Semantic search
| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 53500 | 11 July 2018 05:00:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Meteorological Data Unavailable | On July 11, 2018, as part of pre-planned maintenance, the site meteorological tower will be removed from service. The tower will be out of service for approximately 11 days. As a result, this is reportable under 10CFR 50.72 (b)(3)(xiii). During the time the data is not available from the meteorological tower; compensatory measures will be in place to obtain the data from the National Weather Service if necessary. The (NRC) Resident Inspector has been notified. | ||
| ENS 50743 | 19 January 2015 03:31:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Normal Technical Support Center Power | At 2131 CST on January 18, the Duane Arnold Energy Center (DAEC) Technical Support Center (TSC) Normal Power was lost when a single phase to the T4 '36KV-12.5KV DAEC SITE TRANSFORMER' was lost due to a blown primary side fuse. Automatic power transfer occurred to maintain power to the TSC from the TSC Emergency Diesel Generator (EDG) which automatically started. The TSC remained functional throughout the incident. This notification is being made pursuant to 10 CFR 50.72(b)(3)(xiii) due to the loss of an emergency assessment capability. An update will be provided once the normal power supply has been restored. The licensee notified the NRC Resident Inspector.
Normal power restored to the TSC. The licensee notified the NRC Resident Inspector. Notified the R3DO (Duncan). | Emergency Diesel Generator | |
| ENS 49747 | 21 January 2014 04:30:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Technical Support Center Emergency Diesel Generator Out of Service | On 1/20/14 at 2230 CST, an interruption in the control power to the TSC diesel generator was discovered. Investigation revealed a blown fuse supplying the TSC diesel generator control panel. The blown fuse has resulted in the TSC diesel generator starting batteries depleting. The fuse has since been replaced, and the TSC diesel generator starting batteries are currently recharging. The TSC diesel generator remains non-functional until the starting batteries are charged. This notification is being made in accordance with 10 CFR 50.72(b)(3)(xiii) due to the unplanned loss of the backup power supply to the Emergency Response Facility (ERF). The NRC Resident Inspector has been informed. An update notification will be made when the TSC diesel generator has been restored to fully functional status.
At 1400 CST, the licensee restored the TSC emergency diesel generator to functional status. The NRC Resident Inspector was notified by the licensee. Notified R3DO (Valos). | Emergency Diesel Generator | |
| ENS 49557 | 19 November 2013 10:20:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Technical Support Center Emergency Backup Power Supply Maintenance | A planned maintenance evolution at the Duane Arnold Energy Center (DAEC) will remove the emergency power supply to the TSC from service. The TSC would be rendered non-functional with the loss of normal power. The repair to the power supply is expected to last 1 day. If an emergency is declared requiring TSC activation during this period, the TSC will be staffed and activated using existing emergency planning procedures. Maintenance will be expedited to restore the emergency power supply to service. This notification is being made in accordance with 10 CFR 50.72(b)(3)(xiii) due to the loss of an Emergency Response Facility (ERF). An update will be provided once the TSC emergency power supply has been restored to normal operation. The NRC Resident Inspector has been notified.
The emergency power has been returned to service to the TSC. The licensee has notified the NRC Resident Inspector. Notified R3DO (Hills). | ||
| ENS 49415 | 7 October 2013 15:27:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Planned Maintenance Causing Loss of Meteorological Tower Data | A planned maintenance evolution at the Duane Arnold Energy Center (DAEC) will de-energize the Meteorological Data Tower. No other indications or annunciators will be unavailable during this maintenance to affect the plant's ability to assess or monitor an accident or transient in progress. National Weather Service data is expected to be available throughout the duration of the planned maintenance. A follow up notification will be provided when power to the Meteorological Data Tower has been restored. The NRC Resident Inspector has been notified.
