ML20084C917

AO 50-219/74/41:on 740719,main Steam Line Low Pressure Switches RE23C & D Found to Trip at Pressures Less than Min of 860 Psig.Caused by Lack of Setpoint Tolerances in Tech Specs.Setpoint Accuracy & Tolerance Under Investigation

ML20084C917
Person / Time
Site:	Oyster Creek
Issue date:	07/26/1974
From:	Finfrock I JERSEY CENTRAL POWER & LIGHT CO.
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
References
AO-50-219-74-41, NUDOCS 8304080345
Download: ML20084C917 (4)

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MAD! SON AVENUE AT PUNCH BOWL ROAD

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Mr. A. Giambusso c S~ y fif z,y,,(%y u v:

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Dear Mr. Gicmbusso:

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Subject:

Oyster Creek Station Docket No. 50-219 annn m i . .c ciirran co unnner sn w_,sy,,arai l The purpose of this letter is to forward to you the attached i

Abnormal Occurrence Report in compliance with paragraph 6.6.2.a of the Technical Specifications.

Enclosed are forty copics of this submittal.

Very truly yours, 1

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! Ivan R. Finfrock, Jr.

Vice President

.i es Enclosures I cc: Mr. J. P. O'Reilly, Director Directorate of Regulatory Operations, Region I l

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Jersey Central Power & Light Company y wl MADISON AVENUE AT PUNCH BOWL ROAD

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I OYSTER CREEK NUCLEAR GENERATING STATION FORKED RIVER, NEW JERSEY 08731 Abnormal Occurrence Report No. 50-219/74/41 en i D

\' /q Report Date July 26, 1974 2

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July 19, 1974 A U3 Identification of Occurrence Violation of the Technical Specifications, paragraph 2.3.7, main steam line low pressure switches RE23C and D were found to trip at pressures less than the mininua required value of 860 psig. This event is considered to be an abnormal occurrence as defined in the Technical Specifications, paragraph 1.15A.

Conditions Prior to Occurrence The plant was at steady state power with major parameters as follows:

Power: Reactor, 1895 E t Electric, 641 We Flow: Recirculation, 57.6 x 106 lb/hr "

Feedwater, 7.08 x 106 lb/hr Reactor Pressure: 1020 psig Stack Gas: 16,000 pCi/sec Description of Occurrence On Friday, July 19,1974, at 1023, while performing a routine surveillance test on the four main steam line low pressure switches, it was discovered that suitches RE23C and D tripped at S55 and 853 psig, respectively. These values are below the mininun required trip point of 860 psig which is derived by adding to the Technical Specification limit of 850 psig, a 10 psig head correction factor.

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Abnormal Occurrence Report No. 50-219/74/41 Page 2 The "as found" and "as Icft" switch settings were:

"As Found" Settings "As Left" Settings RE23A 860 psig 860 psig RE23B 860 psig 860 psig RE23C 855 psig 860 psig RE23D 853 psig 861 psig Apparent Cause of Occurrence

, This event is considered to be reportable because of the lack of set point tolerances in the Technical Specifications.

Analysis of Occurrence As indicated in the bases of the Technical Specifications, "The low pressure isolation of the Main Steam Lines at 850 psig was provided to give protection against fast reactor depressurination and the resultant rapid cooldown of the vessel. Advantage was taken of the scram feature which occurs when the Main i Steam Isolation Valves are closed to provide for reactor shutdown so that high pnwer nne ration ar inw react or utessure due3 not vaui . Lhus viuvidlux gwi%;a..

i for the fuel cladding integrity safety limit."

The adverse consequences of reactor isolation occurring at reactor pressure approximately 7 psig below the specified minimum value of 860 psig is limited to those effects attendant to a greater than normal reacter cooldown rate. The fuel cladding integrity safety limit only comes into effect for power operation

> at reactor pressures less than 600 psig or for power operation greater than 354 MWt with less than 10'a recirculation flow. Therefore, the consequences of a 7 psig lower than normal reactor isolation and scram set point has no threatening effect whatsoever on the fuel cladding integrity.

The effects of a too rapid cooldown due to the lower isolation pressure are inconsequential since there is less than 1*F difference between the saturation temperature for 850 psig and 843 psig. ..

Corrective Action j

Set point accuracy and tolerance in not only these instruments but in others as well are under investigation by Jersey Central Power 6 Light Company, GPU Service Corporation, and General Electric Company persennel as described in Abnormal Occurrence No. 50-219/74/35.

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. Oe u Abnormal Occurrence Report No. 50'-219/74/41 Page 5 Failure Data Manufacturer data pertinent to these switches are as follows:

Meletron Corporation (subsidiary of Barksdale)

Los Angeles, California Pressure Actuated Switch Model 372 Catalog No. 372-6SS49A-293 Range 20-1400 psig Proof Psi 1750 G Previous abnormal occurrence reports involving these switches are:

l 1. Letter to Mr. A. Giambusso from b'r. D. A. Ross, dated l December 24, 1973.

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2. Abnormal Occurrence Report No. 50-219/74/1

3. Abnormal Occurrence Report No. 50-219/74/9

4. Ahnnrnal Occurrence Report No. 50-219/74/10

5. Abnormal Oc.currence Report No. 50-219/74/12 l

6. Abnormal Occurrence Report No. 50-219/74/22

7. Abnormal.0ccurrence Report No. 50-219/74/35

8. Abnormal Occurrence Report No. 50-219/74/37 l

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j TO: James P. O'Reilly ~. # eg &"n --

Directorate of R'egulatory Operations bS'%I8/f 3En: ' -

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l FROM: Jersey Central Pewer S Light Compcny Oyster Creek Nuclear Generating Station Docket #50-219

Forked River, New Jersey 08731 1

SUBJECT:

Abncrmal Occurrence Report No. 50-219/74/41

.i The following is a preliminary report being submitted in compliance with the Technical Specifications, paragraph 6.6.2.

