Ranking Table Research Articles

Influence of cross-section uncertainties on the calculated results from a thermo-hydraulics code

This study deals with the influence of uncertainties in selected cross-section data in a neutronics code while their impact on the results from thermo-hydraulics code is investigated. Particular cross-section data were defined according to the Phenomenon Identification and Ranking Tables (PIRT) for a pressurized water reactor. Uncertainties were identified for the following data: β – delayed neutron fraction precursors and transport, absorption, ν-fission, κ-fission, down scattering for moderator temperature, moderator density and fuel temperature. As a neutronics code, PARCS in conjunction with thermo-hydraulics code TRACE was applied. Uncertainty analyses were carried out by the code DAKOTA where coupled PARCS/TRACE calculations were run 146 times in order to meet a two-sided 95/95 confidence interval. In the thermo-hydraulic code thermal power of the reactor core and inner temperature of the fuel rod were studied. This research shows that the most influential parameters associated with cross-section parametrization are moderator temperature and fuel temperature.

Optimization of sensitivity analysis in best estimate plus uncertainty and the application to large break LOCA of a three-loop pressurized water reactor

The best estimate plus uncertainty (BEPU) methodology is developed to carry out realistic safety analysis of the nuclear power plant. However, the sensitivity analysis in the conventional methodologies often leads to inaccurate results when lacking of the phenomenon identification and ranking table (PIRT) or adopting the local sensitivity analysis methods. As the initial inputs determined in short of the PIRT may neglect some important parameters or identify some unimportant parameters, and the local methods are not appropriate for complex and non-linear systems. In this study, an optimized moment-independent global sensitivity analysis method with very low computational cost was utilized to improve the sensitivity analysis framework of the BEPU methodology. The reliability as well as the applicability of the method were assessed through some tests and a large break loss of coolant accident (LBLOCA) of the LOFT facility. The improved sensitivity analysis framework was then applied to the BEPU analysis of a typical three-loop pressurized water reactor CPR1000, and the reliability of the optimized moment-independent method was further confirmed by comparing the sensitivity analysis result of the method to the results of the BEMUSE project and the Spearman method. Besides, two new parameters were identified to have great influence on the PCT, and the two parameters should be taken into consideration in the uncertainty analysis of the BEPU methodology.

Simulation and uncertainty analysis of main steam line break accident on an integral test facility

In order to investigate the performance of a Generation III BWR safety system, an Integral test facility was designed and conducted, and several integral tests were performed. The best estimate safety analysis of Main Steam Line Break (MSLB) accident using RELAP5/MOD3.3 and RELAP/SCDAPSIM/MOD3.4 (from now on referred as RELAP/SCDAP3.4) was performed. By comparing the simulation results with the test results, the prediction capability of the RELAP5/MOD3.3 and the RELAP/SCDAP3.4 was compared and analyzed. The RELAP/SCDAP3.4 code was selected to perform the uncertainty study. According to the Phenomenon Identification and Ranking Table, 12 input treatable parameters and 29 source code coefficients were selected with imposed uncertainty distribution to conduct uncertainty analysis. The 95/95 uncertainty band of the minimum core collapsed level were obtained and analyzed. In addition, the contribution weight of input treatable parameters and source code coefficients for the minimum core collapsed level were identified with the Spearman rank correlation coefficient.

A summary of fission-product-transport phenomena during SGTR severe accidents

A steam-generator-tube rupture (SGTR) in a pressurized-water reactor is a design-basis accident with which plants have been designed to cope. Its specific significance is in its potential to bypass the containment thereby providing a pathway for radioactivity release to the environment. In combination with significant core damage, uncontrolled SGTR may lead to accidental release of radioactivity in the form of aerosol particles and gaseous compounds.In this paper, we describe the phenomena identification and ranking tables (PIRT) prepared as an international collaboration for uncontrolled SGTR in connection with core damage. This PIRT is limited to fission-product transport and retention in the steam generator and release to the auxiliary building, i.e., the source term. The phenomena affecting the fission-product retention in the steam generator and release to the environment were divided into those relevant in a dry steam-generator secondary side, and those relevant in a flooded secondary side. Rankings were given to 17 phenomena in the dry and 16 phenomena in the flooded secondary side regarding their: i) impact on the source term, ii) the availability of experimental data applicable to SGTR severe-accident conditions, and iii) the availability of codes/models to describe the phenomenon under the conditions of SGTR severe accidents.The SGTR boundary conditions and the considered phenomena are briefly described. The results are given in the form of ranking tables separately for the dry and flooded steam generator secondary side. The most important phenomena and their interactions with other phenomena are discussed with references to existing data and models. The most important uncertain phenomena in the dry steam generator scenario are particle bounce and fragmentation; whereas inertial impaction and retention by droplets in the jet region are the most uncertain ones in the flooded configuration. The need for improved knowledge is, though, tempered by overall high aerosol retention in the latter scenario. The applicability of the existing data and models for SGTR accident analysis is considered in the discussion.

