Event Notification Report for April 05, 2006

HIGH PRESSURE COOLANT INJECTION DECLARED INOPERABLE (HPCI)

"During performance of a Unit 3 High Pressure Coolant Injection System (HPCI) Logic System Functional Test, the High Pressure Coolant Injection (HPCI) system was found to be inoperable. The inoperability is due to a logic failure that would prevent the automatic opening of MO-3-23-015, 'HPCI TURBINE STEAM LINE INBOARD ISOLATION VAVLE'. MO-3-23-015 is a normally open valve located inside Primary Containment. The HPCI system initiates upon receipt of a reactor low water level (level 3) signal or a high drywell pressure signal. Upon a HPCI system initiation MO-3-23-015 is required to automatically open, if closed, with no isolation signal present. The automatic opening of MO-3-23-015 is required to ensure the design function of HPCI is fulfilled. The design function of HPCI is to assure that the reactor is adequately cooled to limit fuel-clad temperature in the event of a small break in the nuclear system and loss of coolant, which does not result in rapid depressurization of the reactor vessel. HPCI permits the nuclear plant to be shut down while maintaining sufficient reactor vessel water inventory until the reactor vessel is depressurized.

"The HPCI system inoperability has no immediate impact on plant operations. The inoperability places Unit 3 in a 14-day shutdown Tech Spec Action Statement. The 14-day shutdown Tech Spec Action Statement commenced on 04/05/06 @ 0824 when the Logic System Function Test was started.

"A troubleshooting and repair team has been initiated to determine a cause and repair of the deficiency."

The licensee notified the NRC Resident Inspector.

* * * RETRACTION AT 09:10 ON 5/11/2006 FROM DAVE FOSS TO ABRAMOVITZ * * *

"The purpose of this notification is to retract a previous report made on 4/5/06 at 1643 hours (EN# 42478). On 4/5/06, the High Pressure Coolant Injection (HPCI) system was removed from service and declared inoperable for the performance of a Logic System Functional Test (LSFT). During the LSFT, a condition was discovered in the open control logic circuit of the MO-3-23-015 (HPCI Turbine Steam Line Inboard Isolation Valve) that would have inhibited automatic opening of the valve on a HPCI initiation signal. Notification of this issue to the NRC on 4/5/06 was initially made as a result of the belief that the MO-3-23-015 may not have been capable of being opened for design events. It was subsequently determined that a relay contact exhibited high resistance during the LSFT. The relay was replaced on 4/6/06 (IR 475307).

"Since the initial report, Engineering has performed an operability review that evaluated the impact that the relay contact high resistance condition had on the ability of the HPCI system to perform its safety function. It was determined that the relay contact degradation did not cause the HPCI system to be inoperable. The MO-3-23-015 is a normally open Primary Containment Isolation Valve. MO-3-23-015 would only isolate for conditions where HPCI would be rendered inoperable. Automatically re-opening the MO-3-23-015 valve is not a safety related function. Therefore, HPCI was capable of performing its safety function with the degraded relay contact."

Notified the R1DO (Dimitriadis). The licensee notified the NRC Resident Inspector.

ABNORMAL OPERATING PROCEDURE (AOP) FOR STATION BLACKOUT COULD NOT BE PERFORMED IN SPECIFIED TIME PERIOD


"DAEC (Duane Arnold Energy Center) abnormal operating procedure AOP 301.1 for Station Blackout specifies that 30 minutes are allowed to establish alternate ventilation for RCIC (Reactor Core Isolation Cooling) /HPCI (High Pressure Coolant Injection) rooms, switchgear rooms, battery rooms, and the Main control room. During validation demonstration conducted on April 5, 2006 for the NRC Components team (from NRC Region 3 Office) the 30 minutes requirement was not met with the control room alternate ventilation taking about 60 minutes and with the other areas also exceeding their time requirements. This event is reportable as an unanalyzed condition that significantly degraded plant safety pursuant to 10 CFR 50.72(b)(3)(ii) reportability notification."

The NRC Resident Inspector was notified of this event by the licensee.

* * * RETRACTION FROM MURRELL TO HUFFMAN AT 1442 EDT ON 6/01/06 * * *

"Duane Arnold Energy Center is retracting event number 42479 which was reported to the NRC Operations Center on 4/5/06 at 1855. This event is now determined to be not reportable because further evaluation to assess the significance of the delays in establishing alternate control room ventilation determined that the delay did not result in an adverse temperature increase in the affected areas. Specifically, the control room and back panel area temperature rise was evaluated using a detailed mass and heat transfer model of the affected areas. The evaluation confirmed that delays in establishing alternate control room ventilation did not adversely impact station commitments to 10 CFR 50.63 or accident responses outlined in UFSAR Section 15.3.2. Other areas required to have alternate ventilation established within 30 minutes had previously been successfully validated. Therefore, this event is not reportable as an unanalyzed condition that significantly degraded plant safety. The analyses and the bases for this retraction can be found under the plant corrective action program."

The licensee notified the NRC Resident Inspector. R3DO (Kozak) notified.

