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| Discovered date | Reporting criterion | Title | Description | LER | |
|---|---|---|---|---|---|
| ENS 57019 | 10 March 2024 08:53:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Essential Chilled Water Trains Declared Inoperable | The following information was provided by the licensee via email: On 3/9/2024 at 2126 CST, train C essential cooling water was declared inoperable due to a through-wall leak on the discharge vent line. This would also cascade and cause train C essential chilled water to be inoperable. On 3/10/2024 at 0353 CDT, train B essential chilled water was declared inoperable due to chilled water outlet temperature greater than 52 degrees F following startup of essential chiller 12B. Chilled water outlet temperature was adjusted to less than 52 degrees F at 0440 CDT, and train B essential chilled water was declared operable. This condition resulted in the inoperability of two of the three safety trains required for the accident mitigating functions including: high head safety injection, low head safety injection, containment spray, electrical auxiliary building HVAC, control room envelope HVAC, and essential chilled water. This is an 8 hour reportable condition per 10CFR50.72(b)(3)(v)(D) because it could affect the ability to mitigate the consequences of an accident. The licensee notified the NRC Resident Inspector. | |
| ENS 56944 | 24 January 2024 01:02:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Accident Mitigation - Relief Valves Inoperable | The following information was provided by the licensee via email: At 1640 CST on February 1, 2024, it was determined that a condition occurred that could have prevented the fulfillment of a safety function due to two of the four steam generator (SG) power-operated relief valves (PORVs) being simultaneously inoperable. In certain accident scenarios, more than two PORVs are needed to mitigate the consequences of an accident; therefore, this condition is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(v). The first PORV was declared inoperable at 1025 on January 22, 2024, and the safety function is considered to have been lost when the second PORV was declared inoperable at 1902 on January 23, 2024. The safety function was restored at 2234 on January 23, 2024, when the first SG PORV was declared operable. There was no impact to unit 2. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The plant remained in mode 3 for the duration of the condition. The causes for the two PORVs being inoperable were neither related nor systemic in nature. All SG PORVs have been restored to operation. | |
| ENS 56877 | 2 December 2023 12:10:00 | 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Specified System Actuation - Auto Start of Emergency Diesel Generator | The following information was provided by the licensee via email: At 0610 CST on 12/2/2023, with Unit 2 in Mode 1 at 100 percent power, the South Texas Project switchyard south electrical bus was de-energized. Emergency diesel generator (EDG) '22' automatically started in response to the loss of offsite power on the train 'B' engineered safety feature (ESF) electrical bus. This event is reportable under 10 CFR 50.72(b)(3)(iv)(A) as an event that resulted in the valid actuation of an emergency AC electrical power system (50.72(b)(3)(iv)(B)(8)). All required loads were successfully started. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The initial loss of the south electrical bus, partial loss of off-site power, put the plant in a 24 hour limiting condition for operation (LCO) in accordance with (IAW) technical specification (TS) 3.8.1.1.E. Power was restored to the train 'B' ESF bus via an alternate offsite power source and the EDG was returned to its automatic standby condition. Currently, the plant is in a 72 hour LCO IAW TS 3.8.1.1.A. | |
| ENS 56861 | 16 November 2023 21:41:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Essential Chiller Trains Inoperable | The following information was provided by the licensee via phone and email: 11/05/23, 2200 CST: Essential Chiller 'B' train and associated cascading equipment were declared INOPERABLE for planned maintenance. Unit 2 entered the Configuration Risk Management Program as required by Technical Specifications on 11/12/23 at 2200. 11/16/23, 1541: Essential Chiller 'C' train and associated cascading equipment were declared INOPERABLE due to an unexpected material condition causing the Essential Chiller to trip. The most limiting (Limiting Condition of Operability) LCO is 3.7.7, Action c. This condition resulted in the INOPERABILITY of two of the three safety trains required for the accident mitigating function including: High Head Safety Injection, Low Head Safety Injection, Containment Spray, Electrical Auxiliary Building HVAC, Control Room Envelope HVAC, Essential Chilled Water. This is an 8 hour reportable condition per 10CFR50.72(b)(3)(v)(D) because it could affect the ability to mitigate the consequences of an accident. A risk analysis was performed for the equipment INOPERABILITY and mitigating actions have been taken per site procedures. All 'A' train equipment remains operable. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The 'B' train Emergency Diesel Generator was also inoperable due to planned maintenance and continues to be inoperable. It was considered in the Configuration Risk Management Program and it was determined this condition could be maintained. LCO 3.7.7, Action c requires reactor shutdown within 72 hours. | |
| ENS 56848 | 10 November 2023 20:13:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | Essential Chiller Trains Inoperable | The following information was provided by the licensee via email: On 11/10/23 at 0642 CST, essential chiller 'B' train and cascading equipment was declared inoperable due to chill water temperature exceeding limits. At 1413 CST, essential chiller 'C' train and cascading equipment was declared inoperable due to discharge pressure exceeding limits. This condition resulted in an inoperable condition on two out of the three safety trains for the accident mitigating function including the 'B' and 'C' train high head safety injection, low head safety injection, containment spray, electrical auxiliary building HVAC, control room envelope HVAC, and essential chill water. All 'A' train equipment remained operable. This was determined to be reportable within 8 hours as required by 10 CFR 50.72(b)(3)(v)(D). The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: Plant is in a 72 hour limiting condition for operation per technical specification 3.7.7. Restoration of 'B' train anticipated on 11/11/23 mid day. | |
