ML20084D062

AO 50-219/74/35:on 740705,main Steam Line Low Pressure Switches RE23B,C & D Found to Trip at Pressures Less than Min of 860 Psig.Caused by Switch Repeatability.Problem Under Investigation

ML20084D062
Person / Time
Site:	Oyster Creek
Issue date:	07/08/1974
From:	Carroll J, Rone A JERSEY CENTRAL POWER & LIGHT CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
50-219-74-35, NUDOCS 8304080461
Download: ML20084D062 (5)

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%j  % .a ro: Jene P. O'Failly Directorate cf Pegulatory Operation.;

Peglen I 631 Park Avent:c King of Prtcsia, Fcansylvenia 1940S i

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Pte:a: Jerney Central Pov:er f Licht Co:grTy 3

Oysta.r Crc:k Nuclear. Generating Station ,

Docket #50-219 Forketl River; New Jersey 08731 .

l Obj e ct - ALnorm1 Occurrence Report No. 50-219/74/35 The following is a prolicinary report being subultted in coeplicnce tritt. the TecJmical Specifications, paragraph 6.6.2.

Pratininary Approval: i T

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m Initi~al Tolopherto. p Dsto of 7/sj74 Occurrenceq s, 7/5/74 Reprt Dato: _

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1540 Report Date: 7/ri/74< .c _ ' ' " 0ccurrence t.-

OYSTER CREEK NUCLEAR GENERATING STATION

- FORKED RIVI!R, NHH JERSEY 09731

/unorcal Occurrenco Report No. 50-219/74/ 35 IDENTIFICKfl0M > Violation of the Technical Specifications, parar,raph 2.3.7, OF OCCURRENCfl:

Ifnin Steam Lino low Pressure Switches Pf23B, C, ::nd D.ucre found to trip at pressures less then .the etnic:tn required value of 850 psig.

This event is considdred to be ' ne abnormal occurrence as de- j fined in the Technical Specifications, paragraph 1.15A.  :

1 CGiDITIONS PRIOR Steady Stato Power P,outino Shutdown TO OCCURRENCE: llot. Steadby Operation  ;

Cold Shutdown Load Omngos During Refueling Shirtdown Routine Power Operation i I

X Routine Stortty 0ther (Specify)

Operation _ _ _

Power: Reactor,;.12.40 F4 l" w Elec., 399'lafe Flo'4 : Recirc. , 8.6 x 10 gp:2 Feed., 4.5 iit 108 1b/he Reactor Pressure: 1020 psig TESCRIPTIW OF Oa Friday, July 5,1974, at 1540, while perforcing a routino OCCURRENCE:

survoillance test on the four J Main Steam Line Low Pressure Switches, it was discovered th'at switches P.E23B, C, and D tripped at 845, 857, and 854 pslNhehp{ctiv0!y.

i Those values I are holow the rinirem 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 fotnd" cad "as loft" switch settings were:

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Abnormal Occurrence Poport No. 50-219/74/35 PO'!C 2 "As Fcund" Settin o "As Inft" Settiy a FI23A c54 psig 864 psig FI23B S45 psig E62 psig RE23C E57 psig 863 psig DB23D 054 psig 862 psig APPAPDTT CAUSE X Design Proceduro GF OCCUEENCE: 1:anufacturc Unusual Service Conditien Installation / Inc. Enviren" ental Constructica ~~

Corp;nent Failura Operator Other (Spccify)

Suitch repentability is a recogni cd prchlea and work is in j r .

progress to forr.ulato a final soluticn.

i ANALYsrG OF M indicated in the bases of the TechMen! Specifications, f CCCUPffSG:

"iho tou pressure isolotion of the !!ain Stcen Lines at E50 i

psig was provided to give protection arrinat ft:st reactor I depressurizatica und the resultmt rapid cooldewn of the vessel. Adv ntage uns tcken of the scica fonture which occurs when the M2in Stean Inolation Valves cro clor.ed to provide for reactor shutdcma so thct high power operation at Icw reacter pressure dacs not occur, thus providing protec- 4 tien for the fml cladding integrity safety lielt." g f

The adverso consequences of reactor lostation occurring at recetor presrure approxitately 15 psig beloa the s >ccified )

a vininum value of 860 psig in lic.ited to those effects atten-d1nt to a greater than norn:a1 ronctor cooldcun rato. lho 1

fuel cladding integrity safety licit only con.cs into effect I 5,

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ihnor:aal Occurrence noport No. 50-219/74/55 Pog: 3 for pwer operctica at reacter pn'snures less than 600 psig or for pser operation greater than 354 Kit with less then 10% recirculation flou. Thorufore, the connequences of n IE. psig lower then nornni reactor isolction und scrcn set-point hcs no threatening effect whatsoever on the fuel clsMin;; int egrity.

