Perspectives in System Thermal-Hydraulics

F. D’AURIA 한국원자력학회 2012 Nuclear Engineering and Technology Vol.44 No.8

The paper deals with three main topics: a) the definition of System Thermal-Hydraulics (SYS TH), b) a historical outline for SYS TH and, c) the description of elements for reflection when planning research projects or improvement activities, this last topic being the main reason for the paper. Distinctions between basic thermal-hydraulics and computational Fluid-Dynamics (CFD) on the one side and SYS TH on the other side are considered under the first topic; stakeholders in the technology are identified. The proposal of Interim Acceptance Criteria for Emergency Core Cooling Systems in 1971 by US NRC (AEC at the time) is recognized as the starting date or the triggering event for SYS TH (second topic). The complex codes and the main experimental programs (list provided in the paper) constitute the pillars for SYS TH. Caution or warning statements are introduced in advance when discussing the third topic: a single person (or a researcher) has little to no possibility,or capability, of streamlining the forthcoming investments or to propose a roadmap for future activities. Nevertheless, the ambitious attempt to foresee developments in this area has been pursued without constraints connected with the availability of funds and with industrial benefits or interests. Demonstrating the acceptability of current SYS TH limitations and training in the application of those codes are mentioned as the main challenges for forthcoming research activities.

SCALING ANALYSIS IN BEPU LICENSING OF LWR

FRANCESCO D’AURIA,MARCO LANFREDINI,NIKOLAUS MUELLNER 한국원자력학회 2012 Nuclear Engineering and Technology Vol.44 No.6

“Scaling” plays an important role for safety analyses in the licensing of water cooled nuclear power reactors. Accident analyses, a sub set of safety analyses, is mostly based on nuclear reactor system thermal hydraulics, and therefore based on an adequate experimental data base, and in recent licensing applications, on best estimate computer code calculations. In the field of nuclear reactor technology, only a small set of the needed experiments can be executed at a nuclear power plant; the major part of experiments, either because of economics or because of safety concerns, has to be executed at reduced scale facilities. How to address the scaling issue has been the subject of numerous investigations in the past few decades (a lot of work has been performed in the 80thies and 90thies of the last century), and is still the focus of many scientific studies. The present paper proposes a “roadmap” to scaling. Key elements are the “scaling-pyramid”, related “scaling bridges” and a logical path across scaling achievements (which constitute the “scaling puzzle”). The objective is addressing the scaling issue when demonstrating the applicability of the system codes, the “key-to-scaling”, in the licensing process of a nuclear power plant. The proposed “road map to scaling” aims at solving the “scaling puzzle”, by introducing a unified approach to the problem.

PERSPECTIVES IN SYSTEM THERMAL-HYDRAULICS

D'auria, F. Korean Nuclear Society 2012 Nuclear Engineering and Technology Vol.44 No.8

The paper deals with three main topics: a) the definition of System Thermal-Hydraulics (SYS TH), b) a historical outline for SYS TH and, c) the description of elements for reflection when planning research projects or improvement activities, this last topic being the main reason for the paper. Distinctions between basic thermal-hydraulics and computational Fluid-Dynamics (CFD) on the one side and SYS TH on the other side are considered under the first topic; stakeholders in the technology are identified. The proposal of Interim Acceptance Criteria for Emergency Core Cooling Systems in 1971 by US NRC (AEC at the time) is recognized as the starting date or the triggering event for SYS TH (second topic). The complex codes and the main experimental programs (list provided in the paper) constitute the pillars for SYS TH. Caution or warning statements are introduced in advance when discussing the third topic: a single person (or a researcher) has little to no possibility, or capability, of streamlining the forthcoming investments or to propose a roadmap for future activities. Nevertheless, the ambitious attempt to foresee developments in this area has been pursued without constraints connected with the availability of funds and with industrial benefits or interests. Demonstrating the acceptability of current SYS TH limitations and training in the application of those codes are mentioned as the main challenges for forthcoming research activities.

STATE OF THE ART IN USING BEST ESTIMATE CALCULATION TOOLS IN NUCLEAR TECHNOLOGY

D'AURIA FRANCESCO,ANIS BOUSBIA-SALAH,PETRUZZI ALESSANDRO,NEVO ALESSANDRO DEL Korean Nuclear Society 2006 Nuclear Engineering and Technology Vol.38 No.1

System thermal-hydraulic codes have been used in the past decades in the areas of design, operation, licensing and safety of Nuclear Power Plants (NPPs). The development and validation of these codes have reached a high degree of maturity, through the consideration of huge experiments and advanced numerical models. Nowadays, the analyses are based upon realistic approaches rather than the conservative evaluation models. However the applications of these computational tools require preliminary qualification issues. Although huge amounts of financial and human resources have been invested for the development and improvement of codes, the calculation results are still affected by errors. In the sophisticated nuclear technology, design and safety of NPP, these errors must be quantified. An overview of the state of the art of the current thermal-hydraulic system code is developed and the need of uncertainty analysis in code calculations is emphasized. Several sources of uncertainty have been classified and commented, and typical applications of such methods are shown.