| ENS 56521 | 16 May 2023 21:30:00 | 10 CFR 26.719, FFD Reporting requirements | FITNESS-FOR-DUTY Violation | The following information was provided by the licensee via email: On May 16, 2023, it was determined that a licensed operator violated the station's FFD policy. The employee's unescorted access at South Texas has been terminated. This event was determined to be reportable under 10 CFR 26.719(b)(2)(ii). The NRC resident inspector has been notified. | |
| ENS 56439 | 30 March 2023 06:03:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification Due to ON-SITE Fatality | The following information was provided by the licensee via email: At approximately 0037 CDT on March 30, 2023, a non-responsive individual at South Texas Project (STP) Electric Generating Station was transported offsite for treatment at an offsite medical facility. The offsite medical facility notified STP Nuclear Operating Company that the individual had been declared deceased as of 0103 CDT. The fatality was not work-related, and the individual was outside of the radiologically controlled area. This event is reportable in accordance with 10 CFR 50.72(b)(2)(xi) as a four-hour, non-emergency notification for an on-site fatality and notification of another government agency. OSHA will be notified. The NRC Resident Inspector has been notified. | |
| ENS 56117 | 19 September 2022 11:50:00 | 10 CFR 26.719, FFD Reporting requirements | Fitness for Duty (FFD) Report - NON-LICENSED Supervisor Violated FFD Policy | The following information was provided by the licensee via email: On September 19, 2022, a non-licensed supervisor violated the station's FFD policy. The employee's unescorted access at South Texas has been terminated. This event was determined to be reportable under 10 CFR 26.719(b)(2)(ii). The NRC resident inspector has been notified. | |
| ENS 56094 | 28 July 2022 22:05:00 | 10 CFR 50.73(a)(1), Submit an LER | Invalid System Actuation | The following information was provided by the licensee via fax: Auxiliary Feedwater Pump #12 actuation and isolation of the Steam Generator Blowdown for 'A', 'B' and 'C' Steam Generators. Per 10 CFR 50.73(a)(1), the telephone notification is made under 10 CFR 50.73(a)(2)(iv)(A) for an invalid actuation. On 7/28/2022 at 1705 CDT, the Unit 1 Control Room received alarm SPQD0183 'SG LO-LO LVL TRN B ACT' and actuation of the Auxiliary Feedwater Pump #12 and isolation of the Steam Generator Blowdown for 'A', 'B' and 'D' Steam Generators. This event was classified as an unplanned entry into Technical Specification Shutdown LCO equal to or less than 24 hours 'Simple Restoration', due to the availability of CRMP. This alarm occurred several times and with each occurrence the alarm was short lived (1 second or less). Operations placed Auxiliary Feedwater Pump #12 in the Pull-To-Lock position to prevent starting of the pump with each alarm occurrence. During troubleshooting it was determined that SSPS Logic 'R' train was generating the intermittent alarm condition. A Logic board and a Safeguard Driver board were replaced which was identified as the possible cause. Operations performed applicable sections of the Logic test to ensure SSPS 'R' train operable. The event had no effects/consequences on the unit. The Logic board and Safeguard Driver board in SSPS 'R' train were both replaced as the possible causes, and therefore both boards were sent to Westinghouse to determine which board was at fault. The NRC Resident Inspector has been notified. | |
| ENS 55918 | 25 May 2022 18:54:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification for Inadvertent Discharge of Halon | The following information was provided by the licensee via email: On 5/25/2022 at 1354 (CDT), during the replacement of two detectors, a halon actuation occurred which resulted in an unintentional release of approximately 384 pounds of halon gas into an enclosed room in the Unit 1 Electrical Auxiliary Building. There was no impact to plant operations or plant personnel. The room was verified by station Safety Personnel to be safe for normal access. On 5/27/2022 at 2038 (CDT), Region 12 (Houston) of the Texas Commission of Environmental Quality (TCEQ) was notified of an event which met the requirements of "Emission Event" for the TCEQ of a halon release that exceeded the reportable quantity threshold of 100 pounds in a 24 hour period. The halon discharge was contained within the site protected area. Therefore, this event is not significant with respect to the health and safety of the public. The licensee has notified the NRC Resident Inspector. | |
| ENS 55692 | 6 January 2022 12:03:00 | 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Specified System Actuation - Auto Start Emergency Diesel Generator | At 0603 CST on 1/6/2022, with Unit 2 in Mode 1 at 100 percent power, the South Texas Project (STP) south switchyard electrical bus was de-energized momentarily and re-energized approximately 40 seconds later. Emergency Diesel Generators (EDG) 22 automatically started in response to loss of offsite power on Train B Engineered Safety Feature (ESF) Bus. This event is reportable under 10 CFR 50.72(b)(3)(iv)(A) as an event that resulted in the valid actuation of an emergency AC electrical power system (50.72(b)(3)(iv)(B)(8)). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: Unit 2 is in a 72 hour LCO per TS 3.8.1.1.A for the loss of one offsite power supply. The plant is in a normal electrical lineup. There was no impact on Unit 1. | |
| ENS 55398 | 5 August 2021 22:42:00 | 10 CFR 26.719, FFD Reporting requirements | NON-LICENSED Supervisory Personnel Violated FFD Policy | A non-licensed supervisor had a confirmed positive for alcohol during a random fitness-for-duty test. The employee's access to the plant has been terminated. The NRC Resident Inspector has been notified. | |
| ENS 55440 | 4 August 2021 17:00:00 | 10 CFR 26.719, FFD Reporting requirements | Licensed Operator Violated FFD Policy | On August 4, 2021 a Licensed Reactor Operator violated the station's FFD policy. The employee's unescorted access to South Texas has been terminated. The event was determined to be reportable under 10 CFR 26.719(b)(2)(ii). The NRC Resident Inspector will be been notified. | |
