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| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 43780 | 13 November 2007 11:32:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Unusual Event Declared Due to Unexpected Reactor Vessel Water Level Change During a Refueling Outage with Irradiated Fuel in the Core | While in a drained down condition the reactor vessel experienced an unexplained loss of reactor coolant system inventory with irradiated fuel within the vessel. Licensee entered Emergency Action Level MU-9, Unusual Event at 0632 EST. Within a few minutes after entering EAL MU-9 reactor vessel water level returned to its initial water level of 13.7 inches above the centerline of the Hot Legs of the Reactor vessel. Licensee is investigating why reactor vessel water level changed. Chairman Klein's Comm. Assist. (Bill Orders), Comm. Jaczko's Assist (T. Hipschman), Comm. Lyons Assist (S. Baggett), R1DO (M. Miller), R2DO (M. Lesser), R3DO (M. Phillips), R4DO (V. Campbell) , DHS (A. Ackers), FEMA (Sullivan), DOE (S. Bailey), USDA (Watts), HHS (C. Harper) , EPA (NRC) Chief Brown were notified.
Termination of Unusual Event. EAL classification of MU9 is no longer applicable. Investigation of the unplanned Reactor vessel level showed no indication of leakage into any building containing RCS piping. The apparent cause of the event is due to a slight negative pressure in the RCS. When the OTSG lower manways were installed with HEPA filters fan units running, the indicated RCS level lowered and stabilized due to the HEPA units drawing air from the RCS. No actual RCS inventory loss occurred. When the HEPA units were turned off the RCS level returned to the indicated Reactor vessel level prior to the event. In accordance with station procedures this EAL event was terminated at 0929 on 11/13/07. The licensee notified the Resident Inspector, State and Local Officials of this event update R1DO (D. Holody), NRR EO (J. Dozier), IRD (B. McDermott) , DHS ASWO (Ed Hoisinton) and FEMA (D. Sullivan) were notified of the termination of the Unusual Event. | Reactor Coolant System | |
| ENS 47190 | 23 August 2011 18:01:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Notification of an Unusual Event Due to a Seismic Event | At 1401 hrs. EDT on 8/23/11, TMI (Three Mile Island) declared an Unusual Event due to a threshold seismic condition (HU5) earthquake. The earthquake was felt at the plant. No equipment damage has been identified. No personnel injuries were reported. The licensee has notified the NRC Resident Inspector and state and local authorities.
The Unusual Event declared at 1401 EDT due to the ground motion felt at the site has been terminated at 1730 EDT. Walkdowns have been performed and no equipment damage has been identified. The plant remains in a stable condition at 100% power. Offsite power and diesel generators were verified to be unaffected by the event. The licensee has notified the NRC Resident Inspector and state and local authorities. Notified R1 IRC (Dentil), IRD (Gott), DHS (Bean), FEMA (Via), USDA (Kraus), and DOE (Turner). | ||
| ENS 51455 | 6 October 2015 01:15:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Alert Declaration Due to Fire in the Auxiliary Building | At 2115 (EDT) on 10/05/15, an Alert was declared due to a fire in the Auxiliary building affecting DC-P-1A (Decay closed cooling pump 1A) and A-Train safety equipment. The fire is out. The licensee reported the fire was extinguished at approximately 2201 EDT. The fire did not hamper operations personnel responding to the fire. Offsite fire assistance was requested. The NRC Resident Inspector will be notified. The licensee notified the York Haven Power Station, PEMA (Pennsylvania Emergency Management Agency), and the counties of Cumberland, Lebanon, Lancaster, York, and Dauphin. Notified DHS, FEMA, USDA, HHS, DOE, DHS NICC, EPA EOC, FEMA NWC (via email), FDA EOC (via email) and Nuclear SSA (via email).
The licensee is terminating the Alert at 0009 EDT on 10/06/15 based on the following: At 2115 (EDT) on 10/05/15, an Alert (HA3) was declared due to a fire in the Decay Closed Cooling Water Pump '1A' motor and breaker. The fire was extinguished at 2201 (EDT). Following inspection by electrical maintenance the 'P' 480V bus was re-energized at 2305 (EDT) and restoration of previously running loads is in progress. Station (TMI) is in a 72-hour LCO for repairs to the Decay Closed Cooling Water Pump '1A' (DC-P-1A). TMI (Three Mile Island) is terminating the event based upon the above information. The licensee notified the York Haven Power Station, PEMA (Pennsylvania Emergency Management Agency), and the counties of Cumberland, Lebanon, Lancaster, York, and Dauphin. The licensee will issue a press release. The licensee informed the NRC Resident Inspector. Notified R1DO (Bickett), NRR (Howe) and IRD (Gott). Notified DHS, FEMA, USDA, HHS, DOE, DHS NICC, EPA EOC, FEMA NWC (via email), FDA EOC (via email) and Nuclear SSA (via email). |