SCALING ANALYSIS IN BEPU LICENSING OF LWR

D'auria, Francesco,Lanfredini, Marco,Muellner, Nikolaus Korean Nuclear Society 2012 Nuclear Engineering and Technology Vol.44 No.6

"Scaling" plays an important role for safety analyses in the licensing of water cooled nuclear power reactors. Accident analyses, a sub set of safety analyses, is mostly based on nuclear reactor system thermal hydraulics, and therefore based on an adequate experimental data base, and in recent licensing applications, on best estimate computer code calculations. In the field of nuclear reactor technology, only a small set of the needed experiments can be executed at a nuclear power plant; the major part of experiments, either because of economics or because of safety concerns, has to be executed at reduced scale facilities. How to address the scaling issue has been the subject of numerous investigations in the past few decades (a lot of work has been performed in the 80thies and 90thies of the last century), and is still the focus of many scientific studies. The present paper proposes a "roadmap" to scaling. Key elements are the "scaling-pyramid", related "scaling bridges" and a logical path across scaling achievements (which constitute the "scaling puzzle"). The objective is addressing the scaling issue when demonstrating the applicability of the system codes, the "key-to-scaling", in the licensing process of a nuclear power plant. The proposed "road map to scaling" aims at solving the "scaling puzzle", by introducing a unified approach to the problem.

STATE OF THE ART IN USING BEST ESTIMATECALCULATION TOOLS IN NUCLEAR TECHNOLOGY

FRANCESCO D'AURIA, ANIS BOUSBIA-SALAH, ALESSANDRO PETRUZZI, ALESSANDRO DEL NEVO 한국원자력학회 2006 Nuclear Engineering and Technology Vol.38 No.1

Transanal Hemorrhoidal Dearterialization With Doppler Arterial Identification Versus Classic Hemorrhoidectomy: A Retrospective Analysis of 270 Patients

Vincenzo Consalvo,Francesca D’Auria,Vincenzo Salsano 대한대장항문학회 2019 Annals of Coloproctolgy Vol.35 No.3

Purpose: Despite the minimally invasive nature of transanal hemorrhoidal dearterialization (THD) with Doppler arterial identification procedures, hemorrhoidectomy is still considered the gold standard procedure for hemorrhoidal disease. However, the classical techniques of hemorrhoidectomy have a high rate of postoperative complications. The main purpose of this study is to demonstrate the efficacy and complications of these techniques used for grades II and III hemorrhoids. Methods: A retrospective (case-control) study was carried out from January 2009 to May 2014, and all patients undergoing surgical procedures for hemorrhoidal disease in two French clinics were considered. Application of inclusion and exclusion criteria identified 270 eligible patients (163 undergoing Doppler THD and 107 treated with Milligan Morgan hemorrhoidectomy). Statistical analysis was calculated considering immediate postoperative complications, functional results, chronic complications, and recurrences. Results: Analysis of primary outcomes showed a significant difference between the 2 groups concerning postoperative pain, which had a lower rate in THD (P = 0.0001) and in postoperative bleeding (P = 0.02) than hemorrhoidectomy. However, long-term follow-up at three years showed a superior rate of recurrence in the THD group (P = 0.009). Conclusion: The THD technique is a safe and effective procedure for grades II and III hemorrhoids, has lower rates of post-operative pain and bleeding, and allows faster hospital discharge; however, it also shows a higher rate of recurrence at three years of follow-up.

INTERNATIONAL STANDARD PROBLEM 50: THE UNIVERSITY OF PISA CONTRIBUTION

Cherubini, Marco,Lazzerini, Davide,Giannotti, Walter,D'auria, Francesco Korean Nuclear Society 2012 Nuclear Engineering and Technology Vol.44 No.6

The present paper deals with the participation of the University of Pisa in the last International Standard Problem (ISP) focused on system thermal hydraulic, which was led by the Korean Atomic Energy Research Institution (KAERI). The selected test was a Direct Vessel Injection (DVI) line break carried out at the ATLAS facility. University of Pisa participated, together with other eighteen institutions, in both blind and open phase of the analytical exercise pursuing its methodology for developing and qualifying a nodalization. Qualitative and quantitative analysis of the code results have been performed for both ISP-50 phases, the latter adopting the Fast Fourier Transfer Based Method (FFTBM). The experiment has been characterized by three-dimensional behavior in downcomer and core region. Even though an attempt to reproduce these phenomena, by developing a fictitious three-dimensional nodalization has been realized, the obtained results were generally acceptable but not fully satisfactory in replicating 3D behavior.

Poster Session : Biotechnology ; Fluorescence resonance energy transfer from fluorescein-Labeled anti-tTG to QSY 7-Labeled tTG

( Jung Sook Kang ),( Jae Hui Kim ),( Sabato D`Auria ),( Antonio Varriale ),( Mauro Rossi ) 한국생화학분자생물학회 (구 한국생화학회) 2007 생화학분자생물학회 춘계학술발표논문집 Vol.2007 No.-

INTERNATIONAL STANDARD PROBLEM 50: THE UNIVERSITY OF PISA CONTRIBUTION

MARCO CHERUBINI,DAVIDE LAZZERINI,WALTER GIANNOTTI,FRANCESCO D’AURIA 한국원자력학회 2012 Nuclear Engineering and Technology Vol.44 No.6

The present paper deals with the participation of the University of Pisa in the last International Standard Problem (ISP)focused on system thermal hydraulic, which was led by the Korean Atomic Energy Research Institution (KAERI). The selected test was a Direct Vessel Injection (DVI) line break carried out at the ATLAS facility. University of Pisa participated, together with other eighteen institutions, in both blind and open phase of the analytical exercise pursuing its methodology for developing and qualifying a nodalization. Qualitative and quantitative analysis of the code results have been performed for both ISP-50phases, the latter adopting the Fast Fourier Transfer Based Method (FFTBM). The experiment has been characterized by threedimensional behavior in downcomer and core region. Even though an attempt to reproduce these phenomena, by developing a fictitious three-dimensional nodalization has been realized, the obtained results were generally acceptable but not fully satisfactory in replicating 3D behavior.