ML20086L113

Telecopy AO 74-1:on 740105,setpoint Shift Found on Switches LIS-2-2-3-101C & PS-2-5-11A & D.Setpoint Shift on LIS-2-2-3-101C Caused by Binding of Cam Follower.Cause of Shift on Switches PS-2-5-11A & D Still Under Investigation

ML20086L113
Person / Time
Site:	Peach Bottom
Issue date:	01/07/1974
From:	Ullrich W PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
AO-74-1, NUDOCS 8402070398
Download: ML20086L113 (1)

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OJanuary 7, 1974 .

Mr. Jame:: P. O'Reilly, Director United States Atomic Energy Com:iscion d ,,/ [

• 3 3 7 / N 8 b Directorate of Regulntory Operations 631 Park Avenue hedh, r L

King of Praccia, Pennsylvtmia 19406 l

Subject:

. Abnor:n1 Occurrence 2LHour Notificatien p3 [

Confirming cy telephone cenvercaticn with Mr. R. T. Caricon, A.E.C. Region I 7

Reguintory Office on January 6,1974.

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Reference:

. License Hucher DPR 44, Amendment Number 1, l g-

%~2 Technical Specification Table 31.1 h 0, -

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-3 i Report No. 50-277-74-1

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Eepart Date: 1-7-74 .

Occurrence Dato: 1-5-74

, Facility: Peach Botton Atomic Power Station - Unit 2  ;

R.D. 1, Delta, Pennsylvania 17314 -

Identification of Occurrence .

A. Setpoint chift on LIC-2-2-3-101C which provideo a Reactor High Vater [

Level turbine trip input to the RCIC and the Main Turbine trip logics.

B. Setpoint shift on PS-2-3-11A 6.D uhich provides an R.P.S. trip input on Condeneer Low Vacuur. r Conditionc Prior to Occurrence * ~

Reactor critical and vented at 160 F coolant'tecperature.  ;

Description of.0ccurrence:  :

. A. LIS-2 2-F1010, Sv #3: Switch tripped at appro..icately h8.5" Reactor  :

Level insttad of S. 45" Reactor Level as cpecified.. --

B. PS-2-5-11 A C: D: Evitch tripped at 22.2" Hg and 22.4" Hg recpectively instead of > 23" Hg ac specified.

Designation of Apparent Cauce of Occurrenec:

i A. LIS-2-2-3-1010, Sv #3: 'Can follower for Sv #3 was found to.be binding i sufficiently with the etc to prevent proper following of~ the can contour. .

B. P3-2-5-11A L D: Investigation in progress.-

Analyaic of Occurrence:

Sotpoint shift of the subject cvitches would not have defeated the logic to produc,o the required actions. Operable evitches would have cauced  ;

trips at the proper setpoints.' : Setpoint shifts were cinor and have no safety icplicationc.  ;

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Corrective Action:

i A. LIS-2-2-3-1010, Ed #3: Calibration checked, setpoint reset and checked .

I and functionnlly tected following repincoment of bent en follover.  ;

B. PS-2-3-11A b D: Sotpoint react to 23 7" Hg and-23 5" Hg respectively, ar.d checked repeatedly with no. evidence of further uhift.

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V. T. Ullrich, Superintendent o d  :

Peach Botton Atonio Power Station >  ;

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10 (Name a d unst) HelflAL5 REMARA5 R0 Chief, FS&EE PilILADELPilIA ELECTRIC COMPANY RO:llQ (5)

RO Files cATE PEACl! BOITOM 2 Central Mail 6 Files Regulatory Standards (3) A0 74-1/2/3 TO (Name an un.ts INati AL.5 REMAAns Directorate of The above abnormal occurrence is forwarded Licensing (13)

OGC DATE for information. Distribution will be made --

Regional Directors (II , III , IV) by this office to the PDR, Local PDR, NSIC, 10.(Name and unit) INITIALS RLMARKS DTIE, and' State Representatives after review oArE by the licensee for proprietary information.

F F40M (N ame and unit) REMARK 5 E. J. Brunner Region I /

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January 15, 1974 Mr. A. Giambusso Deputy Director of Reactor Projects United States Atomic Energy Commission Directorate of Licensing Washington, D. C. 20545

Dear Mr. Giambusso:

Subiect: Abnormal Occurrence The following occurrence was reported to Mr. R. T. Carlson, A.E.C. Region I Regulatory Operations Of fice.

In accordance with Section 6.7.2.A of the Technical Specifications, Appendix A of DPR-44 for Unit 2 Peach Bottom Atomic Power Station, the following report is being submitted to the Directorate of Licensing as an Abnormal Occurrence.

Reference:

License Number DPR-44, Amendment Number 1 Technical Specifications Table 3.1.1 Report No: 50-277-74-1 Report Date: 1-15-74 Occurrence Date: 1-5-74 Faci li ty: Peach Bottom Atomic Power Station - Unit 2 R.D.1, Del ta, Pennsylvania 17314 Identi fication of Occurrence:

T. Setpcint shi f t on LIS-2-2-3-10lc which provides a Reactor High Water Level turbine trip input to the RCIC and the Main Turbine trip logics.

B. Setpoint shi f t on PS-2-5-11A & D which provides an R.P.S. trip input on Condenser Low Vacuum.

Conditions Prior to Occurrence:

Reactor critical and vented at 160 F coolant .

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Description of Occurrence: '

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During instrument surveillance testing, LIS-2-2-3-101C, /?

O 4 switch #3 tripped at approxima'tely 48.5" Reactor Level b

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instead of (45" Reactor Level as specified gggENT

.Technt.:al , Speci fica ti ons.

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, Mr. A. Giambusso O O Jan. 15, 1974 Page 2

8. During instrument surveillance testing, PS-2-5-11A & D switches tripped at 22.2" Hg and 22.4" Hg respectively instead ofy23" Hg as specified in the Technical Speci f i cat i_ons.

Designation of Apparent cause of Occurrence:

A. LIS-2-2-3-101C, Switch #3: The cam follower (on the switch actuator) for switch #3 was found to be binding sufficiently with the cam to prevent proper following of the cam contour.

B. PS-2-5-ilA & 0: The investigation to determine the cause of setpoint drift is still in progress.

Analysis of Occurrence:

The setpoint shif ts of the subject switches would not have defeated the logic to produce the required safety actions. The other operable switches would have caused trips at the proper setpoints. These setpoint shif ts were minor and have no safety implications.

-Corrective Action:

A. LIS 2-2-3-101C, Switch #3: Switch #3 was replaced. The instrument was then calibration checked, the setpoint reset and checked, the switch functionally tested, and the instrument restored to service. A representative of the manufacturer's design engineering section was brought on site to aid in this investigation. No major cause for the setpoint shifts were identified.

Some minor suggestions as to the manner of finely adjusting the switches and the switch actuators for position and roller pressure were made. A minor change in the calibration check procedure to provide better repeatability of setpoint reading was also suggested.

Investigation by Philadelphia Electric Company Engi-neering & Research Department is continuing.

B. PS-2-5-IIA & D: The setpoints were reset to 23 7" Hg and 23 5" Hg respectively, and checked repeatedly with no evidence of further setpoint shift. The manufac-turer has been contacted to provide technical assistance in this continuing investigation.

Failure Data:

A. LIS-2-2-3-101C, Switch #3: These differential pressure switches have required frequent re-calibrations to correct setpoint shi'fts. During the past 20. weeks, -

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,, .Mr. A. Giambussa

,. Jan. 15, 1974 Page 3 surveillance tests performed monthly on these devices have identified shif ts in setpoint on 12 occasions.

Shifts to values in excess of Technical Specification limits occurred 4 times including this occurrence.

B. PS-2-5-ilA & D: There have been no previous calibra-tion or functional problems associated with these particular devices. These switches have been surveil-lance tested monthly for 5 months and have required no re-calibrations until the test performed on January 5, 1974.

Very truly yours, l { '%44p M. . Cooney . '

Ass't Gen'I Supt.

Generation Division cc: Mr. J. P. O'Rei1ly Director, Region 1 i United States Atomic Energy Conunission 631 Park Avenue King of Prussia, PA '19406 I

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