Event Notification Report for July 23, 2015

OKLAHOMA AGREEMENT STATE REPORT - TROXLER GAUGE DAMAGED AT CONSTRUCTION SITE

The following information was received from the State of Oklahoma via email:

"A Troxler Model 4640 gauge has been struck by a vehicle at a road construction site about 5 miles south of Guymon, OK. We will provide more information as it becomes available."

The status of the source or damage to the gauge was unknown at the time of the report. A Troxler 4640 gauge typically contains 8 milliCi of Cs-137.

OFFSITE NOTIFICATION DUE TO SODIUM HYPOCHLORITE SPILL

"At 1120 EDT on 07/23/2015, while performing Chemistry rounds, a Chemistry Technician discovered an underground leak near the Plant Service Water bleach moat. The Plant Service Water bleach injection pumps were secured at 1130 EDT on 07/23/2015. The leak was later confirmed to be bleach. Approximately 200-300 gallons of 12.5% sodium hypochlorite are estimated to have leaked out of a broken underground pipe. This amount exceeded the reportable limit [100 lbs. or 80 gallons] as specified by the National Response Center. The bleach leaked into the surrounding soil and into a Plant Hatch storm drain where it pooled before reaching the Altamaha river. No bleach discharged into the river.

"Cleanup began immediately by neutralizing the bleach with sodium bisulfite and is still on-going.

"Plant Management authorized Southern Nuclear Company Environmental Affairs to report to the US Coast Guard National Response Center at 1305 EDT on 07/23/2015 in accordance with corporate procedures. The event was reported to the National Response Center at 1316 EDT. The Georgia Environmental Protection Division was also contacted.

"This event is reportable under 10 CFR 50.72(b)(2)(xi) as an event or situation related to the protection of the environment for which a notification to other government agencies have been made.

"NRC Resident Inspector was notified at 1530 at 07/23/2015.

"CR [Condition Report] 10099779"

AUXILIARY FEEDWATER MANUAL START DUE TO LOSS OF MAIN FEEDWATER PUMP DURING PLANT COOLDOWN

"During plant cooldown in response to conditions reported to the NRC in Event Notification 51253, Callaway was in Mode 3 (Hot Standby) and on the way to Mode 5 (Cold Shutdown). In accordance with cooldown procedures, Callaway was operating with one Main Feedwater Pump when the pump speed unexpectedly lowered to 0 RPM. The pump was manually tripped in response to the condition. This led to a decrease in water level in the steam generators. In response, operators manually activated the Auxiliary Feedwater System. All systems and components functioned normally in response to the event, and plant operators are currently continuing the controlled shutdown from Mode 3 to Mode 5. Safety related buses are receiving normal off-site power and the grid is currently stable."

"The NRC Resident Inspector was notified."

INITIATION OF PLANT SHUTDOWN DUE TO RCS LEAKAGE

"On July 23, 2015 at 0115 [CDT], Callaway Plant initiated a shutdown required by Technical Specifications (TS). At 2139 [CDT] on July 22, 2015, TS 3.4.13 Condition A was entered due to unidentified RCS leakage being in excess of the 1 gpm TS limit. The leak was indicated by an increase in containment radiation readings, increasing sump levels, and decreasing levels in the Volume Control tank (VCT).

"A containment entry identified a steam plume; due to personnel safety the exact location of the leak inside the containment building could not be determined.

"At this time radiation levels inside [the] containment are stable and slightly above normal. There have been no releases from the plant above normal levels.

"The [NRC] Senior Resident Inspector was notified."

* * * UPDATE PROVIDED BY ROB STOUGH TO JEFF ROTTON AT 1757 EDT ON 07/23/2015 * * *

"Callaway entered TS 3.4.13 Condition B at 0053 [CDT on July 23, 2015] for the subject leakage since reactor coolant pressure boundary leakage could not be ruled out by visual inspection. The estimated leak rate when the decision was made to shut down the plant was approximately 1.8 gpm. The plant entered Mode 3 at 0600 CDT.

"Additionally, at approximately 1315, it was determined that the duration of the required outage would be greater than three days, thus requiring notification to the Missouri Public Service Commission. This offsite notification is reportable to the NRC [per 10CFR50.72(b)(2)(xi)], and the above table has been updated to reflect this reporting requirement."

The licensee notified the NRC Resident Inspector.

Notified R4DO (Gepford).

* * * UPDATE FROM RICHARD HUGHEY TO VINCE KLCO AT 0728 EDT ON 7/26/2015 * * *

"Clarification to the initial event notification: the term 'RCS' used above means 'Reactor Coolant System.' Therefore the second sentence from the initial notification is clarified to read, 'At 2139 [CDT] on July 22, 2015, TS 3.4.13 Condition A was entered due to unidentified Reactor Coolant System (RCS) leakage being in excess of the 1 gallon per minute (gpm) TS limit.'"

The licensee notified the NRC Resident Inspector.

Notified the R4DO (Gepford).