Maintenance activities on the Meteorological Data Tower is complete and the tower has been returned to service. The licensee has notified the NRC Resident Inspector. R3DO (Skokowski) notified. | ||
| ENS 49383 | 25 September 2013 08:04:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Normal Tsc Power Due to Transformer Isolation | At 0304 (CDT), on Sept 25, 2013, the Duane Arnold Energy Center (DAEC) Technical Support Center (TSC) normal power supply was lost when the T4 '36KV-12.5KV DAEC SITE TRANSFORMER' was lost. Automatic power transfer occurred to maintain power to the TSC from the TSC Emergency Diesel Generator (EDG) which automatically started. Prior to the loss of normal power, the TSC Emergency Diesel Generator maintenance functional testing had been completed and was in standby readiness, awaiting post maintenance testing to be completed on the auto start circuit. The TSC Emergency Diesel Generator responded normally to the loss of power and energized TSC loads. The TSC remained functional throughout the incident. This notification is being made pursuant to 10 CFR 50.72(b)(3)(xiii) due to the loss of an emergency assessment capability. An update will be provided once the normal power supply has been restored. The NRC Resident Inspector has been notified.
The TSC normal power supply was returned to service at 1830 EDT on 11/2/13. The licensee will be notifying the NRC Resident Inspector. Notified R3DO (Daley). | Emergency Diesel Generator | |
| ENS 49357 | 19 September 2013 09:50:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Technical Support Center Emergency Diesel Generator Removed from Service for Planned Maintenance | A planned maintenance evolution at the Duane Arnold Energy Center (DAEC) will remove the emergency power supply to the TSC from service. The TSC would be rendered non-functional with the loss of emergency power. The repair to the power supply is expected to last 2 hours. If an emergency is declared requiring TSC activation during this period, the TSC will be staffed and activated using existing emergency planning procedures. Maintenance will be expedited to restore the emergency power supply to service. This notification is being made in accordance with 10CFR50.72(b)(3)(xiii) due to the loss of an Emergency Response Facility (ERF). An update will be provided once the TSC emergency power supply has been restored to normal operation. NRC Resident Inspector has been notified.
The TSC EDG remains unavailable due to emergent work. The licensee has notified the NRC Resident Inspector. Notified R3DO (Riemer).
The TSC EDG has returned to functional status. The licensee notified the NRC Resident Inspector. Notified R3DO (Dickson). | Emergency Diesel Generator | |
| ENS 49092 | 6 June 2013 13:00:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Technical Support Center Emergency Power Supply Removed from Service for Planned Maintenance | A planned maintenance evolution at the Duane Arnold Energy Center (DAEC) has removed the emergency power supply to the TSC from service as of 0900 EDT. If a loss of the normal power supply to the TSC were to occur during this period, the TSC would be rendered non-functional. The repair to the power supply is expected to last 6 hours. If an emergency is declared requiring TSC activation during this period, the TSC will be staffed and activated using existing emergency planning procedures. Maintenance will be expedited to restore the emergency power supply to service. This notification is being made in accordance with 10 CFR 50.72(b)(3)(xiii) due to the loss of an Emergency Response Facility (ERF). An update will be provided once the TSC emergency power supply has been restored to normal operation. The licensee has notified the NRC Resident Inspector.
The TSC diesel generator has been returned to functional status. The NRC Resident Inspector has been notified R3DO (Lipa) has been notified. | ||
| ENS 48648 | 3 January 2013 15:30:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Erds Capability | At 0930 (CST) on January 03, 2013 NextEra Energy Duane Arnold discovered that the Emergency Response Data System (ERDS) was no longer capable of transmitting plant data to the NRC. The loss of ERDS is reportable per 50.72(b)(3)(xiii). At 1151 (CST) on January 03, 2013 Information Management personnel restored ERDS to working status. The NRC Resident (Inspector) has been notified. The licensee has the cause under investigation.
At 1725 (CST) on January 03, 2013 NextEra Energy Duane Arnold experienced a four minute interruption of the Emergency Response Data System (ERDS). During this time, ERDS was not capable of transmitting plant data to the NRC. The loss of ERDS is reportable per 10 CFR 50.72(b)(3)(xiii). The interruption of ERDS is related to a previous problem with the system reported under EN #48648. Troubleshooting of ERDS continues to ensure long-term reliability. Additional interruptions of ERDS are possible during this troubleshooting, and a follow-up notification will be made when ERDS reliability is assured. The licensee informed the NRC Resident Inspector. Notified R3DO (Skokowski), ERDS Group and CAT Group via email.
