[116] THERMAL-HYDRAULIC PHENOMENA

FOREWORD & SCOPE ISSUED PAPER J NED 2018 ORIGINATING DOCS/ BRIEF HISTORY 116 PHENOMENA (TH-P) LIST CROSS-LINKING Reactor Types, TH-P, Accident Scenarios and Parameters CONCLUSIONS & PROPOSED DEVELOPMENTS ACKNOWLEDGEMENT

NURETH-15, Pisa (Italy), May 12-17, 2013 – Summary

Summary information about NURETH-15 Conference is provided in the present document. This intends to cover the conduct of the Conference and to provide highlights about the planning. Insights from the technical-scientific content of the papers and financial report shall be the subject of forthcoming documents. More details can be found on the website www.NURETH15.org. 1. Conference Conduct The NURETH-15 Conference has been held in Pisa May 12-17, 2013. F. D’Auria (General Chair) opened the Conference. The Welcome Address Session was chaired by M. Cumo (Honorary Chair together with N. Todreas). Key design features of the Conference are listed below: The Conference venue included three cities in Tuscany, Florence (‘Corsini Palace’), Lucca (‘Regio Collegio’) and Pisa with four locations (Verdi Theater, Congress Palace, Former Railway Station ‘Leopolda’ and Church ‘Del Carmine’). This needed special logistic arrangements including close attention at each cross-point. Specific Conference plans included: - Student Sessions. - Selection of NURETH Fellows (among around 6000 authors of all NURETH Conferences, since NURETH-1 in 1980, see below). - Poster Session. - Invited Speakers as distinguished Lecturers and Chairmen introducing the key Plenary Sessions. - Pre-Conference and Post-Conference Workshops. Committees were formed previous to Conference dates and worked during the Conference: - To select the Best Poster papers, Chair Y. Hassan (three awards given, see below). - To select the Best Oral papers, Chair N. Aksan (three awards given, see below). - To select the Best Student papers, Chair N. Cavlina (three awards given, see below). - To plan Technical Journal publication of selected papers, Chair N. Aksan (also expected to work after the Conference). A NURETH poster was created including the names of all NURETH authors (from NURETH-1 to NURETH-15, around 6000 scientists as already mentioned) and pictures from each NURETH Conference. About five hundred scientists, 432 registered participants with payment, NURETH Fellows (the list of those attending is provided below), selected Invited Speakers and undergraduate students from University of Pisa (who also served as stewards in each of the Conference sessions and places), attended the NURETH-15 Conference

A view on identification of thermal-hydraulic phenomena for validation of best-estimate computer codes

Validation of best-estimate codes is a necessary step to prove their applicability to calculate accident scenarios, including the course of events. It shall demonstrate that those physical phenomena, which are important for a scenario, are calculated appropriately. A common list of 113 thermal-hydraulic phenomena is provided, based on previous reports of OECD/NEA-CSNI and IAEA, including Separate Effects Test (SET) facilities and Integral Test facilities of PWRs and BWRs, VVERs, Advanced Reactors, as well as Containment. Added objective of the activity is to show that the list of phenomena is applicable to the major number of water-cooled reactors. Twelve reactor types are considered for the characterization of 47 accident scenarios cross-linked with the identified phenomena. Focus of this paper is on the updated identification of the list of thermal-hydraulic phenomena

FONESYS and SILENCE Networks: Looking to the Future of T-H Code Development and Experimentation

