Main Results of Phase IV BEMUSE Project: Simulation of LBLOCA in an NPP

Phase IV of BEMUSE Program is a necessary step for a subsequent uncertainty analysis. It includes the simulation of the reference scenario and a sensitivity study. The scenario is a LBLOCA and the reference plant is Zion 1 NPP, a 4 loop PWR unit. Thirteen participants coming from ten different countries have taken part in the exercise. The BEMUSE (Best Estimate Methods plus Uncertainty and Sensitivity Evaluation) Programhas been promoted by theWorking Group on AccidentManagement and Analysis (WGAMA) and endorsed by the Committee on the Safety of Nuclear Installations (CSNI). The paper presents the results of the calculations performed by participants and emphasizes its usefulness for future uncertainty evaluation, to be performed in next phase. The objectives of the activity are basically to simulate the LBLOCA reproducing the phenomena associated to the scenario and also to build a common, well-known, basis for the future comparison of uncertainty evaluation results among different methodologies and codes. The sensitivity calculations performed by participants are also presented. They allow studying the influence of different parameters such as material properties or initial and boundary conditions, upon the behaviour of the most relevant parameters related to the scenario

PREMIUM, a benchmark on the quantification of the uncertainty of the physical models in the system thermal-hydraulic codes: methodologies and data review

The objective of the Post-BEMUSE Reflood Model Input Uncertainty Methods (PREMIUM) benchmark is to progress on the issue of the quantification of the uncertainty of the physical models in system thermalhydraulic codes by considering a concrete case: the physical models involved in the prediction of core reflooding. The present document was initially conceived as a final report for the Phase I “Introduction and Methodology Review” of the PREMIUM benchmark. The objective of Phase I is to refine the definition of the benchmark and publish the available methodologies of model input uncertainty quantification relevant to the objectives of the benchmark. In this initial version the document was approved by WGAMA and has shown its usefulness during the subsequent phases of the project. Once Phase IV was completed, and following the suggestion of WGAMA members, the document was updated adding a few new sections, particularly the description of four new methodologies that were developed during this activity. Such developments were performed by some participants while contributing to PREMIUM progress (which is why this report arrives after those of other phases). After this revision the document title was changed to “PREMIUM methodologies and data review”. The introduction includes first a chapter devoted to contextualization of the benchmark in nuclear safety research and licensing, followed by a description of the PREMIUM objectives. Next, a description of the Phases in which the benchmark is divided and its organization is explained. Chapter two consists of a review of the involvement of the different participants, making a brief explanation of the input uncertainty quantification methodologies used in the activity. The document ends with some conclusions on the development of Phase I, some more general remarks and some statements on the benefits of the benchmark, which can be briefly summarized as it follows: - Contribution to development of tools and experience related to uncertainty calculation and promotion of the use of BEPU approaches for licensing and safety assessment purposes; - Contribution to prioritization of improvements to thermal-hydraulic system codes; - Contribution to a fluent and close interaction between the scientific community and regulatory organizations. Appendices include the complete description of the experimental data FEBA/SEFLEX used in the benchmark and the methodologies CIRCÉ and FFTBM and the general requirements and description specification used for Phase I. Due to the revision of the document, four extra appendixes have been added related to the methods developed during the activity, MCDA DIPE, Tractebel IUQ and PSI methods

Global molecular diversity of RSV - the "INFORM RSV" study

Background: Respiratory syncytial virus (RSV) is a global cause of severe respiratory morbidity and mortality in infants. While preventive and therapeutic interventions are being developed, including antivirals, vaccines and monoclonal antibodies, little is known about the global molecular epidemiology of RSV. INFORM is a prospective, multicenter, global clinical study performed by ReSViNET to investigate the worldwide molecular diversity of RSV isolates collected from children less than 5 years of age. Methods: The INFORM study is performed in 17 countries spanning all inhabited continents and will provide insight into the molecular epidemiology of circulating RSV strains worldwide. Sequencing of > 4000 RSV-positive respiratory samples is planned to detect temporal and geographical molecular patterns on a molecular level over five consecutive years. Additionally, RSV will be cultured from a subset of samples to study the functional implications of specific mutations in the viral genome including viral fitness and susceptibility to different monoclonal antibodies. Discussion: The sequencing and functional results will be used to investigate susceptibility and resistance to novel RSV preventive or therapeutic interventions. Finally, a repository of globally collected RSV strains and a database of RSV sequences will be created.</div

