TEPCO

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2Probabilistic risk assessments
3Selecting accident sequences
4567Effectiveness assessments Major accident response facilities（response to major accidents） (Reactor core damage prevention measures, Primary containment vessel damage prevention measures,
Fuel damage prevention measures in the spent fuel storage pools, Fuel damage prevention measures during reactor shutdowns) 8Analysis codes

Requirements from the New Regulatory Requirements
●Assessments should be conducted to confirm that major accident countermeasures can prevent damage to reactor cores or primary containment vessels.
Actions taken at the Kashiwazaki-Kariwa Nuclear Power Station
●The step sequences to reach a major accident without measures in place and the probability of its occurrence were assessed.
●The step sequences were categorized based on the characteristics of how they progress,
　and several step sequences were selected to represent each category.
●It was assessed that damage to reactor cores or primary containment vessels can be prevented if measures are implemented to counter
　the selected sequences of a major accident.
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TEPCO

Back to the list

2Probabilistic
risk assessments
3Selecting accident
sequences
4Effectiveness
assessments
(Reactor core damage prevention measures) 5Effectiveness
assessments
(Primary containment vessel
damage prevention measures) 6Effectiveness
assessments
(Fuel damage prevention measures
in the spent fuel storage pools) 7Effectiveness
assessments
(Fuel damage prevention measures
during reactor shutdowns) 8Analysis codes Major accident response facilities （response to major accidents）

Requirements from the New Regulatory Requirements
●Assessments should be conducted to confirm that major accident countermeasures can prevent damage to reactor cores or primary containment vessels.
Actions taken at the Kashiwazaki-Kariwa Nuclear Power Station
●The step sequences to reach a major accident without measures in place and the probability of its occurrence were assessed.
●The step sequences were categorized based on the characteristics of how they progress,and several step sequences were selected to represent each category.
●It was assessed that damage to reactor cores or primary containment vessels can be prevented if measures are implemented to counter the selected sequences of a major accident.
Back to the list