Traditional management of microorganisms in fermented beverages from cactus fruits in Mexico: an ethnobiological approach

BackgroundFermentation is an ancient technique for preserving and improving the qualities of food and beverages throughout the world. Microbial communities, not seen by the producers of fermented goods, are the actors involved in the fermentation process and are selected upon through different management processes in order to achieve a final product with culturally accepted features. This study documented the preparation of “colonche” which is a type of traditionally fermented beverages made with the fruits from several cactus species in two main producing regions of Mexico, the Altiplano and the Tehuacán Valley. We documented the selection processes of the cactus species used and the practices that could influence microbial community composition, as well as, how the producers reach the desirable sensorial attributes of the beverages.MethodsWe conducted 53 semi-structured interviews and participatory observations with colonche producers in 7 communities of the Altiplano and the Tehuacán Valley in order to characterize the practices and processes involved in the elaboration of the beverage. Opuntia and columnar cacti species used in colonche production were collected during fieldwork and identified. Selected sensorial attributes of Opuntia colonches were characterized by a ranking table and visualized by principal component analysis in order to distinguish differences of this beverage in the Altiplano localities.ResultsThirteen cactus species are used for colonche production in both regions studied. In the Altiplano, the most commonly used fruit is Opuntia streptacantha because it contributes to the preferred attributes of the beverage in this region. Selection of substrates by producers depends on their preference and the availability of fruits of O. streptacantha and other species. Fermentation is mainly conducted in clay pots which is perceived to be the best type of vessel contributing to the preferred sensorial properties of colonche. The two main differences in colonche preparation between the villages are the practice of boiling the fruit juice and the use of pulque (fermented sap of Agave species) as inoculum. The most contrasting sensorial attributes selected between localities are the alcohol content and sweetness, which might be in accordance with the practices used for obtaining the final product. Colonche is produced mainly for direct consumption and secondarily used as a commercialized good to be sold for economic gains contributing to the general subsistence of households. The preparation methods are passed on by close relatives, mainly women.ConclusionsTraditional producers of colonche use several techniques in order to reach specific sensorial attributes of the final product. The production of colonche has been upheld for generations but fermentation practices are divided into two categories; (1) the use of an inoculum (either from pulque, or from colonche saved from the previous year), and (2) the use of “spontaneous” fermentation. The differing practices documented reflect the contrasts in the preferred sensorial attributes between regions. Colonche is a beverage that contributes to regional pride, cultural identity and is appreciated because of its gastronomic value. Here, we argue that there is a clear relationship of human knowledge in the management of microbiota composition in order to produce this beverage. In-depth documentation of the microbiota composition and dynamics in colonche will contribute to the preservation of this valuable biocultural heritage.

„Tatarski czyn” Norwida między hierarchią a erupcją (semantyka, konteksty, konsekwencje)

Drawing on a scholarly polemic of the 1930s, this paper differentiates between two ways of understanding and translating Cyprian Norwid’s formula “tatarski czyn,” as ‘Tatar deed’ (from the Polish czyn) or as ‘Tatar rank’ (from the Russian chin according to the Tsarist Table of Ranks). The aim is to show how the eruptive versus the hierarchical readings of “tatarski czyn” have influenced the opinions on Norwid’s dialogic treatise Promethidion (1851) and, more generally, on his criticism of the utopian thought of Polish Romanticism and of Russian po-litics. It was Adam Mickiewicz who in the 1820s and 1830s pointed to the homonymy between czyn and chin and its potential in enacting ambivalences between the seemingly incommensurable imaginaries of eruption and hierarchy. Moreover, Mickiewicz already linked both understandings of czyn with a stereotypical Tatar, or Mongolian, “Asianness.” In this respect, Norwid’s formula is fairly conventional. What is genuinely original, however, is how Norwid turns Mickiewicz’s earlier ideas against those of the later Mickiewicz who, in his Paris Lectures on the Slavs (1840–1844), seems to glorify the “Tatar deed.” In contrast to the “bloody ladder” of Russian bureaucracy and the irrational tendency in Mickiewicz’s activism, Norwid suggests a “gradual labor” culminating in, not erupting with, the deed (Promethidion). This aspect of Norwid’s metaphorical thought is shown in a parallel reading with the philosopher August Cieszkowski who, in his Prolegomena to Historiosophy (1838), conceptualized history as a “texture of deeds” leading to institutions. Similarly, Norwid’s positive notion of the deed, i.e. his revision of Romantic activism, should be situated beyond the alternatives of eruption and hierarchy.

