Semantic search
| Entered date | Event description | |
|---|---|---|
| ENS 53374 | 1 May 2018 20:42:00 | At 1551 hrs (CDT) on 5/1/2018, with the plant in Mode 5, a division one Reactor Pressure Vessel (RPV) Level 1 signal was received; however there was no actual change in RPV level. RPV Level remained at High Water Level supporting refuel operations. This caused an actuation of division one Load Shed and Sequencing system that shed and then re-energized the 15 bus. Division one diesel generator started from standby. Residual Heat Removal pump 'A', which was in shutdown cooling mode, was lost during the bus shed, and was re-sequenced upon re-energization of the 15 bus. Upon restoration of shutdown cooling, the RHR pump discharged into the RPV. RCS temperature increased approximately 5 degrees Fahrenheit as a result of the loss of shutdown cooling. The cause of the actuation signal is under investigation. In accordance with NUREG 1022, Event Reporting Guidelines, this event is conservatively reported under 10 CFR 50.72(b)(2)(iv)(A) as an event that results in emergency core cooling system discharge into the RCS as a result of a valid signal, under 10 CFR 50.72(b)(3)(iv)(B)(8) as an event that results in the actuation of emergency ac electrical power systems, and under 10 CFR 50.72(b)(3)(v)(B) as an event or condition that at the time of discovery could have prevented the fulfillment of a safety function (remove residual heat). The licensee notified the NRC Resident Inspector. |
| ENS 53335 | 13 April 2018 21:04:00 | At 1208 CDT on April 13, 2018, GGNS (Grand Gulf Nuclear Station) identified cracks in the primary containment concrete penetration (outer wall) around feed water line 'B'. There are no available dimensions for crack width or depth until further inspections are performed. In accordance with NUREG 1022, Event Reporting Guidelines 10 CFR 50.72 and 10 CFR 50.73, Section 3.2.4, any event or condition that results in the condition of the nuclear power plant, including its principal safety barriers being seriously degraded, requires that when a principal safety barrier is declared inoperable the condition must be reported under 10 CFR 50.72 (b)(3)(ii). The licensee has notified the NRC Resident Inspector.
Grand Gulf Nuclear Station (GGNS) personnel performed an inspection of the wall around feed water line 'B'. This inspection included the protective coating in the identified area and a partial inspection of the underlying concrete. The inspection of the protective coating found a collection of non-linear anomalies, chipping, and flaking. The inspection found non-significant linear indications in the concrete. Grand Gulf Nuclear Station determined that the collection of non-significant coating imperfections and non-significant indications in the concrete do not constitute serious degradation of primary containment. The indications do not adversely impact the operability, mission time, or safety-function (as described per Technical Specification 3.6.1.1, Primary Containment) of the containment structure. The as-found conditions have been entered into the GGNS corrective action program for final disposition. The containment structure is operable, therefore, GGNS is retracting this event notification. The licensee has notified the NRC Resident Inspector. Notified R4DO (Kellar). |
| ENS 53201 | 10 February 2018 22:37:00 | On 2/10/18 at 1835 CST at Grand Gulf Nuclear Station, while the 208 ft. Containment Airlock Outer Door was tagged-out for planned maintenance, the 208 ft. Containment Inner Door was determined to be inoperable. Grand Gulf had performed 06-ME-1M23-R-0001, Personnel Airlock Door Seal Air System Leak Test, on the 208 ft. Containment Airlock Inner Door which had been deemed satisfactory. While performing planned maintenance on the outer door an additional review of the paperwork determined that the test was actually unsatisfactory on the inner door. TS 3.6.1.2 Condition C was entered at 1835 CST on 2/10/18 for both 208 ft. Containment Airlock Doors being inoperable. Maintenance of the Outer Door is expected to be completed, and the airlock returned to operable status, prior to TS required action completion time. The licensee notified the NRC Resident Inspector. |
| ENS 51457 | 6 October 2015 17:56:00 | At 1333 (CDT) on 10-6-2015, GGNS (Grand Gulf Nuclear Station) was notified by Claiborne County Civil Defense that the Public Notification System (ANS) Sirens in Claiborne County had been inadvertently initiated by Claiborne County at 1330 today. In response, GGNS informed Claiborne County, MS, State of Mississippi, Tensas Parish, LA, the State of Louisiana and other government agencies of a spurious actuation of the emergency response sirens in Claiborne County. The duration of the siren actuation was approximately 2 minutes. Upon cancellation of the siren activation command at 1332, the Claiborne County Emergency Director issued a 'NO EMERGENCY' message via CODE RED and Tone Alert Radio. At approximately 1342, Claiborne County Emergency Management Agency also faxed a 'NO EMERGENCY' Emergency Alert System message transmission request to the following television stations: WJMI, WLBT, and WJTV. The licensee stated Claiborne County technicians believed this was caused by human error. The Licensee notified the NRC Resident Inspector. |