ML20084E040

Preliminary AO 50-219/74/22:on 740315,low Pressure Main Steam Line Pressure Switch RE23D Found to Trip at Pressure Less than Min of 860 Psig.Caused by Switch Repeatability. Recommendations to Eliminate Setpoint Problem Received

ML20084E040
Person / Time
Site:	Oyster Creek
Issue date:	03/18/1974
From:	Carroll J JERSEY CENTRAL POWER & LIGHT CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
AO-50-219-74-22, NUDOCS 8304130335
Download: ML20084E040 (5)

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n; From: Jersey Central Power 4 Light Company Oyster Creek Nuclear Generating Station Docket #50-219 Forked P1ver, New Jersey 08731

Subject:

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

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

Preliminary Approval:

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1[nN?aone L6so otr Rsqort Date: 3/15/74 Occurrence: <3/15/74 Initial Written g Time of h

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3/18/ 74 Occurrence: 1550 O.4 ports Date:

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5 OYSTER CREEK NUCLEAR CENEluTING STATI0'4 ,

' FORKED RIVER, NE;. JERSEY 08731 Abnormal Occurrence Report No. 50-219/74/22 -

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, IDENTIFICATION Violation of the Technical Specifications, paragraph 2.3.7 ,

t.0F OCCURRTNCE:

N Low Pressure Main Steam Line Pressure Switch, RE23D, was

[ found to trip at a pressure less than the minimum required value of 860 psig.

This event is considered to be an abnormal occurrence as de-fined in the Tecimic.a1 Specifications, paragraph 1.15A .

CONDITIONS PRIOR .

TO OCCURRENCE: X Steady State Power Routine Shutdown Hot Standby Ope ration

_ Cold Shutdown Load Changes During

, Refueling Shutdown Routine Power Operation Routino Startup Other (Specify)

Operation Power: Reactor, 1902 Elt Elec. , 661 Die Flow: Recire,, 15.3 x 10" gpm Feed. , 7.10 x 10' lb/hr Reactor Pressure: 1020 psig .

Stack Gas: 40,600 PCi/sec g t

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, ,; g DESCRIPTION On Friday,It! arch 15, 1974, at 1550, while performing a routine OF OCCURRENCE:

surveillance test on the four ! lain Steam Line Low Pressure Switches, it was discovered that RE23D tripped at 850 psig.

This value is below the minimum required trip point of 860 psig which is derived by adding to the Tecimical Specification limit of S50 psig a 10 psig head correction factor.

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Report No. 50-219/74/22 , Page 2 ,

The "as found" and "as Icft" switch settings were:

"As Found" Settines "As Left" Settings RE23A 865 psig 861 psig RE23B 864 psig 864 psig RE23C S65 psig 865 psig RE23D 850 psig 860 psig Pressure switch RE23D was immediately recalibrated and rechecked to actuate at 860 psig.

APPARE.'.T CAUSE X Design. Procedure OF OCCURRENCE: Manufac,ture Unusual Service Condition Installation / Inc. Environmental Construction Component Failure Operator Other (Specify)

Switch repeatability is a recognized problem and work is in progress to formulate a final solution.

ANALYSIS OF As indicated in the bases of the Technical Specifications, "The OCCURRENCE :

Icw pressure isolation of the Main Steam Lines at S50 psig was provided to give protection against fast reactor depressuriza-

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. , tion, and the resultant rapid cocidown o" the vessel. Advantage . , , .

was taken of the scran feature which occurs when the Main Steam

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Isolation Valves are closed to provide for reactor shutdown so that high power operation at low reactor pressure does not occur, thus providing protection for the fuel cladding integrity safety limit."

The adverse consequences of reae. tor i, solation occurring at reactor pressure approximately 10 psig below the specified mini-mum value of 860 psig is limited to.those effects attendant to 9

' Abnormal Occurrence o o Report No. 50-219/74/22 -

Page 3 a greater than normal reactor cooldown rate. The fuel cladding'.

integrity safety linit only comes into effect for power opera-tion at reactor pressures less than 600 psig or for power opera-I tion greater than 354 Mit with less than 10% recirculation. flow.

l Therefore, the consequences of a 10 psig lower than normal l

I reactor isclation and scram setpoint 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 2 F dif-f l

ference between the saturation temperature for 860 psig and -

850 psig.

CORRECTIVE Continuing corrective actions being taken at this tire are as ACTION:

stated in Abnormal Occurrence Report Nos. 74-9, 74-10, and 74-12, and as restated herein:

1. Investigation is being conducted into the basis for the s,, f - , . , . c. . . - . .. ..y . 6... steam line low pressure setting of 850 psig. Development .gz

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of e Technical Specification change to lower the setpoint

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2. - f will follow if results of transient analyses indicate this possibility. (See Abnormal Occurrence Report No. 73-30.)

2. Recommendations to possibly reduce or eliminate the sensor setpoint change problem have been received. It was reported that General Electric tests on a pulsating line to simulate plantconditionsshowthatp're-cfeledBarksdaleswitchesshow improvement but that the switches still do not meet 1% re-peatability. General Electric, therefore, recommended an

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O y/ l Abnormal Occurrence l Report No. 50-219/74/22 -

Page 4 Ashcroft switch as it is more accurate. The Ashcroft catalog number is 61 S 6080 BN20-06L-1028.