Not quite university people? Academics teaching on foundation studies programmes in New Zealand universities

ABSTRACT In the current neoliberal environment in higher education, universities are viewed as a valuable source of income. To generate this income, universities need to attract students, and in order to do so, they need to perform well in global ranking tables. These tables are influenced to a large extent by staff research and postgraduate teaching. Foundation studies programmes (FS) do not usually have a great deal to offer in these categories and this places staff teaching on these programmes in a difficult position. This article explores the perceptions of staff teaching on FS programmes in New Zealand universities, drawing on data from semi-structured interviews with 22 lecturers from four universities. Although lip service is paid in higher education circles to the importance of widening access to university education for traditionally marginalised groups, it appears that staff teaching on FS programmes do not, on the whole, receive acknowledgement, support or reward for the work that they do. Despite their marginalised status, these lecturers are committed to helping second chance learners. However, their ability to make a positive impact on these students’ lives is limited by their lowly status in the university sector. This article discusses the insights of FS staff and considers the implications of their positioning in the university sector. It offers some suggestions as to how, in a small way, universities could address the difficulties these academics face in their attempts to widen university access.

RESULTS OF A PHENOMENA IDENTIFICATION AND RANKING TABLE (PIRT) EXERCISE FOR A SEVERE ACCIDENT IN A SMALL MODULAR HIGH-TEMPERATURE GAS-COOLED REACTOR

Canada has attracted specific interest from developers of nonwater-cooled small modular reactor (SMR) technologies, including concepts based on high-temperature gas-cooled reactors (HTGRs). It is anticipated that some research and development (R&D) will be necessary to support safety analysis and licensing of these reactors in Canada. The Phenomena Identification and Ranking Table (PIRT) process is a formalized method in which a panel of experts identifies which physical phenomena are most relevant to the reactor safety analysis and how well understood these phenomena are. The PIRT process is thus a tool to assess current knowledge levels and (or) predictive capabilities of models, thus providing direction to a focused R&D program. This paper summarizes the results of a PIRT process performed by a panel of experts at Canadian Nuclear Laboratories for a limiting or “worst-case” accident scenario at a generic HTGR-type SMR. Suggestions are given regarding the highest priority R&D items to support severe accidents analysis of these reactors.

Development of phenomena identification and ranking tables (PIRTs) to implement research reactor-specific capability in SPACE code

The benefits of research reactor technology are always essentially accompanied by nuclear safety, which is ensured by a series of supporting analysis such as safety analysis. In order to extend the applicability of the Safety and Performance Analyzing Code (SPACE code) to safety analysis of typical open-tank-in-pool type research reactors using plate-type fuels, a Phenomena Identification and Ranking process was performed for most of the relevant internal event scenarios of a reference research reactor, i.e., the KiJang Research Reactor, designed and under development by the Korea Atomic Energy Research Institute (KAERI). The Structures, Systems, and Components (SSCs) important to nuclear safety of the reactor were included in the PIR processes. A summary of important results from the PIRT study on the research reactors is presented with a proposal on a preliminary set of data bases for a validation and verification matrix in addition to research issues.

Implementasi Metode Perbandingan Eksponensial (MPE) dalam Pendukung Keputusan Penilaian Kepala Madrasah Terbaik di Kota Mataram

The Madrasah Head who has good ability will give the best performance for the Madrasa he leads so that the Madrasa has good quality so that it can create a generation that is smart and has good character and good religion. One of the efforts of the Ministry of Religion of the Republic of Indonesia Mataram City Office to always maintain and improve the quality of Madrasah heads in the City of Mataram is to provide an assessment to choose the best Madrasah head so that all Madrasah heads in the City of Mataram have the motivation to always improve their quality. The design and manufacture of systems in this study use the waterfall methodology. This study uses the Exponential Comparison Method (MPE) which is one of the methods of the Decision Support System (SPK) used to determine the priority order of alternative decisions with multi criteria. The results of this assessment are to get the best Madrasah head ranking table in the city of Mataram based on the results of the system calculation, where these results can already be used by the Ministry of Religion of the Republic of Indonesia Mataram City Office as a consideration in determining the best Madrasa head in the city of Mataram. The conclusion of this study is the construction of a system that is able to produce the best level of Madrasah head assessment in the city of Mataram which can then be used to help the Ministry of Religion of the Republic of Indonesia Mataram City Office in making the decision to determine the best Madrasah head in the city of Mataram effectively and efficiently.