REACTOR SCRAM FOLLOWING MAIN TURBINE CONTROL VALVE FAST CLOSURE

"Two I & C technicians were performing a 24 month calibration on 2S32R017, Megavar & Voltmeter Recorder in accordance with 57CP-CAL-010-2, Esterline Angus Megavar & KV Recorder. This activity was being performed on Work Order 2042825001. At the approximate time the recorder was being removed from service the shift received a RPS trip from a MTCV [Main Turbine Control Valve] Fast Closure. The control valve fast closure scram was caused by a power load imbalance. Both RFP's [Reactor Feed Pumps] tripped on high reactor water level and RCIC and HPCI were used (for 7 and 2 minutes respectively) to control RWL [Reactor Water Level]. Eight SRV's [Safety Relief Valves] opened momentarily on high reactor pressure. The highest reactor pressure indicated was 1120 psig and the lowest RWL indicated was +7 inches. A main condenser vacuum transient due to loss of seals required use of HPCI and RCIC."

The licensee characterized the scram as uncomplicated. All systems functioned as required and nothing unusual or not understood besides what caused the initial power load unbalance signal and resulting MTCV fast closure. All rods fully inserted. The unit is currently at normal pressure and water level for Mode 3. MSIVs remained opened and decay heat is being discharged to the main condenser. The scram had no impact on Unit 1. Offsite on onsite electrical conditions remained normal. The licensee was not in any significant LCO at the time of the event.

The licensee notified the NRC Resident Inspector.

FITNESS FOR DUTY - CONFIRMED POSITIVE FOR NON-LICENSED CONTRACTOR SUPERVISOR

A non-licensed contract supervisor had a confirmed positive for alcohol while attempting to gain access the plant this morning. The contractor's access to the plant has been suspended. A review of previous work is being performed. Contact the Headquarters Operations Officer for additional details.

The NRC Resident Inspector has been notified.

BOTH TRAINS OF HIGH PRESSURE INJECTION (HPI) DECLARED INOPERABLE DUE TO POTENTIAL AIR BINDING OF PUMPS

"TMI declared both High Pressure Injection Trains not operable due to air void in the suction line from the Sodium Hydroxide tank. The postulated issued is that in the event of a small break LOCA where the plant would need to go on HPI piggy back Ops (the Low Pressure Injection supplying suction to the High Pressure Injection pumps) the air could cause the HPI pumps to become air bound.

"The Plant entered a shutdown Tech Spec 3.0.1 at 0804 [EDT] and exited the timeclock at 0850 [EDT] when the Sodium Hydroxide tank was isolated, thus isolating the air void from the ECCS (Emergency Core Cooling System) pumps."

The licensee is continuing their investigation into root cause and operability.

The licensee will inform the NRC Resident Inspector.

* * * RETRACTION FROM A. MILLER TO P. SNYDER AT 1301 EDT ON 6/2/06 * * *

"The purpose of this call is to retract the notification (Event Number 42475) made by TMI Unit 1, Docket No. 50-289 / License No. DPR-50. On April 5, 2006, at 1408 hours, the Shift Manager made a notification (Event Number 42475) to the NRC Operations Center in accordance with 10 CFR 50.72 (b)(3)(v)(D) (i.e. any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident). The event was reported as 'Both trains of High Pressure Injection (HPI) Declared Inoperable due to potential air binding of Pumps.'

"On April 5, 2006, air voids were found in the NaOH tank piping, upstream of the HPI pumps, and the Shift Manager conservatively declared both trains of HPI inoperable due to the air voids. This placed TMI-1 in a 1-hour shutdown Limiting Condition for Operation (LCO). The isolation valves for the NaOH tank line piping were then Closed to eliminate the possibility that the voids could be transported to the HPI pumps. The HPI pumps were then declared operable and TMI-1 entered a 72-hour shutdown LCO. During the 72-hour LCO, the air bubble was vented from the system. An initial extent of condition evaluation was completed and an event response team was established.

"Numerical Applications, Inc. (NAI) was retained to perform GOTHIC Model run on the two phase flow conditions and determine the percent air density of the water at the suction to the Low Pressure Injection (LPI) pumps and the HPI pumps. The NAI analysis concluded that the densities of air found at the suction of the LPI and HPI pumps were below the safe operating level as stated by the pump manufacturers. Based on the results of the evaluation, TMI-1 has determined that the LPI and HPI pumps were operable. Past operability of these pumps with the maximum size air bubble found is affirmed. Therefore, this event does not meet the 10 CFR 50.72 or 10 CFR 50.73 reporting criteria and the notification for Event Number 42475 is retracted. The resident inspector has been notified."

Notified R1DO (T. Jackson).

OFFSITE NOTIFICATION TO STATE AND LOCAL OFFICIALS CONCERNING TRITIUM DETECTION IN DRAIN SYSTEM

"This notification is being made in accordance with 10CFR50.72(b)(2)(xi), i.e., notification of a government agency. FENOC provided a courtesy notification to state and local officials based on the detection of very low levels of tritium in the plant underdrain system.

"During routine quarterly sampling of the Perry plant's underdrain system on March 28, 2006, very low levels of tritium were detected in an underdrain system manhole. The plant's underdrain system directs water under the plant to the Emergency Service Water Pumphouse, where it is monitored and discharged.

"Samples taken off-site show no indications of detectable tritium. No reportable limits have been exceeded."

The NRC Resident Inspector has been notified.