The effects of a too rapid ecoldown due to the Icwer isoln-tien presnure nre ir. consequential ninee there iq. Icss than 212 difference between the saturation terport.ture for USO 4

psig end 835 psig, i C1UJLCr1VE . C7tinuing cpunctive actions being trken Lt this tir arc

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ns staten in A5nacol Occurrence Report Hos. 74-9, 74-10, 74-12, and 74-?2, and as restnted horcin: I 4

1 Investigation is being ccaducted into the basis for the stenn line 1w pressure sett!nh of E$0 psig. Developrznt of a Technical Specification chango to lover the sotpoint will fcilou if results of trcnsient annlyses indicste this possibility. (See Ibnorcal Occurrence Hopert No. 73-39.)

2. Re.co::c:andations to possibly reduce or clininate the sensor L a

setpoint change pmblen have bocn roccived. It was re-l il '

ported thot General Electric tests on a pulenting line I to sinninto plant conditions sher that pre-cycled Dads- 3 1

dalo switches show improvecent but that tho switches still i do not rect 14 repe!!tabill ty. Gcncral Bloctric, therefore, I

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s Abnormal Occurrenco <

,Rspidt No. 50-219/74/35O *. O +'. race-4 -

recow, ended an Ashicroft switch as it is more accurate.

The Ashcroft catalog mi-ber'is 61 S 6080_ DN20-06L-1028 ,

I As a result, one switch of each type. (pre-cycled Barks- ,

I-dale and Ashcroft) has been purchased ~ for. test and ]

evaluation at Oyster Creek. An Ashcroft switch is cur-rently on hand end undergoing evaluation. 4 i -

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PA1WPE DATA: Manufacturer data pertinent to these' switches are as follows:

Heletron corp. (subsidiaryfor Darksdale) ,

i Los Angeles, Californi'a Pressure Actuated Switch Model 372' Catalog #372-6SS49A-293 Rango 20-1400 psig -

Proof Psi.1750 G 1.f Provious Abnormal Occurrence Reports involving these switches are:

1. Letter to Mr. A. Gia::busso from Mr. D. A. Ross, dated Deccre.ber 24, 1973,

2. Abnornal Occurrence Report No. 74-l'.

3. Abnormal Occurrenco Report No' . 74-0,

4. Abnorm 1 Occurrence Report No. 74-10,

5. Abnor:asl Occurrence Report No; 74-12.'

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

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MADISON AVENUE AT PUNCH BOWL ROAD

• MORRISTOWN. N.J. 07960

• 201-539-6111 General g{*, Public Utilities Corporation 4

July 15, 1974 VI A

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Mr. A. Giambusso u.ai(M www'""' q' y

Deputy Director for Reactor Proj.ects Directorate of Licensing g t.pm D3 ** ,

United States Atomic Energy Commission s N

T Washington, D. C. 20545 '

Subject:

Oyster Creek Station Docket No. 50-219 fincr= 1 00:urr:ne: ..:p;rt "

MO. 50 210/71/25 The purpose of this letter is to forward to you the attached Abnormal Occurrence Rep' ort in compliance with paragraph 6.6.2.a of the Technical Specifications.

Enclosed are forty copics of this submittal.

Very truly yours,

,uszbl ., %;

Donald A. Ross Manager, Nuclear Generating Stations es Enclosures i cc: Mr. J. P. O'Reilly, Director .

Directorate of Regulatory Operations, Region I

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a$1 Jersey Central Power & Light Company ($=f {f MADISON AVENUE AT PUNCH DOWL ROAD e MORRISTOWN, N.J.07960

• 201539-6111

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General, ', Pubhc Utahties Co,poration OYSTI!R CREEK NUCLEAR GENERATING STATION 1:0RKl!D RIVER, NEW JERSEY 08731 Abnormal Occurrence $ bMg Report No. 50-219/74/35 ' V '- f ,enlpd \p f.

