Finite mixture models for sensitivity analysis of thermal hydraulic codes for passive safety systems analysis

The key purpose of this paper is to present an alternative viewpoint for combining expert opinions based on finite mixture models. Moreover, we consider that the components of the mixture are not necessarily assumed to be from the same parametric family. This approach can enable the agent to make informed decisions about the uncertain quantity of interest in a flexible manner that accounts for multiple sources of heterogeneity involved in the opinions expressed by the experts in terms of the parametric family, the parameters of each component density, and also the mixing weights. Finally, the proposed models are employed for numerically computing quantile-based risk measures in a collective decision-making context.

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iB1350: A Generation III.7 Reactor After the Fukushima Daiichi Accident

Volume 2: Smart Grids, Grid Stability, and Offsite and Emergency Power; Advanced and Next Generation Reactors, Fusion Technology; Safety, Security, and Cyber Security; Codes, Standards, Conformity Assessment, Licensing, and Regulatory Issues ◽

10.1115/icone24-60523 ◽

2016 ◽

Author(s):

Takashi Sato ◽

Keiji Matsumoto ◽

Kenji Hosomi ◽

Keisuke Taguchi

Keyword(s):

Cooling System ◽

Boiling Water ◽

Passive Safety ◽

Active Safety ◽

Water Reactor ◽

Airplane Crash ◽

Passive Safety Systems ◽

Active Safety Systems ◽

Fukushima Daiichi ◽

Safety Systems

iB1350 stands for an innovative, intelligent and inexpensive boiling water reactor 1350. It is the first Generation III.7 reactor after the Fukushima Daiichi accident. It has incorporated lessons learned from the Fukushima Daiichi accident and Western European Nuclear Regulation Association safety objectives. It has innovative safety to cope with devastating natural disasters including a giant earthquake, a large tsunami and a monster hurricane. The iB1350 can survive passively such devastation and a very prolonged station blackout without any support from the outside of a site up to 7 days even preventing core melt. It, however, is based on the well-established proven Advance Boiling Water Reactor (ABWR) design. The nuclear steam supply system is exactly the same as that of the current ABWR. As for safety design it has a double cylinder reinforced concrete containment vessel (Mark W containment) and an in-depth hybrid safety system (IDHS). The Mark W containment has double fission product confinement barriers and the in-containment filtered venting system (IFVS) that enable passively no emergency evacuation outside the immediate vicinity of the plant for a severe accident (SA). It has a large volume to hold hydrogen, a core catcher, a passive flooding system and an innovative passive containment cooling system (iPCCS) establishing passively practical elimination of containment failure even in a long term. The IDHS consists of 4 division active safety systems for a design basis accident, 2 division active safety systems for a SA and built-in passive safety systems (BiPSS) consisting of an isolation condenser (IC) and the iPCCS for a SA. The IC/PCCS pools have enough capacity for 7-day grace period. The IC/PCCS heat exchangers, core and spent fuel pool are enclosed inside the containment vessel (CV) building and protected against a large airplane crash. The iB1350 can survive a large airplane crash only by the CV building and the built-in passive safety systems therein. The dome of the CV building consists of a single wall made of steel and concrete composite. This single dome structure facilitates a short-term construction period and cost saving. The CV diameter is smaller than that of most PWR resulting in a smaller R/B. Each active safety division includes only one emergency core cooling system (ECCS) pump and one emergency diesel generator (EDG). Therefore, a single failure of the EDG never causes multiple failures of ECCS pumps in a safety division. The iB1350 is based on the proven ABWR technology and ready for construction. No new technology is incorporated but design concept and philosophy are initiative and innovative.

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Unsupervised learning of finite mixture models using mean field games

2011 49th Annual Allerton Conference on Communication, Control, and Computing (Allerton) ◽

10.1109/allerton.2011.6120185 ◽

2011 ◽

Cited By ~ 3

Author(s):

Sergio Pequito ◽

A. Pedro Aguiar ◽

Bruno Sinopoli ◽

Diogo A. Gomes

Keyword(s):

Unsupervised Learning ◽

Mixture Models ◽

Finite Mixture Models ◽

Mean Field ◽

Finite Mixture ◽

Mean Field Games

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Non-local spatially varying finite mixture models for image segmentation

Statistics and Computing ◽

10.1007/s11222-020-09988-w ◽

2021 ◽

Vol 31 (1) ◽

Author(s):

Javier Juan-Albarracín ◽

Elies Fuster-Garcia ◽

Alfons Juan ◽

Juan M. García-Gómez

Keyword(s):

Image Segmentation ◽

Mixture Models ◽

Finite Mixture Models ◽

Finite Mixture ◽

Non Local ◽

Spatially Varying

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Investigation of effects of nonavailability of passive safety systems on the reactor behaviour during LOCA Scenario in AP600

Kerntechnik ◽

10.1515/kern-2020-0080 ◽

2021 ◽

Vol 86 (3) ◽

pp. 244-255

Author(s):

S. H. Abdel-Latif ◽

A. M. Refaey

Keyword(s):

Passive Safety ◽

Primary System ◽

Water Storage Tank ◽

The Core ◽

Passive Safety Systems ◽

Loss Of Coolant Accident ◽

Passive Safety System ◽

Stage 4 ◽

Core Cooling ◽

Safety Systems

Abstract The AP600 is a Westinghouse Advanced Passive PWR with a two–loop 1 940 MWt. This reactor is equipped with advanced passive safety systems which are designed to operate automatically at desired set-points. On the other hand, the failure or nonavailability to operate of any of the passive safety systems may affect reactor safety. In this study, modeling and nodalization of primary and secondary loops, and all passive reactor cooling systems are conducted and a 10-inch cold leg break LOCA is analyzed using ATHLET 3.1A Code. During loss of coolant accident in which the passive safety system failure or nonavailability are considered, four different scenarios are assumed. Scenario 1 with the availability of all passive systems, scenario 2 is failure of one of the accumulators to activate, scenario 3 is without actuation of the automatic depressurization system (ADS) stages 1–3, and scenario 4 is without actuation of ADS stage 4. Results indicated that the actuation of passive safety systems provide sufficient core cooling and thus could mitigate the accidental consequence of LOCAs. Failure of one accumulator during LOCA causes early actuation of ADS and In-Containment Refueling Water Storage Tank (IRWST). In scenario 3 where the LOCA without ADS stages 1–3 actuations, the depressurization of the primary system is relatively slow and the level of the core coolant drops much earlier than IRWST actuation. In scenario 4 where the accident without ADS stage-4 activation, results in slow depressurization and the level of the core coolant drops earlier than IRWST injection. During the accident process, the core uncovery and fuel heat up did not happen and as a result the safety of AP600 during a 10-in. cold leg MBLOCA was established. The relation between the cladding surface temperature and the primary pressure with the actuation signals of the passive safety systems are compared with that of RELAP5/Mode 3.4 code and a tolerable agreement was obtained.

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