05000423/LER-2008-005
| I .2. Docket I� � 6. Lernumber 3. Page | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(v)(C), Loss of Safety Function - Release of Radioactive Material 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 4232008005R01 - NRC Website | |
1. Event Description:
With the ,plantin Mode 6 at 0%power on November 5„2008 operators discovered .thata valve [V] (3FWS*V861) relied upon to be closed to Meet technical- spebftation requirements during fuel movement in containment was not fully closed. Plant Technical Specification (TS) 3.9.4:c requires thateaCh penetration providing direct access from the containment: atmosphere to.the outside'atmosplwrelpe Closed:by an'isolation valve, blind flange, or manual valve orbe capable of being closed under administrative control during movement of'fuel within the containment: building: Valve 3FWS*V861 is a draintine isolation valve off the feedwater:[&1] line to the "C" steam generator jSG]:inside:cdritainrnent and was:being credited.as-closed sine a pathway:to atmosphere outside cOntainment existed due to,Maintenance activities.on.associatedportionS of the main.steam syttem. The subsequent investigationideterrnined that the valye,'hadbeen in this condition during.fUel Movement:inside containment thatoccurredfrom NoyeMber 1, 2008 at 0430"until :Novernber.3„2008 at 0915.
Since the plant was in a configuration'not allowed by theteChnical specifications, inis,event is reportable in accordance.ith 10 CFR 50.73(a)(2)(i)(B) asany operation or tondition'prOhibited:by the'plant's technical 'specifications.' This is a supplement to"1..-ER 2008:005700 to:report this condition in aCcordancewith 10 CFR 50.73(a)(20)(C).
2. Cause:
Subsequent to maintenance activities on the se.condarysidebf the "C" steam generator, operators` proceeded to fill:the steam generator. Operators identified that containment sump � were-rising and found that valve 3F.VVS*V861 was the source. Operators attempted to further close' the`,and wereoot initially successful until additionatmechanicalteveragewas applied.
Thecause of this condition was determinedlo:betacorribination-ofrnechanical and.phySical factors making the valve � to operate to ensure full closure. The'packingon this valve was very tight and the ;valvehandle has an extension necessary to clear an interference. The extent of condition review identified that a valve in series;ith 3EWS*V861 (3FWS*V862) is subject to similar medhanical and design factors:and was,also not fully closed. (3FWS*V862 was 'not,being credited for compliance with IS 3.9.4.c.) 3. Assessment of,Safety Consequences:
This condition is judged to be of very,low safety significance. The reqUirementston containment penetration closure and Operability ensure that a release of radioactive material within containment to the environment will be minimized: The fuel handling accident analyses assume that during a fuel handling accident some of the fuel that is dropped and some of the fuel impacted. upon is damaged. Containment penetrations, including the personnel access hatch doors and equipment access hatch; can be open during the'movement of fuel
- provided that sufficient administrative controls are inplace such that any of these Containment penetrations can be'closed within 30 minutes. Following a' Fuel Handling Accident, each penetration, including the equipment access hatch, is closed such that a containMent atmosphereboundany can be eStablished. The containment atmosphere boundary is establiShed whenany penetration Whichprovides direct access to the outsideatmosphere is closed such that atjeast one barrier between the containment atmosphere and the outside atmosphere is-established. Thedesignbasis Fuel Handling 'Accident does not credit closure of containment and assumes all radioactivity released as part of the accident is exhausted directly to the :environment within 2:hours. Under design basisconditions, offsite dose and dose to the control ,room operators are within regulatory limits.
In this case, a pathway to.atmosphere existed'via a hose connected to a,2" valve-(3fWS*V861), ,through the feedwater line to the secondary side of the "C" steam generator, through the.main steam line and to atmosphere through an open main steam isolation valve drain standpipe low:point drain (3DTM*V1I7). Since operators were not aware that 3FWS*V861 was'not fully closed, no administrative controls were in place to ensure the penetration could be closed within 30 minutes. This condition existed Irom November 1, 2008 at 0430 until November 3, 2008 at 0915, the period of time in which .fuel movernent:inside containment was underway. There was !no fuel 'handling accident.
4. Corrective Action:
Valve 3FWS*V861 and 3FWS*V862 were subsequently closed. Maintenance was performed on both:of tbese valves during 'refueling outage 3R13 '(Spring 2010). Properoperation of both valves was validated through !post maintenance testing.
5. Previous Occurrences:
No previous similar events/conditions wereidentified.
Energy Industry IderitificationSystem (EDS) codes are identified in the textas [XX).