ML20084F248
| ML20084F248 | |
| Person / Time | |
|---|---|
| Site: | Dresden, 05002377  |
| Issue date: | 01/15/1973 |
| From: | Worden W COMMONWEALTH EDISON CO. |
| To: | Anthony Giambusso US ATOMIC ENERGY COMMISSION (AEC) |
| References | |
| 41-73, 522, RP-730115, NUDOCS 8304210051 | |
| Download: ML20084F248 (2) | |
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,4 50-237 Commonwealth Edison Company x
72 WEST A D A MtB STREET CHICAGO.
ILLINOIS aa,... n.,a o..
r POST OFFICE toX 767
s WPW LTR. #41-73 January 15, 1073
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l'r. A. Giamhunoo C
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Deputy Director for Reactor Projects koi C
Directorate of Licensinc Q
U. S. Atomic Fnerry Cornissicn Q'/gT,A ; J.
Wachington, D. C.
20545
SUBJECT:
LTCIQE DPR-11 D3?3DFN NpCLFAR POWER _ STATIO:1,, UNIT #2 SECTIO: 6.6.B.2 OF THF TECP:IC AL SPFCTFICATIOUS.
Dear Mr. Giambusso:
This is to report a conditien relatine to the Unit in which, on January P,1973, the switches for the High Pressure Coolant Injection System (HPCI) hirh flew isolstion drifted above the Technical Epecification limit of a differential pressure of S 150 inches of water. The switches were immediately recalibrated to comply with the Technical Specification Limits.
PROBTR M D MVESTIGATIO:!
The switches are Barton Mcdel # 288 differential pressure sensors identified as DPIS 2-2352 and DPIS 2-2353. The hictory of these switches shows drift in both the increasing and decreasing directien. This drift problem has been investicated and the manufacturer's sugrested correction is to inctall lockinF devices en the calibrating screws to prevent screw move-ment caused by normal plant vibraticn. The locking devices have been ordered and are presently beine processed thrcuch Cerronwealth Edisen Cuality Assurance. The devices will be installed as soon as practical en all Barton Mcdel #2F8 switches, with an estimated completion date of March 1,1973.
The function of DPIS 2-2352 and DPIS 2-2353 is to isolate the HPCI System in the event of a breakace in the HFCI steam supply pipinc.
Although the switches drif t.cd above the Technical Specificatiens, they did operate, and in the event of a break in the steam piping would have isolated the HPCI System at 151 inches differential pressure. Consequently, we conclude that this slight cwitch drift presented no safety hazard.
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.pn 8304210051 730115 gDRADOCK 05000237 I
522 PDR I
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j M FCTIVE ACTIO'!
P As trentiend above, the manufacturer of Barton !<cdel //20P switches has been ecnaulted concerninr* this drift proble:r, and has made specific roccreendations as to a corrective action. Thic corrective action consists of installinn lockint', devices en the switch caldbratine cerews. The corree-tive action will be applied as eoen as the locking devices are available.
A follow up ctudy will be rerferr.ed to assure t aat the lockint* devices have corrected the drift problem on the Bartcn !hiel h2PP switches.
A follow up letter vill be provided upon completion of this study.
Sincerely, T
W " A-
'd. P. h'orden Drecden Nuclear Power Station h74:W:jw cc:
W. Ilildy h7n' Ltr. File fi 1 5 2 2