Maintenance is complete on the ERDS system. It was tested satisfactorily on 01/15/13 at 1130 CST and returned to fully functional status. The NRC Resident Inspector has been informed. Notified R3DO (Stone), ERDS Group and CAT Group via email. | Emergency Response Data System | |
| ENS 48510 | 16 November 2012 14:10:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Spds Out of Service Due to Planned Maintenance | A planned maintenance evolution at Duane Arnold Energy Center (DAEC) to replace a hard drive in the plant process computer will result in a loss of all SPDS indication for a duration of less than six hours. There is no planned maintenance affecting Primary Indications or Annunciators in the Control Room which would affect the plant's ability to assess or monitor an accident or transient in progress. This notification is being made pursuant to 10CFR50.72(b)(3)(xiii). The licensee will notify the NRC Resident Inspector.
The planned maintenance has been completed and SPDS returned to service at 1431 EST. The licensee has notified the NRC Resident Inspector. R3DO(Kunowski) notified. | ||
| ENS 48296 | 11 September 2012 08:08:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Technical Support Center Non-Functional Due to Planned Maintenance | A planned maintenance evolution at the Duane Arnold Energy Center (DAEC) will remove the TSC (Technical Support Center) ventilation system from service. The TSC would be rendered non-functional with the loss of ventilation. The repair to the TSC ventilation is expected to last 3 days. If an emergency is declared requiring TSC activation during this period, the TSC will be staffed and activated using existing emergency planning procedures. Maintenance will be expedited to restore ventilation to the TSC. This notification is being made in accordance with 10CR50.72(b)(3)(xiii) due to the loss of an Emergency Response Facility (ERF). An update will be provided once the TSC ventilation system has been restored to normal operation. The licensee notified the NRC Resident Inspector
The TSC maintenance has been completed. The TSC has been restored to service. The NRC Resident Inspector has been informed. Notified R3DO (Kunowski). | ||
| ENS 48214 | 21 August 2012 09:07:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Technical Support Center Out of Service | A planned maintenance evolution at the Duane Arnold Energy Center (DAEC) will remove the emergency power supply to the TSC from service. The TSC would be rendered non-functional with the loss of emergency power. The repair to the power supply is expected to last three days. If an emergency is declared requiring TSC activation during this period, the TSC will be staffed and activated using existing emergency planning procedures. Maintenance will be expedited to restore the emergency power supply to service. This notification is being made in accordance with 10CFR50.72(b)(3)(xiii) due to the loss of an Emergency Response Facility (ERF). An update will be provided once the TSC emergency power supply has been restored to normal operation. NRC Resident has been notified.
Maintenance has been completed on the TSC. The TSC has been returned to service. Notified R3DO (Duncan). | ||
| ENS 47557 | 29 December 2011 15:10:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Planned Maintenance on Plant Process Computer | A planned maintenance evolution at the Duane Arnold Energy Center (DAEC) to replace power supplies in the plant process computer (Link 2) will result in a loss of some SPDS indications for a duration of less than 5 hours. No other indications or annunciators will be unavailable during this maintenance to affect the plant's ability to assess or monitor an accident of transient in progress. The licensee has notified the NRC Resident Inspector.
At 1006 CST on 12/29/11 the plant process computer (Link 2) was successfully restored and SPDS is functioning properly and returned to service. The licensee has notified the NRC Resident Inspector. Notified R3DO (Duncan). | ||
| ENS 47490 | 30 November 2011 15:35:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Plant Process Computer Out of Service Due to Planned Maintenance | A planned maintenance evolution at the Duane Arnold Energy Center (DAEC) to replace power supplies in the plant process computer will result in a loss of some Safety Parameter Display System (SPDS) indications for a duration of less than 5 hours. No other indicators or annunciators will be unavailable during this maintenance to affect the plant's ability to assess or monitor an accident or transient in progress. This notification is being made pursuant to 10 CFR 50.72(b)(3)(xiii). The NRC Resident Inspector has been notified.