| ENS 55338 | 3 July 2021 18:30:00 | 10 CFR 26.719, FFD Reporting requirements | Controlled Substance Discovered within the Protected Area | On July 03, 2021, at approximately 1011 CDT, a Security Force Supervisor at South Texas Project Electric Generating Station (STPEGS) was informed by a security officer that they had located what appeared to be drug paraphernalia inside the Protected Area. At 1033 CDT Local Law Enforcement was contacted and responded to STPEGS. At 1130 CDT the Matagorda County Sheriff's office took the item into evidence for testing to determine if there was any presence of a controlled substance. At 1311 CDT, the Matagorda County Sheriff's office notified STP Nuclear Operating Company (STPNOC) that the item tested positive for the presence of a controlled substance. At 1330 CDT the Unit 1 Shift Manager was notified. This event is being reported in accordance with 10 CFR 26.719(b)(1) for discovery or presence of illegal drugs within the protected area. STPNOC is continuing to investigate this incident. The Resident Inspector has been notified. | |
| ENS 55256 | 13 May 2021 15:45:00 | 10 CFR 26.719, FFD Reporting requirements | Fitness for Duty Report | A non-licensed temporary supervisor had a confirmed positive during a random fitness-for-duty test. The employee's access to the plant has been terminated. The NRC Resident Inspector has been notified. | |
| ENS 55104 | 15 February 2021 11:26:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation | Automatic Reactor Trip Due to Low Steam Generator Level | At 0526 (CST) on 02/15/2021, Unit 1 automatically tripped due to low steam generator levels. The low steam generator levels were due to loss of Feedwater pumps 11 and 13 (cause unknown). Auxiliary Feedwater and Feedwater Isolation actuated as designed. All Control and Shutdown Rods fully inserted. No primary or secondary relief valves opened. There were no electrical problems. Normal operating temperature and pressure (NOT/NOP) is 567 degrees F and 2235 psig. There were no significant TS LCOs entered. This event was not significant to the health and safety of the public based on all safety systems performed as designed. Unit 2 was not affected. Decay heat removal is being controlled via Steam Dumps. (Auxiliary Feedwater is supplying water to the Steam Generators.) Offsite power is in the normal electrical lineup. The NRC Resident inspector has been notified. Unit 2 was not affected and remains at 100% power. | |
| ENS 55053 | 30 December 2020 21:50:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification Due to Inadvertent Emergency Siren Activation | On December 30, 2020 at 1550 CST, South Texas Project (STP) received a report that two Emergency Notification System sirens inadvertently actuated. The sirens were heard by residents in the area who contacted the Matagorda County Sheriff's office, which notified the Emergency Response Division at STP of the siren actuation at 1557 CST. Both sirens were initially restored, however siren #24 subsequently actuated again at 1735 CST. Siren #24 has been disconnected. Siren #27 remains available. Thirty-one of thirty-two sirens are available. This notification is being made under 10CFR50.72(b)(2)(xi) as an event where other government agencies were notified. The sirens are no longer alarming. A social media release is planned. The NRC Resident Inspector has been notified of the event. The licensee believes the sirens actuated due to significant rain in the area but will be investigating the cause of the inadvertent actuation. | |
| ENS 54714 | 14 May 2020 21:10:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification for Hydraulic Oil Release | At 1535 CDT, on 5/14/2020, it was determined that approximately 10 gallons of hydraulic oil was spilled during dredging activities into the STP Intake Basin (adjacent to the Colorado River). Cleanup using oil booms is underway and there is no longer a visible sheen. The cause of the hydraulic oil spill is under investigation. The Texas General Land Office was notified at 1610 CDT. The NRC Resident Inspector has been notified. | |
| ENS 54605 | 24 March 2020 15:46:00 | 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Specified System Actuation - Auto Start Emergency Diesel Generators | At 1046 CDT on 3/24/2020, with Unit 1 defueled and Unit 2 in Mode 1 at 100 percent power, the South Texas Project (STP) South switchyard electrical bus was deenergized. This resulted in a loss of power to Standby Transformer 2 which was supplying power to the Engineered Safety Features (ESF) 4160v busses for Unit 1 A- and C-Trains, and Unit 2 B-Train. Emergency Diesel Generators (EDGs) 11, 13, and 22 automatically started in response to the undervoltage condition. The cause for the loss of the South switchyard electrical bus was an error in relay testing in the switchyard. This event is reportable under 10 CFR 50.72(b)(3)(iv)(A) as an event that resulted in the valid actuation of emergency AC electrical power systems (50.72(b)(3)(iv)(B)(8)) as well as the Unit 1 A- and C-Train and Unit 2 B-Train Reactor Containment Fan Coolers (50.72(b)(3)(iv)(B)(7)) and Unit 2 B-Train Auxiliary Feedwater pump (50.72(b)(3)(iv)(B)(6)). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. | |
| ENS 54587 | 17 March 2020 20:58:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Notification to Other Government Agency | At 1532 CDT, on 3/17/2020, it was reported to the Unit 1 Control Room that less than one gallon of hydraulic oil was spilled into the Colorado River during dredging activities. Cleanup using oil booms was completed at 1747 CDT. The cause of the hydraulic oil spill is under investigation. The Texas General Land Office was notified at 1558 CDT. The NRC Resident Inspector has been notified. | |
| ENS 54561 | 4 March 2020 13:18:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | EN Revision Imported Date : 3/6/2020 NOTIFICATION TO OTHER GOVERNMENT AGENCY On March 4, 2020, an actual Unusual Event code was inadvertently sent to an offsite agency, Institute of Nuclear Power Operations (INPO), and to a former NRC Resident Inspector during a planned emergency response drill. The NRC Resident Inspector has been notified.
