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http://dx.doi.org/10.1016/j.net.2019.02.016

Variability of plant risk due to variable operator allowable time for aggressive cooldown initiation  

Kim, Man Cheol (School of Energy Systems Engineering, Chung-Ang University)
Han, Sang Hoon (Integrated Safety Assessment Division, Korea Atomic Energy Research Institute)
Publication Information
Nuclear Engineering and Technology / v.51, no.5, 2019 , pp. 1307-1313 More about this Journal
Abstract
Recent analysis results with realistic assumptions provide the variability of operator allowable time for the initiation of aggressive cooldown under small break loss of coolant accident or steam generator tube rupture with total failure of high pressure safety injection. We investigated how plant risk may vary depending on the variability of operators' failure probability of timely initiation of aggressive cooldown. Using a probabilistic safety assessment model of a nuclear power plant, we showed that plant risks had a linear relation with the failure probability of aggressive cooldown and could be reduced by up to 10% as aggressive cooldown is more reliably performed. For individual accident management, we found that core damage potential could be gradually reduced by up to 40.49% and 63.84% after a small break loss of coolant accident or a steam generator tube rupture, respectively. Based on the importance of timely initiation of aggressive cooldown by main control room operators within the success criteria, implications for improvement of emergency operating procedures are discussed. We recommend conducting further detailed analyses of aggressive cooldown, commensurate with its importance in reducing risks in nuclear power plants.
Keywords
Probabilistic safety assessment; Plant risk; Core damage frequency; Aggressive cooldown; Rapid depressurization; Importance measures; Emergency operating procedures;
Citations & Related Records
Times Cited By KSCI : 2  (Citation Analysis)
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