ML20085G186

Ao:On 730925,trip Setpoint of 152 Inches for HPCI Flow Switch DPIS 3-2353 Exceeded Tech Spec Limit.Caused by Locking Device Failing to Control Setpoint Drift.Switch Setpoint Changed & Calibr Frequency Increased

ML20085G186
Person / Time
Site:	Dresden, Browns Ferry, 05000000
Issue date:	10/24/1973
From:	Worden W COMMONWEALTH EDISON CO.
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085G173	List: ML20085G186 ML20085G188
References
NUDOCS 8308240360
Download: ML20085G186 (2)

Text

' y wie r nu n wunm mra. umtap, ymnois

• h v if7 Address Rco'y to: Post Offico Box 767 *

, Chica knois 60690 50-249 WFW Ltr.#797-73 Dresden Nuc1 car Power Station R. R. #1 ,

Horris, Illinois 60450 ggo, g _

, October 24, 1973 ^

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) ?- 4 O Mr. A. Giambusso -

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Deputy Director for Reactor Projects Directorate of Licensing '

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U. S. Atouic Energy Cornisaion # #

Uashington, D. C. 20545 C

SUBJECT:

LICENSE LPR-25, DRESDEN NUCLEAR PO'JER STATION, UNIT #3,

_SECTION 6.6.C.1 C- .

t .C2::IC.\L SPECITIC' TIC::S.

~

_IIPCI STEMI LINE HICH FLC'J S*JITCH GUT OF CiLIBRATION.

References:

1) Dwas: P&ID M-51. S&L.12E2527

Dear lir. Giambusso:

Thic letter is to report a condition relating to the operation of the unit at about 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br /> on 'eptember 25, 1973. At this ti=e high pressure coolant injcetion (HPCI) fiow switch DPIS 3-2353 was found to have a trip cetpoint of 152.0" H 0. 2 This setpoint is contrary to Table 3.2.1 of the Technical Specifications which require a setpoint of $ 150" H2 0.

) _

PROBLEM ,,

At the ti=e of the occurrence, Unit 3 was operating in a steady state condition with a thermal load of 2295 if4c. Routine surveillance was being perfor=cd by the Instrument Depart =cnt when HPCI flow switch DPIS3-2353 was found to have a setpoint of 152" H20. The switch was ic=cdiately reset,to 148" H 2 0..

The function of DPIS-3-2353 is to isolate the HPCI .

. . * . s'tcam"s'upply 'line 'in the event *of a brsak *in' the at' cats ' piping. * * * "

INVESTICATIO'i

• The subject flow switch is a Barton model 288 differential pressure sensor. This suitch has had a tendency to drift in both~ the iticrcasing~ndd ' '

decreasing direction. A locking device was installed on the switch in February of 1973 fn an atte=ot to climinate the drift tendency. At the present ti=e. the data froa previous surveill.nnees reveals that the locking device has act solved the drift problem. The overall problem of instrument -

setpoint drift is presently under investigatien. The problem has plagued the station since its beginning, and no adequate corrective action has been determined at this time. ~

8308240360 731106 =

PDR S

ADOCK 05000259 (

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PDR

.. October 24, 1973 O Q from the manufacturers of the various drif ting sensors.The most rece Earton In the case of the service codel engineer258,visit the factory representative has recc== ended that a field to application, factory adjusteents, and calibrationThe technique.the Barton stati

/ representative tio,ns. has visited the Station and we are now awaiting his recc=cenda-

~

CORRECTIVE ACTION The immediate corrective action was to change the setpoint of DPIS-3-2353 to bring it within the Technical Specifications. The calibra-tion frequency for this switch will be increased to once per conth until cuch time as this switch has demonstrated its reliability. Additional corrective service engineer. action will be based on recc=mendations made by the Barton field EVALUATION Flow switch DPIS-3-2353 is one of two flow switches that isolate the HPCI steem line in the event of a break in the steam piping. The second switch *is DPIS-3-2352, and its setpoint at was 146" H2 0. the time of the occurrence Therefore, it is concluded that in the event of a break in the HPCI steam line piping, isolation would have occurred well within the Technical specifications, and thus the safety of the station personnel and the general public was in no way cenpromised. The continued operation of

. the unit was considered safe.

Sincerely, o I

. T. . hb W. P. Worden l Superintendent

. . -. . WFW;do , .

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TENNESSEE CHATTANT VALLEY AUTHOP1TY t q GA, TENNESSEE O

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October 26, 1973 Er.m 3 *g

~,[M Te ANN'thC S$nEPs

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O; , 007s01973 ,;4

, y j Mr. dohn F. O'Ieary ,

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l. Directorate of Licensing Office of Regulation i -

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U.S. Atomic Energy Cc mission \!['k (($$ D Washington, DC 20545 y,Q 9

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Dear Mr. O'Irary:

l TENESSEE VALLEY AUTECRITY - BRCWS FERIf NUCIIAR PLAI T UNIT 1 -

DOCET ::O. 50-259 - FACILITY OPERATI::o LICE:;SE DPR AB30FMAL OCCURRS:!CE REPORT BFAO-732TJ -

l The purpose of this report is to provide details concernin5 T,he

, l malfunction of recirculation jet punp riser d/p switch PdIS-68-24 in unit 1 at Browns Ferry I~uclear Plant on October 16, 1973 This l

! occurrence was reported by telegram on October 17 to the Region II 1

Directorate of Regulatory Operations, Atlanta, Georgia.

I .

Ibscription of the Incident During routine surveillance testing'on October 16, recirculation jet pump riser d/p svitch PdIS-68-24 was found to operate outside the technical specification setpoi;1t of greater than 0 5 but less than 1 5 psid as specified in table 3 2.B. The as-found setpoint was 1.8 psid.

j. Investigation and Corrective Action i

Each of the four differential pressure switches operate relays whose contacts are arranged in a one out of two taken tvice logic in the RER injection circuit.

The minimum number of channels required for each trip system is two. The other tuo channels vere tested, found to i operate satisfactorily, and, if recuired, would have perfon: icd their intended function. The reactor was in the hot standby condition.

. These switches are Barton model 288 differential pressure switches. N ' - --

The switch nechanisms vere inspected for binding misalign=ent of other i

irredularities.

Hone was found. The ct. itches were recall' crated and then functionally tested reveral times to ensure repeatability. A functional testing frequency of cace every 2 vechs has been initiated claps modinMfI qQ , / - 1 n n. '

= . . . . .

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2 -

Mr. John F. O'Irary -

October 26, 1973 -

TEICESSEE V.illT AUTHORITY - ERO'.7::S FERRY !!UCLEAR Pill.~2 U:IIT 1 -

' DOCKET -:!O. 50-259 - F.*.CILITY OPERATI::0 LICE:?SE DPR AE::03AL OCCURRE::CE b?AO-732TJ 1

'for all four switches and vill be continued until three consecutive tests prove ratisfactory performanec. At that tiac, the original test schedule of once a month will be recu.ed. Ue intend to install, as soon as possible upon receipt, new lockinc_ A--ruitcholate c.csem'clics recently made availa' ole .by r t.he

-- vend.o.r m.- to Drevent cettoint drif t.

j Very truly yours, -

/? /

l l TENNESSEE VALLEY AUTHORITY l Q'

, cr//. e .

l

8 @ E. F. Thonas Director of Poyer Production s

CC: Mr. Nozcan C. l'oseley, Director Region II Regulatory Cperations Office, USAIC 230 Peachtree Street, :N.

Atlanta, G.eorgia s 30303 a

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