Based on further review of the NRC reporting guidance relative to these criteria, STP has concluded that this condition is below the reporting threshold outlined in NUREG-1022 Revision 3. NUREG-1022 states the following (page 54): 'Licensees generally do not have to report media and government interactions unless they are related to the radiological health and safety of the public or on-site personnel, or protection of the environment. The condition originally reported in EN 54561 is not a news release or government notification and has no impact on the radiological health and safety of the public or on-site personnel, or protection of the environment. Therefore, STP is retracting EN 54561. The NRC Resident Inspector was notified on 3/5/2020 at 1310 CST. Notified R4DO Rick Deese. | ||
| ENS 54556 | 2 March 2020 20:52:00 | 10 CFR 26.719, FFD Reporting requirements | Fitness-For-Duty Report - Contract Supervisor Confirmed Positive Test | A non-licensed contract employee supervisor had a confirmed positive for illegal drugs during a random fitness-for-duty test. The employee's access to the plant has been terminated. The licensee notified the NRC Resident Inspector. | |
| ENS 54530 | 18 February 2020 15:15:00 | 10 CFR 26.719, FFD Reporting requirements | Non-Licensed Supervisory Personnel Violated Ffd Policy | On February 18, 2020 a non-licensed contractor supervisor violated the station's FFD policy. The employee's unescorted access to South Texas has been terminated. The NRC Resident Inspector has been notified. | |
| ENS 54529 | 17 February 2020 23:17:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Notification to Other Government Agency | At 1647 CST on 2/17/2020, it was determined that approximately two quarts of hydraulic oil were spilled into the Colorado River during preparation for dredging activities. Cleanup using an oil dispersant and oil booms is underway. The cause of the hydraulic oil spill is under investigation. The Texas General Land Office was notified at 1717 CST. Additional reports were made to the Texas Commission of Environmental Quality, the Environmental Protection Agency National Response Center, and the Matagorda County Local Emergency Planning Committee. The NRC Resident Inspector has been notified. | |
| ENS 54517 | 11 February 2020 16:07:00 | 10 CFR 26.719, FFD Reporting requirements | Fitness-For-Duty Report - Policy Violation | On February 11, 2020, a licensed Senior Reactor Operator violated the station's fitness-for-duty policy. The employee's access to South Texas has been terminated. The NRC Resident Inspector has been notified. The employee tested positive on a follow-up test for alcohol. | |
| ENS 54502 | 30 January 2020 17:45:00 | 10 CFR 26.719, FFD Reporting requirements | Fitness-For-Duty - Contractor Supervisor Violated the Ffd Policy | On January 30, 2020, a non-licensed contractor supervisor had a confirmed positive for alcohol during a for-cause fitness-for-duty test. The employee's unescorted access to the plant has been terminated. The NRC Resident Inspector has been notified.
