ML13246A382

Email from M. King, NRR to R. Kendzia, NRO and J. Robles, NRR FW: Wolf Creek Event Followup on EN 47590 - from Ioeb Clearinghouse Screening Summary for Tuesday, January 17, 2012

ML13246A382
Person / Time
Site:	Wolf Creek
Issue date:	01/19/2012
From:	Mark King Office of Nuclear Reactor Regulation
To:	Thomas Kendzia, Robles J Office of New Reactors, Office of Nuclear Reactor Regulation
References
FOIA/PA-2013-0273
Download: ML13246A382 (2)

Text

M Robles, Jesse From: King, Mark Sent: Thursday, January 19, 2012 7:10 AM To: Kendzia, Thomas; Robles, Jesse Cc: Haskell, Russell

Subject:

FW: Wolf Creek event followup on EN 47590 - from IOEB Clearinghouse Screening Summary for Tuesday, January 17, 2012 RE: EN 47590 - WOLF CREEK: NOTIFICATION OF UNUSUAL EVENT (NOUE) AND REACTOR TRIP DUE TO LOSS OF OFFSITE POWER UNUSUAL EVENT Tom, Thanks for the feedback ... Yes- we agree... we had marked this item "continue to follow- (i.e., get more info)" and hopefully the Region will follow-up closely.., have heard the decision on their reactive inspection but I think they will end up doing one for this event (note: initial preliminary reports were it was in the SIT/AIT overlap region).

Jesse... we need more info on this event.., can you find out more details... see email below. I believe Wolf Creek and Callaway are both SNUPs plants similar design/layout... may want give Callaway a heads up too.

Russ if you already have more info be sure to pass it on to Jesse.

This may make a good OpE COMM or perhaps even an IFR item/ IN may be needed. Investigate this event and let me know what you recommend. Region /RI staff should be following up on the design aspects and any performance deficiencies, hopefully. Thanks, Mark From: Kendzia, Thomas Sent: Wednesday, January 18, 2012 5:54 PM To: King, Mark

Subject:

RE: JOEB Clearinghouse Screening Summary for Tuesday, January 17, 2012 Mark, In the Wolf Creek event it seems there may be a design issue with the sump pump affected by the TDAFW pump steam discharge. It would not seem as if a loss of offsite power should affect those pumps ifthey are needed when TDAFW running since TDAFW is for loss of power. I am not sure ifthe assignments cover that aspect.

Thanks, Tom Thomas A.Kendzia, PE, SRO Reactor Operations Engineer Quality and Vendor Branch 1 (AP1000/U.S. APWR)

Division of Construction Inspection & Operational Programs Office of New Reactors, U.S. NRC Office 301-415-8155 Cell F(b)6)

8) EN 47590 - WOLF CREEK: NOTIFICATION OF UNUSUAL EVENT (NOUE) AND REACTOR TRIP DUE TO LOSS OF OFFSITE POWER UNUSUAL EVENT - (NOUE TERMINATED)

See EN text: (Additional information) unit is currently in a stable condition (MODE 5). Unit obtained a safe shutdown condition and is currently stable in (MODE 5). Region performing an MD 8.3 reactive inspection risk 1

e&valuation. The following is a list of post trip occurrences:

'Root Cause not well defined (licensee continues to investigate)

-Both 'A' & 'B' EDGs started/assumed safety loads

'Decay heat removal via ASDs (atmospheric steam dumps)

'Pressurizer PORV actuation (Residents following up on this indication)

• MDITDAFW Pumps functioned as expected

'Essential Service Water (ESW) system experienced water hammer then subsequent leak in Containment Cooling (C) system

'Containment cooling issue impacted 2 channels of source range detection (counts not tracking)

• Emergency mod to cut hole in Chemistry Building bulkhead to route power cable to restore Chem Lab (facilitated Boron sampling)

• Emergency mod to cut hole in Aux Building bulkhead to route power cable to sump pump (sump over flow due to TDAFW steam discharge line)

'Condensate Storage Tank (CST) makeup challenges when available Diesel Driven Fire Pump failed to operate (Fire Truck staged as standby)

'Facility lighting running on backup/emergency power

'Train 'A' (vital) buses restored 1/2 hours after trip ('A' EDG secured)

'Train 'B' (vital) buses supplied via 'B' EDG

"'B' EDG air start (compressors) loss of power (EDGs remained functional)

"'B' EDG experienced a ground indication which cleared (Residents following up)

-Switchyard: Three offsite (345 KV) lines remained functional (grid not suspected as initiator)

'Switchyard: Startup Transformer (SUT) oil samples were normal

'Switchyard: Startup Transformer (SUT) oil samples were normal

'Switchyard: 345 KV breaker (60)/cabinet damage

'Switchyard: 345 KV breaker/switch board inspections ongoing

-Switchyard: Work being performed on Unit Auxiliary Transformer (UAT) to backfeed 'B' buses; projected to be completed today (1/17)

'Switchyard: Event recorder to track switchyard transients out of service at time of event Forward to TRG Leads for Electrical Systems (Mathew~olfgangcP l&C (Rahn), SSW/UHS (Purciarello), EP (Schrader): assigned to Russ Haskell.

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