A Methodology for the Integration of Passive System Reliability With Success Criteria in a Probabilistic Framework for Advanced Reactors

Author(s):  
Acacia J. Brunett ◽  
Dave Grabaskas ◽  
Matthew Bucknor ◽  
Stefano Passerini

GE Hitachi Nuclear Energy (GEH) and Argonne National Laboratory are currently engaged in a joint effort to modernize and develop probabilistic risk assessment (PRA) techniques for advanced non-light water reactors. At a high level, the primary outcome of this project will be the development of next-generation PRA methodologies that will enable risk-informed prioritization of safety- and reliability-focused research and development, while also identifying gaps that may be resolved through additional research. A subset of this effort is the development of PRA methodologies that can be used for the determination of passive system reliability while integrating quantitative success criteria into the risk analysis framework. An updated passive system reliability approach has been developed for utilization in the PRISM PRA that systematically characterizes the impact of passive safety systems on key success criteria. This methodology is derived from the Reliability Method for Passive Systems (RMPS), but is refined to explicitly include consideration of overall mission success through satisfaction of success criteria, rather than only focusing on the passive system itself. This paper provides details on the integrated methodology, focusing on the interface between passive system reliability and success criteria. Specific examples for the passive systems/features of interest, RVACS and inherent reactivity feedback, are included. Additionally, aspects of the integrated passive system and success criteria methodology as they relate to the ASME/ANS Non-LWR PRA Standard are identified and discussed.

1999 ◽  
Vol 556 ◽  
Author(s):  
D. W. Esh ◽  
K. M. Goff ◽  
K. T. Hirsche ◽  
T. J. Battisti ◽  
M. F. Simpson ◽  
...  

AbstractA ceramic waste form is being developed by Argonne National Laboratory* (ANL) as part of the demonstration of the electrometallurgical treatment of spent nuclear fuel [1]. The halide, alkaline earth, alkali, transuranic, and rare earth fission products are stabilized in zeolite which is combined with glass and processed in a hot isostatic press (HIP) to form a ceramic composite. The mineral sodalite is formed in the HIP from the zeolite precursor. The process, from starting materials to final product, is relatively simple. An overview of the processing operations is given. The metrics that have been developed to measure the success or completion of processing operations are developed and discussed. The impact of variability in processing metrics on the durability of the final product is presented. The process is demonstrated to be robust for the type and range of operation metrics considered and the performance metric (PCT durability test) against which the operation metrics are evaluated.


Author(s):  
Dave Grabaskas ◽  
Acacia J. Brunett ◽  
Matthew Bucknor

GE Hitachi Nuclear Energy (GEH) and Argonne National Laboratory are currently engaged in a joint effort to modernize and develop probabilistic risk assessment (PRA) techniques for advanced non-light water reactors. At a high level, the primary outcome of this project will be the development of next-generation PRA methodologies that will enable risk-informed prioritization of safety- and reliability-focused research and development, while also identifying gaps that may be resolved through additional research. A subset of this effort is the development of PRA methodologies to conduct a mechanistic source term (MST) analysis for event sequences that could result in the release of radionuclides. The MST analysis seeks to realistically model and assess the transport, retention, and release of radionuclides from the reactor to the environment. The MST methods developed during this project seek to satisfy the requirements of the Mechanistic Source Term element of the ASME/ANS Non-LWR PRA standard. The MST methodology consists of separate analysis approaches for risk-significant and non-risk significant event sequences that may result in the release of radionuclides from the reactor. For risk-significant event sequences, the methodology focuses on a detailed assessment, using mechanistic models, of radionuclide release from the fuel, transport through and release from the primary system, transport in the containment, and finally release to the environment. The analysis approach for non-risk significant event sequences examines the possibility of large radionuclide releases due to events such as re-criticality or the complete loss of radionuclide barriers. This paper provides details on the MST methodology, including the interface between the MST analysis and other elements of the PRA, and provides a simplified example MST calculation for a sodium fast reactor.


Author(s):  
Oana Marin ◽  
Elia Merzari ◽  
Aleks Obabko ◽  
Andres Alvarez ◽  
Stephen Lomperski ◽  
...  

Thermal striping is of particular significance in nuclear reactor applications, primarily in sodium cooled fast reactors. The mixing chamber of the upper plenum of a nuclear reactor can be subjected to thermal striping unless designed such that the coolant is sufficiently mixed prior to reaching the top wall of the upper plenum. In order to conduct a systematic analysis of this phenomenon a simplified experimental set-up was designed and built at Argonne National Laboratory. In a parallel effort a similar simulation was conducted using the spectral-element code Nek5000. The set-up consists of two turbulent jets entering a rectangular tank via two hexagonal inlets, the interesting phenomena being the mixing within the tank. Two different inlet geometries were studied previously, both experimentally and via high-fidelity large-eddy simulations reporting various turbulent statistical quantities. To further assess the flow behavior we hereby perform a Proper Orthogonal Decomposition (POD) to identify the most dominant energetic modes and quantify their impact on the top wall of the upper plenum. The POD analysis of the experimental data in both inlet geometrical configurations is compared with LES and presented to highlight the impact of geometry on the velocity and thermal fields. We find a qualitative coherence between both simulation and experiment, characterized by a strong backflow in the weakly stable geometry, as indicated by the first mode, and the presence of three stagnation points in the strongly stable geometry setup. Also we identify a pairing of modes 1 and 3 with higher frequency than the second mode. This pairing is opposite in the two flow configurations leading to a faster decay of one of the jets in one case and a stable flow in the other.


