Statis "0" Ring Modal.
12R2kk815-V-
' Rings '
+ 20 psi 7,.
-