ML20085C890

AO 50-254/74-35:on 741025,pressure Suppression Chamber Water Level Exceeded Tech Spec Limit.Caused by Personnel Error & Instrument Drift.Level Transmitter LT-1-1626 Recalibr & Note Covering Methods Forwarded to Personnel

ML20085C890
Person / Time
Site:	Quad Cities
Issue date:	11/04/1974
From:	Kalivianakis N COMMONWEALTH EDISON CO.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
References
AO-50-254-74-35, NJK-74-369, NUDOCS 8307130189
Download: ML20085C890 (3)

Text

c- . .

't

, e, Commond*alth Edisen

/~ '

Ouad-cit <cs Generating s: anon

~,

1 29 Post O!hte Box 216 " ,'-

( 'y <,p cordOva, libnois 61242 ,j

%" Tofcphene 309/654-2241 , " N'

' >N November 4, 1974 3

[

- /(/ [h ef) ll0 y g 70 74 ,

cs, ,, ,

NJK-74-369 0, 9 7 : ,. , ' ' . _

.y;7.>;' [,

Mr. John F. O' Leary, Director Directorate of Licensing Regulation U. S. ATCHIC ENEIGY COPJilSSION Washington, D. C. 20545 HEFEIENCE: QUAD-CITIES NUCLMR P0' DER STATION Docket No. 50-254, DPR-29 Appendix A, Sections 1.0.A.2, 3 7.A.l.b, 6.6.B.l.a.

Dear Mr. O' Leary:

Enclosed please find Abnormal Occurrence Report No. A0-50-254/74-35 for Quad-Cities Nuclear Power Station. This occurrence was previously reported to Region III, Directorate of Regulatory Operations by tele-phone on October 25,197h and to you and Region III, Directorate of Regulatory Operations by telecopy on October 25, 1974.

This report is cubmitted to you in accordance with the requirements of Technical Specification 6.6.B.1.a.

Very truly yours, COVM0?TdEALTH EDISON COMPANY QUAD-CITIES NUCLEAR P0' DER STATION

~p',f,-

(3-f / /, .; , . % ~ - W-~

t _

N.'J. Kalivianakis Station Superintendent NJK/EAS/dkp Enclosures cc: Region III, Directorate of Regulatory Operations J. S. Abel 8307130189 741104 DI Mgf PDR ADOCK 05000254 p S PDR Sh

. l@lysashion M. ,

O O ,

REPORf NUISER: 50-254/74-35 REPORf DATE: Novcober 4, 197t OCCURRENCE DATE: October 25, 1974 1

FACILITY: Quad-Citics Nuclear Power Station Cordova, IL 61242 l IDENTIFICATION OF OCCURRENCE:

l Pressure Suppression Chamber water level execcded limit.

CONDITIONS PRIOR TO OCCURRFXCE:

Unit 1 was operating at 762 MWe. Monthly and quarterly surveillance tests for the High Pressure Coolant Injection system and the Reactor Core Isola-tion Cooling systcm had just been completed.

DISCRIPTION OF OCCURREl'CE:

After the tests had been ecmpleted at 2:00 a.m. on October 25, 1974, the suppression chamber level was indicated in the cont,rol room to be between two and two and one-half inches. The reason that the level was allowed l to reach this point was due to a control room operator error in failing to maintain proper suppression chamber water level during the tests. While valves were being aligncd to pump the water level down, it was noticed that the High Pressure Coolant Injection (HPCI) pu p suction valves MO-1-2301-35 and MO-1-2301-36 from the suppression chamber had opencd and that the suc-tion valve from the condensate storage tank, E0-1-2301-6, had closed. These valves align in this manner when the suppression chamber level reaches five inches as given by float-type level switches LS-1-2351 A and B. At first it was thought these valves had aligned at an improper level and at 5:30 a.m. the control room operator started to pump the excess water frcm the suppression chamber to the waste collector tank. He finished this opera-tion at 5:45 a.m. Later in the corning it was determined that the float switches which change the HPCI suction valve line up were functioning properly. The problem was found to be a malfunction of level transmitter LT-1-1626 for the level indicator in the control room. Because of the in-correct indication, the water level in the suppression chamber had been t.ctually raised to a maxitum of five inches. Technical Specification 3 7.A.l.b requires that the maximum water level in the suppression chamber at normal power operation not excced two inches.

~

DESIGNATION OF APPARE!IT CAUSE OF OCCURRENCE:

Operator Error - The primary apparent cause is due to operator error; how-ever, a contributing factor to this occurrence was instrument drift caus-ing level transmitter LT-1-1626 to be approximately two inches out of calibration. The control rocm operator believed his instrument and so allowed the level to increase enough to cause the HPCI suppression chamber

l

)

G

.- u l suction valves to open. The reason for this large amount of water being placed in the euppression chamber was due to testing the HPCI and RCIC syste:ns in succcssion.

ANALYSIS OF OCCURRECE:

It is not exactly known how long the level transmitter had been cut of calibration. The last date it was calibrated was August 30, 1974. In no way was the health and safety of the public jeopardized by this occur-rence. The contaminated condensate storage tank level was not abnormal at any ti&. RCIC was not made inoperational. HPCI was ccmpletely oper-able at all times and the HPCI suction valvo change over did occur at the proper level. All other ECCS systems were available throughout the occurrence. Reactor operation was not affected in any way.

CORRECTIVE ACTION:

As soon as the problem was correctly identified, the level transmitter LT-1-1626 was recalibrated. At 1008 a.m. on October 25, 1974 the con-

, trol room operator began to pump the excens water to the hot well. At 11:50 a.m. the suppression chamber water level was returned to zero inches on the indicator. A note was transmitted to Operations Personnel covering the necensity and methods of maintaining the pressure suppres-cion chatber water level within the limit during HPCI cnd RCIC sur-veillance. A revision has been added to the HFCI operability test pro-cedure which will require that the water level be lower than one inch before beginning the test,. A modificat, ion has been approv(d which will install a sight glass on the suppression chamber to aid in keeping this transmitter correctly calibrated. Another modification for the installa-tion of a wide-range level transmitter has been approved that can be used to verify the indicated control room reading.

PAIIp,RE DATA:

The 1ctel transmitter LT-1-1626 is a Barton model 352 Bellows type. A previous failure with regards to this transmitter occurred on !! arch 21, 1974 and vas reported to you on March 29, 1974 As a result of this occur-rence, monthly calibrations were initiated and continued for a six-month period. No abnormalitics were observed during these calibrations. This transmitter is now calibrated quarterly,in accordance with Technical Speci-fication Table 4.2.2, and calibrations will continue on that basis. The

- new nodLfications which have been initiated will serve to prevent future recurrences of this problem.

J