Identifying the research, advocacy, policy and implementation needs for the prevention and management of respiratory syncytial virus lower respiratory tract infection in low- and middle-income countries

Introduction: The high burden of respiratory syncytial virus (RSV) infection in young children disproportionately occurs in low- and middle-income countries (LMICs). The PROUD (Preventing RespiratOry syncytial virUs in unDerdeveloped countries) Taskforce of 24 RSV worldwide experts assessed key needs for RSV prevention in LMICs, including vaccine and newer preventive measures. Methods: A global, survey-based study was undertaken in 2021. An online questionnaire was developed following three meetings of the Taskforce panellists wherein factors related to RSV infection, its prevention and management were identified using iterative questioning. Each factor was scored, by non-panellists interested in RSV, on a scale of zero (very-low-relevance) to 100 (very-high-relevance) within two scenarios: (1) Current and (2) Future expectations for RSV management. Results: Ninety questionnaires were completed: 70 by respondents (71.4% physicians; 27.1% researchers/scientists) from 16 LMICs and 20 from nine high-income (HI) countries (90.0% physicians; 5.0% researchers/scientists), as a reference group. Within LMICs, RSV awareness was perceived to be low, and management was not prioritised. Of the 100 factors scored, those related to improved diagnosis particularly access to affordable point-of-care diagnostics, disease burden data generation, clinical and general education, prompt access to new interventions, and engagement with policymakers/payers were identified of paramount importance. There was a strong need for clinical education and local data generation in the lowest economies, whereas upper-middle income countries were more closely aligned with HI countries in terms of current RSV service provision. Conclusion: Seven key actions for improving RSV prevention and management in LMICs are proposed

Estimating in-situ material properties of a wood joist floor: Part 1 - Measurements of the real part of bending wavenumber and modulus of elasticity

This paper outlines and evaluates a non-destructive experimental technique used to obtain in-situ measures of the real part of the bending wavenumber in the two principal directions of a wood joist floor. In-situ measured wavenumbers are compared to those obtained from beam samples cut from the floor sheathing to identify the frequency range when the joists significantly affect vibration response in the floor sheathing.Wavenumber measurements confirm the highly orthotropic nature. Measurements indicate that the wavenumbers in the direction parallel to the joists are a function of location between the joists. Lower wavenumbers in this direction can be expected closer to the joists. Some discussion is given regarding the rates of attenuation with distance that can be expected parallel and perpendicular to the joists given the variation in wavenumbers, however this will be the topic of a separate paper, Part 2.Le document expose et \ue9value une technique exp\ue9rimentale non destructive utilis\ue9e pour obtenir des mesures in situ de la part r\ue9elle du nombre d'ondes de flexion dans les deux directions principales d'un plancher \ue0 solives en bois. Les nombres d'ondes mesur\ue9es in situ sont compar\ue9s \ue0 ceux obtenus \ue0 partir d'\ue9chantillons de poutre d\ue9coup\ue9s dans le rev\ueatement du plancher, pour d\ue9terminer la gamme de fr\ue9quences \ue0 laquelle les solives modifient de fa\ue7on importante la r\ue9action aux vibrations du rev\ueatement du plancher. Les mesures de nombres d'ondes confirment la nature hautement orthotrope du plancher. Elles indiquent que le nombre d'ondes dans la direction parall\ue8le aux solives sont fonction de l'endroit entre les solives. On peut s'attendre \ue0 ce que les nombres d'ondes dans cette direction soient plus faibles pr\ue8s des solives. Il est question des taux d'att\ue9nuation en fonction de la distance auxquels on peut s'attendre parall\ue8lement et perpendiculairement aux solives, \ue9tant donn\ue9 la variation des nombres d'ondes; cela sera toutefois le sujet d'un document distinct, soit la partie 2.Peer reviewed: YesNRC publication: Ye

