Event Notification Report for April 05, 2012

TROXLER MOISTURE DENSITY GAUGE FOUND ON INDIAN RESERVATION

The Bureau of Indians Affairs Great Lakes Agency (License #48-32735-01) reported that a Troxler Moisture Density Gauge has been found on the Bad River Indian Reservation. The gauge was delivered to the Radiation Safety Officer for the Bureau of Indian Affairs. The gauge is currently stored in a safe location and the source rod is in the locked position. The licensee and owner of the gauge is not known at this time. The Troxler Gauge is a model 3411B, S/N 8975, and contains an Am-241 40 mCi and a Cs-137 7.5 mCi source. The RSO contacted the Troxler Corporation for more information.

THIS MATERIAL EVENT CONTAINS A "LESS THAN CAT 3" LEVEL OF RADIOACTIVE MATERIAL

Sources that are "Less than IAEA Category 3 sources," are either sources that are very unlikely to cause permanent injury to individuals or contain a very small amount of radioactive material that would not cause any permanent injury. Some of these sources, such as moisture density gauges or thickness gauges that are Category 4, the amount of unshielded radioactive material, if not safely managed or securely protected, could possibly - although it is unlikely - temporarily injure someone who handled it or were otherwise in contact with it, or who were close to it for a period of many weeks. For additional information go to http://www-pub.iaea.org/MTCD/publications/PDF/Pub1227_web.pdf

UNPLANNED SYSTEMS ACTUATIONS WHILE PERFORMING A SURVEILLANCE TEST

"Unit 1 was performing a planned refueling outage surveillance test, FNP-1-STP-40.0, 'Safety Injection with Loss of Off-Site Power [LOSP].' The systems were being returned to normal following the actuation portion of the test. When the B1F Sequencer Test Trip Override Switch was taken to the 'ON' position, the 1-2A Diesel Generator output breaker opened, which caused a loss of power to the 'A' Train 4 kV busses. Prior to the event, the 1-2A Diesel Generator was running at normal speed and voltage carrying the 'A' Train 4kV busses. When the diesel generator output breaker opened, it then reclosed upon receipt of the LOSP signal causing the LOSP sequencer loads to automatically start. This included the 1C Component Cooling Water Pump, the 1A High Head Safety Injection Pump (discharge isolation was closed prior to the event), and the 1A and 1B SW pumps. Therefore, during the test, the system actuated in a way that was not part of the planned surveillance testing. The 1A RHR pump was in shutdown cooling mode at the time of the event and was load shed. RHR was restarted manually by the operating crew approximately 1 minute later (no auto start [signal] present due to a loss of site power - LOSP signal without a safety injection signal present).

"The investigation revealed that a step in the procedure sequence was not performed during the restoration portion of the test. The operator did not parallel the diesel with off-site power prior to operating the B1F Sequencer Test Trip Override Switch which opened the diesel output breaker without off-site power aligned to the 'A' Train 4kV busses. The 1-2A Diesel Generator was subsequently paralleled to the grid and properly shutdown per the test procedure restoration."

The licensee notified the NRC Resident Inspector.

STANDBY SHUTDOWN FACILITY (SSF) NOT ANALYZED FOR ALL OPERATING CONDITIONS

"On 3/29/2012 Duke Energy identified that unanalyzed conditions exist for SSF mitigated events since associated thermal and hydraulic analyses do not consider all initial operating conditions, especially lower operating modes and lower decay heat. Specifically there are four (4) conditions where the SSF is not currently analyzed:

"1. SSF operating at less than 525 degrees F and less than normal operating pressure (approximately 2155 psig),
2. SSF operation before four (4) Effective Full Power Days (EFPDs),
3. SSF reactor coolant make up at low Reactor Coolant System (RCS) pressure.
4. A reactor trip from less than 85 percent power and less than 579 degrees F.