Author(s):  
Dave Grabaskas ◽  
Acacia J. Brunett ◽  
Matthew Bucknor

GE Hitachi Nuclear Energy (GEH) and Argonne National Laboratory are currently engaged in a joint effort to modernize and develop probabilistic risk assessment (PRA) techniques for advanced non-light water reactors. At a high level the primary outcome of this project will be the development of next-generation PRA methodologies that will enable risk-informed prioritization of safety- and reliability-focused research and development, while also identifying gaps that may be resolved through additional research. A subset of this effort is the development of a reliability database (RDB) methodology to determine applicable reliability data for inclusion in the quantification of the PRA. The RDB method developed during this project seeks to satisfy the requirements of the Data Analysis element of the ASME/ANS Non-LWR PRA standard. The RDB methodology utilizes a relevancy test to examine reliability data and determine whether it is appropriate to include as part of the reliability database for the PRA. The relevancy test compares three component properties to establish the level of similarity to components examined as part of the PRA. These properties include the component function, the component failure modes, and the environment/boundary conditions of the component. The relevancy test is used to gauge the quality of data found in a variety of sources, such as advanced reactor-specific databases, non-advanced reactor nuclear databases, and non-nuclear databases. The RDB also establishes the integration of expert judgment or separate reliability analysis with past reliability data. This paper provides details on the RDB methodology, and includes an example application of the RDB methodology for determining the reliability of the intermediate heat exchanger of a sodium fast reactor. The example explores a variety of reliability data sources, and assesses their applicability for the PRA of interest through the use of the relevancy test.


2020 ◽  
Vol 10 (21) ◽  
pp. 7916
Author(s):  
Katarzyna Kubicka ◽  
Urszula Radoń

The objective of the article involves examining the impact of the type of supporting steel truss on its reliability under the conditions of a fire. The paper uses the system reliability method. Its application was preceded by the identification of kinematically admissible failure mechanisms (KAFMs) and the performance of strength-static calculations for all structural elements for a given moment of fire duration, meaning under the load of current temperature. The KAFMS were identified by the spectral analysis of the stiffness matrix. The criterion of the collapse for a single element was buckling for elements in compression and exceeding the yield strength for elements in tension. A reliability analysis and the calculation of temperature, axial forces, and the bearing capacity of individual elements were performed using original software created in the C++ language. The Cornell reliability index β was adopted as the measure of reliability. A drop in its value along with the fire development was presented for the analyzed structures. The obtained results indicate unambiguously that in the case of a structure subjected to fire action, the selection of a support method is of the utmost importance and determines its safety.


2008 ◽  
Vol 1124 ◽  
Author(s):  
Karl R Whittle ◽  
Mark Blackford ◽  
Gregory R Lumpkin ◽  
Katherine L Smith ◽  
Nestor J Zaluzec

AbstractGarnets, A3B2C3O12, are considered to be potential host phases for the immobilization of high-level nuclear waste as they can accommodate a number of elements of interest, including Zr, Ti and Fe. The naturally occurring garnet, kimzeyite, Ca3(Zr,Ti)2(Si,Al,Fe)3O12, can contain ˜30wt% Zr. An understanding of the radiation tolerance of these materials is crucial to their potential use in nuclear waste immobilization. In this study two synthetic analogues of kimzeyite of composition Ca3Zr2FeAlSiO12 and Ca3Hf2FeAlSiO12 were monitored in situ during irradiation with 1.0 MeV Kr ions using the intermediate voltage electron microscope-Tandem User Facility (IVEM) at Argonne National Laboratory. The structure of these materials was previously determined by neutron diffraction and 57Fe Mössbauer spectroscopy. Ca3Zr2FeAlSiO12 and Ca3Hf2FeAlSiO12 have very similar structural properties with cubic Ia3d symmetry, the only significant difference being the presence of Zr and Hf, respectively, on the 6 coordinated B sites.


2021 ◽  
Author(s):  
Marjan Meurisse ◽  
Adrien Lajot ◽  
Yves Dupont ◽  
Marie Lesenfants ◽  
Sofieke Klamer ◽  
...  