The purpose of this paper is to present briefly the projects called FONESYS (Forum & Network of System Thermal-Hydraulics Codes in Nuclear Reactor Thermal-Hydraulics) and SILENCE (Significant Light and Heavy Water Reactor Thermal Hydraulic Experiments Network for the Consistent Exploitation of the Data), their participants, their motivations, their main targets and working modalities. System Thermal-Hydraulics (SYS-TH) codes, also as part of the Best Estimate Plus Uncertainty (BEPU) approaches, are expected to achieve a more-and-more relevant role in nuclear reactor safety and design technology. Namely, the number of code-users is likely to increase in the countries where nuclear technology is exploited. Thus, the idea of establishing a forum and a network among the code developers and with possible extension to code users has started to have major importance and value. In this framework, the FONESYS initiative has been launched in 2010 aiming at creation of a common ground for discussing current limitations and envisaged improvements in various areas of SYS-TH and their application in the licensing process and safety analysis. According to FONESYS statute, there are seven signatory Institutions and two observer Institutions currently participating in the project. Signatory Institutions are AREVA-NP, Commissariat à l’Énergie Atomique et aux Énergies Alternatives (CEA), San Piero a Grado Nuclear Research Group - University of Pisa (GRNSPG-UNIPI), Gesellschaft für Anlagenund Reaktorsicherheit (GRS), Korea Atomic Energy Research Institute (KAERI), Korea Institute of Nuclear Safety (KINS), and VTT Technical Research Centre of Finland. SILENCE is a network that intends to promote the cooperation among teams of experimentalists managing or involved in significant experimental projects in nuclear reactor thermal-hydraulics, with the aim to contrast the risk of losing expertise and vision in this important area of the nuclear technology. This network was launched in 2012, replicating for the TH experimental domain the role that FONESYS plays in the code-development domain. Currently, the following Organizations are Members of SILENCE: AREVA GmbH, Helmholtz Zentrum Dresden-Rossendorf (HZDR), Korea Atomic Energy Research Institute (KAERI), Hungarian Academy of Sciences Centre for Energy Research (MTA EK),Lappeenranta University of Technology (LUT), and Paul Scherrer Institute (PSI). SILENCE is currently organizing a “Specialists Workshop on Advanced Instrumentation and Measurement Techniques for Nuclear Reactor Thermal Hydraulics” (SWINTH-2016). The San Piero a Grado Nuclear Research Group - University of Pisa (GRNSPG-UNIPI) is the Host Institution and plays as a Scientific Secretariat for both Networks

Pilot Results on Forward Collision Warning System Effectiveness in Older Drivers

Advanced Driver Assistance Systems (ADAS) have largely been developed with a “one-size-fits-all” approach. This approach neglects the large inter-individual variability in perceptual and cognitive abilities that affect aging ADAS users. We investigated the effectiveness of a forward collision warning (FCW) with fixed response parameters in young and older drivers with differing levels of cognitive functioning. Drivers responded to a pedestrian stepping into the driver’s path on a simulated urban road. Behavioral metrics included response times (RT) for pedal controls and two indices of risk penetration (e.g., maximum deceleration and minimum time-to-collision (TTC)). Older drivers showed significantly slower responses at several time points compared to younger drivers. The FCW facilitated response times (RTs) for older and younger drivers. However, older drivers still showed smaller safety gains compared to younger drivers at accelerator pedal release and initial brake application when the FCW was active. No significant differences in risk metrics were observed within the condition studied. The results demonstrate older drivers likely differ from younger drivers using a FCW with a fixed parameter set. Finally, we briefly discuss how future research should examine predictive relationships between domains of cognitive functioning and ADAS responses to develop parameter sets to fit the individual