Vibration Amplitudes in the Inuvik Powerhouse

Vibration measurements in the main powerhouse at Inuvik, NWT, were taken to determine the amplitudes of vibration present in a structure supported on pile foundations in permafrost and subjected to large dynamic periodic forces. Accelerometers were placed on the support system for the main diesel generator and on the floor and pile foundation of the one-storey industrial building. One-third octave band RMS acceleration amplitudes produced by the generator, a 5.2 MW system, are presented. In comparison to ambient acceleration amplitudes (generator off), amplitudes produced by the generator were approximately 430 times larger on the structural system supporting the generator and five to ten times larger throughout the remainder of the powerhouse.Les mesures effectu\ue9es dans la centrale \ue9lectrique d'Inuvik, Territoires du Nort-Quest, ont permi de d\ue9terminer les amplitudes des vibrations dans la structure fond\ue9e sur pieux dans le perg\ue9lisol et sujette a des forces dynamiques p\ue9riodiques. Des acc\ue9l\ue9rom\ue8tres ont \ue9t\ue9 plac\ue9s sur le support du g\ue9n\ue9rateur diesel principal et sur le plancher ainsi que sur la fondation en pieux du B\ue2timent industriel d'un \ue9tage. Le document rapporte les amplitudes de l'acc\ue9l\ue9ration (EMQ) d'une bande de fr\ue9quences d'un tiers d'octave produite par le g\ue9n\ue9rateur de 5.2 MW. Par comparaison aux amplitudes des acc\ue9l\ue9rations locales (lorsque le g\ue9n\ue9rateur est arr\ueat\ue9), les amplitudes produites par le g\ue9n\ue9rateur et environ 5 \ue0 10 fois plus importantes dans le reste de la centrale.Peer reviewed: NoNRC publication: Ye

Impact loading tests for upgrading the security of existing windows

Peer reviewed: YesNRC publication: Ye

Monitoring the behaviour of a CFRP-wrapped outdoor concrete column

Fibre-reinforced polymer laminates are now being used on a regular basis for repairs to concrete members. The laminates can be wrapped around an entire member or applied to any portion once the member has been repaired and its surface prepared to receive the laminate. However, two questions have arisen as to the suitability of the laminates in affecting a satisfactory long-term repair for concrete members; namely,a) Do the laminates alter the properties of the covered concrete or the chemical environment within the concrete, which is critical to the survival of the steel reinforcement?b) How well and for how long do the laminates bond to repaired and original concrete surfaces?To obtain some answers to these questions, the behaviour of a pair of outdoor concrete columns has been monitored since the autumn of 1999. The columns, which are over 30 years old, are located about 9-m apart beside a single lane road leading to the main entrance of a government complex in Gatineau, Quebec. In August 1999, one of the columns was covered over most of its surface with a single fabric layer of a carbon fibre-reinforced polymer (CFRP). The second was left in its existing state to serve as the control for the study.Les stratifi\ue9s de polym\ue8re renforc\ue9s de fibres sont maintenant couramment utilis\ue9s dans la r\ue9paration des structures de b\ue9ton. Le stratifi\ue9 peut envelopper enti\ue8rement la structure ou \ueatre appliqu\ue9 sur une partie, une fois la surface de la structure r\ue9par\ue9e et pr\ueate \ue0 recevoir le stratifi\ue9. Deux questions se posent toutefois quant \ue0 l'efficacit\ue9 \ue0 long terme du stratifi\ue9 dans la r\ue9paration des structures de b\ue9ton :a) Le stratifi\ue9 alt\ue8re-t-il les propri\ue9t\ue9s du b\ue9ton qu'il recouvre ou l'environnement chimique du b\ue9ton, lequel est d\ue9terminant dans la survie de l'armature?b) Quelle est l'efficacit\ue9 et la dur\ue9e de vie du rev\ueatement stratifi\ue9 des surfaces de b\ue9ton r\ue9par\ue9es ou d'origine?Afin de trouver des r\ue9ponses \ue0 ces questions, deux colonnes de b\ue9ton ext\ue9rieures sont sous observation depuis l'automne 1999. Les colonnes, vieilles de 30 ans et s\ue9par\ue9es de 9 m\ue8tres l'une de l'autre, sont situ\ue9es pr\ue8s d'une voie \ue0 sens unique menant \ue0 l'entr\ue9e principale d'un complexe d'\ue9difices gouvernementaux de Gatineau, au Qu\ue9bec. En ao\ufbt 1999, l'une des colonnes a \ue9t\ue9 recouverte presque en totalit\ue9 d'une couche de polym\ue8re renforc\ue9 de fibres de carbone (PRFC). La seconde n'a pas \ue9t\ue9 touch\ue9e pour les besoins de l'analyse.Peer reviewed: YesNRC publication: Ye

