Optimization method to branch-and-bound large SBO state spaces under dynamic probabilistic risk assessment via use of LENDIT scales and S2R2 sets

Nielsen, Jakob N.; Tokuhiro, Akira; Hiromoto, Robert E.; Khatry, Jivan

doi:10.1080/00223131.2014.917995

Cited by 9 publications

(3 citation statements)

References 9 publications

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“…DPRA models could use this method to perform supervised branching and generate scenarios, as the branchand-bound method carries out branching adaptively. Nielsen and Hakobyan [8,20] apply the branch-and-bound approach to DPRA, where a DDET for a station blackout transient is generated as in ADS. The branch-and-bound method defines which branches of the DDET are explored and pruned according to the upper and lower bounds and an objective function.…”

Section: State-space Pruningmentioning

confidence: 99%

Supervised dynamic probabilistic risk assessment: Review and comparison of methods

Maidana

Parhizkar²,

Gomola³

et al. 2023

Reliability Engineering & System Safety

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Section: State-space Pruningmentioning

confidence: 99%

Supervised dynamic probabilistic risk assessment: Review and comparison of methods

Maidana

Parhizkar²,

Gomola³

et al. 2023

Reliability Engineering & System Safety

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“…The core should be maintained in a safe condition after the following loss of the emergency AC power system in a duration, which is referred to as the coping time. A typical SBO event tree involving the mitigation measures is shown in Figure 1 [8]. From that figure, the decay core heat removal has to be maintained first by operation of the steam generator secondary side using the available DC power supply from the battery sets.…”

Section: Description Of Station Blackout Eventmentioning

confidence: 99%

Preliminary Assessment of Engineered Safety Features Against Station Blackout in Selected PWR Models

Ekariansyah

Widodo²,

Susyadi³

et al. 2021

Tri Dasa Mega

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The 2011 Fukushima accident did not prevent countries to construct new nuclear power plants (NPPs) as part of the electricity generation system. Based on the IAEA database, there are a total of 44 units of PWR type NPPs whose constructions are started after 2011. To assess the technology of engineered safety features (ESFs) of the newly constructed PWRs, a study has been conducted as described in this paper, especially in facing the station blackout (SBO) event. It is expected from this study that there are a number of PWR models that can be considered to be constructed in Indonesia from the year of 2020. The scope of the study is PWRs with a limited capacity from 900 to 1100 MWe constructed and operated after 2011 and small-modular type of reactors (SMRs) with the status of at least under licensing. Based on the ESFs design assessment, the passive core decay heat removal has been applied in the most PWR models, which is typically using steam condensing inside heat exchanger within a water tank or by air cooling. From the selected PWR models, the CPR-1000, HPR-1000, AP-1000, and VVER-1000, 1200, 1300 series have the capability to remove the core decay heat passively. The most innovative passive RHR of AP-1000 and the longest passive RHR time period using air cooling in several VVER models are preferred. From the selected SMR designs, the NuScale design and RITM-200 possess more advantages compared to the ACP-100, CAREM-25, and SMART. NuScale represents the model with full-power natural circulation and RITM-200 with forced circulation. NuScale has the longest time period for passive RHR as claimed by the vendor, however the design is still under licensing process. The RITM-200 reactor has a combination of passive air and water-cooling of the heat exchanger and is already under construction.

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“…PRHRS is actuated by fail-safe valves (they usually fail open) with a loss of power or signal, which helps to transfer heat to the coolant via HX. PRHRS can be catagorised into three types with distinct system configurations and use of length, energy, number, distribution, information and time (LENDIT) heuristic scales [50]: (a) NC via coupled RPV and HX immersed in coolant tank; (b) NC via coupled steam generators with HXs in coolant tank (e.g., SMART), and; (c) NC via coupled steam generators with HXs in reactor pool (e.g., NuScale) (Figure 2) [18]. Passive safety systems in iPWRs can be classified into four (4) types in terms of function: passive residual heat removal system (PRHRS), passive safety injection system (PSIS), passive depressurization system (PDS), and passive containment cooling system (PCCS).…”

Section: Passive Residual Heat Removal System (Prhrs)mentioning

confidence: 99%

Integral PWR-Type Small Modular Reactor Developmental Status, Design Characteristics and Passive Features: A Review

Zeliang

Tokuhiro

et al. 2020

Energies

Self Cite

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In recent years, the trend in small modular reactor (SMR) technology development has been towards the water-cooled integral pressurized water reactor (iPWR) type. The innovative and unique characteristics of iPWR-type SMRs provide an enhanced safety margin, and thus offer the potential to expand the use of safe, clean, and reliable nuclear energy to a broad range of energy applications. Currently in the world, there are about eleven (11) iPWR-type SMRs concepts and designs that are in various phases of development: under construction, licensed or in the licensing review process, the development phase, and conceptual design phase. Lack of national and/or internatonal comparative framework for safety in SMR design, as well as the proprietary nature of designs introduces non-uniformity and uncertainties in regulatory review. That said, the major primary reactor coolant system components, such as the steam generator (SG), pressurizer (PRZ), and control rod drive mechanism (CRDM) are integrated within the reactor pressure vessel (RPV) to inherently eliminate or minimize potential accident initiators, such as LB-loss of coolant accidents (LOCAs). This paper presents the design status, innovative features and characteristics of iPWR-type SMRs. We delineate the common technology trends, and highlight the key features of each design. These reactor concepts exploit natural physical laws such as gravity to achieve the safety functions with high level of margin and reliability. In fact, many SMR designs employ passive safety systems (PSS) to meet the evolving stringent regulatory requirements, and the extended consideration for severe accidents. A generic classification of PSS is provided. We constrain our discussion to the decay heat removal system, safety injection system, reactor depressurization system, and containment system. A review and comparative assessment of these passive features in each iPWR-type SMR design is considered, and we underline how it maybe more advantageous to employ passive systems in SMRs in contrast to conventional reactor designs.

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Optimization method to branch-and-bound large SBO state spaces under dynamic probabilistic risk assessment via use of LENDIT scales and S2R2 sets

Abstract: Optimization method to branch-and-bound large SBO state spaces under dynamic probabilistic risk assessment via use of LENDIT scales and S2R2 sets,

Cited by 9 publications

References 9 publications

Supervised dynamic probabilistic risk assessment: Review and comparison of methods

Supervised dynamic probabilistic risk assessment: Review and comparison of methods

Preliminary Assessment of Engineered Safety Features Against Station Blackout in Selected PWR Models

Integral PWR-Type Small Modular Reactor Developmental Status, Design Characteristics and Passive Features: A Review

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