Preliminary Approval:

O M- t 7/19/74

J. T. Carroll J r. Date i- cc

Mr. A. Giambusso vpy}

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Initial Telephone Report Date:

h 77/9 / 74 Date of Occurrence:

O 7/19 / 74 Initial Writ'ren ' Time of t

Report 'Dat e

7/19/74 Occurrence: 1023 I

j OYSTER CREEK NUCLEAR GENERATING STATION 2 FORKED RIVER, NEW JERSEY 08731 i

J Abnormal Occurrence lr Report No. 50-219/74/ 41 i .

I l IDENTIFICATION Violation of the Technical Specifications, paragraph 2.3.7, j OF OCCURRENCE:

j Main Steam Line Low Pressure Switches RE23C and D were found  !

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1 860 psig.

1 1 This event is considered to be an abnormal occurrence as de-

! fined in the Technical Specifications, paragraph 1.15A.

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{ CONDITIONS PRIOR X Steady State Power Routine Shutdown ,

TO OCCURRT.NCE: Hot Stemdhv Onerati on s l Cold shut $ awn Loaa tnanges uuring 1 Refueling Shutdown Routine Power Operation Routine Start Other (Specify) j j Operation I

Power: Reactor,1895 Mit

Elec., 641 MWe Flow: Recirc. , 57.6 X 10 6 lb/hr Feed.,'7.08 X 106 lb/hr l;

Reactor Pressure: 1020 psig Stack Gas: 16,000 pCi/sec 1

I DESCRIPTION OF On Friday, July 19,1974, at 1023, while performing a routine ,

, OCCURRENCE: i surveillance test on the four Main Steam Line Low Pressure '

Switches, it was discovered that switches RE23C and D tripped  ;

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at 855 and 853 psig, respectively. These values are below l I l

] the minimum required trip point of 860 psig which is derived  ;

1 by adding to the Technical Specification limit of 850 psig a 10 psig head correction fac' tor. f/

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Abnormal Occurrence . , ,

FWport No. 50-219/74/41 Page 2 J

'Ihe "as found" and "as left" switch settings were:

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"As Found" Settings "As Left" Settines RE23A 860 psig 860 psig

, RE23B 860 psig E60 psig l RE23C 855 psig 860 psig l RE23D 853 psig 861 psig i

i APPARENT CAUSE X Design Procedure 0F OCCURRENCE: Manufacture Unusual Service Condition Insta11atien/ Inc. Environmental 1 Construction Component Failure j Operator Other (Specify) l j

j The cause of this occurrence is switch repeatability, whidi l .

j is a recognized problem, i

j ANAL,YSIS OF As indicated in the bases of the Technical Specifications, "The low pressure isolation of the Main Steam Lines at 850 l psig was provided to give protection against fast reactor

, depressuri:ation and the resultant rapid cooldown of the 1

1 j vessel. Advantage was taken of the scram feature which occurs

] when the Main Steam Isolation Valves are closed to provide i

j for reactor shutdown so that high power operation at low '

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reactor pressure does not occur, thus providing protection for the fuel cladding integrity safety limit."

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l The adverse consequences of reactor isolation occurring at I

reactor pressure approximately 7 psi.g below the specified

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l minimum value of 860 psig is limited to those effects atten-1 j dant to a greater than normal reactor cooldown rate. The fuel cladding integrity safety limit only comes into effect

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Abnormal Occurrence . .. .

Report No.- 50-219/74/41 Page 3 a

for power operation at reactor pressures less than 600 psig or for power operation greater than 35.4 Mh't with less than 10's recirculation flow. Therefore, the consequences of a 7 psig lower than normal reactor isolation and scram setpoint has no threatening effect whatsoever on the fuel cladding

. integrity.

The effects of a too rapid cooldown due to the lower isola-tion pressure are inconsequential since there is less than 0

1F difference between the saturation temperature for 850 ,

psig and 843 psig.

CORRECTIVE Setpoint accuracy and tolerance in not only these instruccnts As- TIGli:

but in others as well is under investigation by Company and-GPU personnel with General Electric Company FAILUNI DATA: bbnufacturer data pertinent to these switches are as follows:

Meletron Corp. (subsidiary of Barksdale)

Los Angeles, California .

Pressure Actuated Switch Model 372 Catalog #372-6SS49A-293 Range 20-1400 psig Proof Psi. 1750 G Previous Abnormal Occurrence Reports involving these switches; are:

1. Letter to Mr. A. Giambusso from Mr. D. A. Ross, dated December 24, 1973.

2. Abnormal Occurrence Report No. 74-1.

3. Abnormal Occurrence Tieport No. 74-9.

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Abnormal Occurrence ** -

l Report, No. 30-219/74/41 Page 4  ;

. 4. Abnormal Occurrence Report No. 74-10.

] 5. Abnormal Occurrence Report No. 74-12.

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6 Abnormal Occurrence Report No. 74-22. t t

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7. Abnormal Occurrence Report No. 74-35 1 8. Abnormal Occurrence Report No. 74'-37.

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Abnormal Occurrence i..- -

Report,Nos 30-219/74/41 Page 4

. 4. Abnormal Occurrence Report No. 74-10.

l S. Abnormal Occurrence Report No. 74-12,

6. Abnormal Occurrence Report No. 74-22.

7. Abnormal Occurrence Report No. 74-35.

8. Abnormal Occurrence Report No. 74-37.

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o PICpared by: u f/ '#

k] !7 Date: 7/19/74