ML20086K544

AO 75-4:on 750117,core Spray B stay-full Accumulator Level Switch LS-4224 Failed to Operate on Low Accumulator Level. Caused by Binding of Float.Float Freed.Float Switch Removed from Accumulator & Checked for Freedom of Motion by Hand

ML20086K544
Person / Time
Site:	Peach Bottom
Issue date:	01/27/1975
From:	Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Giambusso A Office of Nuclear Reactor Regulation
Shared Package
ML20086K549	List: ML20086K544 ML20086K550
References
AO-75-4, NUDOCS 8401270237
Download: ML20086K544 (2)

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PHILADELPHIA ELECTRIC COMPANY 2301 M ARKET STREET PHILADELPHI A. PA.19101 g' -

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b January 27, 1975 . f' . .

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Mr. A. Giambusso '

s Director, Division of Reactor Licensing Of fice of Nuclear Reactor RegJ1ations \ * => d.i U3.t Cq."h .;. '

U. S. Nuclear Regulatory Commission -

Washington, DC 20555

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Subject:

Abnormal Occurrence The following occurrence was reported to Mr. E. J. Brunner, N.R.C. Region 1 Regulatory Operations Office on January 18, 1975 Written notification was made to Mr. James P. O'Reilly, Region 1 Regulatory Operations Office on January 20, 1975 In accordance with i

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 bein.g submitted to the Directorate of Licensing as an Abnormal Occurrence.

Reference:

License Number DDR-44

• Technical Specification

Reference:

5.4.G . 2 Report No.: 50-277-75-4 i

Report Date: January 27, 1975 l

Occurrence Date: January 17, 1975 l Facility: Peach Bottom Atomic Power Station R.D. 1, Delta, Pennsylvania 17314 I

Identification of Occurrence:

Failure of the "B" Core Spray Stay-Full Accumulator level

! switch LS-4224 to operate on low accumulator level.

Conditions Prior to Occurrence:

Unit 2 shutdown for scheduled maintenance.

. Description of Occurrence:

s Durino routine surveillance testing of the "B" Core Spray

. Stay-F ul l' Accumalat or level switch (LS-4224), draining the accumulator

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I. failed to bring up the control room annunciator or operate the stay-full vent solenoid SV-4224.

44 -o 8401270237 750127 .L .L .!. O PDR ADOCK 05000277 S PDR l

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'Mr. A. Giambusso .

January.27,J1975 Page 2 Designation of Apparent Cause of Occurrence:

Float was apparently binding.

Analysis of. Occurrence:

The fact that this switch would not operate has very little safety implication because the system has been pressurized continuously by the condensate _ transfer system. During the surveillance testing it was found that the accumulator was full, indicating that the piping up to and including the accumulator had remained full during previous operation.

s Corrective Action:

The float was freed. Several functional tests proved that the switch was performing satisfactorily. Later, the float switch was re-moved from the accumulator and checked for freedom of motion by hand.

This revealed slight intermittent binding. The float switch was then dismantled.

' The connecting rod was found to have a double bend which was binding against the inside of the isolation tube. The connecting rod was straightened, the switch hand checked for freedon of motion, and the assembly reinstalled on the accomulater. The m:2 teh nam ..uuusa-tully retested in accordance with the approved surveillance test.

Fai lure (Dat a:

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'None.

Very truly yours,

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.h 4 H. . Cooney A s ' t Gen' t Super intendent Generation Division cce Mr. J. P. O'Reilly Director, Region i U. S. Nuclear Regulatory Commissicn 631 Park Avenue King of Prussia, PA 19406

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