Abstract Background: With the spread of coronavirus disease 2019 (COVID-19), an existing national laboratory based surveillance system was adapted to daily monitor the epidemiological situation of SARS-CoV-2 in the Belgium by following the number of confirmed COVID-19 infections, the number of performed tests and the positivity ratio. We present these main indicators of the surveillance over a one-year period as well as the impact of the performance of the laboratories, regarding speed of processing the samples and reporting results, for surveillance.Methods: We describe the evolution of test capacity, testing strategy and the data collection methods during the first year of the epidemic in Belgium.Results: Between the 1th of March 2020 and the 28th of February 2021, 9,487,470 tests and 773,078 COVID-19 laboratory confirmed cases were reported. Two epidemic waves occurred, with a peak in April and October 2020. The capacity and performance of the laboratories improved continuously during 2020 resulting in a high level performance. Since the end of November 2020 90 to 95% of test results are reported at the latest the day after sampling was performed.Conclusions: Thanks to the effort of all laboratories a performant exhaustive national laboratory based surveillance system to monitor the epidemiological situation of SARS-CoV-2 was set up in Belgium in 2020. On top of expanding the number of laboratories performing diagnostics and significantly increasing the test capacity in Belgium, turnaround times between sampling and testing as well as reporting were optimized over the first year of this pandemic.


2021 ◽  
Vol 247 ◽  
pp. 10030
Author(s):  
A. G. Nelson ◽  
M. A. Smith ◽  
F. Heidet

The DIF3D code (DIFfusion 3D) has been a workhorse of fast reactor analysis work at Argonne National Laboratory for over 40 years. DIF3D was primarily built in the late 1970s as a three-dimensional multigroup diffusion equation solver operating on semi-structured grid geometries. In the mid-1990s, transport capabilities needed for high-leakage reactor configurations were added to DIF3D with the variational anisotropic nodal transport approach. Recent reactor design activities at Argonne are requiring that a thorough verification of the Argonne Reactor Computation (ARC) codes be performed. With DIF3D being central to the entire ARC system, the verification efforts are focused on the 3D Cartesian, 3D triangular, and 3D hexagonal core geometry options of DIF3D. Validation activities, while needed for the ongoing design activities at Argonne, are handled at a project-specific level. This paper summarizes the verification work so far on the forward and adjoint forms of the fixed source, inhomogeneous fixed source, and k-eigenvalue steady state transport and diffusion equations as implemented specifically for 3D triangular and hexagonal geometries in DIF3D. Since analytic solutions of the neutron diffusion and transport equations are either limited in scope or not possible, this verification required multiple tiers of problems unique to each solver and geometry type, each testing features independent and complementary arguments for why this separate testing of functionalities is acceptable. This separate testing was also supplemented with a high-level integral check of each the diffusion and transport capabilities and applicable geometries.


1997 ◽  
Vol 3 (S2) ◽  
pp. 773-774
Author(s):  
Katherine L. Smith ◽  
Nestor J. Zaluzec ◽  
Gregory R. Lumpkin

Zirconolite (CaZrTi2O7) is the major host phase for actinides in Synroc, a promising waste form for the immobilisation of high-level radioactive waste. The effect of radiation damage on the structure and durability of zirconolite are important to predictive modelling of zirconolite's behaviour in the repository environment and risk assessment.In this study, radiation damage effects in zirconolite were investigated by irradiating samples with 1.5 MeV Kr+ ions using the HVEM-Tandem at Argonne National Laboratory (ANL) and energy loss electron spectroscopy (EELS). The HVEM-Tandem consists of a modified AEI high votage transmission electron microscope interfaced to to a 2 MV tandem ion accelerator. EELS spectra were collected using a Philips 420 TEM, operated at 120 kV, fitted with a Gatan Model 607 Serial EELS. EELS data were recorded at resolutions of ˜1.0 eV and at a dispersion of about ˜0.25 eV.Selected area diffraction patterns (SADs) of individual grains of various zirconolites were monitored as a function of dose to establish the critical dose for aniorphisation (Dc).


2021 ◽  
Vol 79 (1) ◽  
Author(s):  
Marjan Meurisse ◽  
Adrien Lajot ◽  
Yves Dupont ◽  
Marie Lesenfants ◽  
Sofieke Klamer ◽  
...  

Abstract Background With the spread of coronavirus disease 2019 (COVID-19), an existing national laboratory-based surveillance system was adapted to daily monitor the epidemiological situation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in the Belgium by following the number of confirmed SARS-CoV-2 infections, the number of performed tests and the positivity ratio. We present these main indicators of the surveillance over a one-year period as well as the impact of the performance of the laboratories, regarding speed of processing the samples and reporting results, for surveillance. Methods We describe the evolution of test capacity, testing strategy and the data collection methods during the first year of the epidemic in Belgium. Results Between the 1st of March 2020 and the 28th of February 2021, 9,487,470 tests and 773,078 COVID-19 laboratory confirmed cases were reported. Two epidemic waves occurred, with a peak in April and October 2020. The capacity and performance of the laboratories improved continuously during 2020 resulting in a high level performance. Since the end of November 2020 90 to 95% of the test results are reported at the latest the day after sampling was performed. Conclusions Thanks to the effort of all laboratories a performant exhaustive national laboratory-based surveillance system to monitor the epidemiological situation of SARS-CoV-2 was set up in Belgium in 2020. On top of expanding the number of laboratories performing diagnostics and significantly increasing the test capacity in Belgium, turnaround times between sampling and testing as well as reporting were optimized over the first year of this pandemic.


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