ML20086K914

AO 74-28:on 740525,switch DPIS-2-2-118D Failed to Trip Consistently.Caused by Improper as-built Positioning of Mercury Bulb Type Reed Switch.Mercury Bulb Repositioned to Provide Positive & Consistent Operation

ML20086K914
Person / Time
Site:	Peach Bottom
Issue date:	06/04/1974
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20086K917	List: ML20086K914 ML20086K924
References
AO-74-28, NUDOCS 8402070072
Download: ML20086K914 (2)

Text

l

'~ ' ,

4,-

a '

e PHILADELPHIA ELECTRIC COMPANY 2301 M ARKET STREET PHIL.S.DELPHI A. PA.19101 (215)841-400o June 4,1974 fir. A. Giambusso Deputy Director of Reactor Projects United States Atomic Energy Commission Directorate of Licensing 50 *<> ea

~

Washingt on, DC 20545

Subject:

Abnormal Occurrence The following occurrence was reported to tir. A. D. Toth, A.E.C.

Region I Regulatory Operation: Office on May 26, 1974. Written notifi-cation was made to tir. James P. O'Reilly, Region I Regualtory Operations Of fice on May 28, 1974. In accordcnce with Section 6.7.2.A of the Tech-nical Specifications, Appendix A of DPR-44 for Unit 2 Peach Bot tom Atomic Power Station, th: following report is being submitted to the Directorate of Liccasi.u a:., on Aboorma! accur er nca

Reference:

License flamber DPR-44, Amendment flumber 1 Tecnnical Specification Table 4.2.A Report flo.: 50-277-74-28 Report Date: June 4, 1974 Occurrence Date: May 25,1974 Facility: Peach Bottom Atcmic Power Station R. D. 1, Delta, Pennsylvania 17314 f

s Identification of Occurrence: -'

! t , < ! ..

Failure of dPIS-2-2-II80 to trip consistently.

, ," .( ; , -' ,,

, '~ D_ ' : , , ' _ /\

, 'u .-

Conditions Prior to Occurrence:  ; 4 +.

/7l

/#,.

t -' ,,Q.Y Plant operating at close to rated power, ,

y. q ., J N.M., , - . 3. <i-\<.'

Description of Occurrence:

During a functional instrument surveillance test, dPIS-2-2-Il8D, a PCIS Group I input on liain Steam Line High F low, failed to trip con- f sistently. This switch monitors steam flow'in the "C" Mein Steam Line. #

g.,Lqf' egg 2g[3g@fo$o8 S

/

'}

mn star azotow -

Mr. A. Giambusso s gs June 4, 1974 (_) (,) Page 2 Jh. o '

• Desionation of Acoerent Cause of Occurrence:

Improper "as built" positioning of the mercury bulb type reed switch such that the magnet would not f ully pick up the reed consi stently.

When the switch did function, however, it did function at the proper setpoint.

Analysis of Occurrence:

There are no safety implications associated with this occurrence si nce its companien switch in a one-of-two-twice logic on the same steam line had just been tested and found fully operable.

Corrective Action:

The mercury bulb was repositioned to provide positive and consistent operation. The device was recalibrated and tested per the calibration check type of surveillance test which includes a functional test. On May 27, 1974, the other 15 similar switches were inspected for a similar problem and functicnally tested. No f ailures were noted and no adjustments were necessary.

Failure Data:

A functional f ailure of a similar switch was reported as an Abnormal Occurrence on September 6,1973 Very truly yours, j ;,

/ s r M. J: Cooney '

As s ' t. Gen't Superintendent Generation Division cc: Mr. J. P. O'Reilly Director, Region i United States Atomic Energy Conmission 631 Park Avenue King of Prussia, PA 19406

_ . . . . _ _ .