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| Entered date | Event description | |
|---|---|---|
| ENS 55086 | 29 January 2021 02:43:00 | This is an eight-hour, non-emergency notification for a loss of Emergency Assessment Capability. This event is reportable in accordance with 10 CFR 50.72(b)(3)(xiii) because the Technical Support Center (TSC) Supply Fan belt had failed which affects the functionality of an emergency response facility. Corrective maintenance activities are being performed on January 29, 2021 to the TSC HVAC (heating, ventilation, and air conditioning system). The work includes replacing the failed belt and restarting the TSC Supply Fan. The work duration is approximately 12 hours. If an emergency is declared requiring TSC activation during this period, the TSC will be staffed and activated using existing emergency planning procedures unless the TSC becomes uninhabitable due to ambient temperature, radiological, or other conditions. If relocation of the TSC becomes necessary, the Emergency Director will relocate the TSC staff to an alternate location in accordance with applicable site procedures. The Emergency Response Organization team has been notified of the maintenance and the possible need to relocate during an emergency. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. The licensee will be notifying the Illinois Emergency Management Agency. |
| ENS 53219 | 17 February 2018 10:29:00 | This report is being made in accordance with 10 CFR 50.72(b)(3)(v)(D) for an event or condition that could have prevented fulfillment of a safety function needed to mitigate the consequences of an accident. While troubleshooting an issue with the Unit 1B Diesel Generator Oil Circulating pump, damage of a bus bar was identified at the breaker that supplies the Unit 1B Diesel Generator Auxiliaries. One of the loads fed from this breaker is the Division 3 DC Battery Charger. It has been determined that the degradation of the bus bar may have prevented the Division 3 DC Battery Charger from performing its function which could have prevented the High Pressure Core Spray System (HPCS) from performing its design safety function. Since HPCS is a single train safety system, it has been determined that this failure could potentially affect the safety function of this system, and is reportable as an 8 hour notification. The NRC Resident Inspector has been notified. |
| ENS 53213 | 15 February 2018 13:39:00 | On February 15, 2018, during evaluation of protection for Technical Specifications (TS) equipment from the damaging effects of tornado generated missiles, LaSalle Station identified a non-conforming condition in the plant design such that specific TS equipment is considered to not be adequately protected from tornado generated missiles. Tornado generated missiles could strike the components supporting the operation of Control Room (VC) and Auxiliary Electric Room (VE) ventilation. This could result in inoperable VC/VE systems, which provide a protected environment for occupants to control the unit following an uncontrolled release of radioactivity, hazardous chemicals, or smoke if a tornado were to occur. This condition is reportable in accordance with 10 CFR 50.72(b)(3)(ii)(B) as a condition that results in the nuclear power plant being in an unanalyzed condition that significantly degrades plant safety and 10 CFR 50.72(b)(3)(v)(D) as a 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. This condition is being addressed in accordance with NRC enforcement guidance provided in Enforcement Guidance Memorandum (EGM) 15-002, Revision 1, 'Enforcement Discretion for Tornado-Generated Missile Protection Noncompliance,' and DSS-ISG-2016-01, Revision 1, 'Clarification of Licensee Actions in Receipt of Enforcement Discretion' per Enforcement Guidance Memorandum EGM 15-002, 'Enforcement Discretion for Tornado Generated Missile Protection Noncompliance.' Compensatory measures have been implemented in accordance with these documents. The NRC Resident Inspector has been informed of this notification. |
| ENS 50674 | 12 December 2014 18:20:00 | This report is being made pursuant to 10CFR50.72(b)(3)(v)(C), 'Event or Condition that could have prevented fulfillment of a Safety Function needed to Control the Release of Radioactive Material' and 10CFR50.72(b)(3)(v)(D), 'Event or Condition that could have prevented fulfillment of a Safety Function needed to Mitigate the Consequences of an Accident.' Unit 1 and Unit 2 were in Mode 1 and no movement of irradiated fuel, core alterations, or OPDRVs (Operations with the Potential to Drain the Reactor Vessel) were in progress in the secondary containment. An employee entered a secondary containment interlock and identified that both doors of the interlock opened simultaneously when the door on the reactor building side was opened. The employee immediately secured both doors in the interlock and notified the Main Control Room Supervisor. Both doors in the interlock were open for approximately 10 seconds. With both doors open, TS SR 3.6.4.1.2 was not met. This rendered secondary containment inoperable per TS 3.6.4.1. Reactor building differential pressure, as observed in the Main Control Room, has remained less than -0.25 inches of water column at all times. Initial investigation determined that the interlock for the doors was malfunctioning. Administrative controls (barricades and signs) have been put in place to ensure the doors remain closed pending repairs to the interlock. The licensee notified the NRC Resident Inspector. |