ENS Event | |
|---|---|
11:32 Nov 13, 2007 | |
| Title | Unusual Event Declared Due to Unexpected Reactor Vessel Water Level Change During a Refueling Outage with Irradiated Fuel in the Core |
| Event Description | 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 EAL classification of MU9 is no longer applicable.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. |
| Where | |
|---|---|
Crane  Pennsylvania (NRC Region 1) | |
| Reporting | |
| Emergency class: | Unusual Event |
| 10 CFR 50.72(a) (1) (i), Emergency Class Declaration | |
| Time - Person (Reporting Time:+-4.4 h-0.183 days <br />-0.0262 weeks <br />-0.00603 months <br />) | |
| Opened: | Boyd 07:08 Nov 13, 2007 |
| NRC Officer: | John Mackinnon |
| Last Updated: | Nov 13, 2007 |
| 43780 - NRC Website
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WEEKMONTHYEARENS 514552015-10-06T01:15:0006 October 2015 01:15:00
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