ML20086J062

Telecopy AO 75-7:on 750123,mode Switch Failed to Consistently Initiate Full Scram When Moved to Shutdown Position.Caused by Intermittent Switch Contact Function.Mode Switch Replaced

ML20086J062
Person / Time
Site:	Peach Bottom
Issue date:	01/24/1975
From:	Ullrich W PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20086J056	List: ML20086J053 ML20086J059 ML20086J062
References
AO-75-7, NUDOCS 8401230083
Download: ML20086J062 (1)

Text

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i LA PHILADELPHIA ELECTRI 1 ds -d's h' PGech Bottom Atomic Pow MPANY Station ww . s./odt s bu .[.

• Delta, Pennsylvania

( .

17314 January 24, 1975 Mr. James P. O'Reilly, Director United States Atomic Energy Commission Directorate of Regulatory Operations 631 Park Avenue King of Prussia, Pennsylvania 19406 Subj ec_t:

Abnormal Occurrence 24-Hour Notification Confirming J. F. Franz' Office Regulatory Operations phoneon conversation January 24,with Mr. Tom Shedlovsky, A.E.C. Region i 1975.

Reference:

License Number DPR-56 O

Technical Specification

Reference:

%, \ f / e.3 Table 3.1.1 'D Report No.:

Report Date:

50-278-75-7 <

January 24, 1975

g Occurren*ce Date: JanuaYy 23,* 1775 ~ '- ' - - * ~ " " ~

_ s/g 3 Facility: 9-  %,rg)  ;,* jy,h '2 Peach Bottom Atomic Power Station '

c' R.D. 1 Delta, Pennsylvania 17314 .D f,,.h /

Identification of occurrence: p Failure of the tude switch to consistently initiate a full s'4c the shutdown position.

@ moved to 4 Conditions Prior to Occurrence:

Unfe 3 chutd: :.

Description of Occurrence:

)'

. After insertion of all rods and placement of the mode switch in SHITTDOW, the mode control switch rod. was placed in the P.EFUEL position to enable the movement of a single

The mode switch failed to allow the motion of a control rod and the svitch was then cycled to the SHUTDOW posf. tion and back to the REFUEL i

position to clear the report.

{ full scram when moved to the SHUTDOWThis time the mode switch failed to initiate a position.

Designation of Apparent Cause of Occurrence:

Intermittent switch contact function.

Analysis of Occurrence:

Because the reactor was shutdown with all control rods inserted, and because the Manual Scram System was operable, the failure of the full scram . capability of the rode. switch in the SHUTDOW position hss ' minimal safety implications. . .

Corrective Action:

The mode svitch was cycled many tines between SHUIDOW and RIFUEL, and it intermittently failed to initiate full scrams. Because of this, the mode switch is presently being replaced.

Failure Data:

None.

8401230003 750207 PDR ADOCK 05000278 '

Very truly yours, S PDR

/gg -  % 1003 W. T. Ullrich, Superintendent -

Peach Bottom Atomic Power Station

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