The development of the AP-1000 design and of its precursor AP-600 started in the aftermath of the Chernobyl event (1986) when, among the other things, the need came out from scientific and technological community for a system resilient to deliberate threats by humans. Then, the ‘passive-system’ design-concept became relevant. The first AP-1000 entered in operation around three decades after that event. The issue in this paper is how much the progress in nuclear science and technology, since the end of 1980’s, affected the design of AP-1000. Five interconnected areas are identified, or (a) reliability of passive systems; (b) scaling and uncertainty; (c) coupling between three-dimensional neutron physics and thermal hydraulics; (d) consideration of large break loss of coolant; (e) simulation of instrumentation and control systems. All the areas are relevant for AP-1000 and standard Pressurized Water Reactors (PWR); however, the areas (a) and (b) have specific applicability for AP-1000 and constitute the main concern for the paper. The conclusion from qualitative investigation is that safety demonstration did not take full benefits from progress in those areas: inadequacies characterize the scaling database and processes for determining the reliability of thermal hydraulic passive systems did not receive proper attention.
Validation, Uncertainty, Scaling, Passive Systems: AP-1000 Challenges
D'Auria Francesco
Primo
Conceptualization
2022-01-01
Abstract
The development of the AP-1000 design and of its precursor AP-600 started in the aftermath of the Chernobyl event (1986) when, among the other things, the need came out from scientific and technological community for a system resilient to deliberate threats by humans. Then, the ‘passive-system’ design-concept became relevant. The first AP-1000 entered in operation around three decades after that event. The issue in this paper is how much the progress in nuclear science and technology, since the end of 1980’s, affected the design of AP-1000. Five interconnected areas are identified, or (a) reliability of passive systems; (b) scaling and uncertainty; (c) coupling between three-dimensional neutron physics and thermal hydraulics; (d) consideration of large break loss of coolant; (e) simulation of instrumentation and control systems. All the areas are relevant for AP-1000 and standard Pressurized Water Reactors (PWR); however, the areas (a) and (b) have specific applicability for AP-1000 and constitute the main concern for the paper. The conclusion from qualitative investigation is that safety demonstration did not take full benefits from progress in those areas: inadequacies characterize the scaling database and processes for determining the reliability of thermal hydraulic passive systems did not receive proper attention.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