Academic Impact of Global Ranking of Higher Education Institutions in Kosovo

Globalization in higher education has highlighted the obligation to provide information on the level of academic quality provided by higher education institutions. This has resulted in the design of university ranking systems, respectively in creating of global and regional ranking tables. This information can and should be a contribution to the advancement of quality education in the country. Kosovar institutions that are competent in this field should show the courage to, in addition to providing information from international rankings, establish a credible national system for providing data, respectively the ranking list of higher education institutions in the country. This may help to identify important issues and information that will serve to create sustainable academic policies. This paper is exclusively based on empirical data provided by a questionnaire. As such it analyzes whether the ranking of higher education institutions in our country are needed and what will be the impact of academic quality measurements. These data enable the country's institutions to measure the public interest in the rate and dynamics of higher education development in the country, identifying the direction of university development. In these circumstances there should be no doubt about the obligation to provide this data, and only on the basis of it, the harmonization of public policies and legislation on quality in education and its role in the market.

Academic Impact of Global Ranking of Higher Education Institutions in Kosovo

Abstract Globalization in higher education has highlighted the obligation to provide information on the level of academic quality provided by higher education institutions. This has resulted in the design of university ranking systems, respectively in creating of global and regional ranking tables. This information can and should be a contribution to the advancement of quality education in the country. Kosovar institutions that are competent in this field should show the courage to, in addition to providing information from international rankings, establish a credible national system for providing data, respectively the ranking list of higher education institutions in the country. This may help to identify important issues and information that will serve to create sustainable academic policies. This paper is exclusively based on empirical data provided by a questionnaire. As such it analyzes whether the ranking of higher education institutions in our country are needed and what will be the impact of academic quality measurements. These data enable the country's institutions to measure the public interest in the rate and dynamics of higher education development in the country, identifying the direction of university development. In these circumstances there should be no doubt about the obligation to provide this data, and only on the basis of it, the harmonization of public policies and legislation on quality in education and its role in the market.

Assessment of swelling and constituent redistribution in uranium-zirconium fuel using phenomena identification and ranking tables (PIRT)

Metallic alloy U-Zr nuclear fuels remain a candidate for future US fast reactors. However, with more than 30 years of investigation into the system, U-Zr fuel remains unqualified and lacks predictive modeling capabilities. Phenomenon identification and ranking tables (PIRT) were developed for U-Zr fuels to prioritize the study of microstructural phenomena related to fuel performance and to aid predictive models. Two areas of emphasis, fuel swelling and constituent redistribution, were identified with PIRT and were evaluated in detail. The analysis identified influencing parameters that should be considered during future studies including: external mechanical constraint, temperature, composition, crystallographic texture, temperature gradient, fabrication constraints, fission density, fission rate, initial porosity, and pre-irradiation grain size. The PIRT results support the need for a comprehensive study that focus on the decoupling of fission rate, irradiation temperature, and alloy composition to independently investigate the microstructural evolution in the multiple phases typical of advanced reactor conditions.

Identification of important phenomena through the PIRT process for development of sodium fire analysis codes

JAEA has developed sodium fire analysis codes, SPHINCS and AQUA-SF, to evaluate the consequences of sodium fire events, which are a key issue in sodium-cooled fast reactor (SFR) plants. This paper describes a PIRT (Phenomena Identification and Ranking Table) process for such events. The present PIRT can be utilized to validate the sodium fire analysis codes. Because a sodium fire event in an SFR plant involves complex phenomena, various figures of merit (FOMs) for importance ranking could exist in the PIRT process. Therefore, the FOMs are specified through a factor analysis. Associated phenomena in a sodium fire event are identified through both element- and sequence-based phenomena analyses. The importance of each associated phenomenon is evaluated by considering the sequence-based analysis of associated phenomena related to the FOMs. Then, a ranking table for the event is established. An assessment matrix of important phenomena and experiments is completed. Sufficiency of experimental data is confirmed for the validation of models corresponding to the identified important phenomena in the sodium fire analysis codes. Additional assessments are discussed specifically for the aerosol module and the CFD module in three-dimensional codes from a perspective of careful validation.