"On 4/4/2012, an immediate determination of operability concluded that for the first three (3) conditions the SSF was operable but degraded/nonconforming (OBDN). For the 4th issue, there was reasonable assurance that 1% delta k/k shutdown margin would be maintained if T average. remained above 500 degrees F. Based on a lack of analysis and an increased likelihood of reducing T average. below 525 degrees F during a 72 hour event, the SSF was declared OBDN with a separate operability determination required to validate the Unit 3 power coastdown and end of life T average. reduction analysis. Until additional analysis is performed, the SSF is inoperable on any unit where the power level is reduced below 85 percent.

"A second operability determination for Unit 3 concluded that the SSF will maintain greater than or equal to 525 degrees F with an initial power level of 70 percent and a 570 degree F T average. The SSF will be declared inoperable on Unit 3 if power is reduced to less than 70 percent. Seventy percent was chosen as a conservative value to ensure the unit stayed inside the bounds of existing analyses. Unit 3 is currently at approximately 85 percent power and reducing power at approximately 1 percent per day in preparation for the Unit 2 end of core 26 refueling outage. For Unit 3, the SSF is OBDN based on preliminary calculation results.

"On 4/5/2012, due to a worsening component cooling water system leak on Unit 2, it was necessary to bring the unit down to Mode 3 to implement repairs. Upon down power, when Unit 2 transitioned below 85 percent power, the ability of the SSF to perform its design function, in consideration of the information above, could not be confirmed and the SSF was declared inoperable for Unit 2.

"Currently, there is no conclusive information that would support SSF operability while Unit 2 is below 85 percent power. As such, this event is being conservatively reported under 50.72(b)(3)(ii)(B), 'The nuclear plant being in an unanalyzed condition that significantly degrades plant safety.' Due to their current power levels, this condition does not affect Units 1 and 3.

"Initial Safety Significance: Until confirmed by analysis, the lack of decay heat may result in an initial over cooling of the RCS and potentially an interruption of natural circulation or inadequate shutdown margin. Consequently, the SSF was declared inoperable.

"Corrective Action(s): Additional analyses are being completed to reestablish SSF operability to bound the unanalyzed entry conditions.

"The NRC Resident Inspector has been informed."

* * * UPDATE FROM DEAN PORTER TO JOHN KNOKE AT 1403 EDT ON 04/13/12 * * *

"Update to ENS Notification Number 47810: ENS Notification number 47810 identified an unanalyzed condition for Oconee Unit 2. This update includes Oconee Units 1, 2 and 3 because the condition of the SSF affects all three units during certain plant conditions.

"The Standby Shutdown Facility (SSF) serves as a backup for existing safety systems. Currently the events that rely upon the SSF for mitigation are unanalyzed on Units 1 and 2 when the power level is reduced below 85 percent and on Unit 3 when the power level is reduced below 70 percent, or for any unit operating with less than 4 Effective Full Power Days (EFPDs) at 100% full power since its most recent shutdown. Since the SSF events are unanalyzed for these conditions and until further analysis and evaluation can be completed, Duke Energy is conservatively calling the SSF inoperable when in these conditions.

"For these conditions, this event is being reported for Oconee Units I, 2, and 3 under 50. 72(b )(3)(ii)(B), that is, the nuclear plant being in an unanalyzed condition that significantly degrades plant safety. Based on current analyses, the SSF will be declared inoperable, and action statements entered on Units 1 or 2 if power is reduced below 85% power and on Unit 3 if power is reduced below 70% power, or for any unit operating with less than 4 EFPDs since its most recent shutdown.

"Initial Safety Significance: Until confirmed by analysis or evaluation, the lack of decay heat may result in an initial over cooling of the RCS and potentially fail the various acceptance criteria of the events required to be augmented by the SSF. Consequently, the SSF will be declared inoperable for the conditions stated above. Unit 3 is being shut down for a routine refueling outage. Units 1 and 2 continue to operate at 100% power with no problems.

"Corrective Action(s): Additional evaluations are being completed to establish whether the existing analyses are applicable to the conditions outside of which they were performed and, if not, there is a reasonable assurance that successful mitigation can be accomplished with the existing procedure. If not, further licensing action may be required. These evaluations were initiated on April 4, 2012, and are ongoing."

The licensee has notified the NRC Resident Inspector. Notified the R2DO (Kathleen O'Donohue).