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| Entered date | Event description | |
|---|---|---|
| ENS 52778 | 31 May 2017 07:50:00 | This 60-day optional telephone notification is being made in lieu of an LER submittal, as allowed by 10 CFR 50.73(a)(1). This notification is made pursuant to the reporting requirements specified in 10 CFR 50.73(a)(2)(iv)(A) for an invalid actuation of one of the systems listed in 10 CFR 50.73(a)(2)(iv)(B). On April 6, 2017, at 1212 Eastern Daylight Time (EDT), an invalid actuation of emergency diesel generators (EDGs) 1, 2. 3. and 4 occurred. In support of maintenance associated with the onsite electrical distribution system, activities were in progress to power the 2C balance-of-plant (BOP) bus from the startup auxiliary transformer (SAT) followed by de-energization of the 2D BOP bus. However, flexible links between the SAT and the 2D BOP bus had not been installed. As a result, under voltage sensing relay (27SX) was not energized and an invalid SAT secondary side under voltage EDG auto start signal was generated. There was no actual under voltage on the SAT, no loss of power, and all emergency buses continued to be powered by the unit auxiliary transformer (UAT). The EDGs responded properly to the auto-start signal. The actuation was complete, in that the EDGs successfully started and ran unloaded. The EDGs were returned to standby status by 1415 EDT. Since no actual under voltage condition existed which required the EDGs to start, and the start was not in response to actual plant conditions satisfying the requirements for initiation, this event has been determined to be an invalid actuation. This event did not result in any adverse impact to the health and safety of the public. The licensee notified the NRC Resident Inspector. |
| ENS 51739 | 17 February 2016 10:36:00 | This 60-day optional telephone notification is being made in lieu of an LER submittal, as allowed by 10 CFR 50.73(a)(1). This notification is made pursuant to the reporting requirements specified in 10 CFR 50.73(a)(2)(iv)(A) for an invalid actuation of one of the systems listed in 10 CFR 50.73(a)(2)(iv)(B). On January 9, 2016, at 0946 Eastern Standard Time (EST), an invalid actuation of EDG 2 occurred. During the performance of procedure 0PT-12.2.1B, 'ECCS D/G #2 Logic Test,' procedure steps were performed out of sequence. As a result, the EDG 2 control logic was not properly defeated to prevent the auto-start prior to testing portions of the Emergency Core Cooling System (ECCS) EDG 2 logic. EDG 2 responded properly to the auto-start signal. The actuation was complete, in that the EDG started and ran unloaded. EDG 2 was returned to standby status at 1130 EST. Since no actual bus under voltage condition existed which required the EDG to start, and the start was not in response to actual plant conditions satisfying the requirements for initiation, this event has been classified as an invalid actuation. This event did not result in any adverse impact to the health and safety of the public. The licensee has notified the NRC Resident Inspector. |
| ENS 51505 | 28 October 2015 13:26:00 | This 60-day telephone notification is being made per the reporting requirements specified by 10 CFR 50.73(a)(2)(iv)(A) and 10 CFR 50.73(a)(1) to describe invalid actuation containment isolation signals affecting containment isolation valves in more than one system. On September 9, 2015 at 2103 hours Eastern Daylight Time (EDT), Unit 1 experienced a loss of electrical power to motor control center 1CB when the substation E6 feeder breaker tripped. The loss of power resulted in closure of primary containment isolation valves (PCIVs) in Unit 1 Primary Containment Isolation System (PCIS) Group 2 (i.e. Drywell Equipment and Floor Drains, Residual Heat Removal (RHR) Discharge to Radwaste, RHR Process Sample, and Traversing lncore Probe), Group 3 (i.e., Reactor Water Cleanup), and Group 6 (i.e., Containment Atmosphere Control/Dilution, Containment Atmosphere Monitoring, and Post Accident Sampling Systems). It has been determined that affected PCIVs appropriately closed. However, the limit switch within the motor operator of the inboard RWCU PCIV (i.e. 1-G31-F001) malfunctioned; resulting in an inaccurate remote position indication. Testing has confirmed that 1-G31-F001 properly closed and can perform its intended safety function. These PCIV isolations were the result of a substation E6 feeder breaker trip to motor control center 1CB and not in response to actual plant conditions (i.e., to mitigate the consequences of an event) and, therefore, were invalid. This event did not result in any adverse impact to the health and safety of the public. The NRC Resident Inspector was notified. |
| ENS 51095 | 28 May 2015 13:18:00 | This is a non-emergency notification, required by 10 CFR 21.21(d)(3)(i). Brunswick has determined that Allen Bradley relays, base model 700RTC, contain an unevaluated Complex Programmable Logic Device (CPLD). This was an unpublished design change that was implemented to replace an obsolete integrated circuit chip. The undocumented design change did not result in a part number change from Allen Bradley. There was no change to the external appearance of the relay that would indicate that a design change had been made to the relay configuration. Therefore, qualification/dedication of the modified relays have not included additional testing for the new CPLD component. Testing, performed by Duke Energy, has demonstrated that this CPLD can be affected by electrical noise from operation of nearby relays which can reset the timing of the relay. This condition was discovered as a result of a post-maintenance test of an emergency diesel generator. Additional details associated with the discovery of this condition are contained in Brunswick Licensee Event Report 1-2015-002, dated May 20, 2015. Brunswick purchased, as commercial grade, 25 of the modified Allen Bradley 700RTC relays beginning in October, 2008. Duke Energy dedicated these relays for use in safety related applications at Brunswick. The dedicated relays were not provided to any third party customers. The NRC Senior Resident Inspector has been notified. Brunswick has taken applicable compensatory measures to insure no equipment is inoperable because of these relays. This problem was previously reported by AZZ/NLI Nuclear Logistics, Inc. in EN #51030. |