The initial NRC report wording was incorrect. Specifically, the non-licensed supervisory personnel violated the fitness for duty policy, they did not have a confirmed positive for-cause fitness-for-duty test. The title of this event is corrected. Notified R4DO (Taylor) and FFD Group. | |
| ENS 54351 | 25 October 2019 01:51:00 | 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Valid Undervoltage Actuation During Edg Sequencer Maintenance | On October 24, 2019, at 2051 Central Time, while performing Train C Sequencer maintenance, a valid undervoltage actuation signal was sent to Unit 2 Emergency Diesel Generator (EDG) 23. The ESF Train C bus loads were shed but EDG 23 did not automatically start because it had been placed in Pull-To-Stop to support the sequencer maintenance activities. EDG 23 was taken out of Pull-To-Stop by Control Room staff to allow it to auto start and load the bus. As a result of the bus strip signal, the in service Spent Fuel Pool Cooling Pump secured. Spent Fuel Pool Cooling was restored with no measurable increase in pool temperature. The reactor was not critical and reactor decay heat removal was not challenged throughout the event. This actuation is reportable per 10 CFR 50.72(b)(3)(iv)(A) due to the automatic actuation of a system listed in 10 CFR 50.72(b)(3)(iv)(B). The NRC Resident Inspector has been notified. | |
| ENS 54284 | 18 September 2019 12:50:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Communication with Emergency Operations Facility | At 0750 CDT, on September 18, 2019, South Texas Project Electric Generating Station (STPEGS) experienced an unplanned loss of the Integrated Computer System (ICS) to the Emergency Operations Facility (EOF). The loss of ICS resulted in a major loss of emergency assessment capability to the STPEGS EOF for greater than 90 minutes. Assessment capability has been verified to be available in the Unit 2 Technical Support Center (TSC) and the Unit 1 and Unit 2 Control Rooms. ICS was restored to the EOF at 0932 CDT on September 18, 2019. This report is being made pursuant to 10 CFR 50.72(b)(3)(xiii) as any event that resulted in a major loss of emergency assessment capability, offsite response capability, or offsite communications capability. There was no impact to the health and safety of the public or plant personnel. The NRC Resident Inspector has been informed. | |
| ENS 54257 | 6 September 2019 02:15:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident 10 CFR 50.72(b)(3)(ii)(B), Unanalyzed Condition 10 CFR 50.72(b)(3)(v)(C), Loss of Safety Function - Release of Radioactive Material | En Revision Imported Date 11/8/2019 | EN Revision Text: CONTAINMENT PENETRATION DISCOVERED NOT ISOLATED At 2115 CDT on 9/5/2019, an inside containment test connection and inoperable outside containment isolation valve were discovered to be open for a containment air sample penetration. This resulted in the containment penetration not being isolated. The inside containment test connection was closed at 2322 CDT on 9/5/2019. This event is being reported under 10 CFR 50.72(b)(3)(v)(C) and (D) and 10 CFR 50.72(b)(3)(ii)(B). There was no impact to the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified.
This event was originally reported on September 6, 2019 under 10 CFR 50.72(b)(3)(v)(C) and (D) and 10 CFR 50.72(b)(3)(ii)(B). Upon completion of the investigation of the event, it was determined that the event had insignificant safety consequences because the containment breach was disconnected from the Reactor Coolant System by a series of closed valves for the duration of the event. Additionally, the lines to the inside containment connection and the outside inoperable containment isolation valve that was found to be open as well as the main line connecting and passing through the penetration were one-inch diameter lines. Analysis determined that containment breaches that are less than a three-inch diameter do not lead to a large radiation release. The event did not place the plant in an unanalyzed condition that significantly degrades plant safety. Therefore, 10 CFR 50.72(b)(3)(ii)(B) did not apply to this event and this notification is to retract reporting under that criterion. The licensee notified the NRC Resident Inspector. Notified R4DO (Drake). | |
| ENS 54190 | 30 July 2019 20:21:00 | 10 CFR 50.72(b)(3)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident | En Revision Imported Date 8/22/2019 | EN Revision Text: DISCOVERY OF CONDITION THAT COULD HAVE PREVENTED FULFILLMENT OF A SAFETY FUNCTION South Texas Project (STP) Unit 1 reactor head vent valve B1RCHCV0601 was declared inoperable on December 29, 2018, STP Unit 1 reactor head vent valve B1RCHCV0602 was declared inoperable on July 30, 2019. Technical Specification 3.3.3.5 requires one of two reactor head vent valves to be operable. This issue placed the plant in a 30-day Technical Specification Action. At 0741 CDT on July 31, 2019, South Texas Project Electric Generating Station (STPEGS) made a determination based on firm evidence that reactor head vent valve B1RCHCV0602 had been inoperable since June 24, 2019. This results in a condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident. This report is being made pursuant to 10 CFR 50.72(b)(3)(v)(D), '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 inoperable equipment is required for accident conditions and presents no danger to the health and safety of the public or the safe operation of the units. The NRC Resident Inspector has been notified.
The Event Date and Time provided in EN# 54190 should have been reported as 7/30/2019 at 1521 CDT, since this was the time of discovery of a condition that could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident. The NRC Resident Inspector has been notified. Notified R4DO (Young). | |
| ENS 54145 | 3 July 2019 15:26:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Offsite Notification Due to Radio Transmitter Out of Service | At 1026 CDT on July 3, 2019, the National Weather Service notified the South Texas Project (STP) that the Bay City NOAA radio transmitter was out of service. This affects the tone alert radios used to notify the public in the event of an emergency condition. This condition impacts the ability to readily notify a portion of the Emergency Planning Zone (EPZ) population for the STP Electric Generating Station. The loss of the alert radio system meets the reporting criterion for 10 CFR 50.72(b)(3)(xiii). The Matagorda County alert sirens, which are also part of the Public Prompt Notification System, remain operable. Compensatory measures have been verified to be available should the Prompt Notification System be needed. These measures consist of a reverse 911 system available from Matagorda County as well as local law enforcement personnel who would perform route alerting for the affected areas of the EPZ. The event has been entered into the Corrective Action Program and the NRC Resident Inspector has been notified. A return to service time for the radio transmitter is not currently available. Matagorda County was also notified by the National Weather Service and STP. This meets the reporting requirement for notification of an offsite agency, 10 CFR 50.72(b)(2)(xi).
