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Title:	Human reliability analysis in probabilistic safety assessment during the operation of PUSPATI Research Reactor
Authors:	Ahmad Hassan Sallehudin Mohd Sarif (P70044)
Supervisor:	Faizal Mohammed, Prof. Dr.
Keywords:	Human reliability Probabilistic Safety Assessment Nuclear research reactor PUSPATI Universiti Kebangsaan Malaysia -- Dissertations
Issue Date:	3-Mar-2017
Description:	Probabilistic Safety Assessment (PSA) is an important tool in the assessment of a Nuclear Power Plant (NPP) safety. It is used in the regulatory process and in various risk-informed applications of the NPP. These importances of PSA approach are however not much involved in the safety assessment of a nuclear research reactor (NRR). The risk perceived for the NRR is considerably lower compared to the NPP. On the other hand, human actions (HAs) are crucial to the operation of a NRR in view of the fact that the operation of a NRR involves research activities with various kinds of human interventions and modes of operations. Moreover, during the abnormal condition, safety mitigation systems usually have to be performed manually by human operators. Therefore, there is a crucial need to systematically assess the effects and contributions of human error (HE) to the safety risk at a NRR and subsequently provide the possible back-fitting measures. The scope of this study comprises of the performance of Human Reliability Analysis (HRA) methodological framework which is adapted from the HRA methodology for the commercial NPP PSA. This framework is conducted in conjunction with the development of a Level 1 PSA as defined by the International Atomic Energy Agency (IAEA) for the open pool type PUSPATI TRIGA reactor (PTR) operated by the Malaysian Nuclear Agency. The comprehensive analysis processes involved in this study are: identification of HAs, screening of HAs, quantification of human error probabilities (HEPs), and representation of human failure events in the developed logic models. Subsequently, human contribution to the safety risk is quantitatively evaluated by quantifying the important measures of the human failure events. Results from this study demonstrated that following to the screening phase, two HAs for the significant reactor systems during accident condition has been derived. Meanwhile, a HA which contributes to an accident initiation has been found. The HEPs for these two types of HAs are quantified using the Technique for Human Error Rate Prediction (THERP). A number of HAs specifically in response to the eight initiating events are identified and their HEP are quantified by means of Standardized Plant Analysis Risk-Human Reliability Analysis (SPAR-H) method. The cognitive aspect of the operators in response to the initiating events is analyzed through the development of an operator decision tree. All the three types of HAs and their corresponding HEPs are subsequently incorporated into the PSA fault trees and event trees for the generation of minimal cut sets. As a result, two risk measures defined as fuel degradation and fuel degradation due to exposure to the air, HA attributes have contributed 98% and 78%, respectively. The quantitative results further indicate that, HAs in response to the initiating events are the dominant risk contributor. In case of fuel degradation, results from this study indicate that if Procedure-Performance Shaping Factor for the associated HAs specifically in response to initiating events is postulated at the nominal level, the risk would be reduced by 77%. Contributions of other type of HAs are minimal because majority of them are not applicable to the current scope of PSA and thus are screened out. It is hypothesized from this study that HAs at the NRR considerably contributing to the overall defined risk. The implemented HRA framework has been systematically identified, quantified and modeled significant HEs and the corresponding potential back-fitting measures to increase operators' performance. Therefore, the overall safety risk at the (PTR) can be significantly reduced.,Certification of Master's/Doctoral Thesis" is not available
Pages:	211
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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