Spatial-Temporal Person Re-Identification

Most of current person re-identification (ReID) methods neglect a spatial-temporal constraint. Given a query image, conventional methods compute the feature distances between the query image and all the gallery images and return a similarity ranked table. When the gallery database is very large in practice, these approaches fail to obtain a good performance due to appearance ambiguity across different camera views. In this paper, we propose a novel two-stream spatial-temporal person ReID (st-ReID) framework that mines both visual semantic information and spatial-temporal information. To this end, a joint similarity metric with Logistic Smoothing (LS) is introduced to integrate two kinds of heterogeneous information into a unified framework. To approximate a complex spatial-temporal probability distribution, we develop a fast Histogram-Parzen (HP) method. With the help of the spatial-temporal constraint, the st-ReID model eliminates lots of irrelevant images and thus narrows the gallery database. Without bells and whistles, our st-ReID method achieves rank-1 accuracy of 98.1% on Market-1501 and 94.4% on DukeMTMC-reID, improving from the baselines 91.2% and 83.8%, respectively, outperforming all previous state-of-theart methods by a large margin.

Comparison of Coastal Vulnerability Index applications for Barcelona Province

The Coastal Vulnerability Index (CVI) is one of the simplest and commonly used methods to assess coastal vulnerability to sea-level rise (SLR) driven erosion and/or inundation. In this way, it is a common tool contributing to the decision-making process in long-term coastal planning and management. However, there is not a unique approach to be adopted, and existing ones can supply different information and, thus, promote different decisions. Within this context, the main goal of this paper is to compare and evaluate different methodologies to determine CVI, and to suggest the most appropriate approach that can be generically applied for coastal vulnerability assessment. For doing this, the approaches proposed by Gornitz (1991), Shaw et al. (1998), Thieler and Hammar-Klose (2000), and Lopez et al. (2016) are applied along the 160 km long the Barcelona coastline in the Spanish Mediterranean.Shaw et al.‘s (1998) method appears to be the more realistic approach to assess vulnerability of the Barcelona coast while the overall vulnerability level calculated by the equation proposed by Gornitz (1991) indicate a wide variability, from highly vulnerable to a very low level of vulnerability. This study shows that the ranking tables generated from site-specific databases may not be applicable elsewhere, and indicates that it might be prudent to develop site or region-specific ranking categories to compute the overall CVI in order to provide reliable inputs to local coastal zone management initiatives. Despite the potential bias in the categorization of the overall CVI classes and their expert opinion/judgment approval requirements, CVI tools help decision makers to take the necessary actions to increase the resilience of coastal zones to SLR.

The primary morbidity of infectious and parasitic diseases in the structure of all diseases registered for the first time in life in the Russian Federation and the Northern Caucasian Federal okrug

In conditions of increased population migration, studying the situation on incidence of infectious and parasitogenic diseases is an actual problem. Particularly relevant is the analysis of newly detected incidence in the dynamics, which will allow to assess the well-being of the epidemiological situation in the region. Purpose of the study is to analyze the situation with incidence of some infectious and parasitogenic diseases and their share in the structure of other classes of diseases. The data from the Federal statistical monitoring in 2010-2017 were used related to the Russian Federation and the North Caucasus region. It is demonstrated that the incidence of diseases in the North Caucasus Federal District and the Stavropol region increased while it decreased at the National level. At that, there was a decreasing of incidence of some infectious and parasitogenic diseases both in the Russian Federation and in the North Caucasus Federal District with instability of indices in the Stavropol Krai. In the structure of primarily diagnosed diseases, infectious and parasitogenic diseases both in the the Russian Federation and in the North Caucasus Federal Okrug occupy the in the ranking table tenth point and sixth point in the Stavropol Krai. The results of the study demonstrated multi-directional trends in the dynamics of morbidity in the Russian Federation and the North Caucasus Federal Okrug. The decrease in the percentage of infectious and parasitogenic diseases testifies the improvement of epidemiological situation in overall.

Club convergence and drivers of digitalization across Indian states

Disparity in the level of digitalization is a crucial driver of economic inequality in an economy. Although a pocket of its population is still bereft of the benefits of digitalization, India currently has the second highest number of internet subscribers in the world despite the nation's late adoption of digital technology. An accurate assessment of the current state of digitalization in the country is required for devising effective initiatives towards building a Digital India and bridging the nation's internal digital divide. Considering 17 major Indian states and 21 variables for 10 years, we constructed a composite index of digitalization with the help of Principal Component Method (PCM). This paper identifies factors responsible for the digitalization divide across states. In the second part of the analysis, the study confirms, with the help of club convergence test, the absence of overall convergence towards digitalization and the existence of the non-convergent group. This paper also shows that the non-convergent group of states are at the bottom of the ranking table which indicates the need for greater attention to initiatives to bridge the digital divide.