At 1321 CDT, the National Weather Service communication tower was returned to service. South Texas Project verified that the automatic notification radios have been returned to service. The licensee has notified the NRC Resident Inspector. Notified R4DO (Haire). | |
| ENS 54097 | 1 June 2019 21:18:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification Due to Gasoline Leakage to Site Drainage System | On June 1,2019, at 1618 (CDT), a notification under 10 CFR 50.72(b)(2) is being made due to notification to offsite agencies as a result of gasoline leakage to the site drainage system in the owner controlled area at South Texas Project. During a routine tour, the facilities department notified the site environmental group about a gasoline leak on fuel tank sight glass at the fuel island on site. The site environmental (group) has determined the leak amount requires notification to the Texas Commission of Environmental Quality and the Environmental Protection Agency National Response Center. The Texas Commission of Environmental Quality was notified at 1618 on June 1, 2019, and the Environmental Protection Agency National Response Center at 1626 on June 1, 2019. The NRC Resident Inspector has been notified. The licensee stated that approximately 1,384 gallons of gasoline leaked over a period of time. The spill is located at an equipment warehouse area at a distance from the plant. The leak has been isolated and the cleanup is expected to be completed by tomorrow. | |
| ENS 54024 | 23 April 2019 17:56:00 | 10 CFR 26.719, FFD Reporting requirements | Fitness for Duty Report - Algorithm Used for Random Testing Excluded a Population of Individuals | On April 23, 2019, at 12:56 Central Time, South Texas Project Nuclear Operating Company (STPNOC) identified a programmatic failure, degradation, or discovered vulnerability of the fitness for duty (FFD) program that may permit undetected drug or alcohol use or abuse by individuals within a protected area, or by individuals who are assigned to perform duties that require them to be subject to the FFD program. The NRC Resident Inspector has been notified. | |
| ENS 53656 | 9 October 2018 05:00:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Unplanned Loss of Emergency Response Equipment | At 2115 CST on October 9, 2018, South Texas Project Electric Generating Station (STPEGS) experienced an unplanned loss of the Integrated Computer System (ICS) to the Emergency Operations Facility (EOF). The loss of ICS resulted in a major loss of emergency assessment capability to the STPEGS Emergency Operations Facility (EOF) for greater than 75 minutes. Assessment capability has been verified to be available in the Unit 1 and Unit 2 Technical Support Centers (TSC) and the Unit 1 and Unit 2 Control Rooms. This report is being made pursuant to 10 CFR 50.72(b)(3)(xiii), any event that results in a major loss of emergency assessment capability, off site response capability, or off site communications ability. The NRC Resident Inspector has been informed. The cause of the unplanned loss is currently being investigated and compensatory measures are in place.
Integrated Computer System was returned to service as of 0810 CDT on October 10, 2018. Notified R4DO (Gepford) and CAT via email. | |
| ENS 53405 | 17 May 2018 03:02:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification of Fires in the Owner Controlled Area | On May 16, 2018 at approximately 1425 CDT, two grass fires started in the Owner Controlled Area surrounding South Texas Project (STP) Nuclear Generating Station. The Bay City Volunteer Fire Department was called to the site to fight the fire. Reinforcements from Tres Palacios Oaks, Midfield and Markham Fire Departments were called in to assist with firefighting efforts. The grass fires were extinguished on May 16, 2018 at 2046 CDT. The fires occurred outside the protected area of the plant and presented no danger to the public or the safe operation of the units. On May 16, 2018 at 2202 CDT, STP Nuclear Generating Station issued a press release to inform area residents. The licensee notified the NRC Resident Inspector.
