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At 10:51 on 4/22/10, Susquehanna Unit 1 ex … At 10:51 on 4/22/10, Susquehanna Unit 1 experienced an automatic reactor SCRAM on reactor low level, +13", during the initial testing of the Feedwater Integrated Control System. Following the SCRAM, reactor water level dropped to approx. -30", and the Reactor Core Isolation Cooling system initiated and injected into the vessel. Level was recovered by the Feedwater System and the RCIC system. Division 2 Alternate Rod Insertion unexpectedly initiated during the level transient. Due to scheduled maintenance activities, the 11B Aux Bus did not transfer to the off site power supply post SCRAM. The 11B Aux bus was restored at 12:17. There were no ECCS initiations and no challenges to containment.</br>This event is a Reactor Protection System (RPS) actuation when the reactor is critical, and is reportable as a four hour ENS Notification under 10 CFR 50.72(b)(2)(iv)(B). This event is also an unplanned actuation of a system used to mitigate the consequences of a significant event and is reportable as an eight hour ENS notification under 10CFR50.72(b)(3)(iv)(A).</br>The scram was described as uncomplicated. All rods fully inserted and all systems functioned as required. The initiation of the alternative rod insertion should not occur unless level drops below -38" but the initiation did not result in any complications. The offsite supply breaker to Aux bus 11B was under maintenance when the scram occurred and so the loss of power was expected. This bus supplies some balance of plant loads which were lost (recirculation pump, condensate pump, and circulating water pump) but the loss of these components had no impact on the transient.</br>The NRC Resident Inspector has been notified. The licensee will notify State authorities and also plans a press release.uthorities and also plans a press release. +
14:51:00, 22 April 2010 +
13:20:00, 22 April 2010 +
14:51:00, 22 April 2010 +
At 10:51 on 4/22/10, Susquehanna Unit 1 ex … At 10:51 on 4/22/10, Susquehanna Unit 1 experienced an automatic reactor SCRAM on reactor low level, +13", during the initial testing of the Feedwater Integrated Control System. Following the SCRAM, reactor water level dropped to approx. -30", and the Reactor Core Isolation Cooling system initiated and injected into the vessel. Level was recovered by the Feedwater System and the RCIC system. Division 2 Alternate Rod Insertion unexpectedly initiated during the level transient. Due to scheduled maintenance activities, the 11B Aux Bus did not transfer to the off site power supply post SCRAM. The 11B Aux bus was restored at 12:17. There were no ECCS initiations and no challenges to containment.</br>This event is a Reactor Protection System (RPS) actuation when the reactor is critical, and is reportable as a four hour ENS Notification under 10 CFR 50.72(b)(2)(iv)(B). This event is also an unplanned actuation of a system used to mitigate the consequences of a significant event and is reportable as an eight hour ENS notification under 10CFR50.72(b)(3)(iv)(A).</br>The scram was described as uncomplicated. All rods fully inserted and all systems functioned as required. The initiation of the alternative rod insertion should not occur unless level drops below -38" but the initiation did not result in any complications. The offsite supply breaker to Aux bus 11B was under maintenance when the scram occurred and so the loss of power was expected. This bus supplies some balance of plant loads which were lost (recirculation pump, condensate pump, and circulating water pump) but the loss of these components had no impact on the transient.</br>The NRC Resident Inspector has been notified. The licensee will notify State authorities and also plans a press release.uthorities and also plans a press release. +
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32 +
Regarding Automatic Reactor Scrams Occur During Post-Modification Testing of the Digital Feedwater Integrated Control System +, 05000387/LER-2010-002, For Susquehanna Steam Electric Station, Regarding Automatic Reactor Scrams Occur During Post-Modification Testing of the Digital Feedwater Integrated Control System + and For Susquehanna Steam Electric Station +
00:00:00, 22 April 2010 +
Modification date"Modification date" is a predefined property that corresponds to the date of the last modification of a subject and is provided by <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Help:Special_properties">Semantic MediaWiki</a>.
02:09:50, 2 March 2018 +
13:20:00, 22 April 2010 +
true +
-0.0633 d (-1.52 hours, -0.00905 weeks, -0.00208 months) +
14:51:00, 22 April 2010 +
Reactor Scram on Low Reactor Vessel Water Level During Feedwater Integrated Control System Testing +
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