ENS 40695

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v t e ENS Event
20:35 Apr 21, 2004
Title	Manual Reactor Scram in Response to High Main Turbine Vibration During Startup
Event Description	At 1635 on 04/21/2004, Susquehanna Unit 1 was returning to service from its 13th Refueling and Inspection Outage which included main turbine replacement. During start-up turbine testing with the generator off line, several main turbine bearings experienced high vibration. In response to these high vibrations, the reactor was manually scrammed from approximately 17% power. The main steam line isolation valves were manually closed and main condenser vacuum was broken in order to more rapidly slow the main turbine speed. All control rods fully inserted on the SCRAM, a level 3 containment isolation signal was received as expected. RCIC was manually initiated to control reactor water level. Lowest reactor water level reached was approximately 3" narrow range. There were no radioactive releases. This RPS actuation is reportable under 10CFR50.72(b)(2)(iv)(B) as an 'Unplanned RPS Actuation with the Reactor Critical.' The RPS Actuation and the RCIC injection are reportable per 10CFR50.72(b)(3)(iv)(A) 'Unplanned Actuations of Systems that Mitigate the Consequences of Significant Events.' Investigation into the high main turbine bearing vibrations is ongoing. The main turbine was tripped prior to the manual scram and no SRVs have lifted due to low decay heat level. The electric plant is in a normal lineup. The licensee notified the NRC Resident Inspector and the PEMA representative.

ENS 40695 +/-
Where
Susquehanna Pennsylvania (NRC Region 1)
Reporting

10 CFR 50.72(b)(2)(iv)(B), RPS Actuation 10 CFR 50.72(b)(3)(iv)(A), System Actuation
Time - Person (Reporting Time:+-2.48 h-0.103 days <br />-0.0148 weeks <br />-0.0034 months <br />)
Opened:	Gordon Robinson 18:06 Apr 21, 2004
NRC Officer:	Jeff Rotton
Last Updated:	Apr 21, 2004
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v • d • e

v t e Emergency Notification System
Susquehanna with 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation, 10 CFR 50.72(b)(3)(iv)(A), System Actuation
WEEKMONTHYEAR2023-03-23T21:36:00 [Table view]
[ENS list for Susquehanna]

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