On May 17, 2018, at 11:10 CDT STP Nuclear Generating Station notified the Texas Commission on Environmental Quality (TCEQ) of the grass fires, resulting in visible emissions, that occurred in the Owner Controlled Area of the STP Nuclear Generating Station on May 16, 2018, between the times of 14:25 and 20:46 CDT. No further press releases are planned. The licensee notified the NRC Resident Inspector. Notified R4DO (Gepford). | |
| ENS 53141 | 1 January 2018 16:15:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification - Emergency Notification Siren Inadvertent Actuation | A South Texas Project Offsite Emergency Notification siren (#7) was inadvertently going off. The Matagorda County Sheriff's office notified the Emergency Response Organization at the station of the siren actuation. Station personnel are addressing the issue with the siren. The Matagorda County Sheriff's office was the only offsite agency that was contacted during this event. This notification is being made under 10CFR50.72(b)(2)(xi) as an event where other government agencies were notified. The licensee has personnel at the siren which is no longer alarming (1.5 hours after alarm notification). The licensee notified the NRC Resident Inspector | |
| ENS 53118 | 12 December 2017 23:57:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Unplanned Loss of Emergency Response Equipment | At 1757 CST on December 12, 2017, South Texas Project Electric Generating Station (STPEGS) Unit 1 and Unit 2 experienced an unplanned partial loss of the Integrated Computer System (ICS). The partial loss of Unit 1 and Unit 2 ICS resulted in a major loss of emergency assessment capability to STPEGS Unit 1 and Unit 2 Technical Support Center (TSC) for greater than 75 minutes. Assessment capability has been verified to be available in the Emergency Operations Facility (EOF). This report is being made pursuant to 10 CFR 50.72(b)(3)(xiii), any event that results in a major loss of emergency assessment capability, off site response capability, or off site communications ability. The NRC Resident Inspector has been informed. | |
| ENS 53116 | 12 December 2017 21:19:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification Due to Inadvertent Actuation of Emergency Notification Siren | A South Texas Project (STP) Offsite Emergency Notification Siren (#7) was inadvertently going off. A resident who lived near the siren notified the Matagorda County Sheriff's Office at 0905 CST of the event and subsequently left a message with the STP Emergency Response staff. The Emergency Response staff dispatched maintenance to repair the siren and then later notified the Control Room at 1519 CST that the Sheriff's department was notified. The siren was inspected and reset. No issues were found with the siren. The Matagorda County Sheriff's Office was the only offsite agency that has been notified. The NRC Resident Inspector has been notified. | |
| ENS 52911 | 17 August 2017 19:42:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Non Work Related Onsite Fatality | At 1315 Central Daylight Time (CDT) on 8/17/2017, the South Texas Project Unit 1 Control Room was notified that a contract employee had experienced a non-work-related medical emergency within the Protected Area. The individual was transported to Matagorda Regional Medical Center in Bay City, TX. At 1442 CDT, the Unit 1 Control Room was notified that the patient was declared deceased. The Occupational Safety and Health Administration (OSHA) will be notified. This notification is being made under 10CFR50.72(b)(2)(xi) as an event for which another government agency is being notified. The deceased individual was not radioactively contaminated. The NRC Senior Resident Inspector has been notified. | |
| ENS 52775 | 30 May 2017 14:29:00 | 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Loss of Emergency Operations Facility Integrated Computer System Data for Planned Maintenance | On May 30, 2017 at 0929 (CDT), South Texas Project (STP) removed from service Integrated Computer System (ICS) connections to the Emergency Operations Facility (EOF) for planned maintenance. The ICS computers are used in the EOF to directly monitor selected plant parameters and to provide Emergency Response assessment capabilities. This planned maintenance implements a software modification and is expected to last for four days. This is reportable under 10 CFR 50.72(b)(3)(xiii) because the EOF assessment capabilities would not be able to be restored within the facility activation time and assessment capabilities cannot be performed at a backup facility (i.e., there is no backup EOF). While ICS connections in the EOF are out of service, if the Emergency Plan is entered and the Technical Support Center (TSC) and EOF are staffed, the EOF will not activate and Emergency Director authority will remain in the TSC. The Emergency Response Organization team members that report to the EOF and TSC have been notified regarding the status of the ICS computers in the EOF. The planned modification that impacts the ICS computers in the EOF does not affect the health and safety of the public or station employees. The NRC Resident Inspector has been notified. The licensee notified the Matagorda County Sheriff, and the State of Texas Department of Public Safety and the Department of State Health Services. | |
| ENS 52733 | 5 May 2017 02:03:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification Due to Miscommunication During On-The-Job Training | On 5/4/17 at 2103 CDT, the South Texas Project (STP) Security Department was conducting on-the-job training for Bomb Threat response. While simulating the Bomb Threat Checklist via phone call, the trainer mistakenly contacted the Brazoria County, TX Child Protective Services (CPS) and reported a bomb threat. In response, the Child Protective Services notified the City of Brazoria, TX Police Department of the threat. The Brazoria Police Dept. then contacted both the Bay City, TX Police Department and the STP Security Department. By approximately 2130 CDT, all agencies had been notified by the STP Security Department of the mistaken phone call and that no actual bomb threat existed. The NRC Senior Resident Inspector was notified of the issue. | |
| ENS 52716 | 29 April 2017 21:23:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification Due to Small Grass Fire in Owner Controlled Area | A grass fire was reported to the Unit 1 control room at 1102 CDT. The grass fire was reported to be in the owner controlled area 1/2 mile west of the protected area and switchyard. The local fire department was dispatched to fight the grass fire. The fire was reported to be out at 1155 CDT. No plant equipment was damaged and the operation of the plant was not affected. Region 12 (Houston) of the Texas Commission of Environmental Quality (TCEQ) was notified of the event at 1623 CDT for visible emissions resulting from the grass fire. No further actions are required by the TCEQ at this time and no press release is planned. An insulator on a 345 kV line failed and the attached line separated and hit the ground. A spark was created when the 345 kV line hit the ground and started a fire that eventually grew to a 20 feet x 20 feet area. The licensee notified the NRC Resident Inspector. | |