As a result, one switch of each type (pre-cycled Barksdale and Ashcroft) has been purchased for test and evaluation at

• Oyster Creek. An Ashcroft switch is currently on hand and

. undergoing evaluation.

FAILURE DATA: Manufactureridata pert'inent 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.

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3. Abnormal Occurrence Report No. 74-9. ,

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4. Abnormal Occurrence Report No. 74-10.

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

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( .b .. Date: 3/18/74

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4. . O o OYSTER CREEK NUCLEAR GENERATING STATION FORKED RIVER, NEW JERSEY 08731 1

Abnomal Occurrence Report No. 50-219/74/22 i

, Report Date j March 22,1974 I

l j Occurrence Date March 15,1974 j

i Identification of Occurrence Violation of the Technical Specifications, paragraph 2.3.7, low pressure main steam line pressure switch RE23D was found to trip at a pressure less than the minimum 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 ne plant was operating at steady-state power.

He major plant parameters at the time of the event were as follows:

i l Power: Reactor,1902 FMt

- Electric, 661 FMe Flow: 4 Recirculation, 15.3 x 10 gpm Feedwater, 7.10 x 106 lb/hr Reactor Pressure: 1020 psig

Stack Gas

40,600 pCi/sec Description of Occurrence On' Friday, March 15, 1974, at 1550, while performing a routine surveillance test on the four main steam line low pressure switches, it was discovered that RE23D tripped at 850 psig. This value is below the minimum 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.  !

The "as found" and "as left" switch settings _were:

j "As Found" Settings "As Left" Settings i

RE23A 865 psig 861 psig -

RE23B 864 psig 864 psig RE23C 865 psig 865 psig RE23D 850,psig 860 psig ygf f

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Abnormal Occurrence No. 50-219/74/22 Page 2 j

S Pressure switch RE23D was immediately recalibrated and rechecked to actuate at 860 psig.

Apparent Cause of Occurrence 1

{ Design is considered to be a major factor contributing to this event. Switch

repeatability is a recognized problem and work is in progress to formulate a 4

final solution.

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 depressurization and the resultant rapid cool-down of the vessel. Advantage was taken of the scram feature which occurs when the main steam isolation valves are closed to provide for reactor shutdown so that high power operation at low reactor pressure does not occur, thus providing protection for the fuel cladding integrity safety limit."

The adverse consequences of reactor isolation occurring at reactor pressure approximately 10 psig below the specified minimum value of 860 psig is limited to those effects attendant to a greater than normal reactor cool-down 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% recirculation flow. Therefore, the consequences of a 10 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 cool-down due to the lower isolation pressure are 3

inconsequential since there is less than 2*F difference between the saturation temperature for 860 psig and 850 psig.

4 Corrective Action Continuing corrective actions being taken at this time are as follows:

1. Investigation is being conducted into the basis fo~ the steam line low pressure setting of 850 psig. Development of a Technical Specification change to lower the set point will follow if results of i transient analyses indicate this possibility.

2. Recommendations to possibly reduce or eliminate the sensor set point j change problem have been received. It was reported that General Electriu ,

tests on a pulsating line to simulate plant conditions show that pre- l cycled Barksdale switches show improvement but that the switches still 1 do not meet 1% repeatability. General Electric, therefore, recommended an Ashcroft switch as it is more accurate. The Ashcroft catalog 4

. number is 61 S 6080 BN20-06L-1028. .

O O I

Abnormal Occurrence No. 50-219/74/22 Page 3 As a result, one switch of. each type (pre-cycled Barksdale and Ashcroft) has 4

been purchased for test and evaluation at Oyster Creek. An Ashcroft switch is

. currently on hand and undergoing evaluation.

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:

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

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

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

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

5. Abnormal Occurrence Report No. 50-219/74/12 i

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.ersey Centra ;df Power & Light Company D

. MADISON AVENUE AT PUNCH BOWL ROAD

• MORRISTOWN, N.J.07960

• 201-539-6111 asunsa or rus General fjf] Public Utilities Corporation srsrsu

.c March 22,1974 [';;.f'!I.O. s

$dCy3,','rn E2 MAR 281974 0- .

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Mr. A. Giambusso Deputy Director for Reactor Projects g ['

Directorate of Licensing ,

United States Atomic Energy Commission Washington, D. C. 20545

Subject:

Oyster Creek Station Docket No. 50-219 Abnormal Occurrence Report No. 50-219/74/22 The purpose of this letter is to forward to you the attached Abnormal Occurrence Report in compliance with paragraph 6.6.2.a of the Tcchnical Specifications.

Enclosed are forty copies of this submittal.

Very truly yours.

hbWj.s(O O x/ r Donald A. Ross Manager, Nuclear Generating Stations es Enclosures cc: Mr. J. P. O'Reilly, Director Directorate of Regulatory Operations, Region I L

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