ML20134B561

Event Tracking Sheet Re 930625 Event Involving Refueling Water Tank Corrosion

ML20134B561
Person / Time
Site:	Saint Lucie
Issue date:	06/17/1994
From:	Eric Benner NRC (Affiliation Not Assigned)
To:
Shared Package
ML20134B255	List: L-93-112, Forwards Safeguards Event Log Entries for Jan-Mar 1993.Encl Withheld (Ref 10CFR73.21) L-93-181, Forwards Safeguards Event Log Entries for Period of Apr-June 1993.Entries Withheld (Ref 10CFR73.21) L-93-265, Forwards Safeguards Event Log Entries for Period Jul-Sept 1993.Log Withheld L-94-016, Forwards Safeguards Event Log Entries for Fourth Quarter 1993.Log Does Not Contain Safeguards Info as Defined by 10CFR73.21 L-94-095, Forwards Safeguards Event Log Entries for Period Jan-Mar 1994.Log Entries Withheld,Per 10CFR73.21 L-94-186, Forwards Safeguards Event Log Entries for Period Apr-June 1994.Encl Withheld L-94-269, Forwards Safeguards Event Log Entries for Period Jul-Sept 1994.Encl Does Not Contain Safeguards Info Per 10CFR73.21 L-95-121, Forwards Safeguards Event Log Entries for Period of Jan-Mar 1995,per 10CFR73.71(c)(2) L-96-296, LER 96-S02-00:on 961011,failed to Terminate Access of Temporary Licensee Employee.Caused by Cognitive Personnel Error.Security Unassigned Card Key & Plant Administrative Procedure 0010509 Revised ML20134B253 ML20134B260 ML20134B469 ML20134B502 ML20134B509 ML20134B516 ML20134B520 ML20134B535 ML20134B538 ML20134B541 ML20134B549 ML20134B561 ML20134B566 ML20134B624 ML20134B629 ML20134B742 ML20134B796 ML20134B826 ML20134E919 ML20134H152 ML20134K088
References
FOIA-96-485 NUDOCS 9503010255
Download: ML20134B561 (4)

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• - OEAB EVENT TRACKING SHEET [o SSb No Sort Specified  !

QUERY > "BENNER" $ Assigned To & Assigned Date >- 06/09/94 & Assigned Date <- 06/09/94 Plcnt: SAINT LUCIE Unit: Engineer: BENNER E.

Evcnt: (p Sh Morning Report: Briefing: i 50.72#: O LER#: 050000009400000 PN#: I Other Notification:

UPRSE #94041811.7 IR 60-556/13-/8 8 sycten: 8CC6 Component: ReReig AMee Ok.

OPERATING MODE SIGNIFICANCE h-Operation A - Reactor Protection System -

2 - Startup Safety-Related Cooling System 3 - Hot Standby @G -Fuel Cladding 4 - Hot Shutdown D - Reactor Coolant Pressure Boundary 5 - Cold Shutdown E - Containment '

6 - Refueling F - Plant Power 7 - Other G - Unexpected Plant Performance H - Other: ,

CAUSE EVENT TYPE h1-EquipmentFailure SIG - Significant Event z

3 Design or Installation Error Operating Error E0I - Event of Interest D - To Be Determined

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4 - Maintenance Error - Other '

S - External l 6 - Other POTENTIAL AO: MO Criterion:

Eg er Approved: M  %

Section Leader A. Chaffee Branch Chief g EVENTS ASSESSMENT PANEL First Screening: N Closure:

significance

Description:

REFUELING WATER TANK CORROSION (SEE ATTACHED PAGE).

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ETS-02 Page:1 06/17/94 Q3, .

i 94041811.7 ST. LUCIE - Refuelina water tank corrosion

Description:

St. Lucie 1 refueling water tank corrosion could potentially prevent l having a sufficient source of borated water for the safety injection systera.

LER: None identified i 50.72: None identified I.R.: 50-335, 389/93-18 Regional contact: unspecified I

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l l DOCUMENT LOCATION & NAME: G:\EJBl\UPRSE_29.EFR l l

PSE:UPR EVENT FOLLOW-UP ASSIGNMENT SHEET ASSIGNMENT DATE: 06/09/94 ASSIGNED T0: BENNER E.  ;

i PLANT & UNIT: SAINT LUCIE. UNIT 1 EVENT DATE: 06/25/93 i 50.72 REPORT NO:  !

DAILY REPORT DATE/NO: )

l OTHER REPORT: UPRSE #940418II.7 i

.Lnspection Report 50-335. -389/93-18  !

EVENT

SUMMARY

AND SPECIFIC FOLLOW-UP ASSIGNMENT f REFUELING WATER TANK CORROSION (SEE ATTACHED PAGE). f DETERMINE DETAILS, PREVIOUS DISPOSITIONS (IF ANY), RISK SIGNIFICANCE (If I PRACTICAL), PREVIOUS SIMILAR EVENT DISPOSITIONS, AND ENFORCEMENT ACTIONS.

PROPOSED EVENT CLASSIFICATION AND EVALUATE THE NEED FOR GENERIC COMMUNICATION.  !

INCLUDE THE NUMBER OF HOURS SPENT ON THIS ASSIGNMENT TN THE CLOSE0UT.  ;

CIRCLE THE APPLICABLE CASE:

SAFETY SIGNIFICANCE CLASSIFICATION: OTH YES E01 NO SIG NO A0 N0 t t

GENERIC CONCERN STATUS: NO IN # BUL # GL#

i OR BRIEF: NO # [

CLOSE0VT l While operators were performing a log data review, they identified a slow loss  !

of water inventory from the 525,000 gallon refueling water tank (RWT) ,

(Technical Specification minimum is 400,000 gallons). RWT water inventory had  !

begun to drop by about 0.6 to 1.5 gpm on about June 15, 1993. The leak was l nearly constant during the period of discovery and repair. It was determined that a total of about 55,000 gallons leaked befnre the leak was repaired. The cause of the leakage was a 5-mm hole corroded into the bottom of the RWT. 1 Inspections found no indications of major tank integrity problems. The licensee repaired the RWT by epoxying an aluminum plate over the hole on July >

17, 1993, and intends to institute a more permanent repair at a later date.  ;

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The analysis by PNL addressed the potential for a minor leak such as the one experienced (1.5 gpm), and also evaluated the potential for an RWT rupture (100 gpm, maximum makeup capability to the RWT). The risk assessment estimated an increase in core damage frequency (CDF) of 4.4% for the 1.5 gpm leak, and 0.5% for the 100 gpm rupture. These estimated increases in CDF assume that RWT tank repairs are ineffective due to corrosion within t'-

! remaining life of the plant. RWT level is indicated and annunciated in the control room, as well as being subject to a shiftly surveillance. )

The evaluation also indicated that if the RWT does leak, it is highly likely that the plant staff will be effective in maintain',ng adequate RWT level pending completion of repairs. l This event is classified as OTHER. Approximately three hours (in addition to

resources spent by PNL) were spent on this assignment.

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