Long-term monitoring of a CFRP-wrapped concrete column

Fibre-reinforced polymer laminates are now used on a regular basis for repairs to concrete members. The laminates can be wrapped around an entire member or applied to any portion once the member has been repaired and its surface properly prepared to receive the laminate. However, two questions have arisen as to the suitability of the laminates in affecting a satisfactory long-term repair for concrete members; namely,i) Do the laminates alter the properties of the concrete or the chemical environment within the concrete, which is critical to the survival of the steel reinforcement?ii) How well and for how long do the laminates bond to repaired and original concrete surfaces?To obtain some answers to these questions, the performance of a pair of square concrete columns has been monitored since 1996. The columns straddle an expansion joint within a heated multi-level, underground parking garage in Gatineau, Quebec. About a year after extensive repairs were made to the concrete structure, one column was completely covered with a carbon fibre-reinforced polymer (CFRP) and the second left in its reconditioned state to serve as the control for the study. A data acquisition system comprising a multi-channel data recorder and an array of relative humidity and temperature sensors and strain gauges was installed to continuously monitor conditions in the columns. In addition, annual non-destructive electro-chemical and sonic surveys were conducted on the columns to assist in examining the effects of the laminate. As pull-off tests on the wrapped column were undesirable because of the need to patch and reseal tested areas, a set of concrete specimens, divided into garage and control samples, was coated with the laminate and tested yearly to monitor pull-off strength. This paper will present the data collected during the past six years and discuss the effects of the laminate on the conditions and properties of a concrete.Les stratifi\ue9s en polym\ue8re renforc\ue9s \ue0 la fibre de verre sont aujourd'hui utilis\ue9s couramment pour r\ue9parer les \ue9l\ue9ments en b\ue9ton. Les stratifi\ue9s peuvent \ueatre enroul\ue9s autour de l'\ue9l\ue9ment ou appliqu\ue9s sur une zone pr\ue9cise une fois que l'\ue9l\ue9ment a \ue9t\ue9 r\ue9par\ue9 et que la surface a \ue9t\ue9 appr\ueat\ue9e pour recevoir le stratifi\ue9. Deux questions toutefois se posent quant \ue0 la viabilit\ue9 des stratifi\ue9s comme m\ue9thode de r\ue9paration \ue0 long terme des \ue9l\ue9ments en b\ue9ton :i) les stratifi\ue9s alt\ue8rent-ils les propri\ue9t\ue9s du b\ue9ton ou du milieu chimique \ue0 l'int\ue9rieur du b\ue9ton, lequel est essentiel \ue0 la survie des armatures en acier?ii) l'adh\ue9rence des stratifi\ue9s aux surfaces de b\ue9ton r\ue9par\ue9es et d'origine est-elle bonne et durable?Pour obtenir quelques r\ue9ponses \ue0 ces questions, on surveille depuis 1996 la performance de deux poteaux en b\ue9ton de section carr\ue9e. Les poteaux chevauchent un joint de dilatation dans un garage de stationnement souterrain chauff\ue9 \ue0 plusieurs niveaux situ\ue9 \ue0 Gatineau, au Qu\ue9bec. Environ un an apr\ue8s que des r\ue9parations importantes aient \ue9t\ue9 ex\ue9cut\ue9es sur les ouvrages en b\ue9ton, un poteau a \ue9t\ue9 enti\ue8rement recouvert d'un polym\ue8re renforc\ue9 de fibres de carbone et le second, laiss\ue9 en l'\ue9tat pour servir de t\ue9moin aux fins de l'\ue9tude. On a install\ue9 un syst\ue8me d'acquisition de donn\ue9es comprenant un enregistreur de donn\ue9es multivoie et un r\ue9seau de capteurs d'humidit\ue9 et de temp\ue9rature et de jauges de d\ue9formation afin de surveiller un continu les conditions \ue0 l'int\ue9rieur des poteaux. On a en outre men\ue9 chaque ann\ue9e une \ue9tude \ue9lectrochimique non destructive et effectu\ue9 des relev\ue9s soniques pour examiner les effets du stratifi\ue9. Si l'on avait men\ue9 des essais de d\ue9collement sur les poteaux envelopp\ue9s, il aurait ensuite fallu ragr\ue9er et resceller les zones d'essai. On a donc jug\ue9 pr\ue9f\ue9rable d'enrober de stratifi\ue9 un ensemble d'\ue9chantillons de b\ue9ton, soit des \ue9chantillons provenant du garage et des \ue9chantillons t\ue9moins et de les soumettre \ue0 des essais annuels pour en d\ue9terminer la r\ue9sistance au d\ue9collement. Le pr\ue9sent rapport expose les donn\ue9es recueillies au cours des six derni\ue8res ann\ue9es et examine les effets du stratifi\ue9 sur les conditions et les propri\ue9t\ue9s du b\ue9ton.Peer reviewed: YesNRC publication: Ye