Numerical study of the stratification erosion benchmark for NPPs containment using CFD code GASFLOW-MPI

During a severe accident involving a Nuclear Power Plant (NPP), a hydrogen-enriched stratification may occur in the dome of the containment. This is due to the gaseous density difference of a steam/hydrogen turbulent jet released from the break. This accident scenario is one of the high-ranking phenomena identified in the Phenomena Identification and Ranking Table (PIRT) for containment safety thermal hydraulics. In this work, the temporal evolution of the stratification erosion is analysed using the parallel CFD code GASFLOW-MPI with comparison to the experimental data from the THAI TH-20 benchmark, where helium is used as a hydrogen simulate. Identifying a suitable turbulence model is an important issue for a successful stratification erosion simulation due to turbulent mixing between the stratification and turbulent jet featured with the sharp velocity and density gradients. Three well-known turbulence models: 1. The classic k-ε model, 2. Large Eddy Simulation (LES) model and 3. Detached Eddy Simulation (DES) model are employed to evaluate their performances. Due to the negative buoyancy effect resulting from the light gas layer, the jet gradually loses its initial momentum and cannot penetrate the stratified layer in depth. The interaction Froude (Fr) number which is used to categorize the mixing mechanism is close to 1 in this work, indicating that the erosion process of the stratified layer is dominated by both the molecular diffusion and the momentum transport. The experimental data measured at different heights in THAI TH-20 benchmark, from the pure air region at the lower containment region up into the large helium concentration gradient region, and further up to high helium concentration region at the top of the containment. The calculated results show that the LES and DES turbulence models can capture time histories of helium concentration at all of the sensor points accurately, while the k-ε turbulence model predictions are always delayed due to its overestimating the turbulence mixing in the stratified layer. Moreover, compared with the k-ε model, more detailed turbulent eddy structure is resolved by the LES model and DES model, whose frequency satisfies the negative −5/3 energy decay rate for a wide region of frequency. Therefore, the LES and DES models are recommended for the stratification erosion simulation. This can provide guidance for nuclear engineers analysing hydrogen distribution phenomena during severe accidents.

Thermal-Hydraulic and Neutronic Phenomena Important in Modeling and Simulation of Liquid-Fuel Molten Salt Reactors

We discuss liquid-fuel molten salt (cooled) reactors (MSRs); how they will operate under normal, transient, and accident conditions; and the results of an expert elicitation to determine the corresponding thermal-hydraulic and neutronic phenomena important to understanding their behavior. Identifying these phenomena will enable the U.S. Nuclear Regulatory Commission (NRC), U.S. Department of Energy, and industry to develop or identify modeling functionalities and tools required to carry out confirmatory and licensing analyses that examine the validity and accuracy of an applicant’s calculations and help determine the margin of safety in plant design. The NRC frequently does an expert elicitation using a Phenomena Identification and Ranking Table (PIRT) to identify and evaluate the state of knowledge of important modeling phenomena. However, few details about the design of these reactors and the sequence of events during accidents are known, so the process used was considered a preliminary PIRT. A panel comprising a group of subject matter experts met to define phenomena that would need to be modeled and considered the impact/importance of each phenomenon with respect to specific figures of merit (FoMs) (e.g., salt temperature, velocity, and composition). Each FoM reflected a potential impact on radionuclide release or loss of a barrier to release. The panel considered what the path forward might be with respect to being able to model the phenomenon in a simulation code. Results are explained for both thermal and fast spectrum designs, with an emphasis on the thermal-hydraulic takeaways.It was concluded that compared to light water reactors, the lack of high-pressure operation, energetic break flow, depressurization, and quench front tracking may simplify some aspects of an MSR analysis. However, MSRs have new phenomena both for a license applicant and NRC confirmatory analysis. There is a need for enhanced understanding of physical properties for MSRs that encompass several individual thermophysical properties, including thermal conductivity, viscosity, specific heat, density, optical properties, thermodynamic properties, volatilities, solubilities, etc. Salt composition is closely linked to both these properties and the neutronics of the system. Additionally, the large number of MSR concepts and system designs means that there is wide variation in the potential modeling needs for these systems.