Prospective For Nuclear Thermal Hydraulic Created By Ongoing And New Networks

International audienceThis paper introduces the FONESYS, SILENCE and CONUSAF projects run by some of the leading organizations working in the nuclear sector.The FONESYS members are developers of some of the major System Thermal-Hydraulic (SYS-TH) codes adopted worldwide, whereas the SILENCE members own and operate important thermal-hydraulic experimental facilities. The two networks work in a cooperative manner and have at least one meeting per year where top-level experts in the areas of thermal-hydraulic code development and experimentation are gathered.The FONESYS members address various topics such as hyperbolicity and numerics in SYS-TH codes, 3-field modeling, transport of interfacial area, 3D modeling, scaling of thermal-hydraulic phenomena, two-phase critical flow (TPCF), critical heat flux (CHF), and others. As part of the working modalities, some numerical benchmarks were proposed and successfully conducted by the network, addressing some of the most relevant topics selected by the FONESYS members.On the other hand, SILENCE addresses topics such as identification of current measurement needs and main gaps for further SYS-TH and CFD codes development and validation, definition of similar tests and counterpart tests in Integral Tests Facilities (including containment thermal-hydraulics) to be possibly conducted on Members' test facilities, scaling issue, and other subjects. Furthermore, SILENCE organized a Specialists Workshop on Advanced Instrumentation and Measurement Techniques for Nuclear Reactor Thermal-Hydraulics (SWINTH) which was held in Italy on June 2016. A second edition of the Workshop, namely SWINTH-2019, will be held in Italy in 2019 under the umbrella of the OECD/NEA/CSNI/WGAMA.Recently a new initiative is being taken by launching an international consortium of nuclear thermal-hydraulics code users, the CONUSAF. The main idea is to enhance the interactions between the users of computational tools in nuclear TH, noticeably including SYS-TH and CFD codes, the code developers and the experimentalists. The proposed initiative is expected to have a positive impact on the entire ecosystem by pursuing the assessment of the current code limitations and capabilities, analyzing and addressing issues raised by the users and promoting common RandD efforts on topics of high relevance

Critical flow prediction by system codes – Recent analyses made within the FONESYS network

A benchmark activity on Two-Phase Critical Flow (TPCF) prediction was conducted in the framework of the Forum & Network of System Thermal-Hydraulics Nuclear Reactor Thermal-Hydraulics (FONESYS). FONESYS is a network among code developers who share the common objective to strengthen current technology. The aim of the FONESYS Network is to highlight the capabilities and the robustness as well as the limitations of current SYSTH codes to predict the main phenomena during transient scenarios in nuclear reactors for safety issues. Six separate effect test facilities, more than 90 tests, both in steady and transient conditions, were considered for the activity. Moreover, two ideal tests were designed for code to code comparison in clearly defined conditions. Overall eight System Thermal-Hydraulic (SYS-TH) codes were adopted, mostly by the developers themselves, ensuring the minimization of the user effect. Results from selected tests were also compared against Delayed Equilibrium Model, not yet implemented in industrial version of SYS-TH codes. Generally, the results of the benchmark show an improvement of the capability of SYS-TH codes to predict TPCF in the last three decades. However, predicting break flowrate remains a major source of uncertainty in accidental transient simulations of Water-Cooled Nuclear Reactors (WCNR). A set of possible actions is proposed to go beyond the current limitations of choked flow models. More detailed guidelines for using 0-D choked flow models is possible by using the experience gained by the benchmark results as well as all available validation results. Progress in understanding and 1-D modelling of flashing and choked flow might be achieved by a deeper physical analysis leading to more mechanistic models based on specific flow regime maps for high speed flow. Also the use of advanced 3-D numerical tools may help to understand and predict the complex 3-D geometrical effect

Lymph node metastasis in grossly apparent clinical stage Ia epithelial ovarian cancer: Hacettepe experience and review of literature

Background Lymphadenectomy is an integral part of the staging system of epithelial ovarian cancer. However, the extent of lymphadenectomy in the early stages of ovarian cancer is controversial. The objective of this study was to identify the lymph node involvement in unilateral epithelial ovarian cancer apparently confined to the one ovary (clinical stage Ia). Methods A prospective study of clinical stage I ovarian cancer patients is presented. Patient's characteristics and tumor histopathology were the variables evaluated. Results Thirty three ovarian cancer patients with intact ovarian capsule were evaluated. Intraoperatively, neither of the patients had surface involvement, adhesions, ascites or palpable lymph nodes (supposed to be clinical stage Ia). The mean age of the study group was 55.3 ± 11.8. All patients were surgically staged and have undergone a systematic pelvic and paraaortic lymphadenectomy. Final surgicopathologic reports revealed capsular involvement in seven patients (21.2%), contralateral ovarian involvement in two (6%) and omental metastasis in one (3%) patient. There were two patients (6%) with lymph node involvement. One of the two lymph node metastasis was solely in paraaortic node and the other metastasis was in ipsilateral pelvic lymph node. Ovarian capsule was intact in all of the patients with lymph node involvement and the tumor was grade 3. Conclusion In clinical stage Ia ovarian cancer patients, there may be a risk of paraaortic and pelvic lymph node metastasis. Further studies with larger sample size are needed for an exact conclusion.PubMedWoSScopu

