Comparison of human reliability analysis (HRA) results at the Forsmark nuclear power plant
Nordman, Antonia (2023)
2023
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Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:amk-2023060621754
https://urn.fi/URN:NBN:fi:amk-2023060621754
Tiivistelmä
The purpose of this thesis was to compare the human reliability analysis (HRA) results between the software HRA Calculator and the existing HRAs of the Forsmark nuclear power plant (NPP). The result of an HRA is given as a human error probability (HEP).
All eight cases examined are category C actions (post-initiator actions), which refer to the actions of plant personnel during an initiating event. Category C actions in general are separated into a cognitive part (diagnosis and decision-making), and an execution part (post-diagnosis action). For the purpose of this thesis, only the HEPs for the cognitive part were compared. Therefore, the value of HEP indicates the probability of failed diagnosis and decision-making.
In most cases examined, the higher HEP was received from the HRA method used by Forsmarks Kraftgrupp AB (FKA), which is called Enhanced Bayesian THERP. The results of three cases can be interpreted as similar for both the HRA Calculator and FKA’s method. The results of two cases differed significantly. In both cases the HEPs from FKA’s method were much higher than the HEPs from the HRA Calculator.
All eight cases examined are category C actions (post-initiator actions), which refer to the actions of plant personnel during an initiating event. Category C actions in general are separated into a cognitive part (diagnosis and decision-making), and an execution part (post-diagnosis action). For the purpose of this thesis, only the HEPs for the cognitive part were compared. Therefore, the value of HEP indicates the probability of failed diagnosis and decision-making.
In most cases examined, the higher HEP was received from the HRA method used by Forsmarks Kraftgrupp AB (FKA), which is called Enhanced Bayesian THERP. The results of three cases can be interpreted as similar for both the HRA Calculator and FKA’s method. The results of two cases differed significantly. In both cases the HEPs from FKA’s method were much higher than the HEPs from the HRA Calculator.