| ENS 52583 | 28 February 2017 16:30:00 | 10 CFR 26.719, FFD Reporting requirements | Fitness for Duty - Prohibited Item Found Inside Protected Area | Event Report per 10 CFR 26.719(b)(1). On February 28, 2017, a violation of the site Fitness For Duty policy was committed. A prohibited item was found inside the Protected Area. The licensee notified the NRC Resident Inspector. | |
| ENS 52303 | 18 October 2016 22:50:00 | 10 CFR 26.719, FFD Reporting requirements | Fitness for Duty | A non-licensed supervisory employee had a confirmed positive for alcohol during a random fitness-for-duty test.. Unescorted access to the plant has been denied. The licensee notified the NRC Resident Inspector. | |
| ENS 52142 | 1 August 2016 20:18:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Unintentional Release of Halon | At 1118 (CDT) during planned maintenance activities there was an unintentional release of approximately 146.5 pounds of Halon gas into an enclosed room in the Unit-2 Electrical Auxiliary Building. There was no impact to plant operations or plant personnel. The room was verified by station Safety Personnel to be safe for normal access. At 1518, Region 12 (Houston) of the Texas Commission of Environmental Quality (TCEQ) was notified of an event which met the requirements of 'Emission Event' for the TCEQ of a HALON release that exceeded the reportable quantity threshold of 100 pounds in a 24 hour period. No further actions are required by the TCEQ at this time and no press release is planned. The halon discharge was contained within the site protected area. Therefore, this event is not significant with respect to the health and safety of the public. The licensee has notified the NRC Resident Inspector. | |
| ENS 52106 | 13 July 2016 16:00:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Exercise Press Releases Aired on Radio as an Actual Event | During the planned NRC/FEMA evaluated drill exercise on 7/13/16, two press releases written in the Joint Information Center (JIC) were published in the Public Information and Emergency Response (PIER) system without 'THIS IS A DRILL' denoted at the top of the page. The original press release was stamped with 'THIS IS A DRILL' at the top of page 1 and at the bottom of page 2. When it was added into the PIER system for publication/faxing, it was not noticed the top of the document denoting 'THIS IS A DRILL' was cut off. The local radio station affiliate was not aware of STP's (South Texas Project's) exercise on 7/13/16. As a result, the affiliate station thought it was a real event and read the press releases over the airwaves at 1014 (CDT) and again at 1046 (CDT). At approximately 1400 (CDT) on the same day, the radio station told their listening audience of the mistake and stated STP was having a training exercise not a real event. The correction was broadcast over the airwaves three times every hour until midnight. This unplanned media event is being reported in accordance with 10CFR50.72(b)(2)(xi). This event is not significant with respect to the health and safety of the public. The licensee notified the NRC Resident Inspector. | |
| ENS 51964 | 28 May 2016 01:46:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification Due to an Inadvertent Actuation of One Emergency Siren | A South Texas Project offsite emergency notification siren was inadvertently going off. The Matagorda County Sheriff's Office notified Site Security that a siren had actuated. At the time of the inadvertent siren actuation the area was experiencing lightning and rain. Suspect lightning caused the inadvertent siren actuation. Station Personnel are addressing the issue with the siren. The Matagorda County Sheriff's Office was the only offsite agency that was contacted during the event. The licensee has notified the NRC Resident Inspector. | |
| ENS 51897 | 2 May 2016 01:21:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Automatic Reactor Trip Due to Generator Lockout | At 2021 (CDT) on 05/01/2016 Unit 1 automatically tripped due to a generator lockout. Relay 86/G1 actuated. The generator lockout resulted in a Unit 1 turbine trip and a reactor trip. Auxiliary Feedwater and Feedwater Isolation actuated as designed. All Control Rods fully inserted. No primary or secondary relief valves opened. There were no electrical problems. Normal operating temperature and pressure is (being maintained). There were no significant TS LCO's entered. This event was not significant to the health and safety of the public based on all safety systems performed as designed. Unit 2 was not affected. Unit 1 is stable in Mode 3, with decay heat being removed via dump valves to the condenser. The cause of the generator lockout is under investigation. The licensee notified the NRC Resident Inspector. | |
| ENS 51787 | 14 March 2016 07:47:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification Due to Inadvertent Actuation of Offsite Emergency Notification Siren | A South Texas Project, Offsite Emergency Notification Siren, was inadvertently going off. The Matagorda County Sheriff's Office notified Site Security that a siren had actuated for no apparent reason. Station personnel are addressing the issue with the siren. The Matagorda County Sheriff's Office was the only offsite agency that was contacted during the event. The siren was tested and is considered functional at this time. Additional testing will be completed during daylight hours. The licensee will notify the NRC Resident Inspector. | |
| ENS 51687 | 27 January 2016 05:25:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Manual Reactor Trip Due to Loss of Feedwater to a Single Steam Generator | At 2325 (CST) on 01/26/2016, Unit 1 was manually tripped due to loss of Feedwater on 'C' S/G (Steam Generator). The loss of Feedwater was a result of a failure on 'C' S/G Main Feedwater Regulating Valve that caused the valve to travel closed with no Operator action. Auxiliary Feedwater and Feedwater Isolation actuated as designed. All Control and Shutdown Rods fully inserted. Intermediate Range Nl 36 (Nuclear Instrument) failed above P10 and, as a result, Source Range Nuclear Instruments were manually energized. No primary or secondary relief valves opened. There were no electrical problems. Normal operating temperature and pressure (NOT/NOP) is 567 degrees F and 2235 psig. There were no significant TS LCOs entered. This event was not significant to the health and safety of the public based on all safety systems performed as designed. Unit 2 was not affected. Decay heat removal is being controlled via Steam Dumps. Offsite power is in the normal electrical lineup. The NRC Resident Inspector has been notified. |