ML19210A231

Abnormal Occurrence 50-289/75-21:on 750625,coolant Temp Trip Bistable Channel C Failed to Trip During Test of Reactor Protection Sys.Caused by Defective Printed Circuit Board Solder Joint in Signal Converter

ML19210A231
Person / Time
Site:	Three Mile Island
Issue date:	07/03/1975
From:	Arnold R METROPOLITAN EDISON CO.
To:
Shared Package
ML19210A232	List: ML19210A231 ML19210A235
References
GQL-1235, NUDOCS 7910240945
Download: ML19210A231 (4)

Text

,

i:RC E TRIBUTION FOR PART EO DOCKE! 1ATERIAL

.' (TEMPOR ARY FOR:.1)

CONTROL NO: 9I9O

' " FILE: INCIEE -T EEPOPT FII:-

FROM: Metropolitan Edison co DATE OF DOC DATE REC'D LTR TWX RPT OTHER Reading, Pa R C Arnold 7-3-75 7-7-75 XXX CC OTHER SENT AEC PDR YY TO ORIG DL one signed y :.NT LOCAL PDR XX UNCLASS PROPINFO INPUT NO CYS REC'D 00CKET NO:

CLASS XXXXX 1 50-289 DESCRIPTION:

ENCLOSURES:

Ltr reporting abnormal occurrence #75-21 v , ._

a ~vu IGM, OVE'

~

on 6-25-75 concerning failure of a high re-actor coolant temperature trip bistable to trip.........

ACKXOTLEDGED' PLANT NAME: Three Mile Island #1 .

FOR ACTION /INFORMATION 7-8-75 ehf SCHWE NCER (L) ZIEMANN (L) REG AN (E)

DUTLER (L) W/ Copics W/ Copies W/ Copies W/ Copies CLARK (L) STOLZ (L) DICKER (E) LE AR (L)

W/ Cocies W/ Cocies / W/3 Copies W/ Cooics PARR (L) VASSALLO (L) KNIGHTON (E) SPELS W/ Copies W/ Copies W/ Copies W/ Copies KNIEL (L) PURPLE (L) YOUNGBLOOD (E)

W/ Copics V// Copies W/ Copics W/ Copics INTERN AL DISTRIBUTION L!C ASST A/T IN D_

<%O MM TECH REVIEW pSCHROEDER CENTON yGRIMES R. DICGS (L) B R AITM AN f NRC POR G AMMILL H. GE ARIN (L) SALTZi.1AN OGC. ROOT.1 P 50GA /MACCARY MELTZ GOSSICK/ST AF F KNIGHT KASTNER E. G JULBOURNE (L)

CASE PAWLICKl BALLARD P. K3EUTZER (E) f SPANG LE R J. LEE (L) PLANS GIAMBUSSO SHAO MCDONALD BOYD **s STE L LO M. fG A!G RET (L)

ENVIRO- S. REED (E) CHAPMAN MOORE (L) **fHOUSTON DUBE (L:r)

DEYOUNG (L) **f NOVAK MULLER M. SERVICE (L)

DICKER S. SHEPPARD (L) E. COUPE SKOVHOLT (L) P.OSS PETERSON GOLLER (L) (Ltr) p lPPO LITO KNIGHTON M. SLATER (E)

YOUNGBLOOD H. SMITH (L) HARTFIELD (2)

P. CO L LINS /TEDESCO KLECKER DENISE J. COLLINS REGAN ,,S. TEETS (L)

PROJECT LDR G. WILLI AMS (E) EISENHUT REG OPR LAIN AS *WIGGINTON

/Fil E & REGION (2) BENAROYA V. WILSON (L)

.e.14IPC/PZ VOLLMER HAR LESS R. INGRAM (L) F. WILLI /?is

($) , prug, STEELE

_ EXTERN AL DISTRIBUTION P> d el - LOCAL PDRj_4 H u ho**5 e k 1 - PDR SAN /LA/NY pl - TIC (ABERNATHY) (1)(2)(10) - N ATION AL LABS 1 - BROOKH AVEN ' AT LAB 1 - W. PENNINGTON, Rm E-201' GT f l - NSIC (BUCHAN AN) 1 - G. ULRIKSON. CR'.L 1 - ASLB 1 - CONSU LTA*JTS 1 - AGMED (RUTH GLIS. ' ':,,

