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On 7/11/01, at 2223 hours, the plant was o … On 7/11/01, at 2223 hours, the plant was operating at 100 percent reactor power when a loss of feedwater occurred resulting in an automatic reactor scram, an automatic trip of the Reactor Recirculation Pumps, an automatic initiation and injection of the High Pressure Core Spray System (HPCS) and the Reactor Core Isolation Cooling System (RCIC) and a Balance of Plant Isolation due to a valid Reactor Pressure Vessel (RPV) water low level signal. Subsequently, at 0400 on 7/12/01, an invalid low RPV water level signal occurred resulting in an invalid automatic initiation of the HPCS pump, HPCS diesel and associated support systems, however no injection occurred. All systems responses were as expected to the valid and to the invalid signals.</br></br>The cause of the loss of feedwater event was determined to be a blown fuse that supplies 24-Volt DC electrical power to the Loop B Analog Instrument Panel, which contains instrumentation for the feedwater control system. The cause of the invalid RPV low level actuation was determined to be due to a thermal hydraulic perturbation coincident with decreasing reactor pressure.</br></br>The power supply fuse was replaced and a thermographic examination was performed of all fuses located in the Control Room. A thermographic examination of the Control Room fuses was again performed following plant restoration at approximately 60 percent power. Although no additional failures were identified, fuses indicating above normal temperatures were replaced. To address the invalid HPCS initiation, the signal dampening for the HPCS RPV level instruments was increased in order to reduce the instrument vulnerability to short duration pulses.</br></br>This event is being reported in accordance with the requirements of 10CFR50.73(a)(2)(iv), an event or condition that resulted in specified system actuations.t resulted in specified system actuations. +
On 7/11/01, at 2223 hours, the plant was o … On 7/11/01, at 2223 hours, the plant was operating at 100 percent reactor power when a loss of feedwater occurred resulting in an automatic reactor scram, an automatic trip of the Reactor Recirculation Pumps, an automatic initiation and injection of the High Pressure Core Spray System (HPCS) and the Reactor Core Isolation Cooling System (RCIC) and a Balance of Plant Isolation due to a valid Reactor Pressure Vessel (RPV) water low level signal. Subsequently, at 0400 on 7/12/01, an invalid low RPV water level signal occurred resulting in an invalid automatic initiation of the HPCS pump, HPCS diesel and associated support systems, however no injection occurred. All systems responses were as expected to the valid and to the invalid signals.</br></br>The cause of the loss of feedwater event was determined to be a blown fuse that supplies 24-Volt DC electrical power to the Loop B Analog Instrument Panel, which contains instrumentation for the feedwater control system. The cause of the invalid RPV low level actuation was determined to be due to a thermal hydraulic perturbation coincident with decreasing reactor pressure.</br></br>The power supply fuse was replaced and a thermographic examination was performed of all fuses located in the Control Room. A thermographic examination of the Control Room fuses was again performed following plant restoration at approximately 60 percent power. Although no additional failures were identified, fuses indicating above normal temperatures were replaced. To address the invalid HPCS initiation, the signal dampening for the HPCS RPV level instruments was increased in order to reduce the instrument vulnerability to short duration pulses.</br></br>This event is being reported in accordance with the requirements of 10CFR50.73(a)(2)(iv), an event or condition that resulted in specified system actuations.t resulted in specified system actuations. +
Has query"Has query" is a predefined property that represents meta information (in form of a <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Subobject">subobject</a>) about individual queries and is provided by <a rel="nofollow" class="external text" href="https://www.semantic-mediawiki.org/wiki/Help:Special_properties">Semantic MediaWiki</a>.
0.0257 d (0.618 hours, 0.00368 weeks, 8.458515e-4 months) +, 0.0258 d (0.62 hours, 0.00369 weeks, 8.496565e-4 months) +, 1.157407e-5 d (2.777778e-4 hours, 1.653439e-6 weeks, 3.805e-7 months) +, 3.356481e-4 d (0.00806 hours, 4.794974e-5 weeks, 1.10345e-5 months) +, 0.0258 d (0.619 hours, 0.00368 weeks, 8.473735e-4 months) +, 0.0258 d (0.619 hours, 0.00369 weeks, 8.481345e-4 months) +, 0.00463 d (0.111 hours, 6.613757e-4 weeks, 1.522e-4 months) +, 0.00625 d (0.15 hours, 8.928571e-4 weeks, 2.0547e-4 months) + and 0.00133 d (0.0319 hours, 1.901455e-4 weeks, 4.37575e-5 months) +
3 +
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04:40:42, 1 December 2017 +
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