The licensee reports that the plant process computer work has been completed and SPDS has been functionally tested and returned to an operable status. The licensee will notify the NRC Resident Inspector. R3DO (Riemer) notified. | Safety Parameter Display System | |
| ENS 47431 | 11 November 2011 16:21:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Technical Support Center Inoperable Due to Planned Maintenance | At 1021 hrs. (CST) on November 11, 2011, the Duane Arnold Energy Center (DAEC) Technical Support Center (TSC) Ventilation Fan 1VAC070 was removed from service for pre-planned maintenance. The expected duration of the maintenance is 6 hours. The backup plan is to relocate key TSC personnel to the Control Room where the Standby Filter Units protect personnel. This notification is being made pursuant to 10 CFR 50.72(b)(3)(xiii) due to a loss of emergency response facility. The licensee has notified the NRC Resident Inspector. * * * UPDATE FROM HAN OLSON TO PETE SNYDER AT 1907 EST ON 11/11/11 * * * The TSC Ventilation Fan 1VAC070 has been returned to service and functionally tested so the TSC has been returned to service. The licensee notified the NRC Resident Inspector. Notified R3DO (Giessner). | ||
| ENS 47354 | 19 October 2011 15:00:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Technical Support Center Emergency Diesel Non-Functional | At 1000 (CDT), on October 19, 2011, the Duane Arnold Energy Center (DAEC) Technical Support Center (TSC) Emergency Diesel Generator (EDG) was declared non-functional due to its failure to maintain required voltage during routine testing. The plant is currently in the process of determining the cause of the failure. Normal power to the TSC is currently available. The licensee notified the NRC Resident Inspector.
The TSC Emergency Diesel Generator failure has been identified and corrected. The unit has been successfully tested, restoring the TSC Emergency Diesel Generator and TSC to a functional status. The licensee has notified the NRC Resident Inspector. Notified the R3DO (Hills). | Emergency Diesel Generator | |
| ENS 47350 | 18 October 2011 09:50:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Technical Support Center Emergency Diesel Generator Out of Service | At 0450 (CDT), on October 18, 2011, the Duane Arnold Energy Center (DAEC) Technical Support Center (TSC) Emergency Diesel Generator (EDG) was removed from service for preplanned maintenance. The expected duration of the maintenance is 12 hours. Normal power to the TSC will be available for the duration of the maintenance. This notification is being made pursuant to 10 CFR 50.72(b)(3)(xiii) The NRC Resident Inspector has been notified.
The Duane Arnold Energy Center (DAEC) Technical Support Center (TSC) Emergency Diesel Generator (EDG) was returned to service at 1637 CDT on 10/18/11. The licensee informed the NRC Resident Inspector. Notified R3DO (Daley). | Emergency Diesel Generator | |
| ENS 47235 | 1 September 2011 15:50:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Technical Support Center Diesel Generator Non-Functional | At 1050 (CDT), on September 1, 2011, the Duane Arnold Energy Center (DAEC) Technical Support Center (TSC) Emergency Diesel Generator (EDG) was declared non-functional due its failure to start during routine testing. The plant is currently in the process of determining the cause of the failure. Normal power to the TSC is currently available. This notification is being made pursuant to 10 CFR 50.72(b)(3)(xiii). The licensee notified the NRC Resident Inspector.
The TSC Emergency Diesel Generator failure has been identified and corrected. The unit has been successfully tested, restoring the EDG and TSC to a functional status." The TSC was restored at 1145 CDT. The licensee will notify the NRC Resident Inspector. Notified the R3DO (Kunowski). | Emergency Diesel Generator | |
| ENS 47138 | 10 August 2011 06:00:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Potential Loss of Tsc Operability While Performing Planned Maintenance | A planned maintenance evolution at the Duane Arnold Energy Center (DAEC) will have the potential to remove the plant computer systems (Plant Process Computer, Intranet, and Internet) from service. The TSC would be rendered non-functional with the loss of all computer systems. The replacement and testing of the automatic power transfer relay is expected to de-energize the computer systems for less than 20 minutes at any time. If an emergency is declared requiring TSC activation during this period, the TSC will be staffed and activated using existing emergency planning procedures. Maintenance will be terminated and power will be restored to the plant computer systems. The restoration of power to all computer systems is estimated to take less than one hour. This notification is being made in accordance with 10CFR50.72 (b)(3)(xiii) due to the potential loss of an Emergency Response Facility (ERF). An update will be provided once the plant computer systems power supplies have been restored to normal operation. The licensee has notified the NRC Resident Inspector.
The TSC has been restored to operational status. The licensee has notified the NRC Resident Inspector. Notified R3DO (Dickson).
