ML20085K151

Ao:On 731112,steam Flow Switches 3-2352 & 3-2353 for HPCI Sys Found Out of Calibr.Caused by Setpoint Drift.Switches Reset

ML20085K151
Person / Time
Site:	Dresden
Issue date:	11/20/1973
From:	Worden W COMMONWEALTH EDISON CO.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085K154	List: ML20085K151 ML20085K155
References
865-73, NUDOCS 8310200213
Download: ML20085K151 (2)

Text

- -

j

. . .; ( j d

~m Cm arith Edis:n One First .ational Plua Chicago Illinois Address Reply to: Post Office Box 767 Chicago. Ilknois 60690 WFW Ltr.#865-73 Dresden Nuclear Power Station R. R. #1 Morris, Illinois 60450 November 20, 1973  %

\."b1D W rf Nj 50-249 N'-

Mr. J. F. O' Leary, Director 2' .ii i

Directorate of Licensing U. S. Atomic Energy Co: mission D 21 2

, [(

4 'i < pr. i Washington, D. C. 20545 c, pVp 7

SUBJECT:

LICENSE DPR-25, DRESDEN NUCLEAR POWER STATION, UNIT #3, q, 3j REPORT OF ABNORMAL OCCURRENCE PER SECTION 6.6.B.1 OF THE #

TECHNICAL SPECIFICATIONS.

HPLI SYSTEM HICH STEAM FLOW ISOLATION SWITCHES OUT OF CALIBRATION.

References:

1) Notification of Region III of AEC Regulatory Operations Telephone: H. Dance 1430 hours0.0166 days <br />0.397 hours <br />0.00236 weeks <br />5.44115e-4 months <br /> on November 13, 1973.

Telegram: J. Keppler 1500 hours0.0174 days <br />0.417 hours <br />0.00248 weeks <br />5.7075e-4 months <br /> on November 13, 1973 4

2) Dwgs: P & ID M-51.

Dear Mr. O' Leary:

The folicwing is to report a condition relating to the operation of the unit in which at 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br /> on November 12, 1973, the steam flow switches for the High Pressure Coolant Injection System were found to be out of calibration.

This is a violation of Table 3.2.1 of the Technical Specifications

] which require a setting of ,f.,150" H 2O dp increasing.

FROBLEM The switches in question are dpis 3-2352 and 3-2353. They are

Barton model 288 differential sensors and were found with setpoints of 152" water and 160" water respectively.

I INVESTIGATION The function of these switches is to isolate the High Pressure Coolant Injection System (HPCI) in the event of a break in the steam supply-line. Barton model 288 switches have~a history of setpoint drift in both the increasing and decreasing direction. The switches were last calibrated on October 9,.1973. At that time, switch DPIS 3-2352 was set'at 144.5" i

water and DPIS 3-2353 was set at 148.0" water. These switches therefore drif ted 7.5" and 12" respectively in a period of e

32 days. . ~.>

8310200213 731120 PDR ADOCK 05000249

\ M -O' S .-

PDR f) ,(?-@ )M blj

> ~

CUPV BENT REGION

l

..g, Mr.J.F.O'LQery O Nov:mbar 20, 1973

-d l

~

)

CORRECTIVE ACTION ~

These switches were immediately reset to comply with the Technical Specification. The problem with Barton switches is presently under investi-gation by the Dresden Instrument Department, the local sales representative of ITT Barton Company, and ITT Barton Factory representatives.

The local sales representatives have made several field trips to l Dresden Station and have analyzed several switches which have a drif t history. They have found several significant problems on several switches which include mis-applications and loose or distorted components. The representative will return to complete an analysis on all problem switches and a plan to implement their recommendations will be formulated.

EVALUATION l The switches did not trip at the desired setpoint but did trip, i

and would have functioned at a differential pressure of 152", which is only 2" above the Technical Specification limit. It is therefore concluded that the safety of the station personnel or the general public was not jeopardized as a result of this instrument drif t.

The corrective actions in progress are directed toward reducing setpoint drift problems. In the meantime, redundancy in similar systems' instru=entation, shortened intervals between surveillance tests, and con-servative setpoint values have reduced the ef fect of these drif ting set-points to where continued operation of the units is safe.

S incerely, W .d w W. P. Worden Superintendent WPW:do I

l

. .. . _ - _ _ - - _ - _ _ _ . - . . - - _ .-