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                                                                                                                            , I'j July 15,1974 i,       a    -

Occurrence Date sc / ; iN_ ? t-July 5, 1974 Identification of Occurrence Violation of the Technical Specifications, paragraph 2.3.7, main steam line low pressure switches itE23Ii, C, and D were found to trip at pressures less ti t an the minimum required value of 860 psig. 'Ihis event is considered to be an abnormal occurrence as defined in the Technical Specifications, paragraph 1 1.15A. i Conditions Prior to Occurrence The plant was in a routine startup. The major plant parameters at the time of the event were: Power: Reactor,1200 FMt Electric, 399 FMc Flow: Recirculation, 8.6 x 104 gpm I cedwater, 4.5 x 10 6 lb/hr Reactor Pressure: 1020 psig Description of Occurrence On Friday, July 5, 1974, at 1540, while performing a routine surveillance test on the four main steam line low pressure switches, it was discovered that switches RE23B, C, and D tripped at 845, 857, and 854 psig, respectively. These (e.-.~,;3 D~. f c-r (d

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Abnormal Occurrence No. 50-219/74/35 Page 2 values are 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 cocrection factor. The "as found" and "as left" switch settings were:

                                                                  "As Found" Settings                                    "As Left" Settings RE23A                                                                   864 psig                   864 psig RE23B                                                                   845 psig                   862 psig RE23C                                                                   857 psig                   863 psig RE23D                                                                   854 psig                   862 psig Apparent Cause of Occurrence 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 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 cooldown of the vessel. Advantage was taken of the scram feature which occurs when the Main Steam Isolation Valves are closed to provide the 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 15 psig below the specified minimum value of 860 psig is limited to those effects attendant to a greater than normal reactor cooldown rate. 'Ihe 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 15 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 isolation pressure are inconsequential since there is less than 2*F difference between the saturation temperature for 850 psig and 835 psig. Corrective Action

                'the corrective actions being taken at this time are:

1. l'ormal correspondence was initiated with General Electric Company on March 26, 1974 following numerous attempts at informal resolution of this problem. Since then, additional follow up conversation and correspond-ence, as recent as June 4, 1974, has ensued. General Elcetric has been

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 .   ,%, j ~                                                     p O                                    o Abnormal Occurrence No. 50-219/74/35                                    Page 3 requested to investigate the feasibility of a change to the Technical Specifications which would allow for tolerances or deviations on all instrumentation connected with safety systems and protective functions.

If this approach cannot be technically justified, General Electric has i been requested to develop a basis for a Technical Specification change to ' reduce the main steam low pressure setpoint considerably lower than the present 850 psig but with an acceptable margin to the 600 psig fuel cladding integrity limit for power operation. The above actions, if taken, will resolve the problem of the main steam line low pressure deviations. Unfortunately, the approach and response by General Electric has not been entirely satisfactory and has caused delay in our resolution of the matter.

2. The Ashcroft switch that was reported in Abnormal Occurrence Nos. 50-219/74/10, 50-219/74/12, and 50-219/74/22 to have been undergoing tests, has been found to give excellent repeatability under controlled conditions. Ilowever, under conditions similar to that presently found during the surveillance of the Barksdale switches, the repeatability of the Ashcroft switches vary within their design limitations (+ _

1** of full scale). hhereas they may be somewhat superior to the Barksdale switches, they still are unsatisfactory for the Technical Specification limiting safety system settings. Testing is continuing. Consequently, the above stated results are still considered to be preliminary in nature. l 3. 'lhe General Office lleview Board has been involved in every instance of l instrument setpoint repeatability and has assigned to the General Public i Utilities Service Corporation's Electrical Engineering Department the task of problem investigation. The item has been pursued in various General l Office Review Board meetings when appropriate abnormal occurrences have ! been discussed, and the General Office Review Doard, as well as the Plant l Operations Review Committee, is committed to following the problem to a final solution. To date, a total of thirteen abnormal occurrences have i been identified this year to be the result of instrumentation repeatability l p rob lems . Most, if not all of the setpoint inaccuracies, however, fall ! within the manufacturer stated tolerances for the instrument involved. This l implies that repeatability as such is not in questi:,n. Consequently, the preferred action identified in "1" above would appear, at this time, to be the only reasonable solution for this condition. Six of the thirteen i reports have been generated as a result of " repeatability" of the main steam line low pressure switches. In this case, the alternate action in "1" above will be pursued in the event that the preferred action is not feasibic. j Additionally, the General Public Utilities Service Corporation's Electrical Engineering Department has identified other means of monitoring this l parameter and has made recommendations to correct the problem, all of which l involve redesign of the monitoring network frem either a mechanical and/or electrical standpoint. The Jersey Central Power f, Light Company Generation Engineering Department is currently investigating with General Electric Company the feasibility of several of these alternate plans recommended by both General Public Utilities Service Corporation and the plant staff. l l l

I , . * ' ,y - r U V I i Abnormal Occurrence No. 50-219/74/35 Page 4 Planufacturer data pertinent to these switches are as follows: Ffeletron Corporation (subsidiary of Barksdale) Los Angeles, California Pressure Actuated Switch blodel 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. 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

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