The licensee is performing planned maintenance on the TSC automatic power transfer relay which could render the TSC inoperable if power to the TSC computers is lost. Maintenance is expected to commence at 2130 CDT. The licensee has notified the NRC Resident Inspector. Notified R3DO (Peterson). | ||
| ENS 46542 | 14 January 2011 14:40:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Technical Support Center Out of Service Due to Maintenance | At 0840 (CST) on Friday, January 14, 2011, a portion of the Duane Arnold Energy Center (DAEC) Technical Support Center (TSC) ventilation was removed from service to conduct maintenance on the charcoal filter medium. The TSC Stand-by Filter Unit (TSC-SFU) was found with deluge water in the bottom of the charcoal filtration bed, and is therefore non-functional. Under certain accident conditions the TSC may become unavailable due to the inability of the ventilation system to maintain a habitable atmosphere. The licensee has notified the NRC Resident Inspector. This notification is being made in accordance with 10 CFR 50.72 (b) (3) (xiii) due to a loss of emergency response facility. * * * UPDATE AT 1105 ON 1/21/11 FROM ROB SPADING TO PETE SNYDER * * * Maintenance has been completed and the TSC is returned to service as of 1005 CST. Notified R3DO (Bloomer). | ||
| ENS 45340 | 11 September 2009 16:01:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Technical Support Center Unavailable Due to Maintenance | At 1100 on Friday, September 11, 2009 a portion of the Duane Arnold Energy Center power plant (DAEC) Technical Support Center (TSC) ventilation system, Technical Support Center (TSC) air conditioning system, and Technical Support Center (TSC) computer system was removed from service for maintenance on Technical Support Center (TSC) electrical power supply. The electrical power supply being removed supports air conditioning, filtration system and computers. Under certain accident conditions the TSC may become unavailable due to the inability of the ventilation system to maintain a habitable atmosphere and loss of computer systems. Compensatory measures exist to rapidly restore power to the TSC if necessary based upon TSC activation requirements. The TSC power supply maintenance is scheduled to complete at 1800 on Friday, September 11, 2009. The licensee has notified the NRC Senior Resident Inspector. This notification is being made in accordance with 10 CFR 50.72 (b) (3) (xiii) due to loss of an emergency response facility.
The TSC power supply maintenance has been completed and the Technical Support Center(TSC) is now fully available. The licensee will notify the NRC Resident Inspector. Notified the R3DO(Ring). | ||
| ENS 44291 | 12 June 2008 16:30:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Unusual Event Declared Due to a Major Loss of Response and Communications Capability | At 1130CDT on 6/12/2008, the Duane Arnold Energy Center was informed due to flooding in the local area that access to the Joint Information Center (JIC), the Offsite Radiological Analytical Laboratory (ORAL), the Offsite Relocation and Reassembly Area (ORRA), and the Emergency Operations Facility (EOF) have been lost. This constitutes a reportable condition per 10CFR50.72(b)(3)(xiii) due to the major loss of offsite response capability. The ORAL function will be maintained by the Iowa State Hygienics Lab. At the present time the remaining facilities are being relocated or moved to the Linn County Emergency Operations Center (EOC) located at the Kirkwood Community College Campus. Also, although multiple roads in the area are closed due to high water level, evacuation capability in the EPZ is being maintained. Also, at 1256CDT on 6/12/2008, Duane Arnold Energy Center was informed that local commercial phone service through the Palo phone system has been lost. This service also includes our ability to fax and access the internet. We have also lost our FTS2001 ENS connection. Again, per 10CFR50.72(b)(3)(xiii) this represents a major loss of offsite communication capability. Offsite communications is being maintained currently thorough our microwave and cell phone systems. Onsite communications are possible through our in house PBX and page system. Contingency plans are in effect to setup a mobile satellite uplink that would include voice and data capability. The NRC Resident Inspector has been informed.
At 1430CDT on 6/12/2008, Duane Arnold Energy Center lost communications capability via commercial phone line, FT2001 ENS system and the microwave phone system. This meets the threshold criteria of an EAL classification of an Unusual Event. At 1440CDT the Shift Manager declared that Unusual Event and notifications were made to Linn County Emergency Management Agency, Benton County Emergency Management Agency and the Iowa Homeland Security Emergency Management Division. Currently, offsite communication is still possible via our installed cell phone and satellite systems and onsite communications remain possible via our PBX and page system. The NRC Resident Inspector has been informed. Notified ET Member (B. Mallet), all IRD Management (B. McDermott, W. Gott, M. Leach), Commissioners' Staffs (D. Skeen, T. Hipschman, S. Baggett, J. Thoma, D. Coe), EDO Staff (J. Adams), PAO (E. Brenner), OCA (D. Decker), RDOs (R. Summers, B. Bonser, P. Louden, G. Miller), FEMA, DOE, USDA, and HHS.