The training needs of Turkish emergency department personnel regarding intimate partner violence

<p>Abstract</p> <p>Background</p> <p>Violence against females is a widespread public health problem in Turkey and the lifetime prevalence of IPV ranges between 34 and 58.7%. Health care workers (HCW) sometimes have the unique opportunity and obligation to identify, treat, and educate females who are abused. The objective of this study was to evaluate the knowledge, attitudes, and experiences of the emergency department (ED) staff regarding intimate partner violence (IPV) at a large university hospital in Turkey.</p> <p>Methods</p> <p>A cross-sectional study was conducted in a large university hospital via questionnaire. The study population consisted of all the nurses and physicians who worked in the ED during a two month period (n = 215). The questionnaire response rate was 80.5% (41 nurses and 132 physicians). The main domains of the questionnaire were knowledge regarding the definition of IPV, clinical findings in victims of IPV, legal aspects of IPV, attitudes towards IPV, knowledge about the characteristics of IPV victims and abusers, and professional and personal experiences and training with respect to IPV.</p> <p>Results</p> <p>One-half of the study group were females, 76.3% were physicians, and 89.8% had no training on IPV. The majority of the nurses (89.5%) and physicians (71.1%) declared that they were aware of the clinical appearance of IPV. The mean of the knowledge scores on clinical knowledge were 8.84 ± 1.73 (range, 0–10) for acute conditions, and 4.51 ± 3.32 for chronic conditions. The mean of the knowledge score on legal procedures and the legal rights of the victims was 4.33 ± 1.66 (range, 0–7). At least one reason to justify physical violence was accepted by 69.0% of females and 84.7% of males, but more males than females tended to justify violence (chi square = 5.96; p = 0.015). However, both genders accepted that females who experienced physical violence should seek professional medical help.</p> <p>Conclusion</p> <p>The study participants' knowledge about IPV was rather low and a training program is thus necessary on this issue. Attention must be given to the legal aspects and clinical manifestations of IPV. The training program should also include a module on gender roles in order to improve the attitudes towards IPV.</p

Laser-induced modification of the patellar ligament tissue: comparative study of structural and optical changes

The effects of non-ablative infrared (IR) laser treatment of collagenous tissue have been commonly interpreted in terms of collagen denaturation spread over the laser-heated tissue area. In this work, the existing model is refined to account for the recently reported laser-treated tissue heterogeneity and complex collagen degradation pattern using comprehensive optical imaging and calorimetry toolkits. Patella ligament (PL) provided a simple model of type I collagen tissue containing its full structural content from triple-helix molecules to gross architecture. PL ex vivo was subjected to IR laser treatments (laser spot, 1.6 mm) of equal dose, where the tissue temperature reached the collagen denaturation temperature of 60 ± 2°C at the laser spot epicenterin the first regime, and was limited to 67 ± 2°C in the second regime. The collagen network was analyzed versus distance from the epicenter. Experimental characterization of the collagenous tissue at all structural levels included cross-polarization optical coherence tomography, nonlinear optical microscopy, light microscopy/histology, and differential scanning calorimetry. Regressive rearrangement of the PL collagen network was found to spread well outside the laser spot epicenter (>2 mm) and was accompanied by multilevel hierarchical reorganization of collagen. Four zones of distinct optical and morphological properties were identified, all elliptical in shape, and elongated in the direction perpendicular to the PL long axis. Although the collagen transformation into a random-coil molecular structure was occasionally observed, it was mechanical integrity of the supramolecular structures that was primarily compromised. We found that the structural rearrangement of the collagen network related primarily to the heat-induced thermo-mechanical effects rather than molecular unfolding. The current body of evidence supports the notion that the supramolecular collagen structure suffered degradation of various degrees, which gave rise to the observed zonal character of the laser-treated lesion