TY - JOUR
T1 - Evaluation of risk impact of changes to Completion Times addressing model and parameter uncertainties
AU - Martorell, S.
AU - Martón, I.
AU - Villamizar, M.
AU - Sánchez, A. I.
AU - Carlos, S.
N1 - Funding Information:
Authors are grateful to the Spanish Ministry of Science and Innovation for the financial support of this work (Research Project ENE2010-17449 and ENE2013-45540-R ).
PY - 2014/10
Y1 - 2014/10
N2 - This paper presents an approach and an example of application for the evaluation of risk impact of changes to Completion Times within the License Basis of a Nuclear Power Plant based on the use of the Probabilistic Risk Assessment addressing identification, treatment and analysis of uncertainties in an integrated manner. It allows full development of a three tired approach (Tier 1-3) following the principles of the risk-informed decision-making accounting for uncertainties as proposed by many regulators. Completion Time is the maximum outage time a safety related equipment is allowed to be down, e.g. for corrective maintenance, which is established within the Limiting Conditions for Operation included into Technical Specifications for operation of a Nuclear Power Plant. The case study focuses on a Completion Time change of the Accumulators System of a Nuclear Power Plant using a level 1 PRA. It focuses on several sources of model and parameter uncertainties. The results obtained show the risk impact of the proposed CT change including both types of epistemic uncertainties is small as compared with current safety goals of concern to Tier 1. However, what concerns to Tier 2 and 3, the results obtained show how the use of some traditional and uncertainty importance measures helps in identifying high risky configurations that should be avoided in NPP technical specifications no matter the duration of CT (Tier 2), and other configurations that could take part of a configuration risk management program (Tier 3).
AB - This paper presents an approach and an example of application for the evaluation of risk impact of changes to Completion Times within the License Basis of a Nuclear Power Plant based on the use of the Probabilistic Risk Assessment addressing identification, treatment and analysis of uncertainties in an integrated manner. It allows full development of a three tired approach (Tier 1-3) following the principles of the risk-informed decision-making accounting for uncertainties as proposed by many regulators. Completion Time is the maximum outage time a safety related equipment is allowed to be down, e.g. for corrective maintenance, which is established within the Limiting Conditions for Operation included into Technical Specifications for operation of a Nuclear Power Plant. The case study focuses on a Completion Time change of the Accumulators System of a Nuclear Power Plant using a level 1 PRA. It focuses on several sources of model and parameter uncertainties. The results obtained show the risk impact of the proposed CT change including both types of epistemic uncertainties is small as compared with current safety goals of concern to Tier 1. However, what concerns to Tier 2 and 3, the results obtained show how the use of some traditional and uncertainty importance measures helps in identifying high risky configurations that should be avoided in NPP technical specifications no matter the duration of CT (Tier 2), and other configurations that could take part of a configuration risk management program (Tier 3).
KW - Allowed outage times
KW - Completion Times
KW - Decision-making
KW - Probabilistic Risk Assessment
KW - Risk-informed
KW - Technical Specifications
KW - Uncertainty
UR - http://www.scopus.com/inward/record.url?scp=84903614102&partnerID=8YFLogxK
U2 - 10.1016/j.ress.2014.06.003
DO - 10.1016/j.ress.2014.06.003
M3 - Artículo en revista científica indexada
AN - SCOPUS:84903614102
SN - 0951-8320
VL - 130
SP - 190
EP - 201
JO - Reliability Engineering and System Safety
JF - Reliability Engineering and System Safety
ER -