On 6/12/2008 at 1444 FPLE-DAEC declared an unusual event (SU6.2) due to loss of all offsite communication. These systems included the FTS 2001, microwave phone lines, and commercial phone lines due to flooding of the Palo, Iowa phone station. Since that date FPLE-DAEC has reestablished two of the three offsite communication methods. The microwave telephone system has been restored and the commercial phone lines have been restored through a new exchange through the town of Shellsburg, Iowa, which was not affected by the flood. With these two lines of offsite communications reestablished the DAEC will de-escalate from the Unusual event from the loss of offsite communication. FPLE-Duane Arnold will be issuing a press release stating the unusual event has been cancelled. The NRC senior resident inspector has been notified and the state of Iowa, Linn County, and Benton county will be notified. The licensee exited the Unusual Event at 1428 EDT on 06/19/08. Notified R3DO (Kunowski), NRR EO (Fred Brown), IRD MOC (Bill Gott), DHS, and FEMA.
Multiple power sources are now available to the Emergency Operations Facility. The licensee notified the NRC Resident Inspector. Notified the R3DO (Kozak). | ||
| ENS 42299 | 2 February 2006 00:55:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Site External Communications | At approximately 18:55 CST, the site lost external communications. At 1937 CST, Duane Arnold declared an Unusual Event due to loss of communications to most offsite agencies. Communications with the county were operating via microwave however, other external communications were not working. The site believed that the loss was due to a "single microwave tower malfunction." The county was contacted directly and other offsite communications (including this event) were being made using a cell phone. The Headquarters Operation Officer was able to contact the Control Room using a commercial phone number. The plant is currently in day 2 of a 14 day RCIC LCO. At 22:35 EST, the site verified that they now have intermittent communications using commercial phone lines. The licensee will not exit the Unusual Event until they have restored communications and know the reason for losing communications. The NRC Resident Inspector is at the site.
Duane Arnold terminated the Unusual Event at 01:00 CST. The licensee restored site communications by correcting the microwave tower malfunction. The ENS line became operable at 03:32 EST. The licensee notified the NRC Resident Inspector. Notified R3DO (Riemer), NRR EO (Martin), IRD MOC (Leach), FEMA (Dunker), DHS (Christenson). | ||
| ENS 42241 | 4 January 2006 17:00:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Partial Loss of Emergency Sirens | On 01/04/06, while performing the Emergency Siren Monthly Test it was determined that 14 out of 143 (9.7%) of the Emergency sirens had failed. A Notification is required because of the major loss of offsite response capability, i.e., the public prompt notification system. Calculating the percentage of failures with a total count of 143 sirens results in an approximately 10% failure rate or a 'significant number of failures.' This information was immediately discussed with Licensing and determined that a conservative decision is to make an 10 CFR 50.72(b)(3)(xiii) reportability notification. The State of Iowa, FEMA, and Benton and Linn Counties have also been notified. Electricians were immediately dispatched to begin to troubleshoot and repair the 14 declared INOP sirens. Compensatory actions have been taken. The licensee notified the NRC Resident Inspector. | ||
| ENS 40995 | 28 August 2004 06:46:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Failure of the Plant Process Computer Due to Loss of Power Supply | At approximately 01:46 (CDT) on August 28, 2004, the Duane Arnold Energy Center plant process computer (PPC) failed due to a lost power supply. This computer system provides the control room with its Safety Parameter Display System (SPDS), the Emergency Response Data System (ERDS) and MIDAS. With the loss of the PPC, and specifically the subsequent loss of SPDS, ERDS, and MIDAS representing a major loss of emergency assessment capability, the reportability criteria of 10CFR50.72(b)(3)(xiii) was met. No other control room indications, or communication systems were affected by this computer outage. They expect to have a new power supply at the site by noon today and installed within two hours after arrival. The NRC Resident Inspector will be notified.
The Duane Arnold Energy Center plant process computer (PPC) power supply has been replaced and operation of the PPC has been restored. The licensee has notified the NRC Resident Inspector. | Emergency Response Data System Safety Parameter Display System |