| ENS 49168 | 2 July 2013 10:10:00 | This 60-day telephone notification is provided in accordance with 10 CFR 50.73(a)(1) to report an invalid actuation of the Emergency Diesel Generators (EDGs) reportable under 10 CFR 50.73(a)(2)(iv)(A). Due to the shared configuration of the onsite AC Electrical Distribution System, this event is applicable to both Units 1 and 2. On May 7, 2013, at approximately 2114 hours Eastern Daylight Time (EDT), while Operations personnel were making preparations for Unit 2 main turbine generator synchronization to the grid, a Main Generator Reverse Power Trip occurred. Main Generator Reverse Power Trip was actuated after adjusting the Manual Voltage Regulator on the Main Generator. The reverse power relay operates the Generator Primary Lockout which initiates a turbine trip and start of all four EDGs. These features functioned as designed. The main generator breaker was open at the time of the event; as such, electrical power was not lost to the emergency busses. All four EDGs started and operated as expected. Because electrical power was never lost to the emergency busses and none of the EDGs loaded to their respective emergency busses, the actuations were considered to be partial. The EDGs were returned to their standby line-up by 2229 hours on May 7, 2013. Since no actual bus under voltage condition existed which required the EDGs to start and the start was not in response to actual plant conditions satisfying the requirements for initiation, this event has been classified as an invalid actuation. This event did not result in any adverse impact to the health and safety of the public. The licensee has notified the NRC Resident Inspector. |
| ENS 48972 | 26 April 2013 12:21:00 | This 60-day telephone notification is provided in accordance with 10 CFR 50.73(a)(1) to report an invalid actuation of the Emergency Diesel Generators (EDGs) reportable under 10 CFR 50.73(a)(2)(iv)(A). Due to the shared configuration of the onsite AC Electrical Distribution System, this event is applicable to both Units 1 and 2. On March 4, 2013, at approximately 0804 EST, while performing a planned maintenance activity associated with the Unit 2 Start-Up Auxiliary Transformer (SAT), the SAT lock-out relay was inadvertently energized. This occurred when a Transmission Maintenance electrician closed the fault pressure device oil isolation valve without having previously opened the fault pressure cutoff switch. This action resulted in energizing the SAT lock-out relay and, per design, started all four EDGs. All four EDGs started and operated as expected. Because electrical power was never lost to the emergency busses and none of the EDGs loaded to their respective emergency busses, the actuations were considered to be partial. The EDGs were returned to their standby line-up by 1023 (EST) hours on March 4, 2013. Since no actual bus under voltage condition existed which required the EDGs to start and the start was not in response to actual plant conditions satisfying the requirements for initiation, this event has been classified as an invalid actuation. This event did not result in any adverse impact to the health and safety of the public. The licensee has notified the NRC Resident Inspector. |
| ENS 43791 | 19 November 2007 10:38:00 | This telephone notification is being made in accordance with 10CFR50.73(a)(1) to report an invalid actuation of the Emergency Diesel Generators (EDGs) reportable under 10CFR50.73(a)(2)(iv)(A). On September 21, 2007, at approximately 1310 EDT, while Operators were in the process of synchronizing the main turbine generator, a Generator Field Overexcitation trip occurred due to a failed transistor on the manual voltage regulator circuit board. This resulted in a primary and backup generator lockout and turbine trip. All four EDG's started and operated as expected. Because electrical power was never lost to the emergency buses and none of the EDGs loaded onto their respective emergency buses, the actuations were considered to be partial. The EDGs were returned to their standby line-up by 1615 on September 21, 2007. Since no actual bus undervoltage condition existed which required the EDG's to start and the start occurred inadvertently as a result of a single component failure, this event has been classified as an invalid actuation. This invalid EDG start event was entered into the corrective action program (i.e., NCR 247573) Initial Safety Significance Evaluation - The safety significance is considered to be minimal. The EDGs started and operated normally. Offsite electrical power to the Emergency buses was never lost. Corrective Actions - The main turbine generator manual voltage regulator circuit board was replaced. The licensee notified the NRC Resident Inspector. |