1_,- Newton Anderson NEWM ARK /B LUM E/AG B AB! AN Rm B-127 GT A ACRS SE:7 TO LIC 1.SST -fesf 4 -

1 - J. D. RUNKLE'S, Rm E :01

• • SE:iD 0::LY TE.'i D/J RI?CRTS

\O <]) GT 1910240 9 9er 3

U.,4c + . &n J

,WQ..

- m ,-,m METROPOLITAN EDISON COMPANY .

PCtT CFF!CE BOX 542 READ:NG, PENNSYLVANIA 19603 TELEPHONE 215 - 929-0601 July 3,1975 GQL 1235 -

~.

, - .,. . t i n-, .-.

, ;.; n.

Director Division of Reactor Licensing

' D ') ,

3- ,

~

U.S . Nuclear Regulatory Commission s .

Washington, D.C. 20555

'q}N j -

N >

Dear Sir:

Docket No. 50-289 Operating License No. DPR-50 In accordance with the Technical Specifications of our Three Mile Island Nuclear S tation Unit 1 (TMI-1) , we are reporting the followi .,1 occu rren ce. p< \ "/

(1) Repr*t Number: A0 50-289/75-21 cy 3 r-(2a) Report Date: July 3, 1975 i,

7.g., C-! ,

(2b) Occurrence Date: June 25, 1975 \ O u.s.gpyj,5jj^' ' [/

h'j ag "

s (3) Facility : Three Mile Island Nuclear Station Unit l

/ ' an * \ \@

(4) Identification of Occurrence:

Title:

Failure of a High Reactor Coolant Temperature Trip Bistable to trip.

Type: An abnormal occurrence as defined by the Technical Specifications , paragraph 1.8d, in that failure of a High Reactor Coolant Temperature Trip Bistable to trip constituted failure of one or more components of an engineered safety feature or plant grotection system that threatened to cause the feature or system to be incapable of performing its intended function.

(5) Conditions Prior to Occurrence:

Power: Core: 99%

Elect.: 850 MWe Gross }h h 274 RC Flow: 140.68 x 10 lbs/hr 7180

RC Pressure: 2155 psig RC Temp . : 379 F PRZR Level: 240 inches PRZR Temp . : 655 F (6) Description of Occurrence:

While conducting routine surveillance of the Reactor Protection System (RPS) the Reactor Coolant Temperature Trip Bistable for channel "C" failed to trip. The remaining three RPS channels were immediately checked and found to be operable. Further, the defective trip circuit of channel "C" was then replaced and verified to be operable.

(7) Designation of Apparent Cause of Occurrence:

The apparent cause of this occurrence has been determined to be material in that the failure of the High Reactor Coolant Temperature Trip Bistable to trip was traced to a defective printed circuit board solder joint in the signal converter. This defective solder joint prevented the trip signal from reaching the trip bistable.

(8) Analysis of Occurrence:

It has been determined that this occurrence did not represent a threat to the health and safety of the public, in that

a. the high temperature trip feature of the remaining three RPS channels was immediately verified to be within Technical Specification limits, and

b. only two high temperatura trip channels are required to function for safety protection, and three were functioning properly, and

c. the failed channel was immediately replaced, tested and returned to service.

(9) Corrective Actions:

In addition to the immediate corrective actions listed above, the defective channel "C" signal converter was repaired and tested and the results were satisfactory.

The Plant Operations Review Committee and Station Superintendent have reviewed and approved the above listed correc tive actions.

e

-3_

(10) Failure Data:

Bailey System 880 Reactor Protection System Signal Converter (E92-346)

Similar Occurrences : none Sincerely, i} n Vice-President RCA:CWS:pa ec: Mr. J. P. O'Reilly, Director Office of Inspection and Enforcement, Region 1 U.S . Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 File